f26d5c33 |
1 | #include <stdio.h> |
2 | #include <stdlib.h> |
3 | |
4 | #include "putty.h" |
5 | #include "ssh.h" |
6 | |
7 | #ifndef FALSE |
8 | #define FALSE 0 |
9 | #endif |
10 | #ifndef TRUE |
11 | #define TRUE 1 |
12 | #endif |
13 | |
14 | #define GET_32BIT_LSB_FIRST(cp) \ |
15 | (((unsigned long)(unsigned char)(cp)[0]) | \ |
16 | ((unsigned long)(unsigned char)(cp)[1] << 8) | \ |
17 | ((unsigned long)(unsigned char)(cp)[2] << 16) | \ |
18 | ((unsigned long)(unsigned char)(cp)[3] << 24)) |
19 | |
20 | #define PUT_32BIT_LSB_FIRST(cp, value) ( \ |
21 | (cp)[0] = (value), \ |
22 | (cp)[1] = (value) >> 8, \ |
23 | (cp)[2] = (value) >> 16, \ |
24 | (cp)[3] = (value) >> 24 ) |
25 | |
26 | #define GET_16BIT_LSB_FIRST(cp) \ |
27 | (((unsigned long)(unsigned char)(cp)[0]) | \ |
28 | ((unsigned long)(unsigned char)(cp)[1] << 8)) |
29 | |
30 | #define PUT_16BIT_LSB_FIRST(cp, value) ( \ |
31 | (cp)[0] = (value), \ |
32 | (cp)[1] = (value) >> 8 ) |
33 | |
34 | #define GET_32BIT_MSB_FIRST(cp) \ |
35 | (((unsigned long)(unsigned char)(cp)[0] << 24) | \ |
36 | ((unsigned long)(unsigned char)(cp)[1] << 16) | \ |
37 | ((unsigned long)(unsigned char)(cp)[2] << 8) | \ |
38 | ((unsigned long)(unsigned char)(cp)[3])) |
39 | |
40 | #define PUT_32BIT_MSB_FIRST(cp, value) ( \ |
41 | (cp)[0] = (value) >> 24, \ |
42 | (cp)[1] = (value) >> 16, \ |
43 | (cp)[2] = (value) >> 8, \ |
44 | (cp)[3] = (value) ) |
45 | |
46 | #define GET_16BIT_MSB_FIRST(cp) \ |
47 | (((unsigned long)(unsigned char)(cp)[0] << 8) | \ |
48 | ((unsigned long)(unsigned char)(cp)[1])) |
49 | |
50 | #define PUT_16BIT_MSB_FIRST(cp, value) ( \ |
51 | (cp)[0] = (value) >> 8, \ |
52 | (cp)[1] = (value) ) |
53 | |
f26d5c33 |
54 | struct PFwdPrivate { |
c85623f9 |
55 | const struct plug_function_table *fn; |
f26d5c33 |
56 | /* the above variable absolutely *must* be the first in this structure */ |
57 | void *c; /* (channel) data used by ssh.c */ |
6b78788a |
58 | void *backhandle; /* instance of SSH backend itself */ |
59 | /* Note that backhandle need not be filled in if c is non-NULL */ |
f26d5c33 |
60 | Socket s; |
5471d09a |
61 | int throttled, throttle_override; |
f26d5c33 |
62 | int ready; |
820ebe3b |
63 | /* |
64 | * `dynamic' does double duty. It's set to 0 for an ordinary |
65 | * forwarded port, and nonzero for SOCKS-style dynamic port |
66 | * forwarding; but it also represents the state of the SOCKS |
67 | * exchange. |
68 | */ |
69 | int dynamic; |
70 | /* |
71 | * `hostname' and `port' are the real hostname and port, once |
72 | * we know what we're connecting to; they're unused for this |
73 | * purpose while conducting a local SOCKS exchange, which means |
74 | * we can also use them as a buffer and pointer for reading |
75 | * data from the SOCKS client. |
76 | */ |
fab893b6 |
77 | char hostname[256+8]; |
820ebe3b |
78 | int port; |
79 | /* |
80 | * When doing dynamic port forwarding, we can receive |
81 | * connection data before we are actually able to send it; so |
82 | * we may have to temporarily hold some in a dynamically |
83 | * allocated buffer here. |
84 | */ |
85 | void *buffer; |
86 | int buflen; |
