SKE: Verify initiator's public key always
[silc.git] / lib / silcske / silcske.c
index 69b43607173a3e5f0b190fb72277562370580d78..caf2579628bf9a1a426057a5179f2949dfa5d07e 100644 (file)
@@ -4,7 +4,7 @@
 
   Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 2000 - 2007 Pekka Riikonen
+  Copyright (C) 2000 - 2008 Pekka Riikonen
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -671,19 +671,23 @@ static SilcSKEStatus silc_ske_make_hash(SilcSKE ske,
 {
   SilcSKEStatus status = SILC_SKE_STATUS_OK;
   SilcBuffer buf;
-  unsigned char *e, *f, *KEY;
-  SilcUInt32 e_len, f_len, KEY_len;
+  unsigned char *e, *f, *KEY, *s_data;
+  SilcUInt32 e_len, f_len, KEY_len, s_len;
   int ret;
 
   SILC_LOG_DEBUG(("Start"));
 
   if (initiator == FALSE) {
+    s_data = (ske->start_payload_copy ?
+            silc_buffer_data(ske->start_payload_copy) : NULL);
+    s_len = (ske->start_payload_copy ?
+            silc_buffer_len(ske->start_payload_copy) : 0);
     e = silc_mp_mp2bin(&ske->ke1_payload->x, 0, &e_len);
     f = silc_mp_mp2bin(&ske->ke2_payload->x, 0, &f_len);
     KEY = silc_mp_mp2bin(ske->KEY, 0, &KEY_len);
 
     /* Format the buffer used to compute the hash value */
-    buf = silc_buffer_alloc_size(silc_buffer_len(ske->start_payload_copy) +
+    buf = silc_buffer_alloc_size(s_len +
                                 ske->ke2_payload->pk_len +
                                 ske->ke1_payload->pk_len +
                                 e_len + f_len + KEY_len);
@@ -694,28 +698,24 @@ static SilcSKEStatus silc_ske_make_hash(SilcSKE ske,
     if (!ske->ke1_payload->pk_data) {
       ret =
        silc_buffer_format(buf,
-                          SILC_STR_UI_XNSTRING(
-                                  ske->start_payload_copy->data,
-                                  silc_buffer_len(ske->start_payload_copy)),
-                          SILC_STR_UI_XNSTRING(ske->ke2_payload->pk_data,
-                                               ske->ke2_payload->pk_len),
-                          SILC_STR_UI_XNSTRING(e, e_len),
-                          SILC_STR_UI_XNSTRING(f, f_len),
-                          SILC_STR_UI_XNSTRING(KEY, KEY_len),
+                          SILC_STR_DATA(s_data, s_len),
+                          SILC_STR_DATA(ske->ke2_payload->pk_data,
+                                        ske->ke2_payload->pk_len),
+                          SILC_STR_DATA(e, e_len),
+                          SILC_STR_DATA(f, f_len),
+                          SILC_STR_DATA(KEY, KEY_len),
                           SILC_STR_END);
     } else {
       ret =
        silc_buffer_format(buf,
-                          SILC_STR_UI_XNSTRING(
-                                  ske->start_payload_copy->data,
-                                  silc_buffer_len(ske->start_payload_copy)),
-                          SILC_STR_UI_XNSTRING(ske->ke2_payload->pk_data,
-                                               ske->ke2_payload->pk_len),
-                          SILC_STR_UI_XNSTRING(ske->ke1_payload->pk_data,
-                                               ske->ke1_payload->pk_len),
-                          SILC_STR_UI_XNSTRING(e, e_len),
-                          SILC_STR_UI_XNSTRING(f, f_len),
-                          SILC_STR_UI_XNSTRING(KEY, KEY_len),
+                          SILC_STR_DATA(s_data, s_len),
+                          SILC_STR_DATA(ske->ke2_payload->pk_data,
+                                        ske->ke2_payload->pk_len),
+                          SILC_STR_DATA(ske->ke1_payload->pk_data,
+                                        ske->ke1_payload->pk_len),
+                          SILC_STR_DATA(e, e_len),
+                          SILC_STR_DATA(f, f_len),
+                          SILC_STR_DATA(KEY, KEY_len),
                           SILC_STR_END);
     }
     if (ret == -1) {
@@ -736,21 +736,23 @@ static SilcSKEStatus silc_ske_make_hash(SilcSKE ske,
     silc_free(f);
     silc_free(KEY);
   } else {
+    s_data = (ske->start_payload_copy ?
+            silc_buffer_data(ske->start_payload_copy) : NULL);
+    s_len = (ske->start_payload_copy ?
+            silc_buffer_len(ske->start_payload_copy) : 0);
     e = silc_mp_mp2bin(&ske->ke1_payload->x, 0, &e_len);
 
