High level conclusions

Fuzzers reach 76.80% of cyclomatic complexity.

Fuzzers reach 69.33% of all functions.

Fuzzer mozjpeg_compression_fuzzer is blocked:

The runtime code coverage of mozjpeg_compression_fuzzer covers 17.88% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Fuzzer libjpegturbo_compression_fuzzer is blocked:

The runtime code coverage of libjpegturbo_compression_fuzzer covers 18.18% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Fuzzer libjpeg_compression_fuzzer is blocked:

The runtime code coverage of libjpeg_compression_fuzzer covers 18.18% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Reachability and coverage overview

Functions statically reachable by fuzzers

52 / 75

Cyclomatic complexity statically reachable by fuzzers

586 / 763

Runtime code coverage of functions

32 / 75

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: libjpeg_compression_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	209	64.1%
gold	[1:9]	16	4.90%
yellow	[10:29]	8	2.45%
greenyellow	[30:49]	21	6.44%
lawngreen	50+	72	22.0%
All colors	326	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
41	111	optimize	call site: 00111	strip_ai_markers
31	235	optimize	call site: 00235	copy_file
25	83	parse_markers	call site: 00083	valid_mpf_marker
16	300	rename_file	call site: 00300	delete_file
14	210	optimize	call site: 00210	patch_mpf_marker
8	38	optimize	call site: 00038	fprint_csv_field
7	175	optimize	call site: 00175	fatal
6	153	optimize	call site: 00153	strncopy
6	226	optimize	call site: 00226	fprintf
5	23	optimize	call site: 00023	warn
5	291	set_file_owner	call site: 00291	warn
4	161	optimize	call site: 00161	strncopy

Runtime coverage analysis

Covered functions

33

Functions that are reachable but not covered

99

Reachable functions

121

Percentage of reachable functions covered

18.18%

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
fuzz/fuzz_compression.c	1
fuzz/fuzz_manager.c	2
jpegoptim.c	5
misc.c	16
jpegsrc.c	2
jpegmarker.c	4
jpegmpf.c	8
/usr/include/x86_64-linux-gnu/bits/byteswap.h	2
/usr/include/x86_64-linux-gnu/bits/uintn-identity.h	2
stripai.c	9
jpegdest.c	2

Fuzzer: libjpegturbo_compression_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	208	63.8%
gold	[1:9]	16	4.90%
yellow	[10:29]	4	1.22%
greenyellow	[30:49]	4	1.22%
lawngreen	50+	94	28.8%
All colors	326	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
41	111	optimize	call site: 00111	strip_ai_markers
31	235	optimize	call site: 00235	copy_file
25	83	parse_markers	call site: 00083	valid_mpf_marker
16	300	rename_file	call site: 00300	delete_file
14	210	optimize	call site: 00210	patch_mpf_marker
8	38	optimize	call site: 00038	fprint_csv_field
7	175	optimize	call site: 00175	fatal
6	153	optimize	call site: 00153	strncopy
6	226	optimize	call site: 00226	fprintf
5	23	optimize	call site: 00023	warn
5	291	set_file_owner	call site: 00291	warn
4	161	optimize	call site: 00161	strncopy

Runtime coverage analysis

Covered functions

33

Functions that are reachable but not covered

99

Reachable functions

121

Percentage of reachable functions covered

18.18%

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
fuzz/fuzz_compression.c	1
fuzz/fuzz_manager.c	2
jpegoptim.c	5
misc.c	16
jpegsrc.c	2
jpegmarker.c	4
jpegmpf.c	8
/usr/include/x86_64-linux-gnu/bits/byteswap.h	2
/usr/include/x86_64-linux-gnu/bits/uintn-identity.h	2
stripai.c	9
jpegdest.c	2

Fuzzer: mozjpeg_compression_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	206	62.4%
gold	[1:9]	10	3.03%
yellow	[10:29]	8	2.42%
greenyellow	[30:49]	11	3.33%
lawngreen	50+	95	28.7%
All colors	330	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
41	111	optimize	call site: 00111	strip_ai_markers
31	239	optimize	call site: 00239	copy_file
25	83	parse_markers	call site: 00083	valid_mpf_marker
16	304	rename_file	call site: 00304	delete_file
14	214	optimize	call site: 00214	patch_mpf_marker
8	38	optimize	call site: 00038	fprint_csv_field
7	175	optimize	call site: 00175	fatal
6	153	optimize	call site: 00153	strncopy
6	230	optimize	call site: 00230	fprintf
5	23	optimize	call site: 00023	warn
5	295	set_file_owner	call site: 00295	warn
4	161	optimize	call site: 00161	strncopy

Runtime coverage analysis

Covered functions

33

Functions that are reachable but not covered

101

Reachable functions

123

Percentage of reachable functions covered

17.89%

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
fuzz/fuzz_compression.c	1
fuzz/fuzz_manager.c	2
jpegoptim.c	5
misc.c	16
jpegsrc.c	2
jpegmarker.c	4
jpegmpf.c	8
/usr/include/x86_64-linux-gnu/bits/byteswap.h	2
/usr/include/x86_64-linux-gnu/bits/uintn-identity.h	2
stripai.c	9
jpegdest.c	2

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
parse_arguments	/src/jpegoptim/jpegoptim.c	4	['int', 'N/A', 'N/A', 'size_t']	3	0	811	181	51	28	0	131	90
wait_for_worker	/src/jpegoptim/jpegoptim.c	1	['N/A']	2	0	484	89	31	14	0	60	39

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

Functions statically reachable by fuzzers

60 / 75

Cyclomatic complexity statically reachable by fuzzers

695 / 763

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

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.

fuzz/fuzz_compression.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=['optimize', 'parse_markers', 'rename_file']

fuzz/fuzz_compression.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=['optimize', 'parse_markers', 'rename_file']

fuzz/fuzz_compression.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=['optimize', 'parse_markers', 'rename_file']

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

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
	[]	[]
/usr/include/x86_64-linux-gnu/bits/uintn-identity.h	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	[]
/src/jpegoptim/jpegmarker.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/src/jpegoptim/fuzz/fuzz_manager.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/src/jpegoptim/jpegoptim.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/usr/include/x86_64-linux-gnu/bits/byteswap.h	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	[]
/src/jpegoptim/jpegsrc.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/src/jpegoptim/misc.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/src/jpegoptim/jpegdest.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/src/jpegoptim/fuzz/fuzz_compression.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']
/src/jpegoptim/jpegmpf.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	[]
/src/jpegoptim/stripai.c	['libjpeg_compression_fuzzer', 'libjpegturbo_compression_fuzzer', 'mozjpeg_compression_fuzzer']	[]

Directories in report

Directory
/src/jpegoptim/
/usr/include/x86_64-linux-gnu/bits/
/src/jpegoptim/fuzz/