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Differential D5525

xdiff: don't attempt to use fuzzer inputs larger than 100k
ClosedPublic

Authored by durin42 on Jan 8 2019, 10:31 AM.

Details

Reviewers
pulkit
Group Reviewers
hg-reviewers
Commits
rHG2e60a77b7058: xdiff: don't attempt to use fuzzer inputs larger than 100k
Summary

This is the recommended approach from [0], and limiting the input was
suggested in https://github.com/google/oss-fuzz/issues/2076 when
discussing our broken coverage build.

0: https://github.com/google/oss-fuzz/blob/master/docs/new_project_guide.md#custom-libfuzzer-options-for-clusterfuzz

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

durin42 created this revision.Jan 8 2019, 10:31 AM
pulkit accepted this revision.Jan 9 2019, 3:56 AM
Closed by commit rHG2e60a77b7058: xdiff: don't attempt to use fuzzer inputs larger than 100k (authored by durin42). · Explain WhyJan 9 2019, 4:49 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mcontrib/fuzz/xdiff.cc (5 lines)

Diff 13090

contrib/fuzz/xdiff.cc

int hunk_consumer(long a1, long a2, long b1, long b2, void *priv) int hunk_consumer(long a1, long a2, long b1, long b2, void *priv)
{ {
// TODO: probably also test returning -1 from this when things break? // TODO: probably also test returning -1 from this when things break?
return 0; return 0;
} }
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{ {
// Don't allow fuzzer inputs larger than 100k, since we'll just bog
// down and not accomplish much.
if (Size > 100000) {
return 0;
}
auto maybe_inputs = SplitInputs(Data, Size); auto maybe_inputs = SplitInputs(Data, Size);
if (!maybe_inputs) { if (!maybe_inputs) {
return 0; return 0;
} }
auto inputs = std::move(maybe_inputs.value()); auto inputs = std::move(maybe_inputs.value());
mmfile_t a, b; mmfile_t a, b;
a.ptr = inputs.left.get(); a.ptr = inputs.left.get();