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Comparing gvpe/src/protocol.C (file contents):
Revision 1.13 by pcg, Sat Mar 22 22:34:36 2003 UTC vs.
Revision 1.18 by pcg, Wed Mar 26 02:15:38 2003 UTC

… …
58 58
59static time_t next_timecheck; 59static time_t next_timecheck;
60 60
61#define MAGIC "vped\xbd\xc6\xdb\x82" // 8 bytes of magic 61#define MAGIC "vped\xbd\xc6\xdb\x82" // 8 bytes of magic
62 62
63static const rsachallenge & 63struct crypto_ctx
64challenge_bytes ()
65{
66 static rsachallenge challenge;
67 static double challenge_ttl; // time this challenge needs to be recreated
68
69 if (NOW > challenge_ttl)
70 { 64 {
71 RAND_bytes ((unsigned char *)&challenge, sizeof (challenge)); 65 EVP_CIPHER_CTX cctx;
72 challenge_ttl = NOW + CHALLENGE_TTL; 66 HMAC_CTX hctx;
73 }
74 67
75 return challenge; 68 crypto_ctx (const rsachallenge &challenge, int enc);
76} 69 ~crypto_ctx ();
70 };
77 71
78// caching of rsa operations really helps slow computers 72crypto_ctx::crypto_ctx (const rsachallenge &challenge, int enc)
73{
74 EVP_CIPHER_CTX_init (&cctx);
75 EVP_CipherInit_ex (&cctx, CIPHER, 0, &challenge[CHG_CIPHER_KEY], 0, enc);
76 HMAC_CTX_init (&hctx);
77 HMAC_Init_ex (&hctx, &challenge[CHG_HMAC_KEY], HMAC_KEYLEN, DIGEST, 0);
78}
79
80crypto_ctx::~crypto_ctx ()
81{
82 EVP_CIPHER_CTX_cleanup (&cctx);
83 HMAC_CTX_cleanup (&hctx);
84}
85
86static void
87rsa_hash (const rsachallenge &chg, rsaresponse &h)
88{
89 EVP_MD_CTX ctx;
90
91 EVP_MD_CTX_init (&ctx);
92 EVP_DigestInit (&ctx, RSA_HASH);
93 EVP_DigestUpdate(&ctx, &chg, sizeof chg);
94 EVP_DigestFinal (&ctx, (unsigned char *)&h, 0);
95 EVP_MD_CTX_cleanup (&ctx);
96}
97
79struct rsa_entry { 98struct rsa_entry {
80 tstamp expire; 99 tstamp expire;
100 rsaid id;
81 rsachallenge chg; 101 rsachallenge chg;
82 RSA *key; // which key
83 rsaencrdata encr;
84
85 rsa_entry ()
86 {
87 expire = NOW + CHALLENGE_TTL;
88 }
89}; 102};
90 103
91struct rsa_cache : list<rsa_entry> 104struct rsa_cache : list<rsa_entry>
92{ 105{
93 void cleaner_cb (tstamp &ts); time_watcher cleaner; 106 void cleaner_cb (tstamp &ts); time_watcher cleaner;
94 107
95 const rsaencrdata *public_encrypt (RSA *key, const rsachallenge &chg) 108 bool find (const rsaid &id, rsachallenge &chg)
96 { 109 {
97 for (iterator i = begin (); i != end (); ++i) 110 for (iterator i = begin (); i != end (); ++i)
98 { 111 {
99 if (i->key == key && !memcmp (&chg, &i->chg, sizeof chg)) 112 if (!memcmp (&id, &i->id, sizeof id) && i->expire > NOW)
100 return &i->encr; 113 {
114 memcpy (&chg, &i->chg, sizeof chg);
115
116 erase (i);
117 return true;
118 }
101 } 119 }
102 120
103 if (cleaner.at < NOW) 121 if (cleaner.at < NOW)
104 cleaner.start (NOW + CHALLENGE_TTL); 122 cleaner.start (NOW + RSA_TTL);
105 123
106 resize (size () + 1); 124 return false;
107 rsa_entry *e = &(*rbegin ()); 125 }
108 126
109 e->key = key; 127 void gen (rsaid &id, rsachallenge &chg)
128 {
129 rsa_entry e;
130
131 RAND_bytes ((unsigned char *)&id, sizeof id);
132 RAND_bytes ((unsigned char *)&chg, sizeof chg);
133
134 e.expire = NOW + RSA_TTL;
135 e.id = id;
110 memcpy (&e->chg, &chg, sizeof chg); 136 memcpy (&e.chg, &chg, sizeof chg);
111 137
112 if (0 > RSA_public_encrypt (sizeof chg, 138 push_back (e);
113 (unsigned char *)&chg, (unsigned char *)&e->encr,
114 key, RSA_PKCS1_OAEP_PADDING))
115 fatal ("RSA_public_encrypt error");
116
117 return &e->encr;
118 }
119
120 const rsachallenge *private_decrypt (RSA *key, const rsaencrdata &encr)
121 {
122 for (iterator i = begin (); i != end (); ++i)
123 if (i->key == key && !memcmp (&encr, &i->encr, sizeof encr))
124 return &i->chg;
125 139
126 if (cleaner.at < NOW) 140 if (cleaner.at < NOW)
127 cleaner.start (NOW + CHALLENGE_TTL); 141 cleaner.start (NOW + RSA_TTL);
128
129 resize (size () + 1);
130 rsa_entry *e = &(*rbegin ());
131
132 e->key = key;
133 memcpy (&e->encr, &encr, sizeof encr);
134
135 if (0 > RSA_private_decrypt (sizeof encr,
136 (unsigned char *)&encr, (unsigned char *)&e->chg,
137 key, RSA_PKCS1_OAEP_PADDING))
138 {
139 pop_back ();
140 return 0;
141 }
142
143 return &e->chg;
144 } 142 }
145 143
146 rsa_cache () 144 rsa_cache ()
147 : cleaner (this, &rsa_cache::cleaner_cb) 145 : cleaner (this, &rsa_cache::cleaner_cb)
148 { } 146 { }
… …
153{ 151{
154 if (empty ()) 152 if (empty ())
155 ts = TSTAMP_CANCEL; 153 ts = TSTAMP_CANCEL;
156 else 154 else
157 { 155 {
158 ts = NOW + 3; 156 ts = NOW + RSA_TTL;
157
159 for (iterator i = begin (); i != end (); ) 158 for (iterator i = begin (); i != end (); )
160 {
161 if (i->expire >= NOW) 159 if (i->expire <= NOW)
162 i = erase (i); 160 i = erase (i);
163 else 161 else
164 ++i; 162 ++i;
165 }
166 } 163 }
167} 164}
168 165
169// run a script. yes, it's a template function. yes, c++ 166typedef callback<const char *, int> run_script_cb;
170// is not a functional language. yes, this suxx. 167
171template<class owner> 168// run a shell script (or actually an external program).
