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

Table of contents

Project overview: openjpeg
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: opj_decompress_fuzzer_J2K
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Fuzzer: opj_decompress_fuzzer_JP2
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
./tests/fuzzers/opj_decompress_fuzzer_J2K.cpp
Dictionary
Fuzzer function priority
./tests/fuzzers/opj_decompress_fuzzer_JP2.cpp
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: 2026-01-09

Project overview: openjpeg

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
11.0%
69 / 652
Cyclomatic complexity statically reachable by fuzzers
4.0%
330 / 8107
Runtime code coverage of functions
52.0%
342 / 652

Warning: The number of runtime covered functions are larger than the number of reachable functions. This means that Fuzz Introspector found there are more functions covered at runtime than what is considered reachable based on the static analysis. This is a limitation in the analysis as anything covered at runtime is by definition reachable by the fuzzers.
This is likely due to a limitation in the static analysis. In this case, the count of functions covered at runtime is the true value, which means this is what should be considered "achieved" by the fuzzer.

Use the project functions table below to query all functions that were not covered at runtime.

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
opj_decompress_fuzzer_J2K ./tests/fuzzers/opj_decompress_fuzzer_J2K.cpp 95 602 8 12 767 377 opj_decompress_fuzzer_J2K.cpp
opj_decompress_fuzzer_JP2 ./tests/fuzzers/opj_decompress_fuzzer_JP2.cpp 95 602 8 12 767 377 opj_decompress_fuzzer_JP2.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: opj_decompress_fuzzer_J2K

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 0 238 100.%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 0 0.0%
All colors 238 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
237 0 EP call site: 00000 opj_create_decompress

Runtime coverage analysis

Covered functions
1
Functions that are reachable but not covered
95
Reachable functions
95
Percentage of reachable functions covered
0.0%
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
./tests/fuzzers/opj_decompress_fuzzer_J2K.cpp 7
src/lib/openjp2/openjpeg.c 12
src/lib/openjp2/opj_malloc.c 4
src/lib/openjp2/j2k.c 9
src/lib/openjp2/function_list.c 2
src/lib/openjp2/thread.c 21
src/lib/openjp2/tcd.c 2
src/lib/openjp2/tgt.c 1
src/lib/openjp2/image.c 1
src/lib/openjp2/jp2.c 2
src/lib/openjp2/event.c 2
src/lib/openjp2/cio.c 7

Fuzzer: opj_decompress_fuzzer_JP2

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 95 39.9%
gold [1:9] 0 0.0%
yellow [10:29] 3 1.26%
greenyellow [30:49] 1 0.42%
lawngreen 50+ 139 58.4%
All colors 238 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
25 76 opj_tls_destroy call site: 00076 opj_thread_pool_destroy
11 32 opj_mutex_create call site: 00032 opj_thread_pool_setup
11 45 opj_mutex_destroy call site: 00045 opj_worker_thread_function
10 64 opj_mutex_unlock call site: 00064 opj_tls_destroy
8 173 opj_jp2_create call site: 00173 opj_j2k_create_compress
6 57 opj_mutex_lock call site: 00057 opj_cond_signal
4 20 opj_j2k_get_default_thread_count call site: 00020 opj_get_num_cpus
3 124 opj_j2k_destroy call site: 00124 opj_free
2 28 opj_tls_new call site: 00028 opj_mutex_create
2 104 opj_thread_pool_destroy call site: 00104 opj_j2k_destroy
1 4 opj_calloc call site: 00004 opj_j2k_create_decompress
1 11 opj_j2k_create_cstr_index call site: 00011 opj_free

Runtime coverage analysis

Covered functions
346
Functions that are reachable but not covered
32
Reachable functions
95
Percentage of reachable functions covered
66.32%
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.
Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
./tests/fuzzers/opj_decompress_fuzzer_JP2.cpp 7
src/lib/openjp2/openjpeg.c 12
src/lib/openjp2/opj_malloc.c 4
src/lib/openjp2/j2k.c 9
src/lib/openjp2/function_list.c 2
src/lib/openjp2/thread.c 21
src/lib/openjp2/tcd.c 2
src/lib/openjp2/tgt.c 1
src/lib/openjp2/image.c 1
src/lib/openjp2/jp2.c 2
src/lib/openjp2/event.c 2
src/lib/openjp2/cio.c 7

