src: improve error handling in CloneSSLCerts

If sk_X509_new() returns NULL or if sk_X509_push() fails, return instead
of silently ignoring the error.

Author: tniessen

src/crypto/crypto_common.cc

@@ -323,8 +323,10 @@ constexpr auto GetCipherVersion = GetCipherValue<SSL_CIPHER_get_version>;
 StackOfX509 CloneSSLCerts(X509Pointer&& cert,
                           const STACK_OF(X509)* const ssl_certs) {
   StackOfX509 peer_certs(sk_X509_new(nullptr));
-  if (cert)
-    sk_X509_push(peer_certs.get(), cert.release());
+  if (!peer_certs)
+    return StackOfX509();
+  if (cert && !sk_X509_push(peer_certs.get(), cert.release()))
+    return StackOfX509();
   for (int i = 0; i < sk_X509_num(ssl_certs); i++) {
     X509Pointer cert(X509_dup(sk_X509_value(ssl_certs, i)));
     if (!cert || !sk_X509_push(peer_certs.get(), cert.get()))