Add access control lists for tmpfs.
Signed-off-by: Andreas Gruenbacher <[email protected]>
---
fs/Kconfig | 13 +++
include/linux/shmem_fs.h | 21 ++++++
mm/Makefile | 1
mm/shmem.c | 94 ++++++++++++++++++++++++++-
mm/shmem_acl.c | 163 +++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 290 insertions(+), 2 deletions(-)
Index: linux-2.6.18-rc5/fs/Kconfig
===================================================================
--- linux-2.6.18-rc5.orig/fs/Kconfig
+++ linux-2.6.18-rc5/fs/Kconfig
@@ -862,6 +862,19 @@ config TMPFS
See <file:Documentation/filesystems/tmpfs.txt> for details.
+config TMPFS_POSIX_ACL
+ bool "Tmpfs POSIX Access Control Lists"
+ depends on TMPFS
+ select GENERIC_ACL
+ help
+ POSIX Access Control Lists (ACLs) support permissions for users and
+ groups beyond the owner/group/world scheme.
+
+ To learn more about Access Control Lists, visit the POSIX ACLs for
+ Linux website <http://acl.bestbits.at/>.
+
+ If you don't know what Access Control Lists are, say N.
+
config HUGETLBFS
bool "HugeTLB file system support"
depends X86 || IA64 || PPC64 || SPARC64 || SUPERH || BROKEN
Index: linux-2.6.18-rc5/include/linux/shmem_fs.h
===================================================================
--- linux-2.6.18-rc5.orig/include/linux/shmem_fs.h
+++ linux-2.6.18-rc5/include/linux/shmem_fs.h
@@ -19,6 +19,10 @@ struct shmem_inode_info {
swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
struct list_head swaplist; /* chain of maybes on swap */
struct inode vfs_inode;
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ struct posix_acl *i_acl;
+ struct posix_acl *i_default_acl;
+#endif
};
struct shmem_sb_info {
@@ -36,4 +40,21 @@ static inline struct shmem_inode_info *S
return container_of(inode, struct shmem_inode_info, vfs_inode);
}
+#ifdef CONFIG_TMPFS_POSIX_ACL
+int shmem_permission(struct inode *, int, struct nameidata *);
+int shmem_acl_init(struct inode *, struct inode *);
+void shmem_acl_destroy_inode(struct inode *);
+
+extern struct xattr_handler shmem_xattr_acl_access_handler;
+extern struct xattr_handler shmem_xattr_acl_default_handler;
+#else
+static inline int shmem_acl_init(struct inode *inode, struct inode *dir)
+{
+ return 0;
+}
+static inline void shmem_acl_destroy_inode(struct inode *inode)
+{
+}
+#endif /* CONFIG_TMPFS_POSIX_ACL */
+
#endif
Index: linux-2.6.18-rc5/mm/Makefile
===================================================================
--- linux-2.6.18-rc5.orig/mm/Makefile
+++ linux-2.6.18-rc5/mm/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_HUGETLBFS) += hugetlb.o
obj-$(CONFIG_NUMA) += mempolicy.o
obj-$(CONFIG_SPARSEMEM) += sparse.o
obj-$(CONFIG_SHMEM) += shmem.o
+obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_acl.o
obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_SLAB) += slab.o
Index: linux-2.6.18-rc5/mm/shmem.c
===================================================================
--- linux-2.6.18-rc5.orig/mm/shmem.c
+++ linux-2.6.18-rc5/mm/shmem.c
@@ -26,6 +26,8 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/generic_acl.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/file.h>
@@ -176,6 +178,7 @@ static const struct address_space_operat
static struct file_operations shmem_file_operations;
static struct inode_operations shmem_inode_operations;
static struct inode_operations shmem_dir_inode_operations;
+static struct inode_operations shmem_special_inode_operations;
static struct vm_operations_struct shmem_vm_ops;
static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
@@ -630,13 +633,15 @@ static void shmem_truncate(struct inode
shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
}
+extern struct generic_acl_operations shmem_acl_ops;
+
static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
struct page *page = NULL;
int error;
- if (attr->ia_valid & ATTR_SIZE) {
+ if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
if (attr->ia_size < inode->i_size) {
/*
