Fuzz introspector
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Project coverage

Table of contents

Project overview: paramiko
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: fuzz_packetizer
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: paramiko

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
3.59%
109/3037
Cyclomatic complexity statically reachable by fuzzers
3.6%
352/9770
Runtime code coverage of functions
64.0%
1945 / 3037

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
fuzz_packetizer ./fuzz_packetizer.py 116 3018 9 25 74 370 fuzz_packetizer.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_packetizer

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 0 171 57.9%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 124 42.0%
All colors 295 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
95 112 paramiko.message.Message.asbytes call site: 00112 paramiko.dsskey.DSSKey.asbytes
18 243 paramiko.packet.Packetizer._build_packet call site: 00243 cryptography.hazmat.primitives.ciphers.base._CipherContext.update
9 102 paramiko.util.b call site: 00102 paramiko.rsakey.RSAKey.asbytes
6 31 cryptography.hazmat.backends.openssl.ciphers._CipherContext.__init__ call site: 00031 .isinstance
6 223 ...paramiko.tests.fuzz_packetizer.TestOneInput call site: 00223 paramiko.message.Message.add
5 0 EP call site: 00000 paramiko.packet.Packetizer.__init__
5 43 cryptography.hazmat.backends.openssl.ciphers._CipherContext.__init__ call site: 00043 cryptography.hazmat.backends.openssl.backend.Backend.openssl_assert
4 290 paramiko.packet.Packetizer.send_message call site: 00290 paramiko.packet.Packetizer._log
3 230 paramiko.message.Message.add_bytes call site: 00230 paramiko.common.byte_chr
3 285 paramiko.packet.Packetizer.write_all call site: 00285 paramiko.packet.first_arg
2 27 cryptography.hazmat.backends.openssl.ciphers._CipherContext.__init__ call site: 00027 cryptography.hazmat.backends.openssl.backend.Backend.openssl_version_text
2 39 cryptography.hazmat.backends.openssl.backend.Backend.openssl_assert call site: 00039 cryptography.hazmat.bindings._rust.openssl.capture_error_stack

Runtime coverage analysis

Covered functions
413
Functions that are reachable but not covered
72
Reachable functions
116
Percentage of reachable functions covered
37.93%
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
...paramiko.tests.fuzz_packetizer 24
paramiko.packet 23
cryptography.hazmat.primitives.ciphers.base 10
cryptography.hazmat.primitives.ciphers.modes 5
cryptography.hazmat.backends.openssl.backend 9
cryptography.hazmat.backends.openssl.ciphers 13
cryptography.hazmat.bindings.openssl.binding 1
cryptography.hazmat.primitives.ciphers.algorithms 3
cryptography.utils 1
paramiko.common 3
paramiko.message 15
paramiko.util 18
paramiko.rsakey 4
paramiko.dsskey 4
paramiko.ecdsakey 9
cryptography.hazmat.backends.openssl.rsa 4
cryptography.hazmat.primitives.asymmetric.rsa 1
cryptography.hazmat.backends.openssl.ec 4
cryptography.hazmat.primitives.asymmetric.ec 1
cryptography.hazmat.backends.openssl.dh 5
cryptography.hazmat.primitives.asymmetric.dh 2
cryptography.hazmat.backends.openssl.dsa 5
cryptography.hazmat.primitives.asymmetric.dsa 1
paramiko.ed25519key 5

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
paramiko.hostkeys.HostKeys.load paramiko.hostkeys 2 ['N/A', 'N/A'] 5 0 3 4 5 232 6 767 587
paramiko.client.SSHClient.connect paramiko.client 23 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 8 0 10 20 11 179 0 575 355
paramiko.transport.Transport.run paramiko.transport 1 ['N/A'] 9 0 40 22 12 145 0 482 194
paramiko.sftp_client.SFTPClient.putfo paramiko.sftp_client 6 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 10 0 2 2 4 133 1 449 158
cryptography.hazmat.primitives.serialization.ssh.SSHCertificateBuilder.sign cryptography.hazmat.primitives.serialization.ssh 2 ['N/A', 'N/A'] 4 0 33 9 7 101 0 322 143
paramiko.auth_handler.AuthHandler._parse_service_accept paramiko.auth_handler 2 ['N/A', 'N/A'] 8 0 30 14 9 109 0 354 124
paramiko.rsakey.RSAKey.verify_ssh_sig paramiko.rsakey 3 ['N/A', 'N/A', 'N/A'] 4 0 1 3 4 92 0 291 118

