High level conclusions

Fuzzer fuzz_bundle is blocked:

The runtime code coverage of fuzz_bundle covers 15.88% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Fuzzer fuzz_object_store is blocked:

The runtime code coverage of fuzz_object_store covers 27.27% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Fuzzer fuzz_configfile is blocked:

The runtime code coverage of fuzz_configfile covers 23.33% 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

86 / 1448

Cyclomatic complexity statically reachable by fuzzers

306 / 4920

Runtime code coverage of functions

272 / 1448

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	Fuzzers runtime hit	Func lines hit %	I Count	BB Count	Cyclomatic complexity	Functions reached	Reached by functions	Accumulated cyclomatic complexity	Undiscovered complexity

Fuzzer: fuzz_repo

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	72	31.4%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	157	68.5%
All colors	229	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
16	185	dulwich.config.StackedConfig.default_backends	call site: 00185	dulwich.config.get_win_system_paths
11	127	dulwich.repo.Repo.__init__	call site: 00127	dulwich.object_store.DiskObjectStore.from_config
9	147	dulwich.repo.Repo.__init__	call site: 00147	dulwich.repo.parse_graftpoints
7	25	dulwich.repo.Repo.__init__	call site: 00025	os.path.isfile
6	33	dulwich.repo.Repo.__init__	call site: 00033	dulwich.repo.read_gitfile
4	44	dulwich.repo.Repo.get_named_file	call site: 00044	os.path.join
3	7	dulwich.repo.Repo.init	call site: 00007	ctypes.WINFUNCTYPE
3	207	dulwich.repo.Repo._init_maybe_bare	call site: 00207	test_utils.EnhancedFuzzedDataProvider.ConsumeRandomBytes
2	120	dulwich.config.ConfigDict._check_section_and_name	call site: 00120	subsection.encode
2	219	...dulwich.fuzzing.fuzz-targets.fuzz_repo.TestOneInput	call site: 00219	repo.do_commit
2	226	...dulwich.fuzzing.fuzz-targets.fuzz_repo.TestOneInput	call site: 00226	test_utils.EnhancedFuzzedDataProvider.ConsumeRandomInt
1	3	...dulwich.fuzzing.fuzz-targets.fuzz_repo.TestOneInput	call site: 00003	os.mkdir

Runtime coverage analysis

Covered functions

303

Functions that are reachable but not covered

77

Reachable functions

113

Percentage of reachable functions covered

31.86%

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
...dulwich.fuzzing.fuzz-targets.fuzz_repo	17
dulwich.repo	42
dulwich.object_store	6
dulwich.config	52
dulwich.file	7
dulwich.refs	3
dulwich.objects	3
dulwich.hooks	2

Fuzzer: fuzz_configfile

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	2	3.44%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	56	96.5%
All colors	58	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	0	EP	call site: 00000	dulwich.config.ConfigFile.from_file

Runtime coverage analysis

Covered functions

303

Functions that are reachable but not covered

23

Reachable functions

30

Percentage of reachable functions covered

23.33%

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
...dulwich.fuzzing.fuzz-targets.fuzz_configfile	3
dulwich.config	26

Fuzzer: fuzz_object_store

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	48	60.7%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	31	39.2%
All colors	79	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
19	59	dulwich.objects.S_ISGITLINK	call site: 00059	dulwich.patch.unified_diff
13	45	dulwich.patch.write_tree_diff	call site: 00045	dulwich.patch.write_object_diff
12	32	...dulwich.fuzzing.fuzz-targets.fuzz_object_store.TestOneInput	call site: 00032	dulwich.patch.write_tree_diff
2	0	EP	call site: 00000	dulwich.repo.MemoryRepo.__init__
2	10	dulwich.config.ConfigFile.__init__	call site: 00010	dulwich.objects.ShaFile.from_string

Runtime coverage analysis

Covered functions

302

Functions that are reachable but not covered

32

Reachable functions

44

Percentage of reachable functions covered

27.27%

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
...dulwich.fuzzing.fuzz-targets.fuzz_object_store	14
dulwich.repo	4
dulwich.refs	2
dulwich.object_store	1
dulwich.config	1
dulwich.objects	4
dulwich.patch	21

