Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues
Project coverage
Per-fuzzer coverage

Table of contents

Project overview: libtiff
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: tiff_read_rgba_fuzzer
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Fuzzer: write_fuzzer
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/libtiff/contrib/oss-fuzz/tiff_read_rgba_fuzzer.cc
Dictionary
Fuzzer function priority
/src/libtiff/contrib/oss-fuzz/write_fuzzer.cc
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2026-07-16

Project overview: libtiff

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
24.0%
380 / 1554
Cyclomatic complexity statically reachable by fuzzers
23.0%
3305 / 14334
Runtime code coverage of functions
6.0%
96 / 1554

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
tiff_read_rgba_fuzzer /src/libtiff/contrib/oss-fuzz/tiff_read_rgba_fuzzer.cc 399 1339 15 31 9342 3330 tiff_read_rgba_fuzzer.cc
write_fuzzer /src/libtiff/contrib/oss-fuzz/write_fuzzer.cc 326 1307 15 19 8199 2895 write_fuzzer.cc

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 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 details

Fuzzer: tiff_read_rgba_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

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 2094 100.%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 0 0.0%
All colors 2094 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
2093 0 EP call site: 00000 TIFFClientOpen

Runtime coverage analysis

Covered functions
0
Functions that are reachable but not covered
399
Reachable functions
399
Percentage of reachable functions covered
0.0%
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/libtiff/contrib/oss-fuzz/tiff_read_rgba_fuzzer.cc 2
/src/libtiff/libtiff/tif_error.c 4
/src/libtiff/libtiff/tif_warning.c 2
/src/libtiff/libtiff/tif_stream.cxx 16
/src/libtiff/libtiff/tif_open.c 11
/src/libtiff/libtiff/tif_unix.c 7
/src/libtiff/libtiff/tif_dir.c 13
/src/libtiff/libtiff/tif_compress.c 3
/src/libtiff/libtiff/tif_swab.c 9
/src/libtiff/libtiff/tif_dirinfo.c 12
/src/libtiff/libtiff/tif_aux.c 14
/src/libtiff/libtiff/tif_dirread.c 114
/src/libtiff/libtiff/tif_hash_set.c 13
/src/libtiff/libtiff/tif_codec.c 1
/src/libtiff/libtiff/tif_strip.c 7
/src/libtiff/libtiff/tif_tile.c 5
/src/libtiff/libtiff/tif_write.c 3
/src/libtiff/libtiff/tif_close.c 3
/src/libtiff/libtiff/tif_flush.c 3
/src/libtiff/libtiff/tif_dirwrite.c 69
/src/libtiff/libtiff/tif_getimage.c 20
/src/libtiff/libtiff/tif_color.c 3
/src/libtiff/libtiff/tif_read.c 11
/src/libtiff/libtiff/tif_jpeg.c 6
/src/libjpeg-turbo/src/jerror.c 1
/src/libjpeg-turbo/src/jdapimin.c 5
/src/libjpeg-turbo/src/jmemmgr.c 1
/src/libjpeg-turbo/src/jmemnobs.c 3
/src/libjpeg-turbo/src/jdmarker.c 2
/src/libjpeg-turbo/src/jdinput.c 1
/src/libjpeg-turbo/src/jcomapi.c 2

Fuzzer: write_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

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 1684 89.2%
gold [1:9] 2 0.10%
yellow [10:29] 0 0.0%
greenyellow [30:49] 2 0.10%
lawngreen 50+ 198 10.4%
All colors 1886 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
721 199 TIFFFreeDirectory call site: 00199 TIFFFetchNormalTag
230 1420 TIFFWriteDirectorySec call site: 01420 TIFFWriteDirectoryTagLongLong8Array
90 1653 TIFFWriteDirectorySec call site: 01653 TIFFRewriteDirectorySec
84 947 _TIFFFillStriles call site: 00947 TIFFFetchNormalTag
60 1112 _TIFFStrileSize64 call site: 01112 ChopUpSingleUncompressedStrip
55 1039 TIFFSetupStrips call site: 01039 EstimateStripByteCounts
50 1217 TIFFAppendToStrip call site: 01217 TIFFForceStrileArrayWriting
48 132 _TIFFCheckDirNumberAndOffset call site: 00132 TIFFFetchDirectory
45 1268 WriteAsLong4 call site: 01268 _TIFFRewriteField
25 921 TIFFFieldWithTag call site: 00921 TIFFFetchNormalTag
19 1174 TIFFVStripSize64 call site: 01174 TryChopUpUncompressedBigTiff
19 1341 TIFFWriteDirectorySec call site: 01341 TIFFWriteDirectoryTagRational

