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_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	37	13.8%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	231	86.1%
All colors	268	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
44	44	1 : View List ['pb_check_proto3_default_value']	49	469	encode_field	call site: 00165	/src/nanopb/pb_encode.c:431
5	5	1 : View List ['encode_callback_field']	5	5	encode_field	call site: 00167	/src/nanopb/pb_encode.c:457
0	43	2 : View List ['pb_make_string_substream', 'pb_close_string_substream']	0	390	pb_decode_ex	call site: 00010	/src/nanopb/pb_decode.c:1202
0	9	1 : View List ['pb_write']	0	9	pb_encode_submessage	call site: 00217	/src/nanopb/pb_encode.c:744
0	9	1 : View List ['pb_write']	0	9	encode_array	call site: 00184	/src/nanopb/pb_encode.c:177
0	0	None	5	425	encode_field	call site: 00167	/src/nanopb/pb_encode.c:447
0	0	None	2	1296	do_roundtrip	call site: 00150	/src/nanopb/tests/build/fuzztest/fuzztest.c:226
0	0	None	0	810	pb_decode_inner	call site: 00014	/src/nanopb/pb_decode.c:1060
0	0	None	0	740	pb_message_set_to_defaults	call site: 00016	/src/nanopb/pb_decode.c:998
0	0	None	0	740	pb_message_set_to_defaults	call site: 00021	/src/nanopb/pb_decode.c:1004
0	0	None	0	740	pb_message_set_to_defaults	call site: 00021	/src/nanopb/pb_decode.c:1010
0	0	None	0	740	pb_message_set_to_defaults	call site: 00021	/src/nanopb/pb_decode.c:1012

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

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	64	25.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	1	0.39%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	191	74.6%
All colors	256	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
15	15	1 : View List ['pb_field_iter_begin_extension']	15	362	pb_field_set_to_default	call site: 00021	/src/nanopb/pb_decode.c:911
5	5	1 : View List ['encode_callback_field']	5	5	encode_field	call site: 00167	/src/nanopb/pb_encode.c:457
0	359	2 : View List ['pb_message_set_to_defaults', 'pb_field_iter_begin']	0	706	decode_static_field	call site: 00095	/src/nanopb/pb_decode.c:557
0	43	2 : View List ['pb_make_string_substream', 'pb_close_string_substream']	0	390	pb_decode_ex	call site: 00010	/src/nanopb/pb_decode.c:1202
0	9	1 : View List ['pb_write']	0	9	pb_encode_submessage	call site: 00217	/src/nanopb/pb_encode.c:744
0	9	1 : View List ['pb_write']	0	9	encode_array	call site: 00184	/src/nanopb/pb_encode.c:177
0	2	1 : View List ['pb_istream_from_buffer']	0	773	pb_message_set_to_defaults	call site: 00014	/src/nanopb/pb_decode.c:995
0	0	None	347	810	pb_decode_inner	call site: 00014	/src/nanopb/pb_decode.c:1060
0	0	None	347	810	pb_decode_inner	call site: 00014	/src/nanopb/pb_decode.c:1085
0	0	None	347	810	pb_decode_inner	call site: 00014	/src/nanopb/pb_decode.c:1097
0	0	None	347	810	pb_decode_inner	call site: 00014	/src/nanopb/pb_decode.c:1141
0	0	None	210	435	pb_encode	call site: 00159	/src/nanopb/pb_encode.c:519

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	9	4.12%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	209	95.8%
All colors	218	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
0	5	1 : View List ['free_with_check']	0	5	realloc_with_check	call site: 00070	/src/nanopb/tests/build/common/malloc_wrappers.c:115
0	0	None	0	810	pb_decode_inner	call site: 00016	/src/nanopb/pb_decode.c:1060
0	0	None	0	740	pb_message_set_to_defaults	call site: 00018	/src/nanopb/pb_decode.c:998
0	0	None	0	740	pb_message_set_to_defaults	call site: 00023	/src/nanopb/pb_decode.c:1004
0	0	None	0	740	pb_message_set_to_defaults	call site: 00023	/src/nanopb/pb_decode.c:1010
0	0	None	0	740	pb_message_set_to_defaults	call site: 00023	/src/nanopb/pb_decode.c:1012
0	0	None	0	438	do_decode	call site: 00191	/src/nanopb/tests/build/fuzztest/fuzztest.c:81
0	0	None	0	362	pb_field_set_to_default	call site: 00027	/src/nanopb/pb_decode.c:920
0	0	None	0	347	decode_extension	call site: 00093	/src/nanopb/pb_decode.c:891
0	0	None	0	347	default_extension_decoder	call site: 00095	/src/nanopb/pb_decode.c:871
0	0	None	0	347	decode_static_field	call site: 00140	/src/nanopb/pb_decode.c:564
0	0	None	0	63	decode_callback_field	call site: 00115	/src/nanopb/pb_decode.c:775

