123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186 |
- // Copyright 2014 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 "net/spdy/fuzzing/hpack_fuzz_util.h"
- #include <algorithm>
- #include <cmath>
- #include <memory>
- #include "base/rand_util.h"
- #include "base/sys_byteorder.h"
- #include "net/third_party/quiche/src/quiche/spdy/core/hpack/hpack_constants.h"
- namespace spdy {
- namespace {
- // Sampled exponential distribution parameters:
- // Number of headers in each header set.
- const size_t kHeaderCountMean = 7;
- const size_t kHeaderCountMax = 50;
- // Selected index within list of headers.
- const size_t kHeaderIndexMean = 20;
- const size_t kHeaderIndexMax = 200;
- // Approximate distribution of header name lengths.
- const size_t kNameLengthMean = 5;
- const size_t kNameLengthMax = 30;
- // Approximate distribution of header value lengths.
- const size_t kValueLengthMean = 15;
- const size_t kValueLengthMax = 75;
- } // namespace
- using base::RandBytesAsString;
- using std::map;
- HpackFuzzUtil::GeneratorContext::GeneratorContext() = default;
- HpackFuzzUtil::GeneratorContext::~GeneratorContext() = default;
- HpackFuzzUtil::Input::Input() = default;
- HpackFuzzUtil::Input::~Input() = default;
- HpackFuzzUtil::FuzzerContext::FuzzerContext() = default;
- HpackFuzzUtil::FuzzerContext::~FuzzerContext() = default;
- // static
- void HpackFuzzUtil::InitializeGeneratorContext(GeneratorContext* context) {
- // Seed the generator with common header fixtures.
- context->names.push_back(":authority");
- context->names.push_back(":path");
- context->names.push_back(":status");
- context->names.push_back("cookie");
- context->names.push_back("content-type");
- context->names.push_back("cache-control");
- context->names.push_back("date");
- context->names.push_back("user-agent");
- context->names.push_back("via");
- context->values.push_back("/");
- context->values.push_back("/index.html");
- context->values.push_back("200");
- context->values.push_back("404");
- context->values.push_back("");
- context->values.push_back("baz=bing; foo=bar; garbage");
- context->values.push_back("baz=bing; fizzle=fazzle; garbage");
- context->values.push_back("rudolph=the-red-nosed-reindeer");
- context->values.push_back("had=a;very_shiny=nose");
- context->values.push_back("and\0if\0you\0ever\1saw\0it;");
- context->values.push_back("u; would=even;say-it\xffglows");
- }
- // static
- Http2HeaderBlock HpackFuzzUtil::NextGeneratedHeaderSet(
- GeneratorContext* context) {
- Http2HeaderBlock headers;
- size_t header_count =
- 1 + SampleExponential(kHeaderCountMean, kHeaderCountMax);
- for (size_t j = 0; j != header_count; ++j) {
- size_t name_index = SampleExponential(kHeaderIndexMean, kHeaderIndexMax);
- size_t value_index = SampleExponential(kHeaderIndexMean, kHeaderIndexMax);
- std::string name, value;
- if (name_index >= context->names.size()) {
- context->names.push_back(RandBytesAsString(
- 1 + SampleExponential(kNameLengthMean, kNameLengthMax)));
- name = context->names.back();
- } else {
- name = context->names[name_index];
- }
- if (value_index >= context->values.size()) {
- context->values.push_back(RandBytesAsString(
- 1 + SampleExponential(kValueLengthMean, kValueLengthMax)));
- value = context->values.back();
- } else {
- value = context->values[value_index];
- }
- headers[name] = value;
- }
- return headers;
- }
- // static
- size_t HpackFuzzUtil::SampleExponential(size_t mean, size_t sanity_bound) {
- return std::min(static_cast<size_t>(-std::log(base::RandDouble()) * mean),
- sanity_bound);
- }
- // static
- bool HpackFuzzUtil::NextHeaderBlock(Input* input, absl::string_view* out) {
- // ClusterFuzz may truncate input files if the fuzzer ran out of allocated
- // disk space. Be tolerant of these.
- CHECK_LE(input->offset, input->input.size());
- if (input->remaining() < sizeof(uint32_t)) {
- return false;
- }
- size_t length =
- base::NetToHost32(*reinterpret_cast<const uint32_t*>(input->ptr()));
- input->offset += sizeof(uint32_t);
- if (input->remaining() < length) {
- return false;
- }
- *out = absl::string_view(input->ptr(), length);
- input->offset += length;
- return true;
- }
- // static
- std::string HpackFuzzUtil::HeaderBlockPrefix(size_t block_size) {
- uint32_t length = base::HostToNet32(static_cast<uint32_t>(block_size));
- return std::string(reinterpret_cast<char*>(&length), sizeof(uint32_t));
- }
- // static
- void HpackFuzzUtil::InitializeFuzzerContext(FuzzerContext* context) {
- context->first_stage = std::make_unique<HpackDecoderAdapter>();
- context->second_stage = std::make_unique<HpackEncoder>();
- context->third_stage = std::make_unique<HpackDecoderAdapter>();
- }
- // static
- bool HpackFuzzUtil::RunHeaderBlockThroughFuzzerStages(
- FuzzerContext* context,
- absl::string_view input_block) {
- // First stage: Decode the input header block. This may fail on invalid input.
- if (!context->first_stage->HandleControlFrameHeadersData(
- input_block.data(), input_block.size())) {
- return false;
- }
- if (!context->first_stage->HandleControlFrameHeadersComplete()) {
- return false;
- }
- // Second stage: Re-encode the decoded header block. This must succeed.
- std::string second_stage_out = context->second_stage->EncodeHeaderBlock(
- context->first_stage->decoded_block());
- // Third stage: Expect a decoding of the re-encoded block to succeed, but
- // don't require it. It's possible for the stage-two encoder to produce an
- // output which violates decoder size tolerances.
- if (!context->third_stage->HandleControlFrameHeadersData(
- second_stage_out.data(), second_stage_out.length())) {
- return false;
- }
- if (!context->third_stage->HandleControlFrameHeadersComplete()) {
- return false;
- }
- return true;
- }
- // static
- void HpackFuzzUtil::FlipBits(uint8_t* buffer,
- size_t buffer_length,
- size_t flip_per_thousand) {
- uint64_t buffer_bit_length = buffer_length * 8u;
- uint64_t bits_to_flip = flip_per_thousand * (1 + buffer_bit_length / 1024);
- // Iteratively identify & flip offsets in the buffer bit-sequence.
- for (uint64_t i = 0; i != bits_to_flip; ++i) {
- uint64_t bit_offset = base::RandUint64() % buffer_bit_length;
- buffer[bit_offset / 8u] ^= (1 << (bit_offset % 8u));
- }
- }
- } // namespace spdy
|