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

Table of contents

Project overview: libcoap
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: pdu_parse_ws_fuzzer
Call tree
Fuzzer: split_uri_fuzzer
Call tree
Fuzzer: pdu_parse_udp_fuzzer
Call tree
Fuzzer: pdu_parse_tcp_fuzzer
Call tree
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
tests/oss-fuzz/pdu_parse_ws_target.c
Dictionary
Fuzzer function priority
tests/oss-fuzz/split_uri_target.c
Dictionary
Fuzzer function priority
tests/oss-fuzz/pdu_parse_udp_target.c
Dictionary
Fuzzer function priority
tests/oss-fuzz/pdu_parse_tcp_target.c
Dictionary
Fuzzer function priority
Runtime coverage analysis
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2025-09-05

Project overview: libcoap

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
9.0%
78 / 874
Cyclomatic complexity statically reachable by fuzzers
7.00%
588 / 7882
Runtime code coverage of functions
0.0%
0 / 874

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
pdu_parse_ws_fuzzer tests/oss-fuzz/pdu_parse_ws_target.c 97 857 7 16 1905 628 pdu_parse_ws_target.c
split_uri_fuzzer tests/oss-fuzz/split_uri_target.c 28 926 5 7 245 123 split_uri_target.c
pdu_parse_udp_fuzzer tests/oss-fuzz/pdu_parse_udp_target.c 97 857 7 16 1905 628 pdu_parse_udp_target.c
pdu_parse_tcp_fuzzer tests/oss-fuzz/pdu_parse_tcp_target.c 97 857 7 16 1905 628 pdu_parse_tcp_target.c

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: pdu_parse_ws_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.

Fuzzer: split_uri_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.

Fuzzer: pdu_parse_udp_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.

Fuzzer: pdu_parse_tcp_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
coap_ws_close /src/libcoap/src/coap_ws.c 1 ['N/A'] 56 0 389 50 17 513 2 5823 5228
coap_new_context /src/libcoap/src/coap_net.c 1 ['N/A'] 53 0 317 69 20 525 0 5797 207
coap_persist_startup /src/libcoap/src/coap_subscribe.c 5 ['N/A', 'N/A', 'N/A', 'N/A', 'int'] 59 0 57 10 3 509 0 5753 172
hnd_get_wellknown_lkd /src/libcoap/src/coap_net.c 5 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 31 0 316 50 16 496 0 5685 108
coap_new_oscore_conf /src/libcoap/src/coap_oscore.c 5 ['size_t', 'N/A', 'N/A', 'N/A', 'size_t'] 8 0 79 11 4 38 0 162 82
coap_netif_dgrm_write /src/libcoap/src/coap_netif.c 3 ['N/A', 'N/A', 'size_t'] 7 0 161 30 9 63 0 305 60
coap_io_process_loop /src/libcoap/src/coap_io.c 5 ['N/A', 'N/A', 'N/A', 'int', 'int'] 60 0 65 12 4 497 0 5628 51
coap_add_resource /src/libcoap/src/coap_resource.c 2 ['N/A', 'N/A'] 58 0 36 9 3 495 0 5643 46
coap_session_set_type_server /src/libcoap/src/coap_session.c 1 ['N/A'] 56 0 41 10 3 493 0 5621 42
coap_op_resource_deleted /src/libcoap/src/coap_subscribe.c 3 ['N/A', 'N/A', 'N/A'] 6 0 262 40 16 40 0 135 40

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

Functions statically reachable by fuzzers
61.0%
537 / 874
Cyclomatic complexity statically reachable by fuzzers
83.0%
6512 / 7882

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.

tests/oss-fuzz/pdu_parse_ws_target.c

Dictionary

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


tests/oss-fuzz/split_uri_target.c

Dictionary

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


tests/oss-fuzz/pdu_parse_udp_target.c

Dictionary

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


tests/oss-fuzz/pdu_parse_tcp_target.c

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/libcoap/src/coap_io.c [] []
/src/libcoap/src/coap_str.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/oscore/oscore_context.c [] []
/src/libcoap/src/coap_time.c ['pdu_parse_ws_fuzzer', 'split_uri_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_cache.c [] []
/src/libcoap/tests/oss-fuzz/pdu_parse_ws_target.c ['pdu_parse_ws_fuzzer'] []
/src/libcoap/src/coap_encode.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_net.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/tests/oss-fuzz/pdu_parse_tcp_target.c ['pdu_parse_tcp_fuzzer'] []
/src/libcoap/./include/coap3/coap_pdu_internal.h [] []
/src/libcoap/src/coap_threadsafe.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_async.c [] []
/src/libcoap/src/coap_notls.c ['pdu_parse_ws_fuzzer', 'split_uri_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_tcp.c ['pdu_parse_ws_fuzzer', 'split_uri_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_session.c [] []
/src/libcoap/src/coap_ws.c ['pdu_parse_ws_fuzzer', 'split_uri_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_uri.c ['pdu_parse_ws_fuzzer', 'split_uri_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/oscore/oscore_cbor.c [] []
/src/libcoap/src/coap_pdu.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/./include/coap3/coap_address.h [] []
/src/libcoap/tests/oss-fuzz/pdu_parse_udp_target.c ['pdu_parse_udp_fuzzer'] []
/src/libcoap/src/oscore/oscore.c [] []
/src/libcoap/src/coap_option.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_oscore.c [] []
/src/libcoap/src/coap_sha1.c [] []
/src/libcoap/src/oscore/oscore_crypto.c [] []
/src/libcoap/src/coap_dtls.c [] []
/src/libcoap/./include/coap3/coap_uri.h [] []
/src/libcoap/src/coap_resource.c [] []
/src/libcoap/src/coap_hashkey.c [] []
/src/libcoap/src/coap_proxy.c [] []
/src/libcoap/src/coap_debug.c ['pdu_parse_ws_fuzzer', 'split_uri_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_subscribe.c [] []
/src/libcoap/src/coap_mem.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_prng.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/coap_address.c [] []
/src/libcoap/tests/oss-fuzz/split_uri_target.c ['split_uri_fuzzer'] []
/src/libcoap/src/coap_netif.c [] []
/src/libcoap/src/coap_block.c ['pdu_parse_ws_fuzzer', 'pdu_parse_udp_fuzzer', 'pdu_parse_tcp_fuzzer'] []
/src/libcoap/src/oscore/oscore_cose.c [] []

Directories in report

Directory
/src/libcoap/src/
/src/libcoap/./include/coap3/
/src/libcoap/src/oscore/
/src/libcoap/tests/oss-fuzz/

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
pdu_parse_ws_fuzzer fuzzerLogFile-0-ak9G31v8zy.data fuzzerLogFile-0-ak9G31v8zy.data.yaml
split_uri_fuzzer fuzzerLogFile-0-rUtowPN4Co.data fuzzerLogFile-0-rUtowPN4Co.data.yaml
pdu_parse_udp_fuzzer fuzzerLogFile-0-QqgflOLlbE.data fuzzerLogFile-0-QqgflOLlbE.data.yaml
pdu_parse_tcp_fuzzer fuzzerLogFile-0-iZddY37mWf.data fuzzerLogFile-0-iZddY37mWf.data.yaml