High level conclusions

Fuzzers reach 56.05% code coverage.

Fuzzers reach 49.59% of cyclomatic complexity.

Fuzzers reach 54.53% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

999 / 1832

Cyclomatic complexity statically reachable by fuzzers

7647 / 15420

Runtime code coverage of functions

1027 / 1832

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: fuzz_regexp

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	213	35.6%
gold	[1:9]	5	0.83%
yellow	[10:29]	4	0.67%
greenyellow	[30:49]	5	0.83%
lawngreen	50+	370	61.9%
All colors	597	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
47	225	unicode_case1	call site: 00225	unicode_prop_ops
35	185	cr_op	call site: 00185	unicode_prop
18	158	re_string_list_free	call site: 00158	parse_unicode_property
14	322	lre_canonicalize	call site: 00322	parse_class_string_disjunction
14	371	re_parse_nested_class	call site: 00371	re_parse_class_set_operand
13	275	cr_op1	call site: 00275	re_string_list_canonicalize
10	408	re_emit_char	call site: 00408	re_emit_range
8	298	cr_regexp_canonicalize	call site: 00298	lre_case_conv_entry
8	343	get_class_atom	call site: 00343	re_string_list_canonicalize
7	400	re_emit_range	call site: 00400	rqsort
6	177	cr_add_interval	call site: 00177	cr_op
4	364	re_string_list_op	call site: 00364	re_string_find2

Runtime coverage analysis

Covered functions

105

Functions that are reachable but not covered

32

Reachable functions

135

Percentage of reachable functions covered

76.3%

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_regexp.c	4
libregexp.c	56
cutils.c	15
./cutils.h	14
./libunicode.h	7
libunicode.c	31

Fuzzer: fuzz_eval

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	3640	69.7%
gold	[1:9]	366	7.01%
yellow	[10:29]	549	10.5%
greenyellow	[30:49]	174	3.33%
lawngreen	50+	487	9.33%
All colors	5216	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
288	3930	lre_js_is_ident_next	call site: 03930	re_parse_disjunction
188	2820	JS_CallInternal	call site: 02820	js_binary_logic_slow
182	4851	js_std_add_helpers	call site: 04851	js_print
136	2290	JS_ConcatString3	call site: 02290	JS_DefinePropertyValue
104	3677	JS_AddIntrinsicDate	call site: 03677	js_Date_parse
81	2629	js_binary_arith_slow	call site: 02629	js_bigint_add
65	4721	ident_realloc	call site: 04721	json_parse_value
64	798	round_to_d	call site: 00798	js_new_string8_len
56	3075	js_async_function_resume	call site: 03075	js_promise_resolve
53	2226	JS_CallInternal	call site: 02226	JS_NewSymbolFromAtom
53	4252	re_parse_term	call site: 04252	re_emit_goto
49	3244	JS_EvalFunctionInternal	call site: 03244	JS_ThrowTypeError

Runtime coverage analysis

Covered functions

665

Functions that are reachable but not covered

476

Reachable functions

964

Percentage of reachable functions covered

50.62%

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_eval.c	1
quickjs.c	702
./list.h	6
./cutils.h	28
./quickjs.h	22
dtoa.c	37
cutils.c	19
./libunicode.h	9
libunicode.c	32
libregexp.c	49
fuzz/fuzz_common.c	3
quickjs-libc.c	32

Fuzzer: fuzz_compile

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	2518	44.4%
gold	[1:9]	170	3.00%
yellow	[10:29]	59	1.04%
greenyellow	[30:49]	9	0.15%
lawngreen	50+	2909	51.3%
All colors	5665	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
65	4721	ident_realloc	call site: 04721	json_parse_value
48	4468	JS_AddIntrinsicTypedArrays	call site: 04468	js_typed_array_constructor_obj
47	4055	unicode_case1	call site: 04055	unicode_prop_ops
45	4365	JS_AddIntrinsicMapSet	call site: 04365	js_create_from_ctor
36	2912	js_operator_in	call site: 02912	js_operator_private_in
35	2359	JS_CallInternal	call site: 02359	JS_GetPropertyValue
35	4015	cr_op	call site: 04015	unicode_prop
34	2972	JS_CallInternal	call site: 02972	JS_ToPropertyKey
33	4415	JS_AddIntrinsicTypedArrays	call site: 04415	js_array_buffer_constructor0
33	5329	JS_WriteArray	call site: 05329	JS_WriteObjectTag
32	5564	JS_ReadBigInt	call site: 05564	js_typed_array_constructor
31	2229	JS_CallInternal	call site: 02229	JS_GetPrivateField

Runtime coverage analysis

Covered functions

1036

Functions that are reachable but not covered

249

Reachable functions

1027

Percentage of reachable functions covered

75.75%

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.

