X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fprotocol.c;h=aeeec1be63be18985aa9cde7302b89b5478d4345;hp=c3681af44096e4a7d43e29d1163a6ec4bb7def7d;hb=5065ea32c32e27478d93c00a1bba0c812b7a2b8c;hpb=f25868fd2b58bc0b350a5cfaf342480f28f804cf

diff --git a/src/protocol.c b/src/protocol.c
index c3681af4..aeeec1be 100644
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -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.c,v 1.28.4.46 2000/10/28 21:05:18 guus Exp $
+    $Id: protocol.c,v 1.28.4.54 2000/11/03 22:35:11 zarq Exp $
 */
 
 #include "config.h"
@@ -37,13 +37,15 @@
 #include <netinet/in.h>
 
 #include <openssl/sha.h>
+#include <openssl/rand.h>
+#include <openssl/evp.h>
 
 #include "conf.h"
-#include "encr.h"
 #include "net.h"
 #include "netutl.h"
 #include "protocol.h"
 #include "meta.h"
+#include "connlist.h"
 
 #include "system.h"
 
@@ -108,6 +110,13 @@ cp
             syslog(LOG_DEBUG, _("Got %s from %s (%s)"),
 		   request_name[request], cl->name, cl->hostname);
 	}
+
+      if((cl->allow_request != ALL) && (cl->allow_request != request))
+        {
+          syslog(LOG_ERR, _("Unauthorized request from %s (%s)"), cl->name, cl->hostname);
+          return -1;
+        }
+
       if(request_handlers[request](cl))
 	/* Something went wrong. Probably scriptkiddies. Terminate. */
         {
@@ -122,6 +131,8 @@ cp
 	     cl->name, cl->hostname);
       return -1;
     }
+cp
+  return 0;
 }
 
 /* Connection protocol:
@@ -134,8 +145,8 @@ cp
    send_challenge(R)
                         send_chal_reply(H)
    ---------------------------------------
-   Any negotations about the meta protocol
-   encryption go here(u).
+   send_metakey(R)
+                        send_metakey(R)
    ---------------------------------------
    send_ack(u)
                         send_ack(u)
@@ -163,7 +174,7 @@ cp
 int id_h(conn_list_t *cl)
 {
   conn_list_t *old;
-  config_t *cfg;
+  config_t const *cfg;
 cp
   if(sscanf(cl->buffer, "%*d %as %d %lx %hd", &cl->name, &cl->protocol_version, &cl->options, &cl->port) != 4)
     {
@@ -214,19 +225,17 @@ cp
         }
     }
 cp    
-  if(!(cfg = get_config_val(cl->config, publickey)))
+  if((cfg = get_config_val(cl->config, publickey)))
     {
-      syslog(LOG_ERR, _("No public key known for %s (%s)"), cl->name, cl->hostname);
-      return -1;
-    }
-  else
-    {
-cp
       cl->rsa_key = RSA_new();
       BN_hex2bn(&cl->rsa_key->n, cfg->data.ptr);
       BN_hex2bn(&cl->rsa_key->e, "FFFF");
     }
-
+  else
+    {
+      syslog(LOG_ERR, _("No public key known for %s (%s)"), cl->name, cl->hostname);
+      return -1;
+    }
 cp
   return send_challenge(cl);
 }
@@ -247,10 +256,6 @@ cp
     
   cl->hischallenge = xmalloc(len);
 cp
-  /* Seed the PRNG with urandom (can't afford to block) */
-
-  RAND_load_file("/dev/urandom", 1024);
-
   /* Copy random data to the buffer */
 
   RAND_bytes(cl->hischallenge, len);
@@ -365,7 +370,7 @@ cp
   if(cl->status.outgoing)
     cl->allow_request = ID;
   else
-    cl->allow_request = ACK;
+    cl->allow_request = METAKEY;
 
 cp
   return send_request(cl, "%d %s", CHAL_REPLY, hash);
@@ -424,17 +429,142 @@ cp
    */
 cp
   if(cl->status.outgoing)
-      return send_ack(cl);
+      return send_metakey(cl);
   else
       return send_id(cl);
 }
 