f26d5c33 |
87 | }; |
88 | |
cbe2d68f |
89 | static int pfd_closing(Plug plug, const char *error_msg, int error_code, |
f26d5c33 |
90 | int calling_back) |
91 | { |
92 | struct PFwdPrivate *pr = (struct PFwdPrivate *) plug; |
93 | |
94 | /* |
95 | * We have no way to communicate down the forwarded connection, |
96 | * so if an error occurred on the socket, we just ignore it |
97 | * and treat it like a proper close. |
98 | */ |
820ebe3b |
99 | if (pr->c) |
100 | sshfwd_close(pr->c); |
f26d5c33 |
101 | pfd_close(pr->s); |
102 | return 1; |
103 | } |
104 | |
105 | static int pfd_receive(Plug plug, int urgent, char *data, int len) |
106 | { |
107 | struct PFwdPrivate *pr = (struct PFwdPrivate *) plug; |
820ebe3b |
108 | if (pr->dynamic) { |
109 | while (len--) { |
b8a98e25 |
110 | /* |
111 | * Throughout SOCKS negotiation, "hostname" is re-used as a |
112 | * random protocol buffer with "port" storing the length. |
113 | */ |
820ebe3b |
114 | if (pr->port >= lenof(pr->hostname)) { |
04df1251 |
115 | /* Request too long. */ |
820ebe3b |
116 | if ((pr->dynamic >> 12) == 4) { |
117 | /* Send back a SOCKS 4 error before closing. */ |
118 | char data[8]; |
119 | memset(data, 0, sizeof(data)); |
120 | data[1] = 91; /* generic `request rejected' */ |
121 | sk_write(pr->s, data, 8); |
122 | } |
123 | pfd_close(pr->s); |
124 | return 1; |
125 | } |
126 | pr->hostname[pr->port++] = *data++; |
127 | |
128 | /* |
129 | * Now check what's in the buffer to see if it's a |
130 | * valid and complete message in the SOCKS exchange. |
131 | */ |
132 | if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) && |
133 | pr->hostname[0] == 4) { |
134 | /* |
135 | * SOCKS 4. |
136 | */ |
137 | if (pr->dynamic == 1) |
138 | pr->dynamic = 0x4000; |
139 | if (pr->port < 2) continue;/* don't have command code yet */ |
140 | if (pr->hostname[1] != 1) { |
b8a98e25 |
141 | /* Not CONNECT. */ |
820ebe3b |
142 | /* Send back a SOCKS 4 error before closing. */ |
143 | char data[8]; |
144 | memset(data, 0, sizeof(data)); |
145 | data[1] = 91; /* generic `request rejected' */ |
146 | sk_write(pr->s, data, 8); |
147 | pfd_close(pr->s); |
148 | return 1; |
149 | } |
b8a98e25 |
150 | if (pr->port <= 8) continue; /* haven't started user/hostname */ |
820ebe3b |
151 | if (pr->hostname[pr->port-1] != 0) |
b8a98e25 |
152 | continue; /* haven't _finished_ user/hostname */ |
820ebe3b |
153 | /* |
154 | * Now we have a full SOCKS 4 request. Check it to |
155 | * see if it's a SOCKS 4A request. |
156 | */ |
157 | if (pr->hostname[4] == 0 && pr->hostname[5] == 0 && |
158 | pr->hostname[6] == 0 && pr->hostname[7] != 0) { |
159 | /* |
160 | * It's SOCKS 4A. So if we haven't yet |
161 | * collected the host name, we should continue |
162 | * waiting for data in order to do so; if we |
163 | * have, we can go ahead. |
164 | */ |
165 | int len; |
166 | if (pr->dynamic == 0x4000) { |
167 | pr->dynamic = 0x4001; |
fab893b6 |
168 | pr->port = 8; /* reset buffer to overwrite name */ |
820ebe3b |
169 | continue; |
170 | } |
171 | pr->hostname[0] = 0; /* reply version code */ |
172 | pr->hostname[1] = 90; /* request granted */ |
