core-lightning/lightningd/onion_message.c
Rusty Russell b8498b60f2 lightningd: blindedpath helper to create a blinded path to ourselves.
Currently it will be used for onion replies, but we can use it for offers
and invoices in future, if we want to avoid revealing our node_id.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2021-09-22 09:10:34 +09:30

683 lines
20 KiB
C

#include <common/blindedpath.h>
#include <common/json_command.h>
#include <common/json_helpers.h>
#include <common/json_tok.h>
#include <common/param.h>
#include <common/type_to_string.h>
#include <gossipd/gossipd_wiregen.h>
#include <lightningd/channel.h>
#include <lightningd/json.h>
#include <lightningd/onion_message.h>
#include <lightningd/peer_control.h>
#include <lightningd/plugin_hook.h>
#include <lightningd/subd.h>
#include <sodium/randombytes.h>
struct onion_message_hook_payload {
/* Optional */
struct pubkey *blinding_in;
struct pubkey *reply_blinding;
struct onionmsg_path **reply_path;
struct tlv_onionmsg_payload *om;
};
static void json_add_blindedpath(struct json_stream *stream,
const char *fieldname,
const struct pubkey *blinding,
const struct pubkey *first_node_id,
struct onionmsg_path **path)
{
json_object_start(stream, fieldname);
json_add_pubkey(stream, "blinding", blinding);
json_add_pubkey(stream, "first_node_id", first_node_id);
json_array_start(stream, "hops");
for (size_t i = 0; i < tal_count(path); i++) {
json_object_start(stream, NULL);
json_add_pubkey(stream, "id", &path[i]->node_id);
json_add_hex_talarr(stream, "enctlv", path[i]->enctlv);
json_object_end(stream);
};
json_array_end(stream);
json_object_end(stream);
}
static void onion_message_serialize(struct onion_message_hook_payload *payload,
struct json_stream *stream,
struct plugin *plugin)
{
json_object_start(stream, "onion_message");
if (payload->blinding_in)
json_add_pubkey(stream, "blinding_in", payload->blinding_in);
if (payload->reply_path) {
json_array_start(stream, "reply_path");
for (size_t i = 0; i < tal_count(payload->reply_path); i++) {
json_object_start(stream, NULL);
json_add_pubkey(stream, "id",
&payload->reply_path[i]->node_id);
if (tal_bytelen(payload->reply_path[i]->enctlv) != 0)
json_add_hex_talarr(stream, "enctlv",
payload->reply_path[i]->enctlv);
if (i == 0)
json_add_pubkey(stream, "blinding",
payload->reply_blinding);
json_object_end(stream);
}
json_array_end(stream);
}
/* Common convenience fields */
if (payload->om->invoice_request)
json_add_hex_talarr(stream, "invoice_request",
payload->om->invoice_request);
if (payload->om->invoice)
json_add_hex_talarr(stream, "invoice", payload->om->invoice);
if (payload->om->invoice_error)
json_add_hex_talarr(stream, "invoice_error",
payload->om->invoice_error);
json_array_start(stream, "unknown_fields");
for (size_t i = 0; i < tal_count(payload->om->fields); i++) {
if (payload->om->fields[i].meta)
continue;
json_object_start(stream, NULL);
json_add_u64(stream, "number", payload->om->fields[i].numtype);
json_add_hex(stream, "value",
payload->om->fields[i].value,
payload->om->fields[i].length);
json_object_end(stream);
}
json_array_end(stream);
json_object_end(stream);
}
static void
onion_message_hook_cb(struct onion_message_hook_payload *payload STEALS)
{
/* plugin_hook_continue checks the "result"; anything other than continue
* just stops. */
tal_free(payload);
}
/* Two hooks, because it's critical we only accept blinding if we expect that
* exact blinding key. Otherwise, we can be probed using old blinded paths. */
REGISTER_PLUGIN_HOOK(onion_message,
plugin_hook_continue,
onion_message_hook_cb,
onion_message_serialize,
struct onion_message_hook_payload *);
REGISTER_PLUGIN_HOOK(onion_message_blinded,
plugin_hook_continue,
onion_message_hook_cb,
onion_message_serialize,
struct onion_message_hook_payload *);
void handle_obs_onionmsg_to_us(struct lightningd *ld, const u8 *msg)
{
struct onion_message_hook_payload *payload;
u8 *submsg;
size_t submsglen;
const u8 *subptr;
