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

Table of contents

Project overview: gpsd
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: FuzzPacket
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Fuzzer: FuzzJson
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/gpsd/fuzzer/FuzzPacket.c
Dictionary
Fuzzer function priority
/src/gpsd/fuzzer/FuzzJson.c
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2025-10-10

Project overview: gpsd

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
8.0%
64 / 781
Cyclomatic complexity statically reachable by fuzzers
16.0%
1283 / 7906
Runtime code coverage of functions
7.00%
56 / 781

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
FuzzPacket /src/gpsd/fuzzer/FuzzPacket.c 57 831 8 9 1809 735 FuzzPacket.c
FuzzJson /src/gpsd/fuzzer/FuzzJson.c 52 43 9 11 1470 643 FuzzJson.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: FuzzPacket

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 distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 81 24.0%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 256 75.9%
All colors 337 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
42 278 packet_get call site: 00278 packet_get1_chunked
17 9 isgps_decode call site: 00009 gpsd_vlog
3 322 packet_get1 call site: 00322 gpsd_log
2 42 nextstate call site: 00042 gpsd_log
2 95 nextstate call site: 00095 rtcm2_decode
2 119 nextstate call site: 00119 gps_hexdump
2 173 nextstate call site: 00173 gpsd_log
2 246 packet_parse call site: 00246 gpsd_log
2 331 packet_get1 call site: 00331 packet_discard
1 1 LLVMFuzzerTestOneInput call site: 00001 clock_gettime
1 32 isgps_decode call site: 00032 gpsd_log
1 186 nextstate call site: 00186 character_pushback

Runtime coverage analysis

Covered functions
28
Functions that are reachable but not covered
29
Reachable functions
57
Percentage of reachable functions covered
49.12%
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/gpsd/fuzzer/FuzzPacket.c 1
gpsd/packet.c 17
gpsd/isgps.c 3
drivers/driver_rtcm2.c 3
gpsd/libgpsd_core.c 4
libgps/hex.c 2
gpsd/../include/strfuncs.h 1
drivers/driver_greis_checksum.c 2
gpsd/crc24q.c 2

Fuzzer: FuzzJson

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 distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 19 5.91%
gold [1:9] 97 30.2%
yellow [10:29] 28 8.72%
greenyellow [30:49] 10 3.11%
lawngreen 50+ 167 52.0%
All colors 321 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
13 83 json_internal_read_object call site: 00083 iso8601_to_timespec
2 9 json_read_object call site: 00009 json_internal_read_object
2 31 json_read_array call site: 00031 json_trace
1 61 json_internal_read_object call site: 00061 atol
1 64 json_internal_read_object call site: 00064 atoi

Runtime coverage analysis

Covered functions
31
Functions that are reachable but not covered
21
Reachable functions
52
Percentage of reachable functions covered
59.62%
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/gpsd/fuzzer/FuzzJson.c 1
libgps/libgps_json.c 13
libgps/../include/strfuncs.h 1
libgps/json.c 5
libgps/gpsutils.c 3
libgps/os_compat.c 1
libgps/shared_json.c 2
libgps/rtcm2_json.c 1
libgps/rtcm3_json.c 1
libgps/ais_json.c 2
libgps/hex.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
gpsd_multipoll /src/gpsd/gpsd-3.26.2~dev/gpsd/libgpsd_core.c 4 ['bool', 'N/A', 'N/A', 'float'] 10 0 424 86 36 183 0 1915 1115
ubx_parse /src/gpsd/gpsd-3.26.2~dev/drivers/driver_ubx.c 3 ['N/A', 'N/A', 'size_t'] 7 0 2094 394 117 116 0 1107 975
tsip_parse_input /src/gpsd/gpsd-3.26.2~dev/drivers/driver_tsip.c 1 ['N/A'] 8 0 735 160 51 101 0 653 519
sirfbin_parse_input /src/gpsd/gpsd-3.26.2~dev/drivers/driver_sirf.c 1 ['N/A'] 9 0 38 8 4 87 0 804 412
aivdm_analyze /src/gpsd/gpsd-3.26.2~dev/drivers/drivers.c 1 ['N/A'] 6 0 48 10 5 45 0 421 236
skybin_parse_input /src/gpsd/gpsd-3.26.2~dev/drivers/driver_skytraq.c 1 ['N/A'] 7 0 299 60 5 75 0 465 214
rtcm104v3_analyze /src/gpsd/gpsd-3.26.2~dev/drivers/drivers.c 1 ['N/A'] 6 0 43 6 3 22 0 252 194
gps_mainloop /src/gpsd/gpsd-3.26.2~dev/libgps/libgps_core.c 3 ['N/A', 'int', 'N/A'] 11 0 120 29 12 73 0 807 138
processRMC /src/gpsd/gpsd-3.26.2~dev/drivers/driver_nmea0183.c 3 ['int', 'N/A', 'N/A'] 6 0 361 70 25 32 0 192 105
navcom_parse_input /src/gpsd/gpsd-3.26.2~dev/drivers/driver_navcom.c 1 ['N/A'] 7 0 38 8 4 48 0 291 103

