Add missing BUF_strdup failure checks.

Change-Id: I997e8806b0bccb58fe7b8bbea4e98c68d0925361
Reviewed-on: https://boringssl-review.googlesource.com/4513
Reviewed-by: Adam Langley <agl@google.com>

crypto/bio/connect.c

@@ -430,11 +430,17 @@ static long conn_ctrl(BIO *bio, int cmd, long num, void *ptr) {
             OPENSSL_free(data->param_hostname);
           }
           data->param_hostname = BUF_strdup(ptr);
+          if (data->param_hostname == NULL) {
+            ret = 0;
+          }
         } else if (num == 1) {
           if (data->param_port != NULL) {
             OPENSSL_free(data->param_port);
           }
           data->param_port = BUF_strdup(ptr);
+          if (data->param_port == NULL) {
+            ret = 0;
+          }
         } else {
           ret = 0;
         }

crypto/x509v3/v3_utl.c

@@ -262,6 +262,8 @@ STACK_OF(CONF_VALUE) *X509V3_parse_list(const char *line)
 	int state;
 	/* We are going to modify the line so copy it first */
 	linebuf = BUF_strdup(line);
+	if (linebuf == NULL)
+		goto err;
 	state = HDR_NAME;
 	ntmp = NULL;
 	/* Go through all characters */