upstream: avoid possible NULL deref; from Pedro Martelletto

OpenBSD-Commit-ID: e6099c3fbb70aa67eb106e84d8b43f1fa919b721

diff --git a/ssh-keygen.c b/ssh-keygen.c
index bcf1ece39dcc49d1e1fca5bea77a391985cff353..405903319a563e7918979bcbd228ba7ae9fc0dcd 100644 (file)
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.410 2020/05/13 09:55:57 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.411 2020/05/18 04:29:35 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -2954,14 +2954,16 @@ 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 &&