Commit f3014206 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

Disable encrypt them mac for SSL 3.0 and stream ciphers (RC4 only). 



Reviewed-by: default avatarTim Hudson <tjh@openssl.org>
parent e0fdea3e

ssl/t1_lib.c

+18 −8
Original line number Diff line number Diff line
@@ -1485,8 +1485,11 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned c 
	if (!custom_ext_add(s, 0, &ret, limit, al))

		return NULL;

#ifdef TLSEXT_TYPE_encrypt_then_mac

	if (s->version != SSL3_VERSION)

		{

		s2n(TLSEXT_TYPE_encrypt_then_mac,ret);

		s2n(0,ret);

		}

#endif



	/* Add padding to workaround bugs in F5 terminators.
@@ -1719,10 +1722,12 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned c 
#ifdef TLSEXT_TYPE_encrypt_then_mac

	if (s->s3->flags & TLS1_FLAGS_ENCRYPT_THEN_MAC)

		{

		/* Don't use encrypt_then_mac if AEAD: might want

		 * to disable for other ciphersuites too.

		/* Don't use encrypt_then_mac if AEAD, RC4 or SSL 3.0:

		 * might want to disable for other cases too.

		 */

		if (s->s3->tmp.new_cipher->algorithm_mac == SSL_AEAD)

		if (s->s3->tmp.new_cipher->algorithm_mac == SSL_AEAD

		    || s->s3->tmp.new_cipher->algorithm_enc == SSL_RC4

		    || s->version == SSL3_VERSION)

			s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC;

		else

			{
@@ -2436,7 +2441,10 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char 
                        }

#ifdef TLSEXT_TYPE_encrypt_then_mac

		else if (type == TLSEXT_TYPE_encrypt_then_mac)

			{

			if (s->version != SSL3_VERSION)

				s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC;

			}

#endif

		/* If this ClientHello extension was unhandled and this is 

		 * a nonresumed connection, check whether the extension is a
@@ -2777,8 +2785,10 @@ static int ssl_scan_serverhello_tlsext(SSL *s, unsigned char **p, unsigned char 
#ifdef TLSEXT_TYPE_encrypt_then_mac

		else if (type == TLSEXT_TYPE_encrypt_then_mac)

			{

			/* Ignore if inappropriate ciphersuite */

			if (s->s3->tmp.new_cipher->algorithm_mac != SSL_AEAD)

			/* Ignore if inappropriate ciphersuite or SSL 3.0 */

			if (s->s3->tmp.new_cipher->algorithm_mac != SSL_AEAD

			    && s->s3->tmp.new_cipher->algorithm_enc != SSL_RC4

			    && s->version != SSL3_VERSION)

				s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC;

			}

#endif