From b7d4d4c17712e0bb9ee8bd497a2f525b79d5f40d Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Sun, 29 Oct 2000 22:55:15 +0000 Subject: [PATCH] - Finishing touch: encrypt the meta connections --- src/connlist.h | 4 +- src/meta.c | 17 +++--- src/protocol.c | 145 +++++++++++++++++++++++++++++++++++++++++++++---- src/protocol.h | 5 +- src/tincd.c | 9 +-- 5 files changed, 152 insertions(+), 28 deletions(-) diff --git a/src/connlist.h b/src/connlist.h index d993c840..69bef9ee 100644 --- a/src/connlist.h +++ b/src/connlist.h @@ -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 */ diff --git a/src/meta.c b/src/meta.c index 5774bb93..6b2a8e2b 100644 --- a/src/meta.c +++ b/src/meta.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: 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" @@ -46,15 +46,15 @@ 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; + 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; diff --git a/src/protocol.c b/src/protocol.c index d3b34c98..40acfbb2 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 1.28.4.52 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", diff --git a/src/protocol.h b/src/protocol.h index 682f76a0..91c0cfba 100644 --- a/src/protocol.h +++ b/src/protocol.h @@ -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*); diff --git a/src/tincd.c b/src/tincd.c index 2e607b67..ba17b30f 100644 --- a/src/tincd.c +++ b/src/tincd.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: 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)); -- 2.39.5