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[libpng16] Defeat optimization that removes reading rows in the fuzzer.

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Glenn Randers-Pehrson 2017-09-23 10:34:40 -05:00
parent 90dd185aed
commit 96333b6bea
1 changed files with 9 additions and 1 deletions
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10
contrib/oss-fuzz/libpng_read_fuzzer.cc
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@ -5,7 +5,7 @@
// Use of this source code is governed by a BSD-style license that may // Use of this source code is governed by a BSD-style license that may
// be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE // be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
// Last changed in libpng 1.6.33beta03 [September 20, 2017] // Last changed in libpng 1.6.33beta03 [September 23, 2017]
// The modifications in 2017 by Glenn Randers-Pehrson include // The modifications in 2017 by Glenn Randers-Pehrson include
// 1. addition of a PNG_CLEANUP macro, // 1. addition of a PNG_CLEANUP macro,
@ -169,13 +169,21 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
int passes = png_set_interlace_handling(png_handler.png_ptr); int passes = png_set_interlace_handling(png_handler.png_ptr);
png_start_read_image(png_handler.png_ptr); png_start_read_image(png_handler.png_ptr);
int max_filter = 0;
for (int pass = 0; pass < passes; ++pass) { for (int pass = 0; pass < passes; ++pass) {
for (png_uint_32 y = 0; y < height; ++y) { for (png_uint_32 y = 0; y < height; ++y) {
png_read_row(png_handler.png_ptr, png_read_row(png_handler.png_ptr,
static_cast<png_bytep>(png_handler.row_ptr), nullptr); static_cast<png_bytep>(png_handler.row_ptr), nullptr);
max_filter = png_handler.row_buf[0] > max_filter ?
png_handler.row_buf[0] : max_filter;
} }
} }
if (max_filter > 5) {
PNG_CLEANUP
return 0;
}
png_read_end(png_handler.png_ptr, png_handler.end_info_ptr); png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
PNG_CLEANUP PNG_CLEANUP