High level conclusions

Fuzzers reach 49.51% of cyclomatic complexity.

Fuzzers reach 54.12% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

1023 / 1890

Cyclomatic complexity statically reachable by fuzzers

7957 / 16070

Runtime code coverage of functions

759 / 1890

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	358	58.9%
gold	[1:9]	50	8.23%
yellow	[10:29]	37	6.09%
greenyellow	[30:49]	7	1.15%
lawngreen	50+	155	25.5%
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	198	cr_op	call site: 00198	unicode_prop
31	573	lre_exec_backtrack	call site: 00573	lre_canonicalize
18	171	re_string_list_free	call site: 00171	parse_unicode_property
17	384	re_parse_nested_class	call site: 00384	re_parse_class_set_operand
14	93	lre_js_is_ident_first	call site: 00093	lre_js_is_ident_next
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	81	lre_parse_escape	call site: 00081	unicode_from_utf8
10	532	lre_exec_backtrack	call site: 00532	lre_is_space
8	40	re_parse_term	call site: 00040	re_parse_disjunction

Runtime coverage analysis

Covered functions

89

Functions that are reachable but not covered

52

Reachable functions

139

Percentage of reachable functions covered

62.59%

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	4242	72.2%
gold	[1:9]	852	14.5%
yellow	[10:29]	279	4.75%
greenyellow	[30:49]	74	1.26%
lawngreen	50+	426	7.25%
All colors	5873	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
554	2588	JS_DefinePropertyValueUint32	call site: 02588	JS_IteratorNext
405	4082	lre_js_is_ident_next	call site: 04082	js_regexp_set_internal
194	2335	JS_CallInternal	call site: 02335	JS_NewSymbolFromAtom
183	5048	js_std_add_helpers	call site: 05048	js_print
158	2161	JS_CallInternal	call site: 02161	JS_ThrowInternalError
135	3207	js_async_function_resume	call site: 03207	js_promise_resolve
104	4878	string_buffer_putc_slow	call site: 04878	json_parse_value
99	5719	JS_ReadModule	call site: 05719	JS_ReadObjectRec
75	2085	JS_CallInternal	call site: 02085	JS_ThrowReferenceErrorUninitialized2
75	4631	JS_AddIntrinsicTypedArrays	call site: 04631	js_typed_array_constructor_obj
74	1708	JS_ToInt32	call site: 01708	JS_ToNumberFree
72	4000	dbuf_put_u32	call site: 04000	re_parse_disjunction

Runtime coverage analysis

Covered functions

598

Functions that are reachable but not covered

591

Reachable functions

1052

Percentage of reachable functions covered

43.82%

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	784
./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	34

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	3767	69.5%
gold	[1:9]	852	15.7%
yellow	[10:29]	288	5.31%
greenyellow	[30:49]	41	0.75%
lawngreen	50+	468	8.64%
All colors	5416	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
403	4084	lre_is_id_continue	call site: 04084	js_regexp_set_internal
183	5048	js_std_add_helpers	call site: 05048	js_print
135	3207	js_async_function_resume	call site: 03207	js_promise_resolve
119	2193	js_for_in_prepare_prototype_chain_enum	call site: 02193	JS_GetOwnPropertyNamesInternal
107	3033	JS_CallInternal	call site: 03033	js_operator_in
104	3827	JS_AddIntrinsicDate	call site: 03827	js_Date_parse
94	4888	ident_realloc	call site: 04888	json_parse_value
81	2750	js_binary_arith_slow	call site: 02750	js_bigint_add
74	2390	JS_ToStringFree	call site: 02390	string_buffer_init2
72	4000	dbuf_put_u32	call site: 04000	re_parse_disjunction
60	2619	JS_ConcatString	call site: 02619	JS_ConcatString2
57	2886	js_not_slow	call site: 02886	js_binary_logic_slow

Runtime coverage analysis

Covered functions

650

Functions that are reachable but not covered

509

Reachable functions

989

Percentage of reachable functions covered

48.53%

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	722
./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	34

