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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stddef.h>
#include <stdint.h>
#include <vector>
#define PNG_INTERNAL
#include "png.h"
struct BufState {
const uint8_t* data;
size_t bytes_left;
};
struct PngObjectHandler {
png_infop info_ptr = nullptr;
png_structp png_ptr = nullptr;
png_voidp row_ptr = nullptr;
BufState* buf_state = nullptr;
~PngObjectHandler() {
if (row_ptr && png_ptr) {
png_free(png_ptr, row_ptr);
}
if (png_ptr && info_ptr) {
png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
}
delete buf_state;
}
};
void user_read_data(png_structp png_ptr, png_bytep data, png_size_t length) {
BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
if (length > buf_state->bytes_left) {
png_error(png_ptr, "read error");
}
memcpy(data, buf_state->data, length);
buf_state->bytes_left -= length;
buf_state->data += length;
}
static const int kPngHeaderSize = 8;
// Entry point for LibFuzzer.
// Roughly follows the libpng book example:
// http://www.libpng.org/pub/png/book/chapter13.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
if (size < kPngHeaderSize) {
return 0;
}
std::vector<unsigned char> v(data, data + size);
if (png_sig_cmp(v.data(), 0, kPngHeaderSize)) {
// not a PNG.
return 0;
}
PngObjectHandler png_handler;
png_handler.png_ptr = png_create_read_struct
(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
if (!png_handler.png_ptr) {
return 0;
}
png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
if (!png_handler.info_ptr) {
return 0;
}
// Setting up reading from buffer.
png_handler.buf_state = new BufState();
png_handler.buf_state->data = data + kPngHeaderSize;
png_handler.buf_state->bytes_left = size - kPngHeaderSize;
png_set_read_fn(png_handler.png_ptr, png_handler.buf_state, user_read_data);
png_set_sig_bytes(png_handler.png_ptr, kPngHeaderSize);
// libpng error handling.
if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
return 0;
}
// Reading.
png_read_info(png_handler.png_ptr, png_handler.info_ptr);
png_handler.row_ptr = png_malloc(
png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
png_handler.info_ptr));
// reset error handler to put png_deleter into scope.
if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
return 0;
}
png_uint_32 width, height;
int bit_depth, color_type, interlace_type, compression_type;
int filter_type;
if (!png_get_IHDR(png_handler.png_ptr, png_handler.info_ptr, &width,
&height, &bit_depth, &color_type, &interlace_type,
&compression_type, &filter_type)) {
return 0;
}
// This is going to be too slow.
if (width && height > 100000000 / width)
return 0;
int passes = png_set_interlace_handling(png_handler.png_ptr);
png_start_read_image(png_handler.png_ptr);
for (int pass = 0; pass < passes; ++pass) {
for (png_uint_32 y = 0; y < height; ++y) {
png_read_row(png_handler.png_ptr,
static_cast<png_bytep>(png_handler.row_ptr), NULL);
}
}
return 0;
}
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