172static void 169static void
173run_script (owner *obj, const char *(owner::*setup)(), bool wait) 170run_script (const run_script_cb &cb, bool wait)
174{ 171{
175 int pid; 172 int pid;
176 173
177 if ((pid = fork ()) == 0) 174 if ((pid = fork ()) == 0)
178 { 175 {
179 char *filename; 176 char *filename;
180 asprintf (&filename, "%s/%s", confbase, (obj->*setup) ()); 177 asprintf (&filename, "%s/%s", confbase, cb(0));
181 execl (filename, filename, (char *) 0); 178 execl (filename, filename, (char *) 0);
182 exit (255); 179 exit (255);
183 } 180 }
184 else if (pid > 0) 181 else if (pid > 0)
185 { 182 {
… …
189 /* TODO: check status */ 186 /* TODO: check status */
190 } 187 }
191 } 188 }
192} 189}
193 190
194// xor the socket address into the challenge to ensure different challenges
195// per host. we could rely on the OAEP padding, but this doesn't hurt.
196void
197xor_sa (rsachallenge &k, SOCKADDR *sa)
198{
199 ((u32 *) k)[(CHG_CIPHER_KEY + 0) / 4] ^= sa->sin_addr.s_addr;
200 ((u16 *) k)[(CHG_CIPHER_KEY + 4) / 2] ^= sa->sin_port;
201 ((u32 *) k)[(CHG_HMAC_KEY + 0) / 4] ^= sa->sin_addr.s_addr;
202 ((u16 *) k)[(CHG_HMAC_KEY + 4) / 2] ^= sa->sin_port;
203}
204
205struct crypto_ctx
206 {
207 EVP_CIPHER_CTX cctx;
208 HMAC_CTX hctx;
209
210 crypto_ctx (const rsachallenge &challenge, int enc);
211 ~crypto_ctx ();
212 };
213
214crypto_ctx::crypto_ctx (const rsachallenge &challenge, int enc)
215{
216 EVP_CIPHER_CTX_init (&cctx);
217 EVP_CipherInit_ex (&cctx, CIPHER, 0, &challenge[CHG_CIPHER_KEY], 0, enc);
218 HMAC_CTX_init (&hctx);
219 HMAC_Init_ex (&hctx, &challenge[CHG_HMAC_KEY], HMAC_KEYLEN, DIGEST, 0);
220}
221
222crypto_ctx::~crypto_ctx ()
223{
224 EVP_CIPHER_CTX_cleanup (&cctx);
225 HMAC_CTX_cleanup (&hctx);
226}
227
228////////////////////////////////////////////////////////////////////////////// 191//////////////////////////////////////////////////////////////////////////////
229 192
230void pkt_queue::put (tap_packet *p) 193void pkt_queue::put (tap_packet *p)
231{ 194{
232 if (queue[i]) 195 if (queue[i])
… …
264{ 227{
265 for (i = QUEUEDEPTH; --i > 0; ) 228 for (i = QUEUEDEPTH; --i > 0; )
266 delete queue[i]; 229 delete queue[i];
267} 230}
268 231
232struct net_rateinfo {
233 u32 host;
234 double pcnt, diff;
235 tstamp last;
236};
237
269// only do action once every x seconds per host. 238// only do action once every x seconds per host whole allowing bursts.
270// currently this is quite a slow implementation, 239// this implementation ("splay list" ;) is inefficient,
271// but suffices for normal operation. 240// but low on resources.
