High level conclusions

Fuzzer fuzz_mime is blocked:

The runtime code coverage of fuzz_mime covers 22.22% 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_menu is blocked:

The runtime code coverage of fuzz_menu covers 2.747% 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_desktop_entry is blocked:

The runtime code coverage of fuzz_desktop_entry covers 8.474% 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_icon is blocked:

The runtime code coverage of fuzz_icon covers 11.59% 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

105 / 538

Cyclomatic complexity statically reachable by fuzzers

444 / 1975

Runtime code coverage of functions

51 / 538

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_icon

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	159	84.1%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	30	15.8%
All colors	189	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
141	36	...fuzz_icon.TestOneInput	call site: 00036	xdg.DesktopEntry.DesktopEntry.checkKey
7	181	...fuzz_icon.TestOneInput	call site: 00181	xdg.IconTheme.IconData.__init__
6	28	xdg.IconTheme.IconTheme.parse	call site: 00028	xdg.IconTheme.IconTheme.parse
3	7	xdg.IniFile.IniFile.__init__	call site: 00007	xdg.IconTheme.IconData.parse
1	3	...fuzz_icon.TestOneInput	call site: 00003	f.write
1	19	xdg.IniFile.IniFile.parse	call site: 00019	xdg.DesktopEntry.DesktopEntry.parse

Runtime coverage analysis

Covered functions

58

Functions that are reachable but not covered

61

Reachable functions

69

Percentage of reachable functions covered

11.59%

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_icon	10
xdg.IconTheme	16
xdg.IniFile	45
xdg.DesktopEntry	15

Fuzzer: fuzz_desktop_entry

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	115	79.3%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	30	20.6%
All colors	145	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
82	61	...fuzz_desktop_entry.TestOneInput	call site: 00061	xdg.IniFile.IniFile.checkValue
26	31	xdg.DesktopEntry.DesktopEntry.parse	call site: 00031	xdg.DesktopEntry.DesktopEntry.new
6	24	xdg.IconTheme.IconTheme.parse	call site: 00024	xdg.DesktopEntry.DesktopEntry.parse
1	7	xdg.DesktopEntry.DesktopEntry.__init__	call site: 00007	xdg.DesktopEntry.DesktopEntry.parse

Runtime coverage analysis

Covered functions

58

Functions that are reachable but not covered

54

Reachable functions

59

Percentage of reachable functions covered

8.47%

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_desktop_entry	9
xdg.DesktopEntry	20
xdg.IniFile	31
xdg.IconTheme	6

Fuzzer: fuzz_menu

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	332	93.5%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	23	6.47%
All colors	355	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
165	3	...fuzz_menu.TestOneInput	call site: 00003	xdg.Menu.parse
160	194	xdg.DesktopEntry.DesktopEntry.parse	call site: 00194	xdg.Menu.XMLMenuBuilder.parse_kde_legacy_dirs
6	185	xdg.IconTheme.IconTheme.parse	call site: 00185	xdg.IconTheme.IconTheme.parse
1	170	xdg.DesktopEntry.DesktopEntry.__init__	call site: 00170	xdg.DesktopEntry.DesktopEntry.parse

Runtime coverage analysis

Covered functions

58

Functions that are reachable but not covered

177

Reachable functions

182

Percentage of reachable functions covered

2.75%

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_menu	7
xdg.Menu	147
xdg.DesktopEntry	11
xdg.IconTheme	6
xdg.IniFile	22

Fuzzer: fuzz_mime

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	64	49.6%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	65	50.3%
All colors	129	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
35	45	xdg.Mime.MagicDB.merge_file	call site: 00045	xdg.Mime.MagicMatchAny.from_file
7	94	xdg.Mime.get_type2	call site: 00094	xdg.Mime._get_type_by_stat
6	31	xdg.Mime.GlobDB.finalise	call site: 00031	mtype.canonical
3	90	xdg.Mime.get_type2	call site: 00090	xdg.Mime.get_type_by_name
2	13	xdg.BaseDirectory.load_data_paths	call site: 00013	.open
2	82	xdg.Mime.MagicDB.finalise	call site: 00082	rule.maxlen
2	86	xdg.Mime._cache_database	call site: 00086	.open
2	126	...fuzz_mime.TestOneInput	call site: 00126	.str
1	19	xdg.Mime._cache_database	call site: 00019	xdg.Mime.GlobDB.merge_file
1	41	xdg.Mime._cache_database	call site: 00041	xdg.Mime.MagicDB.merge_file
1	103	xdg.Mime.get_type2	call site: 00103	.len
1	111	xdg.Mime._is_text	call site: 00111	.any

