p2p: Add `HeadersMessage` sanity check methods
What the developer wrote
Authored by rustaceanrob
p2p: Add `HeadersMessage` sanity check methods
While this collection of crates does not try to implement the bitcoin
consensus logic, it can help prevent obvious spam or noise. Any list of
block headers must be connected in a linked list by their hashes, and
each header must pass its own work requirement, regardless of network.
Adding this here because I imagine anyone that uses these types would
want to know if they are receiving garbage.
What changed, and why it matters
This commit adds two optional helper methods to check whether a list of Bitcoin block headers is correctly chained and whether each header meets its own proof-of-work target. It is a defensive, non-breaking feature addition for users of the library; it does not fix an existing vulnerability or change any default behavior.
No immediate action required. Users of `rust-bitcoin` p2p who process `HeadersMessage` may consider calling the new `is_connected()` and `all_targets_satisfied()` methods after receipt to reject obviously invalid header sequences.
Security signals we found
Defensive sanity-check helpers added for P2P `HeadersMessage`
Proof-of-work target validation exposed as an explicit method
Header chain linkage check exposed as an explicit method
No automatic enforcement on decode; callers must opt in
Evidence from the diff
The patch introduces HeadersMessage::is_connected() and HeadersMessage::all_targets_satisfied() in p2p/src/message.rs. is_connected() verifies that each header’s block_hash() equals the next header’s prev_blockhash. all_targets_satisfied() calls HeaderExt::validate_pow(header.target()) for every header. A unit test with three real mainnet headers (heights 900000-900002) is added. No existing code paths are modified, and the methods are not invoked automatically during decoding.
Changed components
p2p/src/message.rsHeadersMessage structInspect captured patch +38 / −1
diff --git a/p2p/src/message.rs b/p2p/src/message.rs
index b5506ae9..b28cf903 100644
--- a/p2p/src/message.rs
+++ b/p2p/src/message.rs
@@ -14,7 +14,7 @@ use core::{cmp, fmt};
use bitcoin::consensus::encode::{self, Decodable, Encodable, ReadExt, WriteExt};
use bitcoin::merkle_tree::MerkleBlock;
-use bitcoin::{block, transaction};
+use bitcoin::{block, block::HeaderExt, transaction};
use hashes::sha256d;
use internals::ToU64 as _;
use io::{self, BufRead, Read, Write};
@@ -527,6 +527,27 @@ impl Encodable for V2NetworkMessage {
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct HeadersMessage(pub Vec<block::Header>);
+impl HeadersMessage {
+ /// Does each header point to the previous block hash in the list.
+ pub fn is_connected(&self) -> bool {
+ self.0
+ .iter()
+ .zip(self.0.iter().skip(1))
+ .all(|(first, second)| first.block_hash().eq(&second.prev_blockhash))
+ }
+
+ /// Each header passes its own proof-of-work target.
+ pub fn all_targets_satisfied(&self) -> bool {
+ !self.0
+ .iter()
+ .any(|header| {
+ let target = header.target();
+ let valid_pow = header.validate_pow(target);
+ valid_pow.is_err()
+ })
+ }
+}
+
impl Decodable for HeadersMessage {
#[inline]
fn consensus_decode_from_finite_reader<R: BufRead + ?Sized>(
@@ -1289,4 +1310,20 @@ mod test {
deserialize(&[5u8, 0, 0, 0, 162, 107, 175, 90, 1, 2, 3, 4, 5]);
assert_eq!(cd.ok(), Some(CheckedData::new(vec![1u8, 2, 3, 4, 5])));
}
+
+ #[test]
+ fn headers_message() {
+ let block_900_000 = deserialize::<block::Header>(
+ &hex!("00a0ab20247d4d9f582f9750344cdf62c46d81d046be960340960100000000000000000070f96945530651135839d8adc3f40e595118ec74c7ad81a3d17bb022e554fb0c937f4268743702177ad05f92")
+ ).unwrap();
+ let block_900_001 = deserialize::<block::Header>(
+ &hex!("00e000208a96960d6d1ca4ee4a283fd83da309b8d5d2bfed380501000000000000000000371c9ffd63d75fb36c57d58eb842d23c0e7ec049daf16d94cc38805c346e9d52e880426874370217973dc83b")
+ ).unwrap();
+ let block_900_002 = deserialize::<block::Header>(
+ &hex!("0400ff3ffc834fac4e1eb2ae41f1f9776e0f8e24a6090603ffa8010000000000000000002efba7e7280aa60f0a650f29e30332d52e11af57bc58cc6e71f343851f016c676182426874370217e3615653")
+ ).unwrap();
+ let headers_message = HeadersMessage(vec![block_900_000, block_900_001, block_900_002]);
+ assert!(headers_message.is_connected());
+ assert!(headers_message.all_targets_satisfied());
+ }
}
Why this scored 18/100
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