High level conclusions

Fuzzers reach 94.35% of cyclomatic complexity.

Fuzzers reach 90.06% of all functions.

Fuzzers reach 81.62% code coverage.

Reachability and coverage overview

Functions statically reachable by fuzzers

299 / 332

Cyclomatic complexity statically reachable by fuzzers

3124 / 3311

Runtime code coverage of functions

271 / 332

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: magic_fuzzer_loaddb

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	157	29.3%
gold	[1:9]	1	0.18%
yellow	[10:29]	1	0.18%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	376	70.2%
All colors	535	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
33	470	apprentice_map	call site: 00470	check_buffer
15	98	apprentice_load	call site: 00098	load_1
10	58	file_apprentice	call site: 00058	get_default_magic
10	508	add_mlist	call site: 00508	apprentice_list
6	429	apprentice_magic_strength_1	call site: 00429	fprintf
5	414	set_test_type	call site: 00414	fprintf
4	72	file_apprentice	call site: 00072	file_oomem
4	79	mlist_free_one	call site: 00079	file_regfree
3	9	fuzzer_get_tmpfile(unsigned char const*, unsigned long)	call site: 00009	perror
3	13	fuzzer_get_tmpfile(unsigned char const*, unsigned long)	call site: 00013	close
3	42	file_checkfmt	call site: 00042	file_error
3	49	file_vprintf	call site: 00049	file_error

Runtime coverage analysis

Covered functions

101

Functions that are reachable but not covered

78

Reachable functions

178

Percentage of reachable functions covered

56.18%

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
/src/magic_fuzzer_loaddb.cc	1
/src/fuzzer_temp_file.h	5
/src/file/src/magic.c	7
/src/file/src/apprentice.c	53
/src/file/src/funcs.c	22
/src/file/src/./file.h	1
/src/file/src/print.c	9
/usr/include/x86_64-linux-gnu/bits/byteswap.h	3
/src/file/src/../src/missing/strlcpy.c	1
/src/file/src/cdf_time.c	4
/src/file/src/encoding.c	1

Fuzzer: magic_fuzzer

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	692	53.9%
gold	[1:9]	11	0.85%
yellow	[10:29]	15	1.17%
greenyellow	[30:49]	20	1.56%
lawngreen	50+	544	42.4%
All colors	1282	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
170	577	file_printable	call site: 00577	doshn
136	440	file_buffer	call site: 00440	file_tryelf
46	766	mcopy	call site: 00766	file_mdump
34	359	cdf_read_property_info	call site: 00359	cdf_file_property_info
27	331	cdf_read_property_info	call site: 00331	cdf_get_property_info_pos
26	1011	magiccheck	call site: 01011	file_magic_strength
25	398	cdf_timestamp_to_timespec	call site: 00398	cdf_file_catalog_info
16	819	file_fmtdatetime	call site: 00819	file_fmtdatetime
12	260	cdf_read_dir	call site: 00260	cdf_swap_dir
12	953	check_regex	call site: 00953	file_magwarn
11	840	file_fmttime	call site: 00840	file_fmtnum
8	101	writechild	call site: 00101	swrite

Runtime coverage analysis

Covered functions

187

Functions that are reachable but not covered

131

Reachable functions

298

Percentage of reachable functions covered

56.04%

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
/src/magic_fuzzer.cc	1
/src/file/src/magic.c	1
/src/file/src/funcs.c	35
/src/file/src/buffer.c	3
/src/file/src/encoding.c	10
/src/file/src/compress.c	16
/src/file/src/is_tar.c	3
/src/file/src/is_json.c	11
/src/file/src/is_csv.c	3
/src/file/src/is_simh.c	4
/src/file/src/readcdf.c	9
/src/file/src/cdf.c	40
/usr/include/x86_64-linux-gnu/bits/byteswap.h	3
/src/file/src/cdf_time.c	5
/src/file/src/readelf.c	21
/src/file/src/../src/missing/strlcpy.c	1
/src/file/src/softmagic.c	30
/src/file/src/apprentice.c	10
/src/file/src/print.c	9
/src/file/src/der.c	6
/src/file/src/../src/missing/fmtcheck.c	4
/src/file/src/ascmagic.c	4

Fuzzer: magic_fuzzer_fd

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	526	38.1%
gold	[1:9]	41	2.97%
yellow	[10:29]	41	2.97%
greenyellow	[30:49]	16	1.16%
lawngreen	50+	754	54.7%
All colors	1378	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
49	52	file_or_fd	call site: 00052	magic_file
46	844	mcopy	call site: 00844	file_mdump
34	438	cdf_read_property_info	call site: 00438	cdf_file_property_info
34	521	file_tryelf	call site: 00521	file_pipe2file
27	410	cdf_read_property_info	call site: 00410	cdf_get_property_info_pos
26	1089	magiccheck	call site: 01089	file_magic_strength
24	477	cdf_timestamp_to_timespec	call site: 00477	cdf_file_catalog_info
16	897	file_fmtdatetime	call site: 00897	file_fmtdatetime
12	183	uncompressbuf	call site: 00183	writechild
12	339	cdf_read_dir	call site: 00339	cdf_swap_dir
12	1031	check_regex	call site: 01031	file_magwarn
11	918	file_fmttime	call site: 00918	file_fmtnum

Runtime coverage analysis

Covered functions

218

Functions that are reachable but not covered

128

Reachable functions

331

Percentage of reachable functions covered

61.33%

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
/src/magic_fuzzer_fd.cc	1
/src/fuzzer_temp_file.h	5
/src/file/src/magic.c	5
/src/file/src/funcs.c	35
/src/file/src/fsmagic.c	4
/src/file/src/compress.c	16
/src/file/src/buffer.c	3
/src/file/src/encoding.c	10
/src/file/src/is_tar.c	3
/src/file/src/is_json.c	11
/src/file/src/is_csv.c	3
/src/file/src/is_simh.c	4
/src/file/src/readcdf.c	9
/src/file/src/cdf.c	40
/usr/include/x86_64-linux-gnu/bits/byteswap.h	3
/src/file/src/cdf_time.c	5
/src/file/src/readelf.c	21
/src/file/src/../src/missing/strlcpy.c	1
/src/file/src/softmagic.c	30
/src/file/src/apprentice.c	10
/src/file/src/print.c	9
/src/file/src/der.c	6
/src/file/src/../src/missing/fmtcheck.c	4
/src/file/src/ascmagic.c	4

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

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

Functions statically reachable by fuzzers

299 / 332

Cyclomatic complexity statically reachable by fuzzers

3124 / 3311

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.

/src/magic_fuzzer_loaddb.cc

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=['apprentice_map', 'apprentice_load', 'file_apprentice', 'add_mlist', 'apprentice_magic_strength_1', 'set_test_type', 'mlist_free_one', 'fuzzer_get_tmpfile(unsigned char const*, unsigned long)', 'fuzzer_get_tmpfile(unsigned char const*, unsigned long)']

/src/magic_fuzzer.cc

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=['file_printable', 'file_buffer', 'mcopy', 'cdf_read_property_info', 'magiccheck', 'cdf_timestamp_to_timespec', 'file_fmtdatetime', 'cdf_read_dir', 'check_regex']

/src/magic_fuzzer_fd.cc

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=['file_or_fd', 'mcopy', 'cdf_read_property_info', 'file_tryelf', 'magiccheck', 'cdf_timestamp_to_timespec', 'file_fmtdatetime', 'uncompressbuf', 'cdf_read_dir']

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
apprentice_load	107	50	46.72%	['magic_fuzzer_loaddb']
check_buffer	62	30	48.38%	['magic_fuzzer', 'magic_fuzzer_loaddb', 'magic_fuzzer_fd']
cdf_read_property_info	144	21	14.58%	['magic_fuzzer', 'magic_fuzzer_fd']
sread	52	27	51.92%	['magic_fuzzer', 'magic_fuzzer_fd']
get_next_format_from_precision	81	40	49.38%	['magic_fuzzer', 'magic_fuzzer_fd']
cdf_check_summary_info	39	10	25.64%	['magic_fuzzer', 'magic_fuzzer_fd']
cdf_file_summary_info	48	7	14.58%	['magic_fuzzer', 'magic_fuzzer_fd']
cvt_flip	56	28	50.0%	['magic_fuzzer', 'magic_fuzzer_fd']
handle_annotation	36	6	16.66%	['magic_fuzzer', 'magic_fuzzer_fd']
file_fsmagic	171	12	7.017%	['magic_fuzzer_fd']
file_or_fd	83	43	51.80%	['magic_fuzzer_fd']

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/magic_fuzzer_fd.cc	['magic_fuzzer_fd']	['magic_fuzzer_fd']
/src/file/src/is_simh.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/usr/include/x86_64-linux-gnu/bits/byteswap.h	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	[]
/src/file/src/magic.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/is_tar.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/readcdf.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/magic_fuzzer_loaddb.cc	['magic_fuzzer_loaddb']	['magic_fuzzer_loaddb']
/src/file/src/cdf_time.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/compress.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/../src/missing/fmtcheck.c	['magic_fuzzer', 'magic_fuzzer_fd']	[]
/src/file/src/ascmagic.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/buffer.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/is_json.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/fsmagic.c	['magic_fuzzer_fd']	['magic_fuzzer_fd']
/src/file/src/../src/missing/strlcpy.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	[]
/src/file/src/readelf.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_fd']
/src/file/src/softmagic.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/is_csv.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/magic_fuzzer.cc	['magic_fuzzer']	['magic_fuzzer']
/usr/local/bin/../include/c++/v1/stdexcept	[]	[]
/src/file/src/print.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/./file.h	['magic_fuzzer_loaddb']	[]
/src/file/src/encoding.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/fuzzer_temp_file.h	['magic_fuzzer_loaddb', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer_fd']
/src/file/src/der.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/funcs.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/cdf.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/apprentice.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']

Directories in report

Directory
/src/
/usr/local/bin/../include/c++/v1/
/src/file/src/../src/missing/
/src/file/src/./
/usr/include/x86_64-linux-gnu/bits/
/src/file/src/