Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues
Project coverage
Per-fuzzer coverage

Table of contents

Project overview: lwan
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: bin/fuzz/request_fuzzer.cc
Call tree
Fuzzer: bin/fuzz/h2_huffman_fuzzer.cc
Call tree
Fuzzer: bin/fuzz/pattern_fuzzer.cc
Call tree
Fuzzer: bin/fuzz/template_fuzzer.cc
Call tree
Fuzzer: samples/forthsalon/forth.c
Call tree
Fuzzer: bin/fuzz/config_fuzzer.cc
Call tree
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
bin/fuzz/request_fuzzer.cc
Dictionary
Fuzzer function priority
bin/fuzz/h2_huffman_fuzzer.cc
Dictionary
Fuzzer function priority
bin/fuzz/pattern_fuzzer.cc
Dictionary
Fuzzer function priority
bin/fuzz/template_fuzzer.cc
Dictionary
Fuzzer function priority
samples/forthsalon/forth.c
Dictionary
Fuzzer function priority
bin/fuzz/config_fuzzer.cc
Dictionary
Fuzzer function priority
Runtime coverage analysis
Fuzz driver synthesis
New fuzzers
Files and Directories in report
Files in report
Directories in report
Function call coverage
Function in each files in report
Metadata section
Sink analyser for CWEs
Report generation date: 2025-05-12

Project overview: lwan

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
8.0%
86 / 1015
Cyclomatic complexity statically reachable by fuzzers
12.0%
415 / 3594
Runtime code coverage of functions
0.0%
0 / 1015

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
bin/fuzz/request_fuzzer.cc bin/fuzz/request_fuzzer.cc 2 1015 1 1 0 0 request_fuzzer.cc
bin/fuzz/h2_huffman_fuzzer.cc bin/fuzz/h2_huffman_fuzzer.cc 5 1014 2 2 0 3 h2_huffman_fuzzer.cc
bin/fuzz/pattern_fuzzer.cc bin/fuzz/pattern_fuzzer.cc 41 996 6 2 0 123 pattern_fuzzer.cc
bin/fuzz/template_fuzzer.cc bin/fuzz/template_fuzzer.cc 71 980 14 12 0 132 template_fuzzer.cc
samples/forthsalon/forth.c samples/forthsalon/forth.c 81 979 12 8 0 182 forth.c
bin/fuzz/config_fuzzer.cc bin/fuzz/config_fuzzer.cc 28 1003 7 4 0 27 config_fuzzer.cc

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 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: bin/fuzz/request_fuzzer.cc

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

Full calltree

Call tree overview bitmap:

The project has no code coverage. Will not display blockers as blockers depend on code coverage.

Fuzzer: bin/fuzz/h2_huffman_fuzzer.cc

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

Full calltree

Call tree overview bitmap:

The project has no code coverage. Will not display blockers as blockers depend on code coverage.

Fuzzer: bin/fuzz/pattern_fuzzer.cc

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

Full calltree

Call tree overview bitmap:

The project has no code coverage. Will not display blockers as blockers depend on code coverage.

Fuzzer: bin/fuzz/template_fuzzer.cc

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

Full calltree

Call tree overview bitmap:

The project has no code coverage. Will not display blockers as blockers depend on code coverage.

Fuzzer: samples/forthsalon/forth.c

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

Full calltree

Call tree overview bitmap:

The project has no code coverage. Will not display blockers as blockers depend on code coverage.

Fuzzer: bin/fuzz/config_fuzzer.cc

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

Full calltree

Call tree overview bitmap:

The project has no code coverage. Will not display blockers as blockers depend on code coverage.

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

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

Functions statically reachable by fuzzers
8.0%
86 / 1015
Cyclomatic complexity statically reachable by fuzzers
12.0%
415 / 3594

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 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.

bin/fuzz/request_fuzzer.cc

Dictionary

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


bin/fuzz/h2_huffman_fuzzer.cc

Dictionary

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


bin/fuzz/pattern_fuzzer.cc

Dictionary

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


bin/fuzz/template_fuzzer.cc

Dictionary

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


samples/forthsalon/forth.c

Dictionary

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


bin/fuzz/config_fuzzer.cc

Dictionary

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


Runtime coverage analysis

No runtime coverage data was found

Fuzz driver synthesis

New fuzzers

The below fuzzers are templates and suggestions for how to target the set of optimal functions above