173 | sk_write(pr->s, pr->hostname, 8); |
b8a98e25 |
174 | len= pr->port - 8; |
820ebe3b |
175 | pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2); |
fab893b6 |
176 | memmove(pr->hostname, pr->hostname + 8, len); |
820ebe3b |
177 | goto connect; |
178 | } else { |
179 | /* |
180 | * It's SOCKS 4, which means we should format |
181 | * the IP address into the hostname string and |
182 | * then just go. |
183 | */ |
184 | pr->hostname[0] = 0; /* reply version code */ |
185 | pr->hostname[1] = 90; /* request granted */ |
186 | sk_write(pr->s, pr->hostname, 8); |
187 | pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2); |
188 | sprintf(pr->hostname, "%d.%d.%d.%d", |
189 | (unsigned char)pr->hostname[4], |
190 | (unsigned char)pr->hostname[5], |
191 | (unsigned char)pr->hostname[6], |
192 | (unsigned char)pr->hostname[7]); |
193 | goto connect; |
194 | } |
195 | } |
196 | |
197 | if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) && |
198 | pr->hostname[0] == 5) { |
199 | /* |
200 | * SOCKS 5. |
201 | */ |
202 | if (pr->dynamic == 1) |
203 | pr->dynamic = 0x5000; |
204 | |
205 | if (pr->dynamic == 0x5000) { |
206 | int i, method; |
207 | char data[2]; |
208 | /* |
209 | * We're receiving a set of method identifiers. |
210 | */ |
211 | if (pr->port < 2) continue;/* no method count yet */ |
212 | if (pr->port < 2 + (unsigned char)pr->hostname[1]) |
213 | continue; /* no methods yet */ |
214 | method = 0xFF; /* invalid */ |
215 | for (i = 0; i < (unsigned char)pr->hostname[1]; i++) |
216 | if (pr->hostname[2+i] == 0) { |
217 | method = 0;/* no auth */ |
218 | break; |
219 | } |
220 | data[0] = 5; |
221 | data[1] = method; |
222 | sk_write(pr->s, data, 2); |
223 | pr->dynamic = 0x5001; |
224 | pr->port = 0; /* re-empty the buffer */ |
225 | continue; |
226 | } |
227 | |
228 | if (pr->dynamic == 0x5001) { |
04df1251 |
229 | /* |
230 | * We're receiving a SOCKS request. |
231 | */ |
232 | unsigned char reply[10]; /* SOCKS5 atyp=1 reply */ |
4797387c |
233 | int atype, alen = 0; |
04df1251 |
234 | |
235 | /* |
236 | * Pre-fill reply packet. |
237 | * In all cases, we set BND.{HOST,ADDR} to 0.0.0.0:0 |
238 | * (atyp=1) in the reply; if we succeed, we don't know |
239 | * the right answers, and if we fail, they should be |
240 | * ignored. |
241 | */ |
242 | memset(reply, 0, lenof(reply)); |
243 | reply[0] = 5; /* VER */ |
244 | reply[3] = 1; /* ATYP = 1 (IPv4, 0.0.0.0:0) */ |
245 | |
820ebe3b |
246 | if (pr->port < 6) continue; |
247 | atype = (unsigned char)pr->hostname[3]; |
248 | if (atype == 1) /* IPv4 address */ |
249 | alen = 4; |
250 | if (atype == 4) /* IPv6 address */ |
251 | alen = 16; |
252 | if (atype == 3) /* domain name has leading length */ |
253 | alen = 1 + (unsigned char)pr->hostname[4]; |
254 | if (pr->port < 6 + alen) continue; |
255 | if (pr->hostname[1] != 1 || pr->hostname[2] != 0) { |
04df1251 |
256 | /* Not CONNECT or reserved field nonzero - error */ |
257 | reply[1] = 1; /* generic failure */ |
258 | sk_write(pr->s, reply, lenof(reply)); |
820ebe3b |
259 | pfd_close(pr->s); |
260 | return 1; |
261 | } |
262 | /* |
263 | * Now we have a viable connect request. Switch |
