High level conclusions

Fuzzers reach 49.29% of cyclomatic complexity.

Fuzzers reach 54.05% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

1020 / 1887

Cyclomatic complexity statically reachable by fuzzers

7860 / 15945

Runtime code coverage of functions

784 / 1887

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	381	62.7%
gold	[1:9]	83	13.6%
yellow	[10:29]	4	0.65%
greenyellow	[30:49]	2	0.32%
lawngreen	50+	137	22.5%
All colors	607	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	238	unicode_case1	call site: 00238	unicode_prop_ops
35	81	lre_parse_escape	call site: 00081	lre_js_is_ident_next
35	198	cr_op	call site: 00198	unicode_prop
29	575	lre_exec_backtrack	call site: 00575	lre_canonicalize
22	123	re_parse_term	call site: 00123	re_has_named_captures
18	171	re_string_list_free	call site: 00171	parse_unicode_property
16	384	re_parse_nested_class	call site: 00384	re_parse_class_set_operand
14	335	lre_canonicalize	call site: 00335	parse_class_string_disjunction
13	288	cr_op1	call site: 00288	re_string_list_canonicalize
13	421	re_emit_char	call site: 00421	re_emit_range
10	532	lre_exec_backtrack	call site: 00532	lre_is_space
9	373	re_parse_nested_class	call site: 00373	re_string_list_op

Runtime coverage analysis

Covered functions

83

Functions that are reachable but not covered

58

Reachable functions

139

Percentage of reachable functions covered

58.27%

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	57
cutils.c	14
./cutils.h	14
./libunicode.h	10
libunicode.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	4207	72.1%
gold	[1:9]	1018	17.4%
yellow	[10:29]	195	3.34%
greenyellow	[30:49]	51	0.87%
lawngreen	50+	357	6.12%
All colors	5828	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
531	2562	JS_DefinePropertyValueUint32	call site: 02562	JS_IteratorNext
404	4034	lre_js_is_ident_next	call site: 04034	js_regexp_set_internal
194	2309	JS_CallInternal	call site: 02309	JS_NewSymbolFromAtom
183	5003	js_std_add_helpers	call site: 05003	js_print
158	2135	JS_CallInternal	call site: 02135	JS_ThrowInternalError
101	4835	string_buffer_putc_slow	call site: 04835	json_parse_value
100	5672	JS_ReadModule	call site: 05672	JS_ReadObjectRec
77	3218	js_async_function_call	call site: 03218	JS_NewCFunctionData
75	2059	JS_CallInternal	call site: 02059	JS_ThrowReferenceErrorUninitialized2
75	4585	JS_AddIntrinsicTypedArrays	call site: 04585	js_typed_array_constructor_obj
74	1684	JS_ToInt32	call site: 01684	JS_ToNumberFree
72	3952	dbuf_put_u32	call site: 03952	re_parse_disjunction

Runtime coverage analysis

Covered functions

595

Functions that are reachable but not covered

589

Reachable functions

1048

Percentage of reachable functions covered

43.8%

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_compile.c	1
quickjs.c	783
./list.h	6
./cutils.h	29
./quickjs.h	23
dtoa.c	37
cutils.c	18
./libunicode.h	9
libunicode.c	32
libregexp.c	51
fuzz/fuzz_common.c	3
quickjs-libc.c	32

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	3627	67.5%
gold	[1:9]	417	7.76%
yellow	[10:29]	727	13.5%
greenyellow	[30:49]	67	1.24%
lawngreen	50+	534	9.94%
All colors	5372	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
297	4036	lre_is_id_continue	call site: 04036	re_parse_disjunction
186	2905	JS_CallInternal	call site: 02905	js_binary_logic_slow
183	5003	js_std_add_helpers	call site: 05003	js_print
130	2373	JS_ConcatString3	call site: 02373	JS_DefinePropertyValue
104	3779	JS_AddIntrinsicDate	call site: 03779	js_Date_parse
91	4845	ident_realloc	call site: 04845	json_parse_value
71	2724	js_binary_arith_slow	call site: 02724	js_bigint_add
58	3159	js_async_function_resume	call site: 03159	js_promise_resolve
52	4585	JS_AddIntrinsicTypedArrays	call site: 04585	js_typed_array_constructor_obj
49	1025	JS_NewObject	call site: 01025	js_build_arguments
49	1811	js_atof	call site: 01811	JS_ThrowOutOfMemory
49	3329	JS_EvalFunctionInternal	call site: 03329	JS_ThrowTypeError

