DTLS fixes.

Corrected bugs in DTLS sliding window code to account for lost packets
arriving after an epoch change. The last handshake flight is now being
kept by both parties in order to be used as a lost packet indication.

diff --git a/lib/debug.c b/lib/debug.c
index fc350f3515213593c3df50783c6ec93de277881a..1e5b0c6fb83b60ed6b2e4f5c2a965d7b77dc7fda 100644 (file)
--- a/lib/debug.c
+++ b/lib/debug.c
@@ -49,7 +49,7 @@ _gnutls_packet2str (content_type_t packet)
   switch (packet)
     {
     case GNUTLS_CHANGE_CIPHER_SPEC:
-      return "Change Cipher Spec";
+      return "ChangeCipherSpec";
     case GNUTLS_ALERT:
       return "Alert";
     case GNUTLS_HANDSHAKE:

diff --git a/lib/gnutls_buffers.c b/lib/gnutls_buffers.c
index 7cbd635263eb296ee7e2245ebc58f32b8ff42529..d95719719fa6c01bba024e0bf3ce5662aca71bba 100644 (file)
--- a/lib/gnutls_buffers.c
+++ b/lib/gnutls_buffers.c
@@ -51,6 +51,7 @@
 #include <gnutls_constate.h> /* gnutls_epoch_get */
 #include <errno.h>
 #include <system.h>
+#include "debug.h"
 
 #ifndef EAGAIN
 #define EAGAIN EWOULDBLOCK
@@ -600,7 +601,6 @@ _gnutls_io_write_flush (gnutls_session_t session)
   return sent;
 }
 
-#include "debug.h"
 /* Checks whether there are received data within
  * a timeframe.
  *

diff --git a/lib/gnutls_dtls.c b/lib/gnutls_dtls.c
index 5c6c333b78f3347fdd42a73ad92f4eadf963f624..5b945fd3124cd08cd328dabd651f6189d16ad74b 100644 (file)
--- a/lib/gnutls_dtls.c
+++ b/lib/gnutls_dtls.c
@@ -179,6 +179,7 @@ int ret;
    * non blocking way, check if it is time to retransmit or just
    * return.
    */
+
   if (session->internals.dtls.flight_init != 0 && session->internals.dtls.blocking == 0)
     {
       /* just in case previous run was interrupted */
@@ -205,11 +206,8 @@ int ret;
               goto cleanup;
             }
         }
-      else
-        return ret;
     }
 
-
   do 
     {
       if (now-session->internals.dtls.handshake_start_time >= session->internals.dtls.total_timeout_ms/1000) 
@@ -233,7 +231,7 @@ int ret;
           session->internals.dtls.handshake_last_call = now;
           session->internals.dtls.actual_retrans_timeout_ms = session->internals.dtls.retrans_timeout_ms;
 
-          if (last_type == GNUTLS_HANDSHAKE_FINISHED && _dtls_is_async(session))
+          if (last_type == GNUTLS_HANDSHAKE_FINISHED)
             {
               /* we cannot do anything here. We just return 0 and
                * if a retransmission occurs because peer didn't receive it
@@ -243,8 +241,6 @@ int ret;
             }
           else
             session->internals.dtls.last_flight = 0;
-
-
         }
 
       ret = _gnutls_io_write_flush (session);
@@ -252,7 +248,7 @@ int ret;
         return gnutls_assert_val(ret);
 
       /* last message in handshake -> no ack */
-      if (session->internals.dtls.last_flight != 0)
+      if (session->internals.dtls.last_flight != 0 && _dtls_is_async(session))
         {
           /* we cannot do anything here. We just return 0 and
            * if a retransmission occurs because peer didn't receive it
@@ -321,12 +317,13 @@ static void rot_window(gnutls_session_t session, int places)
 int _dtls_record_check(gnutls_session_t session, uint64 * _seq)
 {
 uint64_t seq = 0, diff;
-int i, offset = 0;
+unsigned int i, offset = 0;
 
-  for (i=0;i<8;i++) 
+  seq |= _seq->i[0] & 0xff;
+  for (i=1;i<8;i++) 
     {
-      seq |= _seq->i[i];
       seq <<= 8;
+      seq |= _seq->i[i] & 0xff;
     }
 
   if (window_size == 0)
@@ -341,9 +338,10 @@ int i, offset = 0;
       return -1;
     }
 
-  if (window_size == DTLS_RECORD_WINDOW_SIZE) {
-    rot_window(session, MOVE_SIZE);
-  }
+  if (window_size == DTLS_RECORD_WINDOW_SIZE) 
+    {
+      rot_window(session, MOVE_SIZE);
+    }
 
   if (seq < window_table[window_size-1])
     {
@@ -352,19 +350,34 @@ int i, offset = 0;
 
       if (diff >= window_size) 
         {
+          /* Probably an epoch change. Check if we can fit it */
+          if (window_table[0] == 0)
+            {
+              window_table[0] = seq;
+              return 0;
+            }
+          
+          for (i=0;i<window_size-1;i++)
+            {
+              if (seq == window_table[i])
+                return -1;
+              if (seq == window_table[i] + 1)
+                {
+                  if (seq == window_table[i+1])
+                    return -1;
+                  window_table[i+1] = seq;
+                  return 0;
+                }
+            }
           return -1;
         }
 
       offset = window_size-1-diff;
 
       if (window_table[offset] == seq)
-        {
-          return -1;
-        }
+        return -1;
       else
-        {
-          window_table[offset] = seq;
-        }
+        window_table[offset] = seq;
     }
   else /* seq >= last */
     {

diff --git a/lib/gnutls_record.c b/lib/gnutls_record.c
index 17cad7f251db5d05af0254c8b6ff6f46a2a4c1c3..7510fbf1db540aa3fd3afe3cee4e39a179d059ff 100644 (file)
--- a/lib/gnutls_record.c
+++ b/lib/gnutls_record.c
@@ -669,6 +669,12 @@ record_add_to_buffers (gnutls_session_t session,
            */
           if (IS_DTLS(session))
             {
+              if (type == GNUTLS_CHANGE_CIPHER_SPEC)
+                {
+                  ret = gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET);
+                  goto unexpected_packet;
+                }
+                
               if (_dtls_is_async(session) && _dtls_async_timer_active(session))
                 {
                   ret = _dtls_retransmit(session);
@@ -996,6 +1002,8 @@ begin:
   if (ret < 0)
     {
       gnutls_assert();
+      _gnutls_audit_log(session, "Discarded message[%u] due to invalid decryption\n", 
+            (unsigned int)_gnutls_uint64touint32 (packet_sequence));
       goto sanity_check_error;
     }
 
@@ -1008,8 +1016,8 @@ begin:
       ret = _dtls_record_check(session, packet_sequence);
       if (ret < 0)
         {
-          _gnutls_audit_log(session, "Discarded duplicate message[%u]\n",
-            (unsigned int) _gnutls_uint64touint32 (packet_sequence));
+          _gnutls_audit_log(session, "Discarded duplicate message[%u]: %s\n",
+            (unsigned int) _gnutls_uint64touint32 (packet_sequence), _gnutls_packet2str (record.type));
           goto sanity_check_error;
         }
     }
@@ -1077,8 +1085,6 @@ sanity_check_error:
   if (IS_DTLS(session))
     {
       session->internals.dtls.packets_dropped++;
-      _gnutls_audit_log(session, "Discarded message[%u] due to invalid decryption\n", 
-            (unsigned int)_gnutls_uint64touint32 (packet_sequence));
       ret = gnutls_assert_val(GNUTLS_E_AGAIN);
       goto cleanup;
     }