Al,
could you please make sure you are happy with the current version of the
richacl patch queue for the next merge window?
Changes since the last posting (https://lwn.net/Articles/671398/):
* Some combinations of ACL entry flags were not computed correctly when
ACL entries were inherited from a directory to files and directories
created inside that directory. This is fixed now, with a test case
covering all the flag combinations in the richacl package.
* Rebases on top of v4.5-rc5.
The complete patch queue is available here:
git://git.kernel.org/pub/scm/linux/kernel/git/agruen/linux-richacl.git \
richacl-2016-02-22
The richacl user-space utilitites, man pages, and test suite are available
here:
https://github.com/andreas-gruenbacher/richacl
Changes to other user-space packages for richacl:
https://github.com/andreas-gruenbacher/coreutils
https://github.com/andreas-gruenbacher/e2fsprogs
https://github.com/andreas-gruenbacher/xfsprogs-dev
https://github.com/andreas-gruenbacher/nfs-utils
Please see the richacl homepage for more information:
http://www.bestbits.at/richacl/
Thanks,
Andreas
Andreas Gruenbacher (20):
vfs: Add IS_ACL() and IS_RICHACL() tests
vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags
vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
vfs: Make the inode passed to inode_change_ok non-const
vfs: Add permission flags for setting file attributes
richacl: In-memory representation and helper functions
richacl: Permission mapping functions
richacl: Compute maximum file masks from an acl
richacl: Permission check algorithm
posix_acl: Unexport acl_by_type and make it static
vfs: Cache base_acl objects in inodes
vfs: Add get_richacl and set_richacl inode operations
vfs: Cache richacl in struct inode
richacl: Update the file masks in chmod()
richacl: Check if an acl is equivalent to a file mode
richacl: Create-time inheritance
richacl: Automatic Inheritance
richacl: xattr mapping functions
richacl: Add richacl xattr handler
vfs: Add richacl permission checking
Aneesh Kumar K.V (2):
ext4: Add richacl support
ext4: Add richacl feature flag
drivers/staging/lustre/lustre/llite/llite_lib.c | 2 +-
fs/Kconfig | 3 +
fs/Makefile | 2 +
fs/attr.c | 81 +++-
fs/ext4/Kconfig | 11 +
fs/ext4/Makefile | 1 +
fs/ext4/ext4.h | 6 +-
fs/ext4/file.c | 3 +
fs/ext4/ialloc.c | 11 +-
fs/ext4/inode.c | 12 +-
fs/ext4/namei.c | 5 +
fs/ext4/richacl.c | 142 ++++++
fs/ext4/richacl.h | 40 ++
fs/ext4/super.c | 49 +-
fs/ext4/xattr.c | 7 +
fs/f2fs/acl.c | 4 +-
fs/inode.c | 15 +-
fs/jffs2/acl.c | 10 +-
fs/namei.c | 118 ++++-
fs/posix_acl.c | 50 +-
fs/richacl_base.c | 580 ++++++++++++++++++++++++
fs/richacl_inode.c | 333 ++++++++++++++
fs/richacl_xattr.c | 235 ++++++++++
fs/xattr.c | 29 +-
include/linux/fs.h | 60 ++-
include/linux/posix_acl.h | 13 +-
include/linux/richacl.h | 208 +++++++++
include/linux/richacl_xattr.h | 31 ++
include/uapi/linux/Kbuild | 2 +
include/uapi/linux/fs.h | 3 +-
include/uapi/linux/richacl.h | 152 +++++++
include/uapi/linux/richacl_xattr.h | 44 ++
include/uapi/linux/xattr.h | 2 +
33 files changed, 2157 insertions(+), 107 deletions(-)
create mode 100644 fs/ext4/richacl.c
create mode 100644 fs/ext4/richacl.h
create mode 100644 fs/richacl_base.c
create mode 100644 fs/richacl_inode.c
create mode 100644 fs/richacl_xattr.c
create mode 100644 include/linux/richacl.h
create mode 100644 include/linux/richacl_xattr.h
create mode 100644 include/uapi/linux/richacl.h
create mode 100644 include/uapi/linux/richacl_xattr.h
--
2.4.3
Cache richacls in struct inode so that this doesn't have to be done
individually in each filesystem. This is similar to POSIX ACLs.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/inode.c | 11 +++++--
fs/posix_acl.c | 2 +-
fs/richacl_inode.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 5 +++-
include/linux/richacl.h | 6 ++++
5 files changed, 96 insertions(+), 5 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 101d806..de80116 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -180,8 +180,11 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_private = NULL;
inode->i_mapping = mapping;
INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
-#ifdef CONFIG_FS_POSIX_ACL
- inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
+ inode->i_acl = ACL_NOT_CACHED;
+# if defined(CONFIG_FS_POSIX_ACL)
+ inode->i_default_acl = ACL_NOT_CACHED;
+# endif
#endif
#ifdef CONFIG_FSNOTIFY
@@ -237,11 +240,13 @@ void __destroy_inode(struct inode *inode)
atomic_long_dec(&inode->i_sb->s_remove_count);
}
-#ifdef CONFIG_FS_POSIX_ACL
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
base_acl_put(inode->i_acl);
+# if defined(CONFIG_FS_POSIX_ACL)
if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
base_acl_put(inode->i_default_acl);
+# endif
#endif
this_cpu_dec(nr_inodes);
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 743b6dc..f24646e 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -37,7 +37,7 @@ struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
struct base_acl **p = acl_by_type(inode, type);
struct base_acl *acl = ACCESS_ONCE(*p);
- if (acl) {
+ if (acl && IS_POSIXACL(inode)) {
spin_lock(&inode->i_lock);
acl = *p;
if (acl != ACL_NOT_CACHED)
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index 99b3c93..52c1595 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -20,6 +20,83 @@
#include <linux/slab.h>
#include <linux/richacl.h>
+struct richacl *get_cached_richacl(struct inode *inode)
+{
+ struct base_acl *acl;
+
+ acl = ACCESS_ONCE(inode->i_acl);
+ if (acl && IS_RICHACL(inode)) {
+ spin_lock(&inode->i_lock);
+ acl = inode->i_acl;
+ if (acl != ACL_NOT_CACHED)
+ base_acl_get(acl);
+ spin_unlock(&inode->i_lock);
+ }
+ return container_of(acl, struct richacl, a_base);
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl);
+
+struct richacl *get_cached_richacl_rcu(struct inode *inode)
+{
+ struct base_acl *acl = rcu_dereference(inode->i_acl);
+
+ return container_of(acl, struct richacl, a_base);
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl_rcu);
+
+void set_cached_richacl(struct inode *inode, struct richacl *acl)
+{
+ struct base_acl *old = NULL;
+
+ spin_lock(&inode->i_lock);
+ old = inode->i_acl;
+ rcu_assign_pointer(inode->i_acl, &richacl_get(acl)->a_base);
+ spin_unlock(&inode->i_lock);
+ if (old != ACL_NOT_CACHED)
+ base_acl_put(old);
+}
+EXPORT_SYMBOL_GPL(set_cached_richacl);
+
+void forget_cached_richacl(struct inode *inode)
+{
+ struct base_acl *old = NULL;
+
+ spin_lock(&inode->i_lock);
+ old = inode->i_acl;
+ inode->i_acl = ACL_NOT_CACHED;
+ spin_unlock(&inode->i_lock);
+ if (old != ACL_NOT_CACHED)
+ base_acl_put(old);
+}
+EXPORT_SYMBOL_GPL(forget_cached_richacl);
+
+struct richacl *get_richacl(struct inode *inode)
+{
+ struct richacl *acl;
+
+ acl = get_cached_richacl(inode);
+ if (acl != ACL_NOT_CACHED)
+ return acl;
+
+ if (!IS_RICHACL(inode))
+ return NULL;
+
+ /*
+ * A filesystem can force a ACL callback by just never filling the
+ * ACL cache. But normally you'd fill the cache either at inode
+ * instantiation time, or on the first ->get_richacl call.
+ *
+ * If the filesystem doesn't have a get_richacl() function at all,
+ * we'll just create the negative cache entry.
+ */
+ if (!inode->i_op->get_richacl) {
+ set_cached_richacl(inode, NULL);
+ return NULL;
+ }
+ return inode->i_op->get_richacl(inode);
+}
+EXPORT_SYMBOL_GPL(get_richacl);
+
/**
* richacl_permission - richacl permission check algorithm
* @inode: inode to check
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e04dbb4..560f4e0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -585,6 +585,7 @@ struct base_acl {
};
};
struct posix_acl;
+struct richacl;
#define ACL_NOT_CACHED ((void *)(-1))
#define IOP_FASTPERM 0x0001
@@ -603,9 +604,11 @@ struct inode {
kgid_t i_gid;
unsigned int i_flags;
-#if defined(CONFIG_FS_POSIX_ACL)
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
struct base_acl *i_acl;
+# if defined(CONFIG_FS_POSIX_ACL)
struct base_acl *i_default_acl;
+# endif
#endif
const struct inode_operations *i_op;
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 7628fad..7bf912b6 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -70,6 +70,12 @@ richacl_put(struct richacl *acl)
base_acl_put(&acl->a_base);
}
+extern struct richacl *get_cached_richacl(struct inode *);
+extern struct richacl *get_cached_richacl_rcu(struct inode *);
+extern void set_cached_richacl(struct inode *, struct richacl *);
+extern void forget_cached_richacl(struct inode *);
+extern struct richacl *get_richacl(struct inode *);
+
/**
* richace_is_owner - check if @ace is an OWNER@ entry
*/
--
2.4.3
From: "Aneesh Kumar K.V" <[email protected]>
This feature flag selects richacl instead of POSIX ACL support on the
filesystem. When this feature is off, the "acl" and "noacl" mount options
control whether POSIX ACLs are enabled. When it is on, richacls are
automatically enabled and using the "noacl" mount option leads to an error.
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
fs/ext4/ext4.h | 6 ++++--
fs/ext4/super.c | 49 ++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 44 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 157b458..44277f9 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1092,7 +1092,7 @@ struct ext4_inode_info {
#define EXT4_MOUNT_UPDATE_JOURNAL 0x01000 /* Update the journal format */
#define EXT4_MOUNT_NO_UID32 0x02000 /* Disable 32-bit UIDs */
#define EXT4_MOUNT_XATTR_USER 0x04000 /* Extended user attributes */
-#define EXT4_MOUNT_POSIX_ACL 0x08000 /* POSIX Access Control Lists */
+#define EXT4_MOUNT_ACL 0x08000 /* Access Control Lists */
#define EXT4_MOUNT_NO_AUTO_DA_ALLOC 0x10000 /* No auto delalloc mapping */
#define EXT4_MOUNT_BARRIER 0x20000 /* Use block barriers */
#define EXT4_MOUNT_QUOTA 0x80000 /* Some quota option set */
@@ -1690,6 +1690,7 @@ static inline int ext4_encrypted_inode(struct inode *inode)
#define EXT4_FEATURE_INCOMPAT_LARGEDIR 0x4000 /* >2GB or 3-lvl htree */
#define EXT4_FEATURE_INCOMPAT_INLINE_DATA 0x8000 /* data in inode */
#define EXT4_FEATURE_INCOMPAT_ENCRYPT 0x10000
+#define EXT4_FEATURE_INCOMPAT_RICHACL 0x20000
#define EXT4_FEATURE_COMPAT_FUNCS(name, flagname) \
static inline bool ext4_has_feature_##name(struct super_block *sb) \
@@ -1804,7 +1805,8 @@ EXT4_FEATURE_INCOMPAT_FUNCS(encrypt, ENCRYPT)
EXT4_FEATURE_INCOMPAT_MMP | \
EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
EXT4_FEATURE_INCOMPAT_ENCRYPT | \
- EXT4_FEATURE_INCOMPAT_CSUM_SEED)
+ EXT4_FEATURE_INCOMPAT_CSUM_SEED | \
+ EXT4_FEATURE_INCOMPAT_RICHACL)
#define EXT4_FEATURE_RO_COMPAT_SUPP (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3ed01ec..2ed8485 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1305,6 +1305,28 @@ static ext4_fsblk_t get_sb_block(void **data)
return sb_block;
}
+static int enable_acl(struct super_block *sb)
+{
+ sb->s_flags &= ~(MS_POSIXACL | MS_RICHACL);
+ if (test_opt(sb, ACL)) {
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+ EXT4_FEATURE_INCOMPAT_RICHACL)) {
+#ifdef CONFIG_EXT4_FS_RICHACL
+ sb->s_flags |= MS_RICHACL;
+#else
+ return -EOPNOTSUPP;
+#endif
+ } else {
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+ sb->s_flags |= MS_POSIXACL;
+#else
+ return -EOPNOTSUPP;
+#endif
+ }
+ }
+ return 0;
+}
+
#define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
"Contact [email protected] if you think we should keep it.\n";
@@ -1451,9 +1473,9 @@ static const struct mount_opts {
MOPT_NO_EXT2 | MOPT_DATAJ},
{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
- {Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
- {Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
+#if defined(CONFIG_EXT4_FS_POSIX_ACL) || defined(CONFIG_EXT4_FS_RICHACL)
+ {Opt_acl, EXT4_MOUNT_ACL, MOPT_SET},
+ {Opt_noacl, EXT4_MOUNT_ACL, MOPT_CLEAR},
#else
{Opt_acl, 0, MOPT_NOSUPPORT},
{Opt_noacl, 0, MOPT_NOSUPPORT},
@@ -1501,6 +1523,13 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
#endif
switch (token) {
case Opt_noacl:
+#ifdef CONFIG_EXT4_FS_RICHACL
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RICHACL)) {
+ ext4_msg(sb, KERN_ERR, "Mount option \"%s\" incompatible "
+ "with richacl feature", opt);
+ return -1;
+ }
+#endif
case Opt_nouser_xattr:
ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
break;
@@ -3267,8 +3296,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
set_opt(sb, NO_UID32);
/* xattr user namespace & acls are now defaulted on */
set_opt(sb, XATTR_USER);
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
- set_opt(sb, POSIX_ACL);
+#if defined(CONFIG_EXT4_FS_POSIX_ACL) || defined(CONFIG_EXT4_FS_RICHACL)
+ set_opt(sb, ACL);
#endif
/* don't forget to enable journal_csum when metadata_csum is enabled. */
if (ext4_has_metadata_csum(sb))
@@ -3351,8 +3380,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
sb->s_iflags |= SB_I_CGROUPWB;
}
- sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
- (test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
+ err = enable_acl(sb);
+ if (err)
+ goto failed_mount;
if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
(ext4_has_compat_features(sb) ||
@@ -4668,8 +4698,9 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
ext4_abort(sb, "Abort forced by user");
- sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
- (test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
+ err = enable_acl(sb);
+ if (err)
+ goto restore_opts;
es = sbi->s_es;
--
2.4.3
From: "Aneesh Kumar K.V" <[email protected]>
Support the richacl permission model in ext4. The richacls are stored
in "system.richacl" xattrs. Richacls need to be enabled by tune2fs or
at file system create time.
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
fs/ext4/Kconfig | 11 +++++
fs/ext4/Makefile | 1 +
fs/ext4/file.c | 3 ++
fs/ext4/ialloc.c | 11 ++++-
fs/ext4/inode.c | 12 ++++-
fs/ext4/namei.c | 5 ++
fs/ext4/richacl.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/richacl.h | 40 +++++++++++++++
fs/ext4/xattr.c | 7 +++
9 files changed, 229 insertions(+), 3 deletions(-)
create mode 100644 fs/ext4/richacl.c
create mode 100644 fs/ext4/richacl.h
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index b46e9fc..4e21c18 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -22,6 +22,17 @@ config EXT3_FS_POSIX_ACL
This config option is here only for backward compatibility. ext3
filesystem is now handled by the ext4 driver.
+config EXT4_FS_RICHACL
+ bool "Ext4 Rich Access Control Lists"
+ depends on EXT4_FS
+ select FS_RICHACL
+ help
+ Richacls are an implementation of NFSv4 ACLs, extended by file masks
+ to cleanly integrate into the POSIX file permission model. To learn
+ more about them, see http://www.bestbits.at/richacl/.
+
+ If you don't know what Richacls are, say N.
