[openssl.org #2228] [PATCH] DTLS MAC validation fails for buffered messages

[Robin Seggelmann via RT]

Whenever handshake messages are buffered because they arrived reordered and 
already belong to the next epoch, the MAC validation fails when the messages 
are finally processed because the sequence number is not restored and instead 0 
is always used. This is fixed with setting the s->s3->read_sequence variable 
when retrieving buffered messages.


--- ssl/d1_pkt.c        6 Apr 2010 12:44:55 -0000       1.27.2.20
+++ ssl/d1_pkt.c        8 Apr 2010 10:43:29 -0000
@@ -196,6 +196,9 @@
     s->packet_length = rdata->packet_length;
     memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
     memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
+       
+       /* Set proper sequence number for mac calculation */
+       memcpy(&(s->s3->read_sequence[2]), &(rdata->packet[5]), 6);
     
     return(1);
     }

dtls-badmac-bug-0.9.8.patch
Description: Binary data

dtls-badmac-bug-1.0.0.patch
Description: Binary data