along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- $Id: protocol.c,v 1.28.4.79 2001/02/25 11:09:29 guus Exp $
+ $Id: protocol.c,v 1.28.4.86 2001/03/13 21:33:31 guus Exp $
*/
#include "config.h"
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);
int send_id(connection_t *cl)
{
-cp
- cl->allow_request = CHALLENGE;
cp
return send_request(cl, "%d %s %d %lx %hd", ID, myself->name, myself->protocol_version, myself->options, myself->port);
}
cl->port = port;
avl_insert_node(connection_tree, node);
- /* Read in the public key, so that we can send a challenge */
+ /* Read in the public key, so that we can send a metakey */
if(read_rsa_public_key(cl))
return -1;
+ cl->allow_request = METAKEY;
cp
- return send_challenge(cl);
+ return send_metakey(cl);
+}
+
+int ack_h(connection_t *cl)
+{
+ config_t const *cfg;
+ connection_t *old, *p;
+ subnet_t *subnet;
+ avl_node_t *node, *node2;
+cp
+ /* Okay, before we active the connection, we check if there is another entry
+ in the connection list with the same name. If so, it presumably is an
+ old connection that has timed out but we don't know it yet.
+ */
+
+ while((old = lookup_id(cl->name)))
+ {
+ 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);
+
+ terminate_connection(old);
+ }
+
+ /* Activate this connection */
+
+ cl->allow_request = ALL;
+ cl->status.active = 1;
+ cl->nexthop = cl;
+ cl->cipher_pkttype = EVP_bf_cbc();
+ 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);
+
+cp
+ /* Check some options */
+
+ if((cfg = get_config_val(cl->config, config_indirectdata)))
+ {
+ if(cfg->data.val == stupid_true)
+ cl->options |= OPTION_INDIRECT;
+ }
+
+ if((cfg = get_config_val(cl->config, config_tcponly)))
+ {
+ if(cfg->data.val == stupid_true)
+ cl->options |= OPTION_TCPONLY;
+ }
+
+ /* Send him our subnets */
+
+ for(node = myself->subnet_tree->head; node; node = node->next)
+ {
+ 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)
+ {
+ p = (connection_t *)node->data;
+
+ 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(node2 = p->subnet_tree->head; node2; node2 = node2->next)
+ {
+ subnet = (subnet_t *)node2->data;
+ send_add_subnet(cl, subnet);
+ }
+ }
+ }
+cp
+ return 0;
}
int send_challenge(connection_t *cl)
char *buffer;
int len, x;
cp
+ /* CHECKME: what is most reasonable value for len? */
+
len = RSA_size(cl->rsa_key);
/* Allocate buffers for the challenge */
RAND_bytes(cl->hischallenge, len);
- cl->hischallenge[0] &= 0x7F; /* Somehow if the first byte is more than 0xD0 or something like that, decryption fails... */
cp
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- {
- bin2hex(cl->hischallenge, buffer, len);
- buffer[len*2] = '\0';
- syslog(LOG_DEBUG, _("Generated random challenge (unencrypted): %s"), buffer);
- }
+ /* Convert to hex */
- /* Encrypt the random data */
-
- if(RSA_public_encrypt(len, cl->hischallenge, 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 challenge 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);
+ bin2hex(cl->hischallenge, buffer, len);
buffer[len*2] = '\0';
+
cp
/* Send the challenge */
- cl->allow_request = CHAL_REPLY;
x = send_request(cl, "%d %s", CHALLENGE, buffer);
free(buffer);
cp
/* Convert the challenge from hexadecimal back to binary */
- hex2bin(buffer,buffer,len);
+ hex2bin(buffer,cl->mychallenge,len);
- /* Decrypt the challenge */
-
- if(RSA_private_decrypt(len, buffer, cl->mychallenge, myself->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
- {
- syslog(LOG_ERR, _("Error during encryption of challenge for %s (%s)"), cl->name, cl->hostname);
- return -1;
- }
-
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- {
- bin2hex(cl->mychallenge, buffer, len);
- buffer[len*2] = '\0';
- syslog(LOG_DEBUG, _("Received random challenge (unencrypted): %s"), buffer);
- }
+ cl->allow_request = CHAL_REPLY;
/* Rest is done by send_chal_reply() */
cp
/* Send the reply */
- if(cl->status.outgoing)
- cl->allow_request = ID;
- else
- cl->allow_request = METAKEY;
-
cp
return send_request(cl, "%d %s", CHAL_REPLY, hash);
}
return -1;
}
-
/* Identity has now been positively verified.
- If we are accepting this new connection, then send our identity,
- if we are making this connecting, acknowledge.
+ ack_h() handles the rest from now on.
