Add two simple helpers to check permissions on a file and path
respectively and convert over some callers. It simplifies quite a few
codepaths and also reduces the churn in later patches quite a bit.
Christoph also correctly points out that this makes codepaths (e.g.
ioctls) way easier to follow that would otherwise have to do more
complex argument passing than necessary.
Link: https://lore.kernel.org/r/[email protected]
Cc: David Howells <[email protected]>
Cc: Al Viro <[email protected]>
Cc: [email protected]
Suggested-by: Christoph Hellwig <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
---
/* v2 */
patch not present
/* v3 */
patch not present
/* v4 */
patch not present
/* v5 */
patch not present
/* v6 */
base-commit: 19c329f6808995b142b3966301f217c831e7cf31
- Christoph Hellwig <[email protected]>:
- Make file_user_ns() static inline.
- Add file_permission() and path_permission() helpers.
---
fs/init.c | 6 +++---
fs/notify/fanotify/fanotify_user.c | 2 +-
fs/notify/inotify/inotify_user.c | 2 +-
fs/open.c | 6 +++---
fs/udf/file.c | 2 +-
fs/verity/enable.c | 2 +-
include/linux/fs.h | 8 ++++++++
kernel/bpf/inode.c | 2 +-
kernel/sys.c | 2 +-
mm/madvise.c | 2 +-
mm/memcontrol.c | 2 +-
mm/mincore.c | 2 +-
net/unix/af_unix.c | 2 +-
13 files changed, 24 insertions(+), 16 deletions(-)
diff --git a/fs/init.c b/fs/init.c
index e9c320a48cf1..02723bea8499 100644
--- a/fs/init.c
+++ b/fs/init.c
@@ -49,7 +49,7 @@ int __init init_chdir(const char *filename)
error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (error)
return error;
- error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
+ error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (!error)
set_fs_pwd(current->fs, &path);
path_put(&path);
@@ -64,7 +64,7 @@ int __init init_chroot(const char *filename)
error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (error)
return error;
- error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
+ error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
error = -EPERM;
@@ -118,7 +118,7 @@ int __init init_eaccess(const char *filename)
error = kern_path(filename, LOOKUP_FOLLOW, &path);
if (error)
return error;
- error = inode_permission(d_inode(path.dentry), MAY_ACCESS);
+ error = path_permission(&path, MAY_ACCESS);
path_put(&path);
return error;
}
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index dcab112e1f00..64cfc1a3015d 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -702,7 +702,7 @@ static int fanotify_find_path(int dfd, const char __user *filename,
}
/* you can only watch an inode if you have read permissions on it */
- ret = inode_permission(path->dentry->d_inode, MAY_READ);
+ ret = path_permission(path, MAY_READ);
if (ret) {
path_put(path);
goto out;
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index 59c177011a0f..e1155d32ef6f 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -352,7 +352,7 @@ static int inotify_find_inode(const char __user *dirname, struct path *path,
if (error)
return error;
/* you can only watch an inode if you have read permissions on it */
- error = inode_permission(path->dentry->d_inode, MAY_READ);
+ error = path_permission(path, MAY_READ);
if (error) {
path_put(path);
return error;
diff --git a/fs/open.c b/fs/open.c
index 1e06e443a565..cd1efd254cad 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -492,7 +492,7 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename)
if (error)
goto out;
- error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
+ error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
@@ -521,7 +521,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd)
if (!d_can_lookup(f.file->f_path.dentry))
goto out_putf;
- error = inode_permission(file_inode(f.file), MAY_EXEC | MAY_CHDIR);
+ error = file_permission(f.file, MAY_EXEC | MAY_CHDIR);
if (!error)
set_fs_pwd(current->fs, &f.file->f_path);
out_putf:
@@ -540,7 +540,7 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename)
if (error)
goto out;
- error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
+ error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
diff --git a/fs/udf/file.c b/fs/udf/file.c
index ad8eefad27d7..3671a40ed3c3 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -183,7 +183,7 @@ long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
long old_block, new_block;
int result;
- if (inode_permission(inode, MAY_READ) != 0) {
+ if (file_permission(filp, MAY_READ) != 0) {
udf_debug("no permission to access inode %lu\n", inode->i_ino);
return -EPERM;
}
diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index f7e997a01ad0..77e159a0346b 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c
@@ -369,7 +369,7 @@ int fsverity_ioctl_enable(struct file *filp, const void __user *uarg)
* has verity enabled, and to stabilize the data being hashed.
