High level conclusions

Fuzzers reach 96.20% of cyclomatic complexity.

Fuzzers reach 92.23% of all functions.

Fuzzers reach 96.11% code coverage.

Reachability and coverage overview

Functions statically reachable by fuzzers

95 / 103

Cyclomatic complexity statically reachable by fuzzers

709 / 737

Runtime code coverage of functions

99 / 103

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: fuzztest_proto3_static

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	65	25.3%
gold	[1:9]	0	0.0%
yellow	[10:29]	1	0.39%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	190	74.2%
All colors	256	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
14	121	validate_static	call site: 00121	validate_pointer
7	62	pb_field_iter_find_extension	call site: 00062	decode_extension
6	159	pb_encode	call site: 00159	encode_extension_field
5	21	pb_message_set_to_defaults	call site: 00021	pb_message_set_to_defaults
5	79	pb_close_string_substream	call site: 00079	read_raw_value
5	102	decode_static_field	call site: 00102	pb_message_set_to_defaults
3	95	decode_static_field	call site: 00095	pb_message_set_to_defaults
2	14	pb_decode_inner	call site: 00014	pb_decode_tag
2	76	pb_skip_field	call site: 00076	pb_make_string_substream
2	136	validate_message	call site: 00136	fprintf
2	193	pb_encode_tag_for_field	call site: 00193	encode_basic_field
2	221	do_roundtrip	call site: 00221	fprintf

Runtime coverage analysis

Covered functions

78

Functions that are reachable but not covered

17

Reachable functions

92

Percentage of reachable functions covered

81.52%

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
tests/build/fuzztest/fuzztest.c	6
tests/build/common/malloc_wrappers.c	5
pb_decode.c	35
pb_common.c	10
tests/build/fuzztest/validation.c	3
pb_encode.c	27
tests/build/fuzztest/flakystream.c	1

Fuzzer: fuzztest_io_errors

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	11	5.04%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	207	94.9%
All colors	218	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
2	177	validate_message	call site: 00177	fprintf
2	194	do_decode	call site: 00194	fprintf
2	209	pb_decode	call site: 00209	fprintf
2	215	do_callback_decode	call site: 00215	get_alloc_count
1	24	pb_field_set_to_default	call site: 00024	pb_field_iter_begin
1	76	realloc_with_check	call site: 00076	free_with_check
1	115	decode_field	call site: 00115	pb_skip_field

Runtime coverage analysis

Covered functions

71

Functions that are reachable but not covered

6

Reachable functions

72

Percentage of reachable functions covered

91.67%

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
tests/build/fuzztest/fuzztest.c	5
tests/build/common/malloc_wrappers.c	9
tests/build/fuzztest/flakystream.c	1
pb_decode.c	39
pb_common.c	9
tests/build/fuzztest/validation.c	3

Fuzzer: fuzztest_proto3_pointer

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	70	23.9%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	222	76.0%
All colors	292	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
13	196	pb_encode	call site: 00196	encode_extension_field
8	132	pb_dec_submessage	call site: 00132	decode_basic_field
8	153	validate_message	call site: 00153	__assert_fail
7	122	pb_skip_field	call site: 00122	pb_make_string_substream
5	21	pb_message_set_to_defaults	call site: 00021	pb_message_set_to_defaults
5	142	decode_static_field	call site: 00142	pb_message_set_to_defaults
4	91	pb_field_iter_find_extension	call site: 00091	decode_extension
2	14	pb_decode_inner	call site: 00014	pb_decode_tag
2	32	pb_release_union_field	call site: 00032	pb_release_single_field
2	113	decode_pointer_field	call site: 00113	decode_callback_field
2	176	validate_message	call site: 00176	fprintf
2	258	do_roundtrip	call site: 00258	fprintf

Runtime coverage analysis

Covered functions

85

Functions that are reachable but not covered

16

Reachable functions

98

Percentage of reachable functions covered

83.67%

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
tests/build/fuzztest/fuzztest.c	6
tests/build/common/malloc_wrappers.c	6
pb_decode.c	39
pb_common.c	10
tests/build/fuzztest/validation.c	3
pb_encode.c	27
tests/build/fuzztest/flakystream.c	1

