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

Table of contents

Project overview: libwebsockets
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: lws_upng_inflate_fuzzer
Call tree
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/libwebsockets/lws_upng_inflate_fuzzer.cpp
Dictionary
Fuzzer function priority
Runtime coverage analysis
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2026-05-24

Project overview: libwebsockets

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
2.0%
19 / 1199
Cyclomatic complexity statically reachable by fuzzers
2.0%
188 / 10418
Runtime code coverage of functions
0.0%
0 / 1199

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
lws_upng_inflate_fuzzer /src/libwebsockets/lws_upng_inflate_fuzzer.cpp 31 1480 7 6 517 213 lws_upng_inflate_fuzzer.cpp

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: lws_upng_inflate_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

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
rops_handle_POLLIN_h1 /src/libwebsockets/lib/roles/h1/ops-h1.c 3 ['N/A', 'N/A', 'N/A'] 35 0 300 48 21 722 0 5757 5699
lws_create_context /src/libwebsockets/lib/core/context.c 1 ['N/A'] 29 0 2014 221 79 586 0 3862 667
lws_display_render_jpeg /src/libwebsockets/lib/misc/dlo/dlo-jpeg.c 1 ['N/A'] 9 0 448 53 22 78 0 553 472
secstream_ws /src/libwebsockets/lib/secure-streams/protocols/ss-ws.c 5 ['N/A', 'int', 'N/A', 'N/A', 'size_t'] 28 0 770 113 36 413 0 2822 429
lws_cache_heap_write /src/libwebsockets/lib/misc/cache-ttl/heap.c 6 ['N/A', 'N/A', 'N/A', 'size_t', 'size_t', 'N/A'] 16 0 332 43 15 60 0 294 175
rops_perform_user_POLLOUT_h2 /src/libwebsockets/lib/roles/h2/ops-h2.c 1 ['N/A'] 33 0 939 128 51 463 0 3614 169
lws_display_render_png /src/libwebsockets/lib/misc/dlo/dlo-png.c 1 ['N/A'] 8 0 463 53 22 45 0 378 143
lws_context_default_loop_run_destroy /src/libwebsockets/lib/core/libwebsockets.c 1 ['N/A'] 31 0 46 9 4 395 0 2416 129
rops_handle_POLLIN_netlink /src/libwebsockets/lib/roles/netlink/ops-netlink.c 3 ['N/A', 'N/A', 'N/A'] 20 0 1432 160 35 332 0 2084 113
lws_x509_create_self_signed /src/libwebsockets/lib/tls/openssl/openssl-x509.c 7 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'int'] 6 0 53 6 3 54 0 179 112

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

Functions statically reachable by fuzzers
61.0%
730 / 1199
Cyclomatic complexity statically reachable by fuzzers
75.0%
7764 / 10418

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/libwebsockets/lws_upng_inflate_fuzzer.cpp