+
config EXT3_FS_SECURITY
bool "Ext3 Security Labels"
depends on EXT3_FS
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index f52cf54..1fb7f11 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -14,3 +14,4 @@ ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
ext4-$(CONFIG_EXT4_FS_ENCRYPTION) += crypto_policy.o crypto.o \
crypto_key.o crypto_fname.o
+ext4-$(CONFIG_EXT4_FS_RICHACL) += richacl.o
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 474f1a4..30bfc50 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -30,6 +30,7 @@
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
+#include "richacl.h"
/*
* Called when an inode is released. Note that this is different
@@ -764,6 +765,8 @@ const struct inode_operations ext4_file_inode_operations = {
.removexattr = generic_removexattr,
.get_acl = ext4_get_acl,
.set_acl = ext4_set_acl,
+ .get_richacl = ext4_get_richacl,
+ .set_richacl = ext4_set_richacl,
.fiemap = ext4_fiemap,
};
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index acc0ad5..f2d31c2 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -27,6 +27,7 @@
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
+#include "richacl.h"
#include <trace/events/ext4.h>
@@ -729,6 +730,14 @@ out:
return ret;
}
+static inline int
+ext4_new_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+ if (IS_RICHACL(dir))
+ return ext4_init_richacl(handle, inode, dir);
+ return ext4_init_acl(handle, inode, dir);
+}
+
/*
* There are two policies for allocating an inode. If the new inode is
* a directory, then a forward search is made for a block group with both
@@ -1093,7 +1102,7 @@ got:
if (err)
goto fail_drop;
- err = ext4_init_acl(handle, inode, dir);
+ err = ext4_new_acl(handle, inode, dir);
if (err)
goto fail_free_drop;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9cc57c3..ef6fb86 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -42,6 +42,7 @@
#include "xattr.h"
#include "acl.h"
#include "truncate.h"
+#include "richacl.h"
#include <trace/events/ext4.h>
@@ -4851,6 +4852,14 @@ static void ext4_wait_for_tail_page_commit(struct inode *inode)
}
}
+static inline int
+ext4_acl_chmod(struct inode *inode, umode_t mode)
+{
+ if (IS_RICHACL(inode))
+ return richacl_chmod(inode, inode->i_mode);
+ return posix_acl_chmod(inode, inode->i_mode);
+}
+
/*
* ext4_setattr()
*
@@ -5021,8 +5030,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
ext4_orphan_del(NULL, inode);
if (!rc && (ia_valid & ATTR_MODE))
- rc = posix_acl_chmod(inode, inode->i_mode);
-
+ rc = ext4_acl_chmod(inode, inode->i_mode);
err_out:
ext4_std_error(inode->i_sb, error);
if (!error)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 48e4b89..d86c5f2 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -38,6 +38,7 @@
#include "xattr.h"
#include "acl.h"
+#include "richacl.h"
#include <trace/events/ext4.h>
/*
@@ -3888,6 +3889,8 @@ const struct inode_operations ext4_dir_inode_operations = {
.removexattr = generic_removexattr,
.get_acl = ext4_get_acl,
.set_acl = ext4_set_acl,
+ .get_richacl = ext4_get_richacl,
+ .set_richacl = ext4_set_richacl,
.fiemap = ext4_fiemap,
};
@@ -3899,4 +3902,6 @@ const struct inode_operations ext4_special_inode_operations = {
.removexattr = generic_removexattr,
.get_acl = ext4_get_acl,
.set_acl = ext4_set_acl,
+ .get_richacl = ext4_get_richacl,
+ .set_richacl = ext4_set_richacl,
};
diff --git a/fs/ext4/richacl.c b/fs/ext4/richacl.c
new file mode 100644
index 0000000..d581be4
--- /dev/null
+++ b/fs/ext4/richacl.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Author: Aneesh Kumar K.V <[email protected]>,
+ * Andreas Gruenbacher <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/richacl_xattr.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "richacl.h"
+
+struct richacl *
+ext4_get_richacl(struct inode *inode)
+{
+ const int name_index = EXT4_XATTR_INDEX_RICHACL;
+ void *value = NULL;
+ struct richacl *acl = NULL;
+ int retval;
+
+ retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
+ if (retval > 0) {
+ value = kmalloc(retval, GFP_NOFS);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ retval = ext4_xattr_get(inode, name_index, "", value, retval);
+ }
+ if (retval > 0) {
+ acl = richacl_from_xattr(&init_user_ns, value, retval);
+ if (acl == ERR_PTR(-EINVAL))
+ acl = ERR_PTR(-EIO);
+ } else if (retval != -ENODATA && retval != -ENOSYS) {
+ acl = ERR_PTR(retval);
+ }
+ kfree(value);
+
+ if (!IS_ERR(acl))
+ set_cached_richacl(inode, acl);
+
+ return acl;
+}
+
+static int
+__ext4_remove_richacl(handle_t *handle, struct inode *inode)
+{
+ const int name_index = EXT4_XATTR_INDEX_RICHACL;
+ int retval;
+
+ retval = ext4_xattr_set_handle(handle, inode, name_index, "",
+ NULL, 0, 0);
+ if (!retval)
+ set_cached_richacl(inode, NULL);
+ return retval;
+}
+
+static int
+__ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
+{
+ const int name_index = EXT4_XATTR_INDEX_RICHACL;
+ umode_t mode = inode->i_mode;
+ int retval, size;
+ void *value;
+
+ if (richacl_equiv_mode(acl, &mode) == 0) {
+ inode->i_ctime = ext4_current_time(inode);
+ inode->i_mode = mode;
+ ext4_mark_inode_dirty(handle, inode);
+ return __ext4_remove_richacl(handle, inode);
+ }
+
+ mode &= ~S_IRWXUGO;
+ mode |= richacl_masks_to_mode(acl);
+
+ size = richacl_xattr_size(acl);
+ value = kmalloc(size, GFP_NOFS);
+ if (!value)
+ return -ENOMEM;
+ richacl_to_xattr(&init_user_ns, acl, value, size);
+ inode->i_mode = mode;
+ retval = ext4_xattr_set_handle(handle, inode, name_index, "",
+ value, size, 0);
+ kfree(value);
+ if (retval)
+ return retval;
+
+ set_cached_richacl(inode, acl);
+
+ return 0;
+}
+
+int
+ext4_set_richacl(struct inode *inode, struct richacl *acl)
+{
+ handle_t *handle;
+ int retval, retries = 0;
+
+retry:
+ handle = ext4_journal_start(inode, EXT4_HT_XATTR,
+ ext4_jbd2_credits_xattr(inode));
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ if (acl)
+ retval = __ext4_set_richacl(handle, inode, acl);
+ else
+ retval = __ext4_remove_richacl(handle, inode);
+
+ ext4_journal_stop(handle);
+ if (retval == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+ return retval;
+}
+
+int
+ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+ struct richacl *acl = richacl_create(&inode->i_mode, dir);
+ int error;
+
+ error = PTR_ERR(acl);
+ if (IS_ERR(acl))
+ return error;
+ if (acl) {
+ error = __ext4_set_richacl(handle, inode, acl);
+ richacl_put(acl);
+ }
+ return error;
+}
diff --git a/fs/ext4/richacl.h b/fs/ext4/richacl.h
new file mode 100644
index 0000000..6fe9a92
--- /dev/null
+++ b/fs/ext4/richacl.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Author Aneesh Kumar K.V <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#ifndef __FS_EXT4_RICHACL_H
+#define __FS_EXT4_RICHACL_H
+
+#include <linux/richacl.h>
+
+#ifdef CONFIG_EXT4_FS_RICHACL
+
+extern struct richacl *ext4_get_richacl(struct inode *);
+extern int ext4_set_richacl(struct inode *, struct richacl *);
+
+extern int ext4_init_richacl(handle_t *, struct inode *, struct inode *);
+
+#else /* CONFIG_EXT4_FS_RICHACL */
+
+#define ext4_get_richacl NULL
+#define ext4_set_richacl NULL
+
+static inline int
+ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+ return 0;
+}
+
+#endif /* CONFIG_EXT4_FS_RICHACL */
+#endif /* __FS_EXT4_RICHACL_H */
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index a95151e..ef76630 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -55,6 +55,7 @@
#include <linux/slab.h>
#include <linux/mbcache.h>
#include <linux/quotaops.h>
+#include <linux/richacl_xattr.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
@@ -97,6 +98,9 @@ static const struct xattr_handler *ext4_xattr_handler_map[] = {
#ifdef CONFIG_EXT4_FS_SECURITY
[EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
#endif
+#ifdef CONFIG_EXT4_FS_RICHACL
+ [EXT4_XATTR_INDEX_RICHACL] = &richacl_xattr_handler,
+#endif
};
const struct xattr_handler *ext4_xattr_handlers[] = {
@@ -109,6 +113,9 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
#ifdef CONFIG_EXT4_FS_SECURITY
&ext4_xattr_security_handler,
#endif
+#ifdef CONFIG_EXT4_FS_RICHACL
+ &richacl_xattr_handler,
+#endif
NULL
};
--
2.4.3
Add richacl xattr handler implementing the xattr operations based on the
get_richacl and set_richacl inode operations.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/richacl_xattr.c | 73 +++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl_xattr.h | 2 ++
2 files changed, 75 insertions(+)
diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
index a273139..afa2859 100644
--- a/fs/richacl_xattr.c
+++ b/fs/richacl_xattr.c
@@ -18,7 +18,9 @@
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/xattr.h>
#include <linux/richacl_xattr.h>
+#include <uapi/linux/xattr.h>
MODULE_LICENSE("GPL");
@@ -160,3 +162,74 @@ richacl_to_xattr(struct user_namespace *user_ns,
return real_size;
}
EXPORT_SYMBOL_GPL(richacl_to_xattr);
+
+static bool
+richacl_xattr_list(struct dentry *dentry)
+{
+ return IS_RICHACL(d_backing_inode(dentry));
+}
+
+static int
+richacl_xattr_get(const struct xattr_handler *handler,
+ struct dentry *dentry, const char *name, void *buffer,
+ size_t buffer_size)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct richacl *acl;
+ int error;
+
+ if (*name)
+ return -EINVAL;
+ if (!IS_RICHACL(inode))
+ return -EOPNOTSUPP;
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+ acl = get_richacl(inode);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl == NULL)
+ return -ENODATA;
+ error = richacl_to_xattr(current_user_ns(), acl, buffer, buffer_size);
+ richacl_put(acl);
+ return error;
+}
+
+static int
+richacl_xattr_set(const struct xattr_handler *handler,
+ struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct richacl *acl = NULL;
+ int ret;
+
+ if (*name)
+ return -EINVAL;
+ if (!IS_RICHACL(inode))
+ return -EOPNOTSUPP;
+ if (!inode->i_op->set_richacl)
+ return -EOPNOTSUPP;
+
+ if (!uid_eq(current_fsuid(), inode->i_uid) &&
+ inode_permission(inode, MAY_CHMOD) &&
+ !capable(CAP_FOWNER))
+ return -EPERM;
+
+ if (value) {
+ acl = richacl_from_xattr(current_user_ns(), value, size);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ }
+
+ ret = inode->i_op->set_richacl(inode, acl);
+ richacl_put(acl);
+ return ret;
+}
+
+struct xattr_handler richacl_xattr_handler = {
+ .name = XATTR_NAME_RICHACL,
+ .list = richacl_xattr_list,
+ .get = richacl_xattr_get,
+ .set = richacl_xattr_set,
+};
+EXPORT_SYMBOL(richacl_xattr_handler);
diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
index ab67af2..ad4a56e 100644
--- a/include/linux/richacl_xattr.h
+++ b/include/linux/richacl_xattr.h
@@ -26,4 +26,6 @@ extern size_t richacl_xattr_size(const struct richacl *);
extern int richacl_to_xattr(struct user_namespace *, const struct richacl *,
void *, size_t);
+extern struct xattr_handler richacl_xattr_handler;
+
#endif /* __RICHACL_XATTR_H */
--
2.4.3
Hook the richacl permission checking function into the vfs.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/namei.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
fs/posix_acl.c | 6 +++---
2 files changed, 52 insertions(+), 5 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 59b1da0..716c01d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -35,6 +35,7 @@
#include <linux/fs_struct.h>
#include <linux/posix_acl.h>
#include <linux/hash.h>
+#include <linux/richacl.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -255,7 +256,40 @@ void putname(struct filename *name)
__putname(name);
}
-static int check_acl(struct inode *inode, int mask)
+static int check_richacl(struct inode *inode, int mask)
+{
+#ifdef CONFIG_FS_RICHACL
+ struct richacl *acl;
+
+ if (mask & MAY_NOT_BLOCK) {
+ acl = get_cached_richacl_rcu(inode);
+ if (!acl)
+ goto no_acl;
+ /* no ->get_richacl() calls in RCU mode... */
+ if (acl == ACL_NOT_CACHED)
+ return -ECHILD;
+ return richacl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
+ }
+
+ acl = get_richacl(inode);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl) {
+ int error = richacl_permission(inode, acl, mask);
+ richacl_put(acl);
+ return error;
+ }
+no_acl:
+#endif
+ if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP |
+ MAY_CHMOD | MAY_SET_TIMES)) {
+ /* File permission bits cannot grant this. */
+ return -EACCES;
+ }
+ return -EAGAIN;
+}
+
+static int check_posix_acl(struct inode *inode, int mask)
{
#ifdef CONFIG_FS_POSIX_ACL
struct posix_acl *acl;
@@ -290,11 +324,24 @@ static int acl_permission_check(struct inode *inode, int mask)
{
unsigned int mode = inode->i_mode;
+ /*
+ * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner
+ * permissions, and we can skip checking posix acls for the owner.
+ * With richacls, the owner may be granted fewer permissions than the
+ * mode bits seem to suggest (for example, append but not write), and
+ * we always need to check the richacl.
+ */
+
+ if (IS_RICHACL(inode)) {
+ int error = check_richacl(inode, mask);
+ if (error != -EAGAIN)
+ return error;
+ }
if (likely(uid_eq(current_fsuid(), inode->i_uid)))
mode >>= 6;
else {
if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
- int error = check_acl(inode, mask);
+ int error = check_posix_acl(inode, mask);
if (error != -EAGAIN)
return error;
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index f24646e..7810c6f 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -100,13 +100,13 @@ struct posix_acl *get_acl(struct inode *inode, int type)
{
struct posix_acl *acl;
+ if (!IS_POSIXACL(inode))
+ return NULL;
+
acl = get_cached_acl(inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
- if (!IS_POSIXACL(inode))
- return NULL;
-
/*
* A filesystem can force a ACL callback by just never filling the
* ACL cache. But normally you'd fill the cache either at inode
--
2.4.3
Map between "system.richacl" xattrs and the in-kernel representation.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/Makefile | 2 +-
fs/richacl_xattr.c | 162 +++++++++++++++++++++++++++++++++++++
fs/xattr.c | 29 +++++--
include/linux/richacl_xattr.h | 29 +++++++
include/uapi/linux/Kbuild | 1 +
include/uapi/linux/richacl_xattr.h | 44 ++++++++++
include/uapi/linux/xattr.h | 2 +
7 files changed, 262 insertions(+), 7 deletions(-)
create mode 100644 fs/richacl_xattr.c
create mode 100644 include/linux/richacl_xattr.h
create mode 100644 include/uapi/linux/richacl_xattr.h
diff --git a/fs/Makefile b/fs/Makefile
index d5b45ca..2d6d224 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -49,7 +49,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o
obj-$(CONFIG_FHANDLE) += fhandle.o
obj-$(CONFIG_FS_RICHACL) += richacl.o
-richacl-y := richacl_base.o richacl_inode.o
+richacl-y := richacl_base.o richacl_inode.o richacl_xattr.o
obj-y += quota/
diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
new file mode 100644
index 0000000..a273139
--- /dev/null
+++ b/fs/richacl_xattr.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2006, 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/richacl_xattr.h>
+
+MODULE_LICENSE("GPL");
+
+/**
+ * richacl_from_xattr - convert a richacl xattr into the in-memory representation
+ */
+struct richacl *
+richacl_from_xattr(struct user_namespace *user_ns,
+ const void *value, size_t size)
+{
+ const struct richacl_xattr *xattr_acl = value;
+ const struct richace_xattr *xattr_ace = (void *)(xattr_acl + 1);
+ struct richacl *acl;
+ struct richace *ace;
+ int count;
+
+ if (size < sizeof(*xattr_acl) ||
+ xattr_acl->a_version != RICHACL_XATTR_VERSION ||
+ (xattr_acl->a_flags & ~RICHACL_VALID_FLAGS))
+ return ERR_PTR(-EINVAL);
+ size -= sizeof(*xattr_acl);
+ count = le16_to_cpu(xattr_acl->a_count);
+ if (count > RICHACL_XATTR_MAX_COUNT)
+ return ERR_PTR(-EINVAL);
+ if (size != count * sizeof(*xattr_ace))
+ return ERR_PTR(-EINVAL);
+
+ acl = richacl_alloc(count, GFP_NOFS);
+ if (!acl)
+ return ERR_PTR(-ENOMEM);
+
+ acl->a_flags = xattr_acl->a_flags;
+ acl->a_owner_mask = le32_to_cpu(xattr_acl->a_owner_mask);
+ if (acl->a_owner_mask & ~RICHACE_VALID_MASK)
+ goto fail_einval;
+ acl->a_group_mask = le32_to_cpu(xattr_acl->a_group_mask);
+ if (acl->a_group_mask & ~RICHACE_VALID_MASK)
+ goto fail_einval;
+ acl->a_other_mask = le32_to_cpu(xattr_acl->a_other_mask);
+ if (acl->a_other_mask & ~RICHACE_VALID_MASK)
+ goto fail_einval;
+
+ richacl_for_each_entry(ace, acl) {
+ ace->e_type = le16_to_cpu(xattr_ace->e_type);
+ ace->e_flags = le16_to_cpu(xattr_ace->e_flags);
+ ace->e_mask = le32_to_cpu(xattr_ace->e_mask);
+
+ if (ace->e_flags & ~RICHACE_VALID_FLAGS)
+ goto fail_einval;
+ if (ace->e_flags & RICHACE_SPECIAL_WHO) {
+ ace->e_id.special = le32_to_cpu(xattr_ace->e_id);
+ if (ace->e_id.special > RICHACE_EVERYONE_SPECIAL_ID)
+ goto fail_einval;
+ } else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP) {
+ u32 id = le32_to_cpu(xattr_ace->e_id);
+
+ ace->e_id.gid = make_kgid(user_ns, id);
+ if (!gid_valid(ace->e_id.gid))
+ goto fail_einval;
+ } else {
+ u32 id = le32_to_cpu(xattr_ace->e_id);
+
+ ace->e_id.uid = make_kuid(user_ns, id);
+ if (!uid_valid(ace->e_id.uid))
+ goto fail_einval;
+ }
+ if (ace->e_type > RICHACE_ACCESS_DENIED_ACE_TYPE ||
+ (ace->e_mask & ~RICHACE_VALID_MASK))
+ goto fail_einval;
+
+ xattr_ace++;
+ }
+
+ return acl;
+
+fail_einval:
+ richacl_put(acl);
+ return ERR_PTR(-EINVAL);
+}
+EXPORT_SYMBOL_GPL(richacl_from_xattr);
+
+/**
+ * richacl_xattr_size - compute the size of the xattr representation of @acl
+ */
+size_t
+richacl_xattr_size(const struct richacl *acl)
+{
+ size_t size = sizeof(struct richacl_xattr);
+
+ size += sizeof(struct richace_xattr) * acl->a_count;
+ return size;
+}
+EXPORT_SYMBOL_GPL(richacl_xattr_size);
+
+/**
+ * richacl_to_xattr - convert @acl into its xattr representation
+ * @acl: the richacl to convert
+ * @buffer: buffer for the result
+ * @size: size of @buffer
+ */
+int
+richacl_to_xattr(struct user_namespace *user_ns,
+ const struct richacl *acl, void *buffer, size_t size)
+{
+ struct richacl_xattr *xattr_acl = buffer;
+ struct richace_xattr *xattr_ace;
+ const struct richace *ace;
+ size_t real_size;
+
+ real_size = richacl_xattr_size(acl);
+ if (!buffer)
+ return real_size;
+ if (real_size > size)
+ return -ERANGE;
+
+ xattr_acl->a_version = RICHACL_XATTR_VERSION;
+ xattr_acl->a_flags = acl->a_flags;
+ xattr_acl->a_count = cpu_to_le16(acl->a_count);
+
+ xattr_acl->a_owner_mask = cpu_to_le32(acl->a_owner_mask);
+ xattr_acl->a_group_mask = cpu_to_le32(acl->a_group_mask);
+ xattr_acl->a_other_mask = cpu_to_le32(acl->a_other_mask);
+
+ xattr_ace = (void *)(xattr_acl + 1);
+ richacl_for_each_entry(ace, acl) {
+ xattr_ace->e_type = cpu_to_le16(ace->e_type);
+ xattr_ace->e_flags = cpu_to_le16(ace->e_flags);
+ xattr_ace->e_mask = cpu_to_le32(ace->e_mask);
+ if (ace->e_flags & RICHACE_SPECIAL_WHO)
+ xattr_ace->e_id = cpu_to_le32(ace->e_id.special);
+ else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP)
+ xattr_ace->e_id =
+ cpu_to_le32(from_kgid(user_ns, ace->e_id.gid));
+ else
+ xattr_ace->e_id =
+ cpu_to_le32(from_kuid(user_ns, ace->e_id.uid));
+ xattr_ace++;
+ }
+ return real_size;
+}
+EXPORT_SYMBOL_GPL(richacl_to_xattr);
diff --git a/fs/xattr.c b/fs/xattr.c
index 07d0e47..d29e067 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -295,6 +295,16 @@ out:
}
EXPORT_SYMBOL_GPL(vfs_removexattr);
+static void
+fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
+{
+ if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return;
+ kname += XATTR_SYSTEM_PREFIX_LEN;
+ if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+ !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+ posix_acl_fix_xattr_from_user(kvalue, size);
+}
/*
* Extended attribute SET operations
@@ -329,9 +339,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
error = -EFAULT;
goto out;
}
- if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
- (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
- posix_acl_fix_xattr_from_user(kvalue, size);
+ fix_xattr_from_user(kname, kvalue, size);
}
error = vfs_setxattr(d, kname, kvalue, size, flags);
@@ -396,6 +404,17 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
return error;
}
+static void
+fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
+{
+ if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return;
+ kname += XATTR_SYSTEM_PREFIX_LEN;
+ if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+ !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+ posix_acl_fix_xattr_to_user(kvalue, size);
+}
+
/*
* Extended attribute GET operations
*/
@@ -426,9 +445,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
error = vfs_getxattr(d, kname, kvalue, size);
if (error > 0) {
- if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
- (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
- posix_acl_fix_xattr_to_user(kvalue, size);
+ fix_xattr_to_user(kname, kvalue, size);
if (size && copy_to_user(value, kvalue, error))
error = -EFAULT;
} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
new file mode 100644
index 0000000..ab67af2
--- /dev/null
+++ b/include/linux/richacl_xattr.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2006, 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __RICHACL_XATTR_H
+#define __RICHACL_XATTR_H
+
+#include <uapi/linux/richacl_xattr.h>
+#include <linux/richacl.h>
+
+extern struct richacl *richacl_from_xattr(struct user_namespace *, const void *,
+ size_t);
+extern size_t richacl_xattr_size(const struct richacl *);
+extern int richacl_to_xattr(struct user_namespace *, const struct richacl *,
+ void *, size_t);
+
+#endif /* __RICHACL_XATTR_H */
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 6e05dc8..14b8a06 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -352,6 +352,7 @@ header-y += reiserfs_fs.h
header-y += reiserfs_xattr.h
header-y += resource.h
header-y += richacl.h
+header-y += richacl_xattr.h
header-y += rfkill.h
header-y += romfs_fs.h
header-y += rose.h
diff --git a/include/uapi/linux/richacl_xattr.h b/include/uapi/linux/richacl_xattr.h
new file mode 100644
index 0000000..5178ca6
--- /dev/null
+++ b/include/uapi/linux/richacl_xattr.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2006, 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#ifndef __UAPI_RICHACL_XATTR_H
+#define __UAPI_RICHACL_XATTR_H
+
+#include <linux/types.h>
+#include <linux/limits.h>
+
+struct richace_xattr {
+ __le16 e_type;
+ __le16 e_flags;
+ __le32 e_mask;
+ __le32 e_id;
+};
+
+struct richacl_xattr {
+ unsigned char a_version;
+ unsigned char a_flags;
+ __le16 a_count;
+ __le32 a_owner_mask;
+ __le32 a_group_mask;
+ __le32 a_other_mask;
+};
+
+#define RICHACL_XATTR_VERSION 0
+#define RICHACL_XATTR_MAX_COUNT \
+ ((XATTR_SIZE_MAX - sizeof(struct richacl_xattr)) / \
+ sizeof(struct richace_xattr))
+
+#endif /* __UAPI_RICHACL_XATTR_H */
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index 1590c49..1996903 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -73,5 +73,7 @@
#define XATTR_POSIX_ACL_DEFAULT "posix_acl_default"
#define XATTR_NAME_POSIX_ACL_DEFAULT XATTR_SYSTEM_PREFIX XATTR_POSIX_ACL_DEFAULT
+#define XATTR_RICHACL "richacl"
+#define XATTR_NAME_RICHACL XATTR_SYSTEM_PREFIX XATTR_RICHACL
#endif /* _UAPI_LINUX_XATTR_H */
--
2.4.3
When a new file is created, it can inherit an acl from its parent
directory; this is similar to how default acls work in POSIX ACLs.
