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

Project functions overview

The following table shows data about each function in the project. The functions included in this table correspond to all functions that exist in the executables of the fuzzers. As such, there may be functions that are from third-party libraries.

For further technical details on the meaning of columns in the below table, please see the Glossary .

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzzer details

Fuzzer: server_fuzzer

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 92 22.8%
gold [1:9] 17 4.21%
yellow [10:29] 12 2.97%
greenyellow [30:49] 1 0.24%
lawngreen 50+ 281 69.7%
All colors 403 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
21 246 httplib::Server::routing(httplib::Request&, httplib::Response&, httplib::Stream&) call site: 00246 __assert_fail
15 167 bool httplib::detail::process_multipart_ranges_data , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&)::{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, httplib::Server::write_content_with_provider(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&)::{lambda()#1} const&)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#1}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#2}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(unsigned long, unsigned long)#1}>(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, httplib::Server::write_content_with_provider(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&)::{lambda()#1}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#2}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(unsigned long, unsigned long)#1}) call site: 00167 _ZN7httplib6detail11make_uniqueINS0_15gzip_compressorEJEEENSt3__19enable_ifIXntsr3std8is_arrayIT_EE5valueENS3_10unique_ptrIS5_NS3_14default_deleteIS5_EEEEE4typeEDpOT0_
14 374 httplib::Server::process_request(httplib::Stream&, std::__1::basic_string , std::__1::allocator > const&, int, std::__1::basic_string , std::__1::allocator > const&, int, bool, bool&, std::__1::function const&) call site: 00374 __cxa_end_catch
13 136 httplib::Server::write_response_core(httplib::Stream&, bool, httplib::Request const&, httplib::Response&, bool) call site: 00136
5 83 bool httplib::detail::process_multipart_ranges_data , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#1}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#2}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long)::{lambda(unsigned long, unsigned long)#1}>(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#1}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string , std::__1::allocator > const&)#2}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string , std::__1::allocator > const&, std::__1::basic_string , std::__1::allocator > const&, unsigned long)::{lambda(unsigned long, unsigned long)#1}) call site: 00083
4 62 httplib::detail::get_range_offset_and_length(std::__1::pair , unsigned long) call site: 00062
4 369 httplib::Server::routing(httplib::Request&, httplib::Response&, httplib::Stream&) call site: 00369 __cxa_begin_catch
2 10 httplib::Server::process_request(httplib::Stream&, std::__1::basic_string , std::__1::allocator > const&, int, std::__1::basic_string , std::__1::allocator > const&, int, bool, bool&, std::__1::function const&) call site: 00010
2 395 httplib::Server::process_request(httplib::Stream&, std::__1::basic_string , std::__1::allocator > const&, int, std::__1::basic_string , std::__1::allocator > const&, int, bool, bool&, std::__1::function const&) call site: 00395 __clang_call_terminate
1 1 LLVMFuzzerTestOneInput call site: 00001
1 58 httplib::Request::get_header_value(std::__1::basic_string , std::__1::allocator > const&, char const*, unsigned long) const call site: 00058
1 122 httplib::Server::write_response_core(httplib::Stream&, bool, httplib::Request const&, httplib::Response&, bool) call site: 00122

Runtime coverage analysis

Covered functions
189
Functions that are reachable but not covered
104
Reachable functions
344
Percentage of reachable functions covered
69.77%
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/cpp-httplib/test/fuzzing/server_fuzzer.cc 4
/src/cpp-httplib/test/fuzzing/../../httplib.h 161

