--- gvpe/src/connection.C 2011/03/24 21:52:48 1.96 +++ gvpe/src/connection.C 2013/07/17 16:40:57 1.101 @@ -1,6 +1,6 @@ /* connection.C -- manage a single connection - Copyright (C) 2003-2008,2010,2011 Marc Lehmann + Copyright (C) 2003-2008,2010,2011,2013 Marc Lehmann This file is part of GVPE. @@ -45,15 +45,12 @@ #include "device.h" #include "vpn.h" #include "connection.h" +#include "hkdf.h" #include "netcompat.h" -#if !HAVE_RAND_PSEUDO_BYTES -# define RAND_pseudo_bytes RAND_bytes -#endif - -#define MAGIC_OLD "vped\xbd\xc6\xdb\x82" // 8 bytes of magic (still used in the protocol) -#define MAGIC "gvpe\xbd\xc6\xdb\x82" // 8 bytes of magic (understood but not generated) +#define MAGIC "gvpe\xbd\xc6\xdb\x82" // 8 bytes of magic +#define MAGIC "PORN\xbd\xc6\xdb\x82" // 8 bytes of magic//D #define ULTRA_FAST 1 #define HLOG 15 @@ -110,16 +107,45 @@ EVP_CIPHER_CTX cctx; HMAC_CTX hctx; - crypto_ctx (const rsachallenge &challenge, int enc); + crypto_ctx (const auth_data &auth1, const auth_data &auth2, const ecdh_key &a, const ecdh_key &b, int enc); ~crypto_ctx (); }; -crypto_ctx::crypto_ctx (const rsachallenge &challenge, int enc) +crypto_ctx::crypto_ctx (const auth_data &auth1, const auth_data &auth2, const ecdh_key &a, const ecdh_key &b, int enc) { - EVP_CIPHER_CTX_init (&cctx); - require (EVP_CipherInit_ex (&cctx, CIPHER, 0, &challenge[CHG_CIPHER_KEY], 0, enc)); - HMAC_CTX_init (&hctx); - HMAC_Init_ex (&hctx, &challenge[CHG_HMAC_KEY], HMAC_KEYLEN, DIGEST, 0); + ecdh_key s; + + curve25519_combine (a, b, s); + + { + u8 mac_key[MAC_KEYSIZE]; + static const unsigned char mac_info[] = "gvpe mac key"; + + hkdf kdf (auth2.rsa.hkdf_salt, sizeof (auth2.rsa.hkdf_salt), HKDF_XTR_HASH ()); + kdf.extract (auth2.rsa.ikm, sizeof (auth2.rsa.ikm)); + kdf.extract (auth1.rsa.mac_key, sizeof (auth1.rsa.mac_key)); + kdf.extract (s, sizeof (s)); + kdf.extract_done (HKDF_PRF_HASH ()); + kdf.expand (mac_key, sizeof (mac_key), mac_info, sizeof (mac_info)); + + HMAC_CTX_init (&hctx); + require (HMAC_Init_ex (&hctx, mac_key, MAC_KEYSIZE, MAC_DIGEST (), 0)); + } + + { + u8 cipher_key[CIPHER_KEYSIZE]; + static const unsigned char cipher_info[] = "gvpe cipher key"; + + hkdf kdf (auth2.rsa.hkdf_salt, sizeof (auth2.rsa.hkdf_salt), HKDF_XTR_HASH ()); + kdf.extract (auth2.rsa.ikm, sizeof (auth2.rsa.ikm)); + kdf.extract (auth1.rsa.cipher_key, sizeof (auth1.rsa.cipher_key)); + kdf.extract (s, sizeof (s)); + kdf.extract_done (HKDF_PRF_HASH ()); + kdf.expand (cipher_key, sizeof (cipher_key), cipher_info, sizeof (cipher_info)); + + EVP_CIPHER_CTX_init (&cctx); + require (EVP_CipherInit_ex (&cctx, CIPHER (), 0, cipher_key, 0, enc)); + } } crypto_ctx::~crypto_ctx () @@ -128,87 +154,61 @@ HMAC_CTX_cleanup (&hctx); } -static void -rsa_hash (const rsaid &id, const rsachallenge &chg, rsaresponse &h) +static inline void +auth_encrypt (RSA *key, const auth_data &auth, auth_encr &encr) { - EVP_MD_CTX ctx; + if (RSA_public_encrypt (sizeof (auth.rsa), + (unsigned char *)&auth.rsa, (unsigned char *)&encr.rsa, + key, RSA_PKCS1_OAEP_PADDING) < 