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

Table of contents

Project overview: libical
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: libical_fuzzer
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Fuzzer: libical_extended_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/libical_fuzzer.cc
Dictionary
Fuzzer function priority
/src/libical_extended_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: 2025-08-03

Project overview: libical

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
35.0%
528 / 1514
Cyclomatic complexity statically reachable by fuzzers
45.0%
3036 / 6796
Runtime code coverage of functions
27.0%
405 / 1514

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
libical_fuzzer /src/libical_fuzzer.cc 465 1098 31 30 5818 2618 libical_fuzzer.cc
libical_extended_fuzzer /src/libical_extended_fuzzer.cc 575 988 32 30 7005 3131 libical_extended_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: libical_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 0 904 49.7%
gold [1:9] 28 1.54%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 884 48.6%
All colors 1816 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
58 64 2 :

['ical_get_invalid_rrule_handling_setting', 'icalrecur_free_by']

58 319 icalrecurrencetype_new_from_string call site: 01628 /src/libical/src/libical/icalrecur.c:958
58 58 1 :

['icalrecur_free_by']

58 58 icalrecur_resize_by call site: 00514 /src/libical/src/libical/icalrecur.c:316
2 118 3 :

['icalmemory_strdup', 'icalmemory_free_buffer', '__errno_location']

2 118 icalattach_new_from_data call site: 01451 /src/libical/src/libical/icalattach.c:65
2 57 2 :

['icalmemory_free_buffer', '__errno_location']

2 57 icalattach_new_from_url call site: 01432 /src/libical/src/libical/icalattach.c:34
2 2 1 :

['get_zone_directory_builtin']

24 512 icaltimezone_parse_zone_tab call site: 00535 /src/libical/src/libical/icaltimezone.c:1665
2 2 1 :

['__errno_location']

2 13 icalvalue_set_caladdress call site: 01536 /src/libical/src/libical/icalderivedvalue.c:200
2 2 1 :

['__errno_location']

2 13 icalvalue_set_query call site: 01486 /src/libical/src/libical/icalderivedvalue.c:579
2 2 1 :

['__errno_location']

2 13 icalvalue_set_string call site: 01526 /src/libical/src/libical/icalderivedvalue.c:741
2 2 1 :

['__errno_location']

2 13 icalvalue_set_text call site: 00112 /src/libical/src/libical/icalderivedvalue.c:810
2 2 1 :

['__errno_location']

2 13 icalvalue_set_uid call site: 01726 /src/libical/src/libical/icalderivedvalue.c:879
2 2 1 :

['__errno_location']

2 13 icalvalue_set_uri call site: 01546 /src/libical/src/libical/icalderivedvalue.c:917
2 2 1 :

['__errno_location']

2 13 icalvalue_set_xmlreference call site: 01735 /src/libical/src/libical/icalderivedvalue.c:1017

Runtime coverage analysis

Covered functions
253
Functions that are reachable but not covered
213
Reachable functions
465
Percentage of reachable functions covered
54.19%
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/libical_fuzzer.cc 1
icalparser.c 20
icalerror.c 10
icalmemory.c 14
pvl.c 13
icalderivedparameter.c 9
icalparameter.c 10
icalstrarray.c 5
icalarray.c 10
icalenumarray.c 5
icalderivedproperty.c 37
icalproperty.c 16
icalderivedvalue.c 52
icalvalue.c 13
icaltime.c 22
icalattach.c 4
icalrecur.c 93
icalcomponent.c 19
icaltimezone.c 33
icaltz-util.c 11
/usr/include/x86_64-linux-gnu/bits/byteswap.h 2
icalperiod.c 4
icalduration.c 7
caldate.c 2
qsort_gen.c 2
/usr/include/x86_64-linux-gnu/bits/stdlib-bsearch.h 1
icaltypes.c 4
/usr/include/stdlib.h 1
/usr/include/x86_64-linux-gnu/bits/stdlib-float.h 1
icalenums.c 1

Fuzzer: libical_extended_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 0 731 31.7%
gold [1:9] 211 9.16%
yellow [10:29] 13 0.56%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 1346 58.4%
All colors 2301 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
2652 2658 6 :

