fuzz-tests: Improve the fuzz-base32-64 test #8183
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morehouse
suggested changes
Apr 11, 2025
common/base64.c
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| { | ||
| size_t dlen = base64_decoded_length(len); | ||
| u8 *ret = tal_arr(ctx, u8, dlen); | ||
| if (!base64_decode((char *)ret, dlen, str, len)) |
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base64_decode returns -1 on error, not 0.
We should be verifying that the returned value matches dlen.
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We should be verifying that the returned value matches dlen.
This is not ideal because base64_decoded_length() does not return the actual size of the decoded data; it only provides the minimum buffer size required for a safe decode. This becomes evident when modifying the code as follows:
if (base64_decode((char *)ret, dlen, str, len) != dlen)
still fails the test for the input corpus. Therefore, I have updated it to:
if (base64_decode((char *)ret, dlen, str, len) < 0)
added 2 commits
April 12, 2025 05:35
Changelog-Added: Currently, fuzz testing for b64_encode() merely encodes input and frees the result, providing no real verification of its behavior. Introduce a new b64_decode() function (modeled after b32_decode()) and update the fuzz test to perform a roundtrip—encoding followed by decoding—to ensure that b64_encode() correctly preserves the original data.
Change in the fuzz-testing scheme of fuzz-base32-64 led to the discovery of test inputs that result in greater in code-coverage. Add these inputs to the test's seed corpus.
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Currently, fuzz testing for
b64_encode()in thefuzz/fuzz-base32-64test merelyencodes input and frees the result, providing no real verification of its behavior.
Introduce a new
b64_decode()function and update the fuzz test to perform aroundtrip—encoding followed by decoding—to ensure that
b64_encode()correctly preserves the original data.
Add the newly discovered inputs that result in greater code-coverage to the
seed corpus for this test.