def test_old_style_signing_cert_attr_mismatch(with_issser):
if with_issser:
# this file has an old-style signing cert attr with issuerSerial
fname = 'pades-with-old-style-signing-cert-attr-issser.pdf'
else:
fname = 'pades-with-old-style-signing-cert-attr.pdf'
with open(os.path.join(PDF_DATA_DIR, fname), 'rb') as f:
r = PdfFileReader(f)
s = r.embedded_signatures[0]
signer_info = s.signer_info
digest = s.compute_digest()
# signer1-long has the same key as signer1
alt_cert = TESTING_CA.get_cert(CertLabel('signer1-long'))
signer_info['sid'] = {
'issuer_and_serial_number':
cms.IssuerAndSerialNumber({
'issuer': alt_cert.issuer,
'serial_number': alt_cert.serial_number
})
}
with pytest.raises(SignatureValidationError,
match="Signing certificate attribute does not match "):
validate_sig_integrity(signer_info,
alt_cert,
expected_content_type='data',
actual_digest=digest)
def test_signing_cert_attr_duplicated():
output = _tamper_with_signed_attrs('signing_certificate_v2',
resign=True,
duplicate=True)
r = PdfFileReader(output)
emb = r.embedded_signatures[0]
digest = emb.compute_digest()
with pytest.raises(SignatureValidationError,
match="Wrong cardinality for signing cert"):
validate_sig_integrity(emb.signer_info, emb.signer_cert, 'data',
digest)
def test_no_content_type():
output = _tamper_with_signed_attrs('content_type',
delete=True,
resign=True)
r = PdfFileReader(output)
emb = r.embedded_signatures[0]
digest = emb.compute_digest()
with pytest.raises(SignatureValidationError):
validate_sig_integrity(emb.signer_info, emb.signer_cert, 'data',
digest)
def test_cms_algorithm_protection(replacement_value):
output = _tamper_with_signed_attrs('cms_algorithm_protection',
duplicate=replacement_value is None,
replace_with=replacement_value,
resign=True)
r = PdfFileReader(output)
emb = r.embedded_signatures[0]
digest = emb.compute_digest()
with pytest.raises(SignatureValidationError, match='.*CMS.*'):
validate_sig_integrity(emb.signer_info, emb.signer_cert, 'data',
digest)
def test_wrong_content_type():
# delete the (signed) CMSAlgorithmProtection attribute
# this should invalidate the signature
output = _tamper_with_signed_attrs('content_type',
replace_with='enveloped_data',
resign=True)
r = PdfFileReader(output)
emb = r.embedded_signatures[0]
digest = emb.compute_digest()
with pytest.raises(SignatureValidationError):
validate_sig_integrity(emb.signer_info, emb.signer_cert, 'data',
digest)
def test_signing_cert_attr_malformed_issuer():
from asn1crypto import x509
cert = TESTING_CA.get_cert(CertLabel('signer1'))
bogus_attr = as_signing_certificate_v2(cert)
bogus_attr['certs'][0]['issuer_serial']['issuer'][0] = x509.GeneralName(
{'dns_name': 'www.example.com'})
output = _tamper_with_signed_attrs('signing_certificate_v2',
resign=True,
replace_with=bogus_attr)
r = PdfFileReader(output)
emb = r.embedded_signatures[0]
digest = emb.compute_digest()
with pytest.raises(SignatureValidationError,
match="Signing certificate attribute does not match "):
validate_sig_integrity(emb.signer_info, emb.signer_cert, 'data',
digest)
def _signer_sanity_check(signer):
digest = hashlib.sha256(b'Hello world!').digest()
with pytest.deprecated_call():
sig = signer.sign(digest, digest_algorithm='sha256')
from pyhanko.sign.general import validate_sig_integrity
intact, valid = validate_sig_integrity(
sig['content']['signer_infos'][0], cert=signer.signing_cert,
expected_content_type='data', actual_digest=digest
)
assert intact and valid
def test_signed_attrs_tampering():
# delete the (signed) CMSAlgorithmProtection attribute
# this should invalidate the signature
output = _tamper_with_signed_attrs('cms_algorithm_protection', delete=True)
r = PdfFileReader(output)
emb = r.embedded_signatures[0]
digest = emb.compute_digest()
intact, valid = validate_sig_integrity(emb.signer_info, emb.signer_cert,
'data', digest)
# "intact" refers to the messageDigest attribute, which we didn't touch
assert intact and not valid