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_compile.c	1
quickjs.c	764
./list.h	6
./cutils.h	29
./quickjs.h	22
dtoa.c	37
cutils.c	19
./libunicode.h	9
libunicode.c	32
libregexp.c	49
fuzz/fuzz_common.c	3
quickjs-libc.c	32

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
__JS_EvalInternal	/src/quickjs/quickjs.c	8	['N/A', 'size_t', 'size_t', 'N/A', 'size_t', 'N/A', 'int', 'int']	95	0	341	58	20	818	0	7450	2696
js_json_stringify	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	75	0	20	3	2	647	0	4939	306
js_regexp_Symbol_replace	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	68	0	777	127	51	650	0	5151	207
js_string_normalize	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	68	0	155	31	13	636	0	4773	126
js_os_exec	/src/quickjs/quickjs-libc.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	70	0	743	161	60	632	0	4732	110
js_typed_array_indexOf	/src/quickjs/quickjs.c	6	['N/A', 'size_t', 'size_t', 'int', 'N/A', 'int']	70	0	931	227	93	621	0	4732	104
js_set_difference	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	71	0	257	39	17	628	0	4731	90
JS_ComputeMemoryUsage	/src/quickjs/quickjs.c	2	['N/A', 'N/A']	3	0	1041	153	50	6	0	73	67
js_array_toSorted	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	72	0	239	43	17	622	0	4700	63
js_std_file_printf	/src/quickjs/quickjs-libc.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	72	0	29	6	3	625	0	4689	61

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

Functions statically reachable by fuzzers

1266 / 1832

Cyclomatic complexity statically reachable by fuzzers

11453 / 15420

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_regexp.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=['unicode_case1', 'cr_op', 're_string_list_free', 'lre_canonicalize', 're_parse_nested_class', 'cr_op1', 're_emit_char', 'cr_regexp_canonicalize', 'get_class_atom', 're_emit_range']

fuzz/fuzz_eval.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=['lre_js_is_ident_next', 'JS_CallInternal', 'js_std_add_helpers', 'JS_ConcatString3', 'JS_AddIntrinsicDate', 'js_binary_arith_slow', 'ident_realloc', 'round_to_d', 'js_async_function_resume']

fuzz/fuzz_compile.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=['ident_realloc', 'JS_AddIntrinsicTypedArrays', 'unicode_case1', 'JS_AddIntrinsicMapSet', 'js_operator_in', 'JS_CallInternal', 'cr_op', 'JS_WriteArray']

