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common/onion_message_parse: generic routine for parsing onion messages.
Instead of open coding in connectd/onion_message, we move it to common with a nice API. This lets us process the BOLT test vectors. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
parent
5cf86a1a2e
commit
159fc7d1a2
@ -59,6 +59,7 @@ COMMON_SRC_NOGEN := \
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common/node_id.c \
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common/onion.c \
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common/onionreply.c \
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common/onion_message_parse.c \
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common/peer_billboard.c \
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common/peer_failed.c \
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common/peer_io.c \
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187
common/onion_message_parse.c
Normal file
187
common/onion_message_parse.c
Normal file
@ -0,0 +1,187 @@
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/* Caller does fromwire_onion_message(), this does the rest. */
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#include "config.h"
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#include <assert.h>
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#include <common/blindedpath.h>
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#include <common/ecdh.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/utils.h>
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#include <wire/onion_wire.h>
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#include <wire/peer_wire.h>
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static bool decrypt_final_onionmsg(const tal_t *ctx,
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const struct pubkey *blinding,
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const struct secret *ss,
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const u8 *enctlv,
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const struct pubkey *my_id,
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struct pubkey *alias,
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struct secret **path_id)
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{
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struct tlv_encrypted_data_tlv *encmsg;
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if (!blindedpath_get_alias(ss, my_id, alias))
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return false;
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encmsg = decrypt_encrypted_data(tmpctx, blinding, ss, enctlv);
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if (!encmsg)
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return false;
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if (tal_bytelen(encmsg->path_id) == sizeof(**path_id)) {
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*path_id = tal(ctx, struct secret);
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memcpy(*path_id, encmsg->path_id, sizeof(**path_id));
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} else
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*path_id = NULL;
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return true;
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}
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static bool decrypt_forwarding_onionmsg(const struct pubkey *blinding,
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const struct secret *ss,
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const u8 *enctlv,
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struct pubkey *next_node,
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struct pubkey *next_blinding)
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{
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struct tlv_encrypted_data_tlv *encmsg;
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encmsg = decrypt_encrypted_data(tmpctx, blinding, ss, enctlv);
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if (!encmsg)
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return false;
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/* BOLT-onion-message #4:
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*
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* The reader:
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* - if it is not the final node according to the onion encryption:
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*...
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* - if the `enctlv` ... does not contain
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* `next_node_id`:
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* - MUST drop the message.
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*/
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if (!encmsg->next_node_id)
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return false;
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/* BOLT-onion-message #4:
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* The reader:
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* - if it is not the final node according to the onion encryption:
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*...
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* - if the `enctlv` contains `path_id`:
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* - MUST drop the message.
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*/
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if (encmsg->path_id)
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return false;
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*next_node = *encmsg->next_node_id;
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blindedpath_next_blinding(encmsg, blinding, ss, next_blinding);
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return true;
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}
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/* Returns false on failure */
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bool onion_message_parse(const tal_t *ctx,
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const u8 *onion_message_packet,
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const struct pubkey *blinding,
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const struct node_id *peer,
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const struct pubkey *me,
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u8 **next_onion_msg,
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struct pubkey *next_node_id,
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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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{
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enum onion_wire badreason;
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struct onionpacket *op;
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struct pubkey ephemeral;
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struct route_step *rs;
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struct tlv_onionmsg_tlv *om;
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struct secret ss, onion_ss;
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const u8 *cursor;
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size_t max, maxlen;
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/* We unwrap the onion now. */
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op = parse_onionpacket(tmpctx,
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onion_message_packet,
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tal_bytelen(onion_message_packet),
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&badreason);
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if (!op) {
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status_peer_debug(peer, "onion_message_parse: can't parse onionpacket: %s",
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onion_wire_name(badreason));
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return false;
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}
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ephemeral = op->ephemeralkey;
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if (!unblind_onion(blinding, ecdh, &ephemeral, &ss)) {
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status_peer_debug(peer, "onion_message_parse: can't unblind onionpacket");
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return false;
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}
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/* Now get onion shared secret and parse it. */
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ecdh(&ephemeral, &onion_ss);
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rs = process_onionpacket(tmpctx, op, &onion_ss, NULL, 0, false);
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if (!rs) {
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status_peer_debug(peer,
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"onion_message_parse: can't process onionpacket ss=%s",
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type_to_string(tmpctx, struct secret, &onion_ss));
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return false;
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}
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/* The raw payload is prepended with length in the modern onion. */
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cursor = rs->raw_payload;
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max = tal_bytelen(rs->raw_payload);
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maxlen = fromwire_bigsize(&cursor, &max);
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if (!cursor) {
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status_peer_debug(peer, "onion_message_parse: Invalid hop payload %s",
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tal_hex(tmpctx, rs->raw_payload));
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return false;
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}
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if (maxlen > max) {
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status_peer_debug(peer, "onion_message_parse: overlong hop payload %s",
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tal_hex(tmpctx, rs->raw_payload));