272struct u32_rate_limiter : private map<u32, tstamp> 241struct net_rate_limiter : private list<net_rateinfo>
273 { 242{
274 tstamp every; 243 static const double ALPHA = 1. - 1. / 90.; // allow bursts
244 static const double CUTOFF = 20.; // one event every CUTOFF seconds
245 static const double EXPIRE = CUTOFF * 30.; // expire entries after this time
275 246
276 bool can (u32 host); 247 bool can (u32 host);
277
278 u32_rate_limiter (tstamp every = 1)
279 {
280 this->every = every;
281 }
282 };
283
284struct net_rate_limiter : u32_rate_limiter
285 {
286 bool can (SOCKADDR *sa) { return u32_rate_limiter::can((u32)sa->sin_addr.s_addr); } 248 bool can (SOCKADDR *sa) { return can((u32)sa->sin_addr.s_addr); }
287 bool can (sockinfo &si) { return u32_rate_limiter::can((u32)si.host); } 249 bool can (sockinfo &si) { return can((u32)si.host); }
250};
288 251
289 net_rate_limiter (tstamp every) : u32_rate_limiter (every) {} 252net_rate_limiter auth_rate_limiter, reset_rate_limiter;
290 };
291 253
292bool u32_rate_limiter::can (u32 host) 254bool net_rate_limiter::can (u32 host)
293{ 255{
294 iterator i; 256 iterator i;
295 257
296 for (i = begin (); i != end (); ) 258 for (i = begin (); i != end (); )
297 if (i->second <= NOW) 259 if (i->host == host)
298 { 260 break;
261 else if (i->last < NOW - EXPIRE)
299 erase (i); 262 i = erase (i);
300 i = begin ();
301 }
302 else 263 else
303 ++i; 264 i++;
304 265
305 i = find (host);
306
307 if (i != end ()) 266 if (i == end ())
308 return false; 267 {
268 net_rateinfo ri;
309 269
310 insert (value_type (host, NOW + every)); 270 ri.host = host;
271 ri.pcnt = 1.;
272 ri.diff = CUTOFF * (1. / (1. - ALPHA));
273 ri.last = NOW;
311 274
275 push_front (ri);
276
312 return true; 277 return true;
278 }
279 else
280 {
281 net_rateinfo ri (*i);
282 erase (i);
283
284 ri.pcnt = ri.pcnt * ALPHA;
285 ri.diff = ri.diff * ALPHA + (NOW - ri.last);
286
287 ri.last = NOW;
288
289 bool send = ri.diff / ri.pcnt > CUTOFF;
290
291 if (send)
292 ri.pcnt++;
293
294 push_front (ri);
295
296 return send;
297 }
313} 298}
314 299
315///////////////////////////////////////////////////////////////////////////// 300/////////////////////////////////////////////////////////////////////////////
316 301
317static void next_wakeup (time_t next) 302static void next_wakeup (time_t next)
… …
321} 306}
322 307
323static unsigned char hmac_digest[EVP_MAX_MD_SIZE]; 308static unsigned char hmac_digest[EVP_MAX_MD_SIZE];
324 309
325struct hmac_packet:net_packet 310struct hmac_packet:net_packet
311{
312 u8 hmac[HMACLENGTH]; // each and every packet has a hmac field, but that is not (yet) checked everywhere
313
314 void hmac_set (crypto_ctx * ctx);
315 bool hmac_chk (crypto_ctx * ctx);
316
317private:
318 void hmac_gen (crypto_ctx * ctx)
326 { 319 {
327 u8 hmac[HMACLENGTH]; // each and every packet has a hmac field, but that is not (yet) checked everywhere
328
329 void hmac_set (crypto_ctx * ctx);
330 bool hmac_chk (crypto_ctx * ctx);
331
332private:
333 void hmac_gen (crypto_ctx * ctx)
334 {
335 unsigned int xlen; 320 unsigned int xlen;
336 HMAC_CTX *hctx = &ctx->hctx; 321 HMAC_CTX *hctx = &ctx->hctx;
337 322
338 HMAC_Init_ex (hctx, 0, 0, 0, 0); 323 HMAC_Init_ex (hctx, 0, 0, 0, 0);
339 HMAC_Update (hctx, ((unsigned char *) this) + sizeof (hmac_packet), 324 HMAC_Update (hctx, ((unsigned char *) this) + sizeof (hmac_packet),
340 len - sizeof (hmac_packet)); 325 len - sizeof (hmac_packet));
341 HMAC_Final (hctx, (unsigned char *) &hmac_digest, &xlen); 326 HMAC_Final (hctx, (unsigned char *) &hmac_digest, &xlen);
342 }
343 }; 327 }
328};
344 329
345void 330void
346hmac_packet::hmac_set (crypto_ctx * ctx) 331hmac_packet::hmac_set (crypto_ctx * ctx)
347{ 332{
348 hmac_gen (ctx); 333 hmac_gen (ctx);
… …
364 { 349 {
365 PT_RESET = 0, 350 PT_RESET = 0,
366 PT_DATA_UNCOMPRESSED, 351 PT_DATA_UNCOMPRESSED,
367 PT_DATA_COMPRESSED, 352 PT_DATA_COMPRESSED,
368 PT_PING, PT_PONG, // wasting namespace space? ;) 353 PT_PING, PT_PONG, // wasting namespace space? ;)
369 PT_AUTH, // authentification 354 PT_AUTH_REQ, // authentification request
355 PT_AUTH_RES, // authentification response
370 PT_CONNECT_REQ, // want other host to contact me 356 PT_CONNECT_REQ, // want other host to contact me
371 PT_CONNECT_INFO, // request connection to some node 357 PT_CONNECT_INFO, // request connection to some node
372 PT_REKEY, // rekeying (not yet implemented)
373 PT_MAX 358 PT_MAX
374 }; 359 };
375 360
376 u8 type; 361 u8 type;
377 u8 srcdst, src1, dst1; 362 u8 srcdst, src1, dst1;
… …
525 510
526 return p; 511 return p;
527} 512}
528 513
529struct ping_packet : vpn_packet 514struct ping_packet : vpn_packet
515{
516 void setup (int dst, ptype type)
530 { 517 {
531 void setup (int dst, ptype type)
532 {
533 set_hdr (type, dst); 518 set_hdr (type, dst);
534 len = sizeof (*this) - sizeof (net_packet); 519 len = sizeof (*this) - sizeof (net_packet);
535 }
536 }; 520 }
521};
537 522
538struct config_packet : vpn_packet 523struct config_packet : vpn_packet
524{
525 // actually, hmaclen cannot be checked because the hmac
526 // field comes before this data, so peers with other
527 // hmacs simply will not work.