0) + fatal ("RSA_public_encrypt error"); - EVP_MD_CTX_init (&ctx); - require (EVP_DigestInit (&ctx, RSA_HASH)); - require (EVP_DigestUpdate (&ctx, &chg, sizeof chg)); - require (EVP_DigestUpdate (&ctx, &id, sizeof id)); - require (EVP_DigestFinal (&ctx, (unsigned char *)&h, 0)); - EVP_MD_CTX_cleanup (&ctx); + memcpy (&encr.ecdh, &auth.ecdh, sizeof (encr.ecdh)); } -struct rsa_entry +static inline bool +auth_decrypt (RSA *key, const auth_encr &encr, auth_data &auth) { - tstamp expire; - rsaid id; - rsachallenge chg; -}; + u8 rsa_decrypt[RSA_KEYLEN]; -struct rsa_cache : list -{ - inline void cleaner_cb (ev::timer &w, int revents); ev::timer cleaner; - - bool find (const rsaid &id, rsachallenge &chg) - { - for (iterator i = begin (); i != end (); ++i) - { - if (!memcmp (&id, &i->id, sizeof id) && i->expire > ev_now ()) - { - memcpy (&chg, &i->chg, sizeof chg); - - erase (i); - return true; - } - } - - if (!cleaner.is_active ()) - cleaner.again (); - - return false; - } - - void gen (rsaid &id, rsachallenge &chg) - { - rsa_entry e; - - RAND_bytes ((unsigned char *)&id, sizeof id); - RAND_bytes ((unsigned char *)&chg, sizeof chg); - - e.expire = ev_now () + RSA_TTL; - e.id = id; - memcpy (&e.chg, &chg, sizeof chg); + if (RSA_private_decrypt (sizeof (encr.rsa), + (const unsigned char *)&encr.rsa, (unsigned char *)rsa_decrypt, + key, RSA_PKCS1_OAEP_PADDING) != sizeof (auth.rsa)) + return 0; - push_back (e); + memcpy (&auth.rsa, rsa_decrypt, sizeof (auth.rsa)); + memcpy (&auth.ecdh, &encr.ecdh, sizeof (auth.ecdh)); - if (!cleaner.is_active ()) - cleaner.again (); - } + return 1; +} - rsa_cache () - { - cleaner.set (this); - cleaner.set (RSA_TTL, RSA_TTL); - } +static void +auth_hash (const auth_data &auth, auth_mac &mac) +{ + HMAC_CTX ctx; -} rsa_cache; + HMAC_CTX_init (&ctx); + require (HMAC_Init_ex (&ctx, auth.rsa.auth_key, sizeof (auth.rsa.auth_key), AUTH_DIGEST (), 0)); + require (HMAC_Update (&ctx, (const unsigned char *)&auth, sizeof auth)); + require (HMAC_Final (&ctx, (unsigned char *)&mac, 0)); + HMAC_CTX_cleanup (&ctx); +} void -rsa_cache::cleaner_cb (ev::timer &w, int revents) +connection::generate_auth_data () { - if (empty ()) - w.stop (); - else + if (auth_expire < ev_now ()) { - for (iterator i = begin (); i != end (); ) - if (i->expire <= ev_now ()) - i = erase (i); - else - ++i; + // request data + rand_fill (snd_auth.rsa); + curve25519_generate (snd_ecdh_a, snd_auth.ecdh); + auth_hash (snd_auth, snd_auth_mac); + + // eventual response data + curve25519_generate (rcv_ecdh_a, rcv_ecdh_b); } + + // every use prolongs the expiry + auth_expire = ev_now () + AUTH_TTL; } ////////////////////////////////////////////////////////////////////////////// @@ -376,10 +376,10 @@ HMAC_CTX *hctx = &ctx->hctx; - HMAC_Init_ex (hctx, 0, 0, 0, 0); - HMAC_Update (hctx, ((unsigned char *) this) + sizeof (hmac_packet), - len - sizeof (hmac_packet)); - HMAC_Final (hctx, (unsigned char *) &hmac_digest, &xlen); + require (HMAC_Init_ex (hctx, 0, 0, 0, 0)); + require (HMAC_Update (hctx, ((unsigned char *) this) + sizeof (hmac_packet), + len - sizeof (hmac_packet))); + require (HMAC_Final (hctx, (unsigned char *) &hmac_digest, &xlen)); } void @@ -453,7 +453,7 @@ } #endif - require (EVP_EncryptInit_ex (cctx, 0, 0, 0, 0)); + require (EVP_CipherInit_ex (cctx, 0, 0, 0, 0, 1)); struct { #if RAND_SIZE @@ -464,7 +464,7 @@ datahdr.seqno = ntohl (seqno); #if RAND_SIZE - RAND_pseudo_bytes ((unsigned char *) datahdr.rnd, RAND_SIZE); + require (RAND_pseudo_bytes ((unsigned char *) datahdr.rnd, RAND_SIZE) >= 0); #endif require (EVP_EncryptUpdate (cctx, @@ -496,7 +496,7 @@ u8 *d; u32 l = len - data_hdr_size (); - require (EVP_DecryptInit_ex (cctx, 0, 0, 0, 0)); + require (EVP_CipherInit_ex (cctx, 0, 0, 0, 0, 0)); #if ENABLE_COMPRESSION u8 cdata[MAX_MTU]; @@ -505,9 +505,15 @@ d = cdata; else #endif - d = &(*p)[6 + 6 - DATAHDR]; + d = &(*p)[6 + 6] - DATAHDR; - /* this overwrites part of the src mac, but we fix that later */ + // we play do evil games with the struct layout atm. + // pending better solutions, we at least do some verification. + // this is fine, as we left ISO territory long ago. + require (DATAHDR <= 16); + require ((u8 *)(&p->len + 1) == &(*p)[0]); + + // this can overwrite the len/dst/src fields require (EVP_DecryptUpdate (cctx, d, &outl2, (unsigned char *)&data, len - data_hdr_size ())); @@ -548,12 +554,9 @@ struct config_packet : vpn_packet { - // actually, hmaclen cannot be checked because the hmac - // field comes before this data, so peers with other - // hmacs simply will not work. - u8 prot_major, prot_minor, randsize, hmaclen; - u8 flags, challengelen, features, pad3; - u32 cipher_nid, digest_nid, hmac_nid; + u8 prot_major, prot_minor, randsize; + u8 flags, features, pad6, pad7, pad8; + u32 cipher_nid, mac_nid, auth_nid; void setup (ptype type, int dst); bool chk_config () const; @@ -580,14 +583,12 @@ prot_major = PROTOCOL_MAJOR; prot_minor = PROTOCOL_MINOR; randsize = RAND_SIZE; - hmaclen = HMACLENGTH; flags = 0; - challengelen = sizeof (rsachallenge); features = get_features (); - cipher_nid = htonl (EVP_CIPHER_nid (CIPHER)); - digest_nid = htonl (EVP_MD_type (RSA_HASH)); - hmac_nid = htonl (EVP_MD_type (DIGEST)); + cipher_nid = htonl (EVP_CIPHER_nid (CIPHER ())); + mac_nid = htonl (EVP_MD_type (MAC_DIGEST ())); + auth_nid = htonl (EVP_MD_type (AUTH_DIGEST ())); len = sizeof (*this) - sizeof (net_packet); set_hdr (type, dst); @@ -600,35 +601,30 @@ slog (L_WARN, _("major version mismatch (remote %d <=> local %d)"), prot_major, PROTOCOL_MAJOR); else if (randsize != RAND_SIZE) slog (L_WARN, _("rand size mismatch (remote %d <=> local %d)"), randsize, RAND_SIZE); - else if (hmaclen != HMACLENGTH) - slog (L_WARN, _("hmac length mismatch (remote %d <=> local %d)"), hmaclen, HMACLENGTH); - else if (challengelen != sizeof (rsachallenge)) - slog (L_WARN, _("challenge length mismatch (remote %d <=> local %d)"), challengelen, sizeof (rsachallenge)); - else if (cipher_nid != htonl (EVP_CIPHER_nid (CIPHER))) - slog (L_WARN, _("cipher