Analyses and suggestions

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Func name Functions filename Arg count Args Function depth hitcount instr count bb count cyclomatic complexity Reachable functions Incoming references total cyclomatic complexity Unreached complexity
httplib::Server::read_content_core(httplib::Stream&,httplib::Request&,httplib::Response&,std::__1::function ,std::__1::function ,std::__1::function )const::{lambda(charconst*,unsignedlong,unsignedlong,unsignedlong)#1}::operator()(charconst*,unsignedlong,unsignedlong,unsignedlong)const /src/cpp-httplib/test/fuzzing/../../httplib.h 5 ['N/A', 'N/A', 'size_t', 'size_t', 'size_t'] 6 0 31 3 2 76 0 333 195
LLVMFuzzerInitialize /src/cpp-httplib/test/fuzzing/server_fuzzer.cc 2 ['N/A', 'N/A'] 6 0 199 34 23 33 0 137 137
httplib::ClientImpl::create_and_connect_socket(httplib::ClientImpl::Socket&,httplib::Error&) /src/cpp-httplib/test/fuzzing/../../httplib.h 3 ['N/A', 'N/A', 'N/A'] 9 0 42 6 3 56 0 125 121
httplib::Server::process_and_close_socket(int) /src/cpp-httplib/test/fuzzing/../../httplib.h 2 ['N/A', 'int'] 15 0 105 11 8 380 0 1852 78
httplib::detail::parse_accept_header(std::__1::basic_string ,std::__1::allocator >const&,std::__1::vector ,std::__1::allocator >,std::__1::allocator ,std::__1::allocator >>>&)::{lambda(charconst*,charconst*)#1}::operator()(charconst*,charconst*)const /src/cpp-httplib/test/fuzzing/../../httplib.h 3 ['N/A', 'N/A', 'N/A'] 3 0 352 63 61 12 0 79 65
httplib::detail::write_content_chunked ,std::__1::allocator >const&,std::__1::basic_string ,std::__1::allocator >const&)::{lambda()#1},httplib::detail::compressor>(httplib::Stream&,std::__1::function const&,httplib::Server::write_content_with_provider(httplib::Stream&,httplib::Requestconst&,httplib::Response&,std::__1::basic_string ,std::__1::allocator >const&,std::__1::basic_string ,std::__1::allocator >const&)::{lambda()#1}const&,httplib::detail::compressor&,httplib::Error&)::{lambda(std::__1::unordered_multimap ,std::__1::allocator >,std::__1::basic_string ,std::__1::allocator >,httplib::detail::case_ignore::hash,std::__1::unordered_multimap::equal_to,std::__1::allocator ,std::__1::allocator >const,std::__1::basic_string ,std::__1::allocator >>>>const&)#1}::operator()(std::__1::unordered_multimap ,std::__1::allocator >,std::__1::basic_string ,std::__1::allocator >,httplib::detail::case_ignore::hash,std::__1::unordered_multimap::equal_to,std::__1::allocator ,std::__1::allocator >const,std::__1::basic_string ,std::__1::allocator >>>>const)const /src/cpp-httplib/test/fuzzing/../../httplib.h 2 ['N/A', 'N/A'] 2 0 20 3 2 10 0 69 63
httplib::detail::SocketStream::write(charconst*,unsignedlong) /src/cpp-httplib/test/fuzzing/../../httplib.h 3 ['N/A', 'N/A', 'size_t'] 8 0 37 6 3 38 0 57 41

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

Functions statically reachable by fuzzers
65.0%
257 / 397
Cyclomatic complexity statically reachable by fuzzers
80.0%
2392 / 2993

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

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/cpp-httplib/test/fuzzing/server_fuzzer.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=['httplib::Server::routing(httplib::Request&, httplib::Response&, httplib::Stream&)', 'bool httplib::detail::process_multipart_ranges_data, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&)::{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, httplib::Server::write_content_with_provider(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&)::{lambda()#1} const&)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#1}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#2}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(unsigned long, unsigned long)#1}>(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, httplib::Server::write_content_with_provider(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&)::{lambda()#1}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#2}, httplib::detail::write_multipart_ranges_data<{lambda()#1}>(httplib::Stream&, httplib::Request const&, httplib::Response&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, {lambda()#1} const)::{lambda(unsigned long, unsigned long)#1})', 'httplib::Server::process_request(httplib::Stream&, std::__1::basic_string, std::__1::allocator > const&, int, std::__1::basic_string, std::__1::allocator > const&, int, bool, bool&, std::__1::function const&)', 'httplib::Server::write_response_core(httplib::Stream&, bool, httplib::Request const&, httplib::Response&, bool)', 'bool httplib::detail::process_multipart_ranges_data, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#1}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#2}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long)::{lambda(unsigned long, unsigned long)#1}>(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#1}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long)::{lambda(std::__1::basic_string, std::__1::allocator > const&)#2}, httplib::detail::get_multipart_ranges_data_length(httplib::Request const&, std::__1::basic_string, std::__1::allocator > const&, std::__1::basic_string, std::__1::allocator > const&, unsigned long)::{lambda(unsigned long, unsigned long)#1})', 'httplib::detail::get_range_offset_and_length(std::__1::pair, unsigned long)', 'httplib::Server::routing(httplib::Request&, httplib::Response&, httplib::Stream&)', 'httplib::Server::process_request(httplib::Stream&, std::__1::basic_string, std::__1::allocator > const&, int, std::__1::basic_string, std::__1::allocator > const&, int, bool, bool&, std::__1::function const&)', 'httplib::Server::process_request(httplib::Stream&, std::__1::basic_string, std::__1::allocator > const&, int, std::__1::basic_string, std::__1::allocator > const&, int, bool, bool&, std::__1::function const&)', 'LLVMFuzzerTestOneInput']