* If truncating down to a partial page, then
@@ -669,6 +674,10 @@ static int shmem_notify_change(struct de
error = inode_change_ok(inode, attr);
if (!error)
error = inode_setattr(inode, attr);
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ if (!error && (attr->ia_valid & ATTR_MODE))
+ error = generic_acl_chmod(inode, &shmem_acl_ops);
+#endif
if (page)
page_cache_release(page);
return error;
@@ -1362,6 +1371,7 @@ shmem_get_inode(struct super_block *sb,
switch (mode & S_IFMT) {
default:
+ inode->i_op = &shmem_special_inode_operations;
init_special_inode(inode, mode, dev);
break;
case S_IFREG:
@@ -1682,7 +1692,11 @@ shmem_mknod(struct inode *dir, struct de
iput(inode);
return error;
}
- error = 0;
+ }
+ error = shmem_acl_init(inode, dir);
+ if (error) {
+ iput(inode);
+ return error;
}
if (dir->i_mode & S_ISGID) {
inode->i_gid = dir->i_gid;
@@ -1897,6 +1911,46 @@ static struct inode_operations shmem_sym
.put_link = shmem_put_link,
};
+#ifdef CONFIG_TMPFS_POSIX_ACL
+static size_t shmem_xattr_security_list(struct inode *inode, char *list,
+ size_t list_len, const char *name,
+ size_t name_len)
+{
+ return security_inode_listsecurity(inode, list, list_len);
+}
+
+static int shmem_xattr_security_get(struct inode *inode, const char *name,
+ void *buffer, size_t size)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return security_inode_getsecurity(inode, name, buffer, size,
+ -EOPNOTSUPP);
+}
+
+static int shmem_xattr_security_set(struct inode *inode, const char *name,
+ const void *value, size_t size, int flags)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return security_inode_setsecurity(inode, name, value, size, flags);
+}
+
+struct xattr_handler shmem_xattr_security_handler = {
+ .prefix = XATTR_SECURITY_PREFIX,
+ .list = shmem_xattr_security_list,
+ .get = shmem_xattr_security_get,
+ .set = shmem_xattr_security_set,
+};
+
+static struct xattr_handler *shmem_xattr_handlers[] = {
+ &shmem_xattr_acl_access_handler,
+ &shmem_xattr_acl_default_handler,
+ &shmem_xattr_security_handler,
+ NULL
+};
+#endif
+
static int shmem_parse_options(char *options, int *mode, uid_t *uid,
gid_t *gid, unsigned long *blocks, unsigned long *inodes,
int *policy, nodemask_t *policy_nodes)
@@ -2094,6 +2148,10 @@ static int shmem_fill_super(struct super
sb->s_magic = TMPFS_MAGIC;
sb->s_op = &shmem_ops;
sb->s_time_gran = 1;
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ sb->s_xattr = shmem_xattr_handlers;
+ sb->s_flags |= MS_POSIXACL;
+#endif
inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
if (!inode)
@@ -2130,6 +2188,7 @@ static void shmem_destroy_inode(struct i
/* only struct inode is valid if it's an inline symlink */
mpol_free_shared_policy(&SHMEM_I(inode)->policy);
}
+ shmem_acl_destroy_inode(inode);
kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
}
@@ -2141,6 +2200,10 @@ static void init_once(void *foo, struct
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
inode_init_once(&p->vfs_inode);
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ p->i_acl = NULL;
+ p->i_default_acl = NULL;
+#endif
}
}
@@ -2185,6 +2248,14 @@ static struct inode_operations shmem_ino
.truncate = shmem_truncate,
.setattr = shmem_notify_change,
.truncate_range = shmem_truncate_range,
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+ .permission = shmem_permission,
+#endif
+
};
static struct inode_operations shmem_dir_inode_operations = {
@@ -2199,6 +2270,25 @@ static struct inode_operations shmem_dir
.mknod = shmem_mknod,
.rename = shmem_rename,
#endif
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ .setattr = shmem_notify_change,
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+ .permission = shmem_permission,
+#endif
+};
+
+static struct inode_operations shmem_special_inode_operations = {
+#ifdef CONFIG_TMPFS_POSIX_ACL
+ .setattr = shmem_notify_change,
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = generic_listxattr,
+ .removexattr = generic_removexattr,
