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>
This commit is contained in:
Christian Brauner 2021-01-21 14:19:22 +01:00
parent e6c9a71451
commit 02f92b3868
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
13 changed files with 24 additions and 16 deletions

View file

@ -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;
}