High level conclusions

Fuzzer fuzz_fragroute is blocked:

The runtime code coverage of fuzz_fragroute 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_services is blocked:

The runtime code coverage of fuzz_services covers 13.63% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Fuzzers reach 5.559% of cyclomatic complexity.

Fuzzers reach 6.187% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

43 / 695

Cyclomatic complexity statically reachable by fuzzers

255 / 4587

Runtime code coverage of functions

48 / 695

Warning: The number of runtime covered functions are larger than the number of reachable functions. This means that Fuzz Introspector found there are more functions covered at runtime than what is considered reachable based on the static analysis. This is a limitation in the analysis as anything covered at runtime is by definition reachable by the fuzzers.
This is likely due to a limitation in the static analysis. In this case, the count of functions covered at runtime is the true value, which means this is what should be considered "achieved" by the fuzzer.

Use the project functions table below to query all functions that were not covered at runtime.

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_services

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	9	30.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	21	70.0%
All colors	30	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
5	9	parse_services	call site: 00009	__errno_location
3	15	parse_services	call site: 00015	fprintf
1	4	fuzz_write_tempfile	call site: 00004	unlink

Runtime coverage analysis

Covered functions

3

Functions that are reachable but not covered

19

Reachable functions

22

Percentage of reachable functions covered

13.64%

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
tcpreplay/test/fuzz/fuzz_services.c	1
tcpreplay/test/fuzz/fuzz_common.h	1
tcpreplaycommon/services.c	1

Fuzzer: fuzz_fragroute

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	140	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	140	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
139	0	EP	call site: 00000	fragroute_process

Runtime coverage analysis

Covered functions

0

Functions that are reachable but not covered

48

Reachable functions

48

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
tcpreplay/test/fuzz/fuzz_fragroute.c	1
tcpreplay/test/fuzz/fuzz_common.h	2
tcpreplayfragroute/fragroute.c	4
tcpreplaycommon/utils.c	1
tcpreplayfragroute/pkt.c	4
tcpreplayfragroute/bget.c	4
tcpreplayfragroute/mod.c	2
tcpreplayfragroute/argv.c	1
tcpreplaycommon/get.c	5
libpcap/pcap.c	1

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	25.4%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	1	0.90%
lawngreen	50+	81	73.6%
All colors	110	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	5	pcap_fopen_offline_with_tstamp_precision	call site: 00005	pcapint_fmt_errmsg_for_errno
8	22	pcapint_offline_read	call site: 00022	pcapint_filter_with_aux_data
4	87	get_l2len_protocol	call site: 00087	pcap_datalink_val_to_description
3	55	parse_metadata	call site: 00055	fprintf
2	35	get_l2len_protocol	call site: 00035	fprintf
1	3	pcap_fopen_offline	call site: 00003	snprintf

Runtime coverage analysis

Covered functions

47

Functions that are reachable but not covered

24

Reachable functions

42

Percentage of reachable functions covered

42.86%

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
tcpreplay/test/fuzz/fuzz_pcap.c	1
libpcap/savefile.c	3
libpcap/fmtutils.c	2
libpcap/pcap.c	5
libpcap/bpf_filter.c	2
libpcap/extract.h	2
tcpreplaycommon/get.c	9

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_compile_nopcap	/src/libpcap/gencode.c	6	['int', 'int', 'N/A', 'N/A', 'int', 'int']	18	0	54	6	3	344	0	2358	2309
pcap_activate_linux	/src/libpcap/pcap-linux.c	1	['N/A']	8	0	343	45	15	56	0	293	261
pcap_ng_next_packet	/src/libpcap/sf-pcapng.c	3	['N/A', 'N/A', 'N/A']	6	0	992	70	19	37	0	213	186
pcap_lookupdev	/src/libpcap/pcap.c	1	['N/A']	9	0	74	14	6	41	0	185	137
pcap_read_linux_mmap_v3	/src/libpcap/pcap-linux.c	4	['N/A', 'int', 'N/A', 'N/A']	6	0	522	77	28	27	0	166	92
pcap_open_live	/src/libpcap/pcap.c	5	['N/A', 'int', 'int', 'int', 'N/A']	8	0	183	29	12	30	0	136	90
print_apply	/src/tcpreplay/src/fragroute/mod_print.c	2	['N/A', 'N/A']	3	0	142	19	7	22	0	96	86
netfilter_activate	/src/libpcap/pcap-netfilter-linux.c	1	['N/A']	5	0	598	89	35	28	0	119	78
pcap_setfilter_linux	/src/libpcap/pcap-linux.c	2	['N/A', 'N/A']	5	0	344	65	21	22	0	105	74
ip_frag_apply	/src/tcpreplay/src/fragroute/mod_ip_frag.c	2	['N/A', 'N/A']	5	0	69	12	5	13	0	96	63

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

Functions statically reachable by fuzzers

474 / 695

Cyclomatic complexity statically reachable by fuzzers

3527 / 4587

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.