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

Functions statically reachable by fuzzers
19.1%
582/3037
Cyclomatic complexity statically reachable by fuzzers
19.8%
1937 / 9770

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
paramiko.packet.Packetizer.read_all 31 0 0.0% []
paramiko.packet.Packetizer.read_message 65 0 0.0% []
cryptography.hazmat.backends.openssl.backend.Backend._evp_pkey_to_private_key 38 0 0.0% []
cryptography.hazmat.backends.openssl.backend.Backend._evp_pkey_to_public_key 40 0 0.0% []
cryptography.hazmat.backends.openssl.backend.Backend._private_key_bytes 52 0 0.0% []
cryptography.hazmat.backends.openssl.backend.Backend.load_pkcs12 47 0 0.0% []
cryptography.hazmat.backends.openssl.backend.Backend.serialize_key_and_certificates_to_pkcs12 76 0 0.0% []
cryptography.hazmat.backends.openssl.rsa._enc_dec_rsa_pkey_ctx 35 0 0.0% []
cryptography.hazmat.primitives.serialization.ssh.load_ssh_private_key 54 0 0.0% []
cryptography.hazmat.primitives.serialization.ssh._serialize_ssh_private_key 52 5 9.615% []
cryptography.hazmat.primitives.serialization.ssh._load_ssh_public_identity 56 0 0.0% []
cryptography.hazmat.primitives.serialization.ssh.SSHCertificateBuilder.sign 77 0 0.0% []
cryptography.hazmat.backends.openssl.aead._decrypt 35 0 0.0% []
paramiko.sftp_attr.SFTPAttributes.__str__ 38 0 0.0% []
re.search 73 21 28.76% []
paramiko.sftp_server.SFTPServer._check_file 49 0 0.0% []
paramiko.sftp_server.SFTPServer._process 121 1 0.826% []
paramiko.channel.Channel._handle_request 69 0 0.0% []
paramiko.transport.Transport.__init__ 84 0 0.0% []
paramiko.transport.Transport.open_channel 48 0 0.0% []
paramiko.transport.Transport.run 103 0 0.0% []
paramiko.transport.Transport._send_kex_init 33 0 0.0% []
paramiko.transport.Transport._parse_kex_init 74 0 0.0% []
paramiko.transport.Transport._activate_outbound 34 0 0.0% []
paramiko.transport.Transport._parse_channel_open 81 0 0.0% []
paramiko.config.SSHConfig._does_match 33 0 0.0% []
paramiko.auth_handler.AuthHandler._finalize_pubkey_algorithm 33 0 0.0% []
paramiko.auth_handler.AuthHandler._parse_service_accept 80 0 0.0% []
paramiko.auth_handler.AuthHandler._parse_userauth_request 111 0 0.0% []
paramiko.ecdsakey.ECDSAKey.__init__ 32 0 0.0% []
paramiko.ed25519key.Ed25519Key._parse_signing_key_data 49 0 0.0% []
paramiko.pkey.PKey._read_private_key_pem 33 0 0.0% []
paramiko.pkey.PKey._read_private_key_openssh 35 0 0.0% []
paramiko.ber.BER.decode_next 32 0 0.0% []
nacl.signing.SigningKey 89 36 40.44% []
paramiko.kex_gss.KexGSSGroup1._parse_kexgss_init 33 0 0.0% []
paramiko.kex_gss.KexGSSGex._parse_kexgss_gex_init 39 0 0.0% []
paramiko.kex_gss.KexGSSGex._parse_kexgss_complete 31 0 0.0% []
paramiko.file.BufferedFile.read 39 0 0.0% []
paramiko.file.BufferedFile.readline 53 0 0.0% []
paramiko.client.SSHClient.connect 64 0 0.0% []
paramiko.client.SSHClient._auth 88 0 0.0% []

