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

Table of contents

Project overview: nbclassic
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: fuzz_cell
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Function call coverage
Function in each files in report
Report generation date: 2023-03-26

Project overview: nbclassic

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
1.41%
18/1277
Cyclomatic complexity statically reachable by fuzzers
1.42%
58/4089
Runtime code coverage of functions
17.0%
223 / 1277

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
fuzz_cell /src/fuzz_cell.py 20 1271 3 6 10 61 fuzz_cell.py

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: fuzz_cell

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 3 9.09%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 30 90.9%
All colors 33 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
1 4 nbformat.v4.nbbase.new_markdown_cell call site: 00004 nbformat.corpus.words.generate_corpus_id
1 6 nbformat.corpus.words.generate_corpus_id call site: 00006 _struct.Struct.__init__
1 10 nbformat.notebooknode.NotebookNode.update call site: 00010 .hasattr

Runtime coverage analysis

Covered functions
102
Functions that are reachable but not covered
15
Reachable functions
20
Percentage of reachable functions covered
25.0%
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.
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
/ 1
...fuzz_cell 4
nbformat.v4.nbbase 4
nbformat.corpus.words 1
nbformat.notebooknode 4
nbclassic.bundler.tools 7

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
nbformat.write nbformat 5 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 4 0 5 3 4 55 1 193 178
nbclassic.nbextensions.InstallNBExtensionApp.install_extensions nbclassic.nbextensions 1 ['N/A'] 2 0 2 3 4 53 1 179 164
nbclassic.jstest.run_jstestall nbclassic.jstest 1 ['N/A'] 2 0 24 7 6 47 2 149 134
nbclassic.nbextensions.UninstallNBExtensionApp.start nbclassic.nbextensions 1 ['N/A'] 3 0 5 3 4 54 0 181 107
nbformat.v3.nbpy.PyReader.to_notebook nbformat.v3.nbpy 3 ['N/A', 'N/A', 'N/A'] 2 0 8 14 9 26 2 97 88
nbclassic.jstest.JSController.setup nbclassic.jstest 1 ['N/A'] 2 0 10 4 5 33 0 105 75
nbclassic.tree.handlers.TreeHandler.get nbclassic.tree.handlers 2 ['N/A', 'N/A'] 1 0 4 4 5 21 0 69 63
nbclassic.tests.end_to_end.utils.NotebookFrontend.add_cell nbclassic.tests.end_to_end.utils 4 ['N/A', 'N/A', 'N/A', 'N/A'] 3 0 4 2 4 18 4 64 61
nbformat.v4.convert.upgrade nbformat.v4.convert 3 ['N/A', 'N/A', 'N/A'] 3 0 6 8 6 23 0 80 56
nbclassic.bundler.tools.expand_references nbclassic.bundler.tools 2 ['N/A', 'N/A'] 0 0 12 14 9 22 2 75 54

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

Functions statically reachable by fuzzers
24.1%
308/1277
Cyclomatic complexity statically reachable by fuzzers
25.2%
1032 / 4089

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
nbclassic.bundler.tools.expand_references 50 0 0.0% []
nbformat.v4.convert.upgrade 35 0 0.0% []
re.search 298 39 13.08% []
d.get 88 27 30.68% []
os.chmod 90 30 33.33% []
nbformat.v3.nbbase.new_output 38 0 0.0% []
nbformat.v3.nbpy.PyReader.to_notebook 57 0 0.0% []
nbformat.v3.nbpy.PyWriter.writes 44 7 15.90% []
platform.platform 130 34 26.15% []
nbformat.v2.nbpy.PyReader.to_notebook 33 0 0.0% []
nbformat.v2.nbpy.PyWriter.writes 31 7 22.58% []
traitlets.Instance._write_secret_file 1579 160 10.13% []
jupyter_core.paths.jupyter_runtime_dir 441 53 12.01% []
jupyter_core.application.JupyterApp.log.debug 163 61 37.42% []
ipython_genutils.py3compat.cast_unicode_py2.replace 196 53 27.04% []
ipython_genutils.tempdir.TemporaryDirectory 77 17 22.07% []
p.wait 54 9 16.66% []
inspect.isawaitable 669 178 26.60% []
info.update 37 20 54.05% []
a.startswith 242 36 14.87% []

