commit ba932a1200b8b8507b01dd70f3c94e1ada9f63ff Author: Damian Johnson <atagar@torproject.org> Date: Wed Mar 29 19:00:10 2017 +0200 Check signing key length Ed25519 signing keys are documented as being 32 bytes. Might as well check for this. --- stem/descriptor/certificate.py | 3 +++ test/unit/descriptor/certificate.py | 8 ++++++-- test/unit/descriptor/server_descriptor.py | 1 + 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/stem/descriptor/certificate.py b/stem/descriptor/certificate.py index e29a079..bab0a44 100644 --- a/stem/descriptor/certificate.py +++ b/stem/descriptor/certificate.py @@ -172,6 +172,9 @@ class Ed25519CertificateV1(Ed25519Certificate): if remaining_flags: flags.append(ExtensionFlag.UNKNOWN) + if extension_type == ExtensionType.HAS_SIGNING_KEY and len(extension_data) != 32: + raise ValueError('Ed25519 HAS_SIGNING_KEY extension must be 32 bytes, but was %i.' % len(extension_data)) + self.extensions.append(Ed25519Extension(extension_type, flags, extension_flags, extension_data)) remaining_data = remaining_data[4 + extension_length:] diff --git a/test/unit/descriptor/certificate.py b/test/unit/descriptor/certificate.py index 57f6643..f46965a 100644 --- a/test/unit/descriptor/certificate.py +++ b/test/unit/descriptor/certificate.py @@ -41,7 +41,8 @@ class TestEd25519Certificate(unittest.TestCase): self.assertRaisesRegexp(ValueError, re.escape(exc_msg), Ed25519Certificate.parse, parse_arg) def test_basic_parsing(self): - cert_bytes = certificate(extension_data = [b'\x00\x02\x04\x07\x15\x12', b'\x00\x00\x05\x04']) + signing_key = b'\x11' * 32 + cert_bytes = certificate(extension_data = [b'\x00\x20\x04\x07' + signing_key, b'\x00\x00\x05\x04']) cert = Ed25519Certificate.parse(cert_bytes) self.assertEqual(Ed25519CertificateV1, type(cert)) @@ -54,7 +55,7 @@ class TestEd25519Certificate(unittest.TestCase): self.assertEqual(b'\x01' * ED25519_SIGNATURE_LENGTH, cert.signature) self.assertEqual([ - Ed25519Extension(type = 4, flags = [ExtensionFlag.AFFECTS_VALIDATION, ExtensionFlag.UNKNOWN], flag_int = 7, data = b'\x15\x12'), + Ed25519Extension(type = ExtensionType.HAS_SIGNING_KEY, flags = [ExtensionFlag.AFFECTS_VALIDATION, ExtensionFlag.UNKNOWN], flag_int = 7, data = signing_key), Ed25519Extension(type = 5, flags = [ExtensionFlag.UNKNOWN], flag_int = 4, data = b''), ], cert.extensions) @@ -92,6 +93,9 @@ class TestEd25519Certificate(unittest.TestCase): self.assert_raises(certificate(extension_data = [b'']), 'Ed25519 extension is missing header field data') self.assert_raises(certificate(extension_data = [b'\x50\x00\x00\x00\x15\x12']), "Ed25519 extension is truncated. It should have 20480 bytes of data but there's only 2.") + def test_truncated_signing_key(self): + self.assert_raises(certificate(extension_data = [b'\x00\x02\x04\x07\11\12']), "Ed25519 HAS_SIGNING_KEY extension must be 32 bytes, but was 2.") + def test_extra_extension_data(self): self.assert_raises(certificate(extension_data = [b'\x00\x01\x00\x00\x15\x12']), "Ed25519 certificate had 1 bytes of unused extension data") diff --git a/test/unit/descriptor/server_descriptor.py b/test/unit/descriptor/server_descriptor.py index 5a1d94f..8af55c6 100644 --- a/test/unit/descriptor/server_descriptor.py +++ b/test/unit/descriptor/server_descriptor.py @@ -9,6 +9,7 @@ import tarfile import time import unittest +import stem.descriptor import stem.descriptor.server_descriptor import stem.exit_policy import stem.prereq