High level conclusions

Fuzzers reach 49.15% of cyclomatic complexity.

Fuzzers reach 53.88% of all functions.

Fuzzer fuzz_regexp is blocked:

The runtime code coverage of fuzz_regexp covers 26.61% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Reachability and coverage overview

Functions statically reachable by fuzzers

1012 / 1878

Cyclomatic complexity statically reachable by fuzzers

7812 / 15894

Runtime code coverage of functions

870 / 1878

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	541	89.1%
gold	[1:9]	32	5.27%
yellow	[10:29]	2	0.32%
greenyellow	[30:49]	4	0.65%
lawngreen	50+	28	4.61%
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
370	36	re_parse_alternative	call site: 00036	re_parse_disjunction
61	544	lre_exec_backtrack	call site: 00544	lre_canonicalize
38	440	re_parse_term	call site: 00440	re_emit_goto
13	421	re_emit_char	call site: 00421	re_emit_range
12	408	re_emit_op_u16	call site: 00408	rqsort
12	518	lre_exec_backtrack	call site: 00518	is_line_terminator
10	532	lre_exec_backtrack	call site: 00532	lre_is_space
5	486	compute_register_count	call site: 00486	re_parse_error
4	435	re_parse_term	call site: 00435	re_emit_string_list
4	512	lre_exec_backtrack	call site: 00512	stack_realloc
2	32	re_parse_disjunction	call site: 00032	re_parse_error
2	492	lre_compile	call site: 00492	dbuf_put

Runtime coverage analysis

Covered functions

37

Functions that are reachable but not covered

102

Reachable functions

139

Percentage of reachable functions covered

26.62%

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_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	3298	57.3%
gold	[1:9]	58	1.00%
yellow	[10:29]	98	1.70%
greenyellow	[30:49]	143	2.48%
lawngreen	50+	2151	37.4%
All colors	5748	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
182	4929	js_std_add_helpers	call site: 04929	js_print
173	4033	re_string_list_free	call site: 04033	parse_class_string_disjunction
96	2930	js_operator_in	call site: 02930	js_operator_private_in
77	3148	js_async_function_call	call site: 03148	JS_NewCFunctionData
76	4770	ident_realloc	call site: 04770	json_parse_value
75	4513	JS_AddIntrinsicTypedArrays	call site: 04513	js_typed_array_constructor_obj
70	3711	js_date_constructor	call site: 03711	js_Date_parse
69	2142	js_for_of_start	call site: 02142	JS_GetPropertyInternal
61	2367	JS_CallInternal	call site: 02367	JS_GetPropertyValue
56	3091	js_async_function_resume	call site: 03091	js_promise_resolve
46	4212	get_class_atom	call site: 04212	re_parse_class_set_operand
45	2530	JS_ConcatString2	call site: 02530	js_new_string_rope

Runtime coverage analysis

Covered functions

887

Functions that are reachable but not covered

389

Reachable functions

1040

Percentage of reachable functions covered

62.6%

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	776
./list.h	6
./cutils.h	29
./quickjs.h	22
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	3114	58.8%
gold	[1:9]	89	1.68%
yellow	[10:29]	85	1.60%
greenyellow	[30:49]	60	1.13%
lawngreen	50+	1944	36.7%
All colors	5292	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
225	4033	re_string_list_free	call site: 04033	re_parse_class_set_operand
182	4929	js_std_add_helpers	call site: 04929	js_print
96	2930	js_operator_in	call site: 02930	js_operator_private_in
77	3148	js_async_function_call	call site: 03148	JS_NewCFunctionData
76	4770	ident_realloc	call site: 04770	json_parse_value
75	4513	JS_AddIntrinsicTypedArrays	call site: 04513	js_typed_array_constructor_obj
70	3711	js_date_constructor	call site: 03711	js_Date_parse
69	2142	js_for_of_start	call site: 02142	JS_GetPropertyInternal
61	2367	JS_CallInternal	call site: 02367	JS_GetPropertyValue
56	3091	js_async_function_resume	call site: 03091	js_promise_resolve
46	3967	lre_is_id_continue	call site: 03967	re_parse_disjunction
45	2530	JS_ConcatString2	call site: 02530	js_new_string_rope

