High level conclusions

Fuzzer fuzz_core is blocked:

The runtime code coverage of fuzz_core covers 1.315% 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_glom is blocked:

The runtime code coverage of fuzz_glom covers 1.428% 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_mutation is blocked:

The runtime code coverage of fuzz_mutation covers 1.351% 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_reduction is blocked:

The runtime code coverage of fuzz_reduction covers 2.5% 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_matching is blocked:

The runtime code coverage of fuzz_matching covers 0.0% 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

34 / 305

Cyclomatic complexity statically reachable by fuzzers

134 / 1054

Runtime code coverage of functions

14 / 305

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_matching

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	60.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	2	40.0%
All colors	5	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
3	1	...fuzz_matching.TestOneInput	call site: 00001	glom.matching.Match

Runtime coverage analysis

Covered functions

15

Functions that are reachable but not covered

5

Reachable functions

5

Percentage of reachable functions covered

0.0%

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
/	1
...fuzz_matching	4

Fuzzer: fuzz_reduction

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	131	82.9%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	27	17.0%
All colors	158	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
99	8	...fuzz_reduction.test_flatten	call site: 00008	glom.core.glom
18	109	glom.mutation._apply_for_each	call site: 00109	glom.mutation.Delete.glomit
10	147	...fuzz_reduction.test_merge	call site: 00147	glom.core.glom
3	128	...fuzz_reduction.TestOneInput	call site: 00128	atheris.FuzzedDataProvider
1	135	...fuzz_reduction.test_merge	call site: 00135	fdp.ConsumeUnicodeNoSurrogates

Runtime coverage analysis

Covered functions

16

Functions that are reachable but not covered

78

Reachable functions

80

Percentage of reachable functions covered

2.5%

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_reduction	11
glom.reduction	16
glom.core	47
glom.matching	1
glom.mutation	17

Fuzzer: fuzz_mutation

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	117	90.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	13	10.0%
All colors	130	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
89	2	...fuzz_mutation.TestOneInput	call site: 00002	glom.core.glom
28	93	glom.mutation._apply_for_each	call site: 00093	glom.mutation.Delete.glomit

Runtime coverage analysis

Covered functions

15

Functions that are reachable but not covered

73

Reachable functions

74

Percentage of reachable functions covered

1.35%

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_mutation	6
glom.mutation	19
glom.core	47
glom.matching	1
glom.reduction	7

Fuzzer: fuzz_glom

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	111	92.5%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	9	7.5%
All colors	120	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
65	3	...fuzz_glom.TestOneInput	call site: 00003	glom.core._glom
46	70	glom.mutation._apply_for_each	call site: 00070	glom.mutation.Assign.glomit

Runtime coverage analysis

Covered functions

15

Functions that are reachable but not covered

69

Reachable functions

70

Percentage of reachable functions covered

1.43%

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_glom	5
glom.core	47
glom.matching	1
glom.mutation	17
glom.reduction	7

Fuzzer: fuzz_core

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	112	86.1%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	18	13.8%
All colors	130	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
74	4	...fuzz_core.TestOneInput	call site: 00004	glom.core._glom
37	80	glom.mutation._apply_for_each	call site: 00080	glom.mutation.Assign.glomit
1	120	...fuzz_core.TestOneInput	call site: 00120	fdp.ConsumeUnicodeNoSurrogates

Runtime coverage analysis

Covered functions

15

Functions that are reachable but not covered

75

Reachable functions

76

Percentage of reachable functions covered

1.32%

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_core	9
glom.core	47
glom.matching	1
glom.reduction	9
glom.mutation	17

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
glom.core.GlomError.__str__	glom.core	1	['N/A']	5	0	1	2	4	33	0	111	82
glom.cli.mw_get_target	glom.cli	6	['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A']	3	0	0	13	8	27	0	94	71
glom.core._format_t	glom.core	2	['N/A', 'N/A']	4	0	7	11	7	15	4	60	45
glom.matching._glom_match	glom.matching	3	['N/A', 'N/A', 'N/A']	4	0	2	12	8	17	0	62	35

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

Functions statically reachable by fuzzers

55 / 305

Cyclomatic complexity statically reachable by fuzzers

228 / 1054

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/fuzz_matching.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=['...fuzz_matching.TestOneInput']

/src/fuzz_reduction.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=['...fuzz_reduction.test_flatten', 'glom.mutation._apply_for_each', '...fuzz_reduction.test_merge', '...fuzz_reduction.TestOneInput']

/src/fuzz_mutation.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=['...fuzz_mutation.TestOneInput', 'glom.mutation._apply_for_each']

/src/fuzz_glom.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=['...fuzz_glom.TestOneInput', 'glom.mutation._apply_for_each']

/src/fuzz_core.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=['...fuzz_core.TestOneInput', 'glom.mutation._apply_for_each']

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.typeutils.make_sentinel	55	28	50.90%	['fuzz_mutation', 'fuzz_core', 'fuzz_matching', 'fuzz_glom', 'fuzz_reduction']
face.helpers.get_wrap_width	177	67	37.85%	['fuzz_mutation', 'fuzz_core', 'fuzz_matching', 'fuzz_glom', 'fuzz_reduction']
boltons.iterutils.is_scalar	550	89	16.18%	['fuzz_mutation', 'fuzz_core', 'fuzz_matching', 'fuzz_glom', 'fuzz_reduction']
boltons.funcutils.FunctionBuilder.from_func	365	66	18.08%	['fuzz_mutation', 'fuzz_core', 'fuzz_matching', 'fuzz_glom', 'fuzz_reduction']
face.utils.isatty	210	53	25.23%	['fuzz_mutation', 'fuzz_core', 'fuzz_matching', 'fuzz_glom', 'fuzz_reduction']

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
	[]	[]
sys	[]	[]
tomli	[]	[]
glom._version	[]	[]
glom.core	['fuzz_reduction', 'fuzz_mutation', 'fuzz_glom', 'fuzz_core']	[]
traceback	[]	[]
random	[]	[]
copy	[]	[]
re	[]	[]
collections	[]	[]
tomllib	[]	[]
os	[]	[]
glom.tutorial	[]	[]
json	[]	[]
boltons	[]	[]
glom.__main__	[]	[]
...fuzz_reduction	['fuzz_reduction']	[]
reprlib	[]	[]
...fuzz_mutation	['fuzz_mutation']	[]
...fuzz_glom	['fuzz_glom']	[]
atheris	[]	[]
glom.matching	['fuzz_reduction', 'fuzz_mutation', 'fuzz_glom', 'fuzz_core']	[]
warnings	[]	[]
attr	[]	[]
glom	[]	[]
string	[]	[]
face	[]	[]
glom.mutation	['fuzz_reduction', 'fuzz_mutation', 'fuzz_glom', 'fuzz_core']	[]
itertools	[]	[]
glom.reduction	['fuzz_reduction', 'fuzz_mutation', 'fuzz_glom', 'fuzz_core']	[]
glom.streaming	[]	[]
yaml	[]	[]
glom.cli	[]	[]
glom.grouping	[]	[]
...fuzz_core	['fuzz_core']	[]
pdb	[]	[]
ast	[]	[]
...fuzz_matching	['fuzz_matching']	[]
	[]	[]
abc	[]	[]

Directories in report

Directory