From 4519ed70ffbb48c8f92709af462f8499e78f31f3 Mon Sep 17 00:00:00 2001
From: Pekka Riikonen <priikone@silcnet.org>
Date: Sat, 16 Dec 2000 15:34:19 +0000
Subject: [PATCH] 	Implemented version string checking to client and
 server.

---
 CHANGES                   |  6 ++++++
 apps/silcd/protocol.c     | 18 ++++++++++++++++--
 lib/silcclient/protocol.c | 25 +++++++++++++++++++++++--
 lib/silcske/silcske.c     |  9 ++++++---
 4 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/CHANGES b/CHANGES
index dcfec656..426d317c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,9 @@
+Sat Dec 16 17:39:54 EET 2000  Pekka Riikonen <priikone@poseidon.pspt.fi>
+
+	* Implemented version string checking to both client and server.
+	  The check is incomplete currently due to the abnormal version 
+	  strings used in development version of SILC.
+
 Fri Dec 15 15:55:12 EET 2000  Pekka Riikonen <priikone@poseidon.pspt.fi>
 
 	* Changed char *data to unsigned char *data in ID Cache system to
diff --git a/apps/silcd/protocol.c b/apps/silcd/protocol.c
index 685b5ab6..fbe1f566 100644
--- a/apps/silcd/protocol.c
+++ b/apps/silcd/protocol.c
@@ -115,12 +115,26 @@ static void silc_server_protocol_ke_set_keys(SilcSKE ske,
   sock->user_data = (void *)conn_data;
 }
 
-/* XXX TODO */
+/* Check remote host version string */
 
 SilcSKEStatus silc_ske_check_version(SilcSKE ske, unsigned char *version,
 				     unsigned int len)
 {
-  return SILC_SKE_STATUS_OK;
+  SilcSKEStatus status = SILC_SKE_STATUS_OK;
+
+  /* Check for initial version string */
+  if (!strstr(version, "SILC-1.0-"))
+    status = SILC_SKE_STATUS_BAD_VERSION;
+
+  /* Check software version */
+
+  if (len < strlen(silc_version_string))
+    status = SILC_SKE_STATUS_BAD_VERSION;
+
+  /* XXX for now there is no other tests due to the abnormal version
+     string that is used */
+
+  return status;
 }
 
 /* Performs key exchange protocol. This is used for both initiator
diff --git a/lib/silcclient/protocol.c b/lib/silcclient/protocol.c
index bd52fcc5..fe7a3544 100644
--- a/lib/silcclient/protocol.c
+++ b/lib/silcclient/protocol.c
@@ -119,12 +119,32 @@ static void silc_client_protocol_ke_set_keys(SilcSKE ske,
   silc_hmac_set_key(conn->hmac, keymat->hmac_key, keymat->hmac_key_len);
 }
 
-/* XXX TODO */
+/* Checks the version string of the server. */
 
 SilcSKEStatus silc_ske_check_version(SilcSKE ske, unsigned char *version,
 				     unsigned int len)
 {
-  return SILC_SKE_STATUS_OK;
+  SilcSocketConnection conn = (SilcSocketConnection)ske->sock->user_data;
+  SilcClient client = (SilcClient)ske->user_data;
+  SilcSKEStatus status = SILC_SKE_STATUS_OK;
+
+  /* Check for initial version string */
+  if (!strstr(version, "SILC-1.0-"))
+    status = SILC_SKE_STATUS_BAD_VERSION;
+
+  /* Check software version */
+
+  if (len < strlen(silc_version_string))
+    status = SILC_SKE_STATUS_BAD_VERSION;
+
+  /* XXX for now there is no other tests due to the abnormal version
+     string that is used */
+
+  if (status != SILC_SKE_STATUS_OK)
+    client->ops->say(client, conn, 
+		     "We don't support server version `%s'", version);
+
+  return status;
 }
 
 /* Performs key exchange protocol. This is used for both initiator
@@ -156,6 +176,7 @@ SILC_TASK_CALLBACK(silc_client_protocol_key_exchange)
       ske = silc_ske_alloc();
       ctx->ske = ske;
       ske->rng = client->rng;
+      ske->user_data = (void *)client;
       
       if (ctx->responder == TRUE) {
 #if 0
diff --git a/lib/silcske/silcske.c b/lib/silcske/silcske.c
index 0dac0633..34c4c167 100644
--- a/lib/silcske/silcske.c
+++ b/lib/silcske/silcske.c
@@ -775,6 +775,7 @@ silc_ske_select_security_properties(SilcSKE ske,
 				    SilcSKEStartPayload *payload,
 				    SilcSKEStartPayload *remote_payload)
 {
+  SilcSKEStatus status;
   SilcSKEStartPayload *rp;
   char *cp;
   int len;
@@ -783,6 +784,11 @@ silc_ske_select_security_properties(SilcSKE ske,
 
   rp = remote_payload;
 
+  /* Check version string */
+  status = silc_ske_check_version(ske, rp->version, rp->version_len);
+  if (status != SILC_SKE_STATUS_OK)
+    return status;
+
   /* Flags are returned unchanged. */
   payload->flags = rp->flags;
 
@@ -791,9 +797,6 @@ silc_ske_select_security_properties(SilcSKE ske,
   payload->cookie_len = SILC_SKE_COOKIE_LEN;
   memcpy(payload->cookie, rp->cookie, SILC_SKE_COOKIE_LEN);
 
-  /* Check version string */
-  silc_ske_check_version(ske, rp->version, rp->version_len);
-
   /* Put our version to our reply */
   payload->version = strdup(version);
   payload->version_len = strlen(version);
-- 
2.24.0