PR: 2229

Submitted By: Robin Seggelmann <seggelmann@fh-muenster.de>

Don't drop DTLS connection if mac or decryption failed.

ssl/d1_pkt.c

@@ -417,7 +417,7 @@ dtls1_process_record(SSL *s)
 			goto err;
 
 		/* otherwise enc_err == -1 */
-		goto decryption_failed_or_bad_record_mac;
+		goto err;
 		}
 
 #ifdef TLS_DEBUG
@@ -447,7 +447,7 @@ printf("\n");
 			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
 			goto f_err;
 #else
-			goto decryption_failed_or_bad_record_mac;
+			goto err;
 #endif			
 			}
 		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
@@ -458,14 +458,14 @@ printf("\n");
 			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
 			goto f_err;
 #else
-			goto decryption_failed_or_bad_record_mac;
+			goto err;
 #endif
 			}
 		rr->length-=mac_size;
 		i=s->method->ssl3_enc->mac(s,md,0);
 		if (i < 0 || memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
 			{
-			goto decryption_failed_or_bad_record_mac;
+			goto err;
 			}
 		}
 
@@ -507,14 +507,6 @@ printf("\n");
 	dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
 	return(1);
 
-decryption_failed_or_bad_record_mac:
-	/* Separate 'decryption_failed' alert was introduced with TLS 1.0,
-	 * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
-	 * failure is directly visible from the ciphertext anyway,
-	 * we should not reveal which kind of error occured -- this
-	 * might become visible to an attacker (e.g. via logfile) */
-	al=SSL_AD_BAD_RECORD_MAC;
-	SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
 f_err:
 	ssl3_send_alert(s,SSL3_AL_FATAL,al);
 err:
@@ -547,8 +539,7 @@ int dtls1_get_record(SSL *s)
 
 	/* The epoch may have changed.  If so, process all the
 	 * pending records.  This is a non-blocking operation. */
-	if ( ! dtls1_process_buffered_records(s))
-            return 0;
+	dtls1_process_buffered_records(s);
 
 	/* if we're renegotiating, then there may be buffered records */
 	if (dtls1_get_processed_record(s))
@@ -683,8 +674,12 @@ again:
 		goto again;
 		}
 
-	if ( ! dtls1_process_record(s))
-		return(0);
+	if (!dtls1_process_record(s))
+		{
+		rr->length = 0;
+		s->packet_length = 0;  /* dump this record */
+		goto again;   /* get another record */
+		}
 
 	dtls1_clear_timeouts(s);  /* done waiting */
 	return(1);