As with POSIX ACLs, if a file inherits an acl from its parent directory,
the intersection between the create mode and the permissions granted by
the inherited acl determines the file masks and file permission bits,
and the umask is ignored.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/richacl_base.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/richacl_inode.c | 70 ++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 2 ++
3 files changed, 153 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 74e5cb5..58dffca 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -486,3 +486,84 @@ richacl_equiv_mode(const struct richacl *acl, umode_t *mode_p)
return 0;
}
EXPORT_SYMBOL_GPL(richacl_equiv_mode);
+
+static inline bool
+ace_inherits_to_directory(const struct richace *ace)
+{
+ if (ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE)
+ return true;
+ if ((ace->e_flags & RICHACE_FILE_INHERIT_ACE) &&
+ !(ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE))
+ return true;
+ return false;
+}
+
+/**
+ * richacl_inherit - compute the inherited acl of a new file
+ * @dir_acl: acl of the containing directory
+ * @isdir: inherit by a directory or non-directory?
+ *
+ * A directory can have acl entries which files and/or directories created
+ * inside the directory will inherit. This function computes the acl for such
+ * a new file. If there is no inheritable acl, it will return %NULL.
+ */
+struct richacl *
+richacl_inherit(const struct richacl *dir_acl, int isdir)
+{
+ const struct richace *dir_ace;
+ struct richacl *acl = NULL;
+ struct richace *ace;
+ int count = 0;
+
+ if (isdir) {
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!ace_inherits_to_directory(dir_ace))
+ continue;
+ count++;
+ }
+ if (!count)
+ return NULL;
+ acl = richacl_alloc(count, GFP_KERNEL);
+ if (!acl)
+ return ERR_PTR(-ENOMEM);
+ ace = acl->a_entries;
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!ace_inherits_to_directory(dir_ace))
+ continue;
+ richace_copy(ace, dir_ace);
+ if (dir_ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE)
+ ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS;
+ else if (dir_ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE)
+ ace->e_flags &= ~RICHACE_INHERIT_ONLY_ACE;
+ else
+ ace->e_flags |= RICHACE_INHERIT_ONLY_ACE;
+ ace++;
+ }
+ } else {
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
+ continue;
+ count++;
+ }
+ if (!count)
+ return NULL;
+ acl = richacl_alloc(count, GFP_KERNEL);
+ if (!acl)
+ return ERR_PTR(-ENOMEM);
+ ace = acl->a_entries;
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
+ continue;
+ richace_copy(ace, dir_ace);
+ ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS;
+ /*
+ * RICHACE_DELETE_CHILD is meaningless for
+ * non-directories, so clear it.
+ */
+ ace->e_mask &= ~RICHACE_DELETE_CHILD;
+ ace++;
+ }
+ }
+
+ return acl;
+}
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index e329826..ec3d2c8 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -254,3 +254,73 @@ richacl_chmod(struct inode *inode, umode_t mode)
return retval;
}
EXPORT_SYMBOL(richacl_chmod);
+
+/*
+ * richacl_inherit_inode - compute inherited acl and file mode
+ * @dir_acl: acl of the containing directory
+ * @mode_p: mode of the new inode
+ *
+ * The file permission bits in @mode_p must be set to the create mode by the
+ * caller.
+ *
+ * If there is an inheritable acl, the maximum permissions that the acl grants
+ * are computed and the file masks of the new acl are set accordingly.
+ */
+static struct richacl *
+richacl_inherit_inode(const struct richacl *dir_acl, umode_t *mode_p)
+{
+ struct richacl *acl;
+ umode_t mode = *mode_p;
+
+ acl = richacl_inherit(dir_acl, S_ISDIR(mode));
+ if (acl) {
+ if (richacl_equiv_mode(acl, &mode) == 0) {
+ *mode_p &= mode;
+ richacl_put(acl);
+ acl = NULL;
+ } else {
+ richacl_compute_max_masks(acl);
+ /*
+ * Ensure that the acl will not grant any permissions
+ * beyond the create mode.
+ */
+ acl->a_flags |= RICHACL_MASKED;
+ acl->a_owner_mask &=
+ richacl_mode_to_mask(mode >> 6);
+ acl->a_group_mask &=
+ richacl_mode_to_mask(mode >> 3);
+ acl->a_other_mask &=
+ richacl_mode_to_mask(mode);
+ }
+ } else
+ *mode_p &= ~current_umask();
+
+ return acl;
+}
+
+/**
+ * richacl_create - filesystem create helper
+ * @mode_p: mode of the new inode
+ * @dir: containing directory
+ *
+ * Compute the inherited acl for a new inode. If there is no acl to inherit,
+ * apply the umask. Use when creating a new inode on a richacl enabled file
+ * system.
+ */
+struct richacl *richacl_create(umode_t *mode_p, struct inode *dir)
+{
+ struct richacl *dir_acl, *acl = NULL;
+
+ if (S_ISLNK(*mode_p))
+ return NULL;
+ dir_acl = get_richacl(dir);
+ if (dir_acl) {
+ if (IS_ERR(dir_acl))
+ return dir_acl;
+ acl = richacl_inherit_inode(dir_acl, mode_p);
+ richacl_put(dir_acl);
+ } else
+ *mode_p &= ~current_umask();
+ return acl;
+}
+EXPORT_SYMBOL_GPL(richacl_create);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index b7128bf..c8fae91a 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -186,9 +186,11 @@ extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
extern struct richacl *__richacl_chmod(struct richacl *, umode_t);
extern int richacl_equiv_mode(const struct richacl *, umode_t *);
+extern struct richacl *richacl_inherit(const struct richacl *, int);
/* richacl_inode.c */
extern int richacl_permission(struct inode *, const struct richacl *, int);
extern int richacl_chmod(struct inode *, umode_t);
+extern struct richacl *richacl_create(umode_t *, struct inode *);
#endif /* __RICHACL_H */
--
2.4.3
Automatic Inheritance (AI) allows changes to the acl of a directory to
propagate down to children.
This is mostly implemented in user space: when a process changes the
permissions of a directory and Automatic Inheritance is enabled for that
directory, the process must propagate those changes to all children,
recursively.
The kernel enables this by keeping track of which permissions have been
inherited at create time. In addition, it makes sure that permission
propagation is turned off when the permissions are set explicitly (for
example, upon create or chmod).
Automatic Inheritance works as follows:
- When the RICHACL_AUTO_INHERIT flag in the acl of a file or directory
is not set, the file or directory is not affected by AI.
- When the RICHACL_AUTO_INHERIT flag in the acl of a directory is set
and a file or subdirectory is created in that directory, the
inherited acl will have the RICHACL_AUTO_INHERIT flag set, and all
inherited aces will have the RICHACE_INHERITED_ACE flag set. This
allows user space to distinguish between aces which have been
inherited and aces which have been explicitly added.
- When the RICHACL_PROTECTED acl flag in the acl of a file or directory
is set, AI will not modify the acl. This does not affect propagation
of permissions from the file to its children (if the file is a
directory).
Linux does not have a way of creating files or directories without setting the
file permission bits, so all files created inside a directory with
RICHACL_AUTO_INHERIT set will have the RICHACL_PROTECTED flag set. This
effectively disables Automatic Inheritance.
Protocols which support creating files without specifying permissions can
explicitly clear the RICHACL_PROTECTED flag after creating a file and reset the
file masks to "undo" applying the create mode; see richacl_compute_max_masks().
They should set the RICHACL_DEFAULTED flag. (A mechanism that would allow to
indicate to the kernel to ignore the create mode in the first place when there
are inherited permissions would be nice to have.)
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/richacl_base.c | 13 ++++++++++++-
fs/richacl_inode.c | 7 +++++++
include/linux/richacl.h | 12 ++++++++++++
include/uapi/linux/richacl.h | 11 ++++++++++-
4 files changed, 41 insertions(+), 2 deletions(-)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 58dffca..cad6171 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -366,7 +366,8 @@ __richacl_chmod(struct richacl *acl, umode_t mode)
acl->a_group_mask == group_mask &&
acl->a_other_mask == other_mask &&
(acl->a_flags & RICHACL_MASKED) &&
- (acl->a_flags & RICHACL_WRITE_THROUGH))
+ (acl->a_flags & RICHACL_WRITE_THROUGH) &&
+ (!richacl_is_auto_inherit(acl) || richacl_is_protected(acl)))
return acl;
clone = richacl_clone(acl, GFP_KERNEL);
@@ -378,6 +379,8 @@ __richacl_chmod(struct richacl *acl, umode_t mode)
clone->a_owner_mask = owner_mask;
clone->a_group_mask = group_mask;
clone->a_other_mask = other_mask;
+ if (richacl_is_auto_inherit(clone))
+ clone->a_flags |= RICHACL_PROTECTED;
return clone;
}
@@ -564,6 +567,14 @@ richacl_inherit(const struct richacl *dir_acl, int isdir)
ace++;
}
}
+ if (richacl_is_auto_inherit(dir_acl)) {
+ acl->a_flags = RICHACL_AUTO_INHERIT;
+ richacl_for_each_entry(ace, acl)
+ ace->e_flags |= RICHACE_INHERITED_ACE;
+ } else {
+ richacl_for_each_entry(ace, acl)
+ ace->e_flags &= ~RICHACE_INHERITED_ACE;
+ }
return acl;
}
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index ec3d2c8..99a1ab6 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -279,6 +279,13 @@ richacl_inherit_inode(const struct richacl *dir_acl, umode_t *mode_p)
richacl_put(acl);
acl = NULL;
} else {
+ /*
+ * We need to set RICHACL_PROTECTED because we are
+ * doing an implicit chmod
+ */
+ if (richacl_is_auto_inherit(acl))
+ acl->a_flags |= RICHACL_PROTECTED;
+
richacl_compute_max_masks(acl);
/*
* Ensure that the acl will not grant any permissions
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index c8fae91a..c524a4b 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -76,6 +76,18 @@ extern void set_cached_richacl(struct inode *, struct richacl *);
extern void forget_cached_richacl(struct inode *);
extern struct richacl *get_richacl(struct inode *);
+static inline int
+richacl_is_auto_inherit(const struct richacl *acl)
+{
+ return acl->a_flags & RICHACL_AUTO_INHERIT;
+}
+
+static inline int
+richacl_is_protected(const struct richacl *acl)
+{
+ return acl->a_flags & RICHACL_PROTECTED;
+}
+
/**
* richace_is_owner - check if @ace is an OWNER@ entry
*/
diff --git a/include/uapi/linux/richacl.h b/include/uapi/linux/richacl.h
index 1ed48ac..8849a53 100644
--- a/include/uapi/linux/richacl.h
+++ b/include/uapi/linux/richacl.h
@@ -18,6 +18,9 @@
#define __UAPI_RICHACL_H
/* a_flags values */
+#define RICHACL_AUTO_INHERIT 0x01
+#define RICHACL_PROTECTED 0x02
+#define RICHACL_DEFAULTED 0x04
#define RICHACL_WRITE_THROUGH 0x40
#define RICHACL_MASKED 0x80
@@ -31,6 +34,7 @@
#define RICHACE_NO_PROPAGATE_INHERIT_ACE 0x0004
#define RICHACE_INHERIT_ONLY_ACE 0x0008
#define RICHACE_IDENTIFIER_GROUP 0x0040
+#define RICHACE_INHERITED_ACE 0x0080
#define RICHACE_SPECIAL_WHO 0x4000
/* e_mask bitflags */
@@ -60,6 +64,9 @@
#define RICHACE_EVERYONE_SPECIAL_ID 2
#define RICHACL_VALID_FLAGS ( \
+ RICHACL_AUTO_INHERIT | \
+ RICHACL_PROTECTED | \
+ RICHACL_DEFAULTED | \
RICHACL_WRITE_THROUGH | \
RICHACL_MASKED )
@@ -69,13 +76,15 @@
RICHACE_NO_PROPAGATE_INHERIT_ACE | \
RICHACE_INHERIT_ONLY_ACE | \
RICHACE_IDENTIFIER_GROUP | \
+ RICHACE_INHERITED_ACE | \
RICHACE_SPECIAL_WHO )
#define RICHACE_INHERITANCE_FLAGS ( \
RICHACE_FILE_INHERIT_ACE | \
RICHACE_DIRECTORY_INHERIT_ACE | \
RICHACE_NO_PROPAGATE_INHERIT_ACE | \
- RICHACE_INHERIT_ONLY_ACE )
+ RICHACE_INHERIT_ONLY_ACE | \
+ RICHACE_INHERITED_ACE )
/* Valid RICHACE_* flags for directories and non-directories */
#define RICHACE_VALID_MASK ( \
--
2.4.3
ACLs are considered equivalent to file modes if they only consist of
owner@, group@, and everyone@ entries, the owner@ permissions do not
depend on whether the owner is a member in the owning group, and no
inheritance flags are set. This test is used to avoid storing richacls
if the acl can be computed from the file permission bits.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/richacl_base.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 1 +
2 files changed, 105 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index e4dd779..74e5cb5 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -382,3 +382,107 @@ __richacl_chmod(struct richacl *acl, umode_t mode)
return clone;
}
EXPORT_SYMBOL_GPL(__richacl_chmod);
+
+/**
+ * richacl_equiv_mode - compute the mode equivalent of @acl
+ *
+ * An acl is considered equivalent to a file mode if it only consists of
+ * owner@, group@, and everyone@ entries and the owner@ permissions do not
+ * depend on whether the owner is a member in the owning group.
+ */
+int
+richacl_equiv_mode(const struct richacl *acl, umode_t *mode_p)
+{
+ umode_t mode = *mode_p;
+
+ /*
+ * The RICHACE_DELETE_CHILD flag is meaningless for non-directories, so
+ * we ignore it.
+ */
+ unsigned int x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD;
+ struct {
+ unsigned int allowed;
+ unsigned int defined; /* allowed or denied */
+ } owner = {
+ .defined = RICHACE_POSIX_ALWAYS_ALLOWED |
+ RICHACE_POSIX_OWNER_ALLOWED | x,
+ }, group = {
+ .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x,
+ }, everyone = {
+ .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x,
+ };
+ const struct richace *ace;
+
+ if (acl->a_flags & ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED))
+ return -1;
+
+ richacl_for_each_entry(ace, acl) {
+ if (ace->e_flags & ~RICHACE_SPECIAL_WHO)
+ return -1;
+
+ if (richace_is_owner(ace) || richace_is_everyone(ace)) {
+ x = ace->e_mask & ~owner.defined;
+ if (richace_is_allow(ace)) {
+ unsigned int group_denied =
+ group.defined & ~group.allowed;
+
+ if (x & group_denied)
+ return -1;
+ owner.allowed |= x;
+ } else /* if (richace_is_deny(ace)) */ {
+ if (x & group.allowed)
+ return -1;
+ }
+ owner.defined |= x;
+
+ if (richace_is_everyone(ace)) {
+ x = ace->e_mask;
+ if (richace_is_allow(ace)) {
+ group.allowed |=
+ x & ~group.defined;
+ everyone.allowed |=
+ x & ~everyone.defined;
+ }
+ group.defined |= x;
+ everyone.defined |= x;
+ }
+ } else if (richace_is_group(ace)) {
+ x = ace->e_mask & ~group.defined;
+ if (richace_is_allow(ace))
+ group.allowed |= x;
+ group.defined |= x;
+ } else
+ return -1;
+ }
+
+ if (group.allowed & ~owner.defined)
+ return -1;
+
+ if (acl->a_flags & RICHACL_MASKED) {
+ if (acl->a_flags & RICHACL_WRITE_THROUGH) {
+ owner.allowed = acl->a_owner_mask;
+ everyone.allowed = acl->a_other_mask;
+ } else {
+ owner.allowed &= acl->a_owner_mask;
+ everyone.allowed &= acl->a_other_mask;
+ }
+ group.allowed &= acl->a_group_mask;
+ }
+
+ mode = (mode & ~S_IRWXUGO) |
+ (richacl_mask_to_mode(owner.allowed) << 6) |
+ (richacl_mask_to_mode(group.allowed) << 3) |
+ richacl_mask_to_mode(everyone.allowed);
+
+ /* Mask flags we can ignore */
+ x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD;
+
+ if (((richacl_mode_to_mask(mode >> 6) ^ owner.allowed) & ~x) ||
+ ((richacl_mode_to_mask(mode >> 3) ^ group.allowed) & ~x) ||
+ ((richacl_mode_to_mask(mode) ^ everyone.allowed) & ~x))
+ return -1;
+
+ *mode_p = mode;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(richacl_equiv_mode);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index a2d5600..b7128bf 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -185,6 +185,7 @@ extern unsigned int richacl_mode_to_mask(umode_t);
extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
extern struct richacl *__richacl_chmod(struct richacl *, umode_t);
+extern int richacl_equiv_mode(const struct richacl *, umode_t *);
/* richacl_inode.c */
extern int richacl_permission(struct inode *, const struct richacl *, int);
--
2.4.3
Doing a chmod() sets the file mode, which includes the file permission
bits. When a file has a richacl, the permissions that the richacl
grants need to be limited to what the new file permission bits allow.
This is done by setting the file masks in the richacl to what the file
permission bits map to. The richacl access check algorithm takes the
file masks into account, which ensures that the richacl cannot grant too
many permissions.
It is possible to explicitly add permissions to the file masks which go
beyond what the file permission bits can grant (like the
RICHACE_WRITE_ACL permission). The POSIX.1 standard calls this an
alternate file access control mechanism. A subsequent chmod() would
ensure that those permissions are disabled again.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/richacl_base.c | 42 ++++++++++++++++++++++++++++++++++++++++++
fs/richacl_inode.c | 30 ++++++++++++++++++++++++++++++
include/linux/richacl.h | 2 ++
3 files changed, 74 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 5826842..e4dd779 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -340,3 +340,45 @@ restart:
acl->a_flags &= ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED);
}
EXPORT_SYMBOL_GPL(richacl_compute_max_masks);
+
+/**
+ * __richacl_chmod - update the file masks to reflect the new mode
+ * @acl: access control list
+ * @mode: new file permission bits including the file type
+ *
+ * Return a copy of @acl where the file masks have been replaced by the file
+ * masks corresponding to the file permission bits in @mode, or returns @acl
+ * itself if the file masks are already up to date. Takes over a reference
+ * to @acl.
+ */
+struct richacl *
+__richacl_chmod(struct richacl *acl, umode_t mode)
+{
+ unsigned int x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD;
+ unsigned int owner_mask, group_mask, other_mask;
+ struct richacl *clone;
+
+ owner_mask = richacl_mode_to_mask(mode >> 6) & ~x;
+ group_mask = richacl_mode_to_mask(mode >> 3) & ~x;
+ other_mask = richacl_mode_to_mask(mode) & ~x;
+
+ if (acl->a_owner_mask == owner_mask &&
+ acl->a_group_mask == group_mask &&
+ acl->a_other_mask == other_mask &&
+ (acl->a_flags & RICHACL_MASKED) &&
+ (acl->a_flags & RICHACL_WRITE_THROUGH))
+ return acl;
+
+ clone = richacl_clone(acl, GFP_KERNEL);
+ richacl_put(acl);
+ if (!clone)
+ return ERR_PTR(-ENOMEM);
+
+ clone->a_flags |= (RICHACL_WRITE_THROUGH | RICHACL_MASKED);
+ clone->a_owner_mask = owner_mask;
+ clone->a_group_mask = group_mask;
+ clone->a_other_mask = other_mask;
+
+ return clone;
+}
+EXPORT_SYMBOL_GPL(__richacl_chmod);
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index 52c1595..e329826 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -224,3 +224,33 @@ out:
return denied ? -EACCES : 0;
}
EXPORT_SYMBOL_GPL(richacl_permission);
+
+/**
+ * richacl_chmod - filesystem chmod helper
+ * @inode: inode whose file permission bits to change
+ * @mode: new file permission bits including the file type
+ *
+ * Helper for filesystems to use to perform a chmod on the richacl of an inode.
+ */
+int
+richacl_chmod(struct inode *inode, umode_t mode)
+{
+ struct richacl *acl;
+ int retval;
+
+ if (S_ISLNK(mode))
+ return -EOPNOTSUPP;
+ if (!inode->i_op->set_richacl)
+ return -EOPNOTSUPP;
+ acl = get_richacl(inode);
+ if (IS_ERR_OR_NULL(acl))
+ return PTR_ERR(acl);
+ acl = __richacl_chmod(acl, mode);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ retval = inode->i_op->set_richacl(inode, acl);
+ richacl_put(acl);
+
+ return retval;
+}
+EXPORT_SYMBOL(richacl_chmod);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 7bf912b6..a2d5600 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -184,8 +184,10 @@ extern int richacl_masks_to_mode(const struct richacl *);
extern unsigned int richacl_mode_to_mask(umode_t);
extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
+extern struct richacl *__richacl_chmod(struct richacl *, umode_t);
/* richacl_inode.c */
extern int richacl_permission(struct inode *, const struct richacl *, int);
+extern int richacl_chmod(struct inode *, umode_t);
#endif /* __RICHACL_H */
--
2.4.3
These operations are similar to the get_acl and set_acl operations for
POSIX ACLs. The distinction between access and default ACLs doesn't exist
for richacls.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
include/linux/fs.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3db7729..e04dbb4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1682,6 +1682,7 @@ struct inode_operations {
const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
int (*permission) (struct inode *, int);
struct posix_acl * (*get_acl)(struct inode *, int);
+ struct richacl * (*get_richacl)(struct inode *);
int (*readlink) (struct dentry *, char __user *,int);
@@ -1710,6 +1711,7 @@ struct inode_operations {
umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
int (*set_acl)(struct inode *, struct posix_acl *, int);
+ int (*set_richacl)(struct inode *, struct richacl *);
} ____cacheline_aligned;
ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
--
2.4.3
POSIX ACLs and richacls are both objects allocated by kmalloc() with a
reference count which are freed by kfree_rcu(). An inode can either
cache an access and a default POSIX ACL, or a richacl (richacls do not
have default acls). To allow an inode to cache either of the two kinds
of acls, introduce a new base_acl type and convert i_acl and
i_default_acl to that type. In most cases, the vfs then doesn't care which
kind of acl an inode caches (if any).
