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- Finishing touch: encrypt the meta connections

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This commit is contained in:
Guus Sliepen 2000-10-29 22:55:15 +00:00
parent ec12269355
commit b7d4d4c177
5 changed files with 152 additions and 28 deletions
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4
src/connlist.h
View file

@ -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: connlist.h,v 1.1.2.8 2000/10/29 22:10:41 guus Exp $
$Id: connlist.h,v 1.1.2.9 2000/10/29 22:55:14 guus Exp $
*/
#ifndef __TINC_CONNLIST_H__
@ -69,6 +69,8 @@ typedef struct conn_list_t {
EVP_CIPHER_CTX *cipher_inctx; /* Context of encrypted meta data that will come from him to us */
EVP_CIPHER_CTX *cipher_outctx; /* Context of encrypted meta data that will be sent from us to him */
char *cipher_inkey; /* His symmetric meta key */
char *cipher_outkey; /* Our symmetric meta key */
EVP_CIPHER *cipher_pkttype; /* Cipher type for encrypted vpn packets */
char *cipher_pktkey; /* Cipher key and iv */

15
src/meta.c
View file

@ -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: meta.c,v 1.1.2.7 2000/10/29 00:02:18 guus Exp $
$Id: meta.c,v 1.1.2.8 2000/10/29 22:55:14 guus Exp $
*/
#include "config.h"
@ -46,14 +46,14 @@ cp
cl->name, cl->hostname, buffer);
buffer[length-1]='\n';
/*
if(cl->status.encryptout)
{
EVP_EncryptUpdate(cl->cipher_outctx, outbuf, &outlen, buffer, length);
bufp = outbuf;
length = outlen;
}
else
*/
bufp = buffer;
if(write(cl->meta_socket, bufp, length) < 0)
@ -96,11 +96,10 @@ cp
cl->name, cl->hostname, strerror(x));
return -1;
}
/*
if(cl->status.decryptin)
bufp = inbuf;
else
*/
bufp = cl->buffer + cl->buflen;
lenin = read(cl->meta_socket, bufp, MAXBUFSIZE - cl->buflen);
@ -120,12 +119,12 @@ cp
cl->name, cl->hostname);
return -1;
}
/*
if(cl->status.decryptin)
{
EVP_DecryptUpdate(cl->cipher_inctx, cl->buffer + cl->buflen, NULL, inbuf, lenin);
EVP_DecryptUpdate(cl->cipher_inctx, cl->buffer + cl->buflen, &lenin, inbuf, lenin);
}
*/
oldlen = cl->buflen;
cl->buflen += lenin;

145
src/protocol.c
View file

@ -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 1.28.4.52 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"
@ -145,8 +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)
@ -256,10 +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);
@ -374,7 +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);
@ -433,18 +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
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)
@ -470,6 +590,7 @@ cp
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;
@ -1116,7 +1237,7 @@ 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,
@ -1127,7 +1248,7 @@ 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",

5
src/protocol.h
View file

@ -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.h,v 1.5.4.13 2000/10/28 21:05:20 guus Exp $
$Id: protocol.h,v 1.5.4.14 2000/10/29 22:55:15 guus Exp $
*/
#ifndef __TINC_PROTOCOL_H__
@ -36,7 +36,7 @@
enum {
ALL = -1, /* Guardian for allow_request */
ID = 0, CHALLENGE, CHAL_REPLY, ACK,
ID = 0, CHALLENGE, CHAL_REPLY, METAKEY, ACK,
STATUS, ERROR, TERMREQ,
PING, PONG,
ADD_HOST, DEL_HOST,
@ -50,6 +50,7 @@ extern int (*request_handlers[])(conn_list_t*);
extern int send_id(conn_list_t*);
extern int send_challenge(conn_list_t*);
extern int send_chal_reply(conn_list_t*);
extern int send_metakey(conn_list_t*);
extern int send_ack(conn_list_t*);
extern int send_status(conn_list_t*, int, char*);
extern int send_error(conn_list_t*, int, char*);

9
src/tincd.c
View file

@ -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: tincd.c,v 1.10.4.20 2000/10/29 22:10:44 guus Exp $
$Id: tincd.c,v 1.10.4.21 2000/10/29 22:55:15 guus Exp $
*/
#include "config.h"
@ -205,9 +205,6 @@ int keygen(int bits)
{
RSA *rsa_key;
fprintf(stderr, _("Seeding the PRNG: please press some keys or move\nthe mouse if this program seems to have halted...\n"));
RAND_load_file("/dev/random", 1024); /* OpenSSL PRNG state apparently uses 1024 bytes, but it seems pretty sufficient anyway :) */
fprintf(stderr, _("Generating %d bits keys:\n"), bits);
rsa_key = RSA_generate_key(bits, 0xFFFF, indicator, NULL);
if(!rsa_key)
@ -423,6 +420,10 @@ main(int argc, char **argv, char **envp)
make_names();
/* Slllluuuuuuurrrrp! */
RAND_load_file("/dev/urandom", 1024);
if(generate_keys)
exit(keygen(generate_keys));