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
opj_jp2_decode /src/openjpeg/src/lib/openjp2/jp2.c 4 ['N/A', 'N/A', 'N/A', 'N/A'] 13 0 33 8 4 254 0 4446 4360
opj_jp2_encode /src/openjpeg/src/lib/openjp2/jp2.c 3 ['N/A', 'N/A', 'N/A'] 13 0 13 3 2 188 0 1847 1331
opj_jp2_setup_encoder /src/openjpeg/src/lib/openjp2/jp2.c 4 ['N/A', 'N/A', 'N/A', 'N/A'] 4 0 645 118 48 33 0 525 492
opj_jp2_start_compress /src/openjpeg/src/lib/openjp2/jp2.c 4 ['N/A', 'N/A', 'N/A', 'N/A'] 8 0 55 12 6 99 0 562 388
opj_jp2_read_header /src/openjpeg/src/lib/openjp2/jp2.c 4 ['N/A', 'N/A', 'N/A', 'N/A'] 7 0 146 33 16 47 0 315 176
opj_j2k_read_siz /src/openjpeg/src/lib/openjp2/j2k.c 4 ['N/A', 'N/A', 'int', 'N/A'] 3 0 700 130 55 12 0 101 65
jp2_dump /src/openjpeg/src/lib/openjp2/jp2.c 3 ['N/A', 'int', 'N/A'] 4 0 13 3 2 10 0 67 65
opj_jp2_get_tile /src/openjpeg/src/lib/openjp2/jp2.c 5 ['N/A', 'N/A', 'N/A', 'N/A', 'int'] 13 0 34 8 4 251 0 4384 47
opj_j2k_read_cod /src/openjpeg/src/lib/openjp2/j2k.c 4 ['N/A', 'N/A', 'int', 'N/A'] 3 0 230 42 17 5 0 64 44
opj_jp2_end_compress /src/openjpeg/src/lib/openjp2/jp2.c 3 ['N/A', 'N/A', 'N/A'] 7 0 37 8 4 30 0 138 43

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

Functions statically reachable by fuzzers
79.0%
517 / 652
Cyclomatic complexity statically reachable by fuzzers
90.0%
7315 / 8107

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/fuzzers/opj_decompress_fuzzer_J2K.cpp

Dictionary

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


./tests/fuzzers/opj_decompress_fuzzer_JP2.cpp

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=['opj_tls_destroy', 'opj_mutex_create', 'opj_mutex_destroy', 'opj_mutex_unlock', 'opj_jp2_create', 'opj_mutex_lock', 'opj_j2k_get_default_thread_count', 'opj_j2k_destroy', 'opj_tls_new', 'opj_thread_pool_destroy']

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
opj_dwt_decode_tile 125 53 42.4% ['opj_decompress_fuzzer_JP2']
opj_j2k_read_header 35 19 54.28% ['opj_decompress_fuzzer_JP2']
opj_j2k_set_decode_area 122 60 49.18% ['opj_decompress_fuzzer_JP2']
opj_j2k_decode 37 16 43.24% ['opj_decompress_fuzzer_JP2']
opj_j2k_move_data_from_codec_to_output_image 47 14 29.78% ['opj_decompress_fuzzer_JP2']
opj_create_decompress 158 79 50.0% ['opj_decompress_fuzzer_JP2', 'opj_decompress_fuzzer_J2K']
opj_thread_pool_submit_job 48 7 14.58% ['opj_decompress_fuzzer_JP2']

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/openjpeg/src/lib/openjp2/sparse_array.c [] []
/src/openjpeg/./tests/fuzzers/opj_decompress_fuzzer_JP2.cpp ['opj_decompress_fuzzer_JP2'] []
/src/openjpeg/src/lib/openjp2/bio.c [] []
/src/openjpeg/src/lib/openjp2/opj_includes.h [] []
/src/openjpeg/src/lib/openjp2/pi.c [] []
/src/openjpeg/src/lib/openjp2/j2k.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/dwt.c [] []
/src/openjpeg/src/lib/openjp2/t1.c [] []
/src/openjpeg/src/lib/openjp2/mct.c [] []
/src/openjpeg/src/lib/openjp2/image.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/tgt.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/./tests/fuzzers/opj_decompress_fuzzer_J2K.cpp ['opj_decompress_fuzzer_J2K'] []
/src/openjpeg/src/lib/openjp2/function_list.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/mqc_inl.h [] []
/src/openjpeg/src/lib/openjp2/invert.c [] []
/src/openjpeg/src/lib/openjp2/t2.c [] []
/src/openjpeg/src/lib/openjp2/tcd.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/cio.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/jp2.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/thread.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/ht_dec.c [] []
/src/openjpeg/src/lib/openjp2/opj_intmath.h [] []
/src/openjpeg/src/lib/openjp2/mqc.c [] []
/src/openjpeg/src/lib/openjp2/event.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/opj_malloc.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']
/src/openjpeg/src/lib/openjp2/openjpeg.c ['opj_decompress_fuzzer_J2K', 'opj_decompress_fuzzer_JP2'] ['opj_decompress_fuzzer_JP2']

Directories in report

Directory
/src/openjpeg/src/lib/openjp2/
/src/openjpeg/./tests/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
opj_decompress_fuzzer_J2K fuzzerLogFile-0-DRD6ycyA8O.data fuzzerLogFile-0-DRD6ycyA8O.data.yaml opj_decompress_fuzzer_J2K.covreport
opj_decompress_fuzzer_JP2 fuzzerLogFile-0-YOXKwBsEWV.data fuzzerLogFile-0-YOXKwBsEWV.data.yaml opj_decompress_fuzzer_JP2.covreport