Mercurial > public > mercurial-scm > hg
diff contrib/fuzz/bdiff.cc @ 38173:fa0ddd5e8fff
fuzz: extract some common utilities and use modern C++ idioms
Alex Gaynor suggested we should probably copy the left and right sides
of diffs to new blocks so we can detect over-reads in the diffing
code, and I agree. Once I got into that, I realized we should do
things with C++17 idioms rather than keep using malloc() and
free(). This change is the result. I tried to split it more than this
and failed.
Everything still compiles and works in the oss-fuzz container, so I
think we can count on C++17 being available!
Differential Revision: https://phab.mercurial-scm.org/D3675
| author | Augie Fackler <augie@google.com> |
|---|---|
| date | Sat, 28 Apr 2018 22:18:50 -0400 |
| parents | 2b9e2415f5b5 |
| children | dbc39f028c9f |
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--- a/contrib/fuzz/bdiff.cc Sat Apr 28 22:13:33 2018 -0400 +++ b/contrib/fuzz/bdiff.cc Sat Apr 28 22:18:50 2018 -0400 @@ -6,30 +6,25 @@ * This software may be used and distributed according to the terms of * the GNU General Public License, incorporated herein by reference. */ +#include <memory> #include <stdlib.h> +#include "fuzzutil.h" + extern "C" { #include "bdiff.h" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { - if (!Size) { + auto maybe_inputs = SplitInputs(Data, Size); + if (!maybe_inputs) { return 0; } - // figure out a random point in [0, Size] to split our input. - size_t split = Data[0] / 255.0 * Size; - - // left input to diff is data[1:split] - const uint8_t *left = Data + 1; - // which has len split-1 - size_t left_size = split - 1; - // right starts at the next byte after left ends - const uint8_t *right = left + left_size; - size_t right_size = Size - split; + auto inputs = std::move(maybe_inputs.value()); struct bdiff_line *a, *b; - int an = bdiff_splitlines((const char *)left, split - 1, &a); - int bn = bdiff_splitlines((const char *)right, right_size, &b); + int an = bdiff_splitlines(inputs.left.get(), inputs.left_size, &a); + int bn = bdiff_splitlines(inputs.right.get(), inputs.right_size, &b); struct bdiff_hunk l; bdiff_diff(a, an, b, bn, &l); free(a);