upstream: avoid possible NULL deref; from Pedro Martelletto

OpenBSD-Commit-ID: e6099c3fbb70aa67eb106e84d8b43f1fa919b721

1 files changed, 5 insertions, 3 deletions

diff --git a/ssh-keygen.c b/ssh-keygen.c
index 8c23a54cf..2c5c75db7 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.409 2020/05/02 07:19:43 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.409.2.1 2020/05/18 19:02:13 benno Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -2950,14 +2950,16 @@ do_download_sk(const char *skprovider, const char *device)
                     &keys, &nkeys)) != 0) {
                         if (i == 0 && r == SSH_ERR_KEY_WRONG_PASSPHRASE)
                                 continue;
-                        freezero(pin, strlen(pin));
+                        if (pin != NULL)
+                                freezero(pin, strlen(pin));
                         error("Unable to load resident keys: %s", ssh_err(r));
                         return -1;
                 }
         }
         if (nkeys == 0)
                 logit("No keys to download");
-        freezero(pin, strlen(pin));
+        if (pin != NULL)
+                freezero(pin, strlen(pin));
 
         for (i = 0; i < nkeys; i++) {
                 if (keys[i]->type != KEY_ECDSA_SK &&