Runtime coverage analysis

Covered functions

888

Functions that are reachable but not covered

371

Reachable functions

977

Percentage of reachable functions covered

62.03%

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	714
./list.h	6
./cutils.h	28
./quickjs.h	22
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']	95	0	341	58	20	821	0	7529	2753
js_regexp_Symbol_replace	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	69	0	767	125	50	655	0	5246	310
js_json_to_str	/src/quickjs/quickjs.c	5	['N/A', 'N/A', 'size_t', 'size_t', 'N/A']	74	0	781	139	54	644	3	4943	252
js_string_normalize	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	68	0	155	31	13	637	0	4798	127
js_typed_array_indexOf	/src/quickjs/quickjs.c	6	['N/A', 'size_t', 'size_t', 'int', 'N/A', 'int']	70	0	931	227	93	622	0	4756	115
js_os_exec	/src/quickjs/quickjs-libc.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	70	0	749	163	61	633	0	4757	111
js_set_difference	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	71	0	257	39	17	629	0	4755	90

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

Functions statically reachable by fuzzers

1268 / 1878

Cyclomatic complexity statically reachable by fuzzers

11492 / 15894

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=['re_parse_alternative', 'lre_exec_backtrack', 're_parse_term', 're_emit_char', 're_emit_op_u16', 'compute_register_count']

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_std_add_helpers', 're_string_list_free', 'js_operator_in', 'js_async_function_call', 'ident_realloc', 'JS_AddIntrinsicTypedArrays', 'js_date_constructor', 'js_for_of_start', 'JS_CallInternal', 'js_async_function_resume']

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=['re_string_list_free', 'js_std_add_helpers', 'js_operator_in', 'js_async_function_call', 'ident_realloc', 'JS_AddIntrinsicTypedArrays', 'js_date_constructor', 'js_for_of_start', 'JS_CallInternal', 'js_async_function_resume']

