along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- $Id: protocol.c,v 1.28.4.83 2001/02/27 16:37:28 guus Exp $
+ $Id: protocol.c,v 1.28.4.95 2001/06/29 13:09:32 guus Exp $
*/
#include "config.h"
#include "system.h"
+int mykeyused = 0;
+
int check_id(char *id)
{
int i;
return -1;
}
- len++;
-
if(debug_lvl >= DEBUG_PROTOCOL)
- syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname);
+ {
+ if(debug_lvl >= DEBUG_META)
+ syslog(LOG_DEBUG, _("Sending %s to %s (%s): %s"), request_name[request], cl->name, cl->hostname, buffer);
+ else
+ syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname);
+ }
+ buffer[len++] = '\n';
cp
return send_meta(cl, buffer, len);
}
int receive_request(connection_t *cl)
{
int request;
-cp
+cp
if(sscanf(cl->buffer, "%d", &request) == 1)
{
- if((request < 0) || (request > 255) || (request_handlers[request] == NULL))
+ if((request < 0) || (request >= LAST) || (request_handlers[request] == NULL))
{
- syslog(LOG_ERR, _("Unknown request from %s (%s)"),
- cl->name, cl->hostname);
+ if(debug_lvl >= DEBUG_META)
+ syslog(LOG_DEBUG, _("Unknown request from %s (%s): %s"),
+ cl->name, cl->hostname, cl->buffer);
+ else
+ syslog(LOG_ERR, _("Unknown request from %s (%s)"),
+ cl->name, cl->hostname);
+
return -1;
}
else
{
if(debug_lvl >= DEBUG_PROTOCOL)
- syslog(LOG_DEBUG, _("Got %s from %s (%s)"),
- request_name[request], cl->name, cl->hostname);
+ {
+ if(debug_lvl >= DEBUG_META)
+ syslog(LOG_DEBUG, _("Got %s from %s (%s): %s"),
+ request_name[request], cl->name, cl->hostname, cl->buffer);
+ else
+ syslog(LOG_DEBUG, _("Got %s from %s (%s)"),
+ request_name[request], cl->name, cl->hostname);
+ }
}
if((cl->allow_request != ALL) && (cl->allow_request != request))
return 0;
}
-/* Connection protocol:
-
- Client Server
- send_id(u)
- send_challenge(R)
- send_chal_reply(H)
- send_id(u)
- send_challenge(R)
- send_chal_reply(H)
- ---------------------------------------
- send_metakey(R)
- send_metakey(R)
- ---------------------------------------
- send_ack(u)
- send_ack(u)
- ---------------------------------------
- Other requests(E)...
-
- (u) Unencrypted,
- (R) RSA,
- (H) SHA1,
- (E) Encrypted with symmetric cipher.
-
- Part of the challenge is directly used to set the symmetric cipher
- key and the initial vector. Since a man-in-the-middle cannot
- decrypt the RSA challenges, this means that he cannot get or forge
- the key for the symmetric cipher.
-*/
+/* The authentication protocol is described in detail in doc/SECURITY2,
+ the rest will be described in doc/PROTOCOL. */
int send_id(connection_t *cl)
{
/* Copy string to cl */
+ if(cl->name)
+ free(cl->name);
+
cl->name = xstrdup(name);
/* Load information about peer */
node = avl_unlink(connection_tree, cl);
cl->port = port;
- avl_insert_node(connection_tree, node);
-
+ if(!avl_insert_node(connection_tree, node))
+ {
+ old = avl_search_node(connection_tree, node)->data;
+ syslog(LOG_ERR, _("%s is listening on %s:%s, which is already in use by %s!"),
+ cl->name, cl->hostname, cl->port, old->name);
+ return -1;
+ }
+
/* Read in the public key, so that we can send a metakey */
if(read_rsa_public_key(cl))
if(debug_lvl >= DEBUG_CONNECTIONS)
syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname);
+ if(cl->status.outgoing)
+ seconds_till_retry = 5; /* Reset retry timeout */
cp
/* Check some options */
subnet = (subnet_t *)node->data;
send_add_subnet(cl, subnet);
}
+
/* And send him all the hosts and their subnets we know... */
for(node = connection_tree->head; node; node = node->next)
RAND_bytes(cl->cipher_outkey, len);
- cl->cipher_outkey[0] &= 0x0F; /* Make sure that the random data is smaller than the modulus of the RSA key */
+ /* The message we send must be smaller than the modulus of the RSA key.
+ By definition, for a key of k bits, the following formula holds:
+
+ 2^(k-1) <= modulus < 2^(k)
+
+ Where ^ means "to the power of", not "xor".
+ This means that to be sure, we must choose our message < 2^(k-1).
+ This can be done by setting the most significant bit to zero.
+ */
+
+ cl->cipher_outkey[0] &= 0x7F;
if(debug_lvl >= DEBUG_SCARY_THINGS)
{
syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
}
- /* Encrypt the random data */
+ /* 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 */
+ We do not use one of the PKCS padding schemes here.