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

Functions statically reachable by fuzzers
52.0%
405 / 781
Cyclomatic complexity statically reachable by fuzzers
66.0%
5188 / 7906

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/gpsd/fuzzer/FuzzPacket.c

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=['packet_get', 'isgps_decode', 'packet_get1', 'nextstate', 'packet_parse', 'LLVMFuzzerTestOneInput']

/src/gpsd/fuzzer/FuzzJson.c

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=['json_internal_read_object', 'json_read_object', 'json_read_array']

Runtime coverage analysis

This section shows analysis of runtime coverage data.

For futher technical details on how this section is generated, please see the Glossary .

Complex functions with low coverage

Func name Function total lines Lines covered at runtime percentage covered Reached by fuzzers
json_read_array 206 93 45.14% ['FuzzJson']

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/gpsd/gpsd-3.26.2~dev/drivers/driver_italk.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_tsip.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_nmea0183.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/libgps_core.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_garmin_txt.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_evermore.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/geoid.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/../include/strfuncs.h ['FuzzJson'] []
/src/gpsd/gpsd-3.26.2~dev/libgps/hex.c ['FuzzPacket', 'FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/libgps/netlib.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/timespec_str.c [] []
/src/gpsd/fuzzer/FuzzJson.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/libgps/rtcm2_json.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/libgps/../include/timespec.h [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_greis_checksum.c ['FuzzPacket'] ['FuzzPacket']
/src/gpsd/gpsd-3.26.2~dev/libgps/bits.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/rtcm3_json.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/gpsd/pseudonmea.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/os_compat.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/libgps/ais_json.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/gpsd/libgpsd_core.c ['FuzzPacket'] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/matrix.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/packet.c ['FuzzPacket'] ['FuzzPacket']
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_skytraq.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/serial.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_greis.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/gpsutils.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_casic.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_garmin.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/shared_json.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/gpsd/isgps.c ['FuzzPacket'] ['FuzzPacket']
/src/gpsd/gpsd-3.26.2~dev/gpsd/pseudoais.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/drivers.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_ubx.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_navcom.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_superstar2.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/libgps_sock.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/../include/strfuncs.h ['FuzzPacket'] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_zodiac.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_nmea2000.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/gps_maskdump.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/ppsthread.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_sirf.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/net_gnss_dispatch.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/timebase.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/subframe.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_oncore.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/crc24q.c ['FuzzPacket'] ['FuzzPacket']
/src/gpsd/gpsd-3.26.2~dev/libgps/../include/compiler.h [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/net_dgpsip.c [] []
/src/gpsd/gpsd-3.26.2~dev/libgps/json.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/libgps/libgps_json.c ['FuzzJson'] ['FuzzJson']
/src/gpsd/gpsd-3.26.2~dev/libgps/libgps_shm.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/bsd_base64.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_geostar.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_rtcm2.c ['FuzzPacket'] ['FuzzPacket']
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_allystar.c [] []
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_rtcm3.c [] []
/src/gpsd/fuzzer/FuzzPacket.c ['FuzzPacket'] ['FuzzPacket']
/src/gpsd/gpsd-3.26.2~dev/drivers/driver_ais.c [] []
/src/gpsd/gpsd-3.26.2~dev/gpsd/net_ntrip.c [] []

Directories in report

Directory
/src/gpsd/gpsd-3.26.2~dev/gpsd/../include/
/src/gpsd/gpsd-3.26.2~dev/gpsd/
/src/gpsd/gpsd-3.26.2~dev/drivers/
/src/gpsd/gpsd-3.26.2~dev/libgps/
/src/gpsd/fuzzer/
/src/gpsd/gpsd-3.26.2~dev/libgps/../include/

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
FuzzPacket fuzzerLogFile-0-tKiiM0KlwL.data fuzzerLogFile-0-tKiiM0KlwL.data.yaml FuzzPacket.covreport
FuzzJson fuzzerLogFile-0-epRUZFtmRq.data fuzzerLogFile-0-epRUZFtmRq.data.yaml FuzzJson.covreport