Fuzzer: fuzz_bundle

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	121	66.8%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	60	33.1%
All colors	181	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
53	12	dulwich.pack.pack_objects_to_data	call site: 00012	dulwich.pack.deltify_pack_objects
20	84	dulwich.pack.PackChunkGenerator._pack_data_chunks	call site: 00084	dulwich.pack.pack_object_chunks
16	163	...dulwich.fuzzing.fuzz-targets.fuzz_bundle.TestOneInput	call site: 00163	dulwich.bundle._read_bundle
10	126	dulwich.pack.read_pack_header	call site: 00126	dulwich.pack.PackStreamReader._buf_len
6	66	dulwich.pack.pack_objects_to_data	call site: 00066	dulwich.pack.full_unpacked_object
6	156	dulwich.bundle.write_bundle	call site: 00156	dulwich.pack.write_pack_data
4	137	dulwich.pack.read_pack_header	call site: 00137	dulwich.contrib.swift.SwiftPackReader.read
2	6	...dulwich.fuzzing.fuzz-targets.fuzz_bundle.TestOneInput	call site: 00006	test_utils.EnhancedFuzzedDataProvider.ConsumeRandomString
1	73	dulwich.pack.write_pack_objects	call site: 00073	dulwich.pack.PackChunkGenerator.__iter__
1	77	dulwich.pack.PackChunkGenerator.__init__	call site: 00077	.len
1	113	dulwich.pack.PackData.from_file	call site: 00113	dulwich.file.GitFile
1	117	dulwich.file._GitFile.__init__	call site: 00117	.getattr

Runtime coverage analysis

Covered functions

303

Functions that are reachable but not covered

90

Reachable functions

107

Percentage of reachable functions covered

15.89%

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.

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
...dulwich.fuzzing.fuzz-targets.fuzz_bundle	13
dulwich.pack	73
dulwich.file	7
dulwich.contrib.swift	4
dulwich.bundle	19

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
dulwich.client.GitClient.clone	dulwich.client	13	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	8	0	10	12	8	287	0	946	454
dulwich.porcelain.checkout_branch	dulwich.porcelain	3	['N/A', 'N/A', 'N/A']	10	0	12	7	6	195	0	640	368
dulwich.repo.BaseRepo.do_commit	dulwich.repo	14	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	6	0	13	20	11	179	0	582	308
dulwich.porcelain.upload_pack	dulwich.porcelain	3	['N/A', 'N/A', 'N/A']	8	0	2	2	4	232	1	754	276
dulwich.porcelain.pull	dulwich.porcelain	11	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	9	0	4	5	5	165	1	536	234
dulwich.object_store.DiskObjectStore._complete_pack	dulwich.object_store	6	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	8	0	13	3	4	121	2	379	187
dulwich.refs.RefsContainer.import_refs	dulwich.refs	8	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	6	0	4	3	4	103	0	341	176

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

Functions statically reachable by fuzzers

373 / 1448

Cyclomatic complexity statically reachable by fuzzers

1340 / 4920

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	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/dulwich/fuzzing/fuzz-targets/fuzz_repo.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=['dulwich.config.StackedConfig.default_backends', 'dulwich.repo.Repo.__init__', 'dulwich.repo.Repo.get_named_file', 'dulwich.repo.Repo.init', 'dulwich.repo.Repo._init_maybe_bare', 'dulwich.config.ConfigDict._check_section_and_name', '...dulwich.fuzzing.fuzz-targets.fuzz_repo.TestOneInput']

/src/dulwich/fuzzing/fuzz-targets/fuzz_configfile.py

Dictionary

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

/src/dulwich/fuzzing/fuzz-targets/fuzz_object_store.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=['dulwich.objects.S_ISGITLINK', 'dulwich.patch.write_tree_diff', '...dulwich.fuzzing.fuzz-targets.fuzz_object_store.TestOneInput', 'dulwich.config.ConfigFile.__init__']

/src/dulwich/fuzzing/fuzz-targets/fuzz_bundle.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=['dulwich.pack.pack_objects_to_data', 'dulwich.pack.PackChunkGenerator._pack_data_chunks', '...dulwich.fuzzing.fuzz-targets.fuzz_bundle.TestOneInput', 'dulwich.pack.read_pack_header', 'dulwich.bundle.write_bundle', 'dulwich.pack.write_pack_objects', 'dulwich.pack.PackChunkGenerator.__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
dulwich.repo.Repo.stage	39	21	53.84%	[]
dulwich.repo.Repo.clone	40	0	0.0%	[]
o.check	42	23	54.76%	[]
dulwich.objects.parse_commit	34	5	14.70%	[]
dulwich.object_store.DiskObjectStore._complete_pack	31	0	0.0%	[]
dulwich.pack.read_zlib_chunks	32	0	0.0%	[]
dulwich.pack.unpack_object	32	0	0.0%	[]
dulwich.pack.PackChunkGenerator._pack_data_chunks	38	10	26.31%	['fuzz_bundle']
dulwich.pack.apply_delta.get_delta_header_size	43	0	0.0%	[]
dulwich.pack.write_pack_index_v2	31	7	22.58%	[]
dulwich.refs.DiskRefsContainer.set_if_equals	33	0	0.0%	[]
dulwich.refs.DiskRefsContainer.remove_if_equals	33	0	0.0%	[]
dulwich.patch.parse_patch_message	33	0	0.0%	[]
dulwich.bundle._read_bundle	31	0	0.0%	['fuzz_bundle']