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	334	57	20	829	0	7661	2755
js_regexp_Symbol_replace	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	70	0	712	120	49	663	0	5375	309
js_json_to_str	/src/quickjs/quickjs.c	5	['N/A', 'N/A', 'size_t', 'size_t', 'N/A']	75	0	775	140	54	652	3	5073	252
js_string_normalize	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	69	0	150	31	13	645	0	4928	127
js_typed_array_indexOf	/src/quickjs/quickjs.c	6	['N/A', 'size_t', 'size_t', 'int', 'N/A', 'int']	71	0	930	227	93	630	0	4886	115
js_os_exec	/src/quickjs/quickjs-libc.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	71	0	745	163	61	641	0	4887	111
js_set_difference	/src/quickjs/quickjs.c	5	['N/A', 'size_t', 'size_t', 'int', 'N/A']	72	0	248	39	17	637	0	4885	90

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

Functions statically reachable by fuzzers

1279 / 1890

Cyclomatic complexity statically reachable by fuzzers

11638 / 16070

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', 'lre_exec_backtrack', 're_string_list_free', 're_parse_nested_class', 'lre_js_is_ident_first', 'lre_canonicalize', 'cr_op1', 're_emit_char', 'lre_parse_escape']

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', 'js_async_function_resume', 'string_buffer_putc_slow', 'JS_ReadModule', '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_std_add_helpers', 'js_async_function_resume', 'js_for_in_prepare_prototype_chain_enum', 'JS_CallInternal', 'JS_AddIntrinsicDate', 'ident_realloc', 'js_binary_arith_slow', 'JS_ToStringFree', 'dbuf_put_u32']

