File CVE-2011-4108.patch of Package compat-openssl098.703

Index: openssl-0.9.8j/ssl/d1_pkt.c
===================================================================
--- openssl-0.9.8j.orig/ssl/d1_pkt.c
+++ openssl-0.9.8j/ssl/d1_pkt.c
@@ -335,6 +335,7 @@ dtls1_process_record(SSL *s)
     SSL3_RECORD *rr;
 	unsigned int mac_size;
 	unsigned char md[EVP_MAX_MD_SIZE];
+	int decryption_failed_or_bad_record_mac = 0;
 
 
 	rr= &(s->s3->rrec);
@@ -369,12 +370,10 @@ dtls1_process_record(SSL *s)
 	enc_err = s->method->ssl3_enc->enc(s,0);
 	if (enc_err <= 0)
 		{
-		if (enc_err == 0)
-			/* SSLerr() and ssl3_send_alert() have been called */
-			goto err;
-
-		/* otherwise enc_err == -1 */
-		goto decryption_failed_or_bad_record_mac;
+		/* To minimize information leaked via timing, we will always
+		 * perform all computations before discarding the message.
+		 */
+		decryption_failed_or_bad_record_mac = 1;
 		}
 
 #ifdef TLS_DEBUG
@@ -400,7 +399,7 @@ if (	(sess == NULL) ||
 			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
 			goto f_err;
 #else
-			goto decryption_failed_or_bad_record_mac;
+			decryption_failed_or_bad_record_mac = 1;
 #endif			
 			}
 		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
@@ -411,17 +410,26 @@ if (	(sess == NULL) ||
 			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
 			goto f_err;
 #else
-			goto decryption_failed_or_bad_record_mac;
+			decryption_failed_or_bad_record_mac = 1;
 #endif
 			}
 		rr->length-=mac_size;
 		i=s->method->ssl3_enc->mac(s,md,0);
 		if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
 			{
-			goto decryption_failed_or_bad_record_mac;
+			decryption_failed_or_bad_record_mac = 1;
 			}
 		}
 
+	if (decryption_failed_or_bad_record_mac)
+		{
+		/* decryption failed, silently discard message */
+		rr->length = 0;
+		s->packet_length = 0;
+		goto err;
+		}
+
+
 	/* r->length is now just compressed */
 	if (s->expand != NULL)
 		{