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
exchange_func	33	14	42.42%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
re_string_list_op	42	12	28.57%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
re_emit_string_list	64	9	14.06%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
js_os_poll	98	14	14.28%	['fuzz_eval', 'fuzz_compile']
JS_SetPropertyInternal	247	82	33.19%	['fuzz_eval', 'fuzz_compile']
JS_DefineProperty	262	95	36.25%	['fuzz_eval', 'fuzz_compile']
JS_GetOwnPropertyInternal	70	34	48.57%	['fuzz_eval', 'fuzz_compile']
JS_GetPropertyValue	66	30	45.45%	['fuzz_eval', 'fuzz_compile']
JS_ToInt64SatFree	38	13	34.21%	['fuzz_eval', 'fuzz_compile']
JS_GetIterator	31	15	48.38%	['fuzz_eval', 'fuzz_compile']
JS_IteratorNext2	31	17	54.83%	['fuzz_eval', 'fuzz_compile']
JS_CallConstructorInternal	40	16	40.0%	['fuzz_eval', 'fuzz_compile']
js_default_module_normalize_name	46	8	17.39%	['fuzz_eval', 'fuzz_compile']
js_inner_module_linking	130	69	53.07%	['fuzz_eval', 'fuzz_compile']
js_string_define_own_property	32	11	34.37%	['fuzz_eval', 'fuzz_compile']
js_promise_resolve_function_call	41	19	46.34%	['fuzz_eval', 'fuzz_compile']
fulfill_or_reject_promise	32	15	46.87%	['fuzz_eval', 'fuzz_compile']
js_async_function_resume	45	20	44.44%	['fuzz_eval', 'fuzz_compile']
js_parse_directives	77	26	33.76%	['fuzz_eval', 'fuzz_compile']
put_lvalue	109	53	48.62%	['fuzz_eval', 'fuzz_compile']
js_parse_import	125	29	23.20%	['fuzz_eval', 'fuzz_compile']
emit_return	68	27	39.70%	['fuzz_eval', 'fuzz_compile']
resolve_scope_var	423	217	51.30%	['fuzz_eval', 'fuzz_compile']
ss_check	33	17	51.51%	['fuzz_eval', 'fuzz_compile']
js_array_join	50	27	54.0%	['fuzz_eval', 'fuzz_compile']
u64toa_radix	31	4	12.90%	['fuzz_eval', 'fuzz_compile']
js_dtoa_max_len	39	15	38.46%	['fuzz_eval', 'fuzz_compile']
js_load_file	41	8	19.51%	['fuzz_eval', 'fuzz_compile']
js_module_loader	43	14	32.55%	['fuzz_eval', 'fuzz_compile']
JS_SetPrototypeInternal	86	36	41.86%	['fuzz_eval', 'fuzz_compile']
set_array_length	70	13	18.57%	['fuzz_eval', 'fuzz_compile']
JS_SetPropertyValue	112	34	30.35%	['fuzz_eval', 'fuzz_compile']
JS_ToArrayLengthFree	54	17	31.48%	['fuzz_eval', 'fuzz_compile']
js_print_value	116	26	22.41%	['fuzz_eval', 'fuzz_compile']
js_print_object	223	71	31.83%	['fuzz_eval', 'fuzz_compile']
js_dynamic_import	88	33	37.5%	['fuzz_eval', 'fuzz_compile']
JS_IteratorClose	35	16	45.71%	['fuzz_eval', 'fuzz_compile']
js_append_enumerate	64	17	26.56%	['fuzz_eval', 'fuzz_compile']
js_array_iterator_next	56	26	46.42%	['fuzz_eval', 'fuzz_compile']
js_bigint_pow	74	38	51.35%	['fuzz_eval', 'fuzz_compile']
js_bigint_float64_cmp	42	20	47.61%	['fuzz_eval', 'fuzz_compile']
JS_LoadModuleInternal	36	15	41.66%	['fuzz_eval', 'fuzz_compile']
JS_WriteObjectRec	134	57	42.53%	['fuzz_compile']
JS_WriteModule	44	17	38.63%	['fuzz_compile']
JS_ReadObjectRec	107	44	41.12%	['fuzz_compile']
JS_ReadModule	103	31	30.09%	['fuzz_compile']
js_regexp_Symbol_replace	174	58	33.33%	['fuzz_compile']
js_regexp_Symbol_match	73	26	35.61%	['fuzz_compile']
js_array_push	55	27	49.09%	['fuzz_compile']
js_obj_to_desc	75	25	33.33%	['fuzz_compile']
js_function_constructor	60	32	53.33%	['fuzz_eval', 'fuzz_compile']
js_date_constructor	56	28	50.0%	['fuzz_eval', 'fuzz_compile']
js_date_parse_otherstring	140	71	50.71%	['fuzz_eval', 'fuzz_compile']
js_parse_destructuring_element	403	201	49.87%	['fuzz_compile']
js_parse_class	435	204	46.89%	['fuzz_compile']
js_parse_delete	86	47	54.65%	['fuzz_compile']
js_parse_property_name	106	55	51.88%	['fuzz_compile']
emit_break	44	16	36.36%	['fuzz_compile']
resolve_pseudo_var	31	17	54.83%	['fuzz_compile']
js_error_constructor	64	28	43.75%	['fuzz_eval', 'fuzz_compile']
js_number_constructor	36	19	52.77%	['fuzz_eval', 'fuzz_compile']
js_string_replace	101	23	22.77%	['fuzz_compile']
JS_ToBigIntCtorFree	47	12	25.53%	['fuzz_eval', 'fuzz_compile']

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/quickjs/libunicode.c	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']
/src/quickjs/./cutils.h	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']	[]
/src/quickjs/fuzz/fuzz_common.c	['fuzz_eval', 'fuzz_compile']	['fuzz_eval', 'fuzz_compile']
/src/quickjs/libregexp.c	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']
/src/quickjs/fuzz/fuzz_regexp.c	['fuzz_regexp']	['fuzz_regexp']
/src/quickjs/quickjs-libc.c	['fuzz_eval', 'fuzz_compile']	['fuzz_eval', 'fuzz_compile']
/src/quickjs/./list.h	['fuzz_eval', 'fuzz_compile']	[]
/src/quickjs/quickjs.c	['fuzz_eval', 'fuzz_compile']	['fuzz_eval', 'fuzz_compile']
/src/quickjs/cutils.c	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']
/src/quickjs/dtoa.c	['fuzz_eval', 'fuzz_compile']	['fuzz_eval', 'fuzz_compile']
/src/quickjs/fuzz/fuzz_compile.c	['fuzz_compile']	['fuzz_compile']
/src/quickjs/./quickjs.h	['fuzz_eval', 'fuzz_compile']	[]
/src/quickjs/fuzz/fuzz_eval.c	['fuzz_eval']	['fuzz_eval']
/src/quickjs/./libunicode.h	['fuzz_regexp', 'fuzz_eval', 'fuzz_compile']	[]

Directories in report

Directory
/src/quickjs/./
/src/quickjs/fuzz/
/src/quickjs/