releasetools: Use delta_generator to verify payload signatures.
We used to take a hard approach by parsing the payload with Python
script. This can be done by calling deleta_generator directly, which
also avoids the dependency on protobuf.
- Passing case
$ ./build/make/tools/releasetools/check_ota_package_signature.py \
build/target/product/security/testkey.x509.pem \
out/dist/aosp_marlin-ota-eng.zip
Package: out/dist/aosp_marlin-ota-eng.zip
Certificate: build/target/product/security/testkey.x509.pem
...
Whole package signature VERIFIED
Verifying A/B OTA payload signatures...
[1215/122842:INFO:generate_delta_main.cc(171)] Verifying signed payload.
[1215/122845:INFO:payload_verifier.cc(93)] signature blob size = 264
[1215/122845:INFO:payload_verifier.cc(112)] Verified correct signature 1 out of 1 signatures.
[1215/122845:INFO:payload_verifier.cc(93)] signature blob size = 264
[1215/122845:INFO:payload_verifier.cc(112)] Verified correct signature 1 out of 1 signatures.
[1215/122845:INFO:generate_delta_main.cc(181)] Done verifying signed payload.
Payload signatures VERIFIED
$ echo $?
0
- Failing case
Sign the whole package file with a different key, but leaving payload entries intact.
$ ./build/make/tools/releasetools/check_ota_package_signature.py \
testkey2.x509.pem \
marlin-ota-mismatching.zip
Package: marlin-ota-mismatching.zip
Certificate: testkey2.x509.pem
...
Whole package signature VERIFIED
Verifying A/B OTA payload signatures...
[1215/123054:INFO:generate_delta_main.cc(171)] Verifying signed payload.
[1215/123056:INFO:payload_verifier.cc(93)] signature blob size = 264
[1215/123056:ERROR:payload_verifier.cc(118)] None of the 1 signatures is correct. Expected:
[1215/123056:INFO:utils.cc(444)] Logging array of length: 256
[1215/123056:INFO:utils.cc(461)] 0x00000000 : 00 01 ff ff ff ff ff ff ff ff ff ff ff ff ff ff
...
[1215/123056:ERROR:payload_verifier.cc(121)] But found decrypted hashes:
[1215/123056:INFO:utils.cc(444)] Logging array of length: 256
[1215/123056:INFO:utils.cc(461)] 0x00000000 : 52 68 78 36 f6 9e cd 2d 5e 9f 31 d5 26 03 c9 aa
...
[1215/123056:ERROR:payload_signer.cc(333)] PayloadVerifier::VerifySignature( signature_blob, public_key_path, payload_hash) failed.
[1215/123056:INFO:generate_delta_main.cc(177)] VerifySignedPayload failed
ERROR: Failed to verify payload with delta_generator: marlin-ota-mismatching.zip
$ echo $?
1
Bug: 65261072
Test: See above.
Change-Id: Id2e065655ec49b80dd2b13c6a859f41913be055b
diff --git a/tools/releasetools/check_ota_package_signature.py b/tools/releasetools/check_ota_package_signature.py
index 8106d06..b5e9d8b 100755
--- a/tools/releasetools/check_ota_package_signature.py
+++ b/tools/releasetools/check_ota_package_signature.py
@@ -21,11 +21,7 @@
from __future__ import print_function
import argparse
-import common
-import os
-import os.path
import re
-import site
import subprocess
import sys
import tempfile
@@ -34,15 +30,7 @@
from hashlib import sha1
from hashlib import sha256
-# 'update_payload' package is under 'system/update_engine/scripts/', which
-# should be included in PYTHONPATH. Try to set it up automatically if
-# if ANDROID_BUILD_TOP is available.
-top = os.getenv('ANDROID_BUILD_TOP')
-if top:
- site.addsitedir(os.path.join(top, 'system', 'update_engine', 'scripts'))
-
-from update_payload.payload import Payload
-from update_payload.update_metadata_pb2 import Signatures
+import common
def CertUsesSha256(cert):
@@ -108,10 +96,7 @@
use_sha256 = CertUsesSha256(cert)
print('Use SHA-256: %s' % (use_sha256,))
- if use_sha256:
- h = sha256()
- else:
- h = sha1()
+ h = sha256() if use_sha256 else sha1()
h.update(package_bytes[:signed_len])
package_digest = h.hexdigest().lower()
@@ -161,40 +146,6 @@
def VerifyAbOtaPayload(cert, package):
"""Verifies the payload and metadata signatures in an A/B OTA payload."""
