Add missing NULL check in X509V3_parse_list()

Matt's note: I added a call to X509V3err to Kurt's original patch.

RT#3840
Signed-off-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/x509v3/v3_utl.c

@@ -286,6 +286,10 @@ 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) {
+        X509V3err(X509V3_F_X509V3_PARSE_LIST, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
     state = HDR_NAME;
     ntmp = NULL;
     /* Go through all characters */