High level conclusions

Fuzzers reach 55.93% of cyclomatic complexity.

Fuzzers reach 51.57% of all functions.

Fuzzer fuzz_pcap is blocked:

The runtime code coverage of fuzz_pcap covers 27.77% 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

279 / 541

Cyclomatic complexity statically reachable by fuzzers

2070 / 3701

Runtime code coverage of functions

270 / 541

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	2141	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	2141	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
2140	0	EP	call site: 00000	pcap_compile

Runtime coverage analysis

Covered functions

0

Functions that are reachable but not covered

298

Reachable functions

298

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	11
gencode.c	162
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	26	46.4%
gold	[1:9]	3	5.35%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	27	48.2%
All colors	56	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
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_alloc_pcap_t	call site: 00000	/src/libpcap/pcap.c:2496
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_fopen_offline_with_tstamp_precision	call site: 00031	/src/libpcap/savefile.c:504
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_check_header	call site: 00000	/src/libpcap/sf-pcap.c:258
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:534
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:688
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:719
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:771
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:820
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:835
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	read_bytes	call site: 00000	/src/libpcap/sf-pcapng.c:263
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	42	144	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:679

Runtime coverage analysis

Covered functions

45

Functions that are reachable but not covered

26

Reachable functions

36

Percentage of reachable functions covered

27.78%

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
build/../testprogs/fuzz/fuzz_pcap.c	2
savefile.c	4
fmtutils.c	2
pcap.c	4
bpf_filter.c	2
extract.h	2

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	639	29.2%
gold	[1:9]	259	11.8%
yellow	[10:29]	82	3.75%
greenyellow	[30:49]	56	2.56%
lawngreen	50+	1146	52.5%
All colors	2182	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
335	335	1 : View List ['gen_vlan_bpf_extensions']	335	335	gen_vlan	call site: 01578	/src/libpcap/gencode.c:9267
85	85	8 : View List ['pcap_realloc', 'pcap_restart', 'yy_fatal_error', 'ferror', 'getc', 'fread', '__errno_location', 'clearerr']	85	85	yy_get_next_buffer	call site: 00121	/src/libpcap/build/scanner.c:4647
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	56	pcap_compile	call site: 00046	/src/libpcap/gencode.c:799
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_alloc_pcap_t	call site: 00000	/src/libpcap/pcap.c:2496
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_fopen_offline_with_tstamp_precision	call site: 00031	/src/libpcap/savefile.c:504
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_check_header	call site: 00000	/src/libpcap/sf-pcap.c:258
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:534
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:688
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:719
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_next_packet	call site: 00000	/src/libpcap/sf-pcap.c:771
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:820
17	17	2 : View List ['pcapint_fmt_errmsg_for_errno', '__errno_location']	17	17	pcap_ng_check_header	call site: 00000	/src/libpcap/sf-pcapng.c:835

Runtime coverage analysis

Covered functions

271

Functions that are reachable but not covered

74

Reachable functions

310

Percentage of reachable functions covered

76.13%

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	4
fmtutils.c	2
pcap.c	9
gencode.c	162
build/scanner.c	24
build/grammar.c	2
missing/strlcpy.c	1
scanner.l	2
nametoaddr.c	11
extract.h	2
build/grammar.y	4
optimize.c	47
bpf_filter.c	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
pcap_findalldevs_ex	/src/libpcap/pcap.c	4	['N/A', 'N/A', 'N/A', 'N/A']	9	0	474	60	23	61	0	327	263
pcap_activate_linux	/src/libpcap/pcap-linux.c	1	['N/A']	8	0	351	45	15	56	0	291	244
pcap_ng_next_packet	/src/libpcap/sf-pcapng.c	3	['N/A', 'N/A', 'N/A']	6	0	1009	70	19	35	0	208	181
pcap_open	/src/libpcap/pcap.c	6	['N/A', 'int', 'int', 'int', 'N/A', 'N/A']	8	0	265	46	16	47	0	243	97
pcap_read_linux_mmap_v3	/src/libpcap/pcap-linux.c	4	['N/A', 'int', 'N/A', 'N/A']	6	0	533	77	28	27	0	166	92
netfilter_activate	/src/libpcap/pcap-netfilter-linux.c	1	['N/A']	4	0	626	89	35	27	0	117	77
pcap_setfilter_linux	/src/libpcap/pcap-linux.c	2	['N/A', 'N/A']	5	0	352	65	21	21	0	103	72
pcap_dump_open_append	/src/libpcap/sf-pcap.c	2	['N/A', 'N/A']	4	0	430	60	20	18	0	72	45
netfilter_read_linux	/src/libpcap/pcap-netfilter-linux.c	4	['N/A', 'int', 'N/A', 'N/A']	4	0	766	115	38	24	0	133	42
pcap_check_header	/src/libpcap/sf-pcap.c	5	['N/A', 'N/A', 'int', 'N/A', 'N/A']	6	0	644	77	25	16	0	72	36

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

Functions statically reachable by fuzzers

399 / 541

Cyclomatic complexity statically reachable by fuzzers

3145 / 3701

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_mtp2type_abbrev', 'gen_scode', 'gen_atmmulti_abbrev', 'gen_loadi_internal', 'sdup', 'gen_vlan_vid_test', 'gen_mcode', 'pcap_lex']

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

Directories in report

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