Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues

Fuzzer details

Fuzzer: decode_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 0 119 32.8%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 243 67.1%
All colors 362 100

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
538 670 2 :

['ov_clear', '_open_seekable2']

538 670 _ov_open2 call site: 00174 /src/vorbis/lib/vorbisfile.c:942
166 166 3 :

['vorbis_book_init_encode', 'drft_init', '_vp_psy_init']

176 176 _vds_shared_init call site: 00258 /src/vorbis/lib/block.c:210
11 11 1 :

['_vp_psy_clear']

14 26 vorbis_dsp_clear call site: 00161 /src/vorbis/lib/block.c:354
8 8 1 :

['_ve_envelope_clear']

22 44 vorbis_dsp_clear call site: 00157 /src/vorbis/lib/block.c:324
4 22 2 :

['realloc', 'ogg_stream_clear']

4 22 _os_lacing_expand call site: 00051 /src/ogg/src/framing.c:206
0 23 2 :

['ogg_sync_buffer', 'ogg_sync_wrote']

10 528 _ov_open1 call site: 00004 /src/vorbis/lib/vorbisfile.c:898
0 0 None 0 1035 _fetch_and_process_packet call site: 00335 /src/vorbis/lib/vorbisfile.c:797
0 0 None 0 1035 _fetch_and_process_packet call site: 00338 /src/vorbis/lib/vorbisfile.c:833
0 0 None 0 312 _make_decode_ready call site: 00247 /src/vorbis/lib/vorbisfile.c:604
0 0 None 0 61 _vds_shared_init call site: 00283 /src/vorbis/lib/block.c:238
0 0 None 0 60 vorbis_synthesis call site: 00316 /src/vorbis/lib/synthesis.c:33
0 0 None 0 39 _fetch_headers call site: 00142 /src/vorbis/lib/vorbisfile.c:340

Runtime coverage analysis

Covered functions
134
Functions that are reachable but not covered
33
Reachable functions
122
Percentage of reachable functions covered
72.95%
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
vorbis/contrib/oss-fuzz/decode_fuzzer.cc 2
vorbis/lib/vorbisfile.c 24
oggframing.c 26
vorbis/lib/info.c 10
oggbitwise.c 4
vorbis/lib/sharedbook.c 11
vorbis/lib/psy.c 8
vorbis/lib/codebook.c 1
vorbis/lib/block.c 11
vorbis/lib/envelope.c 1
vorbis/lib/mdct.c 2
vorbis/lib/bitrate.c 1
vorbis/lib/smallft.c 4
vorbis/lib/synthesis.c 3
vorbis/lib/window.c 1
vorbis/lib/./os.h 3

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
mapping0_forward /src/vorbis/lib/mapping0.c 1 ['struct.vorbis_block *'] 3 0 1196 76 23 48 0 415 400
ov_time_seek_lap /src/vorbis/lib/vorbisfile.c 2 ['struct.OggVorbis_File *', 'N/A'] 7 0 20 3 2 121 0 992 169
drft_backward /src/vorbis/lib/smallft.c 2 ['struct.drft_lookup *', 'N/A'] 1 0 50 6 3 5 0 80 80
vorbis_analysis_blockout /src/vorbis/lib/block.c 2 ['struct.vorbis_dsp_state *', 'struct.vorbis_block *'] 6 0 650 58 21 17 0 106 70
vorbis_analysis_headerout /src/vorbis/lib/info.c 5 ['struct.vorbis_dsp_state *', 'struct.vorbis_comment *', 'struct.ogg_packet *', 'struct.ogg_packet *', 'struct.ogg_packet *'] 3 0 358 42 16 14 0 94 59
res0_inverse /src/vorbis/lib/res0.c 5 ['struct.vorbis_block *', 'char *', 'N/A', 'int *', 'int '] 2 0 95 13 5 8 0 63 57
vorbis_bitrate_addblock /src/vorbis/lib/bitrate.c 1 ['struct.vorbis_block *'] 1 0 914 123 43 5 0 65 45
res2_forward /src/vorbis/lib/res0.c 8 ['struct.oggpack_buffer *', 'struct.vorbis_block *', 'char *', 'int **', 'int *', 'int ', 'size_t **', 'int '] 3 0 155 17 6 8 0 70 44
vorbis_analysis_wrote /src/vorbis/lib/block.c 2 ['struct.vorbis_dsp_state *', 'int '] 1 0 295 27 10 5 0 42 40
vorbis_lpc_to_lsp /src/vorbis/lib/lsp.c 3 ['N/A', 'N/A', 'int '] 0 0 380 40 12 6 0 39 37

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

Functions statically reachable by fuzzers
64.0%
213 / 335
Cyclomatic complexity statically reachable by fuzzers
75.0%
1934 / 2592

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

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/vorbis/contrib/oss-fuzz/decode_fuzzer.cc ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/floor1.c [] []
/src/vorbis/lib/sharedbook.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/./scales.h [] []
/src/vorbis/lib/floor0.c [] []
/src/vorbis/lib/psy.c ['decode_fuzzer'] []
/src/vorbis/lib/lsp.c [] []
/src/vorbis/lib/window.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/codebook.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/synthesis.c ['decode_fuzzer'] ['decode_fuzzer']
/src/ogg/src/framing.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/vorbisfile.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/bitrate.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/lpc.c [] []
/src/vorbis/lib/res0.c [] []
/src/vorbis/lib/smallft.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/block.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/info.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/mapping0.c [] []
/src/vorbis/lib/./os.h ['decode_fuzzer'] []
/src/ogg/src/bitwise.c ['decode_fuzzer'] ['decode_fuzzer']
/src/vorbis/lib/envelope.c ['decode_fuzzer'] []
/src/vorbis/lib/mdct.c ['decode_fuzzer'] ['decode_fuzzer']

Directories in report

Directory
/src/vorbis/lib/
/src/vorbis/lib/./
/src/ogg/src/
/src/vorbis/contrib/oss-fuzz/