High level conclusions

Fuzzers reach 40.01% of cyclomatic complexity.

Fuzzers reach 38.52% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

94 / 244

Cyclomatic complexity statically reachable by fuzzers

481 / 1202

Runtime code coverage of functions

103 / 244

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: /src/tinyusb/test/fuzz/device/net_ncm/fuzz.c

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	1	50.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	1	50.0%
All colors	2	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
1	0	EP	call site: 00000	recv_validate_datagram

Runtime coverage analysis

Covered functions

152

Functions that are reachable but not covered

0

Reachable functions

2

Percentage of reachable functions covered

100.0%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c	1
/src/tinyusb/src/class/net/ncm_device.c	1

Fuzzer: /src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc

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	45	31.2%
gold	[1:9]	4	2.77%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	95	65.9%
All colors	144	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
6	87	tud_task_ext	call site: 00087	usbd_control_xfer_cb
5	72	process_get_status	call site: 00072	process_get_status
4	45	tud_control_xfer	call site: 00045	configuration_reset
3	115	stream_xfer	call site: 00115	stream_release
2	11	dcd_int_handler	call site: 00011	tu_fifo_write_n_access_mode
2	15	tu_fifo_write_n_access_mode	call site: 00015	tud_event_hook_cb
2	19	dcd_int_handler	call site: 00019	tud_task_ext
2	51	process_set_config	call site: 00051	tu_bind_driver_to_ep_itf
2	83	usbd_edpt_stall	call site: 00083	invoke_class_control
2	95	tud_task_ext	call site: 00095	cdc_task
1	8	tud_rhport_init	call site: 00008	dcd_int_handler
1	22	tud_task_ext	call site: 00022	tu_fifo_read_n_access_mode

Runtime coverage analysis

Covered functions

152

Functions that are reachable but not covered

9

Reachable functions

90

Percentage of reachable functions covered

90.0%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc	2
/src/tinyusb/test/fuzz/fuzz.cc	1
/src/tinyusb/src/tusb.c	12
/src/tinyusb/src/device/usbd.c	35
/src/tinyusb/src/common/tusb_fifo.c	10
/src/tinyusb/test/fuzz/dcd_fuzz.cc	9
/src/tinyusb/test/fuzz/usbd_fuzz.cc	4
/src/tinyusb/test/fuzz/device/cdc/src/usb_descriptors.cc	3
/src/tinyusb/src/class/cdc/cdc_device.c	12

Fuzzer: /src/tinyusb/test/fuzz/device/msc/src/fuzz.cc

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	34	35.0%
gold	[1:9]	4	4.12%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	59	60.8%
All colors	97	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
6	87	tud_task_ext	call site: 00087	usbd_control_xfer_cb
5	72	process_get_status	call site: 00072	process_get_status
4	45	tud_control_xfer	call site: 00045	configuration_reset
2	11	dcd_int_handler	call site: 00011	tu_fifo_write_n_access_mode
2	15	tu_fifo_write_n_access_mode	call site: 00015	tud_event_hook_cb
2	51	process_set_config	call site: 00051	tu_bind_driver_to_ep_itf
2	83	usbd_edpt_stall	call site: 00083	invoke_class_control
1	19	dcd_int_handler	call site: 00019	dcd_event_handler
1	22	tud_task_ext	call site: 00022	tu_fifo_read_n_access_mode
1	24	tu_fifo_read_n_access_mode	call site: 00024	correct_read_index
1	28	tud_task_ext	call site: 00028	usbd_reset
1	36	process_setup_received	call site: 00036	invoke_class_control

Runtime coverage analysis

Covered functions

152

Functions that are reachable but not covered

5

Reachable functions

60

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc	1
/src/tinyusb/test/fuzz/fuzz.cc	1
/src/tinyusb/src/tusb.c	2
/src/tinyusb/src/device/usbd.c	30
/src/tinyusb/src/common/tusb_fifo.c	8
/src/tinyusb/test/fuzz/dcd_fuzz.cc	9
/src/tinyusb/test/fuzz/usbd_fuzz.cc	4
/src/tinyusb/test/fuzz/device/msc/src/usb_descriptors.cc	3

Fuzzer: /src/tinyusb/test/fuzz/device/net/src/fuzz.cc

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	42	39.2%
gold	[1:9]	4	3.73%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	61	57.0%
All colors	107	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
6	87	tud_task_ext	call site: 00087	usbd_control_xfer_cb
5	72	process_get_status	call site: 00072	process_get_status
4	45	tud_control_xfer	call site: 00045	configuration_reset
4	102	net_task	call site: 00102	do_in_xfer
2	11	dcd_int_handler	call site: 00011	tu_fifo_write_n_access_mode
2	15	tu_fifo_write_n_access_mode	call site: 00015	tud_event_hook_cb
2	19	dcd_int_handler	call site: 00019	tud_task_ext
2	51	process_set_config	call site: 00051	tu_bind_driver_to_ep_itf
2	83	usbd_edpt_stall	call site: 00083	invoke_class_control
2	95	tud_task_ext	call site: 00095	net_task
1	0	EP	call site: 00000	fuzz_init
1	8	tud_rhport_init	call site: 00008	dcd_int_handler

