def _tamper_with_sig_obj(tamper_fun):
input_buf = BytesIO(MINIMAL)
w = IncrementalPdfFileWriter(input_buf)
md_algorithm = 'sha256'
cms_writer = cms_embedder.PdfCMSEmbedder().write_cms(
field_name='Signature', writer=w
)
next(cms_writer)
sig_obj = signers.SignatureObject(bytes_reserved=8192)
cms_writer.send(cms_embedder.SigObjSetup(sig_placeholder=sig_obj))
tamper_fun(w, sig_obj)
prep_document_hash, output = cms_writer.send(
cms_embedder.SigIOSetup(md_algorithm=md_algorithm, in_place=True)
)
signer: signers.SimpleSigner = signers.SimpleSigner(
signing_cert=FROM_CA.signing_cert, signing_key=FROM_CA.signing_key,
cert_registry=FROM_CA.cert_registry,
signature_mechanism=SignedDigestAlgorithm({
'algorithm': 'rsassa_pkcs1v15'
})
)
with pytest.deprecated_call():
# noinspection PyDeprecation
cms_obj = signer.sign(
data_digest=prep_document_hash.document_digest,
digest_algorithm=md_algorithm,
)
cms_writer.send(cms_obj)
return output
async def test_sign_weak_sig_digest():
# We have to jump through some hoops to put together a signature
# where the signing method's digest is not the same as the "external"
# digest. This is intentional, since it's bad practice.
input_buf = BytesIO(MINIMAL)
w = IncrementalPdfFileWriter(input_buf)
cms_writer = cms_embedder.PdfCMSEmbedder().write_cms(
field_name='Signature', writer=w
)
next(cms_writer)
timestamp = datetime.now(tz=tzlocal.get_localzone())
sig_obj = signers.SignatureObject(timestamp=timestamp, bytes_reserved=8192)
external_md_algorithm = 'sha256'
cms_writer.send(cms_embedder.SigObjSetup(sig_placeholder=sig_obj))
prep_digest, output = cms_writer.send(
cms_embedder.SigIOSetup(md_algorithm=external_md_algorithm, in_place=True)
)
signer = signers.SimpleSigner(
signing_cert=TESTING_CA.get_cert(CertLabel('signer1')),
signing_key=TESTING_CA.key_set.get_private_key(KeyLabel('signer1')),
cert_registry=SimpleCertificateStore.from_certs([ROOT_CERT,
INTERM_CERT])
)
cms_obj = await signer.async_sign(
data_digest=prep_digest.document_digest,
digest_algorithm=external_md_algorithm,
signed_attr_settings=PdfCMSSignedAttributes(signing_time=timestamp)
)
si_obj: cms.SignerInfo = cms_obj['content']['signer_infos'][0]
bad_algo = SignedDigestAlgorithm({'algorithm': 'md5_rsa'})
si_obj['signature_algorithm'] = signer.signature_mechanism = bad_algo
attrs = si_obj['signed_attrs']
cms_prot = find_cms_attribute(attrs, 'cms_algorithm_protection')[0]
cms_prot['signature_algorithm'] = bad_algo
# recompute the signature
si_obj['signature'] = signer.sign_raw(attrs.untag().dump(), 'md5')
sig_contents = cms_writer.send(cms_obj)
# we requested in-place output
assert output is input_buf
r = PdfFileReader(input_buf)
emb = r.embedded_signatures[0]
with pytest.raises(WeakHashAlgorithmError):
await async_val_trusted(emb)
lenient_vc = ValidationContext(
trust_roots=[ROOT_CERT], weak_hash_algos=set()
)
await async_val_trusted(emb, vc=lenient_vc)
def _tamper_with_signed_attrs(attr_name, *, duplicate=False, delete=False,
replace_with=None, resign=False):
input_buf = BytesIO(MINIMAL)
w = IncrementalPdfFileWriter(input_buf)
md_algorithm = 'sha256'
