diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py index 1e7bb3a948..dfcfb49378 100755 --- a/tools/releasetools/ota_from_target_files.py +++ b/tools/releasetools/ota_from_target_files.py @@ -171,8 +171,16 @@ A/B OTA specific options --payload_signer_args Specify the arguments needed for payload signer. + --payload_signer_maximum_signature_size + The maximum signature size (in bytes) that would be generated by the given + payload signer. Only meaningful when custom payload signer is specified + via '--payload_signer'. + If the signer uses a RSA key, this should be the number of bytes to + represent the modulus. If it uses an EC key, this is the size of a + DER-encoded ECDSA signature. + --payload_signer_key_size - Specify the key size in bytes of the payload signer. + Deprecated. Use the '--payload_signer_maximum_signature_size' instead. --skip_postinstall Skip the postinstall hooks when generating an A/B OTA package (default: @@ -231,7 +239,7 @@ OPTIONS.stash_threshold = 0.8 OPTIONS.log_diff = None OPTIONS.payload_signer = None OPTIONS.payload_signer_args = [] -OPTIONS.payload_signer_key_size = None +OPTIONS.payload_signer_maximum_signature_size = None OPTIONS.extracted_input = None OPTIONS.key_passwords = [] OPTIONS.skip_postinstall = False @@ -288,35 +296,31 @@ class PayloadSigner(object): self.signer = "openssl" self.signer_args = ["pkeyutl", "-sign", "-inkey", signing_key, "-pkeyopt", "digest:sha256"] - self.key_size = self._GetKeySizeInBytes(signing_key) + self.maximum_signature_size = self._GetMaximumSignatureSizeInBytes( + signing_key) else: self.signer = OPTIONS.payload_signer self.signer_args = OPTIONS.payload_signer_args - if OPTIONS.payload_signer_key_size: - self.key_size = int(OPTIONS.payload_signer_key_size) - assert self.key_size == 256 or self.key_size == 512, \ - "Unsupported key size {}".format(OPTIONS.payload_signer_key_size) + if OPTIONS.payload_signer_maximum_signature_size: + self.maximum_signature_size = int( + OPTIONS.payload_signer_maximum_signature_size) else: - self.key_size = 256 + # The legacy config uses RSA2048 keys. + logger.warning("The maximum signature size for payload signer is not" + " set, default to 256 bytes.") + self.maximum_signature_size = 256 @staticmethod - def _GetKeySizeInBytes(signing_key): - modulus_file = common.MakeTempFile(prefix="modulus-") - cmd = ["openssl", "rsa", "-inform", "PEM", "-in", signing_key, "-modulus", - "-noout", "-out", modulus_file] - common.RunAndCheckOutput(cmd, verbose=False) - - with open(modulus_file) as f: - modulus_string = f.read() - # The modulus string has the format "Modulus=$data", where $data is the - # concatenation of hex dump of the modulus. - MODULUS_PREFIX = "Modulus=" - assert modulus_string.startswith(MODULUS_PREFIX) - modulus_string = modulus_string[len(MODULUS_PREFIX):] - key_size = len(modulus_string) // 2 - assert key_size == 256 or key_size == 512, \ - "Unsupported key size {}".format(key_size) - return key_size + def _GetMaximumSignatureSizeInBytes(signing_key): + out_signature_size_file = common.MakeTempFile("signature_size") + cmd = ["delta_generator", "--out_maximum_signature_size_file={}".format( + out_signature_size_file), "--private_key={}".format(signing_key)] + common.RunAndCheckOutput(cmd) + with open(out_signature_size_file) as f: + signature_size = f.read().rstrip() + logger.info("% outputs the maximum signature size: %", cmd[0], + signature_size) + return int(signature_size) def Sign(self, in_file): """Signs the given input file. Returns the output filename.""" @@ -396,7 +400,7 @@ class Payload(object): metadata_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin") cmd = ["brillo_update_payload", "hash", "--unsigned_payload", self.payload_file, - "--signature_size", str(payload_signer.key_size), + "--signature_size", str(payload_signer.maximum_signature_size), "--metadata_hash_file", metadata_sig_file, "--payload_hash_file", payload_sig_file] self._Run(cmd) @@ -411,7 +415,7 @@ class Payload(object): cmd = ["brillo_update_payload", "sign", "--unsigned_payload", self.payload_file, "--payload", signed_payload_file, - "--signature_size", str(payload_signer.key_size), + "--signature_size", str(payload_signer.maximum_signature_size), "--metadata_signature_file", signed_metadata_sig_file, "--payload_signature_file", signed_payload_sig_file] self._Run(cmd) @@ -2005,8 +2009,13 @@ def main(argv): OPTIONS.payload_signer = a elif o == "--payload_signer_args": OPTIONS.payload_signer_args = shlex.split(a) + elif o == "--payload_signer_maximum_signature_size": + OPTIONS.payload_signer_maximum_signature_size = a elif o == "--payload_signer_key_size": - OPTIONS.payload_signer_key_size = a + # TODO(Xunchang) remove this option after cleaning up the callers. + logger.warning("The option '--payload_signer_key_size' is deprecated." + " Use '--payload_signer_maximum_signature_size' instead.") + OPTIONS.payload_signer_maximum_signature_size = a elif o == "--extracted_input_target_files": OPTIONS.extracted_input = a elif o == "--skip_postinstall": @@ -2047,6 +2056,7 @@ def main(argv): "log_diff=", "payload_signer=", "payload_signer_args=", + "payload_signer_maximum_signature_size=", "payload_signer_key_size=", "extracted_input_target_files=", "skip_postinstall", diff --git a/tools/releasetools/test_ota_from_target_files.py b/tools/releasetools/test_ota_from_target_files.py index c3021a16f0..38faf64aa6 100644 --- a/tools/releasetools/test_ota_from_target_files.py +++ b/tools/releasetools/test_ota_from_target_files.py @@ -885,10 +885,28 @@ class AbOtaPropertyFilesTest(PropertyFilesTest): payload_offset, metadata_total = ( property_files._GetPayloadMetadataOffsetAndSize(input_zip)) - # Read in the metadata signature directly. + # The signature proto has the following format (details in + # /platform/system/update_engine/update_metadata.proto): + # message Signature { + # optional uint32 version = 1; + # optional bytes data = 2; + # optional fixed32 unpadded_signature_size = 3; + # } + # + # According to the protobuf encoding, the tail of the signature message will + # be [signature string(256 bytes) + encoding of the fixed32 number 256]. And + # 256 is encoded as 'x1d\x00\x01\x00\x00': + # [3 (field number) << 3 | 5 (type) + byte reverse of 0x100 (256)]. + # Details in (https://developers.google.com/protocol-buffers/docs/encoding) + signature_tail_length = self.SIGNATURE_SIZE + 5 + self.assertGreater(metadata_total, signature_tail_length) with open(output_file, 'rb') as verify_fp: - verify_fp.seek(payload_offset + metadata_total - self.SIGNATURE_SIZE) - metadata_signature = verify_fp.read(self.SIGNATURE_SIZE) + verify_fp.seek(payload_offset + metadata_total - signature_tail_length) + metadata_signature_proto_tail = verify_fp.read(signature_tail_length) + + self.assertEqual(b'\x1d\x00\x01\x00\x00', + metadata_signature_proto_tail[-5:]) + metadata_signature = metadata_signature_proto_tail[:-5] # Now we extract the metadata hash via brillo_update_payload script, which # will serve as the oracle result. @@ -1050,11 +1068,13 @@ class PayloadSignerTest(test_utils.ReleaseToolsTestCase): with open(file1, 'rb') as fp1, open(file2, 'rb') as fp2: self.assertEqual(fp1.read(), fp2.read()) + @test_utils.SkipIfExternalToolsUnavailable() def test_init(self): payload_signer = PayloadSigner() self.assertEqual('openssl', payload_signer.signer) - self.assertEqual(256, payload_signer.key_size) + self.assertEqual(256, payload_signer.maximum_signature_size) + @test_utils.SkipIfExternalToolsUnavailable() def test_init_withPassword(self): common.OPTIONS.package_key = os.path.join( self.testdata_dir, 'testkey_with_passwd') @@ -1067,18 +1087,27 @@ class PayloadSignerTest(test_utils.ReleaseToolsTestCase): def test_init_withExternalSigner(self): common.OPTIONS.payload_signer = 'abc' common.OPTIONS.payload_signer_args = ['arg1', 'arg2'] - common.OPTIONS.payload_signer_key_size = '512' + common.OPTIONS.payload_signer_maximum_signature_size = '512' payload_signer = PayloadSigner() self.assertEqual('abc', payload_signer.signer) self.assertEqual(['arg1', 'arg2'], payload_signer.signer_args) - self.assertEqual(512, payload_signer.key_size) + self.assertEqual(512, payload_signer.maximum_signature_size) - def test_GetKeySizeInBytes_512Bytes(self): + @test_utils.SkipIfExternalToolsUnavailable() + def test_GetMaximumSignatureSizeInBytes_512Bytes(self): signing_key = os.path.join(self.testdata_dir, 'testkey_RSA4096.key') # pylint: disable=protected-access - key_size = PayloadSigner._GetKeySizeInBytes(signing_key) - self.assertEqual(512, key_size) + signature_size = PayloadSigner._GetMaximumSignatureSizeInBytes(signing_key) + self.assertEqual(512, signature_size) + @test_utils.SkipIfExternalToolsUnavailable() + def test_GetMaximumSignatureSizeInBytes_ECKey(self): + signing_key = os.path.join(self.testdata_dir, 'testkey_EC.key') + # pylint: disable=protected-access + signature_size = PayloadSigner._GetMaximumSignatureSizeInBytes(signing_key) + self.assertEqual(72, signature_size) + + @test_utils.SkipIfExternalToolsUnavailable() def test_Sign(self): payload_signer = PayloadSigner() input_file = os.path.join(self.testdata_dir, self.SIGFILE) diff --git a/tools/releasetools/testdata/testkey_EC.key b/tools/releasetools/testdata/testkey_EC.key new file mode 100644 index 0000000000..9e65a68a36 --- /dev/null +++ b/tools/releasetools/testdata/testkey_EC.key @@ -0,0 +1,5 @@ +-----BEGIN PRIVATE KEY----- +MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgGaguGj8Yb1KkqKHd +ISblUsjtOCbzAuVpX81i02sm8FWhRANCAARBnuotwKOsuvjH6iwTDhOAi7Q5pLWz +xDkZjg2pcfbfi9FFTvLYETas7B2W6fx9PUezUmHTFTDV2JZuMYYFdZOw +-----END PRIVATE KEY-----