528 u8 prot_major, prot_minor, randsize, hmaclen;
529 u8 flags, challengelen, pad2, pad3;
530 u32 cipher_nid, digest_nid, hmac_nid;
531
532 const u8 curflags () const
539 { 533 {
540 // actually, hmaclen cannot be checked because the hmac
541 // field comes before this data, so peers with other
542 // hmacs simply will not work.
543 u8 prot_major, prot_minor, randsize, hmaclen;
544 u8 flags, challengelen, pad2, pad3;
545 u32 cipher_nid;
546 u32 digest_nid;
547
548 const u8 curflags () const
549 {
550 return 0x80 534 return 0x80
551 | 0x02
552#if PROTOCOL_MAJOR != 2
553#error hi
554#endif
555 | (ENABLE_COMPRESSION ? 0x01 : 0x00); 535 | (ENABLE_COMPRESSION ? 0x01 : 0x00);
556 } 536 }
557 537
558 void setup (ptype type, int dst) 538 void setup (ptype type, int dst)
559 {
560 prot_major = PROTOCOL_MAJOR;
561 prot_minor = PROTOCOL_MINOR;
562 randsize = RAND_SIZE;
563 hmaclen = HMACLENGTH;
564 flags = curflags ();
565 challengelen = sizeof (rsachallenge);
566
567 cipher_nid = htonl (EVP_CIPHER_nid (CIPHER));
568 digest_nid = htonl (EVP_MD_type (DIGEST));
569
570 len = sizeof (*this) - sizeof (net_packet);
571 set_hdr (type, dst);
572 }
573
574 bool chk_config ()
575 {
576 return prot_major == PROTOCOL_MAJOR
577 && randsize == RAND_SIZE
578 && hmaclen == HMACLENGTH
579 && flags == curflags ()
580 && challengelen == sizeof (rsachallenge)
581 && cipher_nid == htonl (EVP_CIPHER_nid (CIPHER))
582 && digest_nid == htonl (EVP_MD_type (DIGEST));
583 }
584 };
585
586struct auth_packet : config_packet
587 { 539 {
588 char magic[8]; 540 prot_major = PROTOCOL_MAJOR;
589 u8 subtype; 541 prot_minor = PROTOCOL_MINOR;
590 u8 pad1, pad2; 542 randsize = RAND_SIZE;
591 rsaencrdata challenge; 543 hmaclen = HMACLENGTH;
544 flags = curflags ();
545 challengelen = sizeof (rsachallenge);
592 546
593 auth_packet (int dst, auth_subtype stype) 547 cipher_nid = htonl (EVP_CIPHER_nid (CIPHER));
594 { 548 digest_nid = htonl (EVP_MD_type (RSA_HASH));
595 config_packet::setup (PT_AUTH, dst); 549 hmac_nid = htonl (EVP_MD_type (DIGEST));
596 subtype = stype; 550
597 len = sizeof (*this) - sizeof (net_packet); 551 len = sizeof (*this) - sizeof (net_packet);
552 set_hdr (type, dst);
553 }
554
555 bool chk_config ()
556 {
557 return prot_major == PROTOCOL_MAJOR
558 && randsize == RAND_SIZE
559 && hmaclen == HMACLENGTH
560 && flags == curflags ()
561 && challengelen == sizeof (rsachallenge)
562 && cipher_nid == htonl (EVP_CIPHER_nid (CIPHER))
563 && digest_nid == htonl (EVP_MD_type (RSA_HASH))
564 && hmac_nid == htonl (EVP_MD_type (DIGEST));
565 }
566};
567
568struct auth_req_packet : config_packet
569{
570 char magic[8];
571 u8 initiate; // false if this is just an automatic reply
572 u8 pad1, pad2, pad3;
573 rsaid id;
574 rsaencrdata encr;
575
576 auth_req_packet (int dst, bool initiate_)
577 {
578 config_packet::setup (PT_AUTH_REQ, dst);
579 initiate = !!initiate_;
598 strncpy (magic, MAGIC, 8); 580 strncpy (magic, MAGIC, 8);
599 } 581 len = sizeof (*this) - sizeof (net_packet);
600 }; 582 }
583};
584
585struct auth_res_packet : config_packet
586{
587 rsaid id;
588 rsaresponse response;
589
590 auth_res_packet (int dst)
591 {
592 config_packet::setup (PT_AUTH_RES, dst);
593 len = sizeof (*this) - sizeof (net_packet);
594 }
595};
601 596
602struct connect_req_packet : vpn_packet 597struct connect_req_packet : vpn_packet
598{
599 u8 id;
600 u8 pad1, pad2, pad3;