264 | * on atype. |
265 | */ |
266 | pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen); |
267 | if (atype == 1) { |
04df1251 |
268 | /* REP=0 (success) already */ |
269 | sk_write(pr->s, reply, lenof(reply)); |
820ebe3b |
270 | sprintf(pr->hostname, "%d.%d.%d.%d", |
271 | (unsigned char)pr->hostname[4], |
272 | (unsigned char)pr->hostname[5], |
273 | (unsigned char)pr->hostname[6], |
274 | (unsigned char)pr->hostname[7]); |
275 | goto connect; |
276 | } else if (atype == 3) { |
04df1251 |
277 | /* REP=0 (success) already */ |
278 | sk_write(pr->s, reply, lenof(reply)); |
820ebe3b |
279 | memmove(pr->hostname, pr->hostname + 5, alen-1); |
280 | pr->hostname[alen-1] = '\0'; |
281 | goto connect; |
282 | } else { |
283 | /* |
284 | * Unknown address type. (FIXME: support IPv6!) |
285 | */ |
04df1251 |
286 | reply[1] = 8; /* atype not supported */ |
287 | sk_write(pr->s, reply, lenof(reply)); |
820ebe3b |
288 | pfd_close(pr->s); |
289 | return 1; |
290 | } |
291 | } |
292 | } |
293 | |
294 | /* |
295 | * If we get here without either having done `continue' |
296 | * or `goto connect', it must be because there is no |
297 | * sensible interpretation of what's in our buffer. So |
298 | * close the connection rudely. |
299 | */ |
300 | pfd_close(pr->s); |
301 | return 1; |
302 | } |
303 | return 1; |
304 | |
305 | /* |
306 | * We come here when we're ready to make an actual |
307 | * connection. |
308 | */ |
309 | connect: |
310 | |
311 | pr->c = new_sock_channel(pr->backhandle, pr->s); |
312 | if (pr->c == NULL) { |
313 | pfd_close(pr->s); |
314 | return 1; |
315 | } else { |
316 | /* asks to forward to the specified host/port for this */ |
317 | ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding"); |
318 | } |
319 | pr->dynamic = 0; |
320 | |
321 | /* |
322 | * Now freeze the socket until the SSH server confirms the |
323 | * connection. |
324 | */ |
325 | sk_set_frozen(pr->s, 1); |
326 | /* |
327 | * If there's any data remaining in our current buffer, |
328 | * save it to be sent on pfd_confirm(). |
329 | */ |
330 | if (len > 0) { |
331 | pr->buffer = snewn(len, char); |
332 | memcpy(pr->buffer, data, len); |
333 | pr->buflen = len; |
334 | } |
335 | } |
5471d09a |
336 | if (pr->ready) { |
337 | if (sshfwd_write(pr->c, data, len) > 0) { |
338 | pr->throttled = 1; |
339 | sk_set_frozen(pr->s, 1); |
340 | } |
341 | } |
f26d5c33 |
342 | return 1; |
343 | } |
344 | |
5471d09a |
345 | static void pfd_sent(Plug plug, int bufsize) |
346 | { |
347 | struct PFwdPrivate *pr = (struct PFwdPrivate *) plug; |
348 | |
820ebe3b |
349 | if (pr->c) |
350 | sshfwd_unthrottle(pr->c, bufsize); |
5471d09a |
351 | } |
352 | |
f26d5c33 |
353 | /* |
354 | * Called when receiving a PORT OPEN from the server |
355 | */ |
cbe2d68f |
356 | const char *pfd_newconnect(Socket *s, char *hostname, int port, |
357 | void *c, const Config *cfg) |
f26d5c33 |
358 | { |
c85623f9 |
359 | static const struct plug_function_table fn_table = { |
f26d5c33 |
360 | pfd_closing, |
361 | pfd_receive, |
5471d09a |
362 | pfd_sent, |
f26d5c33 |
363 | NULL |
364 | }; |
365 | |
366 | SockAddr addr; |