['icaltimezone_compare_change_fn', 'icaltimezone_ensure_coverage', 'icaltimezone_changes_unlock', 'icalarray_element_at', 'icaltimezone_changes_lock', 'icaltimezone_find_nearby_change']

2652 2658 icaltimezone_get_utc_offset_of_utc_time call site: 00638 /src/libical/src/libical/icaltimezone.c:983
58 64 2 :

['ical_get_invalid_rrule_handling_setting', 'icalrecur_free_by']

58 319 icalrecurrencetype_new_from_string call site: 01629 /src/libical/src/libical/icalrecur.c:958
58 58 1 :

['icalrecur_free_by']

58 58 icalrecur_resize_by call site: 00515 /src/libical/src/libical/icalrecur.c:316
2 118 3 :

['icalmemory_strdup', 'icalmemory_free_buffer', '__errno_location']

2 118 icalattach_new_from_data call site: 01452 /src/libical/src/libical/icalattach.c:65
2 57 2 :

['icalmemory_free_buffer', '__errno_location']

2 57 icalattach_new_from_url call site: 01433 /src/libical/src/libical/icalattach.c:34
2 2 1 :

['get_zone_directory_builtin']

24 512 icaltimezone_parse_zone_tab call site: 00536 /src/libical/src/libical/icaltimezone.c:1665
2 2 1 :

['__errno_location']

2 13 icalvalue_set_caladdress call site: 01537 /src/libical/src/libical/icalderivedvalue.c:200
2 2 1 :

['__errno_location']

2 13 icalvalue_set_query call site: 01487 /src/libical/src/libical/icalderivedvalue.c:579
2 2 1 :

['__errno_location']

2 13 icalvalue_set_string call site: 01527 /src/libical/src/libical/icalderivedvalue.c:741
2 2 1 :

['__errno_location']

2 13 icalvalue_set_text call site: 00113 /src/libical/src/libical/icalderivedvalue.c:810
2 2 1 :

['__errno_location']

2 13 icalvalue_set_uid call site: 01727 /src/libical/src/libical/icalderivedvalue.c:879
2 2 1 :

['__errno_location']

2 13 icalvalue_set_uri call site: 01547 /src/libical/src/libical/icalderivedvalue.c:917

Runtime coverage analysis

Covered functions
406
Functions that are reachable but not covered
170
Reachable functions
575
Percentage of reachable functions covered
70.43%
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/libical_extended_fuzzer.cc 1
icalcomponent.c 32
icalparser.c 20
icalerror.c 10
icalmemory.c 15
pvl.c 15
icalderivedparameter.c 21
icalparameter.c 17
icalstrarray.c 5
icalarray.c 10
icalenumarray.c 5
icalderivedproperty.c 47
icalproperty.c 22
icalderivedvalue.c 63
icalvalue.c 34
icaltime.c 24
icalattach.c 7
icalrecur.c 99
icaltimezone.c 39
icaltz-util.c 11
/usr/include/x86_64-linux-gnu/bits/byteswap.h 2
icalperiod.c 5
icalduration.c 9
caldate.c 2
qsort_gen.c 2
/usr/include/x86_64-linux-gnu/bits/stdlib-bsearch.h 1
icaltypes.c 5
/usr/include/stdlib.h 1
/usr/include/x86_64-linux-gnu/bits/stdlib-float.h 1
icalenums.c 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
icalcomponent_merge_component /src/libical/src/libical/icalcomponent.c 2 ['N/A', 'N/A'] 22 0 143 33 11 542 0 3034 144
icalcomponent_foreach_recurrence /src/libical/src/libical/icalcomponent.c 5 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 40 0 437 82 31 498 0 2813 128
icaltimezone_truncate_vtimezone /src/libical/src/libical/icaltimezone.c 4 ['N/A', 'N/A', 'N/A', 'int'] 58 0 1192 216 78 483 0 2808 106
icalrestriction_check_component /src/libical/src/libical/icalrestriction.c 2 ['int', 'N/A'] 21 0 238 44 14 90 3 430 71
icalrecur_iterator_prev /src/libical/src/libical/icalrecur.c 2 ['N/A', 'N/A'] 57 0 179 42 12 473 0 2666 64
icalcomponent_set_due /src/libical/src/libical/icalcomponent.c 2 ['N/A', 'N/A'] 20 0 85 15 7 493 0 2751 40
icalvalue_compare /src/libical/src/libical/icalvalue.c 2 ['N/A', 'N/A'] 24 0 352 82 26 124 0 477 36

