mirror of
https://github.com/bitcoin/bitcoin.git
synced 2026-03-21 21:20:07 +01:00
116b8c5573
a6ca8f3243fuzz: Fix difficulty target generation in p2p_headers_presync (marcofleon)fa327c77e3util: Add ConsumeArithUInt256InRange fuzzing helper (marcofleon) Pull request description: In the `p2p_headers_presync` fuzz target, this assertion failed: ``` assert(total_work < chainman.MinimumChainWork()); ``` Input that triggered the failure: [p2ppresync_crash.txt](https://github.com/user-attachments/files/17620203/p2ppresync_crash.txt) The test previously used `ConsumeIntegralInRange` to generate header difficulty targets within a hardcoded range. The fuzzer found specific values in that range that correspond to very low thresholds due to how [`SetCompact`][setcompact-link] works. The total work of a long enough test chain ended up exceeding `MinimumChainWork`. Fix this by adding a new `ConsumeArithUInt256InRange` helper function and use it in the fuzz test to generate target values within the originally intended range. The target is then converted to an `nBits` value using `GetCompact()`. For some more context, see https://github.com/bitcoin/bitcoin/pull/30918. [setcompact-link]:6463117a29/src/arith_uint256.h (L251-L271)ACKs for top commit: instagibbs: ACKa6ca8f3243dergoegge: Code review ACKa6ca8f3243brunoerg: code review ACKa6ca8f3243Tree-SHA512: 92013d9d37bd3f11992ee678ba9745196efbdc4d773fd14994116629260bea46ffc9fa3923d443af7b623d39c6211900ce98a349c62ad1976e12312c37ef9df0