cbe2d68f |
367 | const char *err; |
368 | char *dummy_realhost; |
f26d5c33 |
369 | struct PFwdPrivate *pr; |
370 | |
371 | /* |
372 | * Try to find host. |
373 | */ |
e8fa8f62 |
374 | addr = name_lookup(hostname, port, &dummy_realhost, cfg); |
f85e6f6e |
375 | if ((err = sk_addr_error(addr)) != NULL) { |
376 | sk_addr_free(addr); |
f26d5c33 |
377 | return err; |
f85e6f6e |
378 | } |
f26d5c33 |
379 | |
380 | /* |
381 | * Open socket. |
382 | */ |
3d88e64d |
383 | pr = snew(struct PFwdPrivate); |
820ebe3b |
384 | pr->buffer = NULL; |
f26d5c33 |
385 | pr->fn = &fn_table; |
5471d09a |
386 | pr->throttled = pr->throttle_override = 0; |
f26d5c33 |
387 | pr->ready = 1; |
388 | pr->c = c; |
6b78788a |
389 | pr->backhandle = NULL; /* we shouldn't need this */ |
4b42e4f6 |
390 | pr->dynamic = 0; |
f26d5c33 |
391 | |
e8fa8f62 |
392 | pr->s = *s = new_connection(addr, dummy_realhost, port, |
393 | 0, 1, 0, (Plug) pr, cfg); |
808c3834 |
394 | if ((err = sk_socket_error(*s)) != NULL) { |
f26d5c33 |
395 | sfree(pr); |
396 | return err; |
397 | } |
398 | |
399 | sk_set_private_ptr(*s, pr); |
f26d5c33 |
400 | return NULL; |
401 | } |
402 | |
403 | /* |
404 | called when someone connects to the local port |
405 | */ |
406 | |
f7f9fb5c |
407 | static int pfd_accepting(Plug p, OSSocket sock) |
f26d5c33 |
408 | { |
c85623f9 |
409 | static const struct plug_function_table fn_table = { |
f26d5c33 |
410 | pfd_closing, |
411 | pfd_receive, |
5471d09a |
412 | pfd_sent, |
f26d5c33 |
413 | NULL |
414 | }; |
415 | struct PFwdPrivate *pr, *org; |
f26d5c33 |
416 | Socket s; |
cbe2d68f |
417 | const char *err; |
f26d5c33 |
418 | |
f26d5c33 |
419 | org = (struct PFwdPrivate *)p; |
3d88e64d |
420 | pr = snew(struct PFwdPrivate); |
820ebe3b |
421 | pr->buffer = NULL; |
f26d5c33 |
422 | pr->fn = &fn_table; |
423 | |
424 | pr->c = NULL; |
6b78788a |
425 | pr->backhandle = org->backhandle; |
f26d5c33 |
426 | |
427 | pr->s = s = sk_register(sock, (Plug) pr); |
808c3834 |
428 | if ((err = sk_socket_error(s)) != NULL) { |
f26d5c33 |
429 | sfree(pr); |
430 | return err != NULL; |
431 | } |
432 | |
820ebe3b |
433 | sk_set_private_ptr(s, pr); |
f26d5c33 |
434 | |
5471d09a |
435 | pr->throttled = pr->throttle_override = 0; |
f26d5c33 |
436 | pr->ready = 0; |
f26d5c33 |
437 | |
820ebe3b |
438 | if (org->dynamic) { |
439 | pr->dynamic = 1; |
b8a98e25 |
440 | pr->port = 0; /* "hostname" buffer is so far empty */ |
820ebe3b |
441 | sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */ |
f26d5c33 |
442 | } else { |
4b42e4f6 |
443 | pr->dynamic = 0; |
820ebe3b |
444 | strcpy(pr->hostname, org->hostname); |
445 | pr->port = org->port; |
446 | pr->c = new_sock_channel(org->backhandle, s); |
447 | |
448 | if (pr->c == NULL) { |
449 | sfree(pr); |
450 | return 1; |
451 | } else { |
452 | /* asks to forward to the specified host/port for this */ |
453 | ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding"); |
454 | } |
f26d5c33 |
455 | } |
456 | |
457 | return 0; |
458 | } |
459 | |
460 | |
461 | /* Add a new forwarding from port -> desthost:destport |
6ee9b735 |
462 | sets up a listener on the local machine on (srcaddr:)port |