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return false;
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}
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om = fromwire_tlv_onionmsg_tlv(tmpctx, &cursor, &maxlen);
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if (!om) {
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status_peer_debug(peer, "onion_message_parse: invalid onionmsg_tlv %s",
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tal_hex(tmpctx, rs->raw_payload));
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return false;
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}
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if (rs->nextcase == ONION_END) {
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*next_onion_msg = NULL;
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*final_om = tal_steal(ctx, om);
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/* Final enctlv is actually optional */
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if (!om->encrypted_recipient_data) {
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*final_alias = *me;
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*final_path_id = NULL;
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} else if (!decrypt_final_onionmsg(ctx, blinding, &ss,
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om->encrypted_recipient_data, me,
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final_alias,
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final_path_id)) {
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status_peer_debug(peer,
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"onion_message_parse: failed to decrypt encrypted_recipient_data"
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" %s", tal_hex(tmpctx, om->encrypted_recipient_data));
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return false;
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}
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} else {
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struct pubkey next_blinding;
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*final_om = NULL;
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/* This fails as expected if no enctlv. */
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if (!decrypt_forwarding_onionmsg(blinding, &ss, om->encrypted_recipient_data, next_node_id,
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&next_blinding)) {
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status_peer_debug(peer,
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"onion_message_parse: invalid encrypted_recipient_data %s",
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tal_hex(tmpctx, om->encrypted_recipient_data));
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return false;
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}
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*next_onion_msg = towire_onion_message(ctx,
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&next_blinding,
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serialize_onionpacket(tmpctx, rs->next));
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}
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/* Exactly one is set */
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assert(!*next_onion_msg + !*final_om == 1);
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return true;
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}
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37
common/onion_message_parse.h
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37
common/onion_message_parse.h
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@ -0,0 +1,37 @@
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#ifndef LIGHTNING_COMMON_ONION_MESSAGE_PARSE_H
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#define LIGHTNING_COMMON_ONION_MESSAGE_PARSE_H
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#include "config.h"
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#include <bitcoin/privkey.h>
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#include <common/amount.h>
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struct tlv_onionmsg_tlv;
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struct node_id;
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struct pubkey;
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/**
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* onion_message_parse: core routine to check onion_message
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* @ctx: context to allocate @next_onion_msg or @final_om/@path_id off
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* @onion_message_packet: Sphinx-encrypted onion
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* @blinding: Blinding we were given for @onion_message_packet
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* @peer: node_id of peer (for status_peer_debug msgs)
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* @me: my pubkey
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* @next_onion_msg (out): set if we should forward, otherwise NULL.
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* @next_node_id (out): set to node id to fwd to, iff *@next_onion_msg.
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* @final_om (out): set if we're the final hop, otherwise NULL.
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* @final_alias (out): our alias (if *@final_om), or our own ID
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* @final_path_id (out): secret enclosed, if any (iff *@final_om).
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*
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* Returns false if it wasn't valid.
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*/
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bool onion_message_parse(const tal_t *ctx,
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const u8 *onion_message_packet,
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const struct pubkey *blinding,
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const struct node_id *peer,
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const struct pubkey *me,
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u8 **next_onion_msg,
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struct pubkey *next_node_id,
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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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#endif /* LIGHTNING_COMMON_ONION_MESSAGE_PARSE_H */
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@ -62,6 +62,7 @@ CONNECTD_COMMON_OBJS := \
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common/node_id.o \
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common/onion.o \
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common/onionreply.o \
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common/onion_message_parse.o \
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common/ping.o \
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common/per_peer_state.o \
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common/psbt_open.o \
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@ -6,6 +6,7 @@
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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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@ -35,84 +36,17 @@ void onionmsg_req(struct daemon *daemon, const u8 *msg)
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}
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}
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static bool decrypt_final_onionmsg(const tal_t *ctx,
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const struct pubkey *blinding,
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const struct secret *ss,
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const u8 *enctlv,
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const struct pubkey *my_id,
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struct pubkey *alias,
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struct secret **path_id)
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{
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struct tlv_encrypted_data_tlv *encmsg;
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if (!blindedpath_get_alias(ss, my_id, alias))
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return false;
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encmsg = decrypt_encrypted_data(tmpctx, blinding, ss, enctlv);
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if (!encmsg)
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return false;
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if (tal_bytelen(encmsg->path_id) == sizeof(**path_id)) {
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*path_id = tal(ctx, struct secret);
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memcpy(*path_id, encmsg->path_id, sizeof(**path_id));
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} else
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*path_id = NULL;
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return true;
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}
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static bool decrypt_forwarding_onionmsg(const struct pubkey *blinding,
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const struct secret *ss,
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const u8 *enctlv,
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struct pubkey *next_node,
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struct pubkey *next_blinding)
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{
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struct tlv_encrypted_data_tlv *encmsg;
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encmsg = decrypt_encrypted_data(tmpctx, blinding, ss, enctlv);
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if (!encmsg)
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return false;
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/* BOLT-onion-message #4:
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*
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* The reader:
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* - if it is not the final node according to the onion encryption:
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*...