mismatch (remote %x <=> local %x)"), ntohl (cipher_nid), EVP_CIPHER_nid (CIPHER)); - else if (digest_nid != htonl (EVP_MD_type (RSA_HASH))) - slog (L_WARN, _("digest mismatch (remote %x <=> local %x)"), ntohl (digest_nid), EVP_MD_type (RSA_HASH)); - else if (hmac_nid != htonl (EVP_MD_type (DIGEST))) - slog (L_WARN, _("hmac mismatch (remote %x <=> local %x)"), ntohl (hmac_nid), EVP_MD_type (DIGEST)); + else if (cipher_nid != htonl (EVP_CIPHER_nid (CIPHER ()))) + slog (L_WARN, _("cipher algo mismatch (remote %x <=> local %x)"), ntohl (cipher_nid), EVP_CIPHER_nid (CIPHER ())); + else if (mac_nid != htonl (EVP_MD_type (MAC_DIGEST ()))) + slog (L_WARN, _("mac algo mismatch (remote %x <=> local %x)"), ntohl (mac_nid), EVP_MD_type (MAC_DIGEST ())); + else if (auth_nid != htonl (EVP_MD_type (AUTH_DIGEST ()))) + slog (L_WARN, _("auth algo mismatch (remote %x <=> local %x)"), ntohl (auth_nid), EVP_MD_type (AUTH_DIGEST ())); else return true; return false; } -struct auth_req_packet : config_packet +struct auth_req_packet : config_packet // UNPROTECTED { char magic[8]; u8 initiate; // false if this is just an automatic reply u8 protocols; // supported protocols (will be patched on forward) u8 pad2, pad3; - rsaid id; - rsaencrdata encr; + auth_encr encr; auth_req_packet (int dst, bool initiate_, u8 protocols_) { config_packet::setup (PT_AUTH_REQ, dst); - strncpy (magic, MAGIC_OLD, 8); + memcpy (magic, MAGIC, 8); initiate = !!initiate_; protocols = protocols_; @@ -636,12 +632,9 @@ } }; -struct auth_res_packet : config_packet +struct auth_res_packet : config_packet // UNPROTECTED { - rsaid id; - u8 pad1, pad2, pad3; - u8 response_len; // encrypted length - rsaresponse response; + auth_response response; auth_res_packet (int dst) { @@ -685,15 +678,38 @@ ///////////////////////////////////////////////////////////////////////////// void -connection::connection_established () +connection::connection_established (const sockinfo &rsi) { - slog (L_NOISE, _("%s: possible connection establish (ictx %d, octx %d)"), conf->nodename, !!ictx, !!octx); + if (!have_snd_auth || !have_rcv_auth) + return; + + si = rsi; + protocol = rsi.prot; + + slog (L_INFO, _("%s(%s): connection established (%s), protocol version %d.%d."), + conf->nodename, (const char *)rsi, + is_direct ? "direct" : "forwarded", + PROTOCOL_MAJOR, prot_minor); + + if (::conf.script_node_up) + { + run_script_cb *cb = new run_script_cb; + cb->set (this); + run_script_queued (cb, _("node-up command execution failed, continuing.")); + } + + delete ictx; ictx = new crypto_ctx (rcv_auth, snd_auth, rcv_ecdh_a, rcv_auth.ecdh, 0); + iseqno.reset (ntohl (rcv_auth.rsa.seqno) & 0x7fffffff); + + delete octx; octx = new crypto_ctx (snd_auth, rcv_auth, snd_ecdh_a, snd_ecdh_b , 1); + oseqno = ntohl (snd_auth.rsa.seqno) & 0x7fffffff; if (ictx && octx) { // make sure rekeying timeouts are slightly asymmetric ev::tstamp rekey_interval = ::conf.rekey + (conf->id > THISNODE->id ? 