Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues

Fuzzer details

Fuzzer: fuzz_decode_streaming

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 67 11.1%
gold [1:9] 18 2.98%
yellow [10:29] 6 0.99%
greenyellow [30:49] 3 0.49%
lawngreen 50+ 509 84.4%
All colors 603 100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity Unique Reachable Complexities Unique Reachable Functions All non-covered Complexity All Reachable Complexity Function Name Function Callsite Blocked Branch
9 9 1 :

['Shift']

9 9 BrotliTransformDictionaryWord call site: 00185 /src/brunsli/_deps/brotli-src/c/common/transform.c:271
0 9 2 :

['brunsli::SkipAvailableBytes(brunsli::internal::dec::State*, unsigned long)', 'brunsli::RemainingSectionLength(brunsli::internal::dec::State*)']

0 66 brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:1864
0 2 1 :

['SaveErrorCode']

0 2 BrotliDecoderTakeOutput call site: 00206 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2563
0 0 None 9 9 BrotliTransformDictionaryWord call site: 00184 /src/brunsli/_deps/brotli-src/c/common/transform.c:267
0 0 None 4 11 brunsli::(anonymousnamespace)::EncodeCOM(brunsli::JPEGDataconst&,brunsli::internal::dec::SerializationState*) call site: 00000 /src/brunsli/c/dec/jpeg_data_writer.cc:493
0 0 None 2 488 brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:1847
0 0 None 0 1380 BrotliDecoderDecompressStream call site: 00201 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2075
0 0 None 0 1380 BrotliDecoderDecompressStream call site: 00201 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2179
0 0 None 0 1347 brunsli::internal::dec::SerializeJpeg(brunsli::internal::dec::State*,brunsli::JPEGDataconst&,unsignedlong*,unsignedchar**) call site: 00000 /src/brunsli/c/dec/jpeg_data_writer.cc:1030
0 0 None 0 1347 brunsli::internal::dec::SerializeJpeg(brunsli::internal::dec::State*,brunsli::JPEGDataconst&,unsignedlong*,unsignedchar**) call site: 00000 /src/brunsli/c/dec/jpeg_data_writer.cc:1038
0 0 None 0 1347 brunsli::internal::dec::SerializeJpeg(brunsli::internal::dec::State*,brunsli::JPEGDataconst&,unsignedlong*,unsignedchar**) call site: 00000 /src/brunsli/c/dec/jpeg_data_writer.cc:1072
0 0 None 0 182 brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:1909

Runtime coverage analysis

Covered functions
295
Functions that are reachable but not covered
69
Reachable functions
461
Percentage of reachable functions covered
85.03%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/src/brunsli/c/tests/fuzz_decode_streaming.cc 3
/src/brunsli/./c/include/brunsli/jpeg_data_writer.h 1
/src/brunsli/./c/include/brunsli/jpeg_data.h 2
/src/brunsli/c/dec/state.cc 4
/src/brunsli/c/dec/./state_internal.h 19
/src/brunsli/c/dec/./../common/lehmer_code.h 2
/src/brunsli/c/dec/./huffman_decode.h 3
/src/brunsli/c/dec/././ans_decode.h 1
/src/brunsli/c/dec/./././brunsli_input.h 1
/src/brunsli/c/dec/././arith_decode.h 1
/src/brunsli/c/dec/././serialization_state.h 4
/src/brunsli/c/dec/././output_chunk.h 5
/src/brunsli/_deps/brotli-src/c/dec/decode.c 33
/src/brunsli/_deps/brotli-src/c/dec/state.c 5
/src/brunsli/c/dec/brunsli_decode.cc 61
/src/brunsli/_deps/brotli-src/c/dec/bit_reader.c 2
/src/brunsli/_deps/brotli-src/c/common/dictionary.c 1
/src/brunsli/_deps/brotli-src/c/common/transform.c 4
/src/brunsli/_deps/brotli-src/c/dec/huffman.c 3
/src/brunsli/c/dec/bit_reader.cc 7
/src/brunsli/c/dec/../common/lehmer_code.h 4
/src/brunsli/c/dec/../common/././platform.h 1
/src/brunsli/c/common/platform.cc 1
/src/brunsli/c/include/brunsli/jpeg_data.h 1
/src/brunsli/c/common/quant_matrix.cc 1
/src/brunsli/c/dec/././huffman_decode.h 3
/src/brunsli/c/dec/huffman_decode.cc 4
/src/brunsli/c/dec/huffman_table.cc 4
/src/brunsli/c/dec/context_map_decode.cc 3
/src/brunsli/c/dec/histogram_decode.cc 2
/src/brunsli/c/dec/../common/histogram.h 1
/src/brunsli/c/dec/ans_decode.cc 1
/src/brunsli/c/dec/././brunsli_input.h 6
/src/brunsli/c/dec/../common/context.h 10
/src/brunsli/c/dec/./ans_decode.h 3
/src/brunsli/c/dec/./arith_decode.h 2
/src/brunsli/c/dec/../common/./distributions.h 2
/src/brunsli/c/common/predict.cc 2
/src/brunsli/c/common/context.cc 1
/src/brunsli/c/common/lehmer_code.cc 1
/src/brunsli/c/dec/jpeg_data_writer.cc 36
/src/brunsli/c/include/brunsli/jpeg_data_writer.h 1