Dictionary

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


Runtime coverage analysis

No runtime coverage data was found

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/libwebsockets/lib/misc/cache-ttl/heap.c [] []
/src/libwebsockets/lib/roles/raw-file/ops-raw-file.c [] []
/src/libwebsockets/lib/system/stdin.c [] []
/src/libwebsockets/lib/core-net/client/connect3.c [] []
/src/libwebsockets/lib/core-net/service.c [] []
/src/libwebsockets/lib/core/logs.c ['lws_upng_inflate_fuzzer'] []
/src/libwebsockets/lib/core-net/route.c [] []
/src/libwebsockets/include/libwebsockets/lws-dll2.h [] []
/src/libwebsockets/lib/plat/unix/unix-init.c [] []
/src/libwebsockets/lib/roles/http/cookie.c [] []
/src/libwebsockets/lib/misc/dlo/dlo-font-mcufont.c [] []
/src/libwebsockets/lib/misc/upng.c [] []
/src/libwebsockets/lib/core-net/state.c [] []
/usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/limits [] []
/src/libwebsockets/lib/misc/dlo/dlo.c [] []
/src/libwebsockets/lib/core-net/network.c [] []
/src/libwebsockets/lib/core-net/close.c [] []
/src/libwebsockets/lib/core-net/async-ipc.c [] []
/src/libwebsockets/lib/misc/base64-decode.c [] []
/src/libwebsockets/lib/roles/netlink/ops-netlink.c [] []
/src/libwebsockets/lib/tls/openssl/openssl-ssl.c [] []
/src/libwebsockets/lib/plat/unix/unix-sockets.c [] []
/src/libwebsockets/lib/tls/openssl/openssl-client.c [] []
/src/libwebsockets/lib/secure-streams/system/fetch-policy/fetch-policy.c [] []
/src/libwebsockets/lib/tls/openssl/openssl-x509.c [] []
/src/libwebsockets/lib/misc/upng-gzip.c ['lws_upng_inflate_fuzzer'] []
/src/libwebsockets/lib/core-net/output.c [] []
/src/libwebsockets/lib/tls/openssl/openssl-tls.c [] []
/src/libwebsockets/lib/tls/openssl/openssl-server.c [] []
/src/libwebsockets/lib/core-net/wsi-timeout.c [] []
/src/libwebsockets/lib/secure-streams/protocols/ss-raw.c [] []
/src/libwebsockets/lib/event-libs/poll/poll.c [] []
/src/libwebsockets/lib/roles/raw-skt/ops-raw-skt.c [] []
/src/libwebsockets/lib/tls/lws-gencrypto-common.c [] []
/src/libwebsockets/lib/misc/cache-ttl/lws-cache-ttl.c [] []
/src/libwebsockets/lib/core/libwebsockets.c ['lws_upng_inflate_fuzzer'] []
/src/libwebsockets/lib/roles/pipe/ops-pipe.c [] []
/src/libwebsockets/lib/misc/dlo/dlo-text.c [] []
/src/libwebsockets/lib/core-net/client/connect.c [] []
/src/libwebsockets/lib/core-net/adopt.c [] []
/src/libwebsockets/lib/plat/unix/unix-caps.c [] []
/src/libwebsockets/lib/roles/h2/http2.c [] []
/src/libwebsockets/lib/secure-streams/system/captive-portal-detect/captive-portal-detect.c [] []
/src/libwebsockets/include/libwebsockets/lws-write.h [] []
/src/libwebsockets/lib/roles/http/parsers.c [] []
/src/libwebsockets/lib/roles/ws/server-ws.c [] []
/src/libwebsockets/lib/core/context.c [] []
/src/libwebsockets/lib/secure-streams/secure-streams.c [] []
/src/libwebsockets/lib/misc/lwsac/lwsac.c [] []
/src/libwebsockets/lib/misc/cache-ttl/file.c [] []
/src/libwebsockets/lib/core-net/client/connect4.c [] []
/src/libwebsockets/lib/tls/tls-client.c [] []
/src/libwebsockets/lib/plat/unix/unix-misc.c ['lws_upng_inflate_fuzzer'] []
/src/libwebsockets/lib/roles/http/client/client-http.c [] []
/src/libwebsockets/lib/secure-streams/protocols/ss-h1.c [] []
/src/libwebsockets/lib/roles/ws/client-ws.c [] []
/src/libwebsockets/lib/core-net/sorted-usec-list.c [] []
/src/libwebsockets/lib/core-net/pollfd.c [] []
/src/libwebsockets/lib/core-net/client/connect2.c [] []
/src/libwebsockets/lib/plat/unix/unix-pipe.c [] []
/src/libwebsockets/lib/tls/tls-server.c [] []
/src/libwebsockets/lib/roles/http/server/server.c [] []
/src/libwebsockets/lib/secure-streams/protocols/ss-ws.c [] []
/src/libwebsockets/lib/core-net/client/conmon.c [] []
/src/libwebsockets/lib/core/buflist.c [] []
/usr/include/openssl/x509.h [] []
/src/libwebsockets/lib/secure-streams/policy-common.c [] []
/src/libwebsockets/lib/roles/h1/ops-h1.c [] []
/src/libwebsockets/lib/tls/openssl/openssl-session.c [] []
/src/libwebsockets/lib/core/alloc.c ['lws_upng_inflate_fuzzer'] []
/src/libwebsockets/lib/roles/ws/ops-ws.c [] []
/src/libwebsockets/include/libwebsockets/lws-vfs.h [] []
/src/libwebsockets/lib/roles/h2/hpack.c [] []
/src/libwebsockets/lib/core-net/client/sort-dns.c [] []
/src/libwebsockets/lib/core-net/dummy-callback.c [] []
/src/libwebsockets/lib/system/smd/smd.c [] []
/src/libwebsockets/lib/roles/listen/ops-listen.c [] []
/src/libwebsockets/lib/tls/tls.c [] []
/src/libwebsockets/lib/roles/http/header.c [] []
/src/libwebsockets/lib/plat/unix/unix-file.c [] []
/src/libwebsockets/lib/plat/unix/unix-fds.c [] []
/src/libwebsockets/lib/secure-streams/protocols/ss-h2.c [] []
/src/libwebsockets/lib/misc/dlo/dlo-png.c [] []
/src/libwebsockets/lib/tls/tls-network.c [] []
/src/libwebsockets/lib/secure-streams/policy-json.c [] []
/src/libwebsockets/lib/core-net/wsi.c [] []
/src/libwebsockets/lib/misc/lejp.c [] []
/src/libwebsockets/lib/misc/dir-notify/dir-notify.c [] []
/src/libwebsockets/lib/core-net/vhost.c [] []
/src/libwebsockets/lws_upng_inflate_fuzzer.cpp ['lws_upng_inflate_fuzzer'] []
/src/libwebsockets/lib/system/system.c [] []
/src/libwebsockets/lib/plat/unix/unix-service.c [] []
/src/libwebsockets/lib/tls/openssl/lws-genhash.c [] []
/src/libwebsockets/lib/misc/jpeg.c [] []
/src/libwebsockets/lib/tls/tls-sessions.c [] []
/src/libwebsockets/lib/core/vfs.c [] []
/src/libwebsockets/lib/roles/ws/client-parser-ws.c [] []
/src/libwebsockets/lib/roles/http/date.c [] []
/src/libwebsockets/lib/roles/h2/ops-h2.c [] []
/src/libwebsockets/lib/misc/sha-1.c [] []
/src/libwebsockets/lib/core-net/client/client.c [] []
/src/libwebsockets/lib/misc/dlo/dlo-jpeg.c [] []
/src/libwebsockets/lib/core/lws_dll2.c [] []

