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gossip: send error messages on grossly malformed channel_announcement.

Browse source 
As per BOLT #7.  We also give more exact diagnosis.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2018-03-08 14:40:31 +10:30 • committed by Christian Decker
parent 8091e0679d
commit 5d77183c94
3 changed files with 95 additions and 31 deletions
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6
gossipd/gossip.c
View file

@ -489,8 +489,10 @@ static void handle_gossip_msg(struct peer *peer, u8 *msg)
case WIRE_CHANNEL_ANNOUNCEMENT: {
const struct short_channel_id *scid;
/* If it's OK, tells us the short_channel_id to lookup */
scid = handle_channel_announcement(rstate, msg);
if (scid)
err = handle_channel_announcement(rstate, msg, &scid);
if (err)
queue_peer_msg(peer, take(err));
else if (scid)
daemon_conn_send(&peer->daemon->master,
take(towire_gossip_get_txout(NULL,
scid)));

99
gossipd/routing.c
View file

@ -464,7 +464,7 @@ static bool check_channel_update(const struct pubkey *node_key,
return check_signed_hash(&hash, node_sig, node_key);
}
static bool check_channel_announcement(
static u8 *check_channel_announcement(const tal_t *ctx,
const struct pubkey *node1_key, const struct pubkey *node2_key,
const struct pubkey *bitcoin1_key, const struct pubkey *bitcoin2_key,
const secp256k1_ecdsa_signature *node1_sig,
@ -478,10 +478,55 @@ static bool check_channel_announcement(
sha256_double(&hash, announcement + offset,
tal_len(announcement) - offset);
return check_signed_hash(&hash, node1_sig, node1_key) &&
check_signed_hash(&hash, node2_sig, node2_key) &&
check_signed_hash(&hash, bitcoin1_sig, bitcoin1_key) &&
check_signed_hash(&hash, bitcoin2_sig, bitcoin2_key);
if (!check_signed_hash(&hash, node1_sig, node1_key)) {
return towire_errorfmt(ctx, NULL,
"Bad node_signature_1 %s hash %s"
" on node_announcement %s",
type_to_string(ctx,
secp256k1_ecdsa_signature,
node1_sig),
type_to_string(ctx,
struct sha256_double,
&hash),
tal_hex(ctx, announcement));
}
if (!check_signed_hash(&hash, node2_sig, node2_key)) {
return towire_errorfmt(ctx, NULL,
"Bad node_signature_2 %s hash %s"
" on node_announcement %s",
type_to_string(ctx,
secp256k1_ecdsa_signature,
node2_sig),
type_to_string(ctx,
struct sha256_double,
&hash),
tal_hex(ctx, announcement));
}
if (!check_signed_hash(&hash, bitcoin1_sig, bitcoin1_key)) {
return towire_errorfmt(ctx, NULL,
"Bad bitcoin_signature_1 %s hash %s"
" on node_announcement %s",
type_to_string(ctx,
secp256k1_ecdsa_signature,
bitcoin1_sig),
type_to_string(ctx,
struct sha256_double,
&hash),
tal_hex(ctx, announcement));
}
if (!check_signed_hash(&hash, bitcoin2_sig, bitcoin2_key)) {
return towire_errorfmt(ctx, NULL,
"Bad bitcoin_signature_2 %s hash %s"
" on node_announcement %s",
type_to_string(ctx,
secp256k1_ecdsa_signature,
bitcoin2_sig),
type_to_string(ctx,
struct sha256_double,
&hash),
tal_hex(ctx, announcement));
}
return NULL;
}
static void add_pending_node_announcement(struct routing_state *rstate, struct pubkey *nodeid)
@ -537,13 +582,13 @@ static void destroy_pending_cannouncement(struct pending_cannouncement *pending,
list_del_from(&rstate->pending_cannouncement, &pending->list);
}
const struct short_channel_id *handle_channel_announcement(
struct routing_state *rstate,
const u8 *announce TAKES)
u8 *handle_channel_announcement(struct routing_state *rstate,
const u8 *announce TAKES,
const struct short_channel_id **scid)
{