*/
- err = inode_permission(inode, MAY_WRITE);
+ err = file_permission(filp, MAY_WRITE);
if (err)
return err;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3165998e2294..bcd17097d441 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2812,6 +2812,14 @@ static inline int bmap(struct inode *inode, sector_t *block)
extern int notify_change(struct dentry *, struct iattr *, struct inode **);
extern int inode_permission(struct inode *, int);
extern int generic_permission(struct inode *, int);
+static inline int file_permission(struct file *file, int mask)
+{
+ return inode_permission(file_inode(file), mask);
+}
+static inline int path_permission(const struct path *path, int mask)
+{
+ return inode_permission(d_inode(path->dentry), mask);
+}
extern int __check_sticky(struct inode *dir, struct inode *inode);
static inline bool execute_ok(struct inode *inode)
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index dd4b7fd60ee7..8962f139521e 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -507,7 +507,7 @@ static void *bpf_obj_do_get(const char __user *pathname,
return ERR_PTR(ret);
inode = d_backing_inode(path.dentry);
- ret = inode_permission(inode, ACC_MODE(flags));
+ ret = path_permission(&path, ACC_MODE(flags));
if (ret)
goto out;
diff --git a/kernel/sys.c b/kernel/sys.c
index 51f00fe20e4d..138fb253b344 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1848,7 +1848,7 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
goto exit;
- err = inode_permission(inode, MAY_EXEC);
+ err = file_permission(exe.file, MAY_EXEC);
if (err)
goto exit;
diff --git a/mm/madvise.c b/mm/madvise.c
index 6a660858784b..175c5582d8a9 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -540,7 +540,7 @@ static inline bool can_do_pageout(struct vm_area_struct *vma)
* opens a side channel.
*/
return inode_owner_or_capable(file_inode(vma->vm_file)) ||
- inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0;
+ file_permission(vma->vm_file, MAY_WRITE) == 0;
}
static long madvise_pageout(struct vm_area_struct *vma,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 605f671203ef..cf9076f58582 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4899,7 +4899,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
/* the process need read permission on control file */
/* AV: shouldn't we check that it's been opened for read instead? */
- ret = inode_permission(file_inode(cfile.file), MAY_READ);
+ ret = file_permission(cfile.file, MAY_READ);
if (ret < 0)
goto out_put_cfile;
diff --git a/mm/mincore.c b/mm/mincore.c
index 02db1a834021..7bdb4673f776 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -167,7 +167,7 @@ static inline bool can_do_mincore(struct vm_area_struct *vma)
* mappings, which opens a side channel.
*/
return inode_owner_or_capable(file_inode(vma->vm_file)) ||
- inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0;
+ file_permission(vma->vm_file, MAY_WRITE) == 0;
}
static const struct mm_walk_ops mincore_walk_ops = {
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 41c3303c3357..18453d15dddf 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -936,7 +936,7 @@ static struct sock *unix_find_other(struct net *net,
if (err)
goto fail;
inode = d_backing_inode(path.dentry);
- err = inode_permission(inode, MAY_WRITE);
+ err = path_permission(&path, MAY_WRITE);
if (err)
goto put_fail;
--
2.30.0
On Thu, 21 Jan 2021, Christian Brauner wrote:
> Add two simple helpers to check permissions on a file and path
> respectively and convert over some callers. It simplifies quite a few
> codepaths and also reduces the churn in later patches quite a bit.
> Christoph also correctly points out that this makes codepaths (e.g.
> ioctls) way easier to follow that would otherwise have to do more
> complex argument passing than necessary.
>
> Link: https://lore.kernel.org/r/[email protected]
> Cc: David Howells <[email protected]>
> Cc: Al Viro <[email protected]>
> Cc: [email protected]
> Suggested-by: Christoph Hellwig <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>
> Signed-off-by: Christian Brauner <[email protected]>
Reviewed-by: James Morris <[email protected]>
--
James Morris
<[email protected]>