Directories in report

Directory
/src/libwebsockets/lib/roles/h1/
/src/libwebsockets/lib/misc/cache-ttl/
/src/libwebsockets/lib/system/
/src/libwebsockets/lib/roles/h2/
/src/libwebsockets/lib/misc/
/usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/
/src/libwebsockets/lib/event-libs/poll/
/src/libwebsockets/lib/secure-streams/system/captive-portal-detect/
/src/libwebsockets/lib/tls/openssl/
/src/libwebsockets/lib/roles/pipe/
/src/libwebsockets/lib/plat/unix/
/src/libwebsockets/lib/roles/netlink/
/src/libwebsockets/lib/secure-streams/
/src/libwebsockets/lib/misc/dir-notify/
/src/libwebsockets/
/src/libwebsockets/lib/system/smd/
/src/libwebsockets/lib/core-net/
/src/libwebsockets/include/libwebsockets/
/src/libwebsockets/lib/roles/http/
/src/libwebsockets/lib/misc/dlo/
/src/libwebsockets/lib/roles/raw-file/
/src/libwebsockets/lib/core-net/client/
/src/libwebsockets/lib/secure-streams/system/fetch-policy/
/src/libwebsockets/lib/roles/http/client/
/src/libwebsockets/lib/roles/http/server/
/src/libwebsockets/lib/roles/raw-skt/
/src/libwebsockets/lib/secure-streams/protocols/
/src/libwebsockets/lib/tls/
/src/libwebsockets/lib/misc/lwsac/
/src/libwebsockets/lib/roles/listen/
/src/libwebsockets/lib/core/
/src/libwebsockets/lib/roles/ws/
/usr/include/openssl/

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
lws_upng_inflate_fuzzer fuzzerLogFile-0-oItj313fAx.data fuzzerLogFile-0-oItj313fAx.data.yaml