High level conclusions

Fuzzers reach 56.72% of cyclomatic complexity.

Fuzzers reach 54.30% of all functions.

Fuzzer fuzz_pcap is blocked:

The runtime code coverage of fuzz_pcap covers 27.90% 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_filter is blocked:

The runtime code coverage of fuzz_filter 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

290 / 534

Cyclomatic complexity statically reachable by fuzzers

2089 / 3683

Runtime code coverage of functions

262 / 534

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_filter

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	2059	100.%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	0	0.0%
All colors	2059	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
2058	0	EP	call site: 00000	pcap_compile

Runtime coverage analysis

Covered functions

0

Functions that are reachable but not covered

302

Reachable functions

302

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
build/../testprogs/fuzz/fuzz_filter.c	1
pcap.c	20
gencode.c	154
build/scanner.c	24
fmtutils.c	2
build/grammar.c	2
missing/strlcpy.c	1
scanner.l	2
nametoaddr.c	11
extract.h	2
build/grammar.y	4
optimize.c	47

Fuzzer: fuzz_pcap

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	28	41.7%
gold	[1:9]	3	4.47%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	36	53.7%
All colors	67	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_alloc_pcap_t	call site: 00000	/src/libpcap/pcap.c:2498
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_fopen_offline_with_tstamp_precision	call site: 00030	/src/libpcap/savefile.c:506
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_check_header	call site: 00000	/src/libpcap/sf-pcap.c:185
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:461
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:615
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:646
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:698
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:822
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:837
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	read_bytes	call site: 00000	/src/libpcap/sf-pcapng.c:265
2	2	1 : View List ['__errno_location']	2	2	bufferToFile	call site: 00009	/src/libpcap/build/../testprogs/fuzz/fuzz_pcap.c:21
0	0	None	38	138	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:606

Runtime coverage analysis

Covered functions

43

Functions that are reachable but not covered

31

Reachable functions

43

Percentage of reachable functions covered

27.91%

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
build/../testprogs/fuzz/fuzz_pcap.c	2
savefile.c	10
fmtutils.c	2
bpf_filter.c	2
extract.h	2
missing/strlcpy.c	1
pcap.c	4

Fuzzer: fuzz_both

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	605	28.9%
gold	[1:9]	255	12.1%
yellow	[10:29]	84	4.01%
greenyellow	[30:49]	71	3.39%
lawngreen	50+	1078	51.5%
All colors	2093	100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity	Unique Reachable Complexities	Unique Reachable Functions	All non-covered Complexity	All Reachable Complexity	Function Name	Function Callsite	Blocked Branch
337	337	1 : View List ['gen_vlan_bpf_extensions']	337	337	gen_vlan	call site: 01552	/src/libpcap/gencode.c:9261
85	85	8 : View List ['pcap_restart', 'fread', 'getc', 'ferror', 'yy_fatal_error', 'clearerr', '__errno_location', 'pcap_realloc']	85	85	yy_get_next_buffer	call site: 00140	/src/libpcap/build/scanner.c:4649
25	25	1 : View List ['gen_geneve_ll_check']	25	25	gen_prevlinkhdr_check	call site: 00366	/src/libpcap/gencode.c:3164
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	54	pcap_compile	call site: 00066	/src/libpcap/gencode.c:800
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_alloc_pcap_t	call site: 00000	/src/libpcap/pcap.c:2498
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_fopen_offline_with_tstamp_precision	call site: 00030	/src/libpcap/savefile.c:506
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_check_header	call site: 00000	/src/libpcap/sf-pcap.c:185
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:461
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:615
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:646
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:698
15	15	2 : View List ['__errno_location', 'pcapint_fmt_errmsg_for_errno']	15	15	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:822

Runtime coverage analysis

Covered functions

263

Functions that are reachable but not covered

80

Reachable functions

311

Percentage of reachable functions covered

74.28%

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
build/../testprogs/fuzz/fuzz_both.c	2
savefile.c	10
fmtutils.c	2
bpf_filter.c	2
extract.h	2
missing/strlcpy.c	1
pcap.c	9
gencode.c	154
build/scanner.c	24
build/grammar.c	2
scanner.l	2
nametoaddr.c	11
build/grammar.y	4
optimize.c	47

