Validate channel_update signatures without holding a graph lock
#3310
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Collaborator
TheBlueMatt
commented
Sep 11, 2024
TheBlueMatt
commented
In the next commit we'll move to checking `channel_update`s in three steps - first we check if the `channel_update` is new and the latest for a channel, then we check the signature, and finally we update our local state. This allows us to avoid holding a lock on `NetworkGraph::channels` while validating the message signature. Here we do a quick prefactor to make that simpler - moving the validation logic of `channel_update` that we'll do in step one (and repeat in step three) into a local function. We also take this opportunity to do one static check unlocked which we had been doing while holding a `channel` lock.
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #3310 +/- ##
==========================================
+ Coverage 89.64% 90.97% +1.32%
==========================================
Files 126 126
Lines 102251 112645 +10394
Branches 102251 112645 +10394
==========================================
+ Hits 91666 102479 +10813
+ Misses 7863 7576 -287
+ Partials 2722 2590 -132
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. |
jkczyz
reviewed
Sep 12, 2024
| if msg.channel_flags & 1 == 1 { | ||
| if let Some(sig) = sig { | ||
| secp_verify_sig!(self.secp_ctx, &msg_hash, &sig, &PublicKey::from_slice(channel.node_two.as_slice()).map_err(|_| LightningError{ | ||
| let node_pubkey; |
There was a problem hiding this comment.
nit:
let node_pubkey = {
// ...
};There was a problem hiding this comment.
I just find that hard to read across a long block...I know we do it a lot of places, was just trying to avoid it and try something new 🤷♂️
There was a problem hiding this comment.
Yeah, YMMV. Just seemed shorter after your change.
There was a problem hiding this comment.
At least I didn't suggest a long chaining expression. 😉
There was a problem hiding this comment.
I don't think it affects legibility much, though consistency would favor @jkczyz's suggestion.
|
Looks good, feel free to squash the fixup. |
We often process many gossip messages in parallel across different peer connections, making the `NetworkGraph` mutexes fairly contention-sensitive (not to mention the potential that we want to send a payment and need to find a path to do so). Because we need to look up a node's public key to validate a signature on `channel_update` messages, we always need to take a `NetworkGraph::channels` lock before we can validate the message. For simplicity, and to avoid taking a lock twice, we'd always validated the `channel_update` signature while holding the same lock, but here we address the contention issues by doing a `channel_update` validation in three stages. First we take a read lock on `NetworkGraph::channels` and check if the `channel_update` is new, then release the lock and validate the message signature, and finally take a write lock, (re-check if the `channel_update` is new) and update the graph.
|
Squashed. |
TheBlueMatt
force-pushed
the
2024-09-unlocked-checksig
branch
from
0325c14 to
131849f
Compare
arik-so
approved these changes
Sep 23, 2024
jkczyz
approved these changes
Sep 24, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.