+int send_metakey(conn_list_t *cl)
+{
+  char *buffer;
+  int len, x;
+cp
+  len = RSA_size(cl->rsa_key);
+
+  /* Allocate buffers for the meta key */
+
+  buffer = xmalloc(len*2+1);
+
+  if(!cl->cipher_outkey)
+    cl->cipher_outkey = xmalloc(len);
+    
+  if(!cl->cipher_outctx)
+    cl->cipher_outctx = xmalloc(sizeof(*cl->cipher_outctx));
+cp
+  /* Copy random data to the buffer */
+
+  RAND_bytes(cl->cipher_outkey, len);
+
+  cl->cipher_outkey[0] &= 0x7F;	/* FIXME: Somehow if the first byte is more than 0xD0 or something like that, decryption fails... */
+
+  if(debug_lvl >= DEBUG_SCARY_THINGS)
+    {
+      bin2hex(cl->cipher_outkey, buffer, len);
+      buffer[len*2] = '\0';
+      syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
+    }
+
+  /* Encrypt the random data */
+  
+  if(RSA_public_encrypt(len, cl->cipher_outkey, buffer, cl->rsa_key, RSA_NO_PADDING) != len)	/* NO_PADDING because the message size equals the RSA key size and it is totally random */
+    {
+      syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), cl->name, cl->hostname);
+      free(buffer);
+      return -1;
+    }
+cp
+  /* Convert the encrypted random data to a hexadecimal formatted string */
+
+  bin2hex(buffer, buffer, len);
+  buffer[len*2] = '\0';
+
+  /* Send the meta key */
+
+  if(cl->status.outgoing)
+    cl->allow_request = METAKEY;
+  else
+    cl->allow_request = ACK;
+    
+  x = send_request(cl, "%d %s", METAKEY, buffer);
+  free(buffer);
+
+  EVP_EncryptInit(cl->cipher_outctx, EVP_bf_cfb(), cl->cipher_outkey, cl->cipher_outkey + EVP_bf_cfb()->key_len);
+cp
+  return x;
+}
+
+int metakey_h(conn_list_t *cl)
+{
+  char *buffer;
+  int len;
+cp
+  if(sscanf(cl->buffer, "%*d %as", &buffer) != 1)
+    {
+       syslog(LOG_ERR, _("Got bad METAKEY from %s (%s)"), cl->name, cl->hostname);
+       return -1;
+    }
+
+  len = RSA_size(myself->rsa_key);
+
+  /* Check if the length of the meta key is all right */
+
+  if(strlen(buffer) != len*2)
+    {
+      syslog(LOG_ERR, _("Intruder: wrong meta key length from %s (%s)"), cl->name, cl->hostname);
+      free(buffer);
+      return -1;
+    }
+
+  /* Allocate buffers for the meta key */
+
+  if(!cl->cipher_inkey)
+    cl->cipher_inkey = xmalloc(len);
+
+  if(!cl->cipher_inctx)
+    cl->cipher_inctx = xmalloc(sizeof(*cl->cipher_inctx));
+
+  /* Convert the challenge from hexadecimal back to binary */
+
+  hex2bin(buffer,buffer,len);
+
+  /* Decrypt the meta key */
+  
+  if(RSA_private_decrypt(len, buffer, cl->cipher_inkey, myself->rsa_key, RSA_NO_PADDING) != len)	/* See challenge() */
+    {
+      syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), cl->name, cl->hostname);
+      free(buffer);
+      return -1;
+    }
+
+  if(debug_lvl >= DEBUG_SCARY_THINGS)
+    {
+      bin2hex(cl->cipher_inkey, buffer, len);
+      buffer[len*2] = '\0';
+      syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
+    }
+
+  free(buffer);
+
+  EVP_DecryptInit(cl->cipher_inctx, EVP_bf_cfb(), cl->cipher_inkey, cl->cipher_inkey + EVP_bf_cfb()->key_len);
+  
+cp
+  if(cl->status.outgoing)
+    return send_ack(cl);
+  else
+    return send_metakey(cl);
+}
+
 int send_ack(conn_list_t *cl)
 {
+  int x;
 cp
-  cl->allow_request = ACK;
+  if(cl->status.outgoing)
+    cl->allow_request = ACK;
+
+  x = send_request(cl, "%d", ACK);
+  cl->status.encryptout = 1;
 cp
-  return send_request(cl, "%d", ACK);
+  return x;
 }
 