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_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	50	17.1%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	242	82.8%
All colors	292	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
5	5	1 : View List ['encode_callback_field']	5	5	encode_field	call site: 00204	/src/nanopb/pb_encode.c:457
0	359	2 : View List ['pb_message_set_to_defaults', 'pb_field_iter_begin']	0	706	decode_static_field	call site: 00137	/src/nanopb/pb_decode.c:557
0	43	2 : View List ['pb_make_string_substream', 'pb_close_string_substream']	0	390	pb_decode_ex	call site: 00010	/src/nanopb/pb_decode.c:1202
0	12	1 : View List ['pb_read']	0	12	pb_dec_bytes	call site: 00065	/src/nanopb/pb_decode.c:1548
0	9	1 : View List ['pb_write']	0	9	pb_encode_submessage	call site: 00254	/src/nanopb/pb_encode.c:744
0	9	1 : View List ['pb_write']	0	9	encode_array	call site: 00221	/src/nanopb/pb_encode.c:177
0	5	1 : View List ['free_with_check']	0	5	realloc_with_check	call site: 00068	/src/nanopb/tests/build/common/malloc_wrappers.c:115
0	2	1 : View List ['pb_istream_from_buffer']	0	773	pb_message_set_to_defaults	call site: 00014	/src/nanopb/pb_decode.c:995
0	0	None	10	80	validate_static	call site: 00154	/src/nanopb/tests/build/fuzztest/validation.c:19
0	0	None	6	76	validate_static	call site: 00153	/src/nanopb/tests/build/fuzztest/validation.c:13
0	0	None	6	76	validate_static	call site: 00156	/src/nanopb/tests/build/fuzztest/validation.c:38
0	0	None	6	76	validate_static	call site: 00158	/src/nanopb/tests/build/fuzztest/validation.c:43

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_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	69	23.6%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	1	0.34%
lawngreen	50+	222	76.0%
All colors	292	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
15	64	2 : View List ['pb_field_iter_begin_extension', 'pb_release_single_field']	15	74	pb_release_single_field	call site: 00032	/src/nanopb/pb_decode.c:1278
15	15	1 : View List ['pb_field_iter_begin_extension']	15	362	pb_field_set_to_default	call site: 00021	/src/nanopb/pb_decode.c:911
5	5	1 : View List ['encode_callback_field']	5	5	encode_field	call site: 00204	/src/nanopb/pb_encode.c:457
0	359	2 : View List ['pb_message_set_to_defaults', 'pb_field_iter_begin']	0	706	decode_static_field	call site: 00137	/src/nanopb/pb_decode.c:557
0	359	2 : View List ['pb_message_set_to_defaults', 'pb_field_iter_begin']	0	359	pb_field_set_to_default	call site: 00025	/src/nanopb/pb_decode.c:944
0	43	2 : View List ['pb_make_string_substream', 'pb_close_string_substream']	0	390	pb_decode_ex	call site: 00010	/src/nanopb/pb_decode.c:1202
0	12	1 : View List ['pb_read']	0	12	pb_dec_bytes	call site: 00065	/src/nanopb/pb_decode.c:1548
0	12	1 : View List ['pb_read']	0	12	pb_dec_string	call site: 00079	/src/nanopb/pb_decode.c:1590
0	9	1 : View List ['pb_write']	0	9	pb_encode_submessage	call site: 00254	/src/nanopb/pb_encode.c:744
0	9	1 : View List ['pb_write']	0	9	encode_array	call site: 00221	/src/nanopb/pb_encode.c:177
0	5	1 : View List ['free_with_check']	0	5	realloc_with_check	call site: 00068	/src/nanopb/tests/build/common/malloc_wrappers.c:115
0	3	1 : View List ['safe_read_bool']	5	428	encode_field	call site: 00202	/src/nanopb/pb_encode.c:431

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

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', 'encode_field', 'pb_field_set_to_default', 'validate_message', 'pb_encode_tag_for_field', 'do_roundtrip', 'default_extension_decoder', 'decode_field', 'encode_array']

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', '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=['validate_message', 'pb_skip_field', 'decode_static_field', 'encode_field', 'pb_decode_inner', 'decode_pointer_field', 'do_roundtrip', 'pb_field_set_to_default']

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']

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

Directories in report

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