nfsd: auth: Fix gid sorting when rootsquash enabled

Commit bdcf0a4 ("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: bdcf0a4 ("kernel: make groups_sort calling a responsibility ...") Signed-off-by: Ben Hutchings <[email protected]> Acked-by: J. Bruce Fields <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
siemens · Jan 23, 2018 · 1995266 · 1995266
1 parent a0ec1de
commit 1995266
Showing 1 changed file with 3 additions and 3 deletions.
diff --git 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);
 	}