601
602 connect_req_packet (int dst, int id_)
603 { 603 {
604 u8 id; 604 id = id_;
605 u8 pad1, pad2, pad3;
606
607 connect_req_packet (int dst, int id)
608 {
609 this->id = id;
610 set_hdr (PT_CONNECT_REQ, dst); 605 set_hdr (PT_CONNECT_REQ, dst);
611 len = sizeof (*this) - sizeof (net_packet); 606 len = sizeof (*this) - sizeof (net_packet);
612 }
613 }; 607 }
608};
614 609
615struct connect_info_packet : vpn_packet 610struct connect_info_packet : vpn_packet
611{
612 u8 id;
613 u8 pad1, pad2, pad3;
614 sockinfo si;
615
616 connect_info_packet (int dst, int id_, sockinfo &si_)
616 { 617 {
617 u8 id; 618 id = id_;
618 u8 pad1, pad2, pad3; 619 si = si_;
619 sockinfo si;
620
621 connect_info_packet (int dst, int id, sockinfo &si)
622 {
623 this->id = id;
624 this->si = si;
625 set_hdr (PT_CONNECT_INFO, dst); 620 set_hdr (PT_CONNECT_INFO, dst);
626 len = sizeof (*this) - sizeof (net_packet); 621 len = sizeof (*this) - sizeof (net_packet);
627 }
628 }; 622 }
623};
629 624
630///////////////////////////////////////////////////////////////////////////// 625/////////////////////////////////////////////////////////////////////////////
631 626
632void 627void
633fill_sa (SOCKADDR *sa, conf_node *conf) 628fill_sa (SOCKADDR *sa, conf_node *conf)
… …
669} 664}
670 665
671void 666void
672connection::send_reset (SOCKADDR *dsa) 667connection::send_reset (SOCKADDR *dsa)
673{ 668{
674 static net_rate_limiter limiter(1);
675
676 if (limiter.can (dsa) && connectmode != conf_node::C_DISABLED) 669 if (reset_rate_limiter.can (dsa) && connectmode != conf_node::C_DISABLED)
677 { 670 {
678 config_packet *pkt = new config_packet; 671 config_packet *pkt = new config_packet;
679 672
680 pkt->setup (vpn_packet::PT_RESET, conf->id); 673 pkt->setup (vpn_packet::PT_RESET, conf->id);
681 vpn->send_vpn_packet (pkt, dsa, IPTOS_MINCOST); 674 vpn->send_vpn_packet (pkt, dsa, IPTOS_MINCOST);
682 675
683 delete pkt; 676 delete pkt;
684 } 677 }
685} 678}
686 679
687static rsachallenge *
688gen_challenge (u32 seqrand, SOCKADDR *sa)
689{
690 static rsachallenge k;
691
692 memcpy (&k, &challenge_bytes (), sizeof (k));
693 *(u32 *)&k[CHG_SEQNO] ^= seqrand;
694 xor_sa (k, sa);
695
696 return &k;
697}
698
699void 680void
700connection::send_auth (auth_subtype subtype, SOCKADDR *sa, const rsachallenge *k) 681connection::send_auth_request (SOCKADDR *sa, bool initiate)
701{ 682{
702 static net_rate_limiter limiter(0.2); 683 if (auth_rate_limiter.can (sa))
703
704 if (subtype != AUTH_INIT || limiter.can (sa))
705 { 684 {
706 if (!k)
707 k = gen_challenge (seqrand, sa);
708
709 auth_packet *pkt = new auth_packet (conf->id, subtype); 685 auth_req_packet *pkt = new auth_req_packet (conf->id, initiate);
710 686
711 memcpy (pkt->challenge, rsa_cache.public_encrypt (conf->rsa_key, *k), sizeof (rsaencrdata)); 687 rsachallenge chg;
712 688
689 rsa_cache.gen (pkt->id, chg);
690
691 if (0 > RSA_public_encrypt (sizeof chg,
692 (unsigned char *)&chg, (unsigned char *)&pkt->encr,
693 conf->rsa_key, RSA_PKCS1_OAEP_PADDING))
694 fatal ("RSA_public_encrypt error");
695
713 slog (L_TRACE, ">>%d PT_AUTH(%d) [%s]", conf->id, subtype, (const char *)sockinfo (sa)); 696 slog (L_TRACE, ">>%d PT_AUTH_REQ [%s]", conf->id, (const char *)sockinfo (sa));
714 697
715 vpn->send_vpn_packet (pkt, sa, IPTOS_RELIABILITY); 698 vpn->send_vpn_packet (pkt, sa, IPTOS_RELIABILITY); // rsa is very very costly
