High level conclusions

Fuzzers reach 94.87% code coverage.

Fuzzers reach 73.82% of cyclomatic complexity.

Fuzzers reach 75.38% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

147 / 195

Cyclomatic complexity statically reachable by fuzzers

2143 / 2903

Runtime code coverage of functions

185 / 195

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: 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	140	17.8%
gold	[1:9]	50	6.36%
yellow	[10:29]	79	10.0%
greenyellow	[30:49]	16	2.03%
lawngreen	50+	501	63.7%
All colors	786	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
22	42	3 : View List ['abort', 'fputs', 'ZydisCalcAbsoluteAddress']	22	42	ZydisValidateInstructionIdentity	call site: 00740	/src/zydis/build/../tools/ZydisFuzzShared.c:261
4	4	2 : View List ['abort', 'fputs']	4	4	ZydisReEncodeInstruction	call site: 00740	/src/zydis/build/../tools/ZydisFuzzShared.c:511
2	2	1 : View List ['fputs']	2	2	ZydisFuzzerInit	call site: 00000	/src/zydis/build/../tools/ZydisFuzzShared.c:528
0	0	None	18	38	ZydisValidateInstructionIdentity	call site: 00752	/src/zydis/build/../tools/ZydisFuzzShared.c:332
0	0	None	18	38	ZydisValidateInstructionIdentity	call site: 00756	/src/zydis/build/../tools/ZydisFuzzShared.c:353
0	0	None	4	4	ZydisValidateInstructionIdentity	call site: 00740	/src/zydis/build/../tools/ZydisFuzzShared.c:273
0	0	None	4	4	ZydisValidateInstructionIdentity	call site: 00746	/src/zydis/build/../tools/ZydisFuzzShared.c:313
0	0	None	4	4	ZydisReEncodeInstruction	call site: 00464	/src/zydis/build/../tools/ZydisFuzzShared.c:482
0	0	None	4	4	ZydisReEncodeInstruction	call site: 00468	/src/zydis/build/../tools/ZydisFuzzShared.c:491
0	0	None	4	4	ZydisReEncodeInstruction	call site: 00736	/src/zydis/build/../tools/ZydisFuzzShared.c:501
0	0	None	4	4	ZydisReEncodeInstructionAbsolute	call site: 00764	/src/zydis/build/../tools/ZydisFuzzShared.c:443
0	0	None	4	4	ZydisReEncodeInstructionAbsolute	call site: 00767	/src/zydis/build/../tools/ZydisFuzzShared.c:459

Runtime coverage analysis

Covered functions

132

Functions that are reachable but not covered

6

Reachable functions

134

Percentage of reachable functions covered

95.52%

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	7
build/../tools/ZydisFuzzReEncoding.c	1
src/Decoder.c	51
src/DecoderData.c	2
src/SharedData.c	4
src/Register.c	5
src/Encoder.c	56
src/EncoderData.c	1
src/Utils.c	1
src/Generated/GetRelInfo.inc	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	166	20.3%
gold	[1:9]	39	4.79%
yellow	[10:29]	93	11.4%
greenyellow	[30:49]	38	4.66%
lawngreen	50+	478	58.7%
All colors	814	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: 00770	/src/zydis/build/../tools/ZydisFuzzShared.c:511
2	2	1 : View List ['fputs']	2	2	ZydisFuzzerInit	call site: 00000	/src/zydis/build/../tools/ZydisFuzzShared.c:528
0	0	None	18	38	ZydisValidateInstructionIdentity	call site: 00780	/src/zydis/build/../tools/ZydisFuzzShared.c:332
0	0	None	18	38	ZydisValidateInstructionIdentity	call site: 00784	/src/zydis/build/../tools/ZydisFuzzShared.c:353
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00668	/src/zydis/build/../tools/ZydisFuzzEncoder.c:99
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00674	/src/zydis/build/../tools/ZydisFuzzEncoder.c:127
0	0	None	12	22	ZydisCompareRequestToInstruction	call site: 00679	/src/zydis/build/../tools/ZydisFuzzEncoder.c:171
0	0	None	4	4	ZydisCompareRequestToInstruction	call site: 00660	/src/zydis/build/../tools/ZydisFuzzEncoder.c:69
0	0	None	4	4	ZydisCompareRequestToInstruction	call site: 00663	/src/zydis/build/../tools/ZydisFuzzEncoder.c:74
0	0	None	4	4	ZydisCompareRequestToInstruction	call site: 00666	/src/zydis/build/../tools/ZydisFuzzEncoder.c:79
0	0	None	4	4	ZydisValidateInstructionIdentity	call site: 00770	/src/zydis/build/../tools/ZydisFuzzShared.c:273
0	0	None	4	4	ZydisValidateInstructionIdentity	call site: 00774	/src/zydis/build/../tools/ZydisFuzzShared.c:313