-    buf = silc_buffer_alloc_size(silc_buffer_len(ske->start_payload_copy) +
-                                ske->ke1_payload->pk_len + e_len);
+    buf = silc_buffer_alloc_size(s_len + ske->ke1_payload->pk_len + e_len);
     if (!buf)
       return SILC_SKE_STATUS_OUT_OF_MEMORY;
 
     /* Format the buffer used to compute the hash value */
     ret =
       silc_buffer_format(buf,
-                        SILC_STR_UI_XNSTRING(ske->start_payload_copy->data,
-                                    silc_buffer_len(ske->start_payload_copy)),
-                        SILC_STR_UI_XNSTRING(ske->ke1_payload->pk_data,
-                                             ske->ke1_payload->pk_len),
-                        SILC_STR_UI_XNSTRING(e, e_len),
+                        SILC_STR_DATA(s_data, s_len),
+                        SILC_STR_DATA(ske->ke1_payload->pk_data,
+                                      ske->ke1_payload->pk_len),
+                        SILC_STR_DATA(e, e_len),
                         SILC_STR_END);
     if (ret == -1) {
       silc_buffer_free(buf);
@@ -1611,14 +1613,16 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase4)
 
   payload = ske->ke2_payload;
 
+  /* Compute the HASH value */
+  SILC_LOG_DEBUG(("Computing HASH value"));
+  status = silc_ske_make_hash(ske, hash, &hash_len, FALSE);
+  if (status != SILC_SKE_STATUS_OK)
+    goto err;
+  ske->hash = silc_memdup(hash, hash_len);
+  ske->hash_len = hash_len;
+
   if (ske->prop->public_key) {
     SILC_LOG_DEBUG(("Public key is authentic"));
-
-    /* Compute the hash value */
-    status = silc_ske_make_hash(ske, hash, &hash_len, FALSE);
-    if (status != SILC_SKE_STATUS_OK)
-      goto err;
-
     SILC_LOG_DEBUG(("Verifying signature (HASH)"));
 
     /* Verify signature */
@@ -1630,9 +1634,6 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase4)
     }
 
     SILC_LOG_DEBUG(("Signature is Ok"));
-
-    ske->hash = silc_memdup(hash, hash_len);
-    ske->hash_len = hash_len;
     memset(hash, 'F', hash_len);
   }
 
@@ -1884,6 +1885,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase1)
   SilcSKEStatus status;
   SilcSKEStartPayload remote_payload = NULL;
   SilcBuffer packet_buf = &ske->packet->buffer;
+  SilcID id;
 
   SILC_LOG_DEBUG(("Start"));
 
@@ -1898,6 +1900,19 @@ SILC_FSM_STATE(silc_ske_st_responder_phase1)
     return SILC_FSM_CONTINUE;
   }
 
+  /* Get remote ID and set it to stream */
+  if (ske->packet->src_id_len) {
+    silc_id_str2id(ske->packet->src_id, ske->packet->src_id_len,
+                  ske->packet->src_id_type,
+                  (ske->packet->src_id_type == SILC_ID_SERVER ?
+                   (void *)&id.u.server_id : (void *)&id.u.client_id),
+                  (ske->packet->src_id_type == SILC_ID_SERVER ?
+                   sizeof(id.u.server_id) : sizeof(id.u.client_id)));
+    silc_packet_set_ids(ske->stream, 0, NULL, ske->packet->src_id_type,
+                       (ske->packet->src_id_type == SILC_ID_SERVER ?
+                        (void *)&id.u.server_id : (void *)&id.u.client_id));
+  }
+
   /* Take a copy of the payload buffer for future use. It is used to
      compute the HASH value. */
   ske->start_payload_copy = silc_buffer_copy(packet_buf);
@@ -2011,15 +2026,9 @@ SILC_FSM_STATE(silc_ske_st_responder_phase2)
   silc_packet_free(ske->packet);
   ske->packet = NULL;
 
