Merge "Allow system partition to be absent"
diff --git a/avbtool b/avbtool
index b027bbd..f22f439 100755
--- a/avbtool
+++ b/avbtool
@@ -544,13 +544,52 @@
modulus = decode_long(modulus_blob)
exponent = 65537
- # For now, just use Crypto.PublicKey.RSA to verify the signature. This
- # is OK since 'avbtool verify_image' is not expected to run on the
- # Android builders (see bug #36809096).
- import Crypto.PublicKey.RSA
- key = Crypto.PublicKey.RSA.construct((modulus, long(exponent)))
- if not key.verify(decode_long(padding_and_digest),
- (decode_long(sig_blob), None)):
+ # We used to have this:
+ #
+ # import Crypto.PublicKey.RSA
+ # key = Crypto.PublicKey.RSA.construct((modulus, long(exponent)))
+ # if not key.verify(decode_long(padding_and_digest),
+ # (decode_long(sig_blob), None)):
+ # return False
+ # return True
+ #
+ # but since 'avbtool verify_image' is used on the builders we don't want
+ # to rely on Crypto.PublicKey.RSA. Instead just use openssl(1) to verify.
+ asn1_str = ('asn1=SEQUENCE:pubkeyinfo\n'
+ '\n'
+ '[pubkeyinfo]\n'
+ 'algorithm=SEQUENCE:rsa_alg\n'
+ 'pubkey=BITWRAP,SEQUENCE:rsapubkey\n'
+ '\n'
+ '[rsa_alg]\n'
+ 'algorithm=OID:rsaEncryption\n'
+ 'parameter=NULL\n'
+ '\n'
+ '[rsapubkey]\n'
+ 'n=INTEGER:%s\n'
+ 'e=INTEGER:%s\n' % (hex(modulus).rstrip('L'), hex(exponent).rstrip('L')))
+ asn1_tmpfile = tempfile.NamedTemporaryFile()
+ asn1_tmpfile.write(asn1_str)
+ asn1_tmpfile.flush()
+ der_tmpfile = tempfile.NamedTemporaryFile()
+ p = subprocess.Popen(
+ ['openssl', 'asn1parse', '-genconf', asn1_tmpfile.name, '-out', der_tmpfile.name, '-noout'])
+ retcode = p.wait()
+ if retcode != 0:
+ raise AvbError('Error generating DER file')
+
+ p = subprocess.Popen(
+ ['openssl', 'rsautl', '-verify', '-pubin', '-inkey', der_tmpfile.name, '-keyform', 'DER', '-raw'],
+ stdin=subprocess.PIPE,
+ stdout=subprocess.PIPE,
+ stderr=subprocess.PIPE)
+ (pout, perr) = p.communicate(str(sig_blob))
+ retcode = p.wait()
+ if retcode != 0:
+ raise AvbError('Error verifying data: {}'.format(perr))
+ recovered_data = bytearray(pout)
+ if recovered_data != padding_and_digest:
+ sys.stderr.write('Signature not correct\n')
return False
return True
