p2p/rlpx: 2KB maximum size for handshake messages #30029
Merged
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
infosecual
requested review from
fjl,
zsfelfoldi,
karalabe,
holiman and
rjl493456442
as code owners
lightclient
reviewed
Jun 19, 2024
There was a problem hiding this comment.
This make sense to me in general. The original motivation for setting the base protocol max msg size to 2 kb specifically mentions wanting to limit allocations due to untrusted nodes handshaking.
fjl
reviewed
Jun 19, 2024
core/types/rlp_fuzzer_test.go
Outdated
| @@ -104,7 +104,7 @@ func fuzzRlp(t *testing.T, input []byte) { | |||
| { | |||
| var v struct { | |||
| Byte [10]byte | |||
| Rool [10]bool | |||
fjl
changed the title
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Outdated suggestions cannot be applied.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.
This PR adds a check to reject encrypted RLPx handshakes challenge/response messages that are larger than 2KB in size.
This is consistent with the
baseProtocolMaxMsgSize(2KB) of all subsequent handshake related messages (enforced here). Since these initial encrypted handshake challenge messages are processed in a different part of the RLP handshake state handler, they are not currently enforced to a max of 2KB and can be as large as 65KB. This is due to the buffer read size being pulled from the message itself w the maximum size being what can be encoded in the 2 byte size prefix (essentiallyUINT16MAX).I believe that 2KB is more than enough size to contain any valid encrypted RLP handshake auth or response packet as these messages are typically ~400 bytes max. 2KB also allows for forward compatibility in the case that something is added to the message's extra data
Restfield while preventing any larger message size that could be abused and maintains consistency with thebaseProtocolMaxMsgSizelimits of the rest of the RLP handshake messages.