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

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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 10 12.5%
gold [1:9] 1 1.25%
yellow [10:29] 1 1.25%
greenyellow [30:49] 7 8.75%
lawngreen 50+ 61 76.2%
All colors 80 100

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
0 0 None 6 6 _realloc call site: 00000 /src/libwebsockets/lib/core/alloc.c:140
0 0 None 4 173 lws_api_test_gunzip(FuzzedDataProvider&) call site: 00000 /src/libwebsockets/lws_upng_inflate_fuzzer.cpp:28
0 0 None 2 17 __lws_logv call site: 00005 /src/libwebsockets/lib/core/logs.c:384
0 0 None 2 2 _realloc call site: 00000 /src/libwebsockets/lib/core/alloc.c:154
0 0 None 0 501 _lws_upng_inflate_data call site: 00033 /src/libwebsockets/lib/misc/upng-gzip.c:438
0 0 None 0 501 _lws_upng_inflate_data call site: 00064 /src/libwebsockets/lib/misc/upng-gzip.c:764
0 0 None 0 501 _lws_upng_inflate_data call site: 00065 /src/libwebsockets/lib/misc/upng-gzip.c:768
0 0 None 0 501 _lws_upng_inflate_data call site: 00065 /src/libwebsockets/lib/misc/upng-gzip.c:788
0 0 None 0 41 lws_upng_inflator_create call site: 00003 /src/libwebsockets/lib/misc/upng-gzip.c:974
0 0 None 0 37 _lws_upng_inflate_data call site: 00062 /src/libwebsockets/lib/misc/upng-gzip.c:733
0 0 None 0 0 lws_snprintf call site: 00011 /src/libwebsockets/lib/core/libwebsockets.c:870
0 0 None 0 0 lws_snprintf call site: 00012 /src/libwebsockets/lib/core/libwebsockets.c:877

Runtime coverage analysis

Covered functions
21
Functions that are reachable but not covered
9
Reachable functions
28
Percentage of reachable functions covered
67.86%
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/libwebsockets/lws_upng_inflate_fuzzer.cpp 2
/src/libwebsockets/lib/misc/upng-gzip.c 10
/src/libwebsockets/lib/core/alloc.c 2
/src/libwebsockets/lib/core/logs.c 3
/src/libwebsockets/lib/core/libwebsockets.c 2

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 ['struct.lws_context_per_thread *', 'struct.lws *', 'struct.pollfd *'] 28 0 309 48 21 657 0 5037 4993
lws_create_context /src/libwebsockets/lib/core/context.c 1 ['struct.lws_context_creation_info *'] 20 0 1932 211 75 572 0 3573 805
lws_display_dlo_jpeg_new /src/libwebsockets/lib/misc/dlo/dlo-jpeg.c 3 ['struct.lws_displaylist *', 'struct.lws_dlo.1238 *', 'struct.lws_box *'] 18 0 95 12 5 338 0 2065 430
secstream_h2 /src/libwebsockets/lib/secure-streams/protocols/ss-h2.c 5 ['struct.lws.5553 *', 'int ', 'char *', 'char *', 'size_t '] 28 0 220 34 11 446 0 2856 342
rops_perform_user_POLLOUT_h2 /src/libwebsockets/lib/roles/h2/ops-h2.c 1 ['struct.lws.2857 *'] 27 0 874 121 48 428 0 3230 167
lws_cache_heap_write /src/libwebsockets/lib/misc/cache-ttl/heap.c 6 ['struct.lws_cache_ttl_lru.597 *', 'char *', 'char *', 'size_t ', 'size_t ', 'char **'] 6 0 343 39 14 59 0 275 166
lws_display_dlo_png_new /src/libwebsockets/lib/misc/dlo/dlo-png.c 3 ['struct.lws_displaylist *', 'struct.lws_dlo.1105 *', 'struct.lws_box *'] 18 0 86 10 4 310 0 1948 150
lws_context_default_loop_run_destroy /src/libwebsockets/lib/core/libwebsockets.c 1 ['struct.lws_context *'] 17 0 47 9 4 366 0 2097 112
rops_handle_POLLIN_netlink /src/libwebsockets/lib/roles/netlink/ops-netlink.c 3 ['struct.lws_context_per_thread *', 'struct.lws *', 'struct.pollfd *'] 27 0 1206 125 27 303 0 1787 100
lws_create_adopt_udp /src/libwebsockets/lib/core-net/adopt.c 10 ['struct.lws_vhost *', 'char *', 'int ', 'int ', 'char *', 'char *', 'struct.lws *', 'char *', 'struct.lws_retry_bo *', 'char *'] 31 0 228 16 6 494 0 2962 93

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

Functions statically reachable by fuzzers
66.2%
720/1087
Cyclomatic complexity statically reachable by fuzzers
79.1%
7112 / 8984

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

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

Directories in report

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