Runtime coverage analysis

Covered functions

705

Functions that are reachable but not covered

477

Reachable functions

985

Percentage of reachable functions covered

51.57%

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	721
./list.h	6
./cutils.h	28
./quickjs.h	23
dtoa.c	37
cutils.c	18
./libunicode.h	9
libunicode.c	32
libregexp.c	51
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']	96	0	341	58	20	824	0	7565	2753
js_regexp_Symbol_replace	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	70	0	764	125	50	658	0	5282	310
js_json_to_str	/src/quickjs/quickjs.c	5	['N/A', 'N/A', 'size_t', 'size_t', 'N/A']	75	0	781	139	54	647	3	4979	252
js_string_normalize	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	69	0	157	31	13	640	0	4834	127
js_typed_array_indexOf	/src/quickjs/quickjs.c	6	['N/A', 'size_t', 'size_t', 'int', 'N/A', 'int']	71	0	929	227	93	625	0	4792	115
js_os_exec	/src/quickjs/quickjs-libc.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	71	0	749	163	61	639	0	4801	111
js_set_difference	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	72	0	257	39	17	632	0	4791	90

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

Functions statically reachable by fuzzers

1276 / 1887

Cyclomatic complexity statically reachable by fuzzers

11540 / 15945

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', 'lre_parse_escape', 'cr_op', 'lre_exec_backtrack', 're_parse_term', 're_string_list_free', 're_parse_nested_class', 'lre_canonicalize', 'cr_op1', 're_emit_char']

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=['JS_DefinePropertyValueUint32', 'lre_js_is_ident_next', 'JS_CallInternal', 'js_std_add_helpers', 'string_buffer_putc_slow', 'JS_ReadModule', 'js_async_function_call', 'JS_AddIntrinsicTypedArrays']

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_is_id_continue', 'JS_CallInternal', 'js_std_add_helpers', 'JS_ConcatString3', 'JS_AddIntrinsicDate', 'ident_realloc', 'js_binary_arith_slow', 'js_async_function_resume', 'JS_AddIntrinsicTypedArrays', 'JS_NewObject']