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
	[]	[]
os	[]	[]
collections	[]	[]
dulwich.graph	[]	[]
dulwich.contrib.diffstat	[]	[]
gzip	[]	[]
dulwich.bundle	['fuzz_bundle']	[]
re	[]	[]
dulwich.server	[]	[]
dulwich.objects	['fuzz_repo', 'fuzz_object_store']	[]
winreg	[]	[]
datetime	[]	[]
fastimport	[]	[]
io	[]	[]
dulwich.lfs	[]	[]
dulwich.patch	['fuzz_object_store']	[]
zlib	[]	[]
gevent	[]	[]
itertools	[]	[]
dulwich.credentials	[]	[]
posixpath	[]	[]
...dulwich.fuzzing.fuzz-targets.fuzz_bundle	['fuzz_bundle']	[]
paramiko	[]	[]
dulwich	[]	[]
win32api	[]	[]
mmap	[]	[]
dulwich.pack	['fuzz_bundle']	[]
pathlib	[]	[]
geventhttpclient	[]	[]
wsgiref	[]	[]
difflib	[]	[]
dulwich.cloud.gcs	[]	[]
dulwich.config	['fuzz_repo', 'fuzz_configfile', 'fuzz_object_store']	[]
dulwich.refs	['fuzz_repo', 'fuzz_object_store']	[]
dulwich.archive	[]	[]
dulwich.porcelain	[]	[]
dulwich.cli	[]	[]
dulwich.contrib.release_robot	[]	[]
hashlib	[]	[]
dulwich.objectspec	[]	[]
dulwich.errors	[]	[]
select	[]	[]
dulwich.index	[]	[]
dulwich.hooks	['fuzz_repo']	[]
msvcrt	[]	[]
dulwich.client	[]	[]
...dulwich.fuzzing.fuzz-targets.fuzz_configfile	['fuzz_configfile']	[]
shlex	[]	[]
dulwich.diff_tree	[]	[]
...dulwich.fuzzing.fuzz-targets.fuzz_object_store	['fuzz_object_store']	[]
heapq	[]	[]
gpg	[]	[]
dulwich.reflog	[]	[]
atheris	[]	[]
stat	[]	[]
copy	[]	[]
subprocess	[]	[]
dulwich.log_utils	[]	[]
dulwich.greenthreads	[]	[]
contextlib	[]	[]
fnmatch	[]	[]
functools	[]	[]
dulwich.line_ending	[]	[]
dulwich.cloud	[]	[]
ctypes	[]	[]
time	[]	[]
cdifflib	[]	[]
tarfile	[]	[]
warnings	[]	[]
dulwich.walk	[]	[]
dulwich.file	['fuzz_repo', 'fuzz_bundle']	[]
json	[]	[]
dulwich.contrib.requests_vendor	[]	[]
ipaddress	[]	[]
dulwich.mailmap	[]	[]
test_utils	[]	[]
dulwich.protocol	[]	[]
argparse	[]	[]
pdb	[]	[]
optparse	[]	[]
tempfile	[]	[]
shutil	[]	[]
dulwich.repo	['fuzz_repo', 'fuzz_object_store']	[]
dulwich.lru_cache	[]	[]
pwd	[]	[]
dulwich.contrib.swift	['fuzz_bundle']	[]
...dulwich.fuzzing.fuzz-targets.fuzz_repo	['fuzz_repo']	[]
urllib	[]	[]
binascii	[]	[]
getopt	[]	[]
dulwich.submodule	[]	[]
signal	[]	[]
dulwich.web	[]	[]
platform	[]	[]
urllib3	[]	[]
dulwich.fastexport	[]	[]
dulwich.object_store	['fuzz_repo', 'fuzz_object_store']	[]
	[]	[]
struct	[]	[]
sys	[]	[]
socketserver	[]	[]
dulwich.ignore	[]	[]
dulwich.stash	[]	[]
typing	[]	[]
logging	[]	[]
configparser	[]	[]
requests	[]	[]
socket	[]	[]
dulwich.__main__	[]	[]
dulwich.contrib	[]	[]
dulwich.contrib.paramiko_vendor	[]	[]

Directories in report

Directory