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/lwan/src/lib/lwan-pubsub.c [] []
/src/lwan/src/bin/fuzz/config_fuzzer.cc ['bin/fuzz/config_fuzzer.cc'] []
/src/lwan/src/bin/tools/statuslookupgen.c [] []
/src/lwan/src/lib/lwan-template.c ['bin/fuzz/template_fuzzer.cc'] []
/src/lwan/src/lib/missing/linux/capability.h [] []
/src/lwan/src/samples/smolsite/qrcodegen.c [] []
/src/lwan/src/samples/clock/main.c [] []
/src/lwan/src/samples/asyncawait/main.c [] []
/src/lwan/src/bin/fuzz/pattern_fuzzer.cc ['bin/fuzz/pattern_fuzzer.cc'] []
/src/lwan/src/lib/lwan-h2-huffman.c ['bin/fuzz/h2_huffman_fuzzer.cc'] []
/src/lwan/src/lib/missing/ioprio.h [] []
/src/lwan/src/lib/lwan-socket.c [] []
/src/lwan/src/lib/realpathat.c [] []
/src/lwan/src/lib/sha1.c [] []
/src/lwan/src/lib/lwan-request.c [] []
/src/lwan/src/samples/freegeoip/freegeoip.c [] []
/src/lwan/src/lib/lwan-cache.c [] []
/src/lwan/src/lib/lwan-trie.c [] []
/src/lwan/src/lib/lwan-http-authorize.c [] []
/src/lwan/src/lib/lwan-config.c ['bin/fuzz/template_fuzzer.cc', 'bin/fuzz/config_fuzzer.cc'] []
/src/lwan/src/bin/fuzz/template_fuzzer.cc ['bin/fuzz/template_fuzzer.cc'] []
/src/lwan/src/lib/lwan-websocket.c [] []
/src/lwan/src/samples/hello-no-meta/main.c [] []
/src/lwan/src/lib/lwan-tq.c [] []
/src/lwan/src/lib/lwan-template.h ['bin/fuzz/template_fuzzer.cc'] []
/src/lwan/src/lib/missing.c ['bin/fuzz/template_fuzzer.cc', 'samples/forthsalon/forth.c'] []
/src/lwan/src/bin/lwan/main.c [] []
/src/lwan/src/samples/send-money-json-api/main.c [] []
/src/lwan/src/bin/fuzz/request_fuzzer.cc ['bin/fuzz/request_fuzzer.cc'] []
/src/lwan/src/lib/lwan-io-wrappers.c [] []
/src/lwan/src/lib/timeout.c [] []
/src/lwan/src/lib/lwan-array.h [] []
/src/lwan/src/lib/lwan-lua.c ['bin/fuzz/template_fuzzer.cc', 'samples/forthsalon/forth.c'] []
/src/lwan/src/samples/chatr/main.c [] []
/src/lwan/src/lib/int-to-str.c [] []
/src/lwan/src/samples/clock/gifenc.c [] []
/src/lwan/src/samples/clock/xdaliclock.c [] []
/src/lwan/src/lib/hash.c ['bin/fuzz/template_fuzzer.cc', 'samples/forthsalon/forth.c', 'bin/fuzz/config_fuzzer.cc'] []
/src/lwan/src/lib/lwan-status.c [] []
/src/lwan/src/samples/websocket/main.c [] []
/src/lwan/src/samples/forthsalon/forth.c ['samples/forthsalon/forth.c'] []
/src/lwan/src/lib/list.c [] []
/src/lwan/src/lib/base64.c [] []
/src/lwan/src/3rdparty/libucontext/examples/cooperative_threading.c [] []
/src/lwan/src/3rdparty/libucontext/arch/ppc64/retfromsyscall.c [] []
/src/lwan/src/samples/smolsite/main.c [] []
/src/lwan/src/samples/clock/pong.c [] []
/src/lwan/src/samples/smolsite/junzip.c [] []
/src/lwan/src/lib/lwan.h [] []
/src/lwan/src/bin/fuzz/h2_huffman_fuzzer.cc ['bin/fuzz/h2_huffman_fuzzer.cc'] []
/src/lwan/src/lib/lwan-time.c [] []
/src/lwan/src/samples/techempower/database.c ['bin/fuzz/template_fuzzer.cc', 'samples/forthsalon/forth.c'] []
/src/lwan/src/lib/lwan-arena.c [] []
/src/lwan/src/lib/lwan-straitjacket.c [] []
/src/lwan/src/lib/lwan-strbuf.c ['bin/fuzz/template_fuzzer.cc', 'bin/fuzz/config_fuzzer.cc'] []
/src/lwan/src/3rdparty/libucontext/arch/common/common-trampoline.c [] []
/src/lwan/src/bin/tools/mimegen.c [] []
/src/lwan/src/lib/missing/stdlib.h [] []
/src/lwan/src/lib/lwan-http-authorize.h [] []
/src/lwan/src/lib/missing/string.h ['samples/forthsalon/forth.c'] []
/src/lwan/src/bin/tools/configdump.c [] []
/src/lwan/src/samples/clock/blocks.c [] []
/src/lwan/src/3rdparty/libucontext/libucontext_posix.c [] []
/src/lwan/src/samples/techempower/json.c ['bin/fuzz/template_fuzzer.cc', 'samples/forthsalon/forth.c'] []
/src/lwan/src/bin/tools/weighttp.c [] []
/src/lwan/src/lib/lwan-mod-lua.c [] []
/src/lwan/src/lib/lwan-private.h [] []
/src/lwan/src/3rdparty/libucontext/arch/x86_64/makecontext.c [] []
/src/lwan/src/samples/pastebin/main.c [] []
/src/lwan/src/lib/list.h ['bin/fuzz/template_fuzzer.cc'] []
/src/lwan/src/lib/lwan-coro.c [] []
/src/lwan/src/lib/hash.h [] []
/src/lwan/src/lib/lwan-mod-redirect.c [] []
/src/lwan/src/samples/techempower/techempower.c ['bin/fuzz/template_fuzzer.cc', 'samples/forthsalon/forth.c'] []
/src/lwan/src/lib/lwan-array.c [] []
/src/lwan/src/samples/clock/numbers.c [] []
/src/lwan/src/samples/forthsalon/gif.h [] []
/src/lwan/src/lib/base64.h [] []
/src/lwan/src/lib/lwan-mod-response.c [] []
/src/lwan/src/lib/missing-pthread.c [] []
/src/lwan/src/lib/lwan-io-wrappers.h [] []
/src/lwan/src/lib/lwan-response.c [] []
/src/lwan/src/lib/lwan-tables.c [] []
/src/lwan/src/lib/lwan-thread.c [] []
/src/lwan/src/lib/missing-epoll.c [] []
/src/lwan/src/bin/tools/bin2hex.c [] []
/src/lwan/src/3rdparty/libucontext/test_libucontext_posix.c [] []
/src/lwan/src/lib/lwan.c [] []
/src/lwan/src/lib/patterns.c ['bin/fuzz/pattern_fuzzer.cc'] []
/src/lwan/src/lib/lwan-mod-fastcgi.c [] []
/src/lwan/src/lib/lwan-mod-rewrite.c [] []
/src/lwan/src/lib/sd-daemon.c [] []
/src/lwan/src/lib/lwan-strbuf.h [] []
/src/lwan/src/lib/lwan-readahead.c [] []
/src/lwan/src/lib/sd-daemon.h [] []
/src/lwan/src/lib/lwan-mod-serve-files.c [] []
/src/lwan/src/lib/lwan-job.c [] []
/src/lwan/src/samples/forthsalon/main.c [] []
/src/lwan/src/samples/techempower/json.h [] []

