High level conclusions

Fuzzer fuzz_xslt is blocked:

The runtime code coverage of fuzz_xslt 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.

Fuzzer fuzz_schematron is blocked:

The runtime code coverage of fuzz_schematron covers 19.04% 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_xml_parse is blocked:

The runtime code coverage of fuzz_xml_parse 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.

Fuzzer fuzz_html_parse is blocked:

The runtime code coverage of fuzz_html_parse 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.

Fuzzer fuzz_sax is blocked:

The runtime code coverage of fuzz_sax 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.

Fuzzer fuzz_xmlschema is blocked:

The runtime code coverage of fuzz_xmlschema covers 16.66% 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

20 / 318

Cyclomatic complexity statically reachable by fuzzers

75 / 1153

Runtime code coverage of functions

14 / 318

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_xmlschema

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	25.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	6	75.0%
All colors	8	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	4	...fuzz_xmlschema.TestOneInput	call site: 00004	etree.XMLSchema

Runtime coverage analysis

Covered functions

10

Functions that are reachable but not covered

5

Reachable functions

6

Percentage of reachable functions covered

16.67%

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
/	1
...fuzz_xmlschema	5

Fuzzer: fuzz_sax

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	53	91.3%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	5	8.62%
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
53	2	...fuzz_sax.TestOneInput	call site: 00002	lxml.sax.ElementTreeProducer.saxify

Runtime coverage analysis

Covered functions

9

Functions that are reachable but not covered

46

Reachable functions

46

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.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
/	1
...fuzz_sax	7
lxml.sax	38

Fuzzer: fuzz_html_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	0	0.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	6	100.%
All colors	6	100

Runtime coverage analysis

Covered functions

9

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_html_parse	4

Fuzzer: fuzz_xml_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	1	16.6%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	5	83.3%
All colors	6	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	2	...fuzz_xml_parse.TestOneInput	call site: 00002	etree.ElementTree

Runtime coverage analysis

Covered functions

9

Functions that are reachable but not covered

6

Reachable functions

6

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_xml_parse	5

Fuzzer: fuzz_schematron

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	14	58.3%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	10	41.6%
All colors	24	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
10	12	lxml.isoschematron.Schematron.__init__	call site: 00012	lxml.isoschematron._stylesheet_param_dict
3	2	...fuzz_schematron.TestOneInput	call site: 00002	lxml.isoschematron.Schematron.__init__
1	8	lxml.isoschematron.Schematron.__init__	call site: 00008	_etree.parse

Runtime coverage analysis

Covered functions

10

Functions that are reachable but not covered

17

Reachable functions

21

Percentage of reachable functions covered

19.05%

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_schematron	5
lxml.isoschematron	15

Fuzzer: fuzz_xslt

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	0	0.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	6	100.%
All colors	6	100

Runtime coverage analysis

Covered functions

8

Functions that are reachable but not covered

4

Reachable functions

4

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_xslt	3

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
lxml.html._diffcommand.main	lxml.html._diffcommand	1	['N/A']	6	0	5	5	5	115	1	379	367
lxml.doctestcompare.LXMLOutputChecker.output_difference	lxml.doctestcompare	4	['N/A', 'N/A', 'N/A', 'N/A']	5	0	3	3	4	48	0	163	139
lxml.ElementInclude._include	lxml.ElementInclude	5	['N/A', 'N/A', 'N/A', 'N/A', 'N/A']	3	0	2	15	9	22	2	82	73
lxml.html.soupparser._parse	lxml.html.soupparser	4	['N/A', 'N/A', 'N/A', 'N/A']	2	0	0	6	5	23	3	78	69
lxml.html.HtmlMixin.rewrite_links	lxml.html	4	['N/A', 'N/A', 'N/A', 'N/A']	7	0	4	7	6	24	3	90	65
lxml.html._html5builder.TreeBuilder.insertRoot	lxml.html._html5builder	2	['N/A', 'N/A']	3	0	7	2	4	26	0	91	52
lxml.html.formfill._fill_form	lxml.html.formfill	2	['N/A', 'N/A']	3	0	2	7	6	19	2	69	50

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

Functions statically reachable by fuzzers

100 / 318

Cyclomatic complexity statically reachable by fuzzers

401 / 1153

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/fuzz_xmlschema.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_xmlschema.TestOneInput']

/src/fuzz_sax.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_sax.TestOneInput']

/src/fuzz_html_parse.py

Dictionary

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

/src/fuzz_xml_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=['...fuzz_xml_parse.TestOneInput']

/src/fuzz_schematron.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=['lxml.isoschematron.Schematron.__init__', '...fuzz_schematron.TestOneInput']

/src/fuzz_xslt.py

Dictionary

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

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
schema.validate	32	13	40.62%	['fuzz_xmlschema']
schematron.validate	32	12	37.5%	['fuzz_schematron']

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
	[]	[]
lxml.isoschematron	['fuzz_schematron']	[]
...fuzz_sax	['fuzz_sax']	[]
lxml.includes.libxml	[]	[]
tempfile	[]	[]
os	[]	[]
lxml.includes.libexslt	[]	[]
...fuzz_xslt	['fuzz_xslt']	[]
lxml.pyclasslookup	[]	[]
urllib2	[]	[]
lxml.builder	[]	[]
lxml.sax	['fuzz_sax']	[]
cssselect	[]	[]
collections	[]	[]
lxml.includes.extlibs	[]	[]
lxml	[]	[]
lxml.html._html5builder	[]	[]
lxml.html._diffcommand	[]	[]
lxml._elementpath	[]	[]
...fuzz_xml_parse	['fuzz_xml_parse']	[]
doctest	[]	[]
etree	[]	[]
optparse	[]	[]
urlparse	[]	[]
lxml.html.soupparser	[]	[]
...fuzz_schematron	['fuzz_schematron']	[]
	[]	[]
lxml.ElementInclude	[]	[]
sys	[]	[]
html	[]	[]
webbrowser	[]	[]
lxml.html._setmixin	[]	[]
lxml.html.clean	[]	[]
lxml.html.builder	[]	[]
lxml.html.formfill	[]	[]
lxml.html.html5parser	[]	[]
...fuzz_xmlschema	['fuzz_xmlschema']	[]
re	[]	[]
lxml.html.defs	[]	[]
lxml.html.diff	[]	[]
bs4	[]	[]
io	[]	[]
difflib	[]	[]
lxml.html.usedoctest	[]	[]
lxml.usedoctest	[]	[]
test_utils	[]	[]
lxml.includes.libxslt	[]	[]
...fuzz_html_parse	['fuzz_html_parse']	[]
lxml.cssselect	[]	[]
lxml.doctestcompare	[]	[]
xml	[]	[]
atheris	[]	[]
cgi	[]	[]
lxml.includes	[]	[]
html5lib	[]	[]
lxml.html.ElementSoup	[]	[]
BeautifulSoup	[]	[]
urllib	[]	[]
lxml.html	[]	[]
functools	[]	[]

Directories in report

Directory