+ .permission = shmem_permission,
+#endif
};
static struct super_operations shmem_ops = {
Index: linux-2.6.18-rc5/mm/shmem_acl.c
===================================================================
--- /dev/null
+++ linux-2.6.18-rc5/mm/shmem_acl.c
@@ -0,0 +1,163 @@
+/*
+ * mm/shmem_acl.c
+ *
+ * (C) 2005 Andreas Gruenbacher <[email protected]>
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/fs.h>
+#include <linux/shmem_fs.h>
+#include <linux/xattr.h>
+#include <linux/generic_acl.h>
+
+static struct posix_acl *
+shmem_get_acl(struct inode *inode, int type)
+{
+ struct posix_acl *acl = NULL;
+
+ spin_lock(&inode->i_lock);
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ acl = posix_acl_dup(SHMEM_I(inode)->i_acl);
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl);
+ break;
+ }
+ spin_unlock(&inode->i_lock);
+
+ return acl;
+}
+
+static void
+shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+ spin_lock(&inode->i_lock);
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ if (SHMEM_I(inode)->i_acl)
+ posix_acl_release(SHMEM_I(inode)->i_acl);
+ SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ if (SHMEM_I(inode)->i_default_acl)
+ posix_acl_release(SHMEM_I(inode)->i_default_acl);
+ SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl);
+ break;
+ }
+ spin_unlock(&inode->i_lock);
+}
+
+struct generic_acl_operations shmem_acl_ops = {
+ .getacl = shmem_get_acl,
+ .setacl = shmem_set_acl,
+};
+
+static size_t
+shmem_list_acl_access(struct inode *inode, char *list, size_t list_size,
+ const char *name, size_t name_len)
+{
+ return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_ACCESS,
+ list, list_size);
+}
+
+static size_t
+shmem_list_acl_default(struct inode *inode, char *list, size_t list_size,
+ const char *name, size_t name_len)
+{
+ return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT,
+ list, list_size);
+}
+
+static int
+shmem_get_acl_access(struct inode *inode, const char *name, void *buffer,
+ size_t size)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, buffer,
+ size);
+}
+
+static int
+shmem_get_acl_default(struct inode *inode, const char *name, void *buffer,
+ size_t size)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, buffer,
+ size);
+}
+
+static int
+shmem_set_acl_access(struct inode *inode, const char *name, const void *value,
+ size_t size, int flags)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, value,
+ size);
+}
+
+static int
+shmem_set_acl_default(struct inode *inode, const char *name, const void *value,
+ size_t size, int flags)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, value,
+ size);
+}
+
+struct xattr_handler shmem_xattr_acl_access_handler = {
+ .prefix = POSIX_ACL_XATTR_ACCESS,
+ .list = shmem_list_acl_access,
+ .get = shmem_get_acl_access,
+ .set = shmem_set_acl_access,
+};
+
+struct xattr_handler shmem_xattr_acl_default_handler = {
+ .prefix = POSIX_ACL_XATTR_DEFAULT,
+ .list = shmem_list_acl_default,
+ .get = shmem_get_acl_default,
+ .set = shmem_set_acl_default,
+};
+
+int
+shmem_acl_init(struct inode *inode, struct inode *dir)
+{
+ return generic_acl_init(inode, dir, &shmem_acl_ops);
+}
+
+void
+shmem_acl_destroy_inode(struct inode *inode)
+{
+ if (SHMEM_I(inode)->i_acl)
+ posix_acl_release(SHMEM_I(inode)->i_acl);
+ SHMEM_I(inode)->i_acl = NULL;
+ if (SHMEM_I(inode)->i_default_acl)
+ posix_acl_release(SHMEM_I(inode)->i_default_acl);
+ SHMEM_I(inode)->i_default_acl = NULL;
+}
+
+static int
+shmem_check_acl(struct inode *inode, int mask)
+{
+ struct posix_acl *acl = shmem_get_acl(inode, ACL_TYPE_ACCESS);
+
+ if (acl) {
+ int error = posix_acl_permission(inode, acl, mask);
+ posix_acl_release(acl);
+ return error;
+ }
+ return -EAGAIN;
+}
+
+int
+shmem_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+ return generic_permission(inode, mask, shmem_check_acl);
+}
--
Andreas Gruenbacher <[email protected]>
SUSE Labs, SUSE LINUX Products GmbH / Novell Inc.
