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 4.9-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-4.9 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
@@ -59,10 +59,10 @@ 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-4.9/vsyscall-fix-permissions-for-emulate-mode-with-kaiser-pti.patch
queue-4.9/ipv6-fix-getsockopt-for-sockets-with-default-ipv6_autoflowlabel.patch
queue-4.9/nfsd-auth-fix-gid-sorting-when-rootsquash-enabled.patch