-  /* Verify the received public key and verify the signature if we are
-     doing mutual authentication. */
-  if (ske->start_payload &&
-      ske->start_payload->flags & SILC_SKE_SP_FLAG_MUTUAL) {
-
-    SILC_LOG_DEBUG(("We are doing mutual authentication"));
-
-    if (!recv_payload->pk_data && (ske->callbacks->verify_key ||
-                                  ske->repository)) {
+  /* Verify public key, except in rekey, when it is not sent */
+  if (!ske->rekey) {
+    if (!recv_payload->pk_data) {
       /** Public key not provided */
       SILC_LOG_ERROR(("Remote end did not send its public key (or "
                      "certificate), even though we require it"));
@@ -2029,8 +2038,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase2)
     }
 
     /* Decode the remote's public key */
-    if (recv_payload->pk_data &&
-       !silc_pkcs_public_key_alloc(recv_payload->pk_type,
+    if (!silc_pkcs_public_key_alloc(recv_payload->pk_type,
                                    recv_payload->pk_data,
                                    recv_payload->pk_len,
                                    &ske->prop->public_key)) {
@@ -2041,39 +2049,36 @@ SILC_FSM_STATE(silc_ske_st_responder_phase2)
       return SILC_FSM_CONTINUE;
     }
 
-    if (ske->prop->public_key && (ske->callbacks->verify_key ||
-                                 ske->repository)) {
-      SILC_LOG_DEBUG(("Verifying public key"));
+    SILC_LOG_DEBUG(("Verifying public key"));
 
-      /** Waiting public key verification */
-      silc_fsm_next(fsm, silc_ske_st_responder_phase4);
+    /** Waiting public key verification */
+    silc_fsm_next(fsm, silc_ske_st_responder_phase4);
 
-      /* If repository is provided, verify the key from there. */
-      if (ske->repository) {
-       SilcSKRFind find;
+    /* If repository is provided, verify the key from there. */
+    if (ske->repository) {
+      SilcSKRFind find;
 
-       find = silc_skr_find_alloc();
-       if (!find) {
-         ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
-         silc_fsm_next(fsm, silc_ske_st_responder_error);
-         return SILC_FSM_CONTINUE;
-       }
-       silc_skr_find_set_pkcs_type(find,
-                                   silc_pkcs_get_type(ske->prop->public_key));
-       silc_skr_find_set_public_key(find, ske->prop->public_key);
-       silc_skr_find_set_usage(find, SILC_SKR_USAGE_KEY_AGREEMENT);
-
-       /* Find key from repository */
-       SILC_FSM_CALL(silc_skr_find(ske->repository,
-                                   silc_fsm_get_schedule(fsm), find,
-                                   silc_ske_skr_callback, ske));
-      } else {
-       /* Verify from application */
+      find = silc_skr_find_alloc();
+      if (!find) {
+       ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+       silc_fsm_next(fsm, silc_ske_st_responder_error);
+       return SILC_FSM_CONTINUE;
+      }
+      silc_skr_find_set_pkcs_type(find,
+                                 silc_pkcs_get_type(ske->prop->public_key));
+      silc_skr_find_set_public_key(find, ske->prop->public_key);
+      silc_skr_find_set_usage(find, SILC_SKR_USAGE_KEY_AGREEMENT);
+
+      /* Find key from repository */
+      SILC_FSM_CALL(silc_skr_find(ske->repository,
+                                 silc_fsm_get_schedule(fsm), find,
+                                 silc_ske_skr_callback, ske));
+    } else {
+      /* Verify from application */
+      if (ske->callbacks->verify_key)
        SILC_FSM_CALL(ske->callbacks->verify_key(ske, ske->prop->public_key,
                                                 ske->callbacks->context,
                                                 silc_ske_pk_verified, NULL));
-      }
-      /* NOT REACHED */
     }
   }
 
@@ -2114,7 +2119,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase4)
     unsigned char hash[SILC_HASH_MAXLEN];
     SilcUInt32 hash_len;
 
-    SILC_LOG_DEBUG(("Public key is authentic"));
+    SILC_LOG_DEBUG(("We are doing mutual authentication"));
 