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']
lre_parse_escape	108	49	45.37%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
re_parse_term	471	241	51.16%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
re_parse_nested_class	142	59	41.54%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
get_class_atom	165	85	51.51%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
re_emit_string_list	64	9	14.06%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
re_need_check_adv_and_capture_init	67	35	52.23%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
js_os_poll	98	14	14.28%	['fuzz_eval', 'fuzz_compile']
JS_ExecutePendingJob	31	10	32.25%	['fuzz_eval', 'fuzz_compile']
JS_GetPropertyInternal	138	67	48.55%	['fuzz_eval', 'fuzz_compile']
JS_SetPropertyInternal	247	57	23.07%	['fuzz_eval', 'fuzz_compile']
JS_DefineProperty	262	89	33.96%	['fuzz_eval', 'fuzz_compile']
JS_GetOwnPropertyNamesInternal	180	74	41.11%	['fuzz_eval', 'fuzz_compile']
JS_GetOwnPropertyInternal	70	21	30.0%	['fuzz_eval', 'fuzz_compile']
JS_ToStringInternal	54	23	42.59%	['fuzz_eval', 'fuzz_compile']
js_call_c_function	112	51	45.53%	['fuzz_eval', 'fuzz_compile']
JS_CallInternal	2600	598	23.0%	['fuzz_eval', 'fuzz_compile']
js_host_resolve_imported_module	39	17	43.58%	['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_WriteObjectRec	134	25	18.65%	['fuzz_compile']
JS_WriteModule	44	17	38.63%	['fuzz_compile']
JS_ReadObjectRec	107	27	25.23%	['fuzz_compile']
JS_ReadModule	103	25	24.27%	['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_date_parse_isostring	54	12	22.22%	['fuzz_eval', 'fuzz_compile']
js_date_parse_otherstring	140	42	30.0%	['fuzz_eval', 'fuzz_compile']
next_token	417	191	45.80%	['fuzz_eval', 'fuzz_compile']
js_parse_string	120	60	50.0%	['fuzz_eval', 'fuzz_compile']
js_parse_postfix_expr	579	182	31.43%	['fuzz_eval', 'fuzz_compile']
js_parse_assign_expr2	236	46	19.49%	['fuzz_eval', 'fuzz_compile']
js_parse_logical_and_or	35	12	34.28%	['fuzz_eval', 'fuzz_compile']
js_parse_expr_binary	161	76	47.20%	['fuzz_eval', 'fuzz_compile']
js_parse_unary	129	39	30.23%	['fuzz_eval', 'fuzz_compile']
get_lvalue	121	55	45.45%	['fuzz_eval', 'fuzz_compile']
put_lvalue	109	35	32.11%	['fuzz_eval', 'fuzz_compile']
js_parse_import	125	36	28.79%	['fuzz_eval', 'fuzz_compile']
js_parse_statement_or_decl	626	98	15.65%	['fuzz_eval', 'fuzz_compile']
emit_return	68	17	25.0%	['fuzz_eval', 'fuzz_compile']
resolve_variables	309	137	44.33%	['fuzz_eval', 'fuzz_compile']
resolve_scope_var	425	176	41.41%	['fuzz_eval', 'fuzz_compile']
resolve_labels	776	311	40.07%	['fuzz_eval', 'fuzz_compile']
compute_stack_size	180	96	53.33%	['fuzz_eval', 'fuzz_compile']
ss_check	33	17	51.51%	['fuzz_eval', 'fuzz_compile']
unicode_to_utf8	32	16	50.0%	['fuzz_eval', 'fuzz_compile', 'fuzz_regexp']
js_dtoa_max_len	39	15	38.46%	['fuzz_eval', 'fuzz_compile']
js_dtoa	172	29	16.86%	['fuzz_eval', 'fuzz_compile']
JS_HasProperty	37	20	54.05%	['fuzz_eval', 'fuzz_compile']
JS_GetPropertyValue	69	26	37.68%	['fuzz_eval', 'fuzz_compile']
delete_property	83	35	42.16%	['fuzz_eval', 'fuzz_compile']
JS_ToBoolFree	59	25	42.37%	['fuzz_eval', 'fuzz_compile']
JS_ToPrimitiveFree	69	34	49.27%	['fuzz_eval', 'fuzz_compile']
JS_ToInt64SatFree	38	13	34.21%	['fuzz_eval', 'fuzz_compile']
js_for_in_next	80	27	33.75%	['fuzz_eval', 'fuzz_compile']
js_for_in_prepare_prototype_chain_enum	52	23	44.23%	['fuzz_eval', 'fuzz_compile']
JS_GetIterator	31	12	38.70%	['fuzz_eval', 'fuzz_compile']
JS_IteratorNext2	31	17	54.83%	['fuzz_eval', 'fuzz_compile']
JS_ConcatString	72	19	26.38%	['fuzz_eval', 'fuzz_compile']
js_add_slow	103	22	21.35%	['fuzz_eval', 'fuzz_compile']
js_binary_arith_slow	178	35	19.66%	['fuzz_eval', 'fuzz_compile']
js_unary_arith_slow	134	27	20.14%	['fuzz_eval', 'fuzz_compile']
js_binary_logic_slow	153	28	18.30%	['fuzz_eval', 'fuzz_compile']
JS_CallConstructorInternal	40	15	37.5%	['fuzz_eval', 'fuzz_compile']
JS_ToObject	46	16	34.78%	['fuzz_eval', 'fuzz_compile']
js_compile_regexp	69	37	53.62%	['fuzz_eval', 'fuzz_compile']
js_regexp_constructor	78	27	34.61%	['fuzz_eval', 'fuzz_compile']
js_regexp_exec	196	101	51.53%	['fuzz_eval']
define_var	112	43	38.39%	['fuzz_eval']
js_parse_regexp	100	44	44.0%	['fuzz_eval']
js_parse_destructuring_element	403	84	20.84%	['fuzz_eval']
js_parse_property_name	106	19	17.92%	['fuzz_eval']
js_define_var	34	14	41.17%	['fuzz_eval']
js_array_join	50	27	54.0%	['fuzz_eval']
js_function_toString	38	10	26.31%	['fuzz_eval']

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

Directories in report

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