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
drivers/staging/lustre/lustre/llite/llite_lib.c | 2 +-
fs/f2fs/acl.c | 4 +--
fs/inode.c | 4 +--
fs/jffs2/acl.c | 10 ++++--
fs/posix_acl.c | 41 +++++++++++++------------
fs/richacl_base.c | 4 +--
include/linux/fs.h | 34 ++++++++++++++++++--
include/linux/posix_acl.h | 12 +++-----
include/linux/richacl.h | 9 +++---
9 files changed, 75 insertions(+), 45 deletions(-)
diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index b2fc5b3..b587944 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -1073,7 +1073,7 @@ void ll_clear_inode(struct inode *inode)
}
#ifdef CONFIG_FS_POSIX_ACL
else if (lli->lli_posix_acl) {
- LASSERT(atomic_read(&lli->lli_posix_acl->a_refcount) == 1);
+ LASSERT(base_acl_refcount(&lli->lli_posix_acl->a_base) == 1);
LASSERT(lli->lli_remote_perms == NULL);
posix_acl_release(lli->lli_posix_acl);
lli->lli_posix_acl = NULL;
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index c8f25f7..9646197 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -270,7 +270,7 @@ static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
if (clone)
- atomic_set(&clone->a_refcount, 1);
+ base_acl_init(&clone->a_base);
}
return clone;
}
@@ -282,7 +282,7 @@ static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
umode_t mode = *mode_p;
int not_equiv = 0;
- /* assert(atomic_read(acl->a_refcount) == 1); */
+ /* assert(base_acl_refcount(&acl->a_base) == 1); */
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
diff --git a/fs/inode.c b/fs/inode.c
index 69b8b52..101d806 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -239,9 +239,9 @@ void __destroy_inode(struct inode *inode)
#ifdef CONFIG_FS_POSIX_ACL
if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
- posix_acl_release(inode->i_acl);
+ base_acl_put(inode->i_acl);
if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
- posix_acl_release(inode->i_default_acl);
+ base_acl_put(inode->i_default_acl);
#endif
this_cpu_dec(nr_inodes);
}
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
index 2f7a3c0..569cb1b 100644
--- a/fs/jffs2/acl.c
+++ b/fs/jffs2/acl.c
@@ -294,13 +294,19 @@ int jffs2_init_acl_post(struct inode *inode)
int rc;
if (inode->i_default_acl) {
- rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
+ struct posix_acl *default_acl = container_of(
+ inode->i_default_acl, struct posix_acl, a_base);
+
+ rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, default_acl);
if (rc)
return rc;
}
if (inode->i_acl) {
- rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
+ struct posix_acl *acl = container_of(
+ inode->i_acl, struct posix_acl, a_base);
+
+ rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, acl);
if (rc)
return rc;
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 55f2445..743b6dc 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -21,7 +21,7 @@
#include <linux/export.h>
#include <linux/user_namespace.h>
-static struct posix_acl **acl_by_type(struct inode *inode, int type)
+static struct base_acl **acl_by_type(struct inode *inode, int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
@@ -35,63 +35,64 @@ static struct posix_acl **acl_by_type(struct inode *inode, int type)
struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
- struct posix_acl **p = acl_by_type(inode, type);
- struct posix_acl *acl = ACCESS_ONCE(*p);
+ struct base_acl **p = acl_by_type(inode, type);
+ struct base_acl *acl = ACCESS_ONCE(*p);
if (acl) {
spin_lock(&inode->i_lock);
acl = *p;
if (acl != ACL_NOT_CACHED)
- acl = posix_acl_dup(acl);
+ base_acl_get(acl);
spin_unlock(&inode->i_lock);
}
- return acl;
+ return container_of(acl, struct posix_acl, a_base);
}
EXPORT_SYMBOL(get_cached_acl);
struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
{
- return rcu_dereference(*acl_by_type(inode, type));
+ struct base_acl *acl = rcu_dereference(*acl_by_type(inode, type));
+ return container_of(acl, struct posix_acl, a_base);
}
EXPORT_SYMBOL(get_cached_acl_rcu);
void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
{
- struct posix_acl **p = acl_by_type(inode, type);
- struct posix_acl *old;
+ struct base_acl **p = acl_by_type(inode, type);
+ struct base_acl *old;
spin_lock(&inode->i_lock);
old = *p;
- rcu_assign_pointer(*p, posix_acl_dup(acl));
+ rcu_assign_pointer(*p, &posix_acl_dup(acl)->a_base);
spin_unlock(&inode->i_lock);
if (old != ACL_NOT_CACHED)
- posix_acl_release(old);
+ base_acl_put(old);
}
EXPORT_SYMBOL(set_cached_acl);
void forget_cached_acl(struct inode *inode, int type)
{
- struct posix_acl **p = acl_by_type(inode, type);
- struct posix_acl *old;
+ struct base_acl **p = acl_by_type(inode, type);
+ struct base_acl *old;
spin_lock(&inode->i_lock);
old = *p;
*p = ACL_NOT_CACHED;
spin_unlock(&inode->i_lock);
if (old != ACL_NOT_CACHED)
- posix_acl_release(old);
+ base_acl_put(old);
}
EXPORT_SYMBOL(forget_cached_acl);
void forget_all_cached_acls(struct inode *inode)
{
- struct posix_acl *old_access, *old_default;
+ struct base_acl *old_access, *old_default;
spin_lock(&inode->i_lock);
old_access = inode->i_acl;
old_default = inode->i_default_acl;
inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
spin_unlock(&inode->i_lock);
if (old_access != ACL_NOT_CACHED)
- posix_acl_release(old_access);
+ base_acl_put(old_access);
if (old_default != ACL_NOT_CACHED)
- posix_acl_release(old_default);
+ base_acl_put(old_default);
}
EXPORT_SYMBOL(forget_all_cached_acls);
@@ -128,7 +129,7 @@ EXPORT_SYMBOL(get_acl);
void
posix_acl_init(struct posix_acl *acl, int count)
{
- atomic_set(&acl->a_refcount, 1);
+ base_acl_init(&acl->a_base);
acl->a_count = count;
}
EXPORT_SYMBOL(posix_acl_init);
@@ -161,7 +162,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
if (clone)
- atomic_set(&clone->a_refcount, 1);
+ base_acl_init(&clone->a_base);
}
return clone;
}
@@ -383,7 +384,7 @@ static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
umode_t mode = *mode_p;
int not_equiv = 0;
- /* assert(atomic_read(acl->a_refcount) == 1); */
+ /* assert(base_acl_refcount(&acl->a_base) == 1); */
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
@@ -438,7 +439,7 @@ static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
struct posix_acl_entry *pa, *pe;
- /* assert(atomic_read(acl->a_refcount) == 1); */
+ /* assert(base_acl_refcount(&acl->a_base) == 1); */
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 69b806c..5826842 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -33,7 +33,7 @@ richacl_alloc(int count, gfp_t gfp)
struct richacl *acl = kzalloc(size, gfp);
if (acl) {
- atomic_set(&acl->a_refcount, 1);
+ base_acl_init(&acl->a_base);
acl->a_count = count;
}
return acl;
@@ -52,7 +52,7 @@ richacl_clone(const struct richacl *acl, gfp_t gfp)
if (dup) {
memcpy(dup, acl, size);
- atomic_set(&dup->a_refcount, 1);
+ base_acl_init(&dup->a_base);
}
return dup;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0f560b7..3db7729 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -578,6 +578,12 @@ static inline void mapping_allow_writable(struct address_space *mapping)
#define i_size_ordered_init(inode) do { } while (0)
#endif
+struct base_acl {
+ union {
+ atomic_t ba_refcount;
+ struct rcu_head ba_rcu;
+ };
+};
struct posix_acl;
#define ACL_NOT_CACHED ((void *)(-1))
@@ -597,9 +603,9 @@ struct inode {
kgid_t i_gid;
unsigned int i_flags;
-#ifdef CONFIG_FS_POSIX_ACL
- struct posix_acl *i_acl;
- struct posix_acl *i_default_acl;
+#if defined(CONFIG_FS_POSIX_ACL)
+ struct base_acl *i_acl;
+ struct base_acl *i_default_acl;
#endif
const struct inode_operations *i_op;
@@ -3097,4 +3103,26 @@ static inline bool dir_relax(struct inode *inode)
extern bool path_noexec(const struct path *path);
extern void inode_nohighmem(struct inode *inode);
+static inline void base_acl_get(struct base_acl *acl)
+{
+ if (acl)
+ atomic_inc(&acl->ba_refcount);
+}
+
+static inline void base_acl_put(struct base_acl *acl)
+{
+ if (acl && atomic_dec_and_test(&acl->ba_refcount))
+ kfree_rcu(acl, ba_rcu);
+}
+
+static inline void base_acl_init(struct base_acl *acl)
+{
+ atomic_set(&acl->ba_refcount, 1);
+}
+
+static inline int base_acl_refcount(struct base_acl *acl)
+{
+ return atomic_read(&acl->ba_refcount);
+}
+
#endif /* _LINUX_FS_H */
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 5b5a80c..cef5428 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -43,10 +43,7 @@ struct posix_acl_entry {
};
struct posix_acl {
- union {
- atomic_t a_refcount;
- struct rcu_head a_rcu;
- };
+ struct base_acl a_base; /* must be first, see posix_acl_release() */
unsigned int a_count;
struct posix_acl_entry a_entries[0];
};
@@ -61,8 +58,7 @@ struct posix_acl {
static inline struct posix_acl *
posix_acl_dup(struct posix_acl *acl)
{
- if (acl)
- atomic_inc(&acl->a_refcount);
+ base_acl_get(&acl->a_base);
return acl;
}
@@ -72,8 +68,8 @@ posix_acl_dup(struct posix_acl *acl)
static inline void
posix_acl_release(struct posix_acl *acl)
{
- if (acl && atomic_dec_and_test(&acl->a_refcount))
- kfree_rcu(acl, a_rcu);
+ BUILD_BUG_ON(offsetof(struct posix_acl, a_base) != 0);
+ base_acl_put(&acl->a_base);
}
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 1d9f5f7..7628fad 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -31,7 +31,7 @@ struct richace {
};
struct richacl {
- atomic_t a_refcount;
+ struct base_acl a_base; /* must be first, see richacl_put() */
unsigned int a_owner_mask;
unsigned int a_group_mask;
unsigned int a_other_mask;
@@ -56,8 +56,7 @@ struct richacl {
static inline struct richacl *
richacl_get(struct richacl *acl)
{
- if (acl)
- atomic_inc(&acl->a_refcount);
+ base_acl_get(&acl->a_base);
return acl;
}
@@ -67,8 +66,8 @@ richacl_get(struct richacl *acl)
static inline void
richacl_put(struct richacl *acl)
{
- if (acl && atomic_dec_and_test(&acl->a_refcount))
- kfree(acl);
+ BUILD_BUG_ON(offsetof(struct richacl, a_base) != 0);
+ base_acl_put(&acl->a_base);
}
/**
--
2.4.3
acl_by_type(inode, type) returns a pointer to either inode->i_acl or
inode->i_default_acl depending on type. This is useful in
fs/posix_acl.c, but should never have been visible outside that file.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/posix_acl.c | 3 +--
include/linux/posix_acl.h | 1 -
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 711dd51..55f2445 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -21,7 +21,7 @@
#include <linux/export.h>
#include <linux/user_namespace.h>
-struct posix_acl **acl_by_type(struct inode *inode, int type)
+static struct posix_acl **acl_by_type(struct inode *inode, int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
@@ -32,7 +32,6 @@ struct posix_acl **acl_by_type(struct inode *inode, int type)
BUG();
}
}
-EXPORT_SYMBOL(acl_by_type);
struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 3e96a6a..5b5a80c 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -99,7 +99,6 @@ extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
extern int simple_set_acl(struct inode *, struct posix_acl *, int);
extern int simple_acl_create(struct inode *, struct inode *);
-struct posix_acl **acl_by_type(struct inode *inode, int type);
struct posix_acl *get_cached_acl(struct inode *inode, int type);
struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
--
2.4.3
A richacl roughly grants a requested access if the NFSv4 acl in the
richacl grants the requested permissions according to the NFSv4
permission check algorithm and the file mask that applies to the process
includes the requested permissions.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: "J. Bruce Fields" <[email protected]>
---
fs/Makefile | 2 +-
fs/richacl_inode.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 3 +
3 files changed, 153 insertions(+), 1 deletion(-)
create mode 100644 fs/richacl_inode.c
diff --git a/fs/Makefile b/fs/Makefile
index e5994c4..d5b45ca 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -49,7 +49,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o
obj-$(CONFIG_FHANDLE) += fhandle.o
obj-$(CONFIG_FS_RICHACL) += richacl.o
-richacl-y := richacl_base.o
+richacl-y := richacl_base.o richacl_inode.o
obj-y += quota/
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
new file mode 100644
index 0000000..99b3c93
--- /dev/null
+++ b/fs/richacl_inode.c
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/richacl.h>
+
+/**
+ * richacl_permission - richacl permission check algorithm
+ * @inode: inode to check
+ * @acl: rich acl of the inode
+ * @want: requested access (MAY_* flags)
+ *
+ * Checks if the current process is granted @mask flags in @acl.
+ */
+int
+richacl_permission(struct inode *inode, const struct richacl *acl,
+ int want)
+{
+ const struct richace *ace;
+ unsigned int mask = richacl_want_to_mask(want);
+ unsigned int requested = mask, denied = 0;
+ int in_owning_group = in_group_p(inode->i_gid);
+ int in_owner_or_group_class = in_owning_group;
+
+ /*
+ * A process is
+ * - in the owner file class if it owns the file,
+ * - in the group file class if it is in the file's owning group or
+ * it matches any of the user or group entries, and
+ * - in the other file class otherwise.
+ * The file class is only relevant for determining which file mask to
+ * apply, which only happens for masked acls.
+ */
+ if (acl->a_flags & RICHACL_MASKED) {
+ if ((acl->a_flags & RICHACL_WRITE_THROUGH) &&
+ uid_eq(current_fsuid(), inode->i_uid)) {
+ denied = requested & ~acl->a_owner_mask;
+ goto out;
+ }
+ } else {
+ /*
+ * When the acl is not masked, there is no need to determine if
+ * the process is in the group class and we can break out
+ * earlier of the loop below.
+ */
+ in_owner_or_group_class = 1;
+ }
+
+ /*
+ * Check if the acl grants the requested access and determine which
+ * file class the process is in.
+ */
+ richacl_for_each_entry(ace, acl) {
+ unsigned int ace_mask = ace->e_mask;
+
+ if (richace_is_inherit_only(ace))
+ continue;
+ if (richace_is_owner(ace)) {
+ if (!uid_eq(current_fsuid(), inode->i_uid))
+ continue;
+ goto entry_matches_owner;
+ } else if (richace_is_group(ace)) {
+ if (!in_owning_group)
+ continue;
+ } else if (richace_is_unix_user(ace)) {
+ if (!uid_eq(current_fsuid(), ace->e_id.uid))
+ continue;
+ if (uid_eq(current_fsuid(), inode->i_uid))
+ goto entry_matches_owner;
+ } else if (richace_is_unix_group(ace)) {
+ if (!in_group_p(ace->e_id.gid))
+ continue;
+ } else
+ goto entry_matches_everyone;
+
+ /*
+ * Apply the group file mask to entries other than owner@ and
+ * everyone@ or user entries matching the owner. This ensures
+ * that we grant the same permissions as the acl computed by
+ * richacl_apply_masks().
+ *
+ * Without this restriction, the following richacl would grant
+ * rw access to processes which are both the owner and in the
+ * owning group, but not to other users in the owning group,
+ * which could not be represented without masks:
+ *
+ * owner:rw::mask
+ * group@:rw::allow
+ */
+ if ((acl->a_flags & RICHACL_MASKED) && richace_is_allow(ace))
+ ace_mask &= acl->a_group_mask;
+
+entry_matches_owner:
+ /* The process is in the owner or group file class. */
+ in_owner_or_group_class = 1;
+
+entry_matches_everyone:
+ /* Check which mask flags the ACE allows or denies. */
+ if (richace_is_deny(ace))
+ denied |= ace_mask & mask;
+ mask &= ~ace_mask;
+
+ /*
+ * Keep going until we know which file class
+ * the process is in.
+ */
+ if (!mask && in_owner_or_group_class)
+ break;
+ }
+ denied |= mask;
+
+ if (acl->a_flags & RICHACL_MASKED) {
+ /*
+ * The file class a process is in determines which file mask
+ * applies. Check if that file mask also grants the requested
+ * access.
+ */
+ if (uid_eq(current_fsuid(), inode->i_uid))
+ denied |= requested & ~acl->a_owner_mask;
+ else if (in_owner_or_group_class)
+ denied |= requested & ~acl->a_group_mask;
+ else {
+ if (acl->a_flags & RICHACL_WRITE_THROUGH)
+ denied = requested & ~acl->a_other_mask;
+ else
+ denied |= requested & ~acl->a_other_mask;
+ }
+ }
+
+out:
+ return denied ? -EACCES : 0;
+}
+EXPORT_SYMBOL_GPL(richacl_permission);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 3559b2c..1d9f5f7 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -180,4 +180,7 @@ extern unsigned int richacl_mode_to_mask(umode_t);
extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
+/* richacl_inode.c */
+extern int richacl_permission(struct inode *, const struct richacl *, int);
+
#endif /* __RICHACL_H */
--
2.4.3
Compute upper bound owner, group, and other file masks with as few
permissions as possible without denying any permissions that the NFSv4
acl in a richacl grants.
This algorithm is used when a file inherits an acl at create time and
when an acl is set via a mechanism that does not provide file masks
(such as setting an acl via nfsd). When user-space sets an acl via
setxattr, the extended attribute already includes the file masks.
Setting an acl also sets the file mode permission bits: they are
determined by the file masks; see richacl_masks_to_mode().
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/richacl_base.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 1 +
2 files changed, 158 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index a393001..69b806c 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -183,3 +183,160 @@ richacl_want_to_mask(unsigned int want)
return mask;
}
EXPORT_SYMBOL_GPL(richacl_want_to_mask);
+
+/*
+ * Note: functions like richacl_allowed_to_who(), richacl_group_class_allowed(),
+ * and richacl_compute_max_masks() iterate through the entire acl in reverse
+ * order as an optimization.
+ *
+ * In the standard algorithm, aces are considered in forward order. When a
+ * process matches an ace, the permissions in the ace are either allowed or
+ * denied depending on the ace type. Once a permission has been allowed or
+ * denied, it is no longer considered in further aces.
+ *
+ * By iterating through the acl in reverse order, we can compute the same
+ * result without having to keep track of which permissions have been allowed
+ * and denied already.
+ */
+
+/**
+ * richacl_allowed_to_who - permissions allowed to a specific who value
+ *
+ * Compute the maximum mask values allowed to a specific who value, taking
+ * everyone@ aces into account.
+ */
+static unsigned int richacl_allowed_to_who(struct richacl *acl,
+ struct richace *who)
+{
+ struct richace *ace;
+ unsigned int allowed = 0;
+
+ richacl_for_each_entry_reverse(ace, acl) {
+ if (richace_is_inherit_only(ace))
+ continue;
+ if (richace_is_same_identifier(ace, who) ||
+ richace_is_everyone(ace)) {
+ if (richace_is_allow(ace))
+ allowed |= ace->e_mask;
+ else if (richace_is_deny(ace))
+ allowed &= ~ace->e_mask;
+ }
+ }
+ return allowed;
+}
+
+/**
+ * richacl_group_class_allowed - maximum permissions of the group class
+ *
+ * Compute the maximum mask values allowed to a process in the group class
+ * (i.e., a process which is not the owner but is in the owning group or
+ * matches a user or group acl entry). This includes permissions granted or
+ * denied by everyone@ aces.
+ *
+ * See richacl_compute_max_masks().