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_regexp', 'fuzz_compile', 'fuzz_eval']
lre_parse_escape	108	39	36.11%	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
re_parse_nested_class	142	57	40.14%	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
re_emit_string_list	64	9	14.06%	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
js_os_poll	97	12	12.37%	['fuzz_compile', 'fuzz_eval']
JS_ExecutePendingJob	31	10	32.25%	['fuzz_compile', 'fuzz_eval']
JS_GetPropertyInternal	138	49	35.50%	['fuzz_compile', 'fuzz_eval']
JS_SetPropertyInternal	247	51	20.64%	['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	30	42.85%	['fuzz_compile', 'fuzz_eval']
add_property	50	27	54.0%	['fuzz_compile', 'fuzz_eval']
JS_ToStringInternal	54	21	38.88%	['fuzz_compile', 'fuzz_eval']
js_call_c_function	112	46	41.07%	['fuzz_compile', 'fuzz_eval']
JS_CallInternal	2787	625	22.42%	['fuzz_compile', 'fuzz_eval']
simple_next_token	81	37	45.67%	['fuzz_compile', 'fuzz_eval']
js_host_resolve_imported_module	39	17	43.58%	['fuzz_compile', 'fuzz_eval']
js_default_module_normalize_name	46	8	17.39%	['fuzz_compile', 'fuzz_eval']
js_inner_module_linking	130	66	50.76%	['fuzz_compile', 'fuzz_eval']
JS_WriteObjectRec	137	25	18.24%	['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_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_parse_isostring	54	12	22.22%	['fuzz_compile', 'fuzz_eval']
js_date_parse_otherstring	140	42	30.0%	['fuzz_compile', 'fuzz_eval']
push_scope	32	13	40.62%	['fuzz_compile', 'fuzz_eval']
next_token	417	213	51.07%	['fuzz_compile', 'fuzz_eval']
js_parse_string	120	52	43.33%	['fuzz_compile', 'fuzz_eval']
js_parse_function_decl2	463	239	51.61%	['fuzz_compile', 'fuzz_eval']
js_parse_regexp	100	31	31.0%	['fuzz_compile']
js_parse_postfix_expr	579	212	36.61%	['fuzz_compile', 'fuzz_eval']
js_parse_array_literal	84	32	38.09%	['fuzz_compile']
js_parse_assign_expr2	236	46	19.49%	['fuzz_compile', 'fuzz_eval']
js_parse_logical_and_or	35	12	34.28%	['fuzz_compile', 'fuzz_eval']
js_parse_expr_binary	161	80	49.68%	['fuzz_compile', 'fuzz_eval']
js_parse_unary	129	51	39.53%	['fuzz_compile', 'fuzz_eval']
get_lvalue	121	58	47.93%	['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	627	149	23.76%	['fuzz_compile', 'fuzz_eval']
emit_return	68	17	25.0%	['fuzz_compile', 'fuzz_eval']
resolve_variables	309	141	45.63%	['fuzz_compile', 'fuzz_eval']
resolve_scope_var	425	176	41.41%	['fuzz_compile', 'fuzz_eval']
resolve_labels	776	318	40.97%	['fuzz_compile', 'fuzz_eval']
compute_stack_size	180	82	45.55%	['fuzz_compile', 'fuzz_eval']
ss_check	33	17	51.51%	['fuzz_compile', 'fuzz_eval']
unicode_to_utf8	32	16	50.0%	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
js_dtoa_max_len	39	15	38.46%	['fuzz_compile', 'fuzz_eval']
js_dtoa	172	29	16.86%	['fuzz_compile', 'fuzz_eval']
JS_HasProperty	37	20	54.05%	['fuzz_compile', 'fuzz_eval']
JS_GetPropertyValue	69	28	40.57%	['fuzz_compile', 'fuzz_eval']
JS_SetPropertyValue	115	23	20.0%	['fuzz_compile', 'fuzz_eval']
delete_property	83	35	42.16%	['fuzz_compile', 'fuzz_eval']
JS_ToBoolFree	59	10	16.94%	['fuzz_compile', 'fuzz_eval']
JS_ToPrimitiveFree	69	33	47.82%	['fuzz_compile', 'fuzz_eval']
JS_ToInt64SatFree	38	13	34.21%	['fuzz_compile', 'fuzz_eval']
JS_CheckDefineGlobalVar	34	15	44.11%	['fuzz_compile', 'fuzz_eval']
js_closure_define_global_var	88	27	30.68%	['fuzz_compile', 'fuzz_eval']
js_for_in_next	80	27	33.75%	['fuzz_compile', 'fuzz_eval']
js_for_in_prepare_prototype_chain_enum	52	23	44.23%	['fuzz_compile', 'fuzz_eval']
JS_ConcatString	72	16	22.22%	['fuzz_compile', 'fuzz_eval']
js_add_slow	103	15	14.56%	['fuzz_compile', 'fuzz_eval']
js_binary_arith_slow	178	32	17.97%	['fuzz_compile', 'fuzz_eval']
JS_CallConstructorInternal	40	15	37.5%	['fuzz_compile', 'fuzz_eval']
define_var	112	54	48.21%	['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	17	50.0%	['fuzz_eval']
js_parse_var	87	25	28.73%	['fuzz_eval']
js_parse_for_in_of	183	99	54.09%	['fuzz_eval']
js_array_join	50	23	46.0%	['fuzz_eval']
js_function_toString	38	10	26.31%	['fuzz_eval']
js_array_buffer_constructor3	61	30	49.18%	['fuzz_compile', 'fuzz_eval']
js_typed_array_constructor	78	20	25.64%	['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/./quickjs.h	['fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/quickjs.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/./list.h	['fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/fuzz/fuzz_common.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/./cutils.h	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/cutils.c	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
/src/quickjs/fuzz/fuzz_regexp.c	['fuzz_regexp']	['fuzz_regexp']
/src/quickjs/./libunicode.h	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/libregexp.c	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
/src/quickjs/fuzz/fuzz_compile.c	['fuzz_compile']	['fuzz_compile']
/src/quickjs/dtoa.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/fuzz/fuzz_eval.c	['fuzz_eval']	['fuzz_eval']
/src/quickjs/libunicode.c	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	['fuzz_regexp', 'fuzz_eval']
/src/quickjs/quickjs-libc.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']

Directories in report

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