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

Functions statically reachable by fuzzers
40.0%
606 / 1514
Cyclomatic complexity statically reachable by fuzzers
53.0%
3609 / 6796

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/libical_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=['ical_get_invalid_rrule_handling_setting', 'set_zoneinfopath', 'icalvalue_set_utcoffset', 'icalcomponent_remove_component', 'icaltimezone_get_tznames_from_vtimezone', 'icalvalue_get_datetimeperiod', 'icalvalue_set_period', 'icalcomponent_remove_property', 'icalcomponent_get_next_component', 'icalcomponent_get_first_component']

/src/libical_extended_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=['icalrecurrencetype_day_position', 'ical_get_invalid_rrule_handling_setting', 'icaltime_day_of_week', 'icalcomponent_remove_component', 'icalvalue_new_from_string_with_error', 'icaltimezone_convert_time', 'parse_posix_zone', 'icalrecur_memdup', 'icaltzutil_fetch_timezone', 'icalarray_fswap']

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
icaltimezone_load_builtin_timezone 84 4 4.761% ['libical_extended_fuzzer', 'libical_fuzzer']
icalvalue_clone 75 26 34.66% ['libical_extended_fuzzer', 'libical_fuzzer']
icaltime_adjust 63 29 46.03% ['libical_extended_fuzzer', 'libical_fuzzer']
icaltimezone_get_utc_offset 82 11 13.41% ['libical_extended_fuzzer', 'libical_fuzzer']
icaltimezone_get_utc_offset_of_utc_time 59 9 15.25% ['libical_extended_fuzzer', 'libical_fuzzer']
icaltimezone_get_builtin_timezone_from_tzid 40 17 42.5% ['libical_extended_fuzzer']
icaltzutil_fetch_timezone 465 253 54.40% ['libical_extended_fuzzer', 'libical_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
[] []
/usr/include/x86_64-linux-gnu/bits/byteswap.h ['libical_fuzzer', 'libical_extended_fuzzer'] []
/src/libical/src/libical/icalcomponent.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalvalue.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icaltypes.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical_fuzzer.cc ['libical_fuzzer'] ['libical_fuzzer']
/src/libical/src/libical/icalperiod.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/caldate.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_extended_fuzzer']
/src/libical/src/libical/icalproperty.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalmemory.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalrestriction.c [] []
/src/libical/src/libical/icalattach.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalerror.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/qsort_gen.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_extended_fuzzer']
/src/libical/src/libical/icalenumarray.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalderivedproperty.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/usr/include/x86_64-linux-gnu/bits/stdlib-float.h ['libical_fuzzer', 'libical_extended_fuzzer'] []
/src/libical/src/libical/icalderivedvalue.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalparser.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical_extended_fuzzer.cc ['libical_extended_fuzzer'] ['libical_extended_fuzzer']
/src/libical/src/libical/icaltime.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalarray.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icaltz-util.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalrecur.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/pvl.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalenums.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalderivedparameter.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalparameter.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icaltimezone.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/usr/include/x86_64-linux-gnu/bits/stdlib-bsearch.h ['libical_fuzzer', 'libical_extended_fuzzer'] []
/usr/include/stdlib.h ['libical_fuzzer', 'libical_extended_fuzzer'] []
/src/libical/src/libical/icalstrarray.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']
/src/libical/src/libical/icalduration.c ['libical_fuzzer', 'libical_extended_fuzzer'] ['libical_fuzzer', 'libical_extended_fuzzer']

Directories in report

Directory
/usr/include/x86_64-linux-gnu/bits/
/usr/include/
/src/
/src/libical/src/libical/

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
libical_fuzzer fuzzerLogFile-0-DU0BHkF8iO.data fuzzerLogFile-0-DU0BHkF8iO.data.yaml libical_fuzzer.covreport
libical_extended_fuzzer fuzzerLogFile-0-7Fr4PWOzPS.data fuzzerLogFile-0-7Fr4PWOzPS.data.yaml libical_extended_fuzzer.covreport