cms_writer = cms_embedder.PdfCMSEmbedder().write_cms(
field_name='Signature', writer=w
)
next(cms_writer)
sig_obj = signers.SignatureObject(bytes_reserved=8192)
cms_writer.send(cms_embedder.SigObjSetup(sig_placeholder=sig_obj))
prep_digest, output = cms_writer.send(
cms_embedder.SigIOSetup(md_algorithm=md_algorithm, in_place=True)
)
signer: signers.SimpleSigner = signers.SimpleSigner(
signing_cert=FROM_CA.signing_cert, signing_key=FROM_CA.signing_key,
cert_registry=FROM_CA.cert_registry,
signature_mechanism=SignedDigestAlgorithm({
'algorithm': 'rsassa_pkcs1v15'
})
)
with pytest.deprecated_call():
# noinspection PyDeprecation
cms_obj = signer.sign(
data_digest=prep_digest.document_digest,
digest_algorithm=md_algorithm,
)
sd = cms_obj['content']
si, = sd['signer_infos']
signed_attrs = si['signed_attrs']
ix = next(
ix for ix, attr in enumerate(signed_attrs)
if attr['type'].native == attr_name
)
# mess with the attribute in the requested way
if delete:
del signed_attrs[ix]
elif duplicate:
vals = signed_attrs[ix]['values']
vals.append(vals[0])
else:
vals = signed_attrs[ix]['values']
vals[0] = replace_with
# ... and replace the signature if requested
if resign:
si['signature'] = \
signer.sign_raw(si['signed_attrs'].untag().dump(), md_algorithm)
cms_writer.send(cms_obj)
return output
def get_ac_aware_signer(actual_signer='signer1'):
pki_arch = CERTOMANCER.get_pki_arch(ArchLabel('testing-ca-with-aa'))
signer = signers.SimpleSigner(
signing_cert=pki_arch.get_cert(CertLabel(actual_signer)),
signing_key=pki_arch.key_set.get_private_key(KeyLabel(actual_signer)),
cert_registry=SimpleCertificateStore.from_certs(
[
pki_arch.get_cert('root'), pki_arch.get_cert('interm'),
pki_arch.get_cert('root-aa'), pki_arch.get_cert('interm-aa'),
pki_arch.get_cert('leaf-aa')
]
),
attribute_certs=[
pki_arch.get_attr_cert(CertLabel('alice-role-with-rev'))
]
)
return signer
async def test_no_embed_root():
w = IncrementalPdfFileWriter(BytesIO(MINIMAL))
cr = SimpleCertificateStore()
cr.register_multiple(FROM_CA.cert_registry)
no_embed_root_signer = signers.SimpleSigner(
signing_cert=FROM_CA.signing_cert, signing_key=FROM_CA.signing_key,
cert_registry=cr, embed_roots=False
)
out = await signers.async_sign_pdf(
w, signers.PdfSignatureMetadata(field_name='Sig1'),
signer=no_embed_root_signer
)
r = PdfFileReader(out)
s = r.embedded_signatures[0]
assert s.field_name == 'Sig1'
assert '/AP' not in s.sig_field
assert len(s.signed_data['certificates']) == 2
await async_val_trusted(s)
async def test_no_certificates(delete):
input_buf = BytesIO(MINIMAL)
w = IncrementalPdfFileWriter(input_buf)
md_algorithm = 'sha256'
cms_writer = cms_embedder.PdfCMSEmbedder().write_cms(
field_name='Signature', writer=w
)
next(cms_writer)
sig_obj = signers.SignatureObject(bytes_reserved=8192)
cms_writer.send(cms_embedder.SigObjSetup(sig_placeholder=sig_obj))
prep_digest, output = cms_writer.send(
cms_embedder.SigIOSetup(md_algorithm=md_algorithm, in_place=True)
)
signer: signers.SimpleSigner = signers.SimpleSigner(
signing_cert=FROM_CA.signing_cert, signing_key=FROM_CA.signing_key,
cert_registry=FROM_CA.cert_registry,