     /* Compute the hash value */
     status = silc_ske_make_hash(ske, hash, &hash_len, TRUE);
@@ -2209,22 +2214,23 @@ SILC_FSM_STATE(silc_ske_st_responder_phase5)
     }
     ske->ke2_payload->pk_data = pk;
     ske->ke2_payload->pk_len = pk_len;
+  }
 
-    SILC_LOG_DEBUG(("Computing HASH value"));
-
-    /* Compute the hash value */
-    memset(hash, 0, sizeof(hash));
-    status = silc_ske_make_hash(ske, hash, &hash_len, FALSE);
-    if (status != SILC_SKE_STATUS_OK) {
-      /** Error computing hash */
-      ske->status = status;
-      silc_fsm_next(fsm, silc_ske_st_responder_error);
-      return SILC_FSM_CONTINUE;
-    }
+  SILC_LOG_DEBUG(("Computing HASH value"));
 
-    ske->hash = silc_memdup(hash, hash_len);
-    ske->hash_len = hash_len;
+  /* Compute the hash value */
+  memset(hash, 0, sizeof(hash));
+  status = silc_ske_make_hash(ske, hash, &hash_len, FALSE);
+  if (status != SILC_SKE_STATUS_OK) {
+    /** Error computing hash */
+    ske->status = status;
+    silc_fsm_next(fsm, silc_ske_st_responder_error);
+    return SILC_FSM_CONTINUE;
+  }
+  ske->hash = silc_memdup(hash, hash_len);
+  ske->hash_len = hash_len;
 
+  if (ske->public_key && ske->private_key) {
     SILC_LOG_DEBUG(("Signing HASH value"));
 
     /* Sign the hash value */
@@ -2262,7 +2268,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase5)
 
   silc_buffer_free(payload_buf);
 
-  /* In case we are doing rekey move to finish it.  */
+  /* In case we are doing rekey move to finish it. */
   if (ske->rekey) {
     /** Finish rekey */
     silc_fsm_next(fsm, silc_ske_st_rekey_responder_done);
@@ -2461,6 +2467,13 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_start)
     return SILC_FSM_CONTINUE;
   }
 
+  if (!silc_hash_alloc(ske->rekey->hash, &ske->prop->hash)) {
+    /** Cannot allocate hash */
+    ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+    silc_fsm_next(fsm, silc_ske_st_initiator_error);
+    return SILC_FSM_CONTINUE;
+  }
+
   /* Send REKEY packet to start rekey protocol */
   if (!silc_ske_packet_send(ske, SILC_PACKET_REKEY, 0, NULL, 0)) {
     /** Error sending packet */
@@ -2506,13 +2519,7 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_done)
   silc_packet_get_keys(ske->stream, &send_key, NULL, &hmac_send, NULL);
   key_len = silc_cipher_get_key_len(send_key);
   block_len = silc_cipher_get_block_len(send_key);
-
-  if (!silc_hash_alloc(ske->rekey->hash, &hash)) {
-    /** Cannot allocate hash */
-    ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
-    silc_fsm_next(fsm, silc_ske_st_initiator_error);
-    return SILC_FSM_CONTINUE;
-  }
+  hash = ske->prop->hash;
   hash_len = silc_hash_len(hash);
 
   /* Process key material */
@@ -2543,17 +2550,21 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_done)
 
   ske->prop->cipher = send_key;
   ske->prop->hmac = hmac_send;
-  ske->prop->hash = hash;
 
   /* Get sending keys */
   if (!silc_ske_set_keys(ske, ske->keymat, ske->prop, &send_key, NULL,
                         &hmac_send, NULL, NULL)) {
     /** Cannot get keys */
     ske->status = SILC_SKE_STATUS_ERROR;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
 