Fuzzer: fuzz_decode

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 67 11.0%
gold [1:9] 16 2.64%
yellow [10:29] 10 1.65%
greenyellow [30:49] 5 0.82%
lawngreen 50+ 506 83.7%
All colors 604 100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity Unique Reachable Complexities Unique Reachable Functions All non-covered Complexity All Reachable Complexity Function Name Function Callsite Blocked Branch
9 9 1 :

['Shift']

9 9 BrotliTransformDictionaryWord call site: 00186 /src/brunsli/_deps/brotli-src/c/common/transform.c:271
0 48 11 :

['brunsli::LeaveSection(brunsli::internal::dec::SectionState*)', 'unsigned long const& std::__1::min[abi:ne180100] (unsigned long const&, unsigned long const&)', 'std::__1::vector >::empty[abi:ne180100]() const', '_ZNSt3__16vectorIhNS_9allocatorIhEEE6insertIPKhTnNS_9enable_ifIXaasr31__has_forward_iterator_categoryIT_EE5valuesr16is_constructibleIhNS_15iterator_traitsIS8_E9referenceEEE5valueEiE4typeELi0EEENS_11__wrap_iterIPhEENSE_IS6_EES8_S8_', 'std::__1::vector >::cend[abi:ne180100]() const', 'std::__1::vector >::size[abi:ne180100]() const', 'std::__1::vector >::data[abi:ne180100]()', 'brunsli::EnterSection(brunsli::internal::dec::State*, brunsli::internal::dec::SectionState*)', 'brunsli::ReadTag(brunsli::internal::dec::State*, brunsli::internal::dec::SectionState*)', 'brunsli::SkipBytes(brunsli::internal::dec::State*, unsigned long)', 'brunsli::GetBytesAvailable(brunsli::internal::dec::State*)']

0 60 brunsli::DecodeOriginalJpg(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:2025
0 9 2 :

['brunsli::SkipAvailableBytes(brunsli::internal::dec::State*, unsigned long)', 'brunsli::RemainingSectionLength(brunsli::internal::dec::State*)']

0 66 brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:1864
0 2 1 :

['SaveErrorCode']

0 2 BrotliDecoderTakeOutput call site: 00207 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2563
0 0 None 9 9 BrotliTransformDictionaryWord call site: 00185 /src/brunsli/_deps/brotli-src/c/common/transform.c:267
0 0 None 4 11 brunsli::(anonymousnamespace)::EncodeCOM(brunsli::JPEGDataconst&,brunsli::internal::dec::SerializationState*) call site: 00000 /src/brunsli/c/dec/jpeg_data_writer.cc:493
0 0 None 2 488 brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:1847
0 0 None 0 1983 brunsli::internal::dec::ProcessJpeg(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:2421
0 0 None 0 1983 brunsli::internal::dec::ProcessJpeg(brunsli::internal::dec::State*,brunsli::JPEGData*) call site: 00000 /src/brunsli/c/dec/brunsli_decode.cc:2431
0 0 None 0 1380 BrotliDecoderDecompressStream call site: 00202 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2075
0 0 None 0 1380 BrotliDecoderDecompressStream call site: 00202 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2087
0 0 None 0 1380 BrotliDecoderDecompressStream call site: 00202 /src/brunsli/_deps/brotli-src/c/dec/decode.c:2179