tcpreplay/test/fuzz/fuzz_services.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=['parse_services', 'fuzz_write_tempfile']

tcpreplay/test/fuzz/fuzz_fragroute.c

Dictionary

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

tcpreplay/test/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_fopen_offline_with_tstamp_precision', 'pcapint_offline_read', 'get_l2len_protocol', 'parse_metadata', 'pcap_fopen_offline']

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
swap_pflog_header	39	9	23.07%	['fuzz_pcap']
swap_linux_usb_header	84	6	7.142%	['fuzz_pcap']
swap_nflog_header	35	11	31.42%	['fuzz_pcap']

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/pcap-linux.c	[]	[]
/src/tcpreplay/src/fragroute/mod_order.c	[]	[]
/src/libpcap/build/scanner.c	[]	[]
/src/tcpreplay/src/fragroute/mod_tcp_opt.c	[]	[]
/src/tcpreplay/test/fuzz/fuzz_pcap.c	['fuzz_pcap']	['fuzz_pcap']
/src/libpcap/optimize.c	[]	[]
/src/tcpreplay/src/fragroute/mod_delay.c	[]	[]
/src/tcpreplay/test/fuzz/fuzz_services.c	['fuzz_services']	['fuzz_services']
/src/libpcap/sf-pcapng.c	[]	[]
/src/tcpreplay/src/fragroute/pkt.c	['fuzz_fragroute']	[]
/src/libpcap/sf-pcap.c	[]	[]
/src/libpcap/gencode.c	[]	[]
/src/tcpreplay/src/fragroute/mod_ip_chaff.c	[]	[]
/src/tcpreplay/src/fragroute/mod_ip_frag.c	[]	[]
/src/tcpreplay/src/fragroute/mod_drop.c	[]	[]
/src/tcpreplay/src/fragroute/bget.c	['fuzz_fragroute']	[]
/src/libpcap/pcap.c	['fuzz_fragroute', 'fuzz_pcap']	['fuzz_pcap']
/src/libpcap/pcap-usb-linux-common.h	[]	[]
/src/tcpreplay/src/fragroute/mod_echo.c	[]	[]
/src/libpcap/build/grammar.y	[]	[]
/src/libpcap/fmtutils.c	['fuzz_pcap']	[]
/src/libpcap/fad-getad.c	[]	[]
/src/tcpreplay/src/fragroute/fragroute.c	['fuzz_fragroute']	[]
/src/tcpreplay/src/common/services.c	['fuzz_services']	['fuzz_services']
/src/libpcap/pcap-netfilter-linux.c	[]	[]
/src/tcpreplay/src/fragroute/mod_ip_tos.c	[]	[]
/src/libpcap/scanner.l	[]	[]
/src/libpcap/extract.h	['fuzz_pcap']	['fuzz_pcap']
/src/libpcap/bpf_filter.c	['fuzz_pcap']	[]
/src/tcpreplay/src/fragroute/randutil.c	[]	[]
/src/libpcap/pcap-util.c	[]	[]
/src/libpcap/missing/strlcpy.c	[]	[]
/src/tcpreplay/src/fragroute/mod_ip6_opt.c	[]	[]
/src/libpcap/savefile.c	['fuzz_pcap']	['fuzz_pcap']
/src/tcpreplay/src/fragroute/mod_tcp_seg.c	[]	[]
/src/tcpreplay/src/fragroute/iputil.c	[]	[]
/src/libpcap/build/grammar.c	[]	[]
/src/tcpreplay/src/fragroute/mod_ip_opt.c	[]	[]
/src/tcpreplay/test/fuzz/fuzz_fragroute.c	['fuzz_fragroute']	[]
/src/tcpreplay/src/fragroute/argv.c	['fuzz_fragroute']	[]
/src/tcpreplay/src/fragroute/mod_tcp_chaff.c	[]	[]
/src/libpcap/nametoaddr.c	[]	[]
/src/tcpreplay/src/common/utils.c	['fuzz_fragroute']	[]
/src/tcpreplay/src/fragroute/mod_ip_ttl.c	[]	[]
/src/tcpreplay/src/fragroute/mod.c	['fuzz_fragroute']	[]
/src/libpcap/pcap-common.c	[]	[]
/src/tcpreplay/test/fuzz/fuzz_common.h	['fuzz_services', 'fuzz_fragroute']	['fuzz_services']
/src/tcpreplay/src/fragroute/mod_print.c	[]	[]
/src/tcpreplay/src/common/get.c	['fuzz_fragroute', 'fuzz_pcap']	['fuzz_pcap']
/src/tcpreplay/src/fragroute/mod_ip6_qos.c	[]	[]
/src/libpcap/pcap-util.h	[]	[]
/src/tcpreplay/src/fragroute/mod_dup.c	[]	[]

Directories in report

Directory
/src/libpcap/build/
/src/tcpreplay/src/fragroute/
/src/tcpreplay/src/common/
/src/libpcap/
/src/tcpreplay/test/fuzz/
/src/libpcap/missing/