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
[] []
cryptography.hazmat.primitives.twofactor.totp [] []
cryptography.hazmat.backends.openssl.backend ['fuzz_packetizer'] []
cryptography.hazmat.backends.openssl [] []
cryptography.hazmat.primitives.serialization.ssh [] []
cryptography.__about__ [] []
cryptography.hazmat.backends.openssl.poly1305 [] []
cryptography.x509 [] []
cryptography.hazmat.primitives.hashes [] []
cryptography.hazmat.bindings.openssl.binding ['fuzz_packetizer'] []
...paramiko.tests.fuzz_packetizer ['fuzz_packetizer'] []
cryptography.hazmat.primitives._cipheralgorithm [] []
cryptography.hazmat.backends.openssl.ciphers ['fuzz_packetizer'] []
paramiko.sftp_server [] []
shlex [] []
paramiko.ber [] []
paramiko.agent [] []
paramiko.proxy [] []
cryptography.hazmat.primitives.asymmetric.dh ['fuzz_packetizer'] []
paramiko.compress [] []
paramiko.kex_gex [] []
cryptography.hazmat.primitives.asymmetric.types [] []
cryptography.hazmat.primitives.constant_time [] []
cryptography.hazmat.backends.openssl.cmac [] []
datetime [] []
paramiko.ssh_exception [] []
cryptography.hazmat.backends.openssl.dh ['fuzz_packetizer'] []
cryptography.hazmat.backends.openssl.ed448 [] []
cryptography.hazmat.primitives.asymmetric.ec ['fuzz_packetizer'] []
paramiko.sftp_si [] []
cryptography.hazmat.primitives.ciphers.base ['fuzz_packetizer'] []
cryptography.hazmat.primitives.asymmetric.padding [] []
paramiko.message ['fuzz_packetizer'] []
paramiko.dsskey ['fuzz_packetizer'] []
cryptography.hazmat.backends.openssl.ec ['fuzz_packetizer'] []
cryptography.x509.certificate_transparency [] []
threading [] []
cryptography.x509.ocsp [] []
cryptography.hazmat.backends.openssl.dsa ['fuzz_packetizer'] []
paramiko.server [] []
paramiko.ecdsakey ['fuzz_packetizer'] []
cryptography.hazmat.primitives.twofactor [] []
cryptography.hazmat.primitives.asymmetric.dsa ['fuzz_packetizer'] []
getpass [] []
invoke [] []
cryptography.x509.name [] []
cryptography.hazmat.primitives.kdf.hkdf [] []
math [] []
urllib [] []
collections [] []
paramiko.packet ['fuzz_packetizer'] []
cryptography.hazmat.backends.openssl.x448 [] []
cryptography.x509.extensions [] []
sspi [] []
cryptography.x509.base [] []
traceback [] []
sys [] []
cryptography.hazmat.backends.openssl.hashes [] []
socket [] []
email [] []
cryptography.hazmat._oid [] []
paramiko.sftp_file [] []
itertools [] []
paramiko.kex_curve25519 [] []
cryptography.hazmat.primitives.ciphers [] []
fcntl [] []
cryptography.hazmat.primitives.asymmetric.ed25519 [] []
cryptography.hazmat.backends.openssl.rsa ['fuzz_packetizer'] []
paramiko.kex_group1 [] []
cryptography.hazmat.primitives.poly1305 [] []
cryptography.hazmat.primitives._asymmetric [] []
paramiko.pkey [] []
paramiko.primes [] []
paramiko.win_pageant [] []
cryptography.hazmat.primitives.keywrap [] []
cryptography.hazmat.backends.openssl.aead [] []
weakref [] []
paramiko.kex_group14 [] []
time [] []
cryptography.hazmat.bindings [] []
cryptography.x509.oid [] []
atheris [] []
cryptography.hazmat.primitives.kdf.kbkdf [] []
