Make CBB_finish() fail if *out_data is not NULL

Contrary to CBS_stow(), CBB_finish() will leak, so ensure we fail if
*out_data is populated.

Discussed with & ok jsing

1 files changed, 4 insertions, 1 deletions

diff --git a/src/lib/libssl/bs_cbb.c b/src/lib/libssl/bs_cbb.c
index 95e53861f0..e2f87be4d2 100644
--- a/src/lib/libssl/bs_cbb.c
+++ b/src/lib/libssl/bs_cbb.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bs_cbb.c,v 1.27 2022/01/06 14:30:30 jsing Exp $       */
+/*      $OpenBSD: bs_cbb.c,v 1.28 2022/07/07 17:12:15 tb Exp $  */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -163,6 +163,9 @@ CBB_finish(CBB *cbb, uint8_t **out_data, size_t *out_len)
                  */
                 return 0;
 
+        if (out_data != NULL && *out_data != NULL)
+                return 0;
+
         if (out_data != NULL)
                 *out_data = cbb->base->buf;