Public commit record
58/100 · Thin
What the developer wrote
Authored by f321x
onion_message: split send_onion_message_to
Factor out code from `send_onion_message_to` into a separate
function `_create_route_to_introduction_point` to make it
easier to reason about it and more testable.
✓ Descriptive subject✓ Provides detailed explanatory context
What changed, and why it matters
This commit is a simple code cleanup: it moves a block of route-building logic into a new helper function without changing what the program actually does. There is no security fix or behavior change visible in the diff.
Recommended action
No security action needed; treat as routine refactoring.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The patch refactors send_onion_message_to in electrum/onion_message.py by extracting the route-to-introduction-point logic into create_route_to_introduction_point. The new function replicates the original code almost exactly, including the same assertions, encryption steps, and return values. A minor change is that create_onion_message_route_to now asserts that the first hop is a peer before returning a path. No functional or security-relevant changes are introduced.
Changed components
electrum/onion_message.pyInspect captured patch +80 / −59
diff --git a/electrum/onion_message.py b/electrum/onion_message.py
index e946329..f3af0ef 100644
--- a/electrum/onion_message.py
+++ b/electrum/onion_message.py
@@ -170,7 +170,11 @@ def create_onion_message_route_to(lnwallet: 'LNWallet', node_id: bytes) -> Seque
invoice_amount_msat=10000, # TODO: do this without amount constraints
node_filter=lambda x, y: True if x == lnwallet.node_keypair.pubkey else is_onion_message_node(x, y),
my_sending_channels=my_sending_channels
- ): return path
+ ):
+ # first edge must be to our peer
+ peer = lnwallet.lnpeermgr.get_peer_by_pubkey(path[0].end_node)
+ assert peer, 'first hop not a peer'
+ return path
# alt: dest is existing peer?
if lnwallet.lnpeermgr.get_peer_by_pubkey(node_id):
@@ -184,6 +188,75 @@ def create_onion_message_route_to(lnwallet: 'LNWallet', node_id: bytes) -> Seque
raise NoRouteFound('no path found')
+def create_route_to_introduction_point(
+ lnwallet: 'LNWallet',
+ blinded_path: dict,
+ introduction_point: bytes,
+ session_key: bytes
+):
+ hops_data = []
+ blinded_node_ids = []
+
+ peer = lnwallet.lnpeermgr.get_peer_by_pubkey(introduction_point)
+ # if blinded path introduction point is our direct peer, no need to route-find
+ if peer:
+ # start of blinded path is our peer
+ path_key = blinded_path['first_path_key']
+ return peer, path_key, hops_data, blinded_node_ids
+
+ path = create_onion_message_route_to(lnwallet, introduction_point)
+
+ # last edge is to introduction point and start of blinded path. remove from route
+ assert path[-1].end_node == introduction_point, 'last hop in route must be introduction point'
+
+ peer = lnwallet.lnpeermgr.get_peer_by_pubkey(path[0].end_node)
+ assert peer, "first hop is not a peer"
+
+ path = path[:-1]
+
+ if len(path) == 0:
+ # we pass the onion directly to the introduction point
+ path_key = blinded_path['first_path_key']
+ else:
+ # we construct a route to the introduction point
+ payment_path_pubkeys = [edge.end_node for edge in path]
+ hop_shared_secrets, blinded_node_ids = get_shared_secrets_along_route(
+ payment_path_pubkeys,
+ session_key)
+
+ for edge in path[:-1]:
+ hop = OnionHopsDataSingle(
+ tlv_stream_name='onionmsg_tlv',
+ blind_fields={'next_node_id': {'node_id': edge.end_node}},
+ )
+ hops_data.append(hop)
+
+ # final hop pre-ip, add next_path_key_override
+ final_hop_pre_ip = OnionHopsDataSingle(
+ tlv_stream_name='onionmsg_tlv',
+ blind_fields={