Directories in report

Directory
/src/lwan/src/3rdparty/libucontext/
/src/lwan/src/bin/fuzz/
/src/lwan/src/samples/chatr/
/src/lwan/src/lib/missing/linux/
/src/lwan/src/samples/techempower/
/src/lwan/src/samples/asyncawait/
/src/lwan/src/samples/websocket/
/src/lwan/src/bin/lwan/
/src/lwan/src/bin/tools/
/src/lwan/src/3rdparty/libucontext/arch/common/
/src/lwan/src/samples/forthsalon/
/src/lwan/src/3rdparty/libucontext/arch/ppc64/
/src/lwan/src/samples/smolsite/
/src/lwan/src/3rdparty/libucontext/examples/
/src/lwan/src/samples/send-money-json-api/
/src/lwan/src/samples/pastebin/
/src/lwan/src/lib/
/src/lwan/src/3rdparty/libucontext/arch/x86_64/
/src/lwan/src/samples/clock/
/src/lwan/src/samples/hello-no-meta/
/src/lwan/src/lib/missing/
/src/lwan/src/samples/freegeoip/

Function call coverage

This section shows a list of 3rd party function calls and their relative coverage information. By static analysis of the target project code, all of the 3rd party function call and their caller information, including the source file and line number that initiate the call are captured. The caller source code file and line number are shown in column 2 while column 1 is the function name of the 3rd party function call. Each occurrent of the 3rd party function call will occuply a separate row. Column 3 of each row indicate if the 3rd party call in the source file line is unreachable. Column 4 lists all fuzzers that have covered that particular system call in that specific location (source file and line)during their dynamic fuzzing.

Function in each files in report

Target sink Callsite location Reached by fuzzer Covered by Fuzzers

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file
bin/fuzz/request_fuzzer.cc fuzzerLogFile-request_fuzzer.data fuzzerLogFile-request_fuzzer.data.yaml
bin/fuzz/h2_huffman_fuzzer.cc fuzzerLogFile-h2_huffman_fuzzer.data fuzzerLogFile-h2_huffman_fuzzer.data.yaml
bin/fuzz/pattern_fuzzer.cc fuzzerLogFile-pattern_fuzzer.data fuzzerLogFile-pattern_fuzzer.data.yaml
bin/fuzz/template_fuzzer.cc fuzzerLogFile-template_fuzzer.data fuzzerLogFile-template_fuzzer.data.yaml
samples/forthsalon/forth.c fuzzerLogFile-forth.data fuzzerLogFile-forth.data.yaml
bin/fuzz/config_fuzzer.cc fuzzerLogFile-config_fuzzer.data fuzzerLogFile-config_fuzzer.data.yaml

Sink analyser for CWEs

No sink functions/methods found in the target project.