From 88d12ee18e7a3df489cc600f92c4f68506d307fe Mon Sep 17 00:00:00 2001 From: bitflash-maintainer Date: Thu, 13 Aug 2026 14:50:26 +0000 Subject: consensus: cap block size at 1 MB, and stop assembling blocks we would reject CheckBlock() validated block size against MAX_SIZE, the serializer's generic 32 MB guard, not a block rule. MAX_BLOCK_SIZE did not exist in this tree at all: Bitcoin's 1 MB cap arrived in 0.3.x, after the 0.1.0 this fork came from. A miner could produce a 32 MB block and every node would download, verify and store it. Upstream #111 (from #110 by mtg0001). The cap is a tightening, so a node that does not upgrade is the permissive one. Measured upstream over 5709 blocks: largest 34,290 bytes, median 216, so 1 MB rejects nothing that exists. Upstream shipped the validation half only. Both places that ASSEMBLE a block still filled to MAX_SIZE/2 (16 MB), which was consistent against a 32 MB validation cap and is inverted by a 1 MB one -- the node would solve a block and then reject it itself. Fixed both: main.cpp CreateNewBlock, the node's own miner rpc.cpp RebuildJob, the POOL's job builder -- the one that matters here, because every miner on the pool would be working a template the network rejects, and this pool is ~90% of hashrate Half the cap in both, preserving the original margin: each test runs against a transaction that is already counted, so the loop can overshoot by one. (cherry picked from commit a3be9f04903447fa2741aff4eb529fe45f916877) --- src/rpc.cpp | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'src/rpc.cpp') diff --git a/src/rpc.cpp b/src/rpc.cpp index da22b1d..03d1f44 100644 --- a/src/rpc.cpp +++ b/src/rpc.cpp @@ -253,7 +253,13 @@ static bool RebuildJob() pool = tmp; block.vtx.push_back(tx); sz += ::GetSerializeSize(tx, SER_NETWORK); - if (sz > MAX_SIZE / 2) break; + // Must stay under the consensus cap CheckBlock() enforces. + // This is the pool's job builder, so a block over the cap + // is not just one wasted solve -- it is every miner on the + // pool working a template the network will reject. The + // transaction is already pushed above, so this can overshoot + // by one; half the cap leaves room for that. + if (sz > MAX_BLOCK_SIZE / 2) break; } } } -- cgit v1.2.3