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5becfa6ee1
We had a scheme where lightningd itself would put a per-node secret in the blinded path, then we'd tell the caller when it was used. Then it simply checks the alias to determine if the correct path was used. But this doesn't work when we start to offer multiple blinded paths. So go for a far simpler scheme, where the secret is generated (and stored) by the caller, and hand it back to them. We keep the split "with secret" or "without secret" API, since I'm sure callers who don't care about the secret won't check that it doesn't exist! And without that, someone can use a blinded path for a different message and get a response which may reveal the node. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
/*~ This contains all the code to handle onion messages. */
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#include "config.h"
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#include <ccan/cast/cast.h>
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#include <common/blindedpath.h>
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#include <common/blinding.h>
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#include <common/daemon_conn.h>
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#include <common/ecdh_hsmd.h>
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#include <common/features.h>
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#include <common/onion_message_parse.h>
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#include <common/sphinx.h>
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#include <common/status.h>
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#include <common/type_to_string.h>
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#include <common/wire_error.h>
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#include <connectd/connectd.h>
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#include <connectd/connectd_wiregen.h>
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#include <connectd/multiplex.h>
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#include <connectd/onion_message.h>
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#include <wire/peer_wire.h>
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void onionmsg_req(struct daemon *daemon, const u8 *msg)
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{
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struct node_id id;
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u8 *onionmsg;
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struct pubkey blinding;
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struct peer *peer;
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if (!fromwire_connectd_send_onionmsg(msg, msg, &id, &onionmsg, &blinding))
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master_badmsg(WIRE_CONNECTD_SEND_ONIONMSG, msg);
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/* Even though lightningd checks for valid ids, there's a race
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* where it might vanish before we read this command. */
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peer = peer_htable_get(&daemon->peers, &id);
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if (peer) {
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u8 *omsg = towire_onion_message(NULL, &blinding, onionmsg);
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inject_peer_msg(peer, take(omsg));
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}
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}
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/* Peer sends an onion msg. */
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void handle_onion_message(struct daemon *daemon,
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struct peer *peer, const u8 *msg)
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{
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struct pubkey blinding;
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u8 *onion;
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u8 *next_onion_msg;
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struct pubkey next_node;
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struct tlv_onionmsg_tlv *final_om;
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struct pubkey final_alias;
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struct secret *final_path_id;
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/* Ignore unless explicitly turned on. */
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if (!feature_offered(daemon->our_features->bits[NODE_ANNOUNCE_FEATURE],
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OPT_ONION_MESSAGES))
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return;
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/* FIXME: ratelimit! */
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if (!fromwire_onion_message(msg, msg, &blinding, &onion)) {
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inject_peer_msg(peer,
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towire_warningfmt(NULL, NULL,
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"Bad onion_message"));
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return;
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}
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if (!onion_message_parse(tmpctx, onion, &blinding, &peer->id,
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&daemon->mykey,
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&next_onion_msg, &next_node,
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&final_om, &final_alias, &final_path_id))
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return;
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if (final_om) {
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u8 *omsg;
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/* We re-marshall here by policy, before handing to lightningd */
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omsg = tal_arr(tmpctx, u8, 0);
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towire_tlvstream_raw(&omsg, final_om->fields);
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daemon_conn_send(daemon->master,
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take(towire_connectd_got_onionmsg_to_us(NULL,
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final_path_id,
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final_om->reply_path,
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omsg)));
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} else {
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struct node_id next_node_id;
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struct peer *next_peer;
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assert(next_onion_msg);
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/* FIXME: Handle short_channel_id! */
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node_id_from_pubkey(&next_node_id, &next_node);
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next_peer = peer_htable_get(&daemon->peers, &next_node_id);
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if (!next_peer) {
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status_peer_debug(&peer->id,
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"onion msg: unknown next peer %s",
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type_to_string(tmpctx,
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struct pubkey,
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&next_node));
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return;
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}
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inject_peer_msg(next_peer, take(next_onion_msg));
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}
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}
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