High level conclusions

Fuzzers reach 86.93% code coverage.

Fuzzers reach 54.22% of cyclomatic complexity.

Fuzzers reach 43.21% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

86 / 199

Cyclomatic complexity statically reachable by fuzzers

584 / 1077

Runtime code coverage of functions

173 / 199

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.

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: iccprofile_info

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	18	9.57%
gold	[1:9]	0	0.0%
yellow	[10:29]	1	0.53%
greenyellow	[30:49]	5	2.65%
lawngreen	50+	164	87.2%
All colors	188	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
16	103	fit_linear(skcms_Curve const*, int, float, float*, float*, float*)	call site: 00103	skcms_TransferFunction_eval
1	71	bool read_tag_mft1 (skcms_ICCTag const*, skcms_A2B*)	call site: 00071
1	138	bool read_tag_mft1 (skcms_ICCTag const*, skcms_B2A*)	call site: 00138

Runtime coverage analysis

Covered functions

41

Functions that are reachable but not covered

13

Reachable functions

88

Percentage of reachable functions covered

85.23%

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_iccprofile_info.c	2
fuzz/../src/skcms_public.h	1
skcms.cc	43
./src/skcms_internals.h	2

Fuzzer: iccprofile_atf

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	13	5.28%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	233	94.7%
All colors	246	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
3	111	powf_	call site: 00111	powf_
3	116	skcms_TransferFunction_eval	call site: 00116	powf_
2	105	skcms_TransferFunction_eval	call site: 00105
1	71	bool read_tag_mft1 (skcms_ICCTag const*, skcms_A2B*)	call site: 00071
1	103	fit_linear(skcms_Curve const*, int, float, float*, float*, float*)	call site: 00103	skcms_TransferFunction_eval
1	108	exp2f_(float)	call site: 00108	powf_
1	138	bool read_tag_mft1 (skcms_ICCTag const*, skcms_B2A*)	call site: 00138
1	240	skcms_ApproximateCurve	call site: 00240	__assert_fail

Runtime coverage analysis

Covered functions

56

Functions that are reachable but not covered

3

Reachable functions

104

Percentage of reachable functions covered

97.12%

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
fuzz/fuzz_iccprofile_atf.c	1
fuzz/../src/skcms_public.h	1
skcms.cc	53
./src/skcms_internals.h	2

Fuzzer: iccprofile_transform

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	83	20.8%
gold	[1:9]	0	0.0%
yellow	[10:29]	13	3.25%
greenyellow	[30:49]	10	2.50%
lawngreen	50+	293	73.4%
All colors	399	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
21	292	skcms_Transform	call site: 00292	skcms_sRGB_TransferFunction
16	374	skcms_Transform	call site: 00374	skcms_sRGB_Inverse_TransferFunction
8	283	skcms_Transform	call site: 00283	skcms_sRGB_profile
7	332	skcms_Transform::$_2::operator()(skcms_Curve const*, int) const	call site: 00332	memcmp
7	366	skcms_Transform	call site: 00366
3	111	powf_	call site: 00111	powf_
3	116	skcms_TransferFunction_eval	call site: 00116	powf_
3	321	skcms_Transform	call site: 00321
2	105	skcms_TransferFunction_eval	call site: 00105
2	318	skcms_Transform	call site: 00318
1	71	bool read_tag_mft1 (skcms_ICCTag const*, skcms_A2B*)	call site: 00071
1	103	fit_linear(skcms_Curve const*, int, float, float*, float*, float*)	call site: 00103	skcms_TransferFunction_eval

Runtime coverage analysis

Covered functions

200

Functions that are reachable but not covered

14

Reachable functions

154

Percentage of reachable functions covered

90.91%

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
fuzz/fuzz_iccprofile_transform.c	1
fuzz/../src/skcms_public.h	1
skcms.cc	79
./src/skcms_internals.h	2
./src/skcms_public.h	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
skcms_GetInputChannelCount	/src/skcms/skcms.cc	1	['N/A']	2	0	136	28	11	7	0	50	39

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

Functions statically reachable by fuzzers

88 / 199

Cyclomatic complexity statically reachable by fuzzers

623 / 1077

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_iccprofile_info.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=['fit_linear(skcms_Curve const*, int, float, float*, float*, float*)', 'bool read_tag_mft1(skcms_ICCTag const*, skcms_A2B*)', 'bool read_tag_mft1(skcms_ICCTag const*, skcms_B2A*)']

fuzz/fuzz_iccprofile_atf.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=['powf_', 'skcms_TransferFunction_eval', 'bool read_tag_mft1(skcms_ICCTag const*, skcms_A2B*)', 'fit_linear(skcms_Curve const*, int, float, float*, float*, float*)', 'exp2f_(float)', 'bool read_tag_mft1(skcms_ICCTag const*, skcms_B2A*)', 'skcms_ApproximateCurve']

fuzz/fuzz_iccprofile_transform.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=['skcms_Transform', 'skcms_Transform::$_2::operator()(skcms_Curve const*, int) const', 'powf_', 'skcms_TransferFunction_eval']

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
skcms_TransferFunction_eval	42	11	26.19%	['iccprofile_transform', 'iccprofile_info', 'iccprofile_atf']

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/skcms/skcms.cc	['iccprofile_info', 'iccprofile_atf', 'iccprofile_transform']	['iccprofile_info', 'iccprofile_atf', 'iccprofile_transform']
/src/skcms/fuzz/fuzz_iccprofile_atf.c	['iccprofile_atf']	['iccprofile_atf']
/src/skcms/./src/skcms_public.h	['iccprofile_transform']	[]
/src/skcms/fuzz/../src/skcms_public.h	['iccprofile_info', 'iccprofile_atf', 'iccprofile_transform']	[]
/src/skcms/src/Transform_inl.h	[]	[]
/src/skcms/fuzz/fuzz_iccprofile_info.c	['iccprofile_info']	['iccprofile_info']
/src/skcms/./src/skcms_internals.h	['iccprofile_info', 'iccprofile_atf', 'iccprofile_transform']	[]
/src/skcms/fuzz/fuzz_iccprofile_transform.c	['iccprofile_transform']	['iccprofile_transform']

Directories in report

Directory
/src/skcms/fuzz/
/src/skcms/src/
/src/skcms/
/src/skcms/fuzz/../src/
/src/skcms/./src/