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;a=summary 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@xxxxxxxxxxxxxxx> know about it. >From 1995266727fa8143897e89b55f5d3c79aa828420 Mon Sep 17 00:00:00 2001 From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> Date: Mon, 22 Jan 2018 20:11:06 +0000 Subject: nfsd: auth: Fix gid sorting when rootsquash enabled From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx> Acked-by: J. Bruce Fields <bfields@xxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Wolfgang Walter <linux@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxxxxxxxxxx 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