From 58330ec2fecd1c3a6b8759b292f32f82dfd058ba Mon Sep 17 00:00:00 2001 From: Thiago Rafael Becker Date: Thu, 14 Dec 2017 15:33:12 -0800 Subject: kernel: make groups_sort calling a responsibility group_info allocators commit bdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758 upstream. In testing, we found that nfsd threads may call set_groups in parallel for the same entry cached in auth.unix.gid, racing in the call of groups_sort, corrupting the groups for that entry and leading to permission denials for the client. This patch: - Make groups_sort globally visible. - Move the call to groups_sort to the modifiers of group_info - Remove the call to groups_sort from set_groups Link: http://lkml.kernel.org/r/20171211151420.18655-1-thiago.becker@gmail.com Signed-off-by: Thiago Rafael Becker Reviewed-by: Matthew Wilcox Reviewed-by: NeilBrown Acked-by: "J. Bruce Fields" Cc: Al Viro Cc: Martin Schwidefsky Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/auth.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/nfsd/auth.c') diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c index 9d46a0bdd9f9..a260060042ad 100644 --- a/fs/nfsd/auth.c +++ b/fs/nfsd/auth.c @@ -59,6 +59,9 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp) GROUP_AT(gi, i) = exp->ex_anon_gid; else GROUP_AT(gi, i) = GROUP_AT(rqgi, i); + + /* Each thread allocates its own gi, no race */ + groups_sort(gi); } } else { gi = get_group_info(rqgi); -- cgit v1.2.3 From 3f84339bd344b2cf0afe64b78d3964bb6422d0f3 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 22 Jan 2018 20:11:06 +0000 Subject: nfsd: auth: Fix gid sorting when rootsquash enabled 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 Acked-by: J. Bruce Fields Signed-off-by: Linus Torvalds Cc: Wolfgang Walter Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/auth.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs/nfsd/auth.c') diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c index a260060042ad..67eb154af881 100644 --- a/fs/nfsd/auth.c +++ b/fs/nfsd/auth.c @@ -60,9 +60,10 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp) else GROUP_AT(gi, i) = GROUP_AT(rqgi, 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); } -- cgit v1.2.3