Fix null pointer errors.

PR#3394

crypto/ocsp/ocsp_ht.c

@@ -571,6 +571,9 @@ OCSP_RESPONSE *OCSP_sendreq_bio(BIO *b, const char *path, OCSP_REQUEST *req)
 
 	ctx = OCSP_sendreq_new(b, path, req, -1);
 
+	if (!ctx)
+		return NULL;
+
 	do
 		{
 		rv = OCSP_sendreq_nbio(&resp, ctx);

ssl/d1_both.c

@@ -1051,6 +1051,8 @@ dtls1_buffer_message(SSL *s, int is_ccs)
 	OPENSSL_assert(s->init_off == 0);
 
 	frag = dtls1_hm_fragment_new(s->init_num, 0);
+	if (!frag)
+		return 0;
 
 	memcpy(frag->fragment, s->init_buf->data, s->init_num);