High level conclusions

Fuzzers reach 66.66% code coverage.

Fuzzers reach 72.46% of cyclomatic complexity.

Fuzzers reach 73.95% of all functions.

Fuzzer ZydisFuzzDecoder is blocked:

The runtime code coverage of ZydisFuzzDecoder covers 7.865% 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

142 / 192

Cyclomatic complexity statically reachable by fuzzers

2071 / 2858

Runtime code coverage of functions

128 / 192

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: ZydisFuzzReEncoding

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	127	16.5%
gold	[1:9]	60	7.80%
yellow	[10:29]	70	9.10%
greenyellow	[30:49]	36	4.68%
lawngreen	50+	476	61.8%
All colors	769	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
4	4	2 : View List ['abort', 'fputs']	4	4	ZydisReEncodeInstruction	call site: 00750	/src/zydis/build/../tools/ZydisFuzzShared.c:402
2	2	1 : View List ['fputs']	4	4	ZydisValidateInstructionIdentity	call site: 00750	/src/zydis/build/../tools/ZydisFuzzShared.c:240
2	2	1 : View List ['fputs']	2	2	ZydisFuzzerInit	call site: 00000	/src/zydis/build/../tools/ZydisFuzzShared.c:417
0	28	1 : View List ['ZydisGetOperandSizeFromElementSize']	0	28	ZydisGetScaledImmSize	call site: 00613	/src/zydis/src/Encoder.c:408
0	0	None	12	32	ZydisValidateInstructionIdentity	call site: 00758	/src/zydis/build/../tools/ZydisFuzzShared.c:310
0	0	None	12	32	ZydisValidateInstructionIdentity	call site: 00762	/src/zydis/build/../tools/ZydisFuzzShared.c:326
0	0	None	4	4	ZydisReEncodeInstruction	call site: 00480	/src/zydis/build/../tools/ZydisFuzzShared.c:373
0	0	None	4	4	ZydisReEncodeInstruction	call site: 00485	/src/zydis/build/../tools/ZydisFuzzShared.c:382
0	0	None	4	4	ZydisReEncodeInstruction	call site: 00746	/src/zydis/build/../tools/ZydisFuzzShared.c:392
0	0	None	2	2	ZydisValidateInstructionIdentity	call site: 00752	/src/zydis/build/../tools/ZydisFuzzShared.c:261
0	0	None	2	2	ZydisValidateInstructionIdentity	call site: 00754	/src/zydis/build/../tools/ZydisFuzzShared.c:270
0	0	None	2	2	ZydisValidateInstructionIdentity	call site: 00760	/src/zydis/build/../tools/ZydisFuzzShared.c:318

Runtime coverage analysis

Covered functions

127

Functions that are reachable but not covered

5

Reachable functions

128

Percentage of reachable functions covered

96.09%

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/../tools/ZydisFuzzShared.c	5
build/../tools/ZydisFuzzReEncoding.c	1
src/Decoder.c	50
src/DecoderData.c	2
src/SharedData.c	4
src/Register.c	5
src/Encoder.c	54
src/Utils.c	1
src/EncoderData.c	1

Fuzzer: ZydisFuzzEncoder

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	149	18.8%
gold	[1:9]	37	4.67%
yellow	[10:29]	73	9.22%
greenyellow	[30:49]	52	6.57%
lawngreen	50+	480	60.6%
All colors	791	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
4	4	2 : View List ['abort', 'fputs']	4	4	ZydisReEncodeInstruction	call site: 00772	/src/zydis/build/../tools/ZydisFuzzShared.c:402
2	2	1 : View List ['fputs']	4	4	ZydisValidateInstructionIdentity	call site: 00772	/src/zydis/build/../tools/ZydisFuzzShared.c:240
2	2	1 : View List ['fputs']	2	2	ZydisFuzzerInit	call site: 00000	/src/zydis/build/../tools/ZydisFuzzShared.c:417
0	0	None	12	32	ZydisValidateInstructionIdentity	call site: 00778	/src/zydis/build/../tools/ZydisFuzzShared.c:277
0	0	None	12	32	ZydisValidateInstructionIdentity	call site: 00784	/src/zydis/build/../tools/ZydisFuzzShared.c:326
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00717	/src/zydis/build/../tools/ZydisFuzzEncoder.c:99
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00722	/src/zydis/build/../tools/ZydisFuzzEncoder.c:155
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00725	/src/zydis/build/../tools/ZydisFuzzEncoder.c:177
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00725	/src/zydis/build/../tools/ZydisFuzzEncoder.c:188
0	0	None	4	4	ZydisCompareRequestToInstruction	call site: 00711	/src/zydis/build/../tools/ZydisFuzzEncoder.c:69
0	0	None	4	4	ZydisCompareRequestToInstruction	call site: 00714	/src/zydis/build/../tools/ZydisFuzzEncoder.c:74
0	0	None	4	4	ZydisCompareRequestToInstruction	call site: 00716	/src/zydis/build/../tools/ZydisFuzzEncoder.c:79

Runtime coverage analysis

Covered functions

129

Functions that are reachable but not covered

5

Reachable functions

130

Percentage of reachable functions covered

96.15%

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/../tools/ZydisFuzzShared.c	5
build/../tools/ZydisFuzzEncoder.c	2
src/Encoder.c	54
src/EncoderData.c	1
src/SharedData.c	4
src/Register.c	5
src/Decoder.c	51
src/DecoderData.c	2
src/Utils.c	1

