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

717 / 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	444	73.1%
gold	[1:9]	90	14.8%
yellow	[10:29]	7	1.15%
greenyellow	[30:49]	7	1.15%
lawngreen	50+	59	9.71%
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
169	150	re_parse_term	call site: 00150	re_parse_char_class
50	356	get_class_atom	call site: 00356	re_parse_class_set_operand
41	75	re_parse_term	call site: 00075	re_parse_group_name
29	575	lre_exec_backtrack	call site: 00575	lre_canonicalize
22	123	re_parse_term	call site: 00123	re_has_named_captures
19	335	lre_canonicalize	call site: 00335	parse_class_string_disjunction
14	320	lre_case_folding_entry	call site: 00320	cr_sort_and_remove_overlap
13	421	re_emit_char	call site: 00421	re_emit_range
12	408	re_emit_op_u16	call site: 00408	rqsort
10	532	lre_exec_backtrack	call site: 00532	lre_is_space
8	40	re_parse_term	call site: 00040	re_parse_disjunction
8	518	lre_exec_backtrack	call site: 00518	is_line_terminator

Runtime coverage analysis

Covered functions

55

Functions that are reachable but not covered

84

Reachable functions

139

Percentage of reachable functions covered

39.57%

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_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]	1023	17.4%
yellow	[10:29]	195	3.32%
greenyellow	[30:49]	51	0.86%
lawngreen	50+	362	6.16%
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

595

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	3835	70.8%
gold	[1:9]	319	5.88%
yellow	[10:29]	677	12.5%
greenyellow	[30:49]	93	1.71%
lawngreen	50+	492	9.08%
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
276	2864	JS_CallInternal	call site: 02864	js_unary_arith_slow
183	5048	js_std_add_helpers	call site: 05048	js_print
139	2390	JS_ToStringFree	call site: 02390	string_buffer_init2
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
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
72	4000	dbuf_put_u32	call site: 04000	re_parse_disjunction
60	2619	JS_ConcatString	call site: 02619	JS_ConcatString2
52	2534	JS_DefinePropertyValueValue	call site: 02534	js_append_enumerate

Runtime coverage analysis

Covered functions

635

Functions that are reachable but not covered

525

Reachable functions

989

Percentage of reachable functions covered

46.92%

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=['re_parse_term', 'get_class_atom', 'lre_exec_backtrack', 'lre_canonicalize', 'lre_case_folding_entry', 're_emit_char', 're_emit_op_u16']

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_CallInternal', 'js_std_add_helpers', 'JS_ToStringFree', 'js_async_function_resume', 'js_for_in_prepare_prototype_chain_enum', 'JS_AddIntrinsicDate', 'ident_realloc', 'js_binary_arith_slow', '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
re_parse_term	471	222	47.13%	['fuzz_eval', 'fuzz_regexp', 'fuzz_compile']
get_class_atom	165	48	29.09%	['fuzz_eval', 'fuzz_regexp', 'fuzz_compile']
lre_case_conv_entry	88	24	27.27%	['fuzz_eval', 'fuzz_regexp', 'fuzz_compile']
exchange_func	33	13	39.39%	['fuzz_eval', 'fuzz_regexp', 'fuzz_compile']
js_os_poll	97	12	12.37%	['fuzz_eval', 'fuzz_compile']
JS_ExecutePendingJob	31	10	32.25%	['fuzz_eval', 'fuzz_compile']
JS_GetPropertyInternal	138	61	44.20%	['fuzz_eval', 'fuzz_compile']
JS_SetPropertyInternal	247	51	20.64%	['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']
add_property	50	27	54.0%	['fuzz_eval', 'fuzz_compile']
JS_ToInt32Free	45	16	35.55%	['fuzz_eval', 'fuzz_compile']
JS_ToStringInternal	54	21	38.88%	['fuzz_eval', 'fuzz_compile']
js_call_c_function	112	43	38.39%	['fuzz_eval', 'fuzz_compile']
JS_CallInternal	2787	570	20.45%	['fuzz_eval', 'fuzz_compile']
simple_next_token	81	44	54.32%	['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	66	50.76%	['fuzz_eval', 'fuzz_compile']
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_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	184	44.12%	['fuzz_eval', 'fuzz_compile']
js_parse_string	120	56	46.66%	['fuzz_eval', 'fuzz_compile']
js_parse_postfix_expr	579	162	27.97%	['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	72	44.72%	['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	627	99	15.78%	['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	82	45.55%	['fuzz_eval', 'fuzz_compile']
ss_check	33	17	51.51%	['fuzz_eval', 'fuzz_compile']
unicode_to_utf8	32	16	50.0%	['fuzz_eval', 'fuzz_regexp', 'fuzz_compile']
js_dtoa_max_len	39	15	38.46%	['fuzz_eval', 'fuzz_compile']
js_dtoa	172	29	16.86%	['fuzz_eval', 'fuzz_compile']
lre_parse_escape	108	21	19.44%	['fuzz_eval', 'fuzz_regexp', '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	10	16.94%	['fuzz_eval', 'fuzz_compile']
JS_ToPrimitiveFree	69	33	47.82%	['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_ConcatString	72	16	22.22%	['fuzz_eval', 'fuzz_compile']
js_add_slow	103	15	14.56%	['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_ToObject	46	16	34.78%	['fuzz_eval', 'fuzz_compile']
define_var	112	43	38.39%	['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_parse_for_in_of	183	100	54.64%	['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/dtoa.c	['fuzz_compile', 'fuzz_eval']	['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/fuzz/fuzz_common.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/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/./list.h	['fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/fuzz/fuzz_eval.c	['fuzz_eval']	['fuzz_eval']
/src/quickjs/quickjs.c	['fuzz_compile', 'fuzz_eval']	['fuzz_compile', 'fuzz_eval']
/src/quickjs/./quickjs.h	['fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/fuzz/fuzz_regexp.c	['fuzz_regexp']	['fuzz_regexp']
/src/quickjs/cutils.c	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']
/src/quickjs/./libunicode.h	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	[]
/src/quickjs/./cutils.h	['fuzz_regexp', 'fuzz_compile', 'fuzz_eval']	[]

Directories in report

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