payload = tal(ld, struct onion_message_hook_payload);
payload->om = tlv_onionmsg_payload_new(payload);
if (!fromwire_gossipd_got_obs_onionmsg_to_us(payload, msg,
&payload->blinding_in,
&payload->reply_blinding,
&payload->reply_path,
&submsg)) {
log_broken(ld->log, "bad got_onionmsg_tous: %s",
tal_hex(tmpctx, msg));
return;
}
submsglen = tal_bytelen(submsg);
subptr = submsg;
if (!fromwire_onionmsg_payload(&subptr,
&submsglen, payload->om)) {
tal_free(payload);
log_broken(ld->log, "bad got_onionmsg_tous om: %s",
tal_hex(tmpctx, msg));
return;
}
tal_free(submsg);
if (payload->reply_path && !payload->reply_blinding) {
log_broken(ld->log,
"No reply blinding, ignoring reply path");
payload->reply_path = tal_free(payload->reply_path);
}
log_debug(ld->log, "Got obsolete onionmsg%s%s",
payload->reply_blinding ? " reply_blinding": "",
payload->reply_path ? " reply_path": "");
if (payload->blinding_in)
plugin_hook_call_onion_message_blinded(ld, payload);
else
plugin_hook_call_onion_message(ld, payload);
}
void handle_obs_onionmsg_forward(struct lightningd *ld, const u8 *msg)
{
struct short_channel_id *next_scid;
struct node_id *next_node;
struct pubkey *next_blinding;
u8 *onion;
if (!fromwire_gossipd_got_obs_onionmsg_forward(msg, msg, &next_scid,
&next_node,
&next_blinding, &onion)) {
log_broken(ld->log, "bad got_onionmsg_forward: %s",
tal_hex(tmpctx, msg));
return;
}
if (next_scid) {
struct channel *outchan = any_channel_by_scid(ld, next_scid);
if (outchan)
next_node = &outchan->peer->id;
}
if (!next_node) {
log_debug(ld->log, "Cannot forward onionmsg to %s",
next_scid ? type_to_string(tmpctx,
struct short_channel_id,
next_scid)
: "unspecified dest");
} else {
subd_send_msg(ld->gossip,
take(towire_gossipd_send_obs_onionmsg(NULL,
next_node,
onion,
next_blinding)));
}
}
void handle_onionmsg_to_us(struct lightningd *ld, const u8 *msg)
{
/* FIXME! */
return;
}
struct hop {
struct pubkey id;
struct short_channel_id *scid;
struct pubkey *blinding;
u8 *enctlv;
u8 *invoice;
u8 *invoice_req;
u8 *invoice_err;
u8 *rawtlv;
};
static struct command_result *param_hops(struct command *cmd,
const char *name,
const char *buffer,
const jsmntok_t *tok,
struct hop **hops)
{
size_t i;
const jsmntok_t *t;
if (tok->type != JSMN_ARRAY || tok->size == 0)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s must be an (non-empty) array", name);
*hops = tal_arr(cmd, struct hop, tok->size);
json_for_each_arr(i, t, tok) {
const jsmntok_t *tid, *tscid, *tblinding, *tenctlv, *trawtlv,
*tinvoice, *tinvoicereq, *tinvoiceerr;
tid = json_get_member(buffer, t, "id");
if (!tid)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] does not have 'id'",
name, i);
tscid = json_get_member(buffer, t, "short_channel_id");
tblinding = json_get_member(buffer, t, "blinding");
tenctlv = json_get_member(buffer, t, "enctlv");
tinvoice = json_get_member(buffer, t, "invoice");
tinvoicereq = json_get_member(buffer, t, "invoice_request");
tinvoiceerr = json_get_member(buffer, t, "invoice_error");
trawtlv = json_get_member(buffer, t, "rawtlv");
if (trawtlv && (tscid || tblinding || tenctlv || tinvoice || tinvoicereq))
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] has 'rawtlv' with other fields",
name, i);
if (tblinding) {
(*hops)[i].blinding = tal(*hops, struct pubkey);
if (!json_to_pubkey(buffer, tblinding,
(*hops)[i].blinding))
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'blinding' is invalid", name, i);
} else
(*hops)[i].blinding = NULL;
if (!json_to_pubkey(buffer, tid, &(*hops)[i].id))
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'id' is invalid", name, i);
if (tscid) {
(*hops)[i].scid = tal(*hops, struct short_channel_id);
if (!json_to_short_channel_id(buffer, tscid,
(*hops)[i].scid))
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'short_channel_id' is invalid", name, i);
} else
(*hops)[i].scid = NULL;
if (tenctlv) {
(*hops)[i].enctlv =
json_tok_bin_from_hex(*hops, buffer, tenctlv);
