Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues

Fuzzer details

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 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_alloc_pcap_t call site: 00000 /src/libpcap/pcap.c:2496
17 17 2 :

['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 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_check_header call site: 00000 /src/libpcap/sf-pcap.c:258
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:534
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:688
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:719
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:771
17 17 2 :

['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 :

['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 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 read_bytes call site: 00000 /src/libpcap/sf-pcapng.c:263
2 2 1 :

['__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 :

['gen_vlan_bpf_extensions']

335 335 gen_vlan call site: 01578 /src/libpcap/gencode.c:9267
85 85 8 :

['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 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 56 pcap_compile call site: 00046 /src/libpcap/gencode.c:799
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_alloc_pcap_t call site: 00000 /src/libpcap/pcap.c:2496
17 17 2 :

['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 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_check_header call site: 00000 /src/libpcap/sf-pcap.c:258
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:534
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:688
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:719
17 17 2 :

['pcapint_fmt_errmsg_for_errno', '__errno_location']

17 17 pcap_next_packet call site: 00000 /src/libpcap/sf-pcap.c:771
17 17 2 :

['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 :

['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

Analyses and suggestions

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
74.0%
399 / 541
Cyclomatic complexity statically reachable by fuzzers
85.0%
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

Files and Directories in report

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/