High level conclusions

Fuzzers reach 48.48% of cyclomatic complexity.

Fuzzers reach 83.33% of all functions.

Fuzzers reach 82.22% code coverage.

Reachability and coverage overview

Functions statically reachable by fuzzers

75 / 90

Cyclomatic complexity statically reachable by fuzzers

642 / 1324

Runtime code coverage of functions

74 / 90

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: libidn_stringprep_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	14	9.15%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	139	90.8%
All colors	153	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
4	114	str_cd_iconv	call site: 00114	__errno_location
3	110	str_cd_iconv	call site: 00110	__errno_location
1	10	rpl_free	call site: 00010	__errno_location
1	20	stringprep	call site: 00020	rpl_free
1	63	LLVMFuzzerTestOneInput	call site: 00063	rpl_free
1	78	LLVMFuzzerTestOneInput	call site: 00078	tld_get_table
1	105	str_cd_iconv	call site: 00105	__errno_location
1	124	str_iconv	call site: 00124	rpl_free
1	128	LLVMFuzzerTestOneInput	call site: 00128	strlen

Runtime coverage analysis

Covered functions

57

Functions that are reachable but not covered

15

Reachable functions

72

Percentage of reachable functions covered

79.17%

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/libidn/fuzz/libidn_stringprep_fuzzer.c	1
version.c	1
stringprep.c	9
gl/free.c	1
nfkc.c	18
gl/unistr/u8-check.c	1
idn-free.c	1
pr29.c	6
tld.c	12
toutf8.c	3
gl/striconv.c	2
gl/c-strcasecmp.c	1
gl/./c-ctype.h	1

Fuzzer: libidn_toascii_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	14	10.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	1	0.71%
greenyellow	[30:49]	1	0.71%
lawngreen	50+	123	88.4%
All colors	139	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
4	122	str_cd_iconv	call site: 00122	__errno_location
3	118	str_cd_iconv	call site: 00118	__errno_location
1	9	idna_to_ascii_4i	call site: 00009	rpl_free
1	11	rpl_free	call site: 00011	__errno_location
1	20	stringprep	call site: 00020	rpl_free
1	83	idna_to_ascii_4z	call site: 00083	rpl_free
1	88	LLVMFuzzerTestOneInput	call site: 00088	rpl_free
1	113	str_cd_iconv	call site: 00113	__errno_location
1	132	str_iconv	call site: 00132	rpl_free

Runtime coverage analysis

Covered functions

38

Functions that are reachable but not covered

14

Reachable functions

52

Percentage of reachable functions covered

73.08%

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/libidn/fuzz/libidn_toascii_fuzzer.c	1
idna.c	4
nfkc.c	14
gl/free.c	1
stringprep.c	6
gl/unistr/u8-check.c	1
punycode.c	4
idn-free.c	1
toutf8.c	3
gl/striconv.c	2
gl/c-strcasecmp.c	1
gl/./c-ctype.h	1

Fuzzer: libidn_tounicode_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	17	9.82%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	156	90.1%
All colors	173	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
4	148	str_cd_iconv	call site: 00148	__errno_location
3	144	str_cd_iconv	call site: 00144	__errno_location
2	104	idna_to_unicode_4z4z	call site: 00104	rpl_free
1	10	idna_to_unicode_internal	call site: 00010	rpl_free
1	12	rpl_free	call site: 00012	__errno_location
1	21	stringprep	call site: 00021	rpl_free
1	76	idna_to_ascii_4i	call site: 00076	rpl_free
1	100	LLVMFuzzerTestOneInput	call site: 00100	rpl_free
1	108	LLVMFuzzerTestOneInput	call site: 00108	rpl_free
1	139	str_cd_iconv	call site: 00139	__errno_location
1	158	str_iconv	call site: 00158	rpl_free

Runtime coverage analysis

Covered functions

46

Functions that are reachable but not covered

13

Reachable functions

59

Percentage of reachable functions covered

77.97%

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/libidn/fuzz/libidn_tounicode_fuzzer.c	1
idna.c	8
nfkc.c	14
gl/free.c	1
stringprep.c	6
gl/unistr/u8-check.c	1
gl/c-strncasecmp.c	1
gl/./c-ctype.h	1
punycode.c	6
gl/c-strcasecmp.c	1
idn-free.c	1
toutf8.c	4
gl/striconv.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

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

Functions statically reachable by fuzzers

75 / 90

Cyclomatic complexity statically reachable by fuzzers

642 / 1324

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.

/src/libidn/fuzz/libidn_stringprep_fuzzer.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=['str_cd_iconv', 'rpl_free', 'stringprep', 'LLVMFuzzerTestOneInput', 'str_iconv']

/src/libidn/fuzz/libidn_toascii_fuzzer.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=['str_cd_iconv', 'idna_to_ascii_4i', 'rpl_free', 'stringprep', 'idna_to_ascii_4z', 'LLVMFuzzerTestOneInput', 'str_iconv']

/src/libidn/fuzz/libidn_tounicode_fuzzer.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=['str_cd_iconv', 'idna_to_unicode_4z4z', 'idna_to_unicode_internal', 'rpl_free', 'stringprep', 'idna_to_ascii_4i', 'LLVMFuzzerTestOneInput']

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
str_cd_iconv	106	56	52.83%	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']

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/libidn/lib/toutf8.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/stringprep.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/idna.c	['libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/punycode.c	['libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/idn-free.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/tld.c	['libidn_stringprep_fuzzer']	['libidn_stringprep_fuzzer']
/src/libidn/fuzz/libidn_tounicode_fuzzer.c	['libidn_tounicode_fuzzer']	['libidn_tounicode_fuzzer']
/src/libidn/lib/gl/./c-ctype.h	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	[]
/src/libidn/lib/version.c	['libidn_stringprep_fuzzer']	['libidn_stringprep_fuzzer']
/src/libidn/fuzz/libidn_stringprep_fuzzer.c	['libidn_stringprep_fuzzer']	['libidn_stringprep_fuzzer']
/src/libidn/lib/nfkc.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/gl/c-strcasecmp.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/fuzz/libidn_toascii_fuzzer.c	['libidn_toascii_fuzzer']	['libidn_toascii_fuzzer']
/src/libidn/lib/gl/unistr/u8-check.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/gl/free.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']
/src/libidn/lib/gl/c-strncasecmp.c	['libidn_tounicode_fuzzer']	['libidn_tounicode_fuzzer']
/src/libidn/lib/pr29.c	['libidn_stringprep_fuzzer']	['libidn_stringprep_fuzzer']
/src/libidn/lib/gl/striconv.c	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']	['libidn_stringprep_fuzzer', 'libidn_toascii_fuzzer', 'libidn_tounicode_fuzzer']

Directories in report

Directory
/src/libidn/lib/gl/
/src/libidn/lib/
/src/libidn/lib/gl/./
/src/libidn/fuzz/
/src/libidn/lib/gl/unistr/