f26d5c33 |
463 | */ |
cbe2d68f |
464 | const char *pfd_addforward(char *desthost, int destport, char *srcaddr, |
465 | int port, void *backhandle, const Config *cfg) |
f26d5c33 |
466 | { |
c85623f9 |
467 | static const struct plug_function_table fn_table = { |
f26d5c33 |
468 | pfd_closing, |
5471d09a |
469 | pfd_receive, /* should not happen... */ |
470 | pfd_sent, /* also should not happen */ |
f26d5c33 |
471 | pfd_accepting |
472 | }; |
473 | |
cbe2d68f |
474 | const char *err; |
f26d5c33 |
475 | struct PFwdPrivate *pr; |
476 | Socket s; |
477 | |
478 | /* |
479 | * Open socket. |
480 | */ |
3d88e64d |
481 | pr = snew(struct PFwdPrivate); |
820ebe3b |
482 | pr->buffer = NULL; |
f26d5c33 |
483 | pr->fn = &fn_table; |
484 | pr->c = NULL; |
820ebe3b |
485 | if (desthost) { |
486 | strcpy(pr->hostname, desthost); |
487 | pr->port = destport; |
488 | pr->dynamic = 0; |
489 | } else |
490 | pr->dynamic = 1; |
5471d09a |
491 | pr->throttled = pr->throttle_override = 0; |
f26d5c33 |
492 | pr->ready = 0; |
6b78788a |
493 | pr->backhandle = backhandle; |
f26d5c33 |
494 | |
e8fa8f62 |
495 | pr->s = s = new_listener(srcaddr, port, (Plug) pr, |
496 | !cfg->lport_acceptall, cfg); |
808c3834 |
497 | if ((err = sk_socket_error(s)) != NULL) { |
f26d5c33 |
498 | sfree(pr); |
499 | return err; |
500 | } |
501 | |
502 | sk_set_private_ptr(s, pr); |
503 | |
504 | return NULL; |
505 | } |
506 | |
507 | void pfd_close(Socket s) |
508 | { |
509 | struct PFwdPrivate *pr; |
510 | |
511 | if (!s) |
512 | return; |
513 | |
514 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
515 | |
820ebe3b |
516 | sfree(pr->buffer); |
f26d5c33 |
517 | sfree(pr); |
518 | |
519 | sk_close(s); |
520 | } |
521 | |
5471d09a |
522 | void pfd_unthrottle(Socket s) |
523 | { |
524 | struct PFwdPrivate *pr; |
525 | if (!s) |
526 | return; |
527 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
528 | |
529 | pr->throttled = 0; |
530 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
531 | } |
532 | |
533 | void pfd_override_throttle(Socket s, int enable) |
534 | { |
535 | struct PFwdPrivate *pr; |
536 | if (!s) |
537 | return; |
538 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
539 | |
540 | pr->throttle_override = enable; |
541 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
542 | } |
543 | |
f26d5c33 |
544 | /* |
545 | * Called to send data down the raw connection. |
546 | */ |
5471d09a |
547 | int pfd_send(Socket s, char *data, int len) |
f26d5c33 |
548 | { |
f26d5c33 |
549 | if (s == NULL) |
5471d09a |
550 | return 0; |
551 | return sk_write(s, data, len); |
f26d5c33 |
552 | } |
553 | |
554 | |
555 | void pfd_confirm(Socket s) |
556 | { |
5f2e19fc |
557 | struct PFwdPrivate *pr; |
f26d5c33 |
558 | |
559 | if (s == NULL) |
560 | return; |
561 | |
5f2e19fc |
562 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
f26d5c33 |
563 | pr->ready = 1; |
564 | sk_set_frozen(s, 0); |
565 | sk_write(s, NULL, 0); |
820ebe3b |
566 | if (pr->buffer) { |
567 | sshfwd_write(pr->c, pr->buffer, pr->buflen); |
568 | sfree(pr->buffer); |
569 | pr->buffer = NULL; |
570 | } |
f26d5c33 |
571 | } |