+ */
+static unsigned int richacl_group_class_allowed(struct richacl *acl)
+{
+ struct richace *ace;
+ unsigned int everyone_allowed = 0, group_class_allowed = 0;
+ int had_group_ace = 0;
+
+ richacl_for_each_entry_reverse(ace, acl) {
+ if (richace_is_inherit_only(ace) ||
+ richace_is_owner(ace))
+ continue;
+
+ if (richace_is_everyone(ace)) {
+ if (richace_is_allow(ace))
+ everyone_allowed |= ace->e_mask;
+ else if (richace_is_deny(ace))
+ everyone_allowed &= ~ace->e_mask;
+ } else {
+ group_class_allowed |=
+ richacl_allowed_to_who(acl, ace);
+
+ if (richace_is_group(ace))
+ had_group_ace = 1;
+ }
+ }
+ /*
+ * If the acl doesn't contain any group@ aces, richacl_allowed_to_who()
+ * wasn't called for the owning group. We could make that call now, but
+ * we already know the result (everyone_allowed).
+ */
+ if (!had_group_ace)
+ group_class_allowed |= everyone_allowed;
+ return group_class_allowed;
+}
+
+/**
+ * richacl_compute_max_masks - compute upper bound masks
+ *
+ * Computes upper bound owner, group, and other masks so that none of the
+ * permissions allowed by the acl are disabled.
+ *
+ * We don't make assumptions about who the owner is so that the owner can
+ * change with no effect on the file masks or file mode permission bits; this
+ * means that we must assume that all entries can match the owner.
+ */
+void richacl_compute_max_masks(struct richacl *acl)
+{
+ unsigned int gmask = ~0;
+ struct richace *ace;
+
+ /*
+ * @gmask contains all permissions which the group class is ever
+ * allowed. We use it to avoid adding permissions to the group mask
+ * from everyone@ allow aces which the group class is always denied
+ * through other aces. For example, the following acl would otherwise
+ * result in a group mask of rw:
+ *
+ * group@:w::deny
+ * everyone@:rw::allow
+ *
+ * Avoid computing @gmask for acls which do not include any group class
+ * deny aces: in such acls, the group class is never denied any
+ * permissions from everyone@ allow aces, and the group class cannot
+ * have fewer permissions than the other class.
+ */
+
+restart:
+ acl->a_owner_mask = 0;
+ acl->a_group_mask = 0;
+ acl->a_other_mask = 0;
+
+ richacl_for_each_entry_reverse(ace, acl) {
+ if (richace_is_inherit_only(ace))
+ continue;
+
+ if (richace_is_owner(ace)) {
+ if (richace_is_allow(ace))
+ acl->a_owner_mask |= ace->e_mask;
+ else if (richace_is_deny(ace))
+ acl->a_owner_mask &= ~ace->e_mask;
+ } else if (richace_is_everyone(ace)) {
+ if (richace_is_allow(ace)) {
+ acl->a_owner_mask |= ace->e_mask;
+ acl->a_group_mask |= ace->e_mask & gmask;
+ acl->a_other_mask |= ace->e_mask;
+ } else if (richace_is_deny(ace)) {
+ acl->a_owner_mask &= ~ace->e_mask;
+ acl->a_group_mask &= ~ace->e_mask;
+ acl->a_other_mask &= ~ace->e_mask;
+ }
+ } else {
+ if (richace_is_allow(ace)) {
+ acl->a_owner_mask |= ace->e_mask & gmask;
+ acl->a_group_mask |= ace->e_mask & gmask;
+ } else if (richace_is_deny(ace) && gmask == ~0) {
+ gmask = richacl_group_class_allowed(acl);
+ if (likely(gmask != ~0))
+ /* should always be true */
+ goto restart;
+ }
+ }
+ }
+
+ acl->a_flags &= ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED);
+}
+EXPORT_SYMBOL_GPL(richacl_compute_max_masks);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 9102ef0..3559b2c 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -178,5 +178,6 @@ extern void richace_copy(struct richace *, const struct richace *);
extern int richacl_masks_to_mode(const struct richacl *);
extern unsigned int richacl_mode_to_mask(umode_t);
extern unsigned int richacl_want_to_mask(unsigned int);
+extern void richacl_compute_max_masks(struct richacl *);
#endif /* __RICHACL_H */
--
2.4.3
Richacls support permissions that allow to take ownership of a file,
change the file permissions, and set the file timestamps. Support that
by introducing new permission mask flags and by checking for those mask
flags in inode_change_ok().
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/attr.c | 79 +++++++++++++++++++++++++++++++++++++++++++++---------
include/linux/fs.h | 3 +++
2 files changed, 70 insertions(+), 12 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index 7ca7fa0..2a8c49c 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -17,6 +17,65 @@
#include <linux/ima.h>
/**
+ * inode_extended_permission - permissions beyond read/write/execute
+ *
+ * Check for permissions that only richacls can currently grant.
+ */
+static int inode_extended_permission(struct inode *inode, int mask)
+{
+ if (!IS_RICHACL(inode))
+ return -EPERM;
+ return inode_permission(inode, mask);
+}
+
+static bool inode_uid_change_ok(struct inode *inode, kuid_t ia_uid)
+{
+ if (uid_eq(current_fsuid(), inode->i_uid) &&
+ uid_eq(ia_uid, inode->i_uid))
+ return true;
+ if (uid_eq(current_fsuid(), ia_uid) &&
+ inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0)
+ return true;
+ if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
+ return true;
+ return false;
+}
+
+static bool inode_gid_change_ok(struct inode *inode, kgid_t ia_gid)
+{
+ int in_group = in_group_p(ia_gid);
+ if (uid_eq(current_fsuid(), inode->i_uid) &&
+ (in_group || gid_eq(ia_gid, inode->i_gid)))
+ return true;
+ if (in_group && inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0)
+ return true;
+ if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
+ return true;
+ return false;
+}
+
+/**
+ * inode_owner_permitted_or_capable
+ *
+ * Check for permissions implicitly granted to the owner, like MAY_CHMOD or
+ * MAY_SET_TIMES. Equivalent to inode_owner_or_capable for file systems
+ * without support for those permissions.
+ */
+static bool inode_owner_permitted_or_capable(struct inode *inode, int mask)
+{
+ struct user_namespace *ns;
+
+ if (uid_eq(current_fsuid(), inode->i_uid))
+ return true;
+ if (inode_extended_permission(inode, mask) == 0)
+ return true;
+ ns = current_user_ns();
+ if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid))
+ return true;
+ return false;
+}
+
+/**
* inode_change_ok - check if attribute changes to an inode are allowed
* @inode: inode to check
* @attr: attributes to change
@@ -47,22 +106,18 @@ int inode_change_ok(struct inode *inode, struct iattr *attr)
return 0;
/* Make sure a caller can chown. */
- if ((ia_valid & ATTR_UID) &&
- (!uid_eq(current_fsuid(), inode->i_uid) ||
- !uid_eq(attr->ia_uid, inode->i_uid)) &&
- !capable_wrt_inode_uidgid(inode, CAP_CHOWN))
- return -EPERM;
+ if (ia_valid & ATTR_UID)
+ if (!inode_uid_change_ok(inode, attr->ia_uid))
+ return -EPERM;
/* Make sure caller can chgrp. */
- if ((ia_valid & ATTR_GID) &&
- (!uid_eq(current_fsuid(), inode->i_uid) ||
- (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) &&
- !capable_wrt_inode_uidgid(inode, CAP_CHOWN))
- return -EPERM;
+ if (ia_valid & ATTR_GID)
+ if (!inode_gid_change_ok(inode, attr->ia_gid))
+ return -EPERM;
/* Make sure a caller can chmod. */
if (ia_valid & ATTR_MODE) {
- if (!inode_owner_or_capable(inode))
+ if (!inode_owner_permitted_or_capable(inode, MAY_CHMOD))
return -EPERM;
/* Also check the setgid bit! */
if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
@@ -73,7 +128,7 @@ int inode_change_ok(struct inode *inode, struct iattr *attr)
/* Check for setting the inode time. */
if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
- if (!inode_owner_or_capable(inode))
+ if (!inode_owner_permitted_or_capable(inode, MAY_SET_TIMES))
return -EPERM;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index efff04f..0f560b7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -87,6 +87,9 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
#define MAY_CREATE_DIR 0x00000200
#define MAY_DELETE_CHILD 0x00000400
#define MAY_DELETE_SELF 0x00000800
+#define MAY_TAKE_OWNERSHIP 0x00001000
+#define MAY_CHMOD 0x00002000
+#define MAY_SET_TIMES 0x00004000
/*
* flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
--
2.4.3
We need to map from POSIX permissions to NFSv4 permissions when a
chmod() is done, from NFSv4 permissions to POSIX permissions when an acl
is set (which implicitly sets the file permission bits), and from the
MAY_READ/MAY_WRITE/MAY_EXEC/MAY_APPEND flags to NFSv4 permissions when
doing an access check in a richacl.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/richacl_base.c | 118 +++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 3 ++
include/uapi/linux/richacl.h | 44 ++++++++++++++++
3 files changed, 165 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index c3ec928..a393001 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -65,3 +65,121 @@ richace_copy(struct richace *to, const struct richace *from)
{
memcpy(to, from, sizeof(struct richace));
}
+
+/*
+ * richacl_mask_to_mode - compute the file permission bits from mask
+ * @mask: %RICHACE_* permission mask
+ *
+ * Compute the file permission bits corresponding to a particular set of
+ * richacl permissions.
+ *
+ * See richacl_masks_to_mode().
+ */
+static int
+richacl_mask_to_mode(unsigned int mask)
+{
+ int mode = 0;
+
+ if (mask & RICHACE_POSIX_MODE_READ)
+ mode |= S_IROTH;
+ if (mask & RICHACE_POSIX_MODE_WRITE)
+ mode |= S_IWOTH;
+ if (mask & RICHACE_POSIX_MODE_EXEC)
+ mode |= S_IXOTH;
+
+ return mode;
+}
+
+/**
+ * richacl_masks_to_mode - compute file permission bits from file masks
+ *
+ * When setting a richacl, we set the file permission bits to indicate maximum
+ * permissions: for example, we set the Write permission when a mask contains
+ * RICHACE_APPEND_DATA even if it does not also contain RICHACE_WRITE_DATA.
+ *
+ * Permissions which are not in RICHACE_POSIX_MODE_READ,
+ * RICHACE_POSIX_MODE_WRITE, or RICHACE_POSIX_MODE_EXEC cannot be represented
+ * in the file permission bits. Such permissions can still be effective, but
+ * not for new files or after a chmod(); they must be explicitly enabled in the
+ * richacl.
+ */
+int
+richacl_masks_to_mode(const struct richacl *acl)
+{
+ return richacl_mask_to_mode(acl->a_owner_mask) << 6 |
+ richacl_mask_to_mode(acl->a_group_mask) << 3 |
+ richacl_mask_to_mode(acl->a_other_mask);
+}
+EXPORT_SYMBOL_GPL(richacl_masks_to_mode);
+
+/**
+ * richacl_mode_to_mask - compute a file mask from the lowest three mode bits
+ * @mode: mode to convert to richacl permissions
+ *
+ * When the file permission bits of a file are set with chmod(), this specifies
+ * the maximum permissions that processes will get. All permissions beyond
+ * that will be removed from the file masks, and become ineffective.
+ */
+unsigned int
+richacl_mode_to_mask(umode_t mode)
+{
+ unsigned int mask = 0;
+
+ if (mode & S_IROTH)
+ mask |= RICHACE_POSIX_MODE_READ;
+ if (mode & S_IWOTH)
+ mask |= RICHACE_POSIX_MODE_WRITE;
+ if (mode & S_IXOTH)
+ mask |= RICHACE_POSIX_MODE_EXEC;
+
+ return mask;
+}
+
+/**
+ * richacl_want_to_mask - convert the iop->permission want argument to a mask
+ * @want: @want argument of the permission inode operation
+ *
+ * When checking for append, @want is (MAY_WRITE | MAY_APPEND).
+ *
+ * Richacls use the iop->may_create and iop->may_delete hooks which are used
+ * for checking if creating and deleting files is allowed. These hooks do not
+ * use richacl_want_to_mask(), so we do not have to deal with mapping MAY_WRITE
+ * to RICHACE_ADD_FILE, RICHACE_ADD_SUBDIRECTORY, and RICHACE_DELETE_CHILD
+ * here.
+ */
+unsigned int
+richacl_want_to_mask(unsigned int want)
+{
+ unsigned int mask = 0;
+
+ if (want & MAY_READ)
+ mask |= RICHACE_READ_DATA;
+ if (want & MAY_DELETE_SELF)
+ mask |= RICHACE_DELETE;
+ if (want & MAY_TAKE_OWNERSHIP)
+ mask |= RICHACE_WRITE_OWNER;
+ if (want & MAY_CHMOD)
+ mask |= RICHACE_WRITE_ACL;
+ if (want & MAY_SET_TIMES)
+ mask |= RICHACE_WRITE_ATTRIBUTES;
+ if (want & MAY_EXEC)
+ mask |= RICHACE_EXECUTE;
+ /*
+ * differentiate MAY_WRITE from these request
+ */
+ if (want & (MAY_APPEND |
+ MAY_CREATE_FILE | MAY_CREATE_DIR |
+ MAY_DELETE_CHILD)) {
+ if (want & MAY_APPEND)
+ mask |= RICHACE_APPEND_DATA;
+ if (want & MAY_CREATE_FILE)
+ mask |= RICHACE_ADD_FILE;
+ if (want & MAY_CREATE_DIR)
+ mask |= RICHACE_ADD_SUBDIRECTORY;
+ if (want & MAY_DELETE_CHILD)
+ mask |= RICHACE_DELETE_CHILD;
+ } else if (want & MAY_WRITE)
+ mask |= RICHACE_WRITE_DATA;
+ return mask;
+}
+EXPORT_SYMBOL_GPL(richacl_want_to_mask);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index edb8480..9102ef0 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -175,5 +175,8 @@ richace_is_same_identifier(const struct richace *a, const struct richace *b)
extern struct richacl *richacl_alloc(int, gfp_t);
extern struct richacl *richacl_clone(const struct richacl *, gfp_t);
extern void richace_copy(struct richace *, const struct richace *);
+extern int richacl_masks_to_mode(const struct richacl *);
+extern unsigned int richacl_mode_to_mask(umode_t);
+extern unsigned int richacl_want_to_mask(unsigned int);
#endif /* __RICHACL_H */
diff --git a/include/uapi/linux/richacl.h b/include/uapi/linux/richacl.h
index 08856f8..1ed48ac 100644
--- a/include/uapi/linux/richacl.h
+++ b/include/uapi/linux/richacl.h
@@ -96,4 +96,48 @@
RICHACE_WRITE_OWNER | \
RICHACE_SYNCHRONIZE )
+/*
+ * The POSIX permissions are supersets of the following richacl permissions:
+ *
+ * - MAY_READ maps to READ_DATA or LIST_DIRECTORY, depending on the type
+ * of the file system object.
+ *
+ * - MAY_WRITE maps to WRITE_DATA or RICHACE_APPEND_DATA for files, and to
+ * ADD_FILE, RICHACE_ADD_SUBDIRECTORY, or RICHACE_DELETE_CHILD for directories.
+ *
+ * - MAY_EXECUTE maps to RICHACE_EXECUTE.
+ *
+ * (Some of these richacl permissions have the same bit values.)
+ */
+#define RICHACE_POSIX_MODE_READ ( \
+ RICHACE_READ_DATA | \
+ RICHACE_LIST_DIRECTORY)
+#define RICHACE_POSIX_MODE_WRITE ( \
+ RICHACE_WRITE_DATA | \
+ RICHACE_ADD_FILE | \
+ RICHACE_APPEND_DATA | \
+ RICHACE_ADD_SUBDIRECTORY | \
+ RICHACE_DELETE_CHILD)
+#define RICHACE_POSIX_MODE_EXEC RICHACE_EXECUTE
+#define RICHACE_POSIX_MODE_ALL ( \
+ RICHACE_POSIX_MODE_READ | \
+ RICHACE_POSIX_MODE_WRITE | \
+ RICHACE_POSIX_MODE_EXEC)
+
+/*
+ * These permissions are always allowed no matter what the acl says.
+ */
+#define RICHACE_POSIX_ALWAYS_ALLOWED ( \
+ RICHACE_SYNCHRONIZE | \
+ RICHACE_READ_ATTRIBUTES | \
+ RICHACE_READ_ACL)
+
+/*
+ * The owner is implicitly granted these permissions under POSIX.
+ */
+#define RICHACE_POSIX_OWNER_ALLOWED ( \
+ RICHACE_WRITE_ATTRIBUTES | \
+ RICHACE_WRITE_OWNER | \
+ RICHACE_WRITE_ACL)
+
#endif /* __UAPI_RICHACL_H */
--
2.4.3
We will need to call iop->permission and iop->get_acl from
inode_change_ok() for additional permission checks, and both take a
non-const inode.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
fs/attr.c | 2 +-
include/linux/fs.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index 25b24d0..7ca7fa0 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -28,7 +28,7 @@
* Should be called as the first thing in ->setattr implementations,
* possibly after taking additional locks.
*/
-int inode_change_ok(const struct inode *inode, struct iattr *attr)
+int inode_change_ok(struct inode *inode, struct iattr *attr)
{
unsigned int ia_valid = attr->ia_valid;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 97e34ba..efff04f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2908,7 +2908,7 @@ extern int buffer_migrate_page(struct address_space *,
#define buffer_migrate_page NULL
#endif
-extern int inode_change_ok(const struct inode *, struct iattr *);
+extern int inode_change_ok(struct inode *, struct iattr *);
extern int inode_newsize_ok(const struct inode *, loff_t offset);
extern void setattr_copy(struct inode *inode, const struct iattr *attr);
--
2.4.3
A richacl consists of an NFSv4 acl and an owner, group, and other mask.
These three masks correspond to the owner, group, and other file
permission bits, but they contain NFSv4 permissions instead of POSIX
permissions.
Each entry in the NFSv4 acl applies to the file owner (OWNER@), the
owning group (GROUP@), everyone (EVERYONE@), or to a specific uid or
gid.
As in the standard POSIX file permission model, each process is the
owner, group, or other file class. A richacl grants a requested access
only if the NFSv4 acl in the richacl grants the access (according to the
NFSv4 permission check algorithm), and the file mask that applies to the
process includes the requested permissions.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/Makefile | 2 +
fs/richacl_base.c | 67 ++++++++++++++++
include/linux/richacl.h | 179 +++++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/Kbuild | 1 +
include/uapi/linux/richacl.h | 99 ++++++++++++++++++++++++
5 files changed, 348 insertions(+)
create mode 100644 fs/richacl_base.c
create mode 100644 include/linux/richacl.h
create mode 100644 include/uapi/linux/richacl.h
diff --git a/fs/Makefile b/fs/Makefile
index 79f5225..e5994c4 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -48,6 +48,8 @@ obj-$(CONFIG_COREDUMP) += coredump.o
obj-$(CONFIG_SYSCTL) += drop_caches.o
obj-$(CONFIG_FHANDLE) += fhandle.o
+obj-$(CONFIG_FS_RICHACL) += richacl.o
+richacl-y := richacl_base.o
obj-y += quota/
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
new file mode 100644
index 0000000..c3ec928
--- /dev/null
+++ b/fs/richacl_base.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2006, 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/richacl.h>
+
+MODULE_LICENSE("GPL");
+
+/**
+ * richacl_alloc - allocate a richacl
+ * @count: number of entries
+ */
+struct richacl *
+richacl_alloc(int count, gfp_t gfp)
+{
+ size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
+ struct richacl *acl = kzalloc(size, gfp);
+
+ if (acl) {
+ atomic_set(&acl->a_refcount, 1);
+ acl->a_count = count;
+ }
+ return acl;
+}
+EXPORT_SYMBOL_GPL(richacl_alloc);
+
+/**
+ * richacl_clone - create a copy of a richacl
+ */
+struct richacl *
+richacl_clone(const struct richacl *acl, gfp_t gfp)
+{
+ int count = acl->a_count;
+ size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
+ struct richacl *dup = kmalloc(size, gfp);
+
+ if (dup) {
+ memcpy(dup, acl, size);
+ atomic_set(&dup->a_refcount, 1);
+ }
+ return dup;
+}
+
+/**
+ * richace_copy - copy an acl entry
+ */
+void
+richace_copy(struct richace *to, const struct richace *from)
+{
+ memcpy(to, from, sizeof(struct richace));
+}
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
new file mode 100644
index 0000000..edb8480
--- /dev/null
+++ b/include/linux/richacl.h
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2006, 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __RICHACL_H
+#define __RICHACL_H
+
+#include <uapi/linux/richacl.h>
+
+struct richace {
+ unsigned short e_type;
+ unsigned short e_flags;
+ unsigned int e_mask;
+ union {
+ kuid_t uid;
+ kgid_t gid;
+ unsigned int special;
+ } e_id;
+};
+
+struct richacl {
+ atomic_t a_refcount;
+ unsigned int a_owner_mask;
+ unsigned int a_group_mask;
+ unsigned int a_other_mask;
+ unsigned short a_count;
+ unsigned short a_flags;
+ struct richace a_entries[0];
+};
+
+#define richacl_for_each_entry(_ace, _acl) \
+ for (_ace = (_acl)->a_entries; \
+ _ace != (_acl)->a_entries + (_acl)->a_count; \
+ _ace++)
+
+#define richacl_for_each_entry_reverse(_ace, _acl) \
+ for (_ace = (_acl)->a_entries + (_acl)->a_count - 1; \
+ _ace != (_acl)->a_entries - 1; \
+ _ace--)
+
+/**
+ * richacl_get - grab another reference to a richacl handle
+ */
+static inline struct richacl *
+richacl_get(struct richacl *acl)
+{
+ if (acl)
+ atomic_inc(&acl->a_refcount);
+ return acl;
+}
+
+/**
+ * richacl_put - free a richacl handle
+ */
+static inline void
+richacl_put(struct richacl *acl)
+{
+ if (acl && atomic_dec_and_test(&acl->a_refcount))
+ kfree(acl);
+}
+
+/**
+ * richace_is_owner - check if @ace is an OWNER@ entry
+ */
+static inline bool
+richace_is_owner(const struct richace *ace)
+{
+ return (ace->e_flags & RICHACE_SPECIAL_WHO) &&
+ ace->e_id.special == RICHACE_OWNER_SPECIAL_ID;
+}
+
+/**
+ * richace_is_group - check if @ace is a GROUP@ entry
+ */
+static inline bool
+richace_is_group(const struct richace *ace)
+{
+ return (ace->e_flags & RICHACE_SPECIAL_WHO) &&
+ ace->e_id.special == RICHACE_GROUP_SPECIAL_ID;
+}
+
+/**
+ * richace_is_everyone - check if @ace is an EVERYONE@ entry
+ */
+static inline bool
+richace_is_everyone(const struct richace *ace)
+{
+ return (ace->e_flags & RICHACE_SPECIAL_WHO) &&
+ ace->e_id.special == RICHACE_EVERYONE_SPECIAL_ID;
+}
+
+/**
+ * richace_is_unix_user - check if @ace applies to a specific user
+ */
+static inline bool
+richace_is_unix_user(const struct richace *ace)
+{
+ return !(ace->e_flags & RICHACE_SPECIAL_WHO) &&
+ !(ace->e_flags & RICHACE_IDENTIFIER_GROUP);
+}
+
+/**
+ * richace_is_unix_group - check if @ace applies to a specific group
+ */
+static inline bool
+richace_is_unix_group(const struct richace *ace)
+{
+ return !(ace->e_flags & RICHACE_SPECIAL_WHO) &&
+ (ace->e_flags & RICHACE_IDENTIFIER_GROUP);
+}
+
+/**
+ * richace_is_inherit_only - check if @ace is for inheritance only
+ *
+ * ACEs with the %RICHACE_INHERIT_ONLY_ACE flag set have no effect during
+ * permission checking.