 int ack_h(conn_list_t *cl)
@@ -452,21 +582,18 @@ cp
       if(debug_lvl >= DEBUG_CONNECTIONS)
         syslog(LOG_NOTICE, _("Removing old entry for %s at %s in favour of new connection from %s"),
         cl->name, old->hostname, cl->hostname);
-      old->status.active = 0;
+
       terminate_connection(old);
     }
 
-  /* Notify others of this connection */
-  
-  for(p = conn_list; p; p = p->next)
-    if(p->status.active)
-      send_add_host(p, cl);
-
   /* Activate this connection */
 
   cl->allow_request = ALL;
   cl->status.active = 1;
+  cl->status.decryptin = 1;
   cl->nexthop = cl;
+  cl->cipher_pkttype = EVP_bf_cfb();
+  cl->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len;
 
   if(debug_lvl >= DEBUG_CONNECTIONS)
     syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname);
@@ -479,6 +606,24 @@ cp
   
   for(s = myself->subnets; s; s = s->next)
     send_add_subnet(cl, s);
+
+  /* And send him all the hosts and their subnets we know... */
+  
+  for(p = conn_list; p; p = p->next)
+    if(p != cl && p->status.active)
+      {
+        /* Notify others of this connection */
+  
+        if(p->status.meta)
+          send_add_host(p, cl);
+
+        /* Notify new connection of everything we know */
+
+        send_add_host(cl, p);
+        
+        for(s = p->subnets; s; s = s->next)
+          send_add_subnet(cl, s);
+      }
 cp
   return 0;
 }
@@ -501,8 +646,8 @@ int add_subnet_h(conn_list_t *cl)
 {
   char *subnetstr;
   char *name;
-  conn_list_t *owner;
-  subnet_t *subnet, *old;
+  conn_list_t *owner, *p;
+  subnet_t *subnet;
 cp
   if(sscanf(cl->buffer, "%*d %as %as", &name, &subnetstr) != 2)
     {
@@ -555,6 +700,12 @@ cp
   /* If everything is correct, add the subnet to the list of the owner */
 
   subnet_add(owner, subnet);
+
+  /* Tell the rest */
+  
+  for(p = conn_list; p; p = p->next)
+    if(p->status.meta && p->status.active && p!= cl)
+      send_add_subnet(p, subnet);
 cp
   return 0;
 }
@@ -575,8 +726,8 @@ int del_subnet_h(conn_list_t *cl)
 {
   char *subnetstr;
   char *name;
-  conn_list_t *owner;
-  subnet_t *subnet, *old;
+  conn_list_t *owner, *p;
+  subnet_t *subnet;
 cp
   if(sscanf(cl->buffer, "%*d %as %as", &name, &subnetstr) != 3)
     {
@@ -629,6 +780,12 @@ cp
   /* If everything is correct, delete the subnet from the list of the owner */
 