if (!(*hops)[i].enctlv)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'enctlv' is invalid", name, i);
} else
(*hops)[i].enctlv = NULL;
if (tinvoice) {
(*hops)[i].invoice =
json_tok_bin_from_hex(*hops, buffer, tinvoice);
if (!(*hops)[i].invoice)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'invoice' is invalid", name, i);
} else
(*hops)[i].invoice = NULL;
if (tinvoicereq) {
(*hops)[i].invoice_req =
json_tok_bin_from_hex(*hops, buffer, tinvoicereq);
if (!(*hops)[i].invoice_req)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'invoice_request' is invalid", name, i);
} else
(*hops)[i].invoice_req = NULL;
if (tinvoiceerr) {
(*hops)[i].invoice_err =
json_tok_bin_from_hex(*hops, buffer, tinvoiceerr);
if (!(*hops)[i].invoice_err)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'invoice_request' is invalid", name, i);
} else
(*hops)[i].invoice_err = NULL;
if (trawtlv) {
(*hops)[i].rawtlv =
json_tok_bin_from_hex(*hops, buffer, trawtlv);
if (!(*hops)[i].rawtlv)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu] 'rawtlv' is invalid", name, i);
} else
(*hops)[i].rawtlv = NULL;
}
return NULL;
}
static struct command_result *param_reply_path(struct command *cmd,
const char *name,
const char *buffer,
const jsmntok_t *tok,
struct tlv_onionmsg_payload_obs_reply_path **reply_path)
{
const jsmntok_t *tblinding, *tpath, *t;
size_t i;
*reply_path = tal(cmd, struct tlv_onionmsg_payload_obs_reply_path);
tblinding = json_get_member(buffer, tok, "blinding");
if (!tblinding)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s has no 'blinding'", name);
if (!json_to_pubkey(buffer, tblinding, &(*reply_path)->blinding))
return command_fail_badparam(cmd, name, buffer, tblinding,
"'blinding' should be valid pubkey");
tpath = json_get_member(buffer, tok, "path");
if (!tpath || tpath->type != JSMN_ARRAY)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s has no 'path' array", name);
(*reply_path)->path = tal_arr(*reply_path, struct onionmsg_path *,
tpath->size);
json_for_each_arr(i, t, tpath) {
const jsmntok_t *tid, *tenctlv;
struct onionmsg_path *path;
path = (*reply_path)->path[i] = tal((*reply_path)->path,
struct onionmsg_path);
tid = json_get_member(buffer, t, "id");
if (!tid)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s path[%zu] 'id' is missing",
name, i);
if (!json_to_pubkey(buffer, tid, &path->node_id))
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s path[%zu] 'id' is invalid",
name, i);
tenctlv = json_get_member(buffer, t, "enctlv");
if (!tenctlv) {
/* Optional for final destination */
if (i != tpath->size - 1)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s path[%zu] 'enctlv' is missing",
name, i);
path->enctlv = NULL;
} else {
path->enctlv = json_tok_bin_from_hex(path,
buffer, tenctlv);
if (!path->enctlv)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s path[%zu] 'enctlv' is invalid",
name, i);
}
}
return NULL;
}
/* Generate ->rawtlv if not already supplied. */
static void populate_tlvs(struct hop *hops,
struct tlv_onionmsg_payload_obs_reply_path *reply_path)
{
for (size_t i = 0; i < tal_count(hops); i++) {
struct tlv_onionmsg_payload *tlv;
if (hops[i].rawtlv)
continue;
tlv = tlv_onionmsg_payload_new(tmpctx);
/* If they don't give scid, use next node id */
if (hops[i].scid) {
tlv->obs_next_short_channel_id
= tal_dup(tlv, struct short_channel_id,
hops[i].scid);
} else if (i != tal_count(hops)-1) {
tlv->obs_next_node_id = tal_dup(tlv, struct pubkey,
&hops[i+1].id);
}
if (hops[i].blinding) {
tlv->obs_blinding = tal_dup(tlv, struct pubkey,
hops[i].blinding);
}
/* Note: tal_dup_talarr returns NULL for NULL */
tlv->enctlv = tal_dup_talarr(tlv, u8, hops[i].enctlv);
tlv->invoice = tal_dup_talarr(tlv, u8, hops[i].invoice);
tlv->invoice_request = tal_dup_talarr(tlv, u8,
hops[i].invoice_req);
tlv->invoice_error = tal_dup_talarr(tlv, u8,
hops[i].invoice_err);
if (i == tal_count(hops)-1 && reply_path)
tlv->obs_reply_path = reply_path;
hops[i].rawtlv = tal_arr(hops, u8, 0);
towire_onionmsg_payload(&hops[i].rawtlv, tlv);
}