716 699
717 delete pkt; 700 delete pkt;
718 } 701 }
719} 702}
720 703
721void 704void
705connection::send_auth_response (SOCKADDR *sa, const rsaid &id, const rsachallenge &chg)
706{
707 if (auth_rate_limiter.can (sa))
708 {
709 auth_res_packet *pkt = new auth_res_packet (conf->id);
710
711 pkt->id = id;
712 rsa_hash (chg, pkt->response);
713
714 slog (L_TRACE, ">>%d PT_AUTH_RES [%s]", conf->id, (const char *)sockinfo (sa));
715
716 vpn->send_vpn_packet (pkt, sa, IPTOS_RELIABILITY); // rsa is very very costly
717
718 delete pkt;
719 }
720}
721
722void
722connection::establish_connection_cb (tstamp &ts) 723connection::establish_connection_cb (tstamp &ts)
723{ 724{
724 if (ictx || conf == THISNODE || connectmode == conf_node::C_NEVER) 725 if (ictx || conf == THISNODE
726 || connectmode == conf_node::C_NEVER
727 || connectmode == conf_node::C_DISABLED)
725 ts = TSTAMP_CANCEL; 728 ts = TSTAMP_CANCEL;
726 else if (ts <= NOW) 729 else if (ts <= NOW)
727 { 730 {
728 double retry_int = double (retry_cnt & 3 ? (retry_cnt & 3) : 1 << (retry_cnt >> 2)) * 0.25; 731 double retry_int = double (retry_cnt & 3 ? (retry_cnt & 3) : 1 << (retry_cnt >> 2)) * 0.6;
729 732
730 if (retry_int < 3600 * 8) 733 if (retry_int < 3600 * 8)
731 retry_cnt++; 734 retry_cnt++;
732
733 if (connectmode == conf_node::C_ONDEMAND
734 && retry_int > ::conf.keepalive)
735 retry_int = ::conf.keepalive;
736 735
737 ts = NOW + retry_int; 736 ts = NOW + retry_int;
738 737
739 if (conf->hostname) 738 if (conf->hostname)
740 { 739 {
741 reset_dstaddr (); 740 reset_dstaddr ();
742 if (sa.sin_addr.s_addr) 741 if (sa.sin_addr.s_addr)
743 if (retry_cnt < 4) 742 if (retry_cnt < 4)
744 send_auth (AUTH_INIT, &sa); 743 send_auth_request (&sa, true);
745 else 744 else if (auth_rate_limiter.can (&sa))
746 send_ping (&sa, 0); 745 send_ping (&sa, 0);
747 } 746 }
748 else 747 else
749 vpn->connect_request (conf->id); 748 vpn->connect_request (conf->id);
750 } 749 }
… …
756 if (ictx && octx) 755 if (ictx && octx)
757 { 756 {
758 slog (L_INFO, _("connection to %d (%s) lost"), conf->id, conf->nodename); 757 slog (L_INFO, _("connection to %d (%s) lost"), conf->id, conf->nodename);
759 758
760 if (::conf.script_node_down) 759 if (::conf.script_node_down)
761 run_script (this, &connection::script_node_down, false); 760 run_script (run_script_cb (this, &connection::script_node_down), false);
762 } 761 }
763 762
764 delete ictx; ictx = 0; 763 delete ictx; ictx = 0;
765 delete octx; octx = 0; 764 delete octx; octx = 0;
766
767 RAND_bytes ((unsigned char *)&seqrand, sizeof (u32));
768 765
769 sa.sin_port = 0; 766 sa.sin_port = 0;
770 sa.sin_addr.s_addr = 0; 767 sa.sin_addr.s_addr = 0;
771 768
772 last_activity = 0; 769 last_activity = 0;
… …
837 conf->id, pkt->typ (), pkt->src (), pkt->dst ()); 834 conf->id, pkt->typ (), pkt->src (), pkt->dst ());
838 835
839 switch (pkt->typ ()) 836 switch (pkt->typ ())
840 { 837 {
841 case vpn_packet::PT_PING: 838 case vpn_packet::PT_PING:
842 send_ping (ssa, 1); // pong
843 break;
844
845 case vpn_packet::PT_PONG:
846 // we send pings instead of auth packets after some retries, 839 // we send pings instead of auth packets after some retries,
847 // so reset the retry counter and establish a conenction 840 // so reset the retry counter and establish a conenction
848 // when we receive a pong. 841 // when we receive a pong.