Runtime coverage analysis

Covered functions
312
Functions that are reachable but not covered
66
Reachable functions
463
Percentage of reachable functions covered
85.75%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/src/brunsli/c/tests/fuzz_decode.cc 3
/src/brunsli/./c/include/brunsli/jpeg_data_writer.h 1
/src/brunsli/./c/include/brunsli/jpeg_data.h 2
/src/brunsli/c/dec/brunsli_decode.cc 62
/src/brunsli/c/dec/state.cc 4
/src/brunsli/c/dec/./state_internal.h 19
/src/brunsli/c/dec/./../common/lehmer_code.h 2
/src/brunsli/c/dec/./huffman_decode.h 3
/src/brunsli/c/dec/././ans_decode.h 1
/src/brunsli/c/dec/./././brunsli_input.h 1
/src/brunsli/c/dec/././arith_decode.h 1
/src/brunsli/c/dec/././serialization_state.h 4
/src/brunsli/c/dec/././output_chunk.h 5
/src/brunsli/_deps/brotli-src/c/dec/decode.c 33
/src/brunsli/_deps/brotli-src/c/dec/state.c 5
/src/brunsli/_deps/brotli-src/c/dec/bit_reader.c 2
/src/brunsli/_deps/brotli-src/c/common/dictionary.c 1
/src/brunsli/_deps/brotli-src/c/common/transform.c 4
/src/brunsli/_deps/brotli-src/c/dec/huffman.c 3
/src/brunsli/c/dec/bit_reader.cc 7
/src/brunsli/c/dec/../common/lehmer_code.h 4
/src/brunsli/c/dec/../common/././platform.h 1
/src/brunsli/c/common/platform.cc 1
/src/brunsli/c/include/brunsli/jpeg_data.h 1
/src/brunsli/c/common/quant_matrix.cc 1
/src/brunsli/c/dec/././huffman_decode.h 3
/src/brunsli/c/dec/huffman_decode.cc 4
/src/brunsli/c/dec/huffman_table.cc 4
/src/brunsli/c/dec/context_map_decode.cc 3
/src/brunsli/c/dec/histogram_decode.cc 2
/src/brunsli/c/dec/../common/histogram.h 1
/src/brunsli/c/dec/ans_decode.cc 1
/src/brunsli/c/dec/././brunsli_input.h 6
/src/brunsli/c/dec/../common/context.h 10
/src/brunsli/c/dec/./ans_decode.h 3
/src/brunsli/c/dec/./arith_decode.h 2
/src/brunsli/c/dec/../common/./distributions.h 2
/src/brunsli/c/common/predict.cc 2
/src/brunsli/c/common/context.cc 1
/src/brunsli/c/common/lehmer_code.cc 1
/src/brunsli/c/dec/jpeg_data_writer.cc 36
/src/brunsli/c/include/brunsli/jpeg_data_writer.h 1

Fuzz engine guidance

This sections provides heuristics that can be used as input to a fuzz engine when running a given fuzz target. The current focus is on providing input that is usable by libFuzzer.

/src/brunsli/c/tests/fuzz_decode_streaming.cc

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name

-focus_function=['brunsli::internal::dec::State::State()', 'brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*, brunsli::JPEGData*)', 'bool brunsli::DecodeLimitedVarint<2ul>(brunsli::internal::dec::VarintState*, brunsli::BrunsliBitReader*, unsigned long)', 'brunsli::internal::dec::MetadataState::~MetadataState()', 'BrotliTransformDictionaryWord', 'SafeProcessCommands', 'brunsli::ProcessSection(brunsli::internal::dec::State*, brunsli::JPEGData*)', 'brunsli::(anonymous namespace)::SerializeSection(unsigned char, brunsli::internal::dec::State const&, brunsli::internal::dec::SerializationState*, brunsli::JPEGData const&)', 'brunsli::VerifySignature(brunsli::internal::dec::State*)']