cryptography.hazmat.primitives.asymmetric.x25519 [] []
paramiko.kex_group16 [] []
cryptography.hazmat.primitives.hmac [] []
paramiko.ssh_gss [] []
cryptography.hazmat.primitives.cmac [] []
cryptography.hazmat.primitives.kdf.concatkdf [] []
paramiko.pipe [] []
types [] []
cryptography [] []
cryptography.hazmat.bindings.openssl [] []
io [] []
cryptography.hazmat.primitives.twofactor.hotp [] []
cryptography.hazmat.primitives [] []
paramiko.transport [] []
[] []
paramiko.win_openssh [] []
cryptography.hazmat.primitives.kdf.x963kdf [] []
paramiko.sftp [] []
cryptography.hazmat.primitives.asymmetric.utils [] []
typing [] []
cryptography.exceptions [] []
cryptography.hazmat.primitives.ciphers.modes ['fuzz_packetizer'] []
paramiko.channel [] []
paramiko.kex_ecdh_nist [] []
paramiko._winapi [] []
pyasn1 [] []
cryptography.hazmat.backends.openssl.decode_asn1 [] []
atexit [] []
paramiko [] []
warnings [] []
paramiko.rsakey ['fuzz_packetizer'] []
platform [] []
loop [] []
cryptography.hazmat.backends.openssl.hmac [] []
inspect [] []
cryptography.hazmat.primitives.serialization [] []
cryptography.hazmat.backends [] []
paramiko.sftp_client [] []
cryptography.hazmat.primitives.asymmetric.ed448 [] []
zlib [] []
cryptography.hazmat.primitives.kdf [] []
paramiko.kex_gss [] []
paramiko.common ['fuzz_packetizer'] []
cryptography.hazmat.bindings.openssl._conditional [] []
hashlib [] []
cryptography.hazmat.primitives.serialization.pkcs7 [] []
binascii [] []
stat [] []
paramiko.util ['fuzz_packetizer'] []
cryptography.hazmat.primitives._serialization [] []
os [] []
cryptography.hazmat.primitives.ciphers.aead [] []
bcrypt [] []
paramiko.sftp_handle [] []
functools [] []
cryptography.hazmat.backends.openssl.ed25519 [] []
gssapi [] []
struct [] []
cryptography.hazmat.primitives.asymmetric.x448 [] []
select [] []
paramiko.hostkeys [] []
array [] []
subprocess [] []
cryptography.hazmat.primitives.ciphers.algorithms ['fuzz_packetizer'] []
cryptography.hazmat.backends.openssl.utils [] []
cryptography.hazmat.primitives.serialization.base [] []
paramiko._version [] []
cryptography.hazmat [] []
hmac [] []
cryptography.hazmat.primitives.kdf.pbkdf2 [] []
fnmatch [] []
re [] []
cryptography.hazmat.primitives.padding [] []
cryptography.x509.general_name [] []
paramiko.client [] []
cryptography.hazmat.primitives.asymmetric [] []
logging [] []
_thread [] []
cryptography.hazmat.primitives.asymmetric.rsa ['fuzz_packetizer'] []
cryptography.utils ['fuzz_packetizer'] []
paramiko.ed25519key ['fuzz_packetizer'] []
paramiko.sftp_attr [] []
paramiko.config [] []
cryptography.hazmat.bindings._rust [] []
cryptography.fernet [] []
cryptography.hazmat.primitives.kdf.scrypt [] []
base64 [] []
tempfile [] []
cryptography.hazmat.primitives.serialization.pkcs12 [] []
paramiko.buffered_pipe [] []
paramiko.auth_handler [] []
paramiko.file [] []

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_packetizer fuzzerLogFile-fuzz_packetizer.data fuzzerLogFile-fuzz_packetizer.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