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* - if the `enctlv` ... does not contain
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* `next_node_id`:
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* - MUST drop the message.
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*/
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if (!encmsg->next_node_id)
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return false;
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/* BOLT-onion-message #4:
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* The reader:
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* - if it is not the final node according to the onion encryption:
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*...
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* - if the `enctlv` contains `path_id`:
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* - MUST drop the message.
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*/
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if (encmsg->path_id)
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return false;
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*next_node = *encmsg->next_node_id;
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blindedpath_next_blinding(encmsg, blinding, ss, next_blinding);
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return true;
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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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enum onion_wire badreason;
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struct onionpacket *op;
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struct pubkey blinding, ephemeral;
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struct route_step *rs;
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struct pubkey blinding;
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u8 *onion;
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struct tlv_onionmsg_tlv *om;
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struct secret ss, onion_ss;
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const u8 *cursor;
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size_t max, maxlen;
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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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@ -127,91 +61,28 @@ void handle_onion_message(struct daemon *daemon,
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return;
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}
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/* We unwrap the onion now. */
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op = parse_onionpacket(tmpctx, onion, tal_bytelen(onion), &badreason);
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if (!op) {
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status_peer_debug(&peer->id, "onion msg: can't parse onionpacket: %s",
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onion_wire_name(badreason));
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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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}
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ephemeral = op->ephemeralkey;
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if (!unblind_onion(&blinding, ecdh, &ephemeral, &ss)) {
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status_peer_debug(&peer->id, "onion msg: can't unblind onionpacket");
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return;
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}
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/* Now get onion shared secret and parse it. */
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ecdh(&ephemeral, &onion_ss);
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rs = process_onionpacket(tmpctx, op, &onion_ss, NULL, 0, false);
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if (!rs) {
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status_peer_debug(&peer->id,
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"onion msg: can't process onionpacket ss=%s",
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type_to_string(tmpctx, struct secret, &onion_ss));
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return;
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}
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/* The raw payload is prepended with length in the modern onion. */
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cursor = rs->raw_payload;
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max = tal_bytelen(rs->raw_payload);
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maxlen = fromwire_bigsize(&cursor, &max);
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if (!cursor) {
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status_peer_debug(&peer->id, "onion msg: Invalid hop payload %s",
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tal_hex(tmpctx, rs->raw_payload));
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return;
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}
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if (maxlen > max) {
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status_peer_debug(&peer->id, "onion msg: overlong hop payload %s",
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tal_hex(tmpctx, rs->raw_payload));
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return;
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}
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om = fromwire_tlv_onionmsg_tlv(msg, &cursor, &maxlen);
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if (!om) {
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status_peer_debug(&peer->id, "onion msg: invalid onionmsg_tlv %s",
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tal_hex(tmpctx, rs->raw_payload));
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return;
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}
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if (rs->nextcase == ONION_END) {
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struct pubkey alias;
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struct secret *self_id;
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if (final_om) {
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u8 *omsg;
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/* Final enctlv is actually optional */
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if (!om->encrypted_recipient_data) {
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alias = daemon->mykey;
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self_id = NULL;
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} else if (!decrypt_final_onionmsg(tmpctx, &blinding, &ss,
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om->encrypted_recipient_data, &daemon->mykey, &alias,
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&self_id)) {
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status_peer_debug(&peer->id,
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"onion msg: failed to decrypt encrypted_recipient_data"
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" %s", tal_hex(tmpctx, om->encrypted_recipient_data));
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return;
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}
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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, om->fields);
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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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&alias, self_id,
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om->reply_path,
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&final_alias, 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 pubkey next_node, next_blinding;
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struct peer *next_peer;
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struct node_id next_node_id;
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struct peer *next_peer;
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/* This fails as expected if no enctlv. */
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if (!decrypt_forwarding_onionmsg(&blinding, &ss, om->encrypted_recipient_data, &next_node,
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&next_blinding)) {
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status_peer_debug(&peer->id,
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"onion msg: invalid encrypted_recipient_data %s",
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tal_hex(tmpctx, om->encrypted_recipient_data));
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return;
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}
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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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@ -224,10 +95,7 @@ void handle_onion_message(struct daemon *daemon,
|
||||
&next_node));
|
||||
return;
|
||||
}
|
||||
inject_peer_msg(next_peer,
|
||||
take(towire_onion_message(NULL,
|
||||
&next_blinding,
|
||||
serialize_onionpacket(tmpctx, rs->next))));
|
||||
inject_peer_msg(next_peer, take(next_onion_msg));
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user