High level conclusions

Fuzzers reach 67.06% code coverage.

Fuzzers reach 62.78% of cyclomatic complexity.

Fuzzers reach 68.67% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

171 / 249

Cyclomatic complexity statically reachable by fuzzers

1198 / 1908

Runtime code coverage of functions

167 / 249

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: json_equal_copy_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	22	5.89%
gold	[1:9]	19	5.09%
yellow	[10:29]	10	2.68%
greenyellow	[30:49]	18	4.82%
lawngreen	50+	304	81.5%
All colors	373	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	145	seed_from_urandom	call site: 00145	seed_from_timestamp_and_pid
2	7	jsonp_error_set_source	call site: 00007	error_set
2	233	hashtable_set	call site: 00233	json_decref
1	46	stream_unget	call site: 00046	__assert_fail
1	48	lex_unget_unsave	call site: 00048	__assert_fail
1	62	decode_unicode_escape	call site: 00062	error_set
1	64	lex_scan_string	call site: 00064	error_set
1	70	lex_scan_string	call site: 00070	__assert_fail
1	100	get_decimal_point	call site: 00100	strchr
1	124	string_create	call site: 00124	jsonp_free
1	154	hashtable_init	call site: 00154	jsonp_free
1	179	json_array	call site: 00179	jsonp_free

Runtime coverage analysis

Covered functions

129

Functions that are reachable but not covered

20

Reachable functions

151

Percentage of reachable functions covered

86.75%

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
test/ossfuzz/json_equal_copy_fuzzer.cc	2
src/load.c	24
src/error.c	4
src/strbuffer.c	7
src/memory.c	4
src/utf.c	3
src/strconv.c	3
src/value.c	52
src/hashtable_seed.c	5
src/hashtable.c	20
src/./lookup3.h	1
src/./jansson.h	4
test/ossfuzz/../../src/jansson.h	1

Fuzzer: json_load_dump_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	69	16.9%
gold	[1:9]	20	4.91%
yellow	[10:29]	3	0.73%
greenyellow	[30:49]	8	1.96%
lawngreen	50+	307	75.4%
All colors	407	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	308	diff	call site: 00308	lshift
7	284	pow5mult	call site: 00284	pow5mult
7	295	lshift	call site: 00295	lshift
5	260	jsonp_dtostr	call site: 00260	nrv_alloc
4	148	seed_from_urandom	call site: 00148	seed_from_timestamp_and_pid
3	276	pow5mult	call site: 00276	Balloc
2	10	jsonp_error_set_source	call site: 00010	error_set
2	124	jsonp_stringn_nocheck_own	call site: 00124	jsonp_strndup
2	236	hashtable_set	call site: 00236	json_decref
2	303	quorem	call site: 00303	diff
1	49	stream_unget	call site: 00049	__assert_fail
1	51	lex_unget_unsave	call site: 00051	__assert_fail

Runtime coverage analysis

Covered functions

133

Functions that are reachable but not covered

25

Reachable functions

159

Percentage of reachable functions covered

84.28%

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
test/ossfuzz/json_load_dump_fuzzer.cc	2
src/load.c	24
src/error.c	4
src/strbuffer.c	8
src/memory.c	4
src/utf.c	4
src/strconv.c	4
src/value.c	33
src/hashtable_seed.c	5
src/hashtable.c	20
src/./lookup3.h	1
src/./jansson.h	1
src/dump.c	7
src/dtoa.c	17
test/ossfuzz/../../src/jansson.h	1

Fuzzer: json_pack_unpack_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	129	24.2%
gold	[1:9]	21	3.94%
yellow	[10:29]	8	1.50%
greenyellow	[30:49]	3	0.56%
lawngreen	50+	371	69.7%
All colors	532	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	482	unpack_array	call site: 00482	set_error
16	355	diff	call site: 00355	lshift
14	510	unpack_object	call site: 00510	hashtable_get
7	331	pow5mult	call site: 00331	pow5mult
7	342	lshift	call site: 00342	lshift
5	307	jsonp_dtostr	call site: 00307	nrv_alloc
5	460	unpack_object	call site: 00460	set_error
4	143	seed_from_urandom	call site: 00143	seed_from_timestamp_and_pid
4	445	json_unpack	call site: 00445	jsonp_error_init
3	323	pow5mult	call site: 00323	Balloc
2	5	jsonp_error_set_source	call site: 00005	error_set
2	165	hashtable_find_pair	call site: 00165	error_set