}
static struct command_result *json_send_obs_onion_message(struct command *cmd,
const char *buffer,
const jsmntok_t *obj UNNEEDED,
const jsmntok_t *params)
{
struct hop *hops;
struct tlv_onionmsg_payload_obs_reply_path *reply_path;
struct sphinx_path *sphinx_path;
struct onionpacket *op;
struct secret *path_secrets;
struct node_id first_id;
size_t onion_size;
if (!param(cmd, buffer, params,
p_req("hops", param_hops, &hops),
p_opt("reply_path", param_reply_path, &reply_path),
NULL))
return command_param_failed();
if (!feature_offered(cmd->ld->our_features->bits[NODE_ANNOUNCE_FEATURE],
OPT_ONION_MESSAGES))
return command_fail(cmd, LIGHTNINGD,
"experimental-onion-messages not enabled");
node_id_from_pubkey(&first_id, &hops[0].id);
/* Sanity check first; gossipd doesn't bother telling us if peer
* can't be reached. */
if (!peer_by_id(cmd->ld, &first_id))
return command_fail(cmd, LIGHTNINGD, "Unknown first peer");
/* Create an onion which encodes this. */
populate_tlvs(hops, reply_path);
sphinx_path = sphinx_path_new(cmd, NULL);
for (size_t i = 0; i < tal_count(hops); i++)
sphinx_add_modern_hop(sphinx_path, &hops[i].id, hops[i].rawtlv);
/* BOLT-onion-message #4:
* - SHOULD set `len` to 1366 or 32834.
*/
if (sphinx_path_payloads_size(sphinx_path) <= ROUTING_INFO_SIZE)
onion_size = ROUTING_INFO_SIZE;
else
onion_size = 32768;
op = create_onionpacket(tmpctx, sphinx_path, onion_size, &path_secrets);
if (!op)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"Creating onion failed (tlvs too long?)");
subd_send_msg(cmd->ld->gossip,
take(towire_gossipd_send_obs_onionmsg(NULL, &first_id,
serialize_onionpacket(tmpctx, op),
NULL)));
return command_success(cmd, json_stream_success(cmd));
}
static const struct json_command send_obs_onion_message_command = {
"sendobsonionmessage",
"utility",
json_send_obs_onion_message,
"Send message over {hops} (id, [short_channel_id], [blinding], [enctlv], [invoice], [invoice_request], [invoice_error], [rawtlv]) with optional {reply_path} (blinding, path[id, enctlv])"
};
AUTODATA(json_command, &send_obs_onion_message_command);
struct onion_hop {
struct pubkey node;
u8 *tlv;
};
static struct command_result *param_onion_hops(struct command *cmd,
const char *name,
const char *buffer,
const jsmntok_t *tok,
struct onion_hop **hops)
{
size_t i;
const jsmntok_t *t;
if (tok->type != JSMN_ARRAY || tok->size == 0)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s must be an (non-empty) array", name);
*hops = tal_arr(cmd, struct onion_hop, tok->size);
json_for_each_arr(i, t, tok) {
const char *err;
err = json_scan(cmd, buffer, t, "{id:%,tlv:%}",
JSON_SCAN(json_to_pubkey, &(*hops)[i].node),
JSON_SCAN_TAL(tmpctx, json_tok_bin_from_hex,
&(*hops)[i].tlv));
if (err)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s[%zu]: %s", name, i, err);
}
return NULL;
}
static struct command_result *json_sendonionmessage(struct command *cmd,
const char *buffer,
const jsmntok_t *obj UNNEEDED,
const jsmntok_t *params)
{
struct onion_hop *hops;
struct node_id *first_id;
struct pubkey *blinding;
struct sphinx_path *sphinx_path;
struct onionpacket *op;
struct secret *path_secrets;
size_t onion_size;
if (!param(cmd, buffer, params,
p_req("first_id", param_node_id, &first_id),
p_req("blinding", param_pubkey, &blinding),
p_req("hops", param_onion_hops, &hops),
NULL))
return command_param_failed();
if (!feature_offered(cmd->ld->our_features->bits[NODE_ANNOUNCE_FEATURE],
OPT_ONION_MESSAGES))
return command_fail(cmd, LIGHTNINGD,
"experimental-onion-messages not enabled");
/* Sanity check first; gossipd doesn't bother telling us if peer
* can't be reached. */
if (!peer_by_id(cmd->ld, first_id))
return command_fail(cmd, LIGHTNINGD, "Unknown first peer");
/* Create an onion which encodes this. */
sphinx_path = sphinx_path_new(cmd, NULL);
for (size_t i = 0; i < tal_count(hops); i++)
sphinx_add_modern_hop(sphinx_path, &hops[i].node, hops[i].tlv);
/* BOLT-onion-message #4:
* - SHOULD set `len` to 1366 or 32834.
