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// 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.
#ifndef NET_SPDY_FUZZING_HPACK_FUZZ_UTIL_H_
#define NET_SPDY_FUZZING_HPACK_FUZZ_UTIL_H_
#include <string>
#include <vector>
#include "base/memory/scoped_ptr.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/spdy/hpack_decoder.h"
#include "net/spdy/hpack_encoder.h"
namespace net {
class NET_EXPORT_PRIVATE HpackFuzzUtil {
public:
// A GeneratorContext holds ordered header names & values which are
// initially seeded and then expanded with dynamically generated data.
struct NET_EXPORT_PRIVATE GeneratorContext {
GeneratorContext();
~GeneratorContext();
std::vector<std::string> names;
std::vector<std::string> values;
};
// Initializes a GeneratorContext with a random seed and name/value fixtures.
static void InitializeGeneratorContext(GeneratorContext* context);
// Generates a header set from the generator context.
static SpdyHeaderBlock NextGeneratedHeaderSet(GeneratorContext* context);
// Samples a size from the exponential distribution with mean |mean|,
// upper-bounded by |sanity_bound|.
static size_t SampleExponential(size_t mean, size_t sanity_bound);
// Holds an input string, and manages an offset into that string.
struct NET_EXPORT_PRIVATE Input {
Input(); // Initializes |offset| to zero.
~Input();
size_t remaining() {
return input.size() - offset;
}
const char* ptr() {
return input.data() + offset;
}
std::string input;
size_t offset;
};
// Returns true if the next header block was set at |out|. Returns
// false if no input header blocks remain.
static bool NextHeaderBlock(Input* input, base::StringPiece* out);
// Returns the serialized header block length prefix for a block of
// |block_size| bytes.
static std::string HeaderBlockPrefix(size_t block_size);
// A FuzzerContext holds fuzzer input, as well as each of the decoder and
// encoder stages which fuzzed header blocks are processed through.
struct NET_EXPORT_PRIVATE FuzzerContext {
FuzzerContext();
~FuzzerContext();
scoped_ptr<HpackDecoder> first_stage;
scoped_ptr<HpackEncoder> second_stage;
scoped_ptr<HpackDecoder> third_stage;
};
static void InitializeFuzzerContext(FuzzerContext* context);
// Runs |input_block| through |first_stage| and, iff that succeeds,
// |second_stage| and |third_stage| as well. Returns whether all stages
// processed the input without error.
static bool RunHeaderBlockThroughFuzzerStages(FuzzerContext* context,
base::StringPiece input_block);
// Flips random bits within |buffer|. The total number of flips is
// |flip_per_thousand| bits for every 1,024 bytes of |buffer_length|,
// rounding up.
static void FlipBits(uint8* buffer,
size_t buffer_length,
size_t flip_per_thousand);
};
} // namespace net
#endif // NET_SPDY_FUZZING_HPACK_FUZZ_UTIL_H_
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