   subnet_del(subnet);
+
+  /* Tell the rest */
+  
+  for(p = conn_list; p; p = p->next)
+    if(p->status.meta && p->status.active && p!= cl)
+      send_del_subnet(p, subnet);
 cp
   return 0;
 }
@@ -638,18 +795,19 @@ cp
 int send_add_host(conn_list_t *cl, conn_list_t *other)
 {
 cp
-  return send_request(cl, "%d %s %s %lx:%d %lx", ADD_HOST,
-                      myself->name, other->name, other->address, other->port, other->options);
+  return send_request(cl, "%d %s %lx:%d %lx", ADD_HOST,
+                      other->name, other->address, other->port, other->options);
 }
 
 int add_host_h(conn_list_t *cl)
 {
-  char *sender;
-  conn_list_t *old, *new, *hisuplink;
+  conn_list_t *old, *new;
+  conn_list_t *p;
+
 cp
   new = new_conn_list();
 
-  if(sscanf(cl->buffer, "%*d %as %as %lx:%d %lx", &sender, &new->name, &new->address, &new->port, &new->options) != 5)
+  if(sscanf(cl->buffer, "%*d %as %lx:%d %lx", &new->name, &new->address, &new->port, &new->options) != 4)
     {
        syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s)"), cl->name, cl->hostname);
        return -1;
@@ -657,10 +815,10 @@ cp
 
   /* Check if identity is a valid name */
 
-  if(check_id(new->name) || check_id(sender))
+  if(check_id(new->name))
     {
       syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid identity name"), cl->name, cl->hostname);
-      free(sender);
+      free_conn_list(new);
       return -1;
     }
 
@@ -670,32 +828,10 @@ cp
     {
       syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) for ourself, restarting"), cl->name, cl->hostname);
       sighup = 1;
-      free(sender);
+      free_conn_list(new);
       return 0;
     }
-
-  /* We got an ADD_HOST from ourself!? */
-
-  if(!strcmp(sender, myself->name))
-    {
-      syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) from ourself, restarting"), cl->name, cl->hostname);
-      sighup = 1;
-      free(sender);
-      return 0;
-    }
-
-  /* Lookup his uplink */
-
-  if(!(new->hisuplink = lookup_id(sender)))
-    {
-      syslog(LOG_ERR, _("Got ADD_HOST from %s (%s) with origin %s which is not in our connection list"),
-             sender, cl->name, cl->hostname);
-      free(sender);
-      return -1;
-    }
     
-  free(sender);
-
   /* Fill in more of the new conn_list structure */
 
   new->hostname = hostlookup(htonl(new->address));
@@ -709,31 +845,34 @@ cp
           if(debug_lvl >= DEBUG_CONNECTIONS)
             syslog(LOG_NOTICE, _("Got duplicate ADD_HOST for %s (%s) from %s (%s)"),
                    old->name, old->hostname, new->name, new->hostname);
+          free_conn_list(new);
           return 0;
         }
       else
         {
           if(debug_lvl >= DEBUG_CONNECTIONS)
-            syslog(LOG_NOTICE, _("Removing old entry for %s (%s)"),
+            syslog(LOG_NOTICE, _("Removing old entry for %s (%s) in favour of new connection"),
                    old->name, old->hostname);
-          old->status.active = 0;
+
           terminate_connection(old);
         }
     }
 
+  /* Hook it up into the conn_list */
+
+  conn_list_add(new);
+
+  /* Tell the rest about the new host */
+
+  for(p = conn_list; p; p = p->next)
+    if(p->status.meta && p->status.active && p!=cl)
+      send_add_host(p, new);
+
   /* Fill in rest of conn_list structure */
 
   new->nexthop = cl;
   new->status.active = 1;
 