+ */
+static inline bool
+richace_is_inherit_only(const struct richace *ace)
+{
+ return ace->e_flags & RICHACE_INHERIT_ONLY_ACE;
+}
+
+/**
+ * richace_is_inheritable - check if @ace is inheritable
+ */
+static inline bool
+richace_is_inheritable(const struct richace *ace)
+{
+ return ace->e_flags & (RICHACE_FILE_INHERIT_ACE |
+ RICHACE_DIRECTORY_INHERIT_ACE);
+}
+
+/**
+ * richace_is_allow - check if @ace is an %ALLOW type entry
+ */
+static inline bool
+richace_is_allow(const struct richace *ace)
+{
+ return ace->e_type == RICHACE_ACCESS_ALLOWED_ACE_TYPE;
+}
+
+/**
+ * richace_is_deny - check if @ace is a %DENY type entry
+ */
+static inline bool
+richace_is_deny(const struct richace *ace)
+{
+ return ace->e_type == RICHACE_ACCESS_DENIED_ACE_TYPE;
+}
+
+/**
+ * richace_is_same_identifier - are both identifiers the same?
+ */
+static inline bool
+richace_is_same_identifier(const struct richace *a, const struct richace *b)
+{
+ return !((a->e_flags ^ b->e_flags) &
+ (RICHACE_SPECIAL_WHO | RICHACE_IDENTIFIER_GROUP)) &&
+ !memcmp(&a->e_id, &b->e_id, sizeof(a->e_id));
+}
+
+extern struct richacl *richacl_alloc(int, gfp_t);
+extern struct richacl *richacl_clone(const struct richacl *, gfp_t);
+extern void richace_copy(struct richace *, const struct richace *);
+
+#endif /* __RICHACL_H */
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index ebd10e6..6e05dc8 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -351,6 +351,7 @@ header-y += reboot.h
header-y += reiserfs_fs.h
header-y += reiserfs_xattr.h
header-y += resource.h
+header-y += richacl.h
header-y += rfkill.h
header-y += romfs_fs.h
header-y += rose.h
diff --git a/include/uapi/linux/richacl.h b/include/uapi/linux/richacl.h
new file mode 100644
index 0000000..08856f8
--- /dev/null
+++ b/include/uapi/linux/richacl.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2006, 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <[email protected]>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#ifndef __UAPI_RICHACL_H
+#define __UAPI_RICHACL_H
+
+/* a_flags values */
+#define RICHACL_WRITE_THROUGH 0x40
+#define RICHACL_MASKED 0x80
+
+/* e_type values */
+#define RICHACE_ACCESS_ALLOWED_ACE_TYPE 0x0000
+#define RICHACE_ACCESS_DENIED_ACE_TYPE 0x0001
+
+/* e_flags bitflags */
+#define RICHACE_FILE_INHERIT_ACE 0x0001
+#define RICHACE_DIRECTORY_INHERIT_ACE 0x0002
+#define RICHACE_NO_PROPAGATE_INHERIT_ACE 0x0004
+#define RICHACE_INHERIT_ONLY_ACE 0x0008
+#define RICHACE_IDENTIFIER_GROUP 0x0040
+#define RICHACE_SPECIAL_WHO 0x4000
+
+/* e_mask bitflags */
+#define RICHACE_READ_DATA 0x00000001
+#define RICHACE_LIST_DIRECTORY 0x00000001
+#define RICHACE_WRITE_DATA 0x00000002
+#define RICHACE_ADD_FILE 0x00000002
+#define RICHACE_APPEND_DATA 0x00000004
+#define RICHACE_ADD_SUBDIRECTORY 0x00000004
+#define RICHACE_READ_NAMED_ATTRS 0x00000008
+#define RICHACE_WRITE_NAMED_ATTRS 0x00000010
+#define RICHACE_EXECUTE 0x00000020
+#define RICHACE_DELETE_CHILD 0x00000040
+#define RICHACE_READ_ATTRIBUTES 0x00000080
+#define RICHACE_WRITE_ATTRIBUTES 0x00000100
+#define RICHACE_WRITE_RETENTION 0x00000200
+#define RICHACE_WRITE_RETENTION_HOLD 0x00000400
+#define RICHACE_DELETE 0x00010000
+#define RICHACE_READ_ACL 0x00020000
+#define RICHACE_WRITE_ACL 0x00040000
+#define RICHACE_WRITE_OWNER 0x00080000
+#define RICHACE_SYNCHRONIZE 0x00100000
+
+/* e_id values */
+#define RICHACE_OWNER_SPECIAL_ID 0
+#define RICHACE_GROUP_SPECIAL_ID 1
+#define RICHACE_EVERYONE_SPECIAL_ID 2
+
+#define RICHACL_VALID_FLAGS ( \
+ RICHACL_WRITE_THROUGH | \
+ RICHACL_MASKED )
+
+#define RICHACE_VALID_FLAGS ( \
+ RICHACE_FILE_INHERIT_ACE | \
+ RICHACE_DIRECTORY_INHERIT_ACE | \
+ RICHACE_NO_PROPAGATE_INHERIT_ACE | \
+ RICHACE_INHERIT_ONLY_ACE | \
+ RICHACE_IDENTIFIER_GROUP | \
+ RICHACE_SPECIAL_WHO )
+
+#define RICHACE_INHERITANCE_FLAGS ( \
+ RICHACE_FILE_INHERIT_ACE | \
+ RICHACE_DIRECTORY_INHERIT_ACE | \
+ RICHACE_NO_PROPAGATE_INHERIT_ACE | \
+ RICHACE_INHERIT_ONLY_ACE )
+
+/* Valid RICHACE_* flags for directories and non-directories */
+#define RICHACE_VALID_MASK ( \
+ RICHACE_READ_DATA | RICHACE_LIST_DIRECTORY | \
+ RICHACE_WRITE_DATA | RICHACE_ADD_FILE | \
+ RICHACE_APPEND_DATA | RICHACE_ADD_SUBDIRECTORY | \
+ RICHACE_READ_NAMED_ATTRS | \
+ RICHACE_WRITE_NAMED_ATTRS | \
+ RICHACE_EXECUTE | \
+ RICHACE_DELETE_CHILD | \
+ RICHACE_READ_ATTRIBUTES | \
+ RICHACE_WRITE_ATTRIBUTES | \
+ RICHACE_WRITE_RETENTION | \
+ RICHACE_WRITE_RETENTION_HOLD | \
+ RICHACE_DELETE | \
+ RICHACE_READ_ACL | \
+ RICHACE_WRITE_ACL | \
+ RICHACE_WRITE_OWNER | \
+ RICHACE_SYNCHRONIZE )
+
+#endif /* __UAPI_RICHACL_H */
--
2.4.3
Normally, deleting a file requires MAY_WRITE access to the parent
directory. With richacls, a file may be deleted with MAY_DELETE_CHILD access
to the parent directory or with MAY_DELETE_SELF access to the file.
To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission()
when checking for delete access inside a directory, and MAY_DELETE_SELF
when checking for delete access to a file itelf.
The MAY_DELETE_SELF permission overrides the sticky directory check.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
---
fs/namei.c | 20 ++++++++++++--------
include/linux/fs.h | 2 ++
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index ae30626..59b1da0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,9 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
* this, letting us set arbitrary permissions for filesystem access without
* changing the "normal" UIDs which are used for other things.
*
- * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
- * MAY_CREATE_DIR are set. That way, file systems that don't support these
- * permissions will check for MAY_WRITE instead.
+ * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE,
+ * MAY_CREATE_DIR, or MAY_DELETE_CHILD are set. That way, file systems that
+ * don't support these permissions will check for MAY_WRITE instead.
*/
int inode_permission(struct inode *inode, int mask)
{
@@ -2626,14 +2626,18 @@ static int may_delete_or_replace(struct inode *dir, struct dentry *victim,
BUG_ON(victim->d_parent->d_inode != dir);
audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
- error = inode_permission(dir, mask);
+ error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
+ if (!error && check_sticky(dir, inode))
+ error = -EPERM;
+ if (error && IS_RICHACL(inode) &&
+ inode_permission(inode, MAY_DELETE_SELF) == 0 &&
+ inode_permission(dir, mask) == 0)
+ error = 0;
if (error)
return error;
if (IS_APPEND(dir))
return -EPERM;
-
- if (check_sticky(dir, inode) || IS_APPEND(inode) ||
- IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
+ if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
return -EPERM;
if (isdir) {
if (!d_is_dir(victim))
@@ -2651,7 +2655,7 @@ static int may_delete_or_replace(struct inode *dir, struct dentry *victim,
static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
{
- return may_delete_or_replace(dir, victim, isdir, MAY_WRITE | MAY_EXEC);
+ return may_delete_or_replace(dir, victim, isdir, MAY_EXEC);
}
static int may_replace(struct inode *dir, struct dentry *victim, bool isdir)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 02e99d7..97e34ba 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -85,6 +85,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
#define MAY_NOT_BLOCK 0x00000080
#define MAY_CREATE_FILE 0x00000100
#define MAY_CREATE_DIR 0x00000200
+#define MAY_DELETE_CHILD 0x00000400
+#define MAY_DELETE_SELF 0x00000800
/*
* flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
--
2.4.3
Richacls distinguish between creating non-directories and directories. To
support that, add an isdir parameter to may_create(). When checking
inode_permission() for create permission, pass in an additional
MAY_CREATE_FILE or MAY_CREATE_DIR mask flag.
Add may_replace() to allow checking for delete and create access when
replacing an existing file in vfs_rename().
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
fs/namei.c | 49 +++++++++++++++++++++++++++++++++----------------
include/linux/fs.h | 2 ++
2 files changed, 35 insertions(+), 16 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 5756c1a..ae30626 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,7 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
* this, letting us set arbitrary permissions for filesystem access without
* changing the "normal" UIDs which are used for other things.
*
- * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
+ * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
+ * MAY_CREATE_DIR are set. That way, file systems that don't support these
+ * permissions will check for MAY_WRITE instead.
*/
int inode_permission(struct inode *inode, int mask)
{
@@ -2611,7 +2613,8 @@ EXPORT_SYMBOL(__check_sticky);
* 10. We don't allow removal of NFS sillyrenamed files; it's handled by
* nfs_async_unlink().
*/
-static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
+static int may_delete_or_replace(struct inode *dir, struct dentry *victim,
+ bool isdir, int mask)
{
struct inode *inode = d_backing_inode(victim);
int error;
@@ -2623,7 +2626,7 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
BUG_ON(victim->d_parent->d_inode != dir);
audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
- error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
+ error = inode_permission(dir, mask);
if (error)
return error;
if (IS_APPEND(dir))
@@ -2646,6 +2649,18 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
return 0;
}
+static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
+{
+ return may_delete_or_replace(dir, victim, isdir, MAY_WRITE | MAY_EXEC);
+}
+
+static int may_replace(struct inode *dir, struct dentry *victim, bool isdir)
+{
+ int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
+ return may_delete_or_replace(dir, victim, isdir, mask | MAY_WRITE | MAY_EXEC);
+}
+
/* Check whether we can create an object with dentry child in directory
* dir.
* 1. We can't do it if child already exists (open has special treatment for
@@ -2654,14 +2669,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
* 3. We should have write and exec permissions on dir
* 4. We can't do it if dir is immutable (done in permission())
*/
-static inline int may_create(struct inode *dir, struct dentry *child)
+static inline int may_create(struct inode *dir, struct dentry *child, bool isdir)
{
+ int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
if (child->d_inode)
return -EEXIST;
if (IS_DEADDIR(dir))
return -ENOENT;
- return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+ return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
}
/*
@@ -2711,7 +2728,7 @@ EXPORT_SYMBOL(unlock_rename);
int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool want_excl)
{
- int error = may_create(dir, dentry);
+ int error = may_create(dir, dentry, false);
if (error)
return error;
@@ -3553,7 +3570,7 @@ EXPORT_SYMBOL(user_path_create);
int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
{
- int error = may_create(dir, dentry);
+ int error = may_create(dir, dentry, false);
if (error)
return error;
@@ -3645,7 +3662,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
- int error = may_create(dir, dentry);
+ int error = may_create(dir, dentry, true);
unsigned max_links = dir->i_sb->s_max_links;
if (error)
@@ -3726,7 +3743,7 @@ EXPORT_SYMBOL(dentry_unhash);
int vfs_rmdir(struct inode *dir, struct dentry *dentry)
{
- int error = may_delete(dir, dentry, 1);
+ int error = may_delete(dir, dentry, true);
if (error)
return error;
@@ -3848,7 +3865,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
{
struct inode *target = dentry->d_inode;
- int error = may_delete(dir, dentry, 0);
+ int error = may_delete(dir, dentry, false);
if (error)
return error;
@@ -3982,7 +3999,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
{
- int error = may_create(dir, dentry);
+ int error = may_create(dir, dentry, false);
if (error)
return error;
@@ -4065,7 +4082,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
if (!inode)
return -ENOENT;
- error = may_create(dir, new_dentry);
+ error = may_create(dir, new_dentry, false);
if (error)
return error;
@@ -4258,14 +4275,14 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
return error;
if (!target) {
- error = may_create(new_dir, new_dentry);
+ error = may_create(new_dir, new_dentry, is_dir);
} else {
new_is_dir = d_is_dir(new_dentry);
if (!(flags & RENAME_EXCHANGE))
- error = may_delete(new_dir, new_dentry, is_dir);
+ error = may_replace(new_dir, new_dentry, is_dir);
else
- error = may_delete(new_dir, new_dentry, new_is_dir);
+ error = may_replace(new_dir, new_dentry, new_is_dir);
}
if (error)
return error;
@@ -4528,7 +4545,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
int vfs_whiteout(struct inode *dir, struct dentry *dentry)
{
- int error = may_create(dir, dentry);
+ int error = may_create(dir, dentry, false);
if (error)
return error;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f9d2b59..02e99d7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -83,6 +83,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
#define MAY_CHDIR 0x00000040
/* called from RCU mode, don't block */
#define MAY_NOT_BLOCK 0x00000080
+#define MAY_CREATE_FILE 0x00000100
+#define MAY_CREATE_DIR 0x00000200
/*
* flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
--
2.4.3
The vfs does not apply the umask for file systems that support acls. The
test used for this used to be called IS_POSIXACL(). Switch to a new
IS_ACL() test to check for either posix acls or richacls instead. Add a new
MS_RICHACL flag and IS_RICHACL() test for richacls alone. The IS_POSIXACL()
test is still needed by nfsd.
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: J. Bruce Fields <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
fs/Kconfig | 3 +++
fs/namei.c | 8 ++++----
include/linux/fs.h | 12 ++++++++++++
include/uapi/linux/fs.h | 3 ++-
4 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/fs/Kconfig b/fs/Kconfig
index 9adee0d..f7b26f3 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -63,6 +63,9 @@ endif # BLOCK
config FS_POSIX_ACL
def_bool n
+config FS_RICHACL
+ def_bool n
+
config EXPORTFS
tristate
diff --git a/fs/namei.c b/fs/namei.c
index f624d13..5756c1a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2856,7 +2856,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
}
mode = op->mode;
- if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
+ if ((open_flag & O_CREAT) && !IS_ACL(dir))
mode &= ~current_umask();
excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT);
@@ -3040,7 +3040,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
/* Negative dentry, just create the file */
if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
umode_t mode = op->mode;
- if (!IS_POSIXACL(dir->d_inode))
+ if (!IS_ACL(dir->d_inode))
mode &= ~current_umask();
/*
* This write is needed to ensure that a
@@ -3612,7 +3612,7 @@ retry:
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- if (!IS_POSIXACL(path.dentry->d_inode))
+ if (!IS_ACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mknod(&path, dentry, mode, dev);
if (error)
@@ -3681,7 +3681,7 @@ retry:
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- if (!IS_POSIXACL(path.dentry->d_inode))
+ if (!IS_ACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mkdir(&path, dentry, mode);
if (!error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ae68100..f9d2b59 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1804,6 +1804,12 @@ struct super_operations {
#define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE)
#define IS_POSIXACL(inode) __IS_FLG(inode, MS_POSIXACL)
+#ifdef CONFIG_FS_RICHACL
+#define IS_RICHACL(inode) __IS_FLG(inode, MS_RICHACL)
+#else
+#define IS_RICHACL(inode) 0
+#endif
+
#define IS_DEADDIR(inode) ((inode)->i_flags & S_DEAD)
#define IS_NOCMTIME(inode) ((inode)->i_flags & S_NOCMTIME)
#define IS_SWAPFILE(inode) ((inode)->i_flags & S_SWAPFILE)
@@ -1817,6 +1823,12 @@ struct super_operations {
(inode)->i_rdev == WHITEOUT_DEV)
/*
+ * IS_ACL() tells the VFS to not apply the umask
+ * and use check_acl for acl permission checks when defined.
+ */
+#define IS_ACL(inode) __IS_FLG(inode, MS_POSIXACL | MS_RICHACL)
+
+/*
* Inode state bits. Protected by inode->i_lock
*
* Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 149bec8..540dbef 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -120,7 +120,7 @@ struct inodes_stat_t {
#define MS_VERBOSE 32768 /* War is peace. Verbosity is silence.
MS_VERBOSE is deprecated. */
#define MS_SILENT 32768
-#define MS_POSIXACL (1<<16) /* VFS does not apply the umask */
+#define MS_POSIXACL (1<<16) /* Supports POSIX ACLs */
#define MS_UNBINDABLE (1<<17) /* change to unbindable */
#define MS_PRIVATE (1<<18) /* change to private */
#define MS_SLAVE (1<<19) /* change to slave */
@@ -130,6 +130,7 @@ struct inodes_stat_t {
#define MS_I_VERSION (1<<23) /* Update inode I_version field */
#define MS_STRICTATIME (1<<24) /* Always perform atime updates */
#define MS_LAZYTIME (1<<25) /* Update the on-disk [acm]times lazily */
+#define MS_RICHACL (1<<26) /* Supports richacls */
/* These sb flags are internal to the kernel */
#define MS_NOSEC (1<<28)
--
2.4.3
On Mon, Feb 29, 2016 at 09:17:05AM +0100, Andreas Gruenbacher wrote:
> Al,
>
> could you please make sure you are happy with the current version of the
> richacl patch queue for the next merge window?
I'm still not happy.
For one I still see no reason to merge this broken ACL model at all.
