fuzz-tests: improve fuzz-bigsize#8301
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rustyrussell merged 3 commits intoElementsProject:masterfrom Sep 15, 2025
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morehouse
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May 21, 2025
tests/fuzz/fuzz-bigsize.c
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| for (size_t i = 0; i < tal_count(wire_chunks); i++) { | ||
| wire_max = tal_count(wire_chunks[i]); | ||
| wire_ptr = wire_chunks[i]; | ||
| for (size_t max = 0; max <= BIGSIZE_MAX_LEN; max++) { |
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max is unused, so what is the purpose of looping BIGSIZE_MAX_LEN times?
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My bad, it should've been:
wire_chunks = get_chunks(NULL, data, size, max);
instead of:
wire_chunks = get_chunks(NULL, data, size, 8);
Changelog-None: The exisiting fuzz test only extracts chunks of a fixed size (8) from the fuzzer's input. Replace this with an iteration over a set of chunk sizes (1 to BIGSIZE_MAX_LEN) for better coverage. While at it, get rid of the check `if (bs != 0)` because 0 is a valid value for bigsize_t as well.
morehouse
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Jun 7, 2025
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While I'd prefer to simplify by removing the chunking entirely and setting an input max len of 8, that would completely change the existing corpus. Could still be done in the future.
tests/fuzz/fuzz-bigsize.c
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| for (size_t max = 1; max <= BIGSIZE_MAX_LEN; max++) { | ||
| wire_chunks = get_chunks(NULL, data, size, max); |
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Nit: chunk_size would be a more descriptive name
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| for (size_t max = 1; max <= BIGSIZE_MAX_LEN; max++) { | |
| wire_chunks = get_chunks(NULL, data, size, max); | |
| for (size_t chunk_size = 1; chunk_size <= BIGSIZE_MAX_LEN; chunk_size++) { | |
| wire_chunks = get_chunks(NULL, data, size, chunk_size); |
added 2 commits
June 9, 2025 06:01
Add a roundtrip check for `bigsize_put()` using `bigsize_get()`. This enforces a stricter check for the former and adds a test for the latter, which is currently untested.
Improvements in the fuzz-testing scheme of fuzz-bigsize led to the discovery of test inputs that result in greater in code-coverage. Add these inputs to the test's seed corpus.
morehouse
approved these changes
Jun 9, 2025
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Add a couple of improvements to the fuzz test for
bigsize_toperations-tests/fuzz/fuzz-bigsize. Commit the newly discovered seed corpus inputs as well.Checklist
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CC: @morehouse