Runtime coverage analysis

Covered functions

134

Functions that are reachable but not covered

6

Reachable functions

136

Percentage of reachable functions covered

95.59%

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	7
build/../tools/ZydisFuzzEncoder.c	2
src/Encoder.c	56
src/EncoderData.c	1
src/SharedData.c	4
src/Register.c	5
src/Decoder.c	52
src/DecoderData.c	2
src/Utils.c	1
src/Generated/GetRelInfo.inc	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	68	13.7%
gold	[1:9]	64	12.9%
yellow	[10:29]	38	7.69%
greenyellow	[30:49]	11	2.22%
lawngreen	50+	313	63.3%
All colors	494	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:528
0	7	1 : View List ['ZydisFormatterBufferAppendPredefined']	0	82	ZydisFormatterATTPrintMnemonic	call site: 00000	/src/zydis/src/FormatterATT.c:285
0	0	None	12	40	ZydisFormatterATTFormatInstruction	call site: 00000	/src/zydis/src/FormatterATT.c:85
0	0	None	12	40	ZydisFormatterATTFormatInstruction	call site: 00000	/src/zydis/src/FormatterATT.c:116
0	0	None	12	40	ZydisFormatterATTFormatInstruction	call site: 00000	/src/zydis/src/FormatterATT.c:126
0	0	None	12	12	ZydisFormatterIntelFormatInstruction	call site: 00000	/src/zydis/src/FormatterIntel.c:85
0	0	None	12	12	ZydisFormatterIntelFormatInstruction	call site: 00000	/src/zydis/src/FormatterIntel.c:116
0	0	None	12	12	ZydisFormatterIntelFormatInstruction	call site: 00000	/src/zydis/src/FormatterIntel.c:126
0	0	None	0	817	ZydisDecoderDecodeInstruction	call site: 00008	/src/zydis/src/Decoder.c:5031
0	0	None	0	45	ZydisFormatterBasePrintPrefixes	call site: 00000	/src/zydis/src/FormatterBase.c:505
0	0	None	0	45	ZydisFormatterBasePrintPrefixes	call site: 00000	/src/zydis/src/FormatterBase.c:520
0	0	None	0	0	ZydisDecodeInstruction	call site: 00157	/src/zydis/src/Decoder.c:4816

Runtime coverage analysis

Covered functions

126

Functions that are reachable but not covered

5

Reachable functions

90

Percentage of reachable functions covered

94.44%

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/../tools/ZydisFuzzShared.c	4
build/../tools/ZydisFuzzDecoder.c	1
src/Decoder.c	52
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	['N/A', 'N/A', 'N/A']	3	0	1032	226	92	8	0	209	207
ZydisFormatterBasePrintDecorator	/src/zydis/src/FormatterBase.c	4	['N/A', 'N/A', 'N/A', 'int']	2	0	1356	289	110	4	0	195	110
ZydisFormatterIntelFormatOperandMEM	/src/zydis/src/FormatterIntel.c	3	['N/A', 'N/A', 'N/A']	3	0	500	106	44	7	0	80	57
ZydisFormatterIntelFormatInstructionMASM	/src/zydis/src/FormatterIntel.c	3	['N/A', 'N/A', 'N/A']	3	0	41	9	2	5	0	65	53
ZydisFormatterATTFormatInstruction	/src/zydis/src/FormatterATT.c	3	['N/A', 'N/A', 'N/A']	2	0	599	123	47	4	0	63	47
ZydisFormatterIntelPrintTypecast	/src/zydis/src/FormatterIntel.c	3	['N/A', 'N/A', 'N/A']	2	0	326	75	28	4	0	55	43
ZydisFormatterATTFormatOperandMEM	/src/zydis/src/FormatterATT.c	3	['N/A', 'N/A', 'N/A']	3	0	476	102	42	7	0	78	42
ZydisFormatterATTPrintIMM	/src/zydis/src/FormatterATT.c	3	['N/A', 'N/A', 'N/A']	4	0	69	17	5	13	0	93	36

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

Functions statically reachable by fuzzers

171 / 195

Cyclomatic complexity statically reachable by fuzzers

2738 / 2903

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.

build/../tools/ZydisFuzzShared.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=['ZydisValidateInstructionIdentity', 'ZydisReEncodeInstruction', 'ZydisSetAVXInformation', 'ZydisNodeHandlerRexB', 'ZydisSetOperandSizeAndElementInfo', 'ZydisNodeHandlerOpcode', 'ZydisDecodeOptionalInstructionParts', 'ZydisSetAttributes', 'ZydisDecodeOperands']

build/../tools/ZydisFuzzShared.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=['ZydisCompareRequestToInstruction', 'ZydisValidateInstructionIdentity', 'ZydisSetAVXInformation', 'ZydisReEncodeInstruction', 'ZydisNodeHandlerRexB', 'ZydisSetOperandSizeAndElementInfo', 'ZydisIsBroadcastModeCompatible', 'ZydisIsMemoryOperandCompatible', 'ZydisGetEffectiveImmSize', 'ZydisIsImmediateOperandCompabile']

build/../tools/ZydisFuzzShared.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=['ZydisSetAVXInformation', 'ZydisNodeHandlerRexB', 'ZydisSetOperandSizeAndElementInfo', 'ZydisNodeHandlerOpcode', 'ZydisDecodeOptionalInstructionParts', 'ZydisSetAttributes', 'ZydisDecodeOperands', 'ZydisDecodeOperandImplicitMemory', 'ZydisValidateEnumRanges', 'ZydisNodeHandlerXOP']

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
ZydisCompareRequestToInstruction	153	69	45.09%	['ZydisFuzzEncoder']

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

Directories in report

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