Fuzzer: fuzztest_proto2_pointer

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	51	17.4%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	241	82.5%
All colors	292	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
8	153	validate_message	call site: 00153	__assert_fail
7	122	pb_skip_field	call site: 00122	pb_make_string_substream
7	133	decode_static_field	call site: 00133	decode_basic_field
6	203	encode_field	call site: 00203	pb_check_proto3_default_value
5	142	decode_static_field	call site: 00142	pb_message_set_to_defaults
2	14	pb_decode_inner	call site: 00014	pb_decode_tag
2	113	decode_pointer_field	call site: 00113	decode_callback_field
2	176	validate_message	call site: 00176	fprintf
2	258	do_roundtrip	call site: 00258	fprintf
2	289	do_stream_decode	call site: 00289	get_alloc_count
1	22	pb_field_set_to_default	call site: 00022	pb_field_iter_begin
1	25	pb_field_set_to_default	call site: 00025	decode_field

Runtime coverage analysis

Covered functions

91

Functions that are reachable but not covered

10

Reachable functions

98

Percentage of reachable functions covered

89.8%

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
tests/build/fuzztest/fuzztest.c	6
tests/build/common/malloc_wrappers.c	6
pb_decode.c	39
pb_common.c	10
tests/build/fuzztest/validation.c	3
pb_encode.c	27
tests/build/fuzztest/flakystream.c	1

Fuzzer: fuzztest_proto2_static

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	38	14.1%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	230	85.8%
All colors	268	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
14	121	validate_static	call site: 00121	validate_pointer
6	166	encode_field	call site: 00166	pb_check_proto3_default_value
3	104	pb_field_set_to_default	call site: 00104	pb_decode_inner
2	136	validate_message	call site: 00136	fprintf
2	193	pb_encode_tag_for_field	call site: 00193	encode_basic_field
2	221	do_roundtrip	call site: 00221	fprintf
2	265	do_callback_decode	call site: 00265	get_alloc_count
1	22	pb_field_set_to_default	call site: 00022	pb_field_iter_begin
1	66	default_extension_decoder	call site: 00066	decode_pointer_field
1	68	decode_field	call site: 00068	pb_skip_field
1	184	encode_array	call site: 00184	pb_write
1	191	encode_array	call site: 00191	pb_encode_tag_for_field

Runtime coverage analysis

Covered functions

89

Functions that are reachable but not covered

10

Reachable functions

93

Percentage of reachable functions covered

89.25%

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
tests/build/fuzztest/fuzztest.c	7
tests/build/common/malloc_wrappers.c	5
pb_decode.c	35
pb_common.c	10
tests/build/fuzztest/validation.c	3
pb_encode.c	27
tests/build/fuzztest/flakystream.c	1

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

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

Functions statically reachable by fuzzers

95 / 103

Cyclomatic complexity statically reachable by fuzzers

709 / 737

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.

tests/build/fuzztest/fuzztest.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=['validate_static', 'pb_field_iter_find_extension', 'pb_encode', 'pb_message_set_to_defaults', 'pb_close_string_substream', 'decode_static_field', 'pb_decode_inner', 'pb_skip_field', 'validate_message']

tests/build/fuzztest/fuzztest.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=['validate_message', 'do_decode', 'pb_decode', 'do_callback_decode', 'pb_field_set_to_default', 'realloc_with_check', 'decode_field']

tests/build/fuzztest/fuzztest.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=['pb_encode', 'pb_dec_submessage', 'validate_message', 'pb_skip_field', 'pb_message_set_to_defaults', 'decode_static_field', 'pb_field_iter_find_extension', 'pb_decode_inner', 'pb_release_union_field', 'decode_pointer_field']

tests/build/fuzztest/fuzztest.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=['validate_message', 'pb_skip_field', 'decode_static_field', 'encode_field', 'pb_decode_inner', 'decode_pointer_field', 'do_roundtrip', 'do_stream_decode']

tests/build/fuzztest/fuzztest.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=['validate_static', 'encode_field', 'pb_field_set_to_default', 'validate_message', 'pb_encode_tag_for_field', 'do_roundtrip', 'do_callback_decode', 'default_extension_decoder', 'decode_field']

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

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/nanopb/tests/build/fuzztest/flakystream.c	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']
/src/nanopb/tests/build/fuzztest/validation.c	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']
/src/nanopb/pb_common.c	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']
/src/nanopb/pb_decode.c	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']
/src/nanopb/tests/build/common/malloc_wrappers.c	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']
/src/nanopb/tests/build/fuzztest/fuzztest.c	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_io_errors', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']
/src/nanopb/pb_encode.c	['fuzztest_proto3_static', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']	['fuzztest_proto3_static', 'fuzztest_proto3_pointer', 'fuzztest_proto2_pointer', 'fuzztest_proto2_static']

Directories in report

Directory
/src/nanopb/
/src/nanopb/tests/build/common/
/src/nanopb/tests/build/fuzztest/