+  ske->prop->cipher = NULL;
+  ske->prop->hmac = NULL;
+
   /* Set the new keys into use.  This will also send REKEY_DONE packet.  Any
      packet sent after this call will be protected with the new keys. */
   if (!silc_packet_set_keys(ske->stream, send_key, NULL, hmac_send, NULL,
@@ -2561,6 +2572,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_done)
     /** Cannot set keys */
     SILC_LOG_DEBUG(("Cannot set new keys, error sending REKEY_DONE"));
     ske->status = SILC_SKE_STATUS_ERROR;
+    silc_cipher_free(send_key);
+    silc_hmac_free(hmac_send);
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2597,6 +2610,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_end)
                         NULL, &hmac_receive, NULL)) {
     /** Cannot get keys */
     ske->status = SILC_SKE_STATUS_ERROR;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2608,6 +2623,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_end)
     /** Cannot set keys */
     SILC_LOG_DEBUG(("Cannot set new keys"));
     ske->status = SILC_SKE_STATUS_ERROR;
+    silc_cipher_free(receive_key);
+    silc_hmac_free(hmac_receive);
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2619,6 +2636,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_initiator_end)
   if (!rekey) {
     /** No memory */
     ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2647,8 +2666,11 @@ silc_ske_rekey_initiator(SilcSKE ske,
 {
   SILC_LOG_DEBUG(("Start SKE rekey as initator"));
 
-  if (!ske || !stream || !rekey)
+  if (!ske || !stream || !rekey) {
+    SILC_LOG_ERROR(("Missing arguments to silc_ske_rekey_initiator"));
+    SILC_ASSERT(rekey);
     return NULL;
+  }
 
   if (!silc_async_init(&ske->op, silc_ske_abort, NULL, ske))
     return NULL;
@@ -2696,7 +2718,6 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_wait)
   silc_schedule_task_add_timeout(ske->schedule, silc_ske_timeout,
                                 ske, 30, 0);
 
-
   silc_fsm_next(fsm, silc_ske_st_rekey_responder_start);
 
   /* If REKEY packet already received process it directly */
@@ -2732,6 +2753,13 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_start)
     return SILC_FSM_CONTINUE;
   }
 
+  if (!silc_hash_alloc(ske->rekey->hash, &ske->prop->hash)) {
+    /** Cannot allocate hash */
+    ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+    silc_fsm_next(fsm, silc_ske_st_responder_error);
+    return SILC_FSM_CONTINUE;
+  }
+
   /* If doing rekey without PFS, move directly to the end of the protocol. */
   if (!ske->rekey->pfs) {
     /** Rekey without PFS */
@@ -2768,13 +2796,7 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_done)
   silc_packet_get_keys(ske->stream, &send_key, NULL, &hmac_send, NULL);
   key_len = silc_cipher_get_key_len(send_key);
   block_len = silc_cipher_get_block_len(send_key);
-
-  if (!silc_hash_alloc(ske->rekey->hash, &hash)) {
-    /** Cannot allocate hash */
-    ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
-    silc_fsm_next(fsm, silc_ske_st_responder_error);
-    return SILC_FSM_CONTINUE;
-  }
+  hash = ske->prop->hash;
   hash_len = silc_hash_len(hash);
 
   /* Process key material */
@@ -2805,17 +2827,21 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_done)
 
   ske->prop->cipher = send_key;
   ske->prop->hmac = hmac_send;
-  ske->prop->hash = hash;
 
   /* Get sending keys */
   if (!silc_ske_set_keys(ske, ske->keymat, ske->prop, &send_key, NULL,
                         &hmac_send, NULL, NULL)) {
     /** Cannot get keys */
     ske->status = SILC_SKE_STATUS_ERROR;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
   }
 
+  ske->prop->cipher = NULL;
+  ske->prop->hmac = NULL;
+
   /* Set the new keys into use.  This will also send REKEY_DONE packet.  Any
      packet sent after this call will be protected with the new keys. */
   if (!silc_packet_set_keys(ske->stream, send_key, NULL, hmac_send, NULL,
@@ -2823,6 +2849,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_done)
     /** Cannot set keys */
     SILC_LOG_DEBUG(("Cannot set new keys, error sending REKEY_DONE"));
     ske->status = SILC_SKE_STATUS_ERROR;
+    silc_cipher_free(send_key);
+    silc_hmac_free(hmac_send);
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2859,6 +2887,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_end)
                         NULL, &hmac_receive, NULL)) {
     /** Cannot get keys */
     ske->status = SILC_SKE_STATUS_ERROR;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2870,6 +2900,10 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_end)
     /** Cannot set keys */
     SILC_LOG_DEBUG(("Cannot set new keys"));
     ske->status = SILC_SKE_STATUS_ERROR;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
+    silc_cipher_free(receive_key);
+    silc_hmac_free(hmac_receive);
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2881,6 +2915,8 @@ SILC_FSM_STATE(silc_ske_st_rekey_responder_end)
   if (!rekey) {
     /** No memory */
     ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+    ske->prop->cipher = NULL;
+    ske->prop->hmac = NULL;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
   }
@@ -2971,7 +3007,7 @@ silc_ske_process_key_material_data(unsigned char *data,
     return NULL;
   silc_buffer_format(buf,
                     SILC_STR_UI_CHAR(0),
-                    SILC_STR_UI_XNSTRING(data, data_len),
+                    SILC_STR_DATA(data, data_len),
                     SILC_STR_END);
 