10 : 0); rekey.start (rekey_interval, rekey_interval); + keepalive.start (::conf.keepalive); // send queued packets @@ -714,6 +730,7 @@ vpn->connection_established (this); } +#if 0 else { retry_cnt = 0; @@ -721,6 +738,7 @@ keepalive.stop (); rekey.stop (); } +#endif } void @@ -776,7 +794,6 @@ pkt->setup (conf->id, pong ? ping_packet::PT_PONG : ping_packet::PT_PING); slog (L_TRACE, "%s << %s [%s]", conf->nodename, pong ? "PT_PONG" : "PT_PING", (const char *)si); - send_vpn_packet (pkt, si, IPTOS_LOWDELAY); delete pkt; @@ -801,30 +818,24 @@ { auth_req_packet *pkt = new auth_req_packet (conf->id, initiate, THISNODE->protocols); - rsachallenge chg; - rsa_cache.gen (pkt->id, chg); - rsa_encrypt (conf->rsa_key, chg, pkt->encr); + generate_auth_data (); + auth_encrypt (conf->rsa_key, snd_auth, pkt->encr); slog (L_TRACE, "%s << PT_AUTH_REQ [%s]", conf->nodename, (const char *)si); - send_vpn_packet (pkt, si, IPTOS_RELIABILITY | IPTOS_LOWDELAY); // rsa is very very costly delete pkt; } void -connection::send_auth_response (const sockinfo &si, const rsaid &id, const rsachallenge &chg) +connection::send_auth_response (const sockinfo &si) { auth_res_packet *pkt = new auth_res_packet (conf->id); - pkt->id = id; - - rsa_hash (id, chg, pkt->response); - - pkt->hmac_set (octx); + auth_hash (rcv_auth, pkt->response.mac); + memcpy (pkt->response.ecdh, rcv_ecdh_b, sizeof (rcv_ecdh_b)); slog (L_TRACE, "%s << PT_AUTH_RES [%s]", conf->nodename, (const char *)si); - send_vpn_packet (pkt, si, IPTOS_RELIABILITY); // rsa is very very costly delete pkt; @@ -929,6 +940,10 @@ si.host = 0; + have_snd_auth = false; + have_rcv_auth = false; + auth_expire = 0.; + last_activity = 0.; //last_si_change = 0.; retry_cnt = 0; @@ -1073,8 +1088,7 @@ conf->nodename, p->initiate ? "initiate" : "reply", p->protocols, p->features); - if (p->chk_config () - && (!memcmp (p->magic, MAGIC_OLD, 8) || !memcmp (p->magic, MAGIC, 8))) + if (p->chk_config () && !memcmp (p->magic, MAGIC, 8)) { if (p->prot_minor != PROTOCOL_MINOR) slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), @@ -1084,30 +1098,32 @@ if (p->initiate) send_auth_request (rsi, false); - rsachallenge k; + auth_data auth; - if (!rsa_decrypt (::conf.rsa_key, p->encr, k)) + if (!auth_decrypt (::conf.rsa_key, p->encr, auth)) { slog (L_ERR, _("%s(%s): challenge illegal or corrupted (%s). mismatched key or config file?"), conf->nodename, (const char *)rsi, ERR_error_string (ERR_get_error (), 0)); - break; } else { - delete octx; - - octx = new crypto_ctx (k, 1); - oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff; + bool chg = !have_rcv_auth || memcmp (&rcv_auth, &auth, sizeof auth); - conf->protocols = p->protocols; - features = p->features & config_packet::get_features (); + rcv_auth = auth; + have_rcv_auth = true; - send_auth_response (rsi, p->id, k); + send_auth_response (rsi); - connection_established (); + if (chg) + { + conf->protocols = p->protocols; + features = p->features & config_packet::get_features (); - break; + connection_established (rsi); + } } + + break; } else slog (L_WARN, _("%s(%s): protocol mismatch."), @@ -1126,70 +1142,26 @@ if (p->chk_config ()) { - if (p->prot_minor != PROTOCOL_MINOR) - slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), - conf->nodename, (const char *)rsi, - PROTOCOL_MINOR, conf->nodename, p->prot_minor); - - rsachallenge chg; - - if (!rsa_cache.find (p->id, chg)) + if (memcmp (&p->response.mac, snd_auth_mac, sizeof (snd_auth_mac))) { - slog (L_ERR, _("%s(%s): unrequested auth response, ignoring."), + slog (L_ERR, _("%s(%s): unrequested or outdated auth response, ignoring."), conf->nodename, (const char *)rsi); - break; } - else + else if (!have_snd_auth) { - crypto_ctx *cctx = new crypto_ctx (chg, 0); + if (p->prot_minor != PROTOCOL_MINOR) + slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), + conf->nodename, (const char *)rsi, + PROTOCOL_MINOR, conf->nodename, p->prot_minor); - if (!p->hmac_chk (cctx)) - { - slog (L_ERR, _("%s(%s): hmac authentication error on auth response, received invalid packet\n" - "could be an attack, or just corruption or a synchronization error."), - conf->nodename, (const char *)rsi); - break; - } - else - { - rsaresponse h; - - rsa_hash (p->id, chg, h); - - if (!memcmp ((u8 *)&h, (u8 *)p->response, sizeof h)) - { - prot_minor = p->prot_minor; - - delete ictx; ictx = cctx; - - iseqno.reset (ntohl (*(u32 *)&chg[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid - - si = rsi; - protocol = rsi.prot; - - slog (L_INFO, _("%s(%s): connection established (%s), protocol version %d.%d."), - conf->nodename, (const char *)rsi, - is_direct ? "direct" : "forwarded", - p->prot_major, p->prot_minor); - - connection_established (); - - if (::conf.script_node_up) - { - run_script_cb *cb = new run_script_cb; - cb->set (this); - run_script_queued (cb, _("node-up command execution failed, continuing.")); - } - - break; - } - else - slog (L_ERR, _("%s(%s): sent and received challenge do not match."), - conf->nodename, (const char *)rsi); - } + prot_minor = p->prot_minor; + memcpy (snd_ecdh_b, p->response.ecdh, sizeof (snd_ecdh_b)); - delete cctx; + have_snd_auth = true; + connection_established (rsi); } + + break; } } @@ -1347,23 +1319,25 @@ inline void connection::keepalive_cb (ev::timer &w, int revents) { - if (ev_now () >= last_activity + ::conf.keepalive + 15) + ev_tstamp when = last_activity + ::conf.keepalive - ev::now (); + + if (when >= 0) + w.start (when); + else if (when < -15) { reset_connection (); establish_connection (); } - else if (ev_now () < last_activity + ::conf.keepalive) - w.start (last_activity + ::conf.keepalive - ev::now ()); else if (conf->connectmode != conf_node::C_ONDEMAND || THISNODE->connectmode != conf_node::C_ONDEMAND) { - send_ping (si); w.start (3); + send_ping (si); } - else if (ev_now () < last_activity + ::conf.keepalive + 10) + else if (when >= -10) // hold ondemand connections implicitly a few seconds longer // should delete octx, though, or something like that ;) - w.start (last_activity + ::conf.keepalive + 10 - ev::now ()); + w.start (when + 10); else reset_connection (); }