849 if (!ictx && !octx) 842 if (!ictx && !octx)
850 { 843 {
851 retry_cnt = 0; 844 retry_cnt = 0;
852 establish_connection.at = 0; 845 establish_connection.at = 0;
853 establish_connection (); 846 establish_connection ();
854 } 847 }
848 else
849 send_ping (ssa, 1); // pong
855 850
851 break;
852
853 case vpn_packet::PT_PONG:
856 break; 854 break;
857 855
858 case vpn_packet::PT_RESET: 856 case vpn_packet::PT_RESET:
859 { 857 {
860 reset_connection (); 858 reset_connection ();
861 859
862 config_packet *p = (config_packet *) pkt; 860 config_packet *p = (config_packet *) pkt;
861
863 if (!p->chk_config ()) 862 if (!p->chk_config ())
864 { 863 {
865 slog (L_WARN, _("protocol mismatch, disabling node '%s'"), conf->nodename); 864 slog (L_WARN, _("protocol mismatch, disabling node '%s'"), conf->nodename);
866 connectmode = conf_node::C_DISABLED; 865 connectmode = conf_node::C_DISABLED;
867 } 866 }
868 else if (connectmode == conf_node::C_ALWAYS) 867 else if (connectmode == conf_node::C_ALWAYS)
869 establish_connection (); 868 establish_connection ();
870 } 869 }
871 break; 870 break;
872 871
873 case vpn_packet::PT_AUTH: 872 case vpn_packet::PT_AUTH_REQ:
874 { 873 {
875 auth_packet *p = (auth_packet *) pkt; 874 auth_req_packet *p = (auth_req_packet *) pkt;
876 875
877 slog (L_TRACE, "<<%d PT_AUTH(%d)", conf->id, p->subtype); 876 slog (L_TRACE, "<<%d PT_AUTH_REQ(%d)", conf->id, p->initiate);
878 877
879 if (p->chk_config ()
880 && !strncmp (p->magic, MAGIC, 8)) 878 if (p->chk_config () && !strncmp (p->magic, MAGIC, 8))
881 { 879 {
882 if (p->prot_minor != PROTOCOL_MINOR) 880 if (p->prot_minor != PROTOCOL_MINOR)
883 slog (L_INFO, _("protocol minor version mismatch: ours is %d, %s's is %d."), 881 slog (L_INFO, _("protocol minor version mismatch: ours is %d, %s's is %d."),
884 PROTOCOL_MINOR, conf->nodename, p->prot_minor); 882 PROTOCOL_MINOR, conf->nodename, p->prot_minor);
885 883
886 if (p->subtype == AUTH_INIT) 884 if (p->initiate)
887 send_auth (AUTH_INITREPLY, ssa); 885 send_auth_request (ssa, false);
888 886
889 const rsachallenge *k = rsa_cache.private_decrypt (::conf.rsa_key, p->challenge); 887 rsachallenge k;
890 888
891 if (!k) 889 if (0 > RSA_private_decrypt (sizeof (p->encr),
890 (unsigned char *)&p->encr, (unsigned char *)&k,
891 ::conf.rsa_key, RSA_PKCS1_OAEP_PADDING))
892 slog (L_ERR, _("challenge from %s (%s) illegal or corrupted"),
893 conf->nodename, (const char *)sockinfo (ssa));
894 else
892 { 895 {
893 slog (L_ERR, _("challenge from %s (%s) illegal or corrupted"), 896 retry_cnt = 0;
894 conf->nodename, (const char *)sockinfo (ssa)); 897 establish_connection.set (NOW + 8); //? ;)
898 keepalive.reset ();
899 rekey.reset ();
900
901 delete ictx;
902 ictx = 0;
903
904 delete octx;
905
906 octx = new crypto_ctx (k, 1);
907 oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff;
908
909 send_auth_response (ssa, p->id, k);
910
895 break; 911 break;
896 } 912 }
913 }
914 }
897 915
898 retry_cnt = 0; 916 send_reset (ssa);
899 establish_connection.set (NOW + 8); //? ;) 917 break;
900 keepalive.reset ();
901 rekey.reset ();
902 918
903 switch (p->subtype) 919 case vpn_packet::PT_AUTH_RES:
920 {
921 auth_res_packet *p = (auth_res_packet *) pkt;
922
923 slog (L_TRACE, "<<%d PT_AUTH_RES", conf->id);
924
925 if (p->chk_config ())
926 {
927 if (p->prot_minor != PROTOCOL_MINOR)
928 slog (L_INFO, _("protocol minor version mismatch: ours is %d, %s's is %d."),
929 PROTOCOL_MINOR, conf->nodename, p->prot_minor);
930
931 rsachallenge chg;
932
933 if (!rsa_cache.find (p->id, chg))
934 slog (L_ERR, _("unrequested auth response from %s (%s)"),
935 conf->nodename, (const char *)sockinfo (ssa));
936 else
904 { 937 {
905 case AUTH_INIT: 938 rsaresponse h;
906 case AUTH_INITREPLY:
907 delete ictx;
908 ictx = 0;
909 939
910 delete octx; 940 rsa_hash (chg, h);
911 941
912 octx = new crypto_ctx (*k, 1); 942 if (!memcmp ((u8 *)&h, (u8 *)p->response, sizeof h))
913 oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff;
914
915 send_auth (AUTH_REPLY, ssa, k);
916 break;
917
918 case AUTH_REPLY:
919
920 if (!memcmp ((u8 *)gen_challenge (seqrand, ssa), (u8 *)k, sizeof (rsachallenge)))
921 { 943 {
922 delete ictx; 944 delete ictx;
923 945
924 ictx = new crypto_ctx (*k, 0); 946 ictx = new crypto_ctx (chg, 0);
925 iseqno.reset (ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid 947 iseqno.reset (ntohl (*(u32 *)&chg[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid
926 948
927 sa = *ssa; 949 sa = *ssa;
928 950
929 rekey.set (NOW + ::conf.rekey); 951 rekey.set (NOW + ::conf.rekey);
930 keepalive.set (NOW + ::conf.keepalive); 952 keepalive.set (NOW + ::conf.keepalive);
… …
940 962
941 slog (L_INFO, _("connection to %d (%s %s) established"), 963 slog (L_INFO, _("connection to %d (%s %s) established"),
942 conf->id, conf->nodename, (const char *)sockinfo (ssa)); 964 conf->id, conf->nodename, (const char *)sockinfo (ssa));
943 965
