Function sigcheck_node_announcement

gossipd/sigcheck.c:118–164

Returns warning msg if signature wrong, else NULL */

/* Returns warning msg if signature wrong, else NULL */
const char *sigcheck_node_announcement(const tal_t *ctx,
				       const struct node_id *node_id,
				       const secp256k1_ecdsa_signature *signature,
				       const u8 *node_announcement)
{
	/* BOLT #7:
	 *
	 * 1. type: 257 (`node_announcement`)
	 * 2. data:
	 *    * [`signature`:`signature`]
	 *    * [`u16`:`flen`]
	 *    * [`flen*byte`:`features`]
	 *    * [`u32`:`timestamp`]
	 *    * [`point`:`node_id`]
	 *    * [`3*byte`:`rgb_color`]
	 *    * [`32*byte`:`alias`]
	 *    * [`u16`:`addrlen`]
	 *    * [`addrlen*byte`:`addresses`]
	 */
	/* 2 byte msg type + 64 byte signatures */
	int offset = 66;
	struct sha256_double hash;

	sha256_double(&hash, node_announcement + offset, tal_count(node_announcement) - offset);
	/* If node_id is invalid, it fails here */
	if (!check_signed_hash_nodeid(&hash, signature, node_id)) {
		/* BOLT #7:
		 *
		 * - if `signature` is not a valid signature, using
                 *   `node_id` of the double-SHA256 of the entire
                 *   message following the `signature` field
                 *   (including unknown fields following
                 *   `fee_proportional_millionths`):
                 *     - SHOULD send a `warning` and close the connection.
                 *     - MUST NOT process the message further.
		 */
		return tal_fmt(ctx,
			       "Bad signature for %s hash %s"
			       " on node_announcement %s",
			       fmt_secp256k1_ecdsa_signature(tmpctx,
							     signature),
			       fmt_sha256_double(tmpctx, &hash),
			       tal_hex(tmpctx, node_announcement));
	}

	return NULL;
}