Runtime coverage analysis

Covered functions

57

Functions that are reachable but not covered

56

Reachable functions

72

Percentage of reachable functions covered

22.22%

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_mime	14
xdg.Mime	63
xdg.BaseDirectory	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
lxml.doctestcompare.LXMLOutputChecker.output_difference	lxml.doctestcompare	4	['N/A', 'N/A', 'N/A', 'N/A']	5	0	3	3	4	47	0	160	142
lxml.html._MethodFunc.__call__	lxml.html	4	['N/A', 'N/A', 'N/A', 'N/A']	3	0	0	5	5	28	0	100	94
xdg.MenuEditor.MenuEditor.__addEntry	xdg.MenuEditor	5	['N/A', 'N/A', 'N/A', 'N/A', 'N/A']	2	0	8	6	5	25	7	86	77
lxml.html.HtmlMixin.rewrite_links	lxml.html	4	['N/A', 'N/A', 'N/A', 'N/A']	9	0	4	7	6	24	3	90	74
lxml.ElementInclude.include	lxml.ElementInclude	4	['N/A', 'N/A', 'N/A', 'N/A']	3	0	1	6	5	23	0	81	69
xdg.IconTheme.getIconPath	xdg.IconTheme	4	['N/A', 'N/A', 'N/A', 'N/A']	9	0	1	11	7	53	1	191	67
lxml.html.soupparser._parse	lxml.html.soupparser	4	['N/A', 'N/A', 'N/A', 'N/A']	4	0	0	6	5	23	3	78	63
lxml.html.formfill._fill_form	lxml.html.formfill	2	['N/A', 'N/A']	3	0	2	7	6	18	2	66	47
lxml.html._diffcommand.main	lxml.html._diffcommand	1	['N/A']	2	0	5	5	5	19	0	64	46
xdg.MenuEditor.MenuEditor.__saveEntries	xdg.MenuEditor	2	['N/A', 'N/A']	4	0	3	4	5	16	2	59	44

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

Functions statically reachable by fuzzers

176 / 538

Cyclomatic complexity statically reachable by fuzzers

750 / 1975

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_icon.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_icon.TestOneInput', 'xdg.IconTheme.IconTheme.parse', 'xdg.IniFile.IniFile.__init__', 'xdg.IniFile.IniFile.parse']

/src/fuzz_desktop_entry.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_desktop_entry.TestOneInput', 'xdg.DesktopEntry.DesktopEntry.parse', 'xdg.IconTheme.IconTheme.parse', 'xdg.DesktopEntry.DesktopEntry.__init__']

/src/fuzz_menu.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_menu.TestOneInput', 'xdg.DesktopEntry.DesktopEntry.parse', 'xdg.IconTheme.IconTheme.parse', 'xdg.DesktopEntry.DesktopEntry.__init__']

/src/fuzz_mime.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=['xdg.Mime.MagicDB.merge_file', 'xdg.Mime.get_type2', 'xdg.Mime.GlobDB.finalise', 'xdg.BaseDirectory.load_data_paths', 'xdg.Mime.MagicDB.finalise', 'xdg.Mime._cache_database', '...fuzz_mime.TestOneInput']

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
xdg.IconTheme.IconTheme.checkKey	45	1	2.222%	['fuzz_icon']
xdg.IconTheme.getIconPath	41	0	0.0%	[]
xdg.IniFile.IniFile.get	38	0	0.0%	['fuzz_icon', 'fuzz_desktop_entry', 'fuzz_menu']
xdg.DesktopEntry.DesktopEntry.checkKey	137	0	0.0%	['fuzz_icon', 'fuzz_desktop_entry']
xdg.Locale._expand_lang	32	0	0.0%	[]
xdg.Mime.get_type2	31	13	41.93%	['fuzz_mime']

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.objectify	[]	[]
tempfile	[]	[]
lxml.html.formfill	[]	[]
	[]	[]
lxml.html.ElementSoup	[]	[]
lxml.html._html5builder	[]	[]
atheris	[]	[]
webbrowser	[]	[]
lxml.html.usedoctest	[]	[]
xml	[]	[]
os	[]	[]
xdg.Exceptions	[]	[]
lxml.etree	[]	[]
cgi	[]	[]
xdg.util	[]	[]
locale	[]	[]
xdg.Menu	['fuzz_menu']	[]
xdg	[]	[]
lxml.html	[]	[]
lxml.html.diff	[]	[]
...fuzz_desktop_entry	['fuzz_desktop_entry']	[]
io	[]	[]
functools	[]	[]
bs4	[]	[]
lxml.ElementInclude	[]	[]
lxml.html._diffcommand	[]	[]
lxml.sax	[]	[]
xdg.Config	[]	[]
imp	[]	[]
xdg.RecentFiles	[]	[]
ast	[]	[]
urllib	[]	[]
fnmatch	[]	[]
cssselect	[]	[]
warnings	[]	[]
lxml.html._setmixin	[]	[]
xdg.IconTheme	['fuzz_icon', 'fuzz_desktop_entry', 'fuzz_menu']	[]
BeautifulSoup	[]	[]
urlparse	[]	[]
lxml.builder	[]	[]
lxml.html.defs	[]	[]
getpass	[]	[]
xdg.IniFile	['fuzz_icon', 'fuzz_desktop_entry', 'fuzz_menu']	[]
lxml.usedoctest	[]	[]
lxml.isoschematron	[]	[]
xdg.Locale	[]	[]
html	[]	[]
fcntl	[]	[]
html5lib	[]	[]
lxml	[]	[]
lxml.html.soupparser	[]	[]
lxml.doctestcompare	[]	[]
subprocess	[]	[]
...fuzz_mime	['fuzz_mime']	[]
optparse	[]	[]
re	[]	[]
lxml.html.clean	[]	[]
lxml.html.html5parser	[]	[]
urllib2	[]	[]
lxml.includes	[]	[]
stat	[]	[]
pkg_resources	[]	[]
xdg.MenuEditor	[]	[]
...fuzz_menu	['fuzz_menu']	[]
collections	[]	[]
doctest	[]	[]
time	[]	[]
lxml.html.builder	[]	[]
lxml.pyclasslookup	[]	[]
xdg.Mime	['fuzz_mime']	[]
...fuzz_icon	['fuzz_icon']	[]
lxml.cssselect	[]	[]
shutil	[]	[]
lxml._elementpath	[]	[]
xdg.BaseDirectory	['fuzz_mime']	[]
sys	[]	[]
xdg.DesktopEntry	['fuzz_icon', 'fuzz_desktop_entry', 'fuzz_menu']	[]

Directories in report

Directory