Prevent possible buffer overflows when using very large (>= 8192 bit) RSA keys.

[tinc] / src / protocol_auth.c

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index 5e960ea..c44c6d0 100644 (file)
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -1,7 +1,7 @@
 /*
     protocol_auth.c -- handle the meta-protocol, authentication
-    Copyright (C) 1999-2003 Ivo Timmermans <ivo@o2w.nl>,
-                  2000-2003 Guus Sliepen <guus@sliepen.eu.org>
+    Copyright (C) 1999-2005 Ivo Timmermans <ivo@tinc-vpn.org>,
+                  2000-2005 Guus Sliepen <guus@tinc-vpn.org>
 
     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
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id: protocol_auth.c,v 1.1.4.32 2003/12/20 21:09:33 guus Exp $
+    $Id$
 */
 
 #include "system.h"
@@ -76,8 +76,11 @@ bool id_h(connection_t *c)
                                   c->name);
                        return false;
                }
-       } else
+       } else {
+               if(c->name)
+                       free(c->name);
                c->name = xstrdup(name);
+       }
 
        /* Check if version matches */
 
@@ -115,7 +118,7 @@ bool id_h(connection_t *c)
 
 bool send_metakey(connection_t *c)
 {
-       char buffer[MAX_STRING_SIZE];
+       char *buffer;
        int len;
        bool x;
 
@@ -125,6 +128,8 @@ bool send_metakey(connection_t *c)
 
        /* Allocate buffers for the meta key */
 
+       buffer = alloca(2 * len + 1);
+       
        if(!c->outkey)
                c->outkey = xmalloc(len);
 
@@ -299,7 +304,7 @@ bool metakey_h(connection_t *c)
 
 bool send_challenge(connection_t *c)
 {
-       char buffer[MAX_STRING_SIZE];
+       char *buffer;
        int len;
 
        cp();
@@ -310,6 +315,8 @@ bool send_challenge(connection_t *c)
 
        /* Allocate buffers for the challenge */
 
+       buffer = alloca(2 * len + 1);
+
        if(!c->hischallenge)
                c->hischallenge = xmalloc(len);
 
@@ -476,8 +483,10 @@ bool send_ack(connection_t *c)
        if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
                c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
 
-       if((get_config_bool(lookup_config(c->config_tree, "PMTUDiscovery"), &choice) && choice) || myself->options & OPTION_DONTFRAGMENT)
-               c->options |= OPTION_DONTFRAGMENT;
+       if((get_config_bool(lookup_config(c->config_tree, "PMTUDiscovery"), &choice) && choice) || myself->options & OPTION_PMTU_DISCOVERY)
+               c->options |= OPTION_PMTU_DISCOVERY;
+
+       get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
 
        return send_request(c, "%d %s %d %lx", ACK, myport, c->estimated_weight, c->options);
 }
@@ -519,7 +528,7 @@ bool ack_h(connection_t *c)
 {
        char hisport[MAX_STRING_SIZE];
        char *hisaddress, *dummy;
-       int weight;
+       int weight, mtu;
        long int options;
        node_t *n;
 
@@ -554,6 +563,12 @@ bool ack_h(connection_t *c)
        c->node = n;
        c->options |= options;
 
+       if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
+               n->mtu = mtu;
+
+       if(get_config_int(lookup_config(myself->connection->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
+               n->mtu = mtu;
+
        /* Activate this connection */
 
        c->allow_request = ALL;