commit 60ca5afaecadbe8eeb0d3f66e21a8029ea5d56f1
author Manuel Pégourié-Gonnard <mpg@elzevir.fr> Wed Sep 03 16:02:42 2014 +0200
committer Paul Bakker <p.j.bakker@polarssl.org> Tue Oct 21 16:30:25 2014 +0200
tree 4db4d227ad34e307779a894d196072dc988dd4d9
parent 0a65934ef3e95ea374000587a9e48291b065c005

Drop records from wrong epoch

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 263e64e..71d07b5 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2469,6 +2469,13 @@
         return( ret );
     }
 
+    /*
+     * ContentType type;
+     * ProtocolVersion version;
+     * uint16 epoch;            // DTLS only
+     * uint48 sequence_number;  // DTLS only
+     * uint16 length;
+     */
     SSL_DEBUG_BUF( 4, "input record header", ssl->in_hdr, ssl_hdr_len( ssl ) );
 
     ssl->in_msgtype =  ssl->in_hdr[0];
@@ -2511,6 +2518,23 @@
         return( POLARSSL_ERR_SSL_INVALID_RECORD );
     }
 
+    /* Check epoch with DTLS */
+#if defined(POLARSSL_SSL_PROTO_DTLS)
+    if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
+    {
+        unsigned int exp_epoch = ( ssl->in_ctr[0] << 8 ) | ssl->in_ctr[1];
+        unsigned int rec_epoch = ( ssl->in_hdr[3] << 8 ) | ssl->in_hdr[4];
+
+        if( exp_epoch != rec_epoch )
+        {
+            SSL_DEBUG_MSG( 1, ( "discarding record from another epoch: "
+                                "expected %d, received %d",
+                                 exp_epoch,   rec_epoch ) );
+            return( POLARSSL_ERR_NET_WANT_READ );
+        }
+    }
+#endif
+
     /* Check length against the size of our buffer */
     if( ssl->in_msglen > SSL_BUFFER_LEN
                          - (size_t)( ssl->in_msg - ssl->in_buf ) )