commit b47368a00a84649051b8778b0838dfa76148c6b8
author Manuel Pégourié-Gonnard <mpg@elzevir.fr> Wed Sep 24 13:29:58 2014 +0200
committer Paul Bakker <p.j.bakker@polarssl.org> Tue Oct 21 16:32:34 2014 +0200
tree 79de66fe5041a392d948ae87bfe302e9c81b3a06
parent 4956fd74372f85d7339601347f1ade78f6ee06fd

Add replay detection

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index d48ccf5..76a7515 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2104,6 +2104,10 @@
     }
 }
 
+#if defined(POLARSSL_SSL_DTLS_ANTI_REPLAY)
+static void ssl_dtls_replay_reset( ssl_context *ssl );
+#endif
+
 /*
  * Swap transform_out and out_ctr with the alternative ones
  */
@@ -2830,7 +2834,7 @@
         return( POLARSSL_ERR_SSL_INVALID_RECORD );
     }
 
-    /* Check epoch with DTLS */
+    /* Check epoch (and sequence number) with DTLS */
 #if defined(POLARSSL_SSL_PROTO_DTLS)
     if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
     {
@@ -2839,13 +2843,21 @@
 
         if( exp_epoch != rec_epoch )
         {
-            SSL_DEBUG_MSG( 1, ( "discarding record from another epoch: "
+            SSL_DEBUG_MSG( 1, ( "record from another epoch: "
                                 "expected %d, received %d",
                                  exp_epoch,   rec_epoch ) );
-            return( POLARSSL_ERR_NET_WANT_READ );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
         }
-    }
+
+#if defined(POLARSSL_SSL_DTLS_ANTI_REPLAY)
+        if( ssl_dtls_replay_check( ssl ) != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "replayed record" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
 #endif
+    }
+#endif /* POLARSSL_SSL_PROTO_DTLS */
 
     /* Check length against the size of our buffer */
     if( ssl->in_msglen > SSL_BUFFER_LEN
@@ -2959,6 +2971,14 @@
     }
 #endif /* POLARSSL_ZLIB_SUPPORT */
 
+#if defined(POLARSSL_SSL_PROTO_DTLS) && \
+    defined(POLARSSL_SSL_DTLS_ANTI_REPLAY)
+    if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
+    {
+        ssl_dtls_replay_update( ssl );
+    }
+#endif
+
     return( 0 );
 }
 
@@ -4197,8 +4217,9 @@
     {
         unsigned char i;
 
-        /* Set sequence_number to zero */
-        memset( ssl->in_ctr + 2, 0, 6 );
+#if defined(POLARSSL_SSL_DTLS_ANTI_REPLAY)
+        ssl_dtls_replay_reset( ssl );
+#endif
 
         /* Increment epoch */
         for( i = 2; i > 0; i-- )
@@ -4547,6 +4568,9 @@
 #if defined(POLARSSL_SSL_PROTO_DTLS)
     ssl->next_record_offset = 0;
 #endif
+#if defined(POLARSSL_SSL_DTLS_ANTI_REPLAY)
+    ssl_dtls_replay_reset( ssl );
+#endif
 
     ssl->in_hslen = 0;
     ssl->nb_zero = 0;