commit 1b0d9bcc5f5cd78b0bb1357d6a11da5d616ad26f
Author: Wout Mertens <Wout.Mertens@gmail.com>
Date:   Thu Jun 11 18:08:13 2020 +0200

    fix segfault when using ECDSA keys.
    
    Author: Marc Deslauriers <marc.deslauriers@canonical.com>
    Bug-Ubuntu: https://bugs.launchpad.net/bugs/1869512

diff --git a/ssh-ecdsa.c b/ssh-ecdsa.c
index 5b13b30..5bf29cc 100644
--- a/ssh-ecdsa.c
+++ b/ssh-ecdsa.c
@@ -46,7 +46,7 @@ ssh_ecdsa_sign(const Key *key, u_char **sigp, u_int *lenp,
     u_int len, dlen;
     Buffer b, bb;
 #if OPENSSL_VERSION_NUMBER >= 0x10100005L
-	BIGNUM *r, *s;
+	BIGNUM *r = NULL, *s = NULL;
 #endif
 
     if (key == NULL || key->type != KEY_ECDSA || key->ecdsa == NULL) {
@@ -137,20 +137,27 @@ ssh_ecdsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
 
     /* parse signature */
     if ((sig = ECDSA_SIG_new()) == NULL)
-        pamsshagentauth_fatal("ssh_ecdsa_verify: DSA_SIG_new failed");
+        pamsshagentauth_fatal("ssh_ecdsa_verify: ECDSA_SIG_new failed");
 
     pamsshagentauth_buffer_init(&b);
     pamsshagentauth_buffer_append(&b, sigblob, len);
 #if OPENSSL_VERSION_NUMBER < 0x10100005L
     if ((pamsshagentauth_buffer_get_bignum2_ret(&b, sig->r) == -1) ||
         (pamsshagentauth_buffer_get_bignum2_ret(&b, sig->s) == -1))
+        pamsshagentauth_fatal("ssh_ecdsa_verify:"
+            "pamsshagentauth_buffer_get_bignum2_ret failed");
 #else
-    DSA_SIG_get0(sig, &r, &s);
+    if ((r = BN_new()) == NULL)
+        pamsshagentauth_fatal("ssh_ecdsa_verify: BN_new failed");
+    if ((s = BN_new()) == NULL)
+        pamsshagentauth_fatal("ssh_ecdsa_verify: BN_new failed");
     if ((pamsshagentauth_buffer_get_bignum2_ret(&b, r) == -1) ||
         (pamsshagentauth_buffer_get_bignum2_ret(&b, s) == -1))
-#endif
         pamsshagentauth_fatal("ssh_ecdsa_verify:"
             "pamsshagentauth_buffer_get_bignum2_ret failed");
+    if (ECDSA_SIG_set0(sig, r, s) != 1)
+        pamsshagentauth_fatal("ssh_ecdsa_verify: ECDSA_SIG_set0 failed");
+#endif
 
     /* clean up */
     memset(sigblob, 0, len);