High level conclusions

Fuzzer fuzz_websocket_parser is blocked:

The runtime code coverage of fuzz_websocket_parser covers 22.72% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Reachability and coverage overview

Functions statically reachable by fuzzers

13 / 507

Cyclomatic complexity statically reachable by fuzzers

53 / 1850

Runtime code coverage of functions

46 / 507

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: fuzz_http11_response_parser

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	15	30.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	35	70.0%
All colors	50	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
7	30	websockets.http11.read_body	call site: 00030	websockets.http11.parse_line
3	42	websockets.http11.read_body	call site: 00042	websockets.streams.StreamReader.read_exact
2	17	websockets.datastructures.Headers.update	call site: 00017	.isinstance
2	39	websockets.streams.StreamReader.read_exact	call site: 00039	websockets.http11.parse_headers
1	46	websockets.http11.read_body	call site: 00046	.len

Runtime coverage analysis

Covered functions

58

Functions that are reachable but not covered

22

Reachable functions

34

Percentage of reachable functions covered

35.29%

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
/	1
...inspector.light.source_files.src.websockets.fuzzing.fuzz_http11_response_parser	6
websockets.streams	2
websockets.http11	22
websockets.datastructures	5

Fuzzer: fuzz_http11_request_parser

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	3	10.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	27	90.0%
All colors	30	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	15	websockets.datastructures.Headers.update	call site: 00015	.isinstance
1	26	websockets.http11.parse_headers	call site: 00026	.int

Runtime coverage analysis

Covered functions

58

Functions that are reachable but not covered

19

Reachable functions

28

Percentage of reachable functions covered

32.14%

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
/	1
...inspector.light.source_files.src.websockets.fuzzing.fuzz_http11_request_parser	6
websockets.streams	2
websockets.http11	15
websockets.datastructures	5

Fuzzer: fuzz_websocket_parser

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	31.4%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	24	68.5%
All colors	35	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	23	websockets.frames.Frame.parse	call site: 00023	.len
1	3	...inspector.light.source_files.src.websockets.fuzzing.fuzz_websocket_parser.test_one_input	call site: 00003	fdp.ConsumeInt
1	5	...inspector.light.source_files.src.websockets.fuzzing.fuzz_websocket_parser.test_one_input	call site: 00005	websockets.streams.StreamReader.__init__
1	7	websockets.streams.StreamReader.__init__	call site: 00007	websockets.streams.StreamReader.feed_data
1	30	websockets.frames.Frame.parse	call site: 00030	extension.decode
1	32	websockets.frames.Frame.parse	call site: 00032	.next

Runtime coverage analysis

Covered functions

58

Functions that are reachable but not covered

17

Reachable functions

22

Percentage of reachable functions covered

22.73%

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
/	1
...inspector.light.source_files.src.websockets.fuzzing.fuzz_websocket_parser	10
websockets.streams	2
websockets.frames	8
websockets.utils	2

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
websockets.legacy.server.WebSocketServerProtocol.handler	websockets.legacy.server	1	['N/A']	11	0	22	9	7	163	1	545	470
websockets.sync.client.unix_connect	websockets.sync.client	3	['N/A', 'N/A', 'N/A']	8	0	1	2	4	99	0	337	211
websockets.protocol.Protocol.__init__	websockets.protocol	5	['N/A', 'N/A', 'N/A', 'N/A', 'N/A']	7	0	4	2	4	110	0	374	111
websockets.cli.main	websockets.cli	1	['N/A']	4	0	7	3	4	36	1	117	87
websockets.asyncio.client.connect.__await_impl__	websockets.asyncio.client	1	['N/A']	4	0	4	2	4	52	1	179	73
websockets.asyncio.connection.Connection.send	websockets.asyncio.connection	3	['N/A', 'N/A', 'N/A']	9	0	24	19	11	61	0	218	59
websockets.asyncio.server.basic_auth.process_request	websockets.asyncio.server	2	['N/A', 'N/A']	3	0	1	2	4	22	0	71	47
websockets.legacy.client.WebSocketClientProtocol.handshake	websockets.legacy.client	6	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	12	0	6	9	7	156	0	518	45
websockets.sync.connection.Connection.keepalive	websockets.sync.connection	1	['N/A']	4	0	7	6	5	20	0	73	45
websockets.asyncio.connection.Connection.data_received	websockets.asyncio.connection	2	['N/A', 'N/A']	10	0	5	4	5	64	0	220	44

