upstream: check sig_r and sig_s for ssh-sk keys; ok djm

OpenBSD-Commit-ID: 1a1e6a85b5f465d447a3800f739e35c5b74e0abc

diff --git a/ssh-sk.c b/ssh-sk.c
index a9da765ebfbaee79bf5749d3428f0c56c888d949..7a4bf8c6b5c9681ce671b87891085623874a6723 100644 (file)
--- a/ssh-sk.c
+++ b/ssh-sk.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk.c,v 1.7 2019/11/12 19:32:30 markus Exp $ */
+/* $OpenBSD: ssh-sk.c,v 1.8 2019/11/12 19:34:00 markus Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -365,6 +365,12 @@ sshsk_ecdsa_inner_sig(struct sk_sign_response *resp, struct sshbuf **retp)
        int r = SSH_ERR_INTERNAL_ERROR;
 
        *retp = NULL;
+       /* Check response validity */
+       if (resp->sig_r == NULL || resp->sig_r == NULL) {
+               error("%s: sk_sign response invalid", __func__);
+               r = SSH_ERR_INVALID_FORMAT;
+               goto out;
+       }
        if ((inner_sig = sshbuf_new()) == NULL) {
                r = SSH_ERR_ALLOC_FAIL;
                goto out;
@@ -400,6 +406,12 @@ sshsk_ed25519_inner_sig(struct sk_sign_response *resp, struct sshbuf **retp)
        int r = SSH_ERR_INTERNAL_ERROR;
 
        *retp = NULL;
+       /* Check response validity */
+       if (resp->sig_r == NULL) {
+               error("%s: sk_sign response invalid", __func__);
+               r = SSH_ERR_INVALID_FORMAT;
+               goto out;
+       }
        if ((inner_sig = sshbuf_new()) == NULL) {
                r = SSH_ERR_ALLOC_FAIL;
                goto out;