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
re_parse_term	471	75	15.92%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
compute_register_count	60	19	31.66%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
lre_exec_backtrack	493	126	25.55%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
unicode_to_utf8	32	16	50.0%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
exchange_func	33	9	27.27%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
u64toa_radix	31	4	12.90%	['fuzz_compile', 'fuzz_eval']
js_dtoa_max_len	39	15	38.46%	['fuzz_compile', 'fuzz_eval']
js_dtoa	172	91	52.90%	['fuzz_compile', 'fuzz_eval']
lre_parse_escape	108	15	13.88%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
re_parse_nested_class	142	20	14.08%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
re_emit_string_list	64	9	14.06%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
re_emit_range	31	10	32.25%	['fuzz_compile', 'fuzz_eval', 'fuzz_regexp']
js_load_file	41	8	19.51%	['fuzz_compile', 'fuzz_eval']
js_module_loader	43	14	32.55%	['fuzz_compile', 'fuzz_eval']
js_os_poll	98	14	14.28%	['fuzz_compile', 'fuzz_eval']
JS_GetPropertyInternal	138	68	49.27%	['fuzz_compile', 'fuzz_eval']
JS_SetPropertyInternal	247	61	24.69%	['fuzz_compile', 'fuzz_eval']
JS_DefineProperty	262	89	33.96%	['fuzz_compile', 'fuzz_eval']
JS_GetOwnPropertyNamesInternal	180	96	53.33%	['fuzz_compile', 'fuzz_eval']
JS_GetOwnPropertyInternal	70	31	44.28%	['fuzz_compile', 'fuzz_eval']
JS_GetPropertyValue	69	26	37.68%	['fuzz_compile', 'fuzz_eval']
set_array_length	70	13	18.57%	['fuzz_compile', 'fuzz_eval']
JS_ToBoolFree	59	32	54.23%	['fuzz_compile', 'fuzz_eval']
JS_ToInt32SatFree	41	22	53.65%	['fuzz_compile', 'fuzz_eval']
JS_ToInt64SatFree	38	13	34.21%	['fuzz_compile', 'fuzz_eval']
JS_ToArrayLengthFree	54	17	31.48%	['fuzz_compile', 'fuzz_eval']
js_strict_eq2	118	18	15.25%	['fuzz_compile', 'fuzz_eval']
js_call_c_function	112	55	49.10%	['fuzz_compile', 'fuzz_eval']
JS_CallInternal	2600	1091	41.96%	['fuzz_compile', 'fuzz_eval']
js_dynamic_import	88	30	34.09%	['fuzz_compile', 'fuzz_eval']
js_for_in_prepare_prototype_chain_enum	52	23	44.23%	['fuzz_compile', 'fuzz_eval']
JS_GetIterator	31	12	38.70%	['fuzz_compile', 'fuzz_eval']
js_append_enumerate	64	17	26.56%	['fuzz_compile', 'fuzz_eval']
JS_ConcatString	72	25	34.72%	['fuzz_compile', 'fuzz_eval']
js_bigint_pow	74	37	50.0%	['fuzz_compile', 'fuzz_eval']
js_bigint_float64_cmp	42	20	47.61%	['fuzz_compile', 'fuzz_eval']
js_eq_slow	113	36	31.85%	['fuzz_compile', 'fuzz_eval']
JS_CallConstructorInternal	40	15	37.5%	['fuzz_compile', 'fuzz_eval']
JS_LoadModuleInternal	36	15	41.66%	['fuzz_compile', 'fuzz_eval']
js_default_module_normalize_name	46	8	17.39%	['fuzz_compile', 'fuzz_eval']
js_inner_module_linking	130	69	53.07%	['fuzz_compile', 'fuzz_eval']
JS_WriteObjectRec	134	57	42.53%	['fuzz_compile', 'fuzz_eval']
JS_WriteModule	44	17	38.63%	['fuzz_compile', 'fuzz_eval']
JS_ReadObjectRec	107	43	40.18%	['fuzz_compile', 'fuzz_eval']
JS_ReadModule	103	25	24.27%	['fuzz_compile', 'fuzz_eval']
JS_ToObject	46	24	52.17%	['fuzz_compile', 'fuzz_eval']
js_string_define_own_property	32	11	34.37%	['fuzz_compile', 'fuzz_eval']
js_regexp_exec	196	101	51.53%	['fuzz_compile', 'fuzz_eval']
js_string_GetSubstitution	103	26	25.24%	['fuzz_compile', 'fuzz_eval']
js_promise_resolve_function_call	41	19	46.34%	['fuzz_compile', 'fuzz_eval']
fulfill_or_reject_promise	32	15	46.87%	['fuzz_compile', 'fuzz_eval']
js_async_function_resume	45	20	44.44%	['fuzz_compile', 'fuzz_eval']
js_date_constructor	56	17	30.35%	['fuzz_compile', 'fuzz_eval']
js_parse_directives	77	22	28.57%	['fuzz_compile', 'fuzz_eval']
js_parse_function_decl2	463	223	48.16%	['fuzz_compile', 'fuzz_eval']
js_parse_destructuring_element	403	85	21.09%	['fuzz_compile', 'fuzz_eval']
js_parse_postfix_expr	579	318	54.92%	['fuzz_compile', 'fuzz_eval']
js_parse_class	435	184	42.29%	['fuzz_compile', 'fuzz_eval']
js_parse_object_literal	106	36	33.96%	['fuzz_compile', 'fuzz_eval']
js_parse_array_literal	84	38	45.23%	['fuzz_compile', 'fuzz_eval']
js_parse_delete	86	20	23.25%	['fuzz_compile', 'fuzz_eval']
js_parse_property_name	106	39	36.79%	['fuzz_compile', 'fuzz_eval']
put_lvalue	109	47	43.11%	['fuzz_compile', 'fuzz_eval']
js_parse_import	125	36	28.79%	['fuzz_compile', 'fuzz_eval']
js_parse_statement_or_decl	626	292	46.64%	['fuzz_compile', 'fuzz_eval']
js_parse_for_in_of	182	100	54.94%	['fuzz_compile', 'fuzz_eval']
is_let	36	6	16.66%	['fuzz_compile', 'fuzz_eval']
emit_return	68	27	39.70%	['fuzz_compile', 'fuzz_eval']
resolve_scope_var	425	213	50.11%	['fuzz_compile', 'fuzz_eval']
resolve_pseudo_var	31	17	54.83%	['fuzz_compile', 'fuzz_eval']
ss_check	33	17	51.51%	['fuzz_compile', 'fuzz_eval']
js_array_join	50	23	46.0%	['fuzz_compile', 'fuzz_eval']
js_string_replace	99	23	23.23%	['fuzz_compile', '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/libunicode.c	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/fuzz/fuzz_common.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/dtoa.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/./list.h	['fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/fuzz/fuzz_eval.c	['fuzz_eval']	['fuzz_eval']
/src/quickjs/libregexp.c	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
/src/quickjs/./cutils.h	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/fuzz/fuzz_regexp.c	['fuzz_regexp']	['fuzz_regexp']
/src/quickjs/./quickjs.h	['fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/./libunicode.h	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/fuzz/fuzz_compile.c	['fuzz_compile']	['fuzz_compile']
/src/quickjs/quickjs-libc.c	['fuzz_compile', 'fuzz_eval']	['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']

Directories in report

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