*/
if (sphinx_path_payloads_size(sphinx_path) <= ROUTING_INFO_SIZE)
onion_size = ROUTING_INFO_SIZE;
else
onion_size = 32768;
op = create_onionpacket(tmpctx, sphinx_path, onion_size, &path_secrets);
if (!op)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"Creating onion failed (tlvs too long?)");
subd_send_msg(cmd->ld->gossip,
take(towire_gossipd_send_onionmsg(NULL, first_id,
serialize_onionpacket(tmpctx, op),
blinding)));
return command_success(cmd, json_stream_success(cmd));
}
static const struct json_command sendonionmessage_command = {
"sendonionmessage",
"utility",
json_sendonionmessage,
"Send message to {first_id}, using {blinding}, encoded over {hops} (id, tlv)"
};
AUTODATA(json_command, &sendonionmessage_command);
static struct command_result *param_pubkeys(struct command *cmd,
const char *name,
const char *buffer,
const jsmntok_t *tok,
struct pubkey **pubkeys)
{
size_t i;
const jsmntok_t *t;
if (tok->type != JSMN_ARRAY || tok->size == 0)
return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
"%s must be an (non-empty) array", name);
*pubkeys = tal_arr(cmd, struct pubkey, tok->size);
json_for_each_arr(i, t, tok) {
if (!json_to_pubkey(buffer, t, &(*pubkeys)[i]))
return command_fail_badparam(cmd, name, buffer, t,
"should be a compressed pubkey");
}
return NULL;
}
static struct command_result *json_blindedpath(struct command *cmd,
const char *buffer,
const jsmntok_t *obj UNNEEDED,
const jsmntok_t *params)
{
struct pubkey *ids;
struct onionmsg_path **path;
struct privkey blinding_iter;
struct pubkey first_blinding, first_node, me;
size_t nhops;
struct json_stream *response;
if (!param(cmd, buffer, params,
p_req("ids", param_pubkeys, &ids),
NULL))
return command_param_failed();
nhops = tal_count(ids);
/* Final id should be us! */
if (!pubkey_from_node_id(&me, &cmd->ld->id))
fatal("My id %s is invalid?",
type_to_string(tmpctx, struct node_id, &cmd->ld->id));
first_node = ids[0];
if (!pubkey_eq(&ids[nhops-1], &me))
return command_fail(cmd, LIGHTNINGD,
"Final of ids must be this node (%s), not %s",
type_to_string(tmpctx, struct pubkey, &me),
type_to_string(tmpctx, struct pubkey,
&ids[nhops-1]));
randombytes_buf(&blinding_iter, sizeof(blinding_iter));
if (!pubkey_from_privkey(&blinding_iter, &first_blinding))
/* Should not happen! */
return command_fail(cmd, LIGHTNINGD,
"Could not convert blinding to pubkey!");
/* We convert ids into aliases as we go. */
path = tal_arr(cmd, struct onionmsg_path *, nhops);
for (size_t i = 0; i < nhops - 1; i++) {
path[i] = tal(path, struct onionmsg_path);
path[i]->enctlv = create_enctlv(path[i],
&blinding_iter,
&ids[i],
&ids[i+1],
/* FIXME: Pad? */
0,
NULL,
&blinding_iter,
&path[i]->node_id);
}
/* FIXME: Add padding! */
path[nhops-1] = tal(path, struct onionmsg_path);
path[nhops-1]->enctlv = create_final_enctlv(path[nhops-1],
&blinding_iter,
&ids[nhops-1],
/* FIXME: Pad? */
0,
&cmd->ld->onion_reply_secret,
&path[nhops-1]->node_id);
response = json_stream_success(cmd);
json_add_blindedpath(response, "blindedpath",
&first_blinding, &first_node, path);
return command_success(cmd, response);
}
static const struct json_command blindedpath_command = {
"blindedpath",
"utility",
json_blindedpath,
"Create blinded path to us along {ids} (pubkey array ending in our id)"
};
AUTODATA(json_command, &blindedpath_command);