944 if (::conf.script_node_up) 966 if (::conf.script_node_up)
945 run_script (this, &connection::script_node_up, false); 967 run_script (run_script_cb (this, &connection::script_node_up), false);
968
969 break;
946 } 970 }
947 else 971 else
948 slog (L_ERR, _("sent and received challenge do not match with (%s %s))"), 972 slog (L_ERR, _("sent and received challenge do not match with (%s %s))"),
949 conf->nodename, (const char *)sockinfo (ssa)); 973 conf->nodename, (const char *)sockinfo (ssa));
950
951 break;
952 default:
953 slog (L_ERR, _("authentification illegal subtype error (%s %s)"),
954 conf->nodename, (const char *)sockinfo (ssa));
955 break;
956 } 974 }
957 } 975 }
958 else
959 send_reset (ssa);
960
961 break;
962 } 976 }
977
978 send_reset (ssa);
979 break;
963 980
964 case vpn_packet::PT_DATA_COMPRESSED: 981 case vpn_packet::PT_DATA_COMPRESSED:
965#if !ENABLE_COMPRESSION 982#if !ENABLE_COMPRESSION
966 send_reset (ssa); 983 send_reset (ssa);
967 break; 984 break;
968#endif 985#endif
986
969 case vpn_packet::PT_DATA_UNCOMPRESSED: 987 case vpn_packet::PT_DATA_UNCOMPRESSED:
970 988
971 if (ictx && octx) 989 if (ictx && octx)
972 { 990 {
973 vpndata_packet *p = (vpndata_packet *)pkt; 991 vpndata_packet *p = (vpndata_packet *)pkt;
… …
1066 connection *c = vpn->conns[p->id - 1]; 1084 connection *c = vpn->conns[p->id - 1];
1067 1085
1068 slog (L_TRACE, "<<%d PT_CONNECT_INFO(%d,%s) (%d)", 1086 slog (L_TRACE, "<<%d PT_CONNECT_INFO(%d,%s) (%d)",
1069 conf->id, p->id, (const char *)p->si, !c->ictx && !c->octx); 1087 conf->id, p->id, (const char *)p->si, !c->ictx && !c->octx);
1070 1088
1071 c->send_auth (AUTH_INIT, p->si.sa ()); 1089 c->send_auth_request (p->si.sa (), true);
1072 } 1090 }
1091
1073 break; 1092 break;
1074 1093
1075 default: 1094 default:
1076 send_reset (ssa); 1095 send_reset (ssa);
1077 break; 1096 break;
1097
1078 } 1098 }
1079} 1099}
1080 1100
1081void connection::keepalive_cb (tstamp &ts) 1101void connection::keepalive_cb (tstamp &ts)
1082{ 1102{
… …
1109 delete p; 1129 delete p;
1110} 1130}
1111 1131
1112void connection::script_node () 1132void connection::script_node ()
1113{ 1133{
1114 vpn->script_if_up (); 1134 vpn->script_if_up (0);
1115 1135
1116 char *env; 1136 char *env;
1117 asprintf (&env, "DESTID=%d", conf->id); 1137 asprintf (&env, "DESTID=%d", conf->id);
1118 putenv (env); 1138 putenv (env);
1119 asprintf (&env, "DESTNODE=%s", conf->nodename); 1139 asprintf (&env, "DESTNODE=%s", conf->nodename);
… …
1122 putenv (env); 1142 putenv (env);
1123 asprintf (&env, "DESTPORT=%d", ntohs (sa.sin_port)); 1143 asprintf (&env, "DESTPORT=%d", ntohs (sa.sin_port));
1124 putenv (env); 1144 putenv (env);
1125} 1145}
1126 1146
1127const char *connection::script_node_up () 1147const char *connection::script_node_up (int)
1128{ 1148{
1129 script_node (); 1149 script_node ();
1130 1150
1131 putenv ("STATE=up"); 1151 putenv ("STATE=up");
1132 1152
1133 return ::conf.script_node_up ? ::conf.script_node_up : "node-up"; 1153 return ::conf.script_node_up ? ::conf.script_node_up : "node-up";
1134} 1154}
1135 1155
1136const char *connection::script_node_down () 1156const char *connection::script_node_down (int)
1137{ 1157{
1138 script_node (); 1158 script_node ();
1139 1159
1140 putenv ("STATE=down"); 1160 putenv ("STATE=down");
1141 1161
… …
1160 shutdown (); 1180 shutdown ();
1161} 1181}
1162 1182
1163///////////////////////////////////////////////////////////////////////////// 1183/////////////////////////////////////////////////////////////////////////////
1164 1184
1165const char *vpn::script_if_up () 1185const char *vpn::script_if_up (int)
1166{ 1186{
1167 // the tunnel device mtu should be the physical mtu - overhead 1187 // the tunnel device mtu should be the physical mtu - overhead
1168 // the tricky part is rounding to the cipher key blocksize 1188 // the tricky part is rounding to the cipher key blocksize
1169 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - UDP_OVERHEAD; 1189 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
1170 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion 1190 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
1171 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round 1191 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
1172 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again 1192 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
1173 1193
1174 char *env; 1194 char *env;
… …
1228 { 1248 {
1229 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname); 1249 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
1230 exit (1); 1250 exit (1);
1231 } 1251 }
1232 1252
1233 run_script (this, &vpn::script_if_up, true); 1253 run_script (run_script_cb (this, &vpn::script_if_up), true);
1234 1254
1235 vpn_ev_watcher.start (tap->fd, POLLIN); 1255 vpn_ev_watcher.start (tap->fd, POLLIN);
1236 1256
1237 reconnect_all (); 1257 reconnect_all ();
1238 1258

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