+ This is allowed, because we encrypt a totally random string
+ with a length equal to that of the modulus of the RSA key.
+ */
+
+ if(RSA_public_encrypt(len, cl->cipher_outkey, buffer, cl->rsa_key, RSA_NO_PADDING) != len)
{
syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), cl->name, cl->hostname);
free(buffer);
char *netstr;
char *owner;
cp
- if(cl->options & OPTION_INDIRECT)
+ if((cl->options | myself->options | subnet->owner->options) & OPTION_INDIRECT)
owner = myself->name;
else
owner = subnet->owner->name;
int send_add_host(connection_t *cl, connection_t *other)
{
cp
- if(!(cl->options & OPTION_INDIRECT))
+ if(!((cl->options | myself->options | other->options) & OPTION_INDIRECT))
return send_request(cl, "%d %s %lx:%d %lx", ADD_HOST,
other->name, other->address, other->port, other->options);
else
int send_del_host(connection_t *cl, connection_t *other)
{
cp
- if(!(cl->options & OPTION_INDIRECT))
+ if(!((cl->options | myself->options) & OPTION_INDIRECT))
return send_request(cl, "%d %s %lx:%d %lx", DEL_HOST,
other->name, other->address, other->port, other->options);
else
int del_host_h(connection_t *cl)
{
char name[MAX_STRING_SIZE];
- ip_t address;
+ ipv4_t address;
port_t port;
long int options;
connection_t *old, *p;
int send_ping(connection_t *cl)
{
+ char salt[SALTLEN*2+1];
cp
cl->status.pinged = 1;
cl->last_ping_time = time(NULL);
+ RAND_bytes(salt, SALTLEN);
+ bin2hex(salt, salt, SALTLEN);
+ salt[SALTLEN*2] = '\0';
cp
- return send_request(cl, "%d", PING);
+ return send_request(cl, "%d %s", PING, salt);
}
int ping_h(connection_t *cl)
int send_pong(connection_t *cl)
{
+ char salt[SALTLEN*2+1];
+cp
+ RAND_bytes(salt, SALTLEN);
+ bin2hex(salt, salt, SALTLEN);
+ salt[SALTLEN*2] = '\0';
cp
- return send_request(cl, "%d", PONG);
+ return send_request(cl, "%d %s", PONG, salt);
}
int pong_h(connection_t *cl)
connection_t *p;
avl_node_t *node;
cp
+ /* Only send this message if some other daemon requested our key previously.
+ This reduces unnecessary key_changed broadcasts.
+ */
+
+ if(from==myself && !mykeyused)
+ return 0;
+
for(node = connection_tree->head; node; node = node->next)
{
p = (connection_t *)node->data;
from->status.validkey = 0;
from->status.waitingforkey = 0;
- send_key_changed(from, cl);
+ if(!(from->options | cl->options | myself->options) & OPTION_INDIRECT)
+ send_key_changed(from, cl);
cp
return 0;
}
/* Check if this key request is for us */
- if(!strcmp(to_id, myself->name))
+ if(!strcmp(to_id, myself->name)) /* Yes, send our own key back */
{
bin2hex(myself->cipher_pktkey, pktkey, myself->cipher_pktkeylength);
pktkey[myself->cipher_pktkeylength*2] = '\0';
send_ans_key(myself, from, pktkey);
+ mykeyused = 1;
}
else
{
int send_tcppacket(connection_t *cl, vpn_packet_t *packet)
{
int x;
-
+cp
+ /* Evil hack. */
+
x = send_request(cl->nexthop, "%d %hd", PACKET, packet->len);
if(x)
return x;
-
- return send_meta(cl->nexthop, packet->data, packet->len);
+cp
+ return send_meta(cl, packet->data, packet->len);
}
int tcppacket_h(connection_t *cl)
{
- vpn_packet_t packet;
- char *p;
- int todo, x;
-
- if(sscanf(cl->buffer, "%*d %hd", packet.len) != 1)
+ short int len;
+cp
+ if(sscanf(cl->buffer, "%*d %hd", &len) != 1)
{
syslog(LOG_ERR, _("Got bad PACKET from %s (%s)"), cl->name, cl->hostname);
return -1;
}
- /* Evil hack. */
+ /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */
- p = packet.data;
- todo = packet.len;
-
- while(todo)
- {
- x = read(cl->meta_socket, p, todo);
-
- if(x<=0)
- {
- if(x==0)
- syslog(LOG_NOTICE, _("Connection closed by %s (%s)"), cl->name, cl->hostname);
- else
- if(errno==EINTR)
- continue;
- else
- syslog(LOG_ERR, _("Error during reception of PACKET from %s (%s): %m"), cl->name, cl->hostname);
-
- return -1;
- }
-
- todo -= x;
- p += x;
- }
-
- return receive_packet(cl, &packet);
+ cl->tcplen = len;
+cp
+ return 0;
}
/* Jumptable for the request handlers */
projects / tinc / blobdiff