signature_mechanism=SignedDigestAlgorithm({
'algorithm': 'rsassa_pkcs1v15'
})
)
cms_obj = await signer.async_sign(
data_digest=prep_digest.document_digest,
digest_algorithm=md_algorithm,
)
sd = cms_obj['content']
if delete:
del sd['certificates']
else:
sd['certificates'] = cms.CertificateSet([])
cms_writer.send(cms_obj)
r = PdfFileReader(output)
with pytest.raises(CMSExtractionError, match='signer cert.*includ'):
emb = r.embedded_signatures[0]
await collect_validation_info(
embedded_sig=emb, validation_context=ValidationContext()
)
with pytest.raises(SignatureValidationError,
match='signer cert.*includ'):
r.embedded_signatures[0].signer_cert.dump()
def test_sign_with_explicit_dsa_implied_hash():
signer = signers.SimpleSigner(
signing_cert=TESTING_CA_DSA.get_cert(CertLabel('signer1')),
signing_key=TESTING_CA_DSA.key_set.get_private_key(
KeyLabel('signer1')),
cert_registry=SimpleCertificateStore.from_certs(
[DSA_ROOT_CERT, DSA_INTERM_CERT]),
# this is not allowed, but the validator should accept it anyway
signature_mechanism=SignedDigestAlgorithm({'algorithm': 'dsa'}))
w = IncrementalPdfFileWriter(BytesIO(MINIMAL))
out = signers.sign_pdf(w,
signers.PdfSignatureMetadata(field_name='Sig1'),
signer=signer)
r = PdfFileReader(out)
s = r.embedded_signatures[0]
si = s.signer_info
assert si['signature_algorithm']['algorithm'].native == 'dsa'
assert s.field_name == 'Sig1'
val_trusted(s, vc=SIMPLE_DSA_V_CONTEXT())
SELF_SIGN = signers.SimpleSigner.load(CRYPTO_DATA_DIR + '/selfsigned.key.pem',
CRYPTO_DATA_DIR + '/selfsigned.cert.pem',
key_passphrase=b'secret')
ROOT_CERT = TESTING_CA.get_cert(CertLabel('root'))
ECC_ROOT_CERT = TESTING_CA_ECDSA.get_cert(CertLabel('root'))
DSA_ROOT_CERT = TESTING_CA_DSA.get_cert(CertLabel('root'))
INTERM_CERT = TESTING_CA.get_cert(CertLabel('interm'))
ECC_INTERM_CERT = TESTING_CA_ECDSA.get_cert(CertLabel('interm'))
DSA_INTERM_CERT = TESTING_CA_DSA.get_cert(CertLabel('interm'))
OCSP_CERT = TESTING_CA.get_cert(CertLabel('interm-ocsp'))
REVOKED_CERT = TESTING_CA.get_cert(CertLabel('signer2'))
TSA_CERT = TESTING_CA.get_cert(CertLabel('tsa'))
TSA2_CERT = TESTING_CA.get_cert(CertLabel('tsa2'))
FROM_CA = signers.SimpleSigner(
signing_cert=TESTING_CA.get_cert(CertLabel('signer1')),
signing_key=TESTING_CA.key_set.get_private_key(KeyLabel('signer1')),
cert_registry=SimpleCertificateStore.from_certs([ROOT_CERT, INTERM_CERT]))
FROM_ECC_CA = signers.SimpleSigner(
signing_cert=TESTING_CA_ECDSA.get_cert(CertLabel('signer1')),
signing_key=TESTING_CA_ECDSA.key_set.get_private_key(KeyLabel('signer1')),
cert_registry=SimpleCertificateStore.from_certs(
[ECC_ROOT_CERT, ECC_INTERM_CERT]))
FROM_DSA_CA = signers.SimpleSigner(
signing_cert=TESTING_CA_DSA.get_cert(CertLabel('signer1')),
signing_key=TESTING_CA_DSA.key_set.get_private_key(KeyLabel('signer1')),
cert_registry=SimpleCertificateStore.from_certs(
[DSA_ROOT_CERT, DSA_INTERM_CERT]))
REVOKED_SIGNER = signers.SimpleSigner(
signing_cert=TESTING_CA.get_cert(CertLabel('signer2')),
signing_key=TESTING_CA.key_set.get_private_key(KeyLabel('signer2')),
cert_registry=SimpleCertificateStore.from_certs([ROOT_CERT, INTERM_CERT]))