Commit 83cb7c46 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

An incompatibility has always existed between the format used for RSA 

signatures and MDC2 using EVP or RSA_sign. This has become more apparent
when the dgst utility in OpenSSL 1.0.0 and later switched to using the
EVP_DigestSign functions which call RSA_sign.

This means that the signature format OpenSSL 1.0.0 and later used with
dgst -sign and MDC2 is incompatible with previous versions.

Add detection in RSA_verify so either format works.

Note: MDC2 is disabled by default in OpenSSL and very rarely used in practice.
parent 04296664

CHANGES

+7 −0
Original line number Diff line number Diff line
@@ -267,6 +267,13 @@ 
  

 Changes between 1.0.0f and 1.0.1  [xx XXX xxxx]



  *) The format used for MDC2 RSA signatures is inconsistent between EVP

     and the RSA_sign/RSA_verify functions. This was made more apparent when

     OpenSSL used RSA_sign/RSA_verify for some RSA signatures in particular

     those which went through EVP_PKEY_METHOD in 1.0.0 and later. Detect 

     the correct format in RSA_verify so both forms transparently work.

     [Steve Henson]



  *) Some servers which support TLS 1.0 can choke if we initially indicate

     support for TLS 1.2 and later renegotiate using TLS 1.0 in the RSA

     encrypted premaster secret. As a workaround use the maximum pemitted

crypto/rsa/rsa_sign.c

+16 −0
Original line number Diff line number Diff line
@@ -182,6 +182,22 @@ int int_rsa_verify(int dtype, const unsigned char *m, 
	i=RSA_public_decrypt((int)siglen,sigbuf,s,rsa,RSA_PKCS1_PADDING);



	if (i <= 0) goto err;

	/* Oddball MDC2 case: signature can be OCTET STRING.

	 * check for correct tag and length octets.

	 */

	if (dtype == NID_mdc2 && i == 18 && s[0] == 0x04 && s[1] == 0x10)

		{

		if (rm)

			{

			memcpy(rm, s + 2, 16);

			*prm_len = 16;

			ret = 1;

			}

		else if(memcmp(m, s + 2, 16))

			RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);

		else

			ret = 1;

		}



	/* Special case: SSL signature */

	if(dtype == NID_md5_sha1) {