   /* Take IVs */
@@ -3010,8 +3046,8 @@ silc_ske_process_key_material_data(unsigned char *data,
     if (!dist)
       return NULL;
     silc_buffer_format(dist,
-                      SILC_STR_UI_XNSTRING(data, data_len),
-                      SILC_STR_UI_XNSTRING(k1, hash_len),
+                      SILC_STR_DATA(data, data_len),
+                      SILC_STR_DATA(k1, hash_len),
                       SILC_STR_END);
     memset(k2, 0, sizeof(k2));
     silc_hash_make(hash, dist->data, silc_buffer_len(dist), k2);
@@ -3021,7 +3057,7 @@ silc_ske_process_key_material_data(unsigned char *data,
     silc_buffer_pull_tail(dist, hash_len);
     silc_buffer_pull(dist, data_len + hash_len);
     silc_buffer_format(dist,
-                      SILC_STR_UI_XNSTRING(k2, hash_len),
+                      SILC_STR_DATA(k2, hash_len),
                       SILC_STR_END);
     silc_buffer_push(dist, data_len + hash_len);
     memset(k3, 0, sizeof(k3));
@@ -3073,8 +3109,8 @@ silc_ske_process_key_material_data(unsigned char *data,
     if (!dist)
       return NULL;
     silc_buffer_format(dist,
-                      SILC_STR_UI_XNSTRING(data, data_len),
-                      SILC_STR_UI_XNSTRING(k1, hash_len),
+                      SILC_STR_DATA(data, data_len),
+                      SILC_STR_DATA(k1, hash_len),
                       SILC_STR_END);
     memset(k2, 0, sizeof(k2));
     silc_hash_make(hash, dist->data, silc_buffer_len(dist), k2);
@@ -3084,7 +3120,7 @@ silc_ske_process_key_material_data(unsigned char *data,
     silc_buffer_pull_tail(dist, hash_len);
     silc_buffer_pull(dist, data_len + hash_len);
     silc_buffer_format(dist,
-                      SILC_STR_UI_XNSTRING(k2, hash_len),
+                      SILC_STR_DATA(k2, hash_len),
                       SILC_STR_END);
     silc_buffer_push(dist, data_len + hash_len);
     memset(k3, 0, sizeof(k3));
@@ -3160,8 +3196,8 @@ silc_ske_process_key_material(SilcSKE ske,
   if (!buf)
     return NULL;
   silc_buffer_format(buf,
-                    SILC_STR_UI_XNSTRING(tmpbuf, klen),
-                    SILC_STR_UI_XNSTRING(ske->hash, ske->hash_len),
+                    SILC_STR_DATA(tmpbuf, klen),
+                    SILC_STR_DATA(ske->hash, ske->hash_len),
                     SILC_STR_END);
 
   /* Process the key material */
@@ -3239,7 +3275,7 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
                           SilcHmac *ret_hmac_receive,
                           SilcHash *ret_hash)
 {
-  unsigned char iv[32];
+  unsigned char iv[SILC_HASH_MAXLEN];
   SilcBool iv_included = (prop->flags & SILC_SKE_SP_FLAG_IV_INCLUDED);
 
   /* Allocate ciphers to be used in the communication */
@@ -3266,6 +3302,12 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
       return FALSE;
   }
 
