Report generation date: 2023-03-26

Project overview: snappy-java

High level conclusions

The runtime code coverage of SnappyStreamFuzzer covers 13.88% of its statically reachable code. This means there is some place that blocks the fuzzer to continue exploring more code at run time.

Fuzzers reach 23.48% of cyclomatic complexity.

Fuzzers reach 21.90% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

62/283

Cyclomatic complexity statically reachable by fuzzers

62/264

Runtime code coverage of functions

65 / 283

Fuzzers overview

Fuzzer	Fuzzer filename	Functions Reached	Functions unreached	Fuzzer depth	Files reached	Basic blocks reached	Cyclomatic complexity	Details
SnappyStreamFuzzer	SnappyStreamFuzzer	108	241	10	15	146	46	SnappyStreamFuzzer
BitShuffleFuzzer	BitShuffleFuzzer	48	260	5	5	50	17	BitShuffleFuzzer

Project functions overview

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 details

Fuzzer: SnappyStreamFuzzer

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

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color Runtime hitcount Callsite count Percentage

red 0 34 53.9%

gold [1:9] 0 0.0%

yellow [10:29] 0 0.0%

greenyellow [30:49] 0 0.0%

lawngreen 50+ 29 46.0%

All colors 63 100

Color	Runtime hitcount	Callsite count	Percentage
red	0	34	53.9%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	29	46.0%
All colors	63	100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked	Calltree index	Parent function	Callsite
16	40	[org.xerial.snappy.SnappyOutputStream].close()	call site: 00040
15	11	[org.xerial.snappy.SnappyOutputStream].dumpOutput()	call site: 00011
2	29	[org.xerial.snappy.SnappyOutputStream].compressInput()	call site: 00029
1	38	[org.xerial.snappy.SnappyOutputStream].flush()	call site: 00038

Runtime coverage analysis

Covered functions

55

Functions that are reachable but not covered

93

Reachable functions

108

Percentage of reachable functions covered

13.89%

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
SnappyStreamFuzzer	1
org.xerial.snappy.SnappyOutputStream	10
org.xerial.snappy.SnappyHadoopCompatibleOutputStream	2
org.xerial.snappy.SnappyCodec	1
org.xerial.snappy.Snappy	4
org.xerial.snappy.SnappyNative	3
org.xerial.snappy.SnappyFramedOutputStream	7
org.xerial.snappy.SnappyFramed	2
org.xerial.snappy.PureJavaCrc32C	3
org.xerial.snappy.pool.QuiescentBufferPool	2
org.xerial.snappy.pool.CachingBufferPool	3
org.xerial.snappy.pool.DirectByteBuffers	1
org.xerial.snappy.pool.DirectByteBuffers$2	1
org.xerial.snappy.buffer.CachedBufferAllocator	1
org.xerial.snappy.buffer.DefaultBufferAllocator	1

Fuzzer: BitShuffleFuzzer

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

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color Runtime hitcount Callsite count Percentage

red 0 0 0.0%

gold [1:9] 0 0.0%

yellow [10:29] 0 0.0%

greenyellow [30:49] 0 0.0%

lawngreen 50+ 31 100.%

All colors 31 100

Color	Runtime hitcount	Callsite count	Percentage
red	0	0	0.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	31	100.%
All colors	31	100

Runtime coverage analysis

Covered functions

52

Functions that are reachable but not covered

31

Reachable functions

48

Percentage of reachable functions covered

35.42%

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
BitShuffleFuzzer	4
org.xerial.snappy.BitShuffle	6
org.xerial.snappy.BitShuffleNative	2
org.xerial.snappy.Snappy	7
org.xerial.snappy.SnappyNative	4

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
`[org.xerial.snappy.SnappyLoader].extractLibraryFile(java.lang.String,java.lang.String,java.lang.String)`	org.xerial.snappy.SnappyLoader	3	['java.lang.String', 'java.lang.String', 'java.lang.String']	7	0	95	33	2	164	4	65	47

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

Functions statically reachable by fuzzers

103/283

Cyclomatic complexity statically reachable by fuzzers

109 / 264

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

Runtime coverage analysis

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
[org.xerial.snappy.SnappyOutputStream].write(byte[],int,int)	34	13	38.23%	['SnappyStreamFuzzer']
[org.xerial.snappy.Snappy].compress(java.nio.ByteBuffer,java.nio.ByteBuffer)	47	0	0.0%	['SnappyStreamFuzzer']
[org.xerial.snappy.Snappy].uncompressedLength(java.nio.ByteBuffer)	40	0	0.0%	[]
[org.xerial.snappy.BitShuffle].unshuffleDoubleArray(byte[])	59	11	18.64%	[]
[org.xerial.snappy.SnappyInputStream].read(byte[],int,int)	34	12	35.29%	[]

