Prevent NULL dereference if group has no members

Fix bug #7014 (domain mode winbind crashes retriveing empty group members).
(cherry picked from commit 5fd32614f147a045aaee30ed9cf62e42ac6e30d8)

diff --git a/source/winbindd/winbindd_rpc.c b/source/winbindd/winbindd_rpc.c
index db43559436f31d84cea5e60ca4ceac00340fa2bd..459a84460dc1a7e5b0bf414e818c5e6a2fa53e1a 100644 (file)
--- a/source/winbindd/winbindd_rpc.c
+++ b/source/winbindd/winbindd_rpc.c
@@ -787,16 +787,16 @@ static NTSTATUS lookup_groupmem(struct winbindd_domain *domain,
         if (!NT_STATUS_IS_OK(result))
                return result;
 
-       *num_names = rids->count;
-       rid_mem = rids->rids;
-
-       if (!*num_names) {
+       if (!rids || !rids->count) {
                names = NULL;
                name_types = NULL;
                sid_mem = NULL;
                return NT_STATUS_OK;
        }
 
+       *num_names = rids->count;
+       rid_mem = rids->rids;
+
         /* Step #2: Convert list of rids into list of usernames.  Do this
            in bunches of ~1000 to avoid crashing NT4.  It looks like there
            is a buffer overflow or something like that lurking around