It provides our actualy Linux users no benefit at all, while breaking
a lot of assumptions, especially by adding allow and deny ACE at the
same sime.
It also doesn't help with the issue that the main thing it's trying
to be compatible with (Windows) actually uses a fundamentally different
identifier to apply the ACLs to - as long as you're still limited
to users and groups and not guids we'll still have that mapping problem
anyway.
But besides that fundamental question on the purpose of it I also
don't think the code is suitable, more in the individual patches.
Looks fine,
Reviewed-by: Christoph Hellwig <[email protected]>
On Mon, Feb 29, 2016 at 09:17:16AM +0100, Andreas Gruenbacher wrote:
> POSIX ACLs and richacls are both objects allocated by kmalloc() with a
> reference count which are freed by kfree_rcu(). An inode can either
> cache an access and a default POSIX ACL, or a richacl (richacls do not
> have default acls). To allow an inode to cache either of the two kinds
> of acls, introduce a new base_acl type and convert i_acl and
> i_default_acl to that type. In most cases, the vfs then doesn't care which
> kind of acl an inode caches (if any).
This base_acl object is pointless. I've asked in the past to have
a proper container for the ACLs in common code, but a union
of a refcount and a rcu head doesn't really fit that category.
But this points out that the f2fs folks really need a couple of
slaps on their hands. Not if generic funtionality doesn't
fit your needs you are not going to blindly copy and paste it,
please talk to find a solution instead of duplicating it.
Folks, please come up with a suggestion to get rid of f2fs_acl_clone,
f2fs_acl_create_masq and f2fs_acl_create ASAP.
On Fri, Mar 11, 2016 at 06:01:34AM -0800, Christoph Hellwig wrote:
> On Mon, Feb 29, 2016 at 09:17:05AM +0100, Andreas Gruenbacher wrote:
> > Al,
> >
> > could you please make sure you are happy with the current version of the
> > richacl patch queue for the next merge window?
>
> I'm still not happy.
>
> For one I still see no reason to merge this broken ACL model at all.
> It provides our actualy Linux users no benefit at all, while breaking
> a lot of assumptions, especially by adding allow and deny ACE at the
> same sime.
Could you explain what you mean by "adding allow and deny ACE at the
same time"?
> It also doesn't help with the issue that the main thing it's trying
> to be compatible with (Windows) actually uses a fundamentally different
> identifier to apply the ACLs to - as long as you're still limited
> to users and groups and not guids we'll still have that mapping problem
> anyway.
Agreed, but, one step at a time? My impression is that the Samba people
still consider this a step forward for Linux compatibility.
--b.
>
> But besides that fundamental question on the purpose of it I also
> don't think the code is suitable, more in the individual patches.
> fs/Makefile | 2 +-
> fs/richacl_inode.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++++
What's the point of a tiny separate file here? All richacls files
together are still small, and it would be much preferably to have all
that code together.
> +#include <linux/richacl_xattr.h>
> +
> +MODULE_LICENSE("GPL");
what's the point given that the code isn't even modolar?
> +static void
> +fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
> +{
> + if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
> + return;
> + kname += XATTR_SYSTEM_PREFIX_LEN;
> + if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
> + !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
> + posix_acl_fix_xattr_from_user(kvalue, size);
> +}
>
> /*
> * Extended attribute SET operations
> @@ -329,9 +339,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
> error = -EFAULT;
> goto out;
> }
> - if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
> - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
> - posix_acl_fix_xattr_from_user(kvalue, size);
> + fix_xattr_from_user(kname, kvalue, size);
> }
>
> error = vfs_setxattr(d, kname, kvalue, size, flags);
> @@ -396,6 +404,17 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
> return error;
> }
>
> +static void
> +fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
> +{
> + if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
> + return;
> + kname += XATTR_SYSTEM_PREFIX_LEN;
> + if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
> + !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
> + posix_acl_fix_xattr_to_user(kvalue, size);
> +}
> +
> /*
> * Extended attribute GET operations
> */
> @@ -426,9 +445,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
>
> error = vfs_getxattr(d, kname, kvalue, size);
> if (error > 0) {
> - if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
> - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
> - posix_acl_fix_xattr_to_user(kvalue, size);
> + fix_xattr_to_user(kname, kvalue, size);
I don't see how this is related to the rest of the patch.
> +++ b/include/linux/richacl_xattr.h
What's the point in splitting this from the richacl.h header?
Same for the uapi versions.
> +struct richacl_xattr {
> + unsigned char a_version;
> + unsigned char a_flags;
Explicit __u8 for uapi headers, please.
On Mon, Feb 29, 2016 at 09:17:24AM +0100, Andreas Gruenbacher wrote:
> Add richacl xattr handler implementing the xattr operations based on the
> get_richacl and set_richacl inode operations.
Given all the issues with Posix ACLs and selinux attributes these really
should be proper syscalls instead of abusing the xattr interface.
On Fri, Mar 11, 2016 at 06:17:35AM -0800, Christoph Hellwig wrote:
> On Mon, Feb 29, 2016 at 09:17:24AM +0100, Andreas Gruenbacher wrote:
> > Add richacl xattr handler implementing the xattr operations based on the
> > get_richacl and set_richacl inode operations.
>
> Given all the issues with Posix ACLs and selinux attributes these really
> should be proper syscalls instead of abusing the xattr interface.
What are those problems exactly?
--b.
> +static inline int
> +ext4_acl_chmod(struct inode *inode, umode_t mode)
> +{
> + if (IS_RICHACL(inode))
> + return richacl_chmod(inode, inode->i_mode);
> + return posix_acl_chmod(inode, inode->i_mode);
> +}
Thi isn't ext4-specific and potentially duplicated in every caller.
Please provide this as a common helper.
Also while we're at it, the mode argument is ignore and the function
always uses inode->i_mode instead.
> +ext4_get_richacl(struct inode *inode)
> +{
> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
> + void *value = NULL;
> + struct richacl *acl = NULL;
> + int retval;
> +
> + retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
> + if (retval > 0) {
> + value = kmalloc(retval, GFP_NOFS);
> + if (!value)
> + return ERR_PTR(-ENOMEM);
> + retval = ext4_xattr_get(inode, name_index, "", value, retval);
> + }
> + if (retval > 0) {
> + acl = richacl_from_xattr(&init_user_ns, value, retval);
> + if (acl == ERR_PTR(-EINVAL))
> + acl = ERR_PTR(-EIO);
Shouldn't richacl_from_xattr return the error pointer that ->get_richacl
callers expect?
> +static int
> +__ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
> +{
> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
> + umode_t mode = inode->i_mode;
> + int retval, size;
> + void *value;
> +
> + if (richacl_equiv_mode(acl, &mode) == 0) {
> + inode->i_ctime = ext4_current_time(inode);
> + inode->i_mode = mode;
> + ext4_mark_inode_dirty(handle, inode);
> + return __ext4_remove_richacl(handle, inode);
> + }
Should this check for a NULL acl instead of special casing that
in ext4_set_richacl?
> +int
> +ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
> +{
> + struct richacl *acl = richacl_create(&inode->i_mode, dir);
> + int error;
> +
> + error = PTR_ERR(acl);
> + if (IS_ERR(acl))
> + return error;
if (IS_ERR(acl))
return PTR_ERR(acl);
> + if (acl) {
> + error = __ext4_set_richacl(handle, inode, acl);
> + richacl_put(acl);
> + }
Shouldn't richacl_create return NULL if the ACL is equivalent to the
mode bits instead of letting every filesystem figure that out on it's
own?
On Fri, Mar 11, 2016 at 3:01 PM, Christoph Hellwig <[email protected]> wrote:
> On Mon, Feb 29, 2016 at 09:17:05AM +0100, Andreas Gruenbacher wrote:
>> Al,
>>
>> could you please make sure you are happy with the current version of the
>> richacl patch queue for the next merge window?
>
> I'm still not happy.
>
> For one I still see no reason to merge this broken ACL model at all.
> It provides our actualy Linux users no benefit at all,
This permission model is useful in mixed environments that involve
UNIX and Windows machines. Think of NAS boxes with Linux and Windows
clients, for example. It also fits the NFSv4 ACL model very well. If
you're not a user dealing with such environments, then the model
likely won't provide any benefits to *you*, and you're better off with
a less complicated permission model. That doesn't say anything about
other users, though.
> while breaking a lot of assumptions,
The model is designed specifically to be compliant with the POSIX
permission model. What assumptions are you talking about?
> especially by adding allow and deny ACE at the same time.
I remember from past discussions that a permission model like the
POSIX ACL model that doesn't have DENY ACEs would be more to your
liking. This argument is dead from the start though: NFSv4 ACLs
without DENY ACEs cannot represent basic file permissions like 0604
where the owning group has fewer permissions than others, for example
(see the richaclex(7) man page). We would end up with a permission
model that isn't even compatible with the traditional POSIX file
permission model, one which nobody else implements or cares about.
> It also doesn't help with the issue that the main thing it's trying
> to be compatible with (Windows) actually uses a fundamentally different
> identifier to apply the ACLs to - as long as you're still limited
> to users and groups and not guids we'll still have that mapping problem
> anyway.
Samba has been dealing with mapping between SIDs and UIDs/GIDs for a
long time, and it's working acceptably well.
We could store SIDs in ACEs, but that wouldn't make the actual
problems go away: Files on Linux have an owner and an owning group
which are identitifed by UID/GID, whereas a file is owned by a SID
which can be either a user or a group in a SID world. Also, processes
on Linux have an owner and a list of groups which are identified by
UID/GID, so any SIDs stored in filesystems would never match a
process, anyway.
(NFSv4 refers to users and groups as opposed to SIDs, and so it
doesn't have this problem.)
Thanks,
Andreas
On Fri, Mar 11, 2016 at 3:07 PM, Christoph Hellwig <[email protected]> wrote:
> On Mon, Feb 29, 2016 at 09:17:16AM +0100, Andreas Gruenbacher wrote:
>> POSIX ACLs and richacls are both objects allocated by kmalloc() with a
>> reference count which are freed by kfree_rcu(). An inode can either
>> cache an access and a default POSIX ACL, or a richacl (richacls do not
>> have default acls). To allow an inode to cache either of the two kinds
>> of acls, introduce a new base_acl type and convert i_acl and
>> i_default_acl to that type. In most cases, the vfs then doesn't care which
>> kind of acl an inode caches (if any).
>
> This base_acl object is pointless. I've asked in the past to have
> a proper container for the ACLs in common code, but a union
> of a refcount and a rcu head doesn't really fit that category.
POSIX ACLs and RichACLs are different objects, with different members
and different algorithms operating on them. The only commonality is
that they are both kmalloc()ed, reference counted objects, and when an
inode is destroyed, both kinds of ACLs can be put in the same way,
avoiding an unnecessary if. What kind of common-code container beyond
that are you still dreaming about?
Thanks,
Andreas
On Fri, Mar 11, 2016 at 3:17 PM, Christoph Hellwig <[email protected]> wrote:
>> +#include <linux/richacl_xattr.h>
>> +
>> +MODULE_LICENSE("GPL");
>
> what's the point given that the code isn't even modolar?
A leftover, removed now.
>> +static void
>> +fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
>> +{
>> + if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
>> + return;
>> + kname += XATTR_SYSTEM_PREFIX_LEN;
>> + if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
>> + !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
>> + posix_acl_fix_xattr_from_user(kvalue, size);
>> +}
>>
>> /*
>> * Extended attribute SET operations
>> @@ -329,9 +339,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
>> error = -EFAULT;
>> goto out;
>> }
>> - if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
>> - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
>> - posix_acl_fix_xattr_from_user(kvalue, size);
>> + fix_xattr_from_user(kname, kvalue, size);
>> }
>>
>> error = vfs_setxattr(d, kname, kvalue, size, flags);
>> @@ -396,6 +404,17 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
>> return error;
>> }
>>
>> +static void
>> +fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
>> +{
>> + if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
>> + return;
>> + kname += XATTR_SYSTEM_PREFIX_LEN;
>> + if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
>> + !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
>> + posix_acl_fix_xattr_to_user(kvalue, size);
>> +}
>> +
>> /*
>> * Extended attribute GET operations
>> */
>> @@ -426,9 +445,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
>>
>> error = vfs_getxattr(d, kname, kvalue, size);
>> if (error > 0) {
>> - if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
>> - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
>> - posix_acl_fix_xattr_to_user(kvalue, size);
>> + fix_xattr_to_user(kname, kvalue, size);
>
> I don't see how this is related to the rest of the patch.
Indeed, this is unrelated now. I'll split it off.
>> +++ b/include/linux/richacl_xattr.h
>
> What's the point in splitting this from the richacl.h header?
>
> Same for the uapi versions.
>
>> +struct richacl_xattr {
>> + unsigned char a_version;
>> + unsigned char a_flags;
>
> Explicit __u8 for uapi headers, please.
Okay.
Thanks,
Andreas
On Fri, Mar 11, 2016 at 10:11 AM, Andreas Gruenbacher
<[email protected]> wrote:
> On Fri, Mar 11, 2016 at 3:01 PM, Christoph Hellwig <[email protected]> w
> The model is designed specifically to be compliant with the POSIX
> permission model. What assumptions are you talking about?
>
>> especially by adding allow and deny ACE at the same time.
>
> I remember from past discussions that a permission model like the
> POSIX ACL model that doesn't have DENY ACEs would be more to your
> liking. This argument is dead from the start though: NFSv4 ACLs
> without DENY ACEs cannot represent basic file permissions like 0604
> where the owning group has fewer permissions than others, for example
> (see the richaclex(7) man page). We would end up with a permission
> model that isn't even compatible with the traditional POSIX file
> permission model, one which nobody else implements or cares about.
NFSv4.1 (and later) and Samba's (and cifs.ko and NTFS-3g) ACL model are close
enough that doing a common approach that helps all three seems
very reasonable.
A loosely related question is what can be done for tools around existing
interfaces for ACLs. I recently found out NTFS-3g has this xattr:
static const char nf_ns_xattr_ntfs_acl[] = "system.ntfs_acl";
which allows you to query system.ntfs_acl xattr to get their full ACL
(I hope) from NTFS but it hard to read without tools to parse
the blobs better. I was prototyping adding this to cifs.ko for
the most current (SMB3 and later) protocol dialects at least
to allow backup and debug tools to use this to get the actual
ACL. cifs.ko ACL should match almost exactly to NTFS-3g's but
I wish I could find some tools that use this xattr so I could try
comparing this with cacls.exe output and smbcacls (samba tool)
for display detailed ACL information. Any idea of disk management tools
for dumping/viewing/editing ntfs ACLs on Linux for comparison?
>> It also doesn't help with the issue that the main thing it's trying
>> to be compatible with (Windows) actually uses a fundamentally different
>> identifier to apply the ACLs to - as long as you're still limited
>> to users and groups and not guids we'll still have that mapping problem
>> anyway.
>
> Samba has been dealing with mapping between SIDs and UIDs/GIDs for a
> long time, and it's working acceptably well.
>
> We could store SIDs in ACEs, but that wouldn't make the actual
> problems go away: Files on Linux have an owner and an owning group
> which are identitifed by UID/GID, whereas a file is owned by a SID
> which can be either a user or a group in a SID world. Also, processes
> on Linux have an owner and a list of groups which are identified by
> UID/GID, so any SIDs stored in filesystems would never match a
> process, anyway.
Samba's SID<->Username and SID<->UID mapping does work
acceptably well, if a bit "over-configurable" ie with
many choices for how it is done.
(the related RFC2307 mapping needed for mapping usernames
to uids across an enterprise, which Samba's winbind can
also do is helpful much more broadly - since, unlike a uid
which is too small, the username in an NFS ACLs
are basically a one to one mapping for Samba to SIDs (there
are may samba vfs modules for different OS that already
do this, including a one for an earlier version of Linux RichACLs)
Sounds like I need to quickly rework the SMB3 ACL helper functions
for cifs.ko
Also do you know where is the current version of the corresponding
vfs_richacl for
Samba which works with the current RichACL format?
--
Thanks,
Steve
On Fri, Mar 11, 2016 at 02:05:16PM -0600, Steve French wrote:
> Sounds like I need to quickly rework the SMB3 ACL helper functions
> for cifs.ko
>
> Also do you know where is the current version of the corresponding
> vfs_richacl for
> Samba which works with the current RichACL format?
I have a patch for a new vfs_richacl somewhere. I remember
sending it to Andreas for testing...
On Fri, 2016-03-11 at 09:07 -0500, J. Bruce Fields wrote:
> On Fri, Mar 11, 2016 at 06:01:34AM -0800, Christoph Hellwig wrote:
> >
> > On Mon, Feb 29, 2016 at 09:17:05AM +0100, Andreas Gruenbacher
> > wrote:
> > >
> > > Al,
> > >
> > > could you please make sure you are happy with the current version
> > > of the
> > > richacl patch queue for the next merge window?
> > I'm still not happy.
> >
> > For one I still see no reason to merge this broken ACL model at
> > all.
> > It provides our actualy Linux users no benefit at all, while
> > breaking
> > a lot of assumptions, especially by adding allow and deny ACE at
> > the
> > same sime.
> Could you explain what you mean by "adding allow and deny ACE at the
> same time"?
>
> >
> > It also doesn't help with the issue that the main thing it's trying
> > to be compatible with (Windows) actually uses a fundamentally
> > different
> > identifier to apply the ACLs to - as long as you're still limited
> > to users and groups and not guids we'll still have that mapping
> > problem
> > anyway.
> Agreed, but, one step at a time? My impression is that the Samba
> people
> still consider this a step forward for Linux compatibility.
It is a step forward, but being able to store SIDs in the ACL, would be
a much better one.
Simo.
> --b.
>
> >
> >
> > But besides that fundamental question on the purpose of it I also
> > don't think the code is suitable, more in the individual patches.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs"
> in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Mar 12, 2016 at 12:02 AM, Jeremy Allison <[email protected]> wrote:
> On Fri, Mar 11, 2016 at 02:05:16PM -0600, Steve French wrote:
>> Sounds like I need to quickly rework the SMB3 ACL helper functions
>> for cifs.ko
>>
>> Also do you know where is the current version of the corresponding
>> vfs_richacl for
>> Samba which works with the current RichACL format?
>
> I have a patch for a new vfs_richacl somewhere. I remember
> sending it to Andreas for testing...
Ah, the patch was for testing, not resting ... how could I get that mixed up.
I've applied your patch to the latest master branch, made it compile
again, and fixed a few obvious problems. The results I get with
smbcacls look reasonable now.
The code is here:
https://github.com/andreas-gruenbacher/samba richacl
I've used the following smb.conf:
[richacl]
comment = Richacl directory
path = /mnt/ext4
vfs objects = richacl
writeable = yes
browseable = yes
Is there a particular reason why you didn't make vfs_richacl a
dynamically loadable module?
Thanks,
Andreas
On Fri, Mar 11, 2016 at 3:27 PM, Christoph Hellwig <[email protected]> wrote:
>> +static inline int
>> +ext4_acl_chmod(struct inode *inode, umode_t mode)
>> +{
>> + if (IS_RICHACL(inode))
>> + return richacl_chmod(inode, inode->i_mode);
>> + return posix_acl_chmod(inode, inode->i_mode);
>> +}
>
> Thi isn't ext4-specific and potentially duplicated in every caller.
> Please provide this as a common helper.
>
> Also while we're at it, the mode argument is ignore and the function
> always uses inode->i_mode instead.
>
>> +ext4_get_richacl(struct inode *inode)
>> +{
>> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
>> + void *value = NULL;
>> + struct richacl *acl = NULL;
>> + int retval;
>> +
>> + retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
>> + if (retval > 0) {
>> + value = kmalloc(retval, GFP_NOFS);
>> + if (!value)
>> + return ERR_PTR(-ENOMEM);
>> + retval = ext4_xattr_get(inode, name_index, "", value, retval);
>> + }
>> + if (retval > 0) {
>> + acl = richacl_from_xattr(&init_user_ns, value, retval);
>> + if (acl == ERR_PTR(-EINVAL))
>> + acl = ERR_PTR(-EIO);
>
> Shouldn't richacl_from_xattr return the error pointer that ->get_richacl
> callers expect?
The xattr representation is the same on disk and at the xattr syscall
layer, and so richacl_from_xattr is used for converting into the
in-memory representation in both cases. The error codes are not the
same when a user supplies an invalid value via setxattr or NFS and
when an invalid xattr is read from disk though. I'll add a parameter
to richacl_from_xattr to make this more explicit.
>> +static int
>> +__ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
>> +{
>> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
>> + umode_t mode = inode->i_mode;
>> + int retval, size;
>> + void *value;
>> +
>> + if (richacl_equiv_mode(acl, &mode) == 0) {
>> + inode->i_ctime = ext4_current_time(inode);
>> + inode->i_mode = mode;
>> + ext4_mark_inode_dirty(handle, inode);
>> + return __ext4_remove_richacl(handle, inode);
>> + }
>
> Should this check for a NULL acl instead of special casing that
> in ext4_set_richacl?