+  /* Allocate hash */
+  if (ret_hash) {
+    if (!silc_hash_alloc(silc_hash_get_name(prop->hash), ret_hash))
+      return FALSE;
+  }
+
   /* Set key material */
   memset(iv, 0, sizeof(iv));
   if (ske->responder) {
@@ -3274,10 +3316,24 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
                          keymat->enc_key_len, TRUE);
 
       if (silc_cipher_get_mode(*ret_send_key) == SILC_CIPHER_MODE_CTR) {
-        memcpy(iv, ske->hash, 4);
-        memcpy(iv + 4, keymat->receive_iv, iv_included ? 4 : 8);
+       /* Counter mode */
+       if (!ske->rekeying) {
+         /* Set IV. */
+         memcpy(iv, ske->hash, 4);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->receive_iv, 8);
+       } else {
+         /* Rekey, recompute the truncated hash value. */
+         silc_hash_make(prop->hash, keymat->receive_iv, 8, iv);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->receive_iv, 8);
+         else
+           memset(iv + 4, 0, 12);
+       }
+
         silc_cipher_set_iv(*ret_send_key, iv);
       } else {
+       /* Other modes */
        silc_cipher_set_iv(*ret_send_key, keymat->receive_iv);
       }
     }
@@ -3286,10 +3342,24 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
                          keymat->enc_key_len, FALSE);
 
       if (silc_cipher_get_mode(*ret_receive_key) == SILC_CIPHER_MODE_CTR) {
-        memcpy(iv, ske->hash, 4);
-        memcpy(iv + 4, keymat->send_iv, iv_included ? 4 : 8);
+       /* Counter mode */
+       if (!ske->rekeying) {
+         /* Set IV. */
+         memcpy(iv, ske->hash, 4);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->send_iv, 8);
+       } else {
+         /* Rekey, recompute the truncated hash value. */
+         silc_hash_make(prop->hash, keymat->send_iv, 8, iv);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->send_iv, 8);
+         else
+           memset(iv + 4, 0, 12);
+       }
+
         silc_cipher_set_iv(*ret_receive_key, iv);
       } else {
+       /* Other modes */
        silc_cipher_set_iv(*ret_receive_key, keymat->send_iv);
       }
     }
@@ -3305,10 +3375,24 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
                          keymat->enc_key_len, TRUE);
 
       if (silc_cipher_get_mode(*ret_send_key) == SILC_CIPHER_MODE_CTR) {
-        memcpy(iv, ske->hash, 4);
-        memcpy(iv + 4, keymat->send_iv, iv_included ? 4 : 8);
+       /* Counter mode */
+       if (!ske->rekeying) {
+         /* Set IV. */
+         memcpy(iv, ske->hash, 4);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->send_iv, 8);
+       } else {
+         /* Rekey, recompute the truncated hash value. */
+         silc_hash_make(prop->hash, keymat->send_iv, 8, iv);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->send_iv, 8);
+         else
+           memset(iv + 4, 0, 12);
+       }
+
        silc_cipher_set_iv(*ret_send_key, iv);
       } else {
+       /* Other modes */
        silc_cipher_set_iv(*ret_send_key, keymat->send_iv);
       }
     }
@@ -3317,10 +3401,25 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
                          keymat->enc_key_len, FALSE);
 
       if (silc_cipher_get_mode(*ret_receive_key) == SILC_CIPHER_MODE_CTR) {
-        memcpy(iv, ske->hash, 4);
-        memcpy(iv + 4, keymat->receive_iv, iv_included ? 4 : 8);
+       /* Counter mode */
+       if (!ske->rekeying) {
+         /* Set IV.  If IV Included flag was negotiated we only set the
+            truncated hash value. */
+         memcpy(iv, ske->hash, 4);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->receive_iv, 8);
+       } else {
+         /* Rekey, recompute the truncated hash value. */
+         silc_hash_make(prop->hash, keymat->receive_iv, 8, iv);
+         if (!iv_included)
+           memcpy(iv + 4, keymat->receive_iv, 8);
+         else
+           memset(iv + 4, 0, 12);
+       }
+
        silc_cipher_set_iv(*ret_receive_key, iv);
       } else {
+       /* Other modes */
        silc_cipher_set_iv(*ret_receive_key, keymat->receive_iv);
       }
     }
@@ -3332,12 +3431,6 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
                        keymat->hmac_key_len);
   }
 
-  /* Allocate hash */
-  if (ret_hash) {
-    if (!silc_hash_alloc(silc_hash_get_name(prop->hash), ret_hash))
-      return FALSE;
-  }
-
   return TRUE;
 }