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

Functions statically reachable by fuzzers

162 / 507

Cyclomatic complexity statically reachable by fuzzers

656 / 1850

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/inspector/light/source_files/src/websockets/fuzzing/fuzz_http11_response_parser.py

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=['websockets.http11.read_body', 'websockets.datastructures.Headers.update', 'websockets.streams.StreamReader.read_exact']

/src/inspector/light/source_files/src/websockets/fuzzing/fuzz_http11_request_parser.py

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=['websockets.datastructures.Headers.update', 'websockets.http11.parse_headers']

/src/inspector/light/source_files/src/websockets/fuzzing/fuzz_websocket_parser.py

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=['websockets.frames.Frame.parse', '...inspector.light.source_files.src.websockets.fuzzing.fuzz_websocket_parser.test_one_input', 'websockets.streams.StreamReader.__init__']

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
websockets.http11.read_body	33	6	18.18%	['fuzz_websocket_parser', 'fuzz_http11_response_parser', 'fuzz_http11_request_parser']

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
	[]	[]
websockets.uri	[]	[]
pathlib	[]	[]
websockets.version	[]	[]
websockets.server	[]	[]
websockets.streams	['fuzz_http11_response_parser', 'fuzz_http11_request_parser', 'fuzz_websocket_parser']	[]
websockets.utils	['fuzz_websocket_parser']	[]
secrets	[]	[]
websockets.asyncio.client	[]	[]
websockets	[]	[]
random	[]	[]
inspect	[]	[]
argparse	[]	[]
ipaddress	[]	[]
websockets.asyncio.router	[]	[]
time	[]	[]
websockets.legacy.client	[]	[]
websockets.asyncio.compatibility	[]	[]
http	[]	[]
websockets.headers	[]	[]
websockets.imports	[]	[]
websockets.legacy.framing	[]	[]
websockets.legacy.exceptions	[]	[]
hmac	[]	[]
subprocess	[]	[]
websockets.exceptions	[]	[]
threading	[]	[]
websockets.legacy.protocol	[]	[]
websockets.sync.router	[]	[]
re	[]	[]
websockets.connection	[]	[]
...inspector.light.source_files.src.websockets.fuzzing.fuzz_http11_request_parser	['fuzz_http11_request_parser']	[]
socket	[]	[]
...inspector.light.source_files.src.websockets.fuzzing.fuzz_http11_response_parser	['fuzz_http11_response_parser']	[]
websockets.extensions	[]	[]
websockets.frames	['fuzz_websocket_parser']	[]
sys	[]	[]
websockets.http	[]	[]
functools	[]	[]
	[]	[]
websockets.sync.connection	[]	[]
warnings	[]	[]
...inspector.light.source_files.src.websockets.fuzzing.fuzz_websocket_parser	['fuzz_websocket_parser']	[]
struct	[]	[]
websockets.legacy.handshake	[]	[]
speedups	[]	[]
websockets.legacy	[]	[]
websockets.asyncio.server	[]	[]
base64	[]	[]
websockets.extensions.base	[]	[]
uuid	[]	[]
websockets.__main__	[]	[]
ssl	[]	[]
websockets.datastructures	['fuzz_http11_response_parser', 'fuzz_http11_request_parser']	[]
zlib	[]	[]
websockets.auth	[]	[]
websockets.extensions.permessage_deflate	[]	[]
websockets.sync.utils	[]	[]
websockets.asyncio.connection	[]	[]
websockets.typing	[]	[]
websockets.http11	['fuzz_http11_response_parser', 'fuzz_http11_request_parser']	[]
websockets.sync.messages	[]	[]
logging	[]	[]
typing	[]	[]
websockets.sync	[]	[]
os	[]	[]
hashlib	[]	[]
websockets.cli	[]	[]
websockets.client	[]	[]
selectors	[]	[]
collections	[]	[]
traceback	[]	[]
websockets.legacy.auth	[]	[]
websockets.sync.server	[]	[]
websockets.legacy.server	[]	[]
websockets.asyncio.messages	[]	[]
codecs	[]	[]
websockets.asyncio	[]	[]
io	[]	[]
websockets.protocol	[]	[]
websockets.sync.client	[]	[]
websockets.asyncio.async_timeout	[]	[]
atheris	[]	[]
python_socks	[]	[]
asyncio	[]	[]
queue	[]	[]
websockets.legacy.http	[]	[]

Directories in report

Directory