--
VGER BF report: H 0.0585043
On Sat, 02 Sep 2006 00:14:23 +0200
Andreas Gruenbacher <[email protected]> wrote:
> +static void
> +shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
> +{
> + spin_lock(&inode->i_lock);
> + switch(type) {
> + case ACL_TYPE_ACCESS:
> + if (SHMEM_I(inode)->i_acl)
> + posix_acl_release(SHMEM_I(inode)->i_acl);
> + SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
> + break;
i_lock is "general-purpose, innermost per-inode lock". Calling kfree()
under it makes it no longer "innermost". But kfree() is surely atomic wrt
everything which filesystems and the VFS will want to do, so that's OK.
However it does point at an inefficiency. There's no need at all to be
holding onto that lock while running kfree().
--
VGER BF report: H 0
On Fri, 2006-09-01 at 14:52 -0700, Andrew Morton wrote:
> On Sat, 02 Sep 2006 00:14:23 +0200
> Andreas Gruenbacher <[email protected]> wrote:
>
> > +static void
> > +shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
> > +{
> > + spin_lock(&inode->i_lock);
> > + switch(type) {
> > + case ACL_TYPE_ACCESS:
> > + if (SHMEM_I(inode)->i_acl)
> > + posix_acl_release(SHMEM_I(inode)->i_acl);
> > + SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
> > + break;
>
> i_lock is "general-purpose, innermost per-inode lock". Calling kfree()
> under it makes it no longer "innermost". But kfree() is surely atomic wrt
> everything which filesystems and the VFS will want to do, so that's OK.
and lockdep probably will yell loudly if there's a problem.
--
VGER BF report: H 0
On Sat, 02 Sep 2006 00:14:23 +0200
Andreas Gruenbacher <[email protected]> wrote:
> --- linux-2.6.18-rc5.orig/mm/shmem.c
> +++ linux-2.6.18-rc5/mm/shmem.c
> @@ -26,6 +26,8 @@
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/fs.h>
> +#include <linux/xattr.h>
> +#include <linux/generic_acl.h>
> #include <linux/mm.h>
> #include <linux/mman.h>
> #include <linux/file.h>
> @@ -176,6 +178,7 @@ static const struct address_space_operat
> static struct file_operations shmem_file_operations;
> static struct inode_operations shmem_inode_operations;
> static struct inode_operations shmem_dir_inode_operations;
> +static struct inode_operations shmem_special_inode_operations;
> static struct vm_operations_struct shmem_vm_ops;
>
> static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
> @@ -630,13 +633,15 @@ static void shmem_truncate(struct inode
> shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
> }
>
> +extern struct generic_acl_operations shmem_acl_ops;
Can we move this declaration into a header file please?
>+static int
>+shmem_get_acl_access(struct inode *inode, const char *name, void *buffer,
>+ size_t size)
>+{
>+ if (strcmp(name, "") != 0)
>+ return -EINVAL;
An interesting thing (tested in userspace):
strcmp(somestring, "")
will only evaluate to *sometring=='\0' if I add -static to CFLAGS.
Jan Engelhardt
--
On Tuesday, 05 September 2006 21:07, Andrew Morton wrote:
> Can we move this declaration into a header file please?
That's better, yes. Attached is a version that incorporates the feedback so
far.
Thanks,
Andreas