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--) { |
110 | if (pr->port >= lenof(pr->hostname)) { |
111 | if ((pr->dynamic >> 12) == 4) { |
112 | /* Send back a SOCKS 4 error before closing. */ |
113 | char data[8]; |
114 | memset(data, 0, sizeof(data)); |
115 | data[1] = 91; /* generic `request rejected' */ |
116 | sk_write(pr->s, data, 8); |
117 | } |
118 | pfd_close(pr->s); |
119 | return 1; |
120 | } |
121 | pr->hostname[pr->port++] = *data++; |
122 | |
123 | /* |
124 | * Now check what's in the buffer to see if it's a |
125 | * valid and complete message in the SOCKS exchange. |
126 | */ |
127 | if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 4) && |
128 | pr->hostname[0] == 4) { |
129 | /* |
130 | * SOCKS 4. |
131 | */ |
132 | if (pr->dynamic == 1) |
133 | pr->dynamic = 0x4000; |
134 | if (pr->port < 2) continue;/* don't have command code yet */ |
135 | if (pr->hostname[1] != 1) { |
136 | /* Send back a SOCKS 4 error before closing. */ |
137 | char data[8]; |
138 | memset(data, 0, sizeof(data)); |
139 | data[1] = 91; /* generic `request rejected' */ |
140 | sk_write(pr->s, data, 8); |
141 | pfd_close(pr->s); |
142 | return 1; |
143 | } |
144 | if (pr->port < 8) continue; /* haven't started username */ |
145 | if (pr->hostname[pr->port-1] != 0) |
146 | continue; /* haven't _finished_ username */ |
147 | /* |
148 | * Now we have a full SOCKS 4 request. Check it to |
149 | * see if it's a SOCKS 4A request. |
150 | */ |
151 | if (pr->hostname[4] == 0 && pr->hostname[5] == 0 && |
152 | pr->hostname[6] == 0 && pr->hostname[7] != 0) { |
153 | /* |
154 | * It's SOCKS 4A. So if we haven't yet |
155 | * collected the host name, we should continue |
156 | * waiting for data in order to do so; if we |
157 | * have, we can go ahead. |
158 | */ |
159 | int len; |
160 | if (pr->dynamic == 0x4000) { |
161 | pr->dynamic = 0x4001; |
fab893b6 |
162 | pr->port = 8; /* reset buffer to overwrite name */ |
820ebe3b |
163 | continue; |
164 | } |
165 | pr->hostname[0] = 0; /* reply version code */ |
166 | pr->hostname[1] = 90; /* request granted */ |
167 | sk_write(pr->s, pr->hostname, 8); |
fab893b6 |
168 | len= pr->port; |
820ebe3b |
169 | pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2); |
fab893b6 |
170 | memmove(pr->hostname, pr->hostname + 8, len); |
820ebe3b |
171 | goto connect; |
172 | } else { |
173 | /* |
174 | * It's SOCKS 4, which means we should format |
175 | * the IP address into the hostname string and |
176 | * then just go. |
177 | */ |
178 | pr->hostname[0] = 0; /* reply version code */ |
179 | pr->hostname[1] = 90; /* request granted */ |
180 | sk_write(pr->s, pr->hostname, 8); |
181 | pr->port = GET_16BIT_MSB_FIRST(pr->hostname+2); |
182 | sprintf(pr->hostname, "%d.%d.%d.%d", |
183 | (unsigned char)pr->hostname[4], |
184 | (unsigned char)pr->hostname[5], |
185 | (unsigned char)pr->hostname[6], |
186 | (unsigned char)pr->hostname[7]); |
187 | goto connect; |
188 | } |
189 | } |
190 | |
191 | if ((pr->dynamic == 1 || (pr->dynamic >> 12) == 5) && |
192 | pr->hostname[0] == 5) { |
193 | /* |
194 | * SOCKS 5. |
195 | */ |
196 | if (pr->dynamic == 1) |
197 | pr->dynamic = 0x5000; |
198 | |
199 | if (pr->dynamic == 0x5000) { |
200 | int i, method; |
201 | char data[2]; |
202 | /* |
203 | * We're receiving a set of method identifiers. |
204 | */ |
205 | if (pr->port < 2) continue;/* no method count yet */ |
206 | if (pr->port < 2 + (unsigned char)pr->hostname[1]) |
207 | continue; /* no methods yet */ |
208 | method = 0xFF; /* invalid */ |
209 | for (i = 0; i < (unsigned char)pr->hostname[1]; i++) |
210 | if (pr->hostname[2+i] == 0) { |
211 | method = 0;/* no auth */ |
212 | break; |
213 | } |
214 | data[0] = 5; |
215 | data[1] = method; |
216 | sk_write(pr->s, data, 2); |
217 | pr->dynamic = 0x5001; |
218 | pr->port = 0; /* re-empty the buffer */ |
219 | continue; |
220 | } |
221 | |
222 | if (pr->dynamic == 0x5001) { |
4797387c |
223 | int atype, alen = 0; |
820ebe3b |
224 | if (pr->port < 6) continue; |
225 | atype = (unsigned char)pr->hostname[3]; |
226 | if (atype == 1) /* IPv4 address */ |
227 | alen = 4; |
228 | if (atype == 4) /* IPv6 address */ |
229 | alen = 16; |
230 | if (atype == 3) /* domain name has leading length */ |
231 | alen = 1 + (unsigned char)pr->hostname[4]; |
232 | if (pr->port < 6 + alen) continue; |
233 | if (pr->hostname[1] != 1 || pr->hostname[2] != 0) { |
234 | pr->hostname[1] = 1; /* generic failure */ |
235 | pr->hostname[2] = 0; /* reserved */ |
236 | sk_write(pr->s, pr->hostname, pr->port); |
237 | pfd_close(pr->s); |
238 | return 1; |
239 | } |
240 | /* |
241 | * Now we have a viable connect request. Switch |
242 | * on atype. |
243 | */ |
244 | pr->port = GET_16BIT_MSB_FIRST(pr->hostname+4+alen); |
245 | if (atype == 1) { |
246 | pr->hostname[1] = 0; /* succeeded */ |
247 | sk_write(pr->s, pr->hostname, alen + 6); |
248 | sprintf(pr->hostname, "%d.%d.%d.%d", |
249 | (unsigned char)pr->hostname[4], |
250 | (unsigned char)pr->hostname[5], |
251 | (unsigned char)pr->hostname[6], |
252 | (unsigned char)pr->hostname[7]); |
253 | goto connect; |
254 | } else if (atype == 3) { |
255 | pr->hostname[1] = 0; /* succeeded */ |
256 | sk_write(pr->s, pr->hostname, alen + 6); |
257 | memmove(pr->hostname, pr->hostname + 5, alