X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fprotocol.c;h=31c9aeeb2756597e1da68c9fd7a703e12b3a205f;hp=1bb37346318535acdb46ce44196e13ba97f604f3;hb=3f8f067e8b559366b9b41dee6a4312702c82042f;hpb=7398002ade1397bd857953f009f4aed65ffc9218 diff --git a/src/protocol.c b/src/protocol.c index 1bb37346..31c9aeeb 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 1.28.4.48 2000/10/29 00:24:31 guus Exp $ + $Id: protocol.c,v 1.28.4.55 2000/11/04 16:39:19 guus Exp $ */ #include "config.h" @@ -38,9 +38,9 @@ #include #include +#include #include "conf.h" -#include "encr.h" #include "net.h" #include "netutl.h" #include "protocol.h" @@ -111,6 +111,12 @@ cp 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. */ { @@ -139,8 +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) @@ -168,7 +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) { @@ -250,10 +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); @@ -368,7 +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); @@ -427,17 +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) @@ -463,7 +590,10 @@ 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; if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname); @@ -673,6 +803,7 @@ int add_host_h(conn_list_t *cl) { conn_list_t *old, *new; conn_list_t *p; + cp new = new_conn_list(); @@ -741,6 +872,8 @@ cp new->nexthop = cl; new->status.active = 1; + new->cipher_pkttype = EVP_bf_cfb(); + new->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len; cp return 0; @@ -986,6 +1119,7 @@ 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) { @@ -1006,7 +1140,9 @@ 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 { @@ -1017,7 +1153,15 @@ 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); @@ -1053,43 +1197,42 @@ 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; - from->status.validkey = 1; - from->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; } @@ -1097,7 +1240,7 @@ 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, @@ -1108,7 +1251,7 @@ 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",