Runtime coverage analysis

Covered functions
97
Functions that are reachable but not covered
237
Reachable functions
326
Percentage of reachable functions covered
27.3%
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/libtiff/contrib/oss-fuzz/write_fuzzer.cc 1
/src/libtiff/libtiff/tif_unix.c 17
/src/libtiff/libtiff/tif_open.c 9
/src/libtiff/libtiff/tif_error.c 3
/src/libtiff/libtiff/tif_dir.c 13
/src/libtiff/libtiff/tif_compress.c 2
/src/libtiff/libtiff/tif_warning.c 1
/src/libtiff/libtiff/tif_swab.c 9
/src/libtiff/libtiff/tif_dirinfo.c 12
/src/libtiff/libtiff/tif_aux.c 13
/src/libtiff/libtiff/tif_dirread.c 114
/src/libtiff/libtiff/tif_hash_set.c 13
/src/libtiff/libtiff/tif_codec.c 1
/src/libtiff/libtiff/tif_strip.c 7
/src/libtiff/libtiff/tif_tile.c 5
/src/libtiff/libtiff/tif_write.c 8
/src/libtiff/libtiff/tif_close.c 3
/src/libtiff/libtiff/tif_flush.c 3
/src/libtiff/libtiff/tif_dirwrite.c 69

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
OJPEGPreDecode /src/libtiff/libtiff/tif_ojpeg.c 2 ['N/A', 'short'] 16 0 371 52 20 164 0 1453 1050
JPEGPreEncode /src/libtiff/libtiff/tif_jpeg.c 2 ['N/A', 'short'] 9 0 475 67 24 96 0 862 672
encode_mcu_huff /src/libjpeg-turbo/src/jchuff.c 2 ['N/A', 'N/A'] 3 0 228 33 14 5 0 592 592
PixarLogEncode /src/libtiff/libtiff/tif_pixarlog.c 4 ['N/A', 'N/A', 'size_t', 'short'] 6 0 337 41 8 51 0 570 492
PixarLogDecode /src/libtiff/libtiff/tif_pixarlog.c 4 ['N/A', 'N/A', 'size_t', 'short'] 4 0 627 72 18 23 0 427 371
read_markers /src/libjpeg-turbo/src/jdmarker.c 1 ['N/A'] 2 0 830 187 34 12 0 245 241
Fax3Decode2D /src/libtiff/libtiff/tif_fax3.c 4 ['N/A', 'N/A', 'size_t', 'short'] 2 0 5618 860 211 8 0 247 231
_TIFFVSetField /src/libtiff/libtiff/tif_dir.c 3 ['N/A', 'int', 'N/A'] 6 0 4362 611 182 37 0 397 219
gtTileSeparate /src/libtiff/libtiff/tif_getimage.c 4 ['N/A', 'N/A', 'int', 'int'] 16 0 865 120 41 88 0 747 208
decode_mcu /src/libjpeg-turbo/src/jdhuff.c 2 ['N/A', 'N/A'] 3 0 135 30 13 5 0 183 183

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

Functions statically reachable by fuzzers
41.0%
641 / 1554
Cyclomatic complexity statically reachable by fuzzers
53.0%
7558 / 14334

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

Fuzz engine guidance

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/libtiff/contrib/oss-fuzz/tiff_read_rgba_fuzzer.cc

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


/src/libtiff/contrib/oss-fuzz/write_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=['TIFFFreeDirectory', 'TIFFWriteDirectorySec', '_TIFFFillStriles', '_TIFFStrileSize64', 'TIFFSetupStrips', 'TIFFAppendToStrip', '_TIFFCheckDirNumberAndOffset', 'WriteAsLong4', 'TIFFFieldWithTag']

