Fuzz introspector
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Project coverage

Table of contents

Project overview: face
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: fuzz_parse
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Fuzzer: fuzz_command
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/fuzz_parse.py
Dictionary
Fuzzer function priority
/src/fuzz_command.py
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2025-07-01

Project overview: face

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
25.0%
33 / 131
Cyclomatic complexity statically reachable by fuzzers
27.0%
131 / 485
Runtime code coverage of functions
53.0%
69 / 131

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.

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
fuzz_parse /src/fuzz_parse.py 73 246 6 6 34 229 fuzz_parse.py
fuzz_command /src/fuzz_command.py 106 214 7 7 86 347 fuzz_command.py

Project functions overview

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 details

Fuzzer: fuzz_parse

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

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 39 35.7%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 70 64.2%
All colors 109 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
21 70 face.parser.Parser._parse_flags call site: 00070 face.parser.Parser._parse_flagfile
6 0 EP call site: 00000 face.parser.Parser.parse
4 28 face.sinter.get_fb call site: 00028 inspect.isbuiltin
3 41 face.command.Command.get_dep_names call site: 00041 face.sinter.get_arg_names
2 100 face.parser.Parser._resolve_flags call site: 00100 ff_paths.append
1 16 face.parser.Parser._parse_subcmds call site: 00016 ret.append
1 52 face.command.Command.get_dep_names call site: 00052 collections.OrderedDict
1 96 face.parser.Parser._resolve_flags call site: 00096 missing_flags.append

Runtime coverage analysis

Covered functions
83
Functions that are reachable but not covered
58
Reachable functions
73
Percentage of reachable functions covered
20.55%
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
...fuzz_parse 6
face.parser 43
face.command 9
face.sinter 10
face.utils 10

Fuzzer: fuzz_command

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

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 85 41.4%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 120 58.5%
All colors 205 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
21 166 face.parser.Parser._parse_flags call site: 00166 face.parser.Parser._parse_flagfile
18 35 face.sinter.get_fb call site: 00035 face.command.Command.add
11 12 face.middleware.is_middleware call site: 00012 face.command.Command.add_middleware
7 62 face.command.Command.__init__ call site: 00062 face.utils.unwrap_text
4 25 face.sinter.get_fb call site: 00025 inspect.isbuiltin
4 57 face.command.Command.__init__ call site: 00057 .isinstance
3 78 face.command.Command.add call site: 00078 face.command.Command.add_command
3 106 face.parser.FlagDisplay.__init__ call site: 00106 face.utils.get_type_desc
3 142 face.command.Command.get_dep_names call site: 00142 face.sinter.get_arg_names
2 112 face.command.Command.add call site: 00112 fdp.ConsumeUnicodeNoSurrogates
2 196 face.parser.Parser._resolve_flags call site: 00196 ff_paths.append
1 55 face.command.Command.add call site: 00055 face.command.Command.__init__

Runtime coverage analysis

Covered functions
84
Functions that are reachable but not covered
80
Reachable functions
106
Percentage of reachable functions covered
24.53%
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
/ 1
...fuzz_command 8
face.command 27
face.middleware 9
face.sinter 13
face.utils 21
face.parser 50

Analyses and suggestions

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
face.command.Command.run face.command 4 ['N/A', 'N/A', 'N/A', 'N/A'] 7 0 6 9 7 110 0 358 144
face.testing.CommandChecker.run face.testing 6 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 3 0 3 7 6 31 1 104 86
face.helpers.StoutHelpFormatter.get_help_text face.helpers 4 ['N/A', 'N/A', 'N/A', 'N/A'] 6 0 12 6 5 26 1 87 75
face.parser.Parser.__init__ face.parser 7 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 7 0 2 4 5 69 0 245 62
face.utils.prompt face.utils 5 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 5 0 1 3 4 14 1 50 44

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

Functions statically reachable by fuzzers
60.0%
79 / 131
Cyclomatic complexity statically reachable by fuzzers
65.0%
314 / 485

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

Fuzz engine guidance

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/fuzz_parse.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=['face.parser.Parser._parse_flags', 'face.sinter.get_fb', 'face.command.Command.get_dep_names', 'face.parser.Parser._resolve_flags', 'face.parser.Parser._parse_subcmds']

/src/fuzz_command.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=['face.parser.Parser._parse_flags', 'face.sinter.get_fb', 'face.middleware.is_middleware', 'face.command.Command.__init__', 'face.command.Command.add', 'face.parser.FlagDisplay.__init__', 'face.command.Command.get_dep_names']

Runtime coverage analysis

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
boltons.iterutils.unique.replace 550 126 22.90% ['fuzz_parse']
boltons.typeutils.make_sentinel 55 27 49.09% ['fuzz_parse', 'fuzz_command']
boltons.strutils.camel2under.lower 386 78 20.20% ['fuzz_parse', 'fuzz_command']
face.testing.CommandChecker._isolate 31 0 0.0% []
face.testing.CommandChecker.run 33 0 0.0% []
boltons.setutils.complement 595 107 17.98% ['fuzz_parse', 'fuzz_command']
boltons.funcutils.FunctionBuilder.from_func 365 100 27.39% ['fuzz_parse', 'fuzz_command']
face.command.Command.run 38 0 0.0% []
boltons.dictutils.OrderedMultiDict.update_extend 560 161 28.74% ['fuzz_parse', 'fuzz_command']
face.helpers.StoutHelpFormatter.get_help_text 40 0 0.0% []

Files and Directories in report

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
boltons [] []
[] []
fcntl [] []
face.errors [] []
re [] []
atheris [] []
face.middleware ['fuzz_command'] []
inspect [] []
textwrap [] []
face.command ['fuzz_parse', 'fuzz_command'] []
sys [] []
...fuzz_command ['fuzz_command'] []
os [] []
face.utils ['fuzz_parse', 'fuzz_command'] []
face.helpers [] []
face.sinter ['fuzz_parse', 'fuzz_command'] []
...fuzz_parse ['fuzz_parse'] []
functools [] []
shlex [] []
subprocess [] []
codecs [] []
csv [] []
io [] []
collections [] []
face [] []
[] []
face.parser ['fuzz_parse', 'fuzz_command'] []
array [] []
hashlib [] []
keyword [] []
face.testing [] []

Directories in report

Directory

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file
fuzz_parse fuzzerLogFile-fuzz_parse.data fuzzerLogFile-fuzz_parse.data.yaml all_cov.json
fuzz_command fuzzerLogFile-fuzz_command.data fuzzerLogFile-fuzz_command.data.yaml all_cov.json