/src/brunsli/c/tests/fuzz_decode.cc

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name

-focus_function=['brunsli::internal::dec::State::State()', 'brunsli::DecodeHistogramDataSection(brunsli::internal::dec::State*, brunsli::JPEGData*)', 'bool brunsli::DecodeLimitedVarint<2ul>(brunsli::internal::dec::VarintState*, brunsli::BrunsliBitReader*, unsigned long)', 'brunsli::internal::dec::MetadataState::~MetadataState()', 'BrotliTransformDictionaryWord', 'SafeProcessCommands', 'brunsli::(anonymous namespace)::SerializeSection(unsigned char, brunsli::internal::dec::State const&, brunsli::internal::dec::SerializationState*, brunsli::JPEGData const&)', 'brunsli::VerifySignature(brunsli::internal::dec::State*)', 'brunsli::DecodeHeader(brunsli::internal::dec::State*, brunsli::JPEGData*)']

Files and Directories in report

This section shows which files and directories are considered in this report. The main reason for showing this is fuzz introspector may include more code in the reasoning than is desired. This section helps identify if too many files/directories are included, e.g. third party code, which may be irrelevant for the threat model. In the event too much is included, fuzz introspector supports a configuration file that can exclude data from the report. See the following link for more information on how to create a config file: link

Files in report

Source file Reached by Covered by
[] []
/src/brunsli/c/dec/././brunsli_input.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/tests/fuzz_decode_streaming.cc ['fuzz_decode_streaming'] ['fuzz_decode_streaming']
/src/brunsli/c/tests/test_utils.cc [] []
/src/brunsli/c/dec/context_map_decode.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/./huffman_decode.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/include/brunsli/jpeg_data_writer.h ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/_deps/brotli-src/c/dec/decode.c ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/_deps/brotli-src/c/common/platform.c [] []
/src/brunsli/c/dec/././serialization_state.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/tests/./test_utils.h [] []
/src/brunsli/c/common/lehmer_code.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/./ans_decode.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/jpeg_data_writer.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/../common/context.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/ans_decode.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/././huffman_decode.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/./././brunsli_input.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/usr/local/bin/../include/c++/v1/stdexcept [] []
/src/brunsli/_deps/brotli-src/c/dec/state.c ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/./c/include/brunsli/jpeg_data.h ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/usr/local/bin/../include/c++/v1/string [] []
/src/brunsli/c/dec/../common/././platform.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/huffman_table.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/state.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/huffman_decode.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/././ans_decode.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/_deps/brotli-src/c/common/transform.c ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/common/predict.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/_deps/brotli-src/c/dec/bit_reader.c ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/common/././distributions.h [] []
/src/brunsli/c/dec/histogram_decode.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/bit_reader.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/_deps/brotli-src/c/dec/huffman.c ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/../common/histogram.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/tests/fuzz_decode.cc ['fuzz_decode'] ['fuzz_decode']
/src/brunsli/c/common/platform.cc ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/_deps/brotli-src/c/common/dictionary.c ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/./state_internal.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/../common/./distributions.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/././output_chunk.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/dec/./arith_decode.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/include/brunsli/jpeg_data.h ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/./../common/lehmer_code.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/common/context.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/../common/lehmer_code.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/./c/include/brunsli/jpeg_data_writer.h ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/brunsli_decode.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']
/src/brunsli/c/dec/././arith_decode.h ['fuzz_decode_streaming', 'fuzz_decode'] []
/src/brunsli/c/common/quant_matrix.cc ['fuzz_decode_streaming', 'fuzz_decode'] ['fuzz_decode_streaming', 'fuzz_decode']

Directories in report

Directory
/src/brunsli/c/dec/
/src/brunsli/c/dec/../common/
/usr/local/bin/../include/c++/v1/
/src/brunsli/c/include/brunsli/
/src/brunsli/c/tests/./
/src/brunsli/./c/include/brunsli/
/src/brunsli/_deps/brotli-src/c/dec/
/src/brunsli/_deps/brotli-src/c/common/
/src/brunsli/c/dec/../common/./
/src/brunsli/c/dec/./
/src/brunsli/c/tests/
/src/brunsli/c/common/
/src/brunsli/c/dec/./../common/
/src/brunsli/c/dec/./././
/src/brunsli/c/common/././
/src/brunsli/c/dec/../common/././
/src/brunsli/c/dec/././