diff --git a/library/ssl_tls.c b/library/ssl_tls.c index 263e64ec9..71d07b5a9 100644 --- a/library/ssl_tls.c +++ b/library/ssl_tls.c @@ -2469,6 +2469,13 @@ int ssl_read_record( ssl_context *ssl ) 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 @@ int ssl_read_record( ssl_context *ssl ) 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 ) )