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
pcap_open	/src/libpcap/pcap.c	6	['char *', 'int', 'int', 'int', 'struct.pcap_rmtauth *', 'char *']	8	0	265	46	16	148	0	811	676
pcap_ng_check_header	/src/libpcap/sf-pcapng.c	5	['char *', 'struct._IO_FILE *', 'int', 'char *', 'int *']	6	0	678	72	23	41	0	254	219
pcap_findalldevs_ex	/src/libpcap/pcap.c	4	['char *', 'struct.pcap_rmtauth *', 'struct.pcap_if **', 'char *']	9	0	476	60	23	75	0	389	175
netfilter_create	/src/libpcap/pcap-netfilter-linux.c	3	['char *', 'char *', 'int *']	6	0	123	20	8	58	0	250	135
usb_create	/src/libpcap/pcap-usb-linux.c	3	['char *', 'char *', 'int *']	6	0	119	18	8	56	0	216	75
pcap_check_header	/src/libpcap/sf-pcap.c	5	['char *', 'struct._IO_FILE *', 'int', 'char *', 'int *']	6	0	649	77	25	31	0	196	49
pcap_dump_open_append	/src/libpcap/sf-pcap.c	2	['struct.pcap *', 'char *']	3	0	432	60	20	17	0	70	45

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

Functions statically reachable by fuzzers

451 / 534

Cyclomatic complexity statically reachable by fuzzers

3381 / 3683

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.

build/../testprogs/fuzz/fuzz_filter.c

Dictionary

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

build/../testprogs/fuzz/fuzz_pcap.c

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=['pcap_open_offline_with_tstamp_precision', 'pcapint_offline_read', 'bufferToFile', 'pcap_open_offline', 'pcap_fopen_offline_with_tstamp_precision', 'EXTRACT_BE_U_2']

build/../testprogs/fuzz/fuzz_both.c

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=['gen_pppoes', 'gen_port6', 'gen_scode', 'gen_atmmulti_abbrev', 'gen_loadi_internal', 'gen_vlan_vid_test', 'sdup', 'gen_mtp2type_abbrev', 'gen_llc_s_subtype', 'gen_mcode']

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
pcap_open_offline_with_tstamp_precision	32	16	50.0%	['fuzz_pcap', 'fuzz_both']
yy_get_next_buffer	90	19	21.11%	['fuzz_filter', 'fuzz_both']
gen_atmmulti_abbrev	60	26	43.33%	['fuzz_filter', 'fuzz_both']

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
	[]	[]
/src/libpcap/build/scanner.c	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/fmtutils.c	['fuzz_filter', 'fuzz_pcap', 'fuzz_both']	[]
/src/libpcap/sf-pcap.c	[]	[]
/src/libpcap/missing/strlcpy.c	['fuzz_filter', 'fuzz_pcap', 'fuzz_both']	['fuzz_both']
/src/libpcap/build/grammar.y	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/nametoaddr.c	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/extract.h	['fuzz_filter', 'fuzz_pcap', 'fuzz_both']	['fuzz_pcap', 'fuzz_both']
/src/libpcap/fad-getad.c	[]	[]
/src/libpcap/pcap-netfilter-linux.c	[]	[]
/src/libpcap/scanner.l	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/pcap-usb-linux-common.c	[]	[]
/src/libpcap/pcap-util.c	[]	[]
/src/libpcap/missing/strlcat.c	[]	[]
/src/libpcap/build/grammar.c	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/build/../testprogs/fuzz/fuzz_filter.c	['fuzz_filter']	[]
/src/libpcap/gencode.c	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/pcap.c	['fuzz_filter', 'fuzz_pcap', 'fuzz_both']	['fuzz_pcap', 'fuzz_both']
/src/libpcap/bpf_filter.c	['fuzz_pcap', 'fuzz_both']	['fuzz_both']
/src/libpcap/build/../testprogs/fuzz/fuzz_pcap.c	['fuzz_pcap']	[]
/src/libpcap/pcap-usb-linux.c	[]	[]
/src/libpcap/savefile.c	['fuzz_pcap', 'fuzz_both']	['fuzz_pcap', 'fuzz_both']
/src/libpcap/optimize.c	['fuzz_filter', 'fuzz_both']	['fuzz_both']
/src/libpcap/pcap-linux.c	[]	[]
/src/libpcap/build/../testprogs/fuzz/fuzz_both.c	['fuzz_both']	[]
/src/libpcap/sf-pcapng.c	[]	[]
/src/libpcap/pcap-common.c	[]	[]

Directories in report

Directory
/src/libpcap/missing/
/src/libpcap/build/../testprogs/fuzz/
/src/libpcap/
/src/libpcap/build/