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
[] []
time [] []
nbclassic.tests.end_to_end.test_buffering [] []
sqlite3 [] []
testpath [] []
nbclassic.tests.end_to_end.test_save_readonly_as [] []
nbclassic.tests.end_to_end.test_move_multiselection [] []
jupyter_server [] []
argparse [] []
nbformat._version [] []
nbformat._struct [] []
nbformat.v1.rwbase [] []
nbclassic.tests.end_to_end.conftest [] []
nbclassic.tests.end_to_end.test_find_and_replace [] []
nbclassic.tests.end_to_end.manual_test_prototyper [] []
atheris [] []
pysqlite2 [] []
nbclassic.tests.end_to_end.test_multiselect_toggle [] []
gettext [] []
nbformat [] []
nbclassic.shim_notebook [] []
nbclassic.tests.end_to_end.test_notifications [] []
nbformat.v4.rwbase [] []
warnings [] []
nbclassic.tests.end_to_end.test_clipboard_multiselect [] []
nbclassic.terminal.handlers [] []
playwright [] []
nbclassic.tests.end_to_end [] []
pytest [] []
nbformat.corpus.words ['fuzz_cell'] []
json [] []
nbclassic.tests.end_to_end.test_dualmode_clipboard [] []
nbformat.v3.convert [] []
nbclassic.terminal [] []
nbformat.v3.rwbase [] []
nbformat.v2.convert [] []
copy [] []
nbclassic.nbextensions [] []
jupyter_core [] []
datetime [] []
nbclassic.bundler.zip_bundler [] []
_struct [] []
nbformat.sign [] []
nbformat.validator [] []
...fuzz_cell ['fuzz_cell'] []
nbclassic.i18n [] []
nbformat.v2.rwbase [] []
textwrap [] []
requests [] []
read [] []
nbclassic.tests.end_to_end.test_multiselect [] []
nbclassic.tests.end_to_end.test_dualmode_execute [] []
importlib [] []
nbclassic.tests.end_to_end.test_dualmode_markdown [] []
nbclassic.tests.end_to_end.test_execute_code [] []
nbformat.v2.nbbase [] []
nbclassic.edit [] []
nbformat.v4 [] []
inspect [] []
nbclassic.bundler.tools ['fuzz_cell'] []
nbclassic.tests.end_to_end.test_deletecell [] []
nbclassic.tests.end_to_end.test_merge_cells [] []
base64 [] []
nbclassic.bundler.bundlerextensions [] []
os [] []
nbclassic.tree [] []
nbclassic.tests.end_to_end.test_save_as_notebook [] []
platform [] []
re [] []
nbformat.v3 [] []
nbclassic.serverextensions [] []
nbclassic.tests.end_to_end.test_interrupt [] []
nbformat.v1.convert [] []
uuid [] []
nbclassic.jstest [] []
nbclassic.tests.end_to_end.utils [] []
jsonschema [] []
nbclassic.tests.end_to_end.test_display_isolation [] []
nbclassic._version [] []
nbformat.v4.convert [] []
nbclassic.tests.end_to_end.test_shutdown [] []
nbclassic.tests.end_to_end.test_prompt_numbers [] []
nbclassic.traits [] []
nbformat.reader [] []
nbclassic.transutils [] []
zipfile [] []
asyncio [] []
nbclassic.tree.handlers [] []
nbclassic.tests.end_to_end.test_dualmode_insertcell [] []
[] []
reads [] []
nbformat.v2.nbjson [] []
tarfile [] []
unittest [] []
hmac [] []
nbformat.v4.nbbase ['fuzz_cell'] []
nbclassic.shim [] []
ast [] []
nbconvert [] []
traitlets [] []
nbclassic.tests.end_to_end.test_undelete [] []
nbclassic.tests [] []
nbformat.current [] []
nbformat.v2 [] []
nbformat.v1.nbbase [] []
sys [] []
nbclassic.notebook.handlers [] []
nbformat.v2.nbpy [] []
nbclassic.__main__ [] []
nbformat.notebooknode ['fuzz_cell'] []
notebook_shim [] []
io [] []
nbformat.v3.nbjson [] []
nbformat.v3.nbbase [] []
nbclassic.bundler.handlers [] []
nbformat.json_compat [] []
nbclassic.tests.end_to_end.test_dualmode_arrows [] []
collections [] []
nbformat._imports [] []
shutil [] []
nbformat.sentinel [] []
nbformat.converter [] []
nbclassic.notebookapp [] []
nbclassic.tests.end_to_end.test_kernel_menu [] []
nbformat.v3.nbpy [] []
fnmatch [] []
nbclassic.extensions [] []
threading [] []
importlib_metadata [] []
fastjsonschema [] []
tempfile [] []
nbclassic.config_manager [] []
nbformat.v1.nbjson [] []
nbformat.v2.nbxml [] []
nbclassic.tests.end_to_end.test_save [] []
nbclassic [] []
nbclassic.bundler.__main__ [] []
nbformat.v1 [] []
nbformat.corpus [] []
nbclassic.bundler.tarball_bundler [] []
urllib [] []
nbclassic.tests.end_to_end.test_display_image [] []
nbclassic.tests.end_to_end.test_dashboard_nav [] []
traceback [] []
nbclassic.bundler [] []
glob [] []
nbclassic.notebook [] []
subprocess [] []
nbformat.v4.nbjson [] []
ipython_genutils [] []
nbclassic.tests.end_to_end.test_dualmode_cellmode [] []
nbclassic.edit.handlers [] []
nbformat.warnings [] []
nbclassic._sysinfo [] []
nbclassic.tests.end_to_end.test_markdown [] []

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
fuzz_cell fuzzerLogFile-fuzz_cell.data fuzzerLogFile-fuzz_cell.data.yaml all_cov.json

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.

Function in each files in report

Target sink Callsite location Reached by fuzzer Function call path Covered by fuzzer Possible branch blockers