along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- $Id: protocol.c,v 1.28.4.52 2000/10/29 22:10:43 guus Exp $
+ $Id: protocol.c,v 1.28.4.53 2000/10/29 22:55:14 guus Exp $
*/
#include "config.h"
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)
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);
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);
*/
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
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)
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;
/* 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,
/* 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",
projects / tinc / blobdiff