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
LLVMFuzzerTestOneInput 93 39 41.93%
TIFFCleanup 52 25 48.07% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
_TIFFVSetField 804 70 8.706% ['write_fuzzer']
_TIFFCheckDirNumberAndOffset 126 34 26.98% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
_TIFFFillStrilesInternal 35 5 14.28% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFRewriteDirectorySec 138 4 2.898% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFWriteDirectorySec 875 238 27.20% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFLinkDirectory 199 22 11.05% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFHashSetInsert 37 15 40.54% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
_TIFFreallocExt 37 5 13.51% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFClientOpenExt 337 89 26.40% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
_TIFFStrileSize64 58 15 25.86% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFScanlineSize64 68 26 38.23% ['write_fuzzer', 'tiff_read_rgba_fuzzer']
TIFFWriteEncodedStrip 72 29 40.27% ['write_fuzzer']
TIFFWriteCheck 53 20 37.73% ['write_fuzzer']
TIFFAppendToStrip 133 35 26.31% ['write_fuzzer', 'tiff_read_rgba_fuzzer']

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
[] []
/src/libtiff/libtiff/tif_lzma.c [] []
/src/libjpeg-turbo/src/jcinit.c [] []
/src/libjpeg-turbo/src/wrapper/../jcmainct.c [] []
/src/libjpeg-turbo/src/jdarith.c [] []
/src/libjpeg-turbo/src/wrapper/../jddiffct.c [] []
/src/libtiff/libtiff/tif_dirread.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/jcmarker.c [] []
/src/libtiff/libtiff/tif_dir.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libtiff/contrib/oss-fuzz/tiff_read_rgba_fuzzer.cc ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/wrapper/../jccoefct.c [] []
/src/libtiff/libtiff/tif_warning.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] []
/src/libtiff/libtiff/tif_codec.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] []
/src/libtiff/libtiff/tif_color.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/jdlhuff.c [] []
/src/libjpeg-turbo/src/jcapimin.c [] []
/src/libtiff/contrib/oss-fuzz/write_fuzzer.cc ['write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/wrapper/../jdmainct.c [] []
/src/libtiff/libtiff/tif_stream.cxx ['tiff_read_rgba_fuzzer'] []
/usr/local/bin/../include/c++/v1/stdexcept [] []
/src/libjpeg-turbo/src/wrapper/../jdmerge.c [] []
/src/zlib/crc32.c [] []
/src/libjpeg-turbo/src/wrapper/../jdmainct.h [] []
/src/libjpeg-turbo/src/wrapper/../jddctmgr.c [] []
/src/libtiff/libtiff/tif_next.c [] []
/src/libjpeg-turbo/src/wrapper/../jutils.c [] []
/src/libtiff/libtiff/tif_lzw.c [] []
/src/libjpeg-turbo/src/jmemnobs.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/jcarith.c [] []
/src/libjpeg-turbo/src/jdmaster.c [] []
/src/libjpeg-turbo/src/wrapper/../jdmrgext.c [] []
/src/libjpeg-turbo/src/wrapper/../jccolor.c [] []
/src/libtiff/libtiff/tif_packbits.c [] []
/src/libjpeg-turbo/src/wrapper/../jdsample.c [] []
/src/libjpeg-turbo/src/jdapimin.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/jdhuff.c [] []
/src/zlib/zutil.c [] []
/src/zlib/inffast.c [] []
/src/libjpeg-turbo/src/wrapper/../jdcoefct.c [] []
/src/libtiff/libtiff/tif_unix.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/wrapper/../jcsample.c [] []
/src/libjpeg-turbo/src/wrapper/../jidctred.c [] []
/src/libjpeg-turbo/src/wrapper/../jccolext.c [] []
/src/libtiff/libtiff/tif_tile.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] []