-  /* Hook it up into the conn_list */
-
-  conn_list_add(conn_list, new);
-
-  /* Tell the rest about the new host */
-/* FIXME: reprogram this.
-  notify_others(new, cl, send_add_host);
-*/
 cp
   return 0;
 }
@@ -741,21 +880,19 @@ cp
 int send_del_host(conn_list_t *cl, conn_list_t *other)
 {
 cp
-  return send_request(cl, "%d %s %s %lx:%d %lx", DEL_HOST,
-                      myself->name, other->name, other->address, other->port, other->options);
+  return send_request(cl, "%d %s %lx:%d %lx", DEL_HOST,
+                      other->name, other->address, other->port, other->options);
 }
 
 int del_host_h(conn_list_t *cl)
 {
   char *name;
-  char *sender;
   ip_t address;
   port_t port;
-  int options;
-  conn_list_t *old, *hisuplink;
-
+  long int options;
+  conn_list_t *old, *p;
 cp
-  if(sscanf(cl->buffer, "%*d %as %as %lx:%d %lx", &sender, &name, &address, &port, &options) != 5)
+  if(sscanf(cl->buffer, "%*d %as %lx:%d %lx", &name, &address, &port, &options) != 4)
     {
       syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s)"),
              cl->name, cl->hostname);
@@ -764,10 +901,10 @@ cp
 
   /* Check if identity is a valid name */
 
-  if(check_id(name) || check_id(sender))
+  if(check_id(name))
     {
       syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s): invalid identity name"), cl->name, cl->hostname);
-      free(name); free(sender);
+      free(name);
       return -1;
     }
 
@@ -777,33 +914,11 @@ cp
     {
       syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) for ourself, restarting"),
              cl->name, cl->hostname);
-      free(name); free(sender);
-      sighup = 1;
-      return 0;
-    }
-
-  /* We got an ADD_HOST from ourself!? */
-
-  if(!strcmp(sender, myself->name))
-    {
-      syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) from ourself, restarting"), cl->name, cl->hostname);
+      free(name);
       sighup = 1;
-      free(name); free(sender);
       return 0;
     }
 
-  /* Lookup his uplink */
-
-  if(!(hisuplink = lookup_id(sender)))
-    {
-      syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) with origin %s which is not in our connection list"),
-             cl->name, cl->hostname, sender);
-      free(name); free(sender);
-      return -1;
-    }
-    
-  free(sender);
-
   /* Check if the new host already exists in the connnection list */
 
   if(!(old = lookup_id(name)))
@@ -816,7 +931,7 @@ cp
   
   /* Check if the rest matches */
   
-  if(address!=old->address || port!=old->port || options!=old->options || hisuplink!=old->hisuplink || cl!=old->myuplink)
+  if(address!=old->address || port!=old->port || options!=old->options || cl!=old->nexthop)
     {
       syslog(LOG_WARNING, _("Got DEL_HOST from %s (%s) for %s which doesn't match"), cl->name, cl->hostname, old->name);
       return 0;
@@ -824,10 +939,14 @@ cp
 
   /* Ok, since EVERYTHING seems to check out all right, delete it */
 
-  old->status.termreq = 1;
   old->status.active = 0;
-
   terminate_connection(old);
+
+  /* Tell the rest about the new host */
+
+  for(p = conn_list; p; p = p->next)
+    if(p->status.meta && p->status.active && p!=cl)
+      send_del_host(p, old);
 cp
   return 0;
 }
@@ -893,7 +1012,6 @@ cp
     }
 
   free(errorstring);
-  cl->status.termreq = 1;
   terminate_connection(cl);
 cp
   return 0;
@@ -908,7 +1026,6 @@ cp
 int termreq_h(conn_list_t *cl)
 {
 cp
-  cl->status.termreq = 1;
   terminate_connection(cl);
 cp
   return 0;
@@ -1000,6 +1117,7 @@ int req_key_h(conn_list_t *cl)
 {
   char *from_id, *to_id;
   conn_list_t *from, *to;
+  char pktkey[129];
 cp
   if(sscanf(cl->buffer, "%*d %as %as", &from_id, &to_id) != 2)
     {
@@ -1020,7 +1138,9 @@ cp
 