I'm not sure I understand what you mean. When the
>> +int
>> +ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
>> +{
>> + struct richacl *acl = richacl_create(&inode->i_mode, dir);
>> + int error;
>> +
>> + error = PTR_ERR(acl);
>> + if (IS_ERR(acl))
>> + return error;
>
> if (IS_ERR(acl))
> return PTR_ERR(acl);
>
>> + if (acl) {
>> + error = __ext4_set_richacl(handle, inode, acl);
>> + richacl_put(acl);
>> + }
>
> Shouldn't richacl_create return NULL if the ACL is equivalent to the
> mode bits instead of letting every filesystem figure that out on it's
> own?
>
On Fri, Mar 11, 2016 at 3:27 PM, Christoph Hellwig <[email protected]> wrote:
>> +static int
>> +__ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
>> +{
>> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
>> + umode_t mode = inode->i_mode;
>> + int retval, size;
>> + void *value;
>> +
>> + if (richacl_equiv_mode(acl, &mode) == 0) {
>> + inode->i_ctime = ext4_current_time(inode);
>> + inode->i_mode = mode;
>> + ext4_mark_inode_dirty(handle, inode);
>> + return __ext4_remove_richacl(handle, inode);
>> + }
>
> Should this check for a NULL acl instead of special casing that
> in ext4_set_richacl?
I'm not sure I understand what you mean. When iop->set_richacl is
called with a richacl that is mode-equivalent, the file permission
bits need to be updated and any existing acl needs to be removed.
Doing this at the vfs level would result in two calls, iop->setattr
and iop->set_richacl, which can cause problems. To remove an existing
acl without setting the mode, set_richacl is called with a NULL
richacl.
__ext4_set_richacl() was split into __ext4_set_richacl() and
__ext4_remove_richacl() to align with the xfs code due to the
following comment from Dave Chinner:
http://oss.sgi.com/archives/xfs/2015-10/msg00354.html
Diff here:
https://git.kernel.org/cgit/linux/kernel/git/agruen/linux-richacl.git/diff/fs/ext4/richacl.c?id=richacl-2015-10-16&id2=richacl-2015-10-12
>> +int
>> +ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
>> +{
>> + struct richacl *acl = richacl_create(&inode->i_mode, dir);
>> + int error;
>> +
>> + error = PTR_ERR(acl);
>> + if (IS_ERR(acl))
>> + return error;
>
> if (IS_ERR(acl))
> return PTR_ERR(acl);
>
>> + if (acl) {
>> + error = __ext4_set_richacl(handle, inode, acl);
>> + richacl_put(acl);
>> + }
>
> Shouldn't richacl_create return NULL if the ACL is equivalent to the
> mode bits instead of letting every filesystem figure that out on it's
> own?
Hm, that's what it does?
Thanks,
Andreas
On Mon, Mar 14, 2016 at 12:02:13AM +0100, Andreas Gruenbacher wrote:
> On Sat, Mar 12, 2016 at 12:02 AM, Jeremy Allison <[email protected]> wrote:
> > On Fri, Mar 11, 2016 at 02:05:16PM -0600, Steve French wrote:
> >> Sounds like I need to quickly rework the SMB3 ACL helper functions
> >> for cifs.ko
> >>
> >> Also do you know where is the current version of the corresponding
> >> vfs_richacl for
> >> Samba which works with the current RichACL format?
> >
> > I have a patch for a new vfs_richacl somewhere. I remember
> > sending it to Andreas for testing...
>
> Ah, the patch was for testing, not resting ... how could I get that mixed up.
:-).
> I've applied your patch to the latest master branch, made it compile
> again, and fixed a few obvious problems. The results I get with
> smbcacls look reasonable now.
>
> The code is here:
> https://github.com/andreas-gruenbacher/samba richacl
>
> I've used the following smb.conf:
> [richacl]
> comment = Richacl directory
> path = /mnt/ext4
> vfs objects = richacl
> writeable = yes
> browseable = yes
Great ! Once richacls gets into the kernel I'll submit
this into the Samba master branch.
> Is there a particular reason why you didn't make vfs_richacl a
> dynamically loadable module?
Probably sheer lazyness :-).
On Fri, Mar 11, 2016 at 3:27 PM, Christoph Hellwig <[email protected]> wrote:
>> +static inline int
>> +ext4_acl_chmod(struct inode *inode, umode_t mode)
>> +{
>> + if (IS_RICHACL(inode))
>> + return richacl_chmod(inode, inode->i_mode);
>> + return posix_acl_chmod(inode, inode->i_mode);
>> +}
>
> Thi isn't ext4-specific and potentially duplicated in every caller.
> Please provide this as a common helper.
This can go in neither fs.h nor posix_acl.h nor richacl.h unless we
turn it into a macro, and I don't think we want to add a new header
file for such extreme trivia.
> Also while we're at it, the mode argument is ignore and the function
> always uses inode->i_mode instead.
Right, thanks.
Andreas
On Fri, Mar 11, 2016 at 09:07:57AM -0500, J. Bruce Fields wrote:
> Could you explain what you mean by "adding allow and deny ACE at the
> same time"?
NFSv4/rich ACLs have both ALLOW and DENY ACE, which is contrary to
the model how we've operated since the dawn of time.
On Fri, Mar 11, 2016 at 09:19:05AM -0500, J. Bruce Fields wrote:
> On Fri, Mar 11, 2016 at 06:17:35AM -0800, Christoph Hellwig wrote:
> > On Mon, Feb 29, 2016 at 09:17:24AM +0100, Andreas Gruenbacher wrote:
> > > Add richacl xattr handler implementing the xattr operations based on the
> > > get_richacl and set_richacl inode operations.
> >
> > Given all the issues with Posix ACLs and selinux attributes these really
> > should be proper syscalls instead of abusing the xattr interface.
>
> What are those problems exactly?
That people get confused between the attr used by the xattr syscall
interface and the attr used to store things on disk or the protocol.
This has happened every time we have non-native support, e.g. XFS, NFS,
CIFS, ntfs, etc. And it's only going to become worse.
On Fri, Mar 11, 2016 at 05:11:51PM +0100, Andreas Gruenbacher wrote:
> > while breaking a lot of assumptions,
>
> The model is designed specifically to be compliant with the POSIX
> permission model. What assumptions are you talking about?
People have long learned that we only have 'alloc' permissions. Any
model that mixes allow and deny ACE is a mistake.
> > especially by adding allow and deny ACE at the same time.
>
> I remember from past discussions that a permission model like the
> POSIX ACL model that doesn't have DENY ACEs would be more to your
> liking. This argument is dead from the start though: NFSv4 ACLs
> without DENY ACEs cannot represent basic file permissions like 0604
> where the owning group has fewer permissions than others, for example
> (see the richaclex(7) man page). We would end up with a permission
> model that isn't even compatible with the traditional POSIX file
> permission model, one which nobody else implements or cares about.
So let's stick to the model that we already have.
On Fri, Mar 11, 2016 at 05:24:45PM +0100, Andreas Gruenbacher wrote:
> POSIX ACLs and RichACLs are different objects, with different members
> and different algorithms operating on them. The only commonality is
> that they are both kmalloc()ed, reference counted objects, and when an
> inode is destroyed, both kinds of ACLs can be put in the same way,
> avoiding an unnecessary if. What kind of common-code container beyond
> that are you still dreaming about?
We still have a main object that is simply a list of ACEs. But if that
doesn't work out (I suspect it should) I don't think the common base
object is a good idea. It just leads to a lot of crazy container_of
calls. If the common object abstraction doesn't work out we'll need
a procedural one instead that has common acl_* calls that decide what
do to based on the file system acl flag.
On Fri, Mar 11, 2016 at 02:05:16PM -0600, Steve French wrote:
> A loosely related question is what can be done for tools around existing
> interfaces for ACLs. I recently found out NTFS-3g has this xattr:
>
> static const char nf_ns_xattr_ntfs_acl[] = "system.ntfs_acl";
>
> which allows you to query system.ntfs_acl xattr to get their full ACL
Bah. Filesystems really have no business exposing random system xattrs,
and we really need to add a filter to fs/xattr.c to not expose
arbitrary attrs ouside the user.* prefix.
On Mon, Mar 14, 2016 at 12:08:31AM +0100, Andreas Gruenbacher wrote:
> The xattr representation is the same on disk and at the xattr syscall
> layer, and so richacl_from_xattr is used for converting into the
> in-memory representation in both cases. The error codes are not the
> same when a user supplies an invalid value via setxattr or NFS and
> when an invalid xattr is read from disk though. I'll add a parameter
> to richacl_from_xattr to make this more explicit.
Better add a wrapper instead of a parameter.
>
> >> +static int
> >> +__ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
> >> +{
> >> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
> >> + umode_t mode = inode->i_mode;
> >> + int retval, size;
> >> + void *value;
> >> +
> >> + if (richacl_equiv_mode(acl, &mode) == 0) {
> >> + inode->i_ctime = ext4_current_time(inode);
> >> + inode->i_mode = mode;
> >> + ext4_mark_inode_dirty(handle, inode);
> >> + return __ext4_remove_richacl(handle, inode);
> >> + }
> >
> > Should this check for a NULL acl instead of special casing that
> > in ext4_set_richacl?
>
> I'm not sure I understand what you mean. When the
ext4_set_richacl checks for a NULL acl pointer and then calls into
__ext4_remove_richacl. I'd rather have that special casing in one
place.
On Mon, Mar 14, 2016 at 02:02:33PM +0100, Andreas Gruenbacher wrote:
> On Fri, Mar 11, 2016 at 3:27 PM, Christoph Hellwig <[email protected]> wrote:
> >> +static inline int
> >> +ext4_acl_chmod(struct inode *inode, umode_t mode)
> >> +{
> >> + if (IS_RICHACL(inode))
> >> + return richacl_chmod(inode, inode->i_mode);
> >> + return posix_acl_chmod(inode, inode->i_mode);
> >> +}
> >
> > Thi isn't ext4-specific and potentially duplicated in every caller.
> > Please provide this as a common helper.
>
> This can go in neither fs.h nor posix_acl.h nor richacl.h unless we
> turn it into a macro, and I don't think we want to add a new header
> file for such extreme trivia.
I'd expect us to grow a few more of thos helper if we get the sharing
right (either a real common base object, or wrappers for anything
dealing with the acl pointers in the inode), so a new linux/acl.h
should be fine.
On Tue, Mar 15, 2016 at 12:11:03AM -0700, Christoph Hellwig wrote:
> On Fri, Mar 11, 2016 at 05:11:51PM +0100, Andreas Gruenbacher wrote:
> > > while breaking a lot of assumptions,
> >
> > The model is designed specifically to be compliant with the POSIX
> > permission model. What assumptions are you talking about?
>
> People have long learned that we only have 'alloc' permissions. Any
> model that mixes allow and deny ACE is a mistake.
People can also learn and change though :-). One of the
biggest complaints people deploying Samba on Linux have is the
incompatible ACL models.
Whilst I have sympathy with your intense dislike of the
Windows ACL model, this comes down to the core of "who
do we serve ?" IMHO we should serve the users (although
I must confess I'd look awful in a TRON suit :-).
On Tue, Mar 15, 2016 at 08:45:14AM -0700, Jeremy Allison wrote:
> On Tue, Mar 15, 2016 at 12:11:03AM -0700, Christoph Hellwig wrote:
> > People have long learned that we only have 'alloc' permissions. Any
> > model that mixes allow and deny ACE is a mistake.
>
> People can also learn and change though :-). One of the
> biggest complaints people deploying Samba on Linux have is the
> incompatible ACL models.
Just to confirm: I see this a lot in the field. NFSv4 ACLs, while not a
perfect match for NTFS ACLs are a lot closer much more usable to people
who want to serve Windows clients.
Also in the pure linux world there is a lot that you can not express
with just rwx, sgid, sticky bits and friends. If you want the additional
functionality of the richacl bits, I would call it a big mistake to
omit negative aces, if just for the reason not to create yet another
ACLs flavor.
> Whilst I have sympathy with your intense dislike of the
> Windows ACL model, this comes down to the core of "who
> do we serve ?"
The world has enough confusion around ACL semanics, please do not add
more to it by creating your own model of the day.
Volker
On Tue, Mar 15, 2016 at 12:10:14AM -0700, Christoph Hellwig wrote:
> On Fri, Mar 11, 2016 at 09:19:05AM -0500, J. Bruce Fields wrote:
> > On Fri, Mar 11, 2016 at 06:17:35AM -0800, Christoph Hellwig wrote:
> > > On Mon, Feb 29, 2016 at 09:17:24AM +0100, Andreas Gruenbacher wrote:
> > > > Add richacl xattr handler implementing the xattr operations based on the
> > > > get_richacl and set_richacl inode operations.
> > >
> > > Given all the issues with Posix ACLs and selinux attributes these really
> > > should be proper syscalls instead of abusing the xattr interface.
> >
> > What are those problems exactly?
>
> That people get confused between the attr used by the xattr syscall
> interface and the attr used to store things on disk or the protocol.
> This has happened every time we have non-native support, e.g. XFS, NFS,
> CIFS, ntfs, etc. And it's only going to become worse.
How has that confusion caused problems in practice?
--b.
On Tue, Mar 15, 2016 at 3:17 PM, Volker Lendecke
<[email protected]> wrote:
> On Tue, Mar 15, 2016 at 08:45:14AM -0700, Jeremy Allison wrote:
>> On Tue, Mar 15, 2016 at 12:11:03AM -0700, Christoph Hellwig wrote:
>> > People have long learned that we only have 'alloc' permissions. Any
>> > model that mixes allow and deny ACE is a mistake.
>>
>> People can also learn and change though :-). One of the
>> biggest complaints people deploying Samba on Linux have is the
>> incompatible ACL models.
>
> Just to confirm: I see this a lot in the field. NFSv4 ACLs, while not a
> perfect match for NTFS ACLs are a lot closer much more usable to people
> who want to serve Windows clients.
Yes (and presumably Macs as well)
--
Thanks,
Steve
On Tue, Mar 15, 2016 at 2:14 AM, Christoph Hellwig <[email protected]> wrote:
> On Fri, Mar 11, 2016 at 02:05:16PM -0600, Steve French wrote:
>> A loosely related question is what can be done for tools around existing
>> interfaces for ACLs. I recently found out NTFS-3g has this xattr:
>>
>> static const char nf_ns_xattr_ntfs_acl[] = "system.ntfs_acl";
>>
>> which allows you to query system.ntfs_acl xattr to get their full ACL
>
> Bah. Filesystems really have no business exposing random system xattrs,
> and we really need to add a filter to fs/xattr.c to not expose
> arbitrary attrs ouside the user.* prefix.
Hopefully we don't consider them random system xattrs, it is
plausible that ntfs uses these for user space tools that I don't
have.
At least for cifs.ko a similar subset (querying ACLs, streams and
reparse info e.g.)
to the ntfs set would be very helpful. For example,
Being able to query the actual ACL over the wire, is important for backup
and for debug, the only question is whether to do it via an xattr (possibly
being able to have some synergy with existing ntfs-3g tools) or an ioctl
(since adding an NTFS specific syscall for a couple fs doesn't make sense).
For the specific example of the odd ntfs.streams.list xattr, I can see why
they have it. I would have mixed feelings about having no way to tell
streams and EAs from each other
since NTFS-3g displaying streams as xattrs and also Extended
Attributes (EAs) as xattrs
(and if they didn't have an additional xattr to list streams)
without a way to tell the difference (at least a system xattr to list
the alternate
data streams is useful). There is useful information in alternate data streams
that backup (and debugging) programs need for some workloads,
for example the origin (where internet explorer downloaded a file from)
and file classification information.
--
Thanks,
Steve
On Tue, Mar 15, 2016 at 8:12 AM, Christoph Hellwig <[email protected]> wrote:
> On Fri, Mar 11, 2016 at 05:24:45PM +0100, Andreas Gruenbacher wrote:
>> POSIX ACLs and RichACLs are different objects, with different members
>> and different algorithms operating on them. The only commonality is
>> that they are both kmalloc()ed, reference counted objects, and when an
>> inode is destroyed, both kinds of ACLs can be put in the same way,
>> avoiding an unnecessary if. What kind of common-code container beyond
>> that are you still dreaming about?
>
> We still have a main object that is simply a list of ACEs. But if that
> doesn't work out (I suspect it should) I don't think the common base
> object is a good idea. It just leads to a lot of crazy container_of
> calls.
There are two such container_of calls for POSIX ACLs in fs/jffs2/acl.c
[which could be replaced by get_acl()], two in fs/posix_acl.c for
POSIX ACLs, and two in fs/richacl.c for RichACLs. That's it.
> If the common object abstraction doesn't work out we'll need
> a procedural one instead that has common acl_* calls that decide what
> do to based on the file system acl flag.
I've already made such abstractions where it made sense; if you can
find more, I don't see why we shouldn't add them.
Thanks,
Andreas
On Tue, Mar 15, 2016 at 8:17 AM, Christoph Hellwig <[email protected]> wrote:
> On Mon, Mar 14, 2016 at 12:08:31AM +0100, Andreas Gruenbacher wrote:
>> The xattr representation is the same on disk and at the xattr syscall
>> layer, and so richacl_from_xattr is used for converting into the
>> in-memory representation in both cases. The error codes are not the
>> same when a user supplies an invalid value via setxattr or NFS and
>> when an invalid xattr is read from disk though. I'll add a parameter
>> to richacl_from_xattr to make this more explicit.
>
> Better add a wrapper instead of a parameter.
>
>>
>> >> +static int
>> >> +__ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
>> >> +{
>> >> + const int name_index = EXT4_XATTR_INDEX_RICHACL;
>> >> + umode_t mode = inode->i_mode;
>> >> + int retval, size;
>> >> + void *value;
>> >> +
>> >> + if (richacl_equiv_mode(acl, &mode) == 0) {
>> >> + inode->i_ctime = ext4_current_time(inode);
>> >> + inode->i_mode = mode;
>> >> + ext4_mark_inode_dirty(handle, inode);
>> >> + return __ext4_remove_richacl(handle, inode);
>> >> + }
>> >
>> > Should this check for a NULL acl instead of special casing that
>> > in ext4_set_richacl?
>>
>> I'm not sure I understand what you mean. When the
>
> ext4_set_richacl checks for a NULL acl pointer and then calls into
> __ext4_remove_richacl. I'd rather have that special casing in one
> place.
Those are two different cases: the first is where ext4_set_richacl is
called with a NULL acl to remove an existing ACL; the second is where
ext4_set_richacl is called with a mode-equivalent ACL to set the mode
and remove any existing ACL.
The check for mode-equivalent ACLs is in __ext4_set_richacl and not in
ext4_set_richacl because an inherited ACL (ext4_init_acl) can also be
mode-equivalent.
Andreas
On Tue, Mar 15, 2016 at 05:05:26PM -0400, J. Bruce Fields wrote:
> > That people get confused between the attr used by the xattr syscall
> > interface and the attr used to store things on disk or the protocol.
> > This has happened every time we have non-native support, e.g. XFS, NFS,
> > CIFS, ntfs, etc. And it's only going to become worse.
>
> How has that confusion caused problems in practice?
We had all kinds of bugs in this area that were only slowly uncovered.
We also had all kind of privilegue escalations with (non-ACLs) xattrs
as people never grasped the way different free-form namespaces have
different permission checking.
On 2016-03-15 at 21:17 +0100, Volker Lendecke wrote:
> On Tue, Mar 15, 2016 at 08:45:14AM -0700, Jeremy Allison wrote:
> > On Tue, Mar 15, 2016 at 12:11:03AM -0700, Christoph Hellwig wrote:
> > > People have long learned that we only have 'alloc' permissions. Any
> > > model that mixes allow and deny ACE is a mistake.
> >
> > People can also learn and change though :-). One of the
> > biggest complaints people deploying Samba on Linux have is the
> > incompatible ACL models.
>
> Just to confirm: I see this a lot in the field. NFSv4 ACLs, while not a
> perfect match for NTFS ACLs are a lot closer much more usable to people
> who want to serve Windows clients.
>
> Also in the pure linux world there is a lot that you can not express
> with just rwx, sgid, sticky bits and friends. If you want the additional
> functionality of the richacl bits, I would call it a big mistake to
> omit negative aces, if just for the reason not to create yet another
> ACLs flavor.
>
> > Whilst I have sympathy with your intense dislike of the
> > Windows ACL model, this comes down to the core of "who
> > do we serve ?"
>
> The world has enough confusion around ACL semanics, please do not add
> more to it by creating your own model of the day.
Exacty: Like it or not, Windows ACLs are a fact. And the
approximation by the NFSv4 ACLs is getting closer and closer
with each iteration... ;-) So it is not only that Windows world
looking into this.
As Volker and Jeremy have pointed out, the lack of ACL semantics
is one of things the users of Samba complain about most bitterly.
While Samba can work around it when it is acting exclusively on
the files, this is not an option when NFS or other protocols are
to access the data concurrently. In that case we need more
precision down in the file system. So because they make use of
*existing* formats and semantics, I think Andreas' richacls are
just the way to go, as alien as they may seem from the pure linux
filesystem point of view at first.
Cheers - Michael