Disable encrypt them mac for SSL 3.0 and stream ciphers (RC4 only).
authorDr. Stephen Henson <steve@openssl.org>
Tue, 30 Sep 2014 21:10:29 +0000 (22:10 +0100)
committerDr. Stephen Henson <steve@openssl.org>
Fri, 10 Oct 2014 12:23:29 +0000 (13:23 +0100)
Reviewed-by: Tim Hudson <tjh@openssl.org>
ssl/t1_lib.c

index dc108aa..d0602fb 100644 (file)
@@ -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
-       s2n(TLSEXT_TYPE_encrypt_then_mac,ret);
-       s2n(0,ret);
+       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)
-                       s->s3->flags |= TLS1_FLAGS_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