-
- def VerifySignatureBlob(hash_file, blob):
- """Verifies the input hash_file against the signature blob."""
- signatures = Signatures()
- signatures.ParseFromString(blob)
-
- extracted_sig_file = common.MakeTempFile(
- prefix='extracted-sig-', suffix='.bin')
- # In Android, we only expect one signature.
- assert len(signatures.signatures) == 1, \
- 'Invalid number of signatures: %d' % len(signatures.signatures)
- signature = signatures.signatures[0]
- length = len(signature.data)
- assert length == 256, 'Invalid signature length %d' % (length,)
- with open(extracted_sig_file, 'w') as f:
- f.write(signature.data)
-
- # Verify the signature file extracted from the payload, by reversing the
- # signing operation. Alternatively, this can be done by calling 'openssl
- # rsautl -verify -certin -inkey <cert.pem> -in <extracted_sig_file> -out
- # <output>', then to assert that
- # <output> == SHA-256 DigestInfo prefix || <hash_file>.
- cmd = ['openssl', 'pkeyutl', '-verify', '-certin', '-inkey', cert,
- '-pkeyopt', 'digest:sha256', '-in', hash_file,
- '-sigfile', extracted_sig_file]
- p = common.Run(cmd, stdout=subprocess.PIPE)
- result, _ = p.communicate()
-
- # https://github.com/openssl/openssl/pull/3213
- # 'openssl pkeyutl -verify' (prior to 1.1.0) returns non-zero return code,
- # even on successful verification. To avoid the false alarm with older
- # openssl, check the output directly.
- assert result.strip() == 'Signature Verified Successfully', result.strip()
-
package_zip = zipfile.ZipFile(package, 'r')
if 'payload.bin' not in package_zip.namelist():
common.ZipClose(package_zip)
@@ -202,37 +153,27 @@
print('Verifying A/B OTA payload signatures...')
+ # Dump pubkey from the certificate.
+ pubkey = common.MakeTempFile(prefix="key-", suffix=".key")
+ cmd = ['openssl', 'x509', '-pubkey', '-noout', '-in', cert, '-out', pubkey]
+ proc = common.Run(cmd, stdout=subprocess.PIPE)
+ stdoutdata, _ = proc.communicate()
+ assert proc.returncode == 0, \
+ 'Failed to dump public key from certificate: %s\n%s' % (cert, stdoutdata)
+
package_dir = tempfile.mkdtemp(prefix='package-')
common.OPTIONS.tempfiles.append(package_dir)
+ # Signature verification with delta_generator.
payload_file = package_zip.extract('payload.bin', package_dir)
- payload = Payload(open(payload_file, 'rb'))
- payload.Init()
-
- # Extract the payload hash and metadata hash from the payload.bin.
- payload_hash_file = common.MakeTempFile(prefix='hash-', suffix='.bin')
- metadata_hash_file = common.MakeTempFile(prefix='hash-', suffix='.bin')
- cmd = ['brillo_update_payload', 'hash',
- '--unsigned_payload', payload_file,
- '--signature_size', '256',
- '--metadata_hash_file', metadata_hash_file,
- '--payload_hash_file', payload_hash_file]
- p = common.Run(cmd, stdout=subprocess.PIPE)
- p.communicate()
- assert p.returncode == 0, 'brillo_update_payload hash failed'
-
- # Payload signature verification.
- assert payload.manifest.HasField('signatures_offset')
- payload_signature = payload.ReadDataBlob(
- payload.manifest.signatures_offset, payload.manifest.signatures_size)
- VerifySignatureBlob(payload_hash_file, payload_signature)
-
- # Metadata signature verification.
- metadata_signature = payload.ReadDataBlob(
- -payload.header.metadata_signature_len,
- payload.header.metadata_signature_len)
- VerifySignatureBlob(metadata_hash_file, metadata_signature)
-
+ cmd = ['delta_generator',
+ '--in_file=' + payload_file,
+ '--public_key=' + pubkey]
+ proc = common.Run(cmd, stdout=subprocess.PIPE)
+ stdoutdata, _ = proc.communicate()
+ assert proc.returncode == 0, \
+ 'Failed to verify payload with delta_generator: %s\n%s' % (package,
+ stdoutdata)
common.ZipClose(package_zip)
# Verified successfully upon reaching here.