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authorThiago Rafael Becker <thiago.becker@gmail.com>2017-12-14 15:33:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-12-14 16:00:49 -0800
commitbdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758 (patch)
tree942b1b8fa9b1e52503d5f9894d43674255813566 /fs
parent1f704fd0d14043e76e80f6b8b2251b9b2cedcca6 (diff)
kernel: make groups_sort calling a responsibility group_info allocators
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 <thiago.becker@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: NeilBrown <neilb@suse.com> Acked-by: "J. Bruce Fields" <bfields@fieldses.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfsd/auth.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index 697f8ae7792d..f650e475d8f0 100644
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -60,6 +60,9 @@ 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);
}
} else {
gi = get_group_info(rqgi);