Runtime coverage analysis

Covered functions

151

Functions that are reachable but not covered

26

Reachable functions

177

Percentage of reachable functions covered

85.31%

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
test/ossfuzz/json_pack_unpack_fuzzer.cc	1
src/load.c	26
src/error.c	4
src/strbuffer.c	8
src/memory.c	4
src/utf.c	4
src/strconv.c	4
src/value.c	43
src/hashtable_seed.c	5
src/hashtable.c	20
src/./lookup3.h	1
src/./jansson.h	2
test/ossfuzz/../../src/jansson.h	1
src/dump.c	7
src/dtoa.c	17
src/pack_unpack.c	9

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
strtod__unused	/src/jansson/src/dtoa.c	2	['N/A', 'N/A']	5	0	3779	694	237	29	0	503	402
pack_object	/src/jansson/src/pack_unpack.c	2	['N/A', 'N/A']	15	0	210	33	13	74	6	344	100

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

Functions statically reachable by fuzzers

194 / 249

Cyclomatic complexity statically reachable by fuzzers

1687 / 1908

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.

test/ossfuzz/json_equal_copy_fuzzer.cc

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=['seed_from_urandom', 'jsonp_error_set_source', 'hashtable_set', 'stream_unget', 'lex_unget_unsave', 'decode_unicode_escape', 'lex_scan_string', 'get_decimal_point', 'string_create']

test/ossfuzz/json_load_dump_fuzzer.cc

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=['diff', 'pow5mult', 'lshift', 'jsonp_dtostr', 'seed_from_urandom', 'jsonp_error_set_source', 'jsonp_stringn_nocheck_own', 'hashtable_set', 'quorem']

test/ossfuzz/json_pack_unpack_fuzzer.cc

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=['unpack_array', 'diff', 'unpack_object', 'pow5mult', 'lshift', 'jsonp_dtostr', 'seed_from_urandom', 'json_unpack']

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
hashlittle	118	49	41.52%	['json_load_dump_fuzzer', 'json_equal_copy_fuzzer', 'json_pack_unpack_fuzzer']
unpack	127	15	11.81%	['json_pack_unpack_fuzzer']
unpack_object	105	41	39.04%	['json_pack_unpack_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/jansson/src/strconv.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/hashtable.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/test/ossfuzz/../../src/jansson.h	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	[]
/src/jansson/src/hashtable_seed.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/./lookup3.h	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	[]
/src/jansson/src/error.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/load.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/dump.c	['json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/test/ossfuzz/json_equal_copy_fuzzer.cc	['json_equal_copy_fuzzer']	['json_equal_copy_fuzzer']
/src/jansson/src/memory.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/value.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/dtoa.c	['json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/utf.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/src/./jansson.h	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	[]
/src/jansson/src/pack_unpack.c	['json_pack_unpack_fuzzer']	['json_pack_unpack_fuzzer']
/src/jansson/test/ossfuzz/json_load_dump_fuzzer.cc	['json_load_dump_fuzzer']	['json_load_dump_fuzzer']
/src/jansson/src/strbuffer.c	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']	['json_equal_copy_fuzzer', 'json_load_dump_fuzzer', 'json_pack_unpack_fuzzer']
/src/jansson/test/ossfuzz/json_pack_unpack_fuzzer.cc	['json_pack_unpack_fuzzer']	['json_pack_unpack_fuzzer']

Directories in report

Directory
/src/jansson/src/./
/src/jansson/test/ossfuzz/
/src/jansson/test/ossfuzz/../../src/
/src/jansson/src/