fuse: fix permission checking on sticky directories

The VFS checks sticky bits on the parent directory even if the filesystem
defines it's own ->permission().  In some situations (sshfs, mountlo, etc) the
user does have permission to delete a file even if the attribute based
checking would not allow it.

So work around this by storing the permission bits separately and returning
them in stat(), but cutting the permission bits off from inode->i_mode.

This is slightly hackish, but it's probably not worth it to add new
infrastructure in VFS and a slight performance penalty for all filesystems,
just for the sake of fuse.

[Jan Engelhardt] cosmetic fixes
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 9ee2a6bbfa37..8ea4ea13ec5f 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1054,8 +1054,10 @@ static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
         if (fi->i_time < get_jiffies_64())
                 err = fuse_do_getattr(inode);
 
-        if (!err)
+        if (!err) {
                 generic_fillattr(inode, stat);
+                stat->mode = fi->orig_i_mode;
+        }
 
         return err;
 }