Runtime coverage analysis

Covered functions

152

Functions that are reachable but not covered

7

Reachable functions

66

Percentage of reachable functions covered

89.39%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
/src/tinyusb/test/fuzz/device/net/src/fuzz.cc	2
/src/tinyusb/test/fuzz/fuzz.cc	1
/src/tinyusb/src/tusb.c	2
/src/tinyusb/src/device/usbd.c	30
/src/tinyusb/src/common/tusb_fifo.c	8
/src/tinyusb/test/fuzz/dcd_fuzz.cc	9
/src/tinyusb/test/fuzz/usbd_fuzz.cc	4
/src/tinyusb/test/fuzz/device/net/src/usb_descriptors.cc	3
/src/tinyusb/src/class/net/ecm_rndis_device.c	4
/src/tinyusb/test/fuzz/net_fuzz.cc	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
mscd_xfer_cb	/src/tinyusb/src/class/msc/msc_device.c	4	['char', 'char', 'int', 'int']	6	0	735	140	34	36	0	260	189
netd_xfer_cb	/src/tinyusb/src/class/net/ncm_device.c	4	['char', 'char', 'int', 'int']	4	0	91	18	7	18	0	95	69
rndis_class_set_handler	/src/tinyusb/lib/networking/rndis_reports.c	2	['N/A', 'int']	6	0	121	10	11	15	0	86	65
cdcd_xfer_cb	/src/tinyusb/src/class/cdc/cdc_device.c	4	['char', 'char', 'int', 'int']	4	0	449	72	23	26	0	137	49

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

Functions statically reachable by fuzzers

153 / 244

Cyclomatic complexity statically reachable by fuzzers

853 / 1202

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.

/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c

Dictionary

Use this with the libFuzzer -dict=DICT.file flag

/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc

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=['tud_task_ext', 'process_get_status', 'tud_control_xfer', 'stream_xfer', 'dcd_int_handler', 'tu_fifo_write_n_access_mode', 'process_set_config', 'usbd_edpt_stall']

/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc

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=['tud_task_ext', 'process_get_status', 'tud_control_xfer', 'dcd_int_handler', 'tu_fifo_write_n_access_mode', 'process_set_config', 'usbd_edpt_stall', 'tu_fifo_read_n_access_mode']

/src/tinyusb/test/fuzz/device/net/src/fuzz.cc

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=['tud_task_ext', 'process_get_status', 'tud_control_xfer', 'net_task', 'dcd_int_handler', 'tu_fifo_write_n_access_mode', 'process_set_config', 'usbd_edpt_stall']

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
netd_open	42	5	11.90%	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']
tud_task_ext	117	57	48.71%	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']
dcd_event_handler	74	32	43.24%	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']

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/tinyusb/src/tusb.c	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/test/fuzz/fuzz.cc	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/test/fuzz/device/net/src/fuzz.cc	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/test/fuzz/device/cdc/src/usb_descriptors.cc	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']
/src/tinyusb/test/fuzz/dcd_fuzz.cc	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/test/fuzz/msc_fuzz.cc	[]	[]
/src/tinyusb/test/fuzz/usbd_fuzz.cc	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc	['/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc']
/src/tinyusb/src/class/net/ecm_rndis_device.c	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/src/class/cdc/cdc_device.c	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']
/src/tinyusb/src/device/usbd.c	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/usr/local/bin/../include/c++/v1/optional	[]	[]
/src/tinyusb/lib/networking/rndis_reports.c	[]	[]
/src/tinyusb/src/class/msc/msc_device.c	[]	[]
/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc']
/src/tinyusb/src/class/net/ncm_device.c	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c']	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c']
/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c']	['/src/tinyusb/test/fuzz/device/net_ncm/fuzz.c']
/src/tinyusb/test/fuzz/device/net/src/usb_descriptors.cc	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/usr/local/bin/../include/c++/v1/stdexcept	[]	[]
/src/tinyusb/test/fuzz/net_fuzz.cc	['/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	[]
/src/tinyusb/src/common/tusb_fifo.c	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/cdc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc', '/src/tinyusb/test/fuzz/device/net/src/fuzz.cc']
/src/tinyusb/test/fuzz/device/msc/src/usb_descriptors.cc	['/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc']	['/src/tinyusb/test/fuzz/device/msc/src/fuzz.cc']

Directories in report

Directory
/src/tinyusb/src/
/src/tinyusb/test/fuzz/
/src/tinyusb/src/class/net/
/src/tinyusb/test/fuzz/device/msc/src/
/src/tinyusb/src/class/msc/
/src/tinyusb/test/fuzz/device/net/src/
/src/tinyusb/src/class/cdc/
/src/tinyusb/lib/networking/
/src/tinyusb/test/fuzz/device/net_ncm/
/src/tinyusb/src/common/
/src/tinyusb/src/device/
/src/tinyusb/test/fuzz/device/cdc/src/
/usr/local/bin/../include/c++/v1/