*/
cp
- if(cl->status.outgoing)
- return send_metakey(cl);
- else
- return send_id(cl);
+ return ack_h(cl);
}
int send_metakey(connection_t *cl)
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... */
-
+ /* 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)
{
bin2hex(cl->cipher_outkey, buffer, len);
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);
/* 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);
+ /* Further outgoing requests are encrypted with the key we just generated */
+
+ EVP_EncryptInit(cl->cipher_outctx, EVP_bf_cfb(),
+ cl->cipher_outkey + len - EVP_bf_cfb()->key_len,
+ cl->cipher_outkey + len - EVP_bf_cfb()->key_len - EVP_bf_cfb()->iv_len);
+
+ cl->status.encryptout = 1;
cp
return x;
}
syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), 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(connection_t *cl)
-{
- int x;
-cp
- if(cl->status.outgoing)
- cl->allow_request = ACK;
-
- x = send_request(cl, "%d", ACK);
- cl->status.encryptout = 1;
-cp
- return x;
-}
-
-int ack_h(connection_t *cl)
-{
- config_t const *cfg;
- connection_t *old, *p;
- subnet_t *subnet;
- avl_node_t *node, *node2;
-cp
- /* Okay, before we active the connection, we check if there is another entry
- in the connection list with the same name. If so, it presumably is an
- old connection that has timed out but we don't know it yet.
- */
-
- while((old = lookup_id(cl->name)))
- {
- 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);
-
- terminate_connection(old);
- }
-
- /* 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);
-
-cp
- if(!cl->status.outgoing)
- send_ack(cl);
-
- /* Check some options */
-
- if((cfg = get_config_val(cl->config, config_indirectdata)))
- {
- if(cfg->data.val == stupid_true)
- cl->options |= OPTION_INDIRECT;
- }
-
- if((cfg = get_config_val(cl->config, config_tcponly)))
- {
- if(cfg->data.val == stupid_true)
- cl->options |= OPTION_TCPONLY;
- }
+ /* All incoming requests will now be encrypted. */
- /* Send him our subnets */
-
- for(node = myself->subnet_tree->head; node; node = node->next)
- {
- subnet = (subnet_t *)node->data;
- send_add_subnet(cl, subnet);
- }
- /* And send him all the hosts and their subnets we know... */
+ EVP_DecryptInit(cl->cipher_inctx, EVP_bf_cfb(),
+ cl->cipher_inkey + len - EVP_bf_cfb()->key_len,
+ cl->cipher_inkey + len - EVP_bf_cfb()->key_len - EVP_bf_cfb()->iv_len);
- for(node = connection_tree->head; node; node = node->next)
- {
- p = (connection_t *)node->data;
-
- 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);
+ cl->status.decryptin = 1;
- for(node2 = p->subnet_tree->head; node2; node2 = node2->next)
- {
- subnet = (subnet_t *)node2->data;
- send_add_subnet(cl, subnet);
- }
- }
- }
+ cl->allow_request = CHALLENGE;
cp
- return 0;
+ return send_challenge(cl);
}
/* Address and subnet information exchange */
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
+ return 0;
}
int add_host_h(connection_t *cl)
cp
new = new_connection();
- if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%d %lx", name, &new->address, &new->port, &new->options) != 4)
+ if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx", name, &new->address, &new->port, &new->options) != 4)
{
syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s)"), cl->name, cl->hostname);
return -1;
new->nexthop = cl;
new->status.active = 1;
- new->cipher_pkttype = EVP_bf_cfb();
+ new->cipher_pkttype = EVP_bf_cbc();
new->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len;
cp
return 0;
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
+ return 0;
}
int del_host_h(connection_t *cl)
connection_t *old, *p;
avl_node_t *node;
cp
- if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%d %lx", name, &address, &port, &options) != 4)
+ if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx", name, &address, &port, &options) != 4)
{
syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s)"),
cl->name, cl->hostname);
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;
}
int send_tcppacket(connection_t *cl, vpn_packet_t *packet)
{
int x;
-
+cp
x = send_request(cl->nexthop, "%d %hd", PACKET, packet->len);
if(x)
vpn_packet_t packet;
char *p;
int todo, x;
-
- if(sscanf(cl->buffer, "%*d %hd", packet.len) != 1)
+cp
+ if(sscanf(cl->buffer, "%*d %hd", &packet.len) != 1)
{
syslog(LOG_ERR, _("Got bad PACKET from %s (%s)"), cl->name, cl->hostname);
return -1;
p = packet.data;
todo = packet.len;
-
+
while(todo)
{
x = read(cl->meta_socket, p, todo);
if(x==0)
syslog(LOG_NOTICE, _("Connection closed by %s (%s)"), cl->name, cl->hostname);
else
- if(errno==EINTR)
+ if(errno==EINTR || errno==EAGAIN) /* FIXME: select() or poll() or reimplement this evil hack */
continue;
else
syslog(LOG_ERR, _("Error during reception of PACKET from %s (%s): %m"), cl->name, cl->hostname);
p += x;
}
- return receive_packet(cl, &packet);
+ receive_packet(cl, &packet);
+cp
+ return 0;
}
/* Jumptable for the request handlers */
int (*request_handlers[])(connection_t*) = {
- id_h, challenge_h, chal_reply_h, metakey_h, ack_h,
+ id_h, metakey_h, challenge_h, chal_reply_h,
status_h, error_h, termreq_h,
ping_h, pong_h,
add_host_h, del_host_h,
/* Request names */
char (*request_name[]) = {
- "ID", "CHALLENGE", "CHAL_REPLY", "METAKEY", "ACK",
+ "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY",
"STATUS", "ERROR", "TERMREQ",
"PING", "PONG",
"ADD_HOST", "DEL_HOST",
projects / tinc / blobdiff