Fuzzer: ZydisFuzzDecoder

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	503	98.4%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	8	1.56%
All colors	511	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
2	2	1 : View List ['fputs']	2	2	ZydisFuzzerInit	call site: 00000	/src/zydis/build/../tools/ZydisFuzzShared.c:417
0	0	None	0	0	ZydisLibFuzzerRead	call site: 00510	/src/zydis/build/../tools/ZydisFuzzShared.c:66

Runtime coverage analysis

Covered functions

10

Functions that are reachable but not covered

82

Reachable functions

89

Percentage of reachable functions covered

7.87%

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/../tools/ZydisFuzzShared.c	3
build/../tools/ZydisFuzzDecoder.c	1
src/Decoder.c	51
src/Formatter.c	8
src/DecoderData.c	2
src/SharedData.c	4
src/Register.c	8
src/FormatterBuffer.c	2
src/Utils.c	1
src/Mnemonic.c	2
src/Segment.c	1
src/Zydis.c	1

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
ZydisFormatterBasePrintPrefixes	/src/zydis/src/FormatterBase.c	3	['struct.ZydisFormatter_ *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	2	0	1064	226	92	8	0	170	168
ZydisFormatterBasePrintDecorator	/src/zydis/src/FormatterBase.c	4	['struct.ZydisFormatter_ *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *', 'int ']	1	0	1395	289	110	4	0	155	110
ZydisEncoderEncodeInstructionAbsolute	/src/zydis/src/Encoder.c	4	['struct.ZydisEncoderRequest_ *', 'char *', 'size_t *', 'size_t ']	5	0	569	105	39	60	0	929	72
ZydisFormatterIntelFormatOperandMEM	/src/zydis/src/FormatterIntel.c	3	['struct.ZydisFormatter_.273 *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	2	0	498	104	43	7	0	80	56
ZydisFormatterIntelFormatInstructionMASM	/src/zydis/src/FormatterIntel.c	3	['struct.ZydisFormatter_.273 *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	2	0	41	9	2	5	0	65	53
ZydisFormatterATTFormatInstruction	/src/zydis/src/FormatterATT.c	3	['struct.ZydisFormatter_.202 *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	1	0	607	123	47	4	0	63	47
ZydisFormatterATTFormatOperandMEM	/src/zydis/src/FormatterATT.c	3	['struct.ZydisFormatter_.202 *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	2	0	481	102	42	7	0	79	42
ZydisFormatterIntelPrintTypecast	/src/zydis/src/FormatterIntel.c	3	['struct.ZydisFormatter_.273 *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	1	0	335	75	28	4	0	52	40
ZydisFormatterATTPrintIMM	/src/zydis/src/FormatterATT.c	3	['struct.ZydisFormatter_.202 *', 'struct.ZydisFormatterBuffer_ *', 'struct.ZydisFormatterContext_ *']	3	0	70	17	5	13	0	94	36

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

Functions statically reachable by fuzzers

168 / 192

Cyclomatic complexity statically reachable by fuzzers

2695 / 2858

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 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
ZydisCalcAbsoluteAddress	74	26	35.13%	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']

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/zydis/build/../tools/ZydisFuzzDecoder.c	['ZydisFuzzDecoder']	[]
/src/zydis/build/../tools/ZydisFuzzShared.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']	[]
/src/zydis/src/Decoder.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']
/src/zydis/src/Zydis.c	['ZydisFuzzDecoder']	['ZydisFuzzDecoder']
/src/zydis/src/Register.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']
/src/zydis/include/Zydis/Internal/String.h	[]	[]
/src/zydis/src/FormatterBase.c	[]	[]
/src/zydis/build/../tools/ZydisFuzzReEncoding.c	['ZydisFuzzReEncoding']	[]
/src/zydis/src/Segment.c	['ZydisFuzzDecoder']	[]
/src/zydis/include/Zydis/Internal/FormatterBase.h	[]	[]
/src/zydis/src/FormatterATT.c	[]	[]
/src/zydis/src/Formatter.c	['ZydisFuzzDecoder']	['ZydisFuzzDecoder']
/src/zydis/src/Utils.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']
/src/zydis/build/../tools/ZydisFuzzEncoder.c	['ZydisFuzzEncoder']	[]
/src/zydis/src/DecoderData.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']
/src/zydis/src/Mnemonic.c	['ZydisFuzzDecoder']	[]
/src/zydis/src/SharedData.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder', 'ZydisFuzzDecoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']
/src/zydis/src/EncoderData.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']
/src/zydis/src/FormatterBuffer.c	['ZydisFuzzDecoder']	[]
/src/zydis/dependencies/zycore/include/Zycore/Format.h	[]	[]
/src/zydis/src/FormatterIntel.c	[]	[]
/src/zydis/src/Generated/GetRelInfo.inc	[]	[]
/src/zydis/src/Encoder.c	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']	['ZydisFuzzReEncoding', 'ZydisFuzzEncoder']
/src/zydis/src/String.c	[]	[]

Directories in report

Directory
/src/zydis/build/../tools/
/src/zydis/src/
/src/zydis/include/Zydis/Internal/
/src/zydis/src/Generated/
/src/zydis/dependencies/zycore/include/Zycore/