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
org.xerial.snappy.OSInfo	[]	[]
org.xerial.snappy.SnappyOutputStream	['SnappyStreamFuzzer']	[]
org.xerial.snappy.Snappy	['SnappyStreamFuzzer', 'BitShuffleFuzzer']	[]
org.xerial.snappy.pool.DirectByteBuffers$1	[]	[]
org.xerial.snappy.BitShuffleNative	['BitShuffleFuzzer']	[]
org.xerial.snappy.SnappyFramed$lambda_static_0__1	[]	[]
org.xerial.snappy.pool.CachingBufferPool$IntFunction	[]	[]
org.xerial.snappy.pool.DirectByteBuffers$2	['SnappyStreamFuzzer']	[]
org.xerial.snappy.SnappyFramed	['SnappyStreamFuzzer']	[]
org.xerial.snappy.PureJavaCrc32C	['SnappyStreamFuzzer']	[]
org.xerial.snappy.pool.CachingBufferPool	['SnappyStreamFuzzer']	[]
org.xerial.snappy.buffer.BufferAllocator	[]	[]
SnappyStreamFuzzer	['SnappyStreamFuzzer']	[]
org.xerial.snappy.buffer.BufferAllocatorFactory	[]	[]
org.xerial.snappy.SnappyFramedInputStream$FrameAction	[]	[]
org.xerial.snappy.SnappyError	[]	[]
org.xerial.snappy.pool.CachingBufferPool$2	[]	[]
org.xerial.snappy.BitShuffleType	[]	[]
org.xerial.snappy.SnappyErrorCode	[]	[]
org.xerial.snappy.pool.BufferPool	[]	[]
org.xerial.snappy.SnappyFramedInputStream	[]	[]
org.xerial.snappy.pool.DirectByteBuffers	['SnappyStreamFuzzer']	[]
org.xerial.snappy.pool.DefaultPoolFactory	[]	[]
org.xerial.snappy.buffer.CachedBufferAllocator$1	[]	[]
org.xerial.snappy.SnappyNative	['SnappyStreamFuzzer', 'BitShuffleFuzzer']	[]
org.xerial.snappy.pool.QuiescentBufferPool	['SnappyStreamFuzzer']	[]
org.xerial.snappy.SnappyLoader	[]	[]
org.xerial.snappy.BitShuffle	['BitShuffleFuzzer']	[]
org.xerial.snappy.SnappyApi	[]	[]
org.xerial.snappy.buffer.CachedBufferAllocator	['SnappyStreamFuzzer']	[]
org.xerial.snappy.SnappyHadoopCompatibleOutputStream	['SnappyStreamFuzzer']	[]
org.xerial.snappy.buffer.DefaultBufferAllocator$1	[]	[]
org.xerial.snappy.SnappyInputStream	[]	[]
org.xerial.snappy.buffer.DefaultBufferAllocator	['SnappyStreamFuzzer']	[]
org.xerial.snappy.SnappyBundleActivator	[]	[]
org.xerial.snappy.SnappyException	[]	[]
org.xerial.snappy.SnappyFramed$init__2	[]	[]
BitShuffleFuzzer	['BitShuffleFuzzer']	[]
org.xerial.snappy.SnappyIOException	[]	[]
java.lang.System	[]	[]
org.xerial.snappy.pool.CachingBufferPool$1	[]	[]
java.lang.Runtime	[]	[]
org.xerial.snappy.SnappyFramedOutputStream	['SnappyStreamFuzzer']	[]
org.xerial.snappy.SnappyCodec	['SnappyStreamFuzzer']	[]

Directories in report

Directory

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file

SnappyStreamFuzzer fuzzerLogFile-SnappyStreamFuzzer.data fuzzerLogFile-SnappyStreamFuzzer.data.yaml jacoco.xml

BitShuffleFuzzer fuzzerLogFile-BitShuffleFuzzer.data fuzzerLogFile-BitShuffleFuzzer.data.yaml jacoco.xml

Fuzzer	Calltree file	Program data file	Coverage file
SnappyStreamFuzzer	fuzzerLogFile-SnappyStreamFuzzer.data	fuzzerLogFile-SnappyStreamFuzzer.data.yaml	jacoco.xml
BitShuffleFuzzer	fuzzerLogFile-BitShuffleFuzzer.data	fuzzerLogFile-BitShuffleFuzzer.data.yaml	jacoco.xml

Function call coverage

This section shows a chosen list of functions / methods calls and their relative coverage information. By static analysis of the target project code, all of these function call and their caller information, including the source file or class and line number that initiate the call are captured. Column 1 is the function name of that selected functions or methods. Column 2 of each row indicate if the target function covered by any fuzzer calltree information. Column 3 lists all fuzzers (or no fuzzers at all) that have coered that particular function call dynamically. Column 4 shows list of parent function for the specific function call, while column 5 shows possible blocker functions that make the fuzzers fail to reach the specific functions. Both column 4 and 5 will only show information if none of the fuzzers cover the target function calls.