High level conclusions

Fuzzers reach 96.34% of cyclomatic complexity.

Fuzzers reach 92.38% of all functions.

Fuzzers reach 97.14% code coverage.

Reachability and coverage overview

Functions statically reachable by fuzzers

97 / 105

Cyclomatic complexity statically reachable by fuzzers

738 / 766

Runtime code coverage of functions

102 / 105

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	68	25.9%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	1	0.38%
lawngreen	50+	193	73.6%
All colors	262	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	127	validate_static	call site: 00127	validate_pointer
7	64	pb_field_iter_find_extension	call site: 00064	decode_extension
7	106	decode_static_field	call site: 00106	pb_message_set_to_defaults
6	165	pb_encode	call site: 00165	encode_extension_field
5	21	pb_message_set_to_defaults	call site: 00021	pb_message_set_to_defaults
5	81	pb_close_string_substream	call site: 00081	read_raw_value
2	14	pb_decode_inner	call site: 00014	pb_decode_tag
2	78	pb_skip_field	call site: 00078	pb_make_string_substream
2	103	decode_static_field	call site: 00103	pb_message_set_to_defaults
2	142	validate_message	call site: 00142	fprintf
2	199	pb_encode_tag_for_field	call site: 00199	encode_basic_field
2	227	do_roundtrip	call site: 00227	fprintf

Runtime coverage analysis

Covered functions

80

Functions that are reachable but not covered

17

Reachable functions

94

Percentage of reachable functions covered

81.91%

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	37
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	40	14.5%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	234	85.4%
All colors	274	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	127	validate_static	call site: 00127	validate_pointer
5	172	encode_field	call site: 00172	pb_check_proto3_default_value
3	110	pb_field_set_to_default	call site: 00110	pb_decode_inner
2	106	decode_static_field	call site: 00106	pb_message_set_to_defaults
2	142	validate_message	call site: 00142	fprintf
2	199	pb_encode_tag_for_field	call site: 00199	encode_basic_field
2	227	do_roundtrip	call site: 00227	fprintf
2	271	do_callback_decode	call site: 00271	get_alloc_count
1	22	pb_field_set_to_default	call site: 00022	pb_field_iter_begin
1	31	pb_decode_bool	call site: 00031	pb_decode_varint32_eof
1	68	default_extension_decoder	call site: 00068	decode_pointer_field
1	70	decode_field	call site: 00070	pb_skip_field

Runtime coverage analysis

Covered functions

92

Functions that are reachable but not covered

9

Reachable functions

95

Percentage of reachable functions covered

90.53%

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
tests/build/fuzztest/fuzztest.c	7
tests/build/common/malloc_wrappers.c	5
pb_decode.c	37
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	14	6.19%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	212	93.8%
All colors	226	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	149	decode_static_field	call site: 00149	pb_message_set_to_defaults
2	185	validate_message	call site: 00185	fprintf
2	202	do_decode	call site: 00202	fprintf
2	217	pb_decode	call site: 00217	fprintf
2	223	do_callback_decode	call site: 00223	get_alloc_count
1	24	pb_field_set_to_default	call site: 00024	pb_field_iter_begin
1	53	pb_decode_bool	call site: 00053	pb_decode_varint32_eof
1	77	realloc_with_check	call site: 00077	free_with_check
1	119	decode_field	call site: 00119	pb_skip_field

Runtime coverage analysis

Covered functions

73

Functions that are reachable but not covered

6

Reachable functions

74

Percentage of reachable functions covered

91.89%

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	41
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	77	25.6%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	223	74.3%
All colors	300	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	204	pb_encode	call site: 00204	encode_extension_field
8	161	validate_message	call site: 00161	__assert_fail
7	126	pb_skip_field	call site: 00126	pb_make_string_substream
7	136	pb_dec_submessage	call site: 00136	decode_basic_field
7	148	decode_static_field	call site: 00148	pb_message_set_to_defaults
5	21	pb_message_set_to_defaults	call site: 00021	pb_message_set_to_defaults
4	93	pb_field_iter_find_extension	call site: 00093	decode_extension
3	144	pb_message_set_to_defaults	call site: 00144	decode_basic_field
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	112	pb_close_string_substream	call site: 00112	allocate_field
2	117	decode_pointer_field	call site: 00117	decode_callback_field

Runtime coverage analysis

Covered functions

87

Functions that are reachable but not covered

16

Reachable functions

100

Percentage of reachable functions covered

84.0%

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	41
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	47	15.6%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	1	0.33%
lawngreen	50+	252	84.0%
All colors	300	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	161	validate_message	call site: 00161	__assert_fail
7	148	decode_static_field	call site: 00148	pb_message_set_to_defaults
6	137	decode_static_field	call site: 00137	decode_basic_field
5	211	encode_field	call site: 00211	pb_check_proto3_default_value
3	144	pb_message_set_to_defaults	call site: 00144	decode_basic_field
2	14	pb_decode_inner	call site: 00014	pb_decode_tag
2	184	validate_message	call site: 00184	fprintf
2	266	do_roundtrip	call site: 00266	fprintf
2	297	do_stream_decode	call site: 00297	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
1	51	pb_decode_bool	call site: 00051	pb_decode_varint32_eof

Runtime coverage analysis

Covered functions

97

Functions that are reachable but not covered

7

Reachable functions

100

Percentage of reachable functions covered

93.0%

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	41
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

97 / 105

Cyclomatic complexity statically reachable by fuzzers

738 / 766

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', 'decode_static_field', 'pb_encode', 'pb_message_set_to_defaults', 'pb_close_string_substream', '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_static', 'encode_field', 'pb_field_set_to_default', 'decode_static_field', 'validate_message', 'pb_encode_tag_for_field', 'do_roundtrip', 'do_callback_decode', 'pb_decode_bool']

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=['decode_static_field', 'validate_message', 'do_decode', 'pb_decode', 'do_callback_decode', 'pb_field_set_to_default', 'pb_decode_bool', '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', 'validate_message', 'pb_skip_field', 'pb_dec_submessage', 'decode_static_field', 'pb_message_set_to_defaults', 'pb_field_iter_find_extension', 'pb_decode_inner', 'pb_release_union_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', 'decode_static_field', 'encode_field', 'pb_message_set_to_defaults', 'pb_decode_inner', 'do_roundtrip', 'do_stream_decode', 'pb_field_set_to_default']

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

Directories in report

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