This is a note to let you know that I've just added the patch titled

nfsd: auth: Fix gid sorting when rootsquash enabled

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: nfsd-auth-fix-gid-sorting-when-rootsquash-enabled.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 1995266727fa8143897e89b55f5d3c79aa828420 Mon Sep 17 00:00:00 2001

From: Ben Hutchings ben.hutchings@codethink.co.uk Date: Mon, 22 Jan 2018 20:11:06 +0000 Subject: nfsd: auth: Fix gid sorting when rootsquash enabled

From: Ben Hutchings ben.hutchings@codethink.co.uk

commit 1995266727fa8143897e89b55f5d3c79aa828420 upstream.

Commit bdcf0a423ea1 ("kernel: make groups_sort calling a responsibility group_info allocators") appears to break nfsd rootsquash in a pretty major way.

It adds a call to groups_sort() inside the loop that copies/squashes gids, which means the valid gids are sorted along with the following garbage. The net result is that the highest numbered valid gids are replaced with any lower-valued garbage gids, possibly including 0.

We should sort only once, after filling in all the gids.

Fixes: bdcf0a423ea1 ("kernel: make groups_sort calling a responsibility ...") Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Acked-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Cc: Wolfgang Walter linux@stwm.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- fs/nfsd/auth.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/nfsd/auth.c +++ b/fs/nfsd/auth.c @@ -60,10 +60,10 @@ int nfsd_setuser(struct svc_rqst *rqstp, gi->gid[i] = exp->ex_anon_gid; else gi->gid[i] = rqgi->gid[i]; - - /* Each thread allocates its own gi, no race */ - groups_sort(gi); } + + /* Each thread allocates its own gi, no race */ + groups_sort(gi); } else { gi = get_group_info(rqgi); }

Patches currently in stable-queue which might be from ben.hutchings@codethink.co.uk are

queue-4.14/ipv6-fix-getsockopt-for-sockets-with-default-ipv6_autoflowlabel.patch queue-4.14/nfsd-auth-fix-gid-sorting-when-rootsquash-enabled.patch