+ 'next_node_id': {'node_id': introduction_point},
+ 'next_path_key_override': {'path_key': blinded_path['first_path_key']},
+ },
+ )
+ hops_data.append(final_hop_pre_ip)
+
+ # encrypt encrypted_data_tlv here
+ for i, hop in enumerate(hops_data):
+ encrypted_recipient_data = encrypt_onionmsg_data_tlv(
+ shared_secret=hop_shared_secrets[i],
+ **hop.blind_fields)
+ payload = dict(hop.payload)
+ payload['encrypted_recipient_data'] = {
+ 'encrypted_recipient_data': encrypted_recipient_data
+ }
+ hops_data[i] = dataclasses.replace(hop, payload=payload)
+
+ path_key = ecc.ECPrivkey(session_key).get_public_key_bytes()
+
+ return peer, path_key, hops_data, blinded_node_ids
+
+
def send_onion_message_to(
lnwallet: 'LNWallet',
node_id_or_blinded_path: bytes,
@@ -213,10 +286,10 @@ def send_onion_message_to(
# https://github.com/lightning/bolts/blob/master/04-onion-routing.md
# "MUST set first_node_id to N0"
- hops_data = []
- blinded_node_ids = []
-
if lnwallet.node_keypair.pubkey == introduction_point:
+ hops_data = []
+ blinded_node_ids = []
+
# blinded path introduction point is me
our_blinding = blinded_path['first_path_key']
our_payload = blinded_path['path'][0]
@@ -248,65 +321,13 @@ def send_onion_message_to(
else:
# we need a route to introduction point
+ r = create_route_to_introduction_point(lnwallet, blinded_path, introduction_point, session_key)
+ peer, path_key, hops_data, blinded_node_ids = r
+
remaining_blinded_path = blinded_path['path']
if not isinstance(remaining_blinded_path, list): # doesn't return list when num items == 1
remaining_blinded_path = [remaining_blinded_path]
- peer = lnwallet.lnpeermgr.get_peer_by_pubkey(introduction_point)
- # if blinded path introduction point is our direct peer, no need to route-find
- if peer:
- # start of blinded path is our peer
- path_key = blinded_path['first_path_key']
- else:
- path = create_onion_message_route_to(lnwallet, introduction_point)
-
- # first edge must be to our peer
- peer = lnwallet.lnpeermgr.get_peer_by_pubkey(path[0].end_node)
- assert peer, 'first hop not a peer'
-
- # last edge is to introduction point and start of blinded path. remove from route
- assert path[-1].end_node == introduction_point, 'last hop in route must be introduction point'
-
- path = path[:-1]
-
- if len(path) == 0:
- path_key = blinded_path['first_path_key']
- else:
- payment_path_pubkeys = [edge.end_node for edge in path]
- hop_shared_secrets, blinded_node_ids = get_shared_secrets_along_route(
- payment_path_pubkeys,
- session_key)
-
- hops_data = [
- OnionHopsDataSingle(
- tlv_stream_name='onionmsg_tlv',
- blind_fields={'next_node_id': {'node_id': x.end_node}},
- ) for x in path[:-1]
- ]
-
- # final hop pre-ip, add next_path_key_override
- final_hop_pre_ip = OnionHopsDataSingle(
- tlv_stream_name='onionmsg_tlv',
- blind_fields={
- 'next_node_id': {'node_id': introduction_point},
- 'next_path_key_override': {'path_key': blinded_path['first_path_key']},
- },
- )
- hops_data.append(final_hop_pre_ip)
-
- # encrypt encrypted_data_tlv here
- for i in range(len(hops_data)):
- encrypted_recipient_data = encrypt_onionmsg_data_tlv(
- shared_secret=hop_shared_secrets[i],
- **hops_data[i].blind_fields)
- payload = dict(hops_data[i].payload)
- payload['encrypted_recipient_data'] = {
- 'encrypted_recipient_data': encrypted_recipient_data
- }
- hops_data[i] = dataclasses.replace(hops_data[i], payload=payload)
-
- path_key = ecc.ECPrivkey(session_key).get_public_key_bytes()
-
# append (remaining) blinded path and payload
blinded_path_blinded_ids = []
for i, onionmsg_hop in enumerate(remaining_blinded_path):
Risk score
Our methodology →Why this scored 15/100
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