   if(!strcmp(to_id, myself->name))
     {
-      send_ans_key(myself, from, myself->cipher_pktkey);
+      bin2hex(myself->cipher_pktkey, pktkey, myself->cipher_pktkeylength);
+      pktkey[myself->cipher_pktkeylength*2] = '\0';
+      send_ans_key(myself, from, pktkey);
     }
   else
     {
@@ -1031,7 +1151,15 @@ cp
           free(from_id); free(to_id);
           return -1;
         }
-      send_req_key(from, to);
+        
+      if(to->status.validkey)	/* Proxy keys */
+        {
+          bin2hex(to->cipher_pktkey, pktkey, to->cipher_pktkeylength);
+          pktkey[to->cipher_pktkeylength*2] = '\0';
+          send_ans_key(to, from, pktkey);
+        }
+      else
+        send_req_key(from, to);
     }
 
   free(from_id); free(to_id);
@@ -1067,43 +1195,42 @@ cp
       return -1;
     }
 
-  /* Check if this key request is for us */
+  /* Update origin's packet key */
 
-  if(!strcmp(to_id, myself->name))
+  keylength = strlen(pktkey);
+
+  if(keylength != from->cipher_pktkeylength*2)
     {
-      /* It is for us, convert it to binary and set the key with it. */
+      syslog(LOG_ERR, _("Got bad ANS_KEY from %s (%s) origin %s: invalid key length"),
+             cl->name, cl->hostname, from->name);
+      free(from_id); free(to_id); free(pktkey);
+      return -1;
+    }
 
-      keylength = strlen(pktkey);
+  if(from->cipher_pktkey)
+    free(from->cipher_pktkey);
 
-/* Don't do this... yet
-      if((keylength%2) || (keylength <= 0))
-        {
-          syslog(LOG_ERR, _("Got bad ANS_KEY from %s (%s) origin %s: invalid key"),
-                 cl->name, cl->hostname, from->name);
-          free(from_id); free(to_id); free(pktkey);
-          return -1;
-        }
-      keylength /= 2;
-      hex2bin(pktkey, pktkey, keylength);
-      BF_set_key(cl->cipher_pktkey, keylength, pktkey);
-*/
+  keylength /= 2;
+  hex2bin(pktkey, pktkey, keylength);
+  pktkey[keylength] = '\0';
+  from->cipher_pktkey = pktkey;
 
-      cl->status.validkey = 1;
-      cl->status.waitingforkey = 0;
-    }
-  else
+  from->status.validkey = 1;
+  from->status.waitingforkey = 0;
+    
+  if(strcmp(to_id, myself->name))
     {
       if(!(to = lookup_id(to_id)))
         {
           syslog(LOG_ERR, _("Got ANS_KEY from %s (%s) destination %s which does not exist in our connection list"),
                  cl->name, cl->hostname, to_id);
-          free(from_id); free(to_id); free(pktkey);
+          free(from_id); free(to_id);
           return -1;
         }
       send_ans_key(from, to, pktkey);
     }
 
-  free(from_id); free(to_id); free(pktkey);
+  free(from_id); free(to_id);
 cp
   return 0;
 }
@@ -1111,7 +1238,7 @@ cp
 /* Jumptable for the request handlers */
 
 int (*request_handlers[])(conn_list_t*) = {
-  id_h, challenge_h, chal_reply_h, ack_h,
+  id_h, challenge_h, chal_reply_h, metakey_h, ack_h,
   status_h, error_h, termreq_h,
   ping_h, pong_h,
   add_host_h, del_host_h,
@@ -1122,7 +1249,7 @@ int (*request_handlers[])(conn_list_t*) = {
 /* Request names */
 
 char (*request_name[]) = {
-  "ID", "CHALLENGE", "CHAL_REPLY", "ACK",
+  "ID", "CHALLENGE", "CHAL_REPLY", "METAKEY", "ACK",
   "STATUS", "ERROR", "TERMREQ",
   "PING", "PONG",
   "ADD_HOST", "DEL_HOST",