load_pem_private_key fails with unexpected OpenSSL error depending on password #8563
Description
I have a test that creates an encrypted rsa key and then tries to load and decrypt it with load_pem_private_key, using an invalid password and asserting the error message "Bad decrypt. Incorrect password?".
Every now and then my test fails, because I get a different error message, i.e.: (pretty printed for better readability)
('Could not deserialize key data. The data may be in an incorrect format, it '
'may be encrypted with an unsupported algorithm, or it may be an unsupported '
'key type (e.g. EC curves with explicit parameters).',
[_OpenSSLErrorWithText(code=503841036, lib=60, reason=524556, reason_text=b'error:1E08010C:DECODER routines::unsupported'),
_OpenSSLErrorWithText(code=109052027, lib=13, reason=123, reason_text=b'error:0680007B:asn1 encoding routines::header too long'),
_OpenSSLErrorWithText(code=109052006, lib=13, reason=102, reason_text=b'error:06800066:asn1 encoding routines::bad object header'),
_OpenSSLErrorWithText(code=109576458, lib=13, reason=524554, reason_text=b'error:0688010A:asn1 encoding routines::nested asn1 error'),
_OpenSSLErrorWithText(code=109052027, lib=13, reason=123, reason_text=b'error:0680007B:asn1 encoding routines::header too long'),
_OpenSSLErrorWithText(code=109052006, lib=13, reason=102, reason_text=b'error:06800066:asn1 encoding routines::bad object header'),
_OpenSSLErrorWithText(code=109576458, lib=13, reason=524554, reason_text=b'error:0688010A:asn1 encoding routines::nested asn1 error')])
The key parses successfully when providing the correct password, and also raises the expected error when providing a different invalid password.
The following script can be used to reproduce the issue. Key is hard-coded, because the issue does not occur for every key created with the commented out snippet.
Reproducer
from cryptography.hazmat.primitives.serialization import load_pem_private_key
# # Create encrypted RSA PEM
# from cryptography.hazmat.backends import default_backend
# from cryptography.hazmat.primitives import serialization
# from cryptography.hazmat.primitives.asymmetric import rsa
#
# key = rsa.generate_private_key(
# public_exponent=65537, key_size=3072, backend=default_backend()
# )
# encrypted_rsa_key = key.private_bytes(
# encoding=serialization.Encoding.PEM,
# format=serialization.PrivateFormat.TraditionalOpenSSL,
# encryption_algorithm=serialization.BestAvailableEncryption(b"pw"),
# )
# Not every key triggers the unexpected error below, but this one does:
encrypted_rsa_key = b"-----BEGIN RSA PRIVATE KEY-----\nProc-Type: 4,ENCRYPTED\nDEK-Info: AES-256-CBC,6EF2C95AF143341584114A13ED0A8C06\n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\n-----END RSA PRIVATE KEY-----"
# Parse and decrypt successfully with valid password
load_pem_private_key(encrypted_rsa_key, b"pw")
# Fail with invalid password and expected error message: "Bad decrypt. Incorrect password?"
load_pem_private_key(encrypted_rsa_key, b"not pw")
# Fail with different invalid password and unexpected error message: "Could not deserialize key data..."
load_pem_private_key(encrypted_rsa_key, b"bad pw")Environment
$ python --version
Python 3.10.9
$ pip list
Package Version
------------ -------
cffi 1.15.1
cryptography 39.0.2
pip 23.0.1
pycparser 2.21
setuptools 67.4.0
wheel 0.38.4