Custom Target Patches

Certain targets require custom patches for effective fuzzing and testcase reproduction. These can be found in the target-patches directory.

Maintaining external patches should be avoided if possible, as it has several downsides:

• They might become outdated and require rebase
• They might not apply to a PR we would like to fuzz, in which case the patch needs to be adjusted just for the PR
• Testcases might not reproduce without the patches and it is on the user to make sure all patches were applied correctly

If a patch is necessary, then landing it in the target application is preferred but in the case of a fuzz blocker (e.g. checksum check in the target) the best solution is to make the harness/test produce valid inputs (if possible).

Current patches:

• bitcoin-core-rng.patch: Attempts to make Bitcoin Core's RNG deterministic
• bitcoin-core-aggressive-rng.patch: Same as bitcoin-core-rng.patch but more aggressive