From 1995266727fa8143897e89b55f5d3c79aa828420 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 22 Jan 2018 20:11:06 +0000 Subject: [PATCH] nfsd: auth: Fix gid sorting when rootsquash enabled 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 Acked-by: J. Bruce Fields Signed-off-by: Linus Torvalds --- fs/nfsd/auth.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c index f650e475d8f0d8..fdf2aad7347090 100644 --- a/fs/nfsd/auth.c +++ b/fs/nfsd/auth.c @@ -60,10 +60,10 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp) 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); }