/src/libjpeg-turbo/src/jerror.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/wrapper/../jclossls.c [] []
/src/libjpeg-turbo/simd/jsimd.c [] []
/src/zlib/trees.c [] []
/src/libtiff/libtiff/tif_thunder.c [] []
/src/libjpeg-turbo/src/wrapper/../jquant1.c [] []
/src/libtiff/libtiff/tif_close.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libtiff/libtiff/tif_fax3.c [] []
/src/libtiff/libtiff/tif_error.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libtiff/libtiff/tif_dumpmode.c [] []
/src/libjpeg-turbo/src/jdinput.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/wrapper/../jidctfst.c [] []
/src/libjpeg-turbo/src/wrapper/../jdapistd.c [] []
/src/libtiff/libtiff/tif_compress.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/jcparam.c [] []
/src/libjpeg-turbo/src/jdphuff.c [] []
/src/libjpeg-turbo/src/wrapper/../jdlossls.c [] []
/src/libjpeg-turbo/src/jcphuff.c [] []
/src/libjpeg-turbo/src/jclhuff.c [] []
/src/libjpeg-turbo/src/jstdhuff.c [] []
/src/libtiff/libtiff/tif_aux.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/wrapper/../jcapistd.c [] []
/src/libtiff/libtiff/tif_luv.c [] []
/src/libtiff/libtiff/tif_getimage.c ['tiff_read_rgba_fuzzer'] []
/src/libtiff/libtiff/tif_dirwrite.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/jcmaster.c [] []
/src/libtiff/libtiff/tif_dirinfo.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/jchuff.c [] []
/src/libtiff/libtiff/tif_predict.c [] []
/src/libjpeg-turbo/src/wrapper/../jdcolor.c [] []
/src/libjpeg-turbo/src/wrapper/../jcdiffct.c [] []
/src/libtiff/libtiff/tif_write.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libtiff/libtiff/tif_strip.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libtiff/libtiff/tif_ojpeg.c [] []
/src/libtiff/libtiff/tif_open.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/libjpeg-turbo/src/wrapper/../jquant2.c [] []
/src/libtiff/libtiff/tif_pixarlog.c [] []
/src/zlib/inftrees.c [] []
/src/libjpeg-turbo/src/wrapper/../jidctint.c [] []
/src/libjpeg-turbo/src/wrapper/../jfdctfst.c [] []
/src/libtiff/libtiff/tif_jpeg.c ['tiff_read_rgba_fuzzer'] []
/src/libtiff/libtiff/tif_swab.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] []
/src/libjpeg-turbo/src/jdmarker.c ['tiff_read_rgba_fuzzer'] []
/src/libtiff/libtiff/tif_flush.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/zlib/deflate.c [] []
/src/libjpeg-turbo/src/wrapper/../jdcolext.c [] []
/src/libjpeg-turbo/src/wrapper/../jidctflt.c [] []
/src/libjpeg-turbo/src/wrapper/../jfdctint.c [] []
/src/libtiff/libtiff/tif_read.c ['tiff_read_rgba_fuzzer'] []
/src/libtiff/libtiff/tif_zip.c [] []
/src/libtiff/libtiff/tif_jbig.c [] []
/src/libjpeg-turbo/src/wrapper/../jdpostct.c [] []
/src/libjpeg-turbo/src/wrapper/../jcprepct.c [] []
/src/zlib/adler32.c [] []
/src/libtiff/libtiff/tif_hash_set.c ['tiff_read_rgba_fuzzer', 'write_fuzzer'] ['write_fuzzer']
/src/zlib/inflate.c [] []
/src/libjpeg-turbo/src/wrapper/../jcdctmgr.c [] []
/src/libjpeg-turbo/src/jcomapi.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/jmemmgr.c ['tiff_read_rgba_fuzzer'] []
/src/libjpeg-turbo/src/jfdctflt.c [] []

Directories in report

Directory
/src/libjpeg-turbo/simd/
/src/zlib/
/src/libtiff/libtiff/
/usr/local/bin/../include/c++/v1/
/src/libtiff/contrib/oss-fuzz/
/src/libjpeg-turbo/src/wrapper/../
/src/libjpeg-turbo/src/

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
tiff_read_rgba_fuzzer fuzzerLogFile-0-lugeMLPM5t.data fuzzerLogFile-0-lugeMLPM5t.data.yaml tiff_read_rgba_fuzzer.covreport
write_fuzzer fuzzerLogFile-0-6IIW8Y3SVC.data fuzzerLogFile-0-6IIW8Y3SVC.data.yaml write_fuzzer.covreport