struct pending_cannouncement *pending;
struct bitcoin_blkid chain_hash;
u8 *features;
u8 *features, *err;
secp256k1_ecdsa_signature node_signature_1, node_signature_2;
secp256k1_ecdsa_signature bitcoin_signature_1, bitcoin_signature_2;
struct chan *chan;
@ -567,8 +612,12 @@ const struct short_channel_id *handle_channel_announcement(
&pending->node_id_2,
&pending->bitcoin_key_1,
&pending->bitcoin_key_2)) {
err = towire_errorfmt(rstate, NULL,
"Malformed channel_announcement %s",
tal_hex(pending, pending->announce));
tal_free(pending);
return NULL;
*scid = NULL;
return err;
}
/* Check if we know the channel already (no matter in what
@ -579,7 +628,9 @@ const struct short_channel_id *handle_channel_announcement(
__func__,
type_to_string(trc, struct short_channel_id,
&pending->short_channel_id));
return tal_free(pending);
tal_free(pending);
*scid = NULL;
return NULL;
}
/* We don't replace previous ones, since we might validate that and
@ -589,6 +640,7 @@ const struct short_channel_id *handle_channel_announcement(
__func__,
type_to_string(trc, struct short_channel_id,
&pending->short_channel_id));
*scid = NULL;
return tal_free(pending);
}
@ -605,6 +657,7 @@ const struct short_channel_id *handle_channel_announcement(
status_trace("Ignoring channel announcement, unsupported features %s.",
tal_hex(pending, features));
tal_free(pending);
*scid = NULL;
return NULL;
}
@ -620,23 +673,30 @@ const struct short_channel_id *handle_channel_announcement(
&pending->short_channel_id),
type_to_string(pending, struct bitcoin_blkid, &chain_hash));
tal_free(pending);
*scid = NULL;
return NULL;
}
if (!check_channel_announcement(&pending->node_id_1, &pending->node_id_2,
err = check_channel_announcement(rstate,
&pending->node_id_1,
&pending->node_id_2,
&pending->bitcoin_key_1,
&pending->bitcoin_key_2,
&node_signature_1,
&node_signature_2,
&bitcoin_signature_1,
&bitcoin_signature_2,
pending->announce)) {
status_trace("Signature verification of channel_announcement"
" for %s failed",
type_to_string(pending, struct short_channel_id,
&pending->short_channel_id));
pending->announce);
if (err) {
/* BOLT #7:
*
* - if `bitcoin_signature_1`, `bitcoin_signature_2`,
* `node_signature_1` OR `node_signature_2` are invalid OR NOT
* correct:
* - SHOULD fail the connection.
*/
tal_free(pending);
return NULL;
return err;
}
status_trace("Received channel_announcement for channel %s",
@ -651,7 +711,8 @@ const struct short_channel_id *handle_channel_announcement(
list_add_tail(&rstate->pending_cannouncement, &pending->list);
tal_add_destructor2(pending, destroy_pending_cannouncement, rstate);
return &pending->short_channel_id;
*scid = &pending->short_channel_id;
return NULL;
}
bool handle_pending_cannouncement(struct routing_state *rstate,

9
gossipd/routing.h
View file

@ -196,11 +196,12 @@ struct chan *new_chan(struct routing_state *rstate,
/**
* handle_channel_announcement -- Check channel announcement is valid
*
* Returns a short_channel_id to look up if signatures pass.
* Returns error message if we should fail channel. Make *scid non-NULL
* (for checking) if we extracted a short_channel_id, otherwise ignore.
*/
const struct short_channel_id *
handle_channel_announcement(struct routing_state *rstate,
const u8 *announce TAKES);
u8 *handle_channel_announcement(struct routing_state *rstate,
const u8 *announce TAKES,
const struct short_channel_id **scid);
/**
* handle_pending_cannouncement -- handle channel_announce once we've