High level conclusions

Fuzzers reach 95.05% of cyclomatic complexity.

Fuzzers reach 90.43% of all functions.

Fuzzers reach 85.18% code coverage.

Reachability and coverage overview

Functions statically reachable by fuzzers

293 / 324

Cyclomatic complexity statically reachable by fuzzers

3095 / 3256

Runtime code coverage of functions

276 / 324

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	151	28.9%
gold	[1:9]	1	0.19%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	369	70.8%
All colors	521	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
32	457	apprentice_map	call site: 00457	check_buffer
15	97	apprentice_load	call site: 00097	load_1
10	58	file_apprentice	call site: 00058	get_default_magic
10	494	add_mlist	call site: 00494	apprentice_list
6	417	apprentice_magic_strength_1	call site: 00417	fprintf
5	402	set_test_type	call site: 00402	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

97

Functions that are reachable but not covered

78

Reachable functions

174

Percentage of reachable functions covered

55.17%

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	19
/src/file/src/print.c	9
/src/file/src/strlcpy.c	1
/src/file/src/cdf_time.c	4
/src/file/src/encoding.c	1
/usr/include/x86_64-linux-gnu/bits/byteswap.h	3

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	638	51.2%
gold	[1:9]	22	1.76%
yellow	[10:29]	34	2.72%
greenyellow	[30:49]	22	1.76%
lawngreen	50+	530	42.5%
All colors	1246	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	575	file_printable	call site: 00575	doshn
136	438	file_buffer	call site: 00438	file_tryelf
46	764	mcopy	call site: 00764	file_mdump
26	973	magiccheck	call site: 00973	file_magic_strength
20	402	cdf_file_property_info	call site: 00402	cdf_file_catalog_info
16	817	file_fmtdatetime	call site: 00817	file_fmtdatetime
12	259	cdf_read_dir	call site: 00259	cdf_swap_dir
12	915	check_regex	call site: 00915	file_magwarn
11	838	file_fmttime	call site: 00838	file_fmtnum
8	102	writechild	call site: 00102	swrite
8	377	cdf_file_property_info	call site: 00377	cdf_app_to_mime
7	850	file_print_guid	call site: 00850	cvt_flip

Runtime coverage analysis

Covered functions

193

Functions that are reachable but not covered

121

Reachable functions

295

Percentage of reachable functions covered

58.98%

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	33
/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/strlcpy.c	1
/src/file/src/softmagic.c	29
/src/file/src/apprentice.c	10
/src/file/src/print.c	9
/src/file/src/der.c	6
/src/file/src/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	454	33.9%
gold	[1:9]	44	3.28%
yellow	[10:29]	44	3.28%
greenyellow	[30:49]	20	1.49%
lawngreen	50+	777	58.0%
All colors	1339	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
50	52	file_or_fd	call site: 00052	magic_file
46	839	mcopy	call site: 00839	file_mdump
33	517	file_tryelf	call site: 00517	file_pipe2file
26	1048	magiccheck	call site: 01048	file_magic_strength
19	479	cdf_file_property_info	call site: 00479	cdf_file_catalog_info
16	892	file_fmtdatetime	call site: 00892	file_fmtdatetime
12	184	uncompressbuf	call site: 00184	writechild
12	336	cdf_read_dir	call site: 00336	cdf_swap_dir
12	990	check_regex	call site: 00990	file_magwarn
11	913	file_fmttime	call site: 00913	file_fmtnum
8	454	cdf_file_property_info	call site: 00454	cdf_app_to_mime
8	1323	file_getbuffer	call site: 01323	handle_mime

Runtime coverage analysis

Covered functions

224

Functions that are reachable but not covered

117

Reachable functions

327

Percentage of reachable functions covered

64.22%

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	33
/src/file/src/fsmagic.c	3
/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/strlcpy.c	1
/src/file/src/softmagic.c	29
/src/file/src/apprentice.c	10
/src/file/src/print.c	9
/src/file/src/der.c	6
/src/file/src/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

293 / 324

Cyclomatic complexity statically reachable by fuzzers

3095 / 3256

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', 'magiccheck', 'cdf_file_property_info', 'file_fmtdatetime', 'cdf_read_dir', 'check_regex', 'file_fmttime', 'writechild']

/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', 'file_tryelf', 'magiccheck', 'cdf_file_property_info', 'file_fmtdatetime', 'uncompressbuf', 'cdf_read_dir', 'check_regex', 'file_fmttime']

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	101	44	43.56%	['magic_fuzzer_loaddb']
check_buffer	57	29	50.87%	['magic_fuzzer', 'magic_fuzzer_loaddb', '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	38	12	31.57%	['magic_fuzzer', 'magic_fuzzer_fd']
cvt_flip	56	26	46.42%	['magic_fuzzer', 'magic_fuzzer_fd']
handle_annotation	36	6	16.66%	['magic_fuzzer', 'magic_fuzzer_fd']
file_fsmagic	183	11	6.010%	['magic_fuzzer_fd']
file_or_fd	82	42	51.21%	['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/fuzzer_temp_file.h	['magic_fuzzer_loaddb', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer_fd']
/src/file/src/is_tar.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/magic_fuzzer_fd.cc	['magic_fuzzer_fd']	['magic_fuzzer_fd']
/src/file/src/buffer.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/fmtcheck.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/strlcpy.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['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/der.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/softmagic.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/is_json.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/encoding.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/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/ascmagic.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/file/src/apprentice.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/readelf.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_fd']
/src/file/src/is_simh.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/compress.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/cdf_time.c	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer_loaddb', 'magic_fuzzer', 'magic_fuzzer_fd']
/src/magic_fuzzer.cc	['magic_fuzzer']	['magic_fuzzer']
/src/file/src/is_csv.c	['magic_fuzzer', 'magic_fuzzer_fd']	['magic_fuzzer', 'magic_fuzzer_fd']
/src/file/src/cdf.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']

Directories in report

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