On Wed, Feb 22, 2017 at 01:36:32PM +0000, David Howells wrote: > The following commit: > > commit aeaa4a79ff6a5ed912b7362f206cf8576fca538b > Author: Eric W. Biederman <[email protected]> > Date: Sat Jul 23 11:20:44 2016 -0500 > fs: Call d_automount with the filesystems creds > > brackets the call to ->d_automount() with override_creds() and > revert_creds(), setting the initial credentials for use whilst > automounting. > > This, however, breaks AFS as it's no longer able to access the calling > process's keyrings to read the destination on a mountpoint. This has gone > unnoticed till now because, to this point, stat'ing or validating the inode > caused the body of the mountpoint to be read into the pagecache (so that we > could determine whether what we were looking at was really a mountpoint). > > However, the page containing the mountpoint destination is merely *cached* > and not pinned. If it gets discarded and we try to read it in d_automount, > we may fail because we have no authentication tokens available. > > So, for the moment, revert the addition of override_creds() and > revert_creds() and their variable. > > Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") > Signed-off-by: David Howells <[email protected]> > cc: Seth Forshee <[email protected]> > cc: "Eric W. Biederman" <[email protected]> > cc: Al Viro <[email protected]>
Eric's already applied a patch that should fix this problem. As far as I know it's only been tested against NFS though, so you might want to test that it also fixes the issue with AFS. https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=93faccbbfa958a9668d3ab4e30f38dd205cee8d8 Thanks, Seth
