fs: add file and path permissions helpers
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/20210121131959.646623-4-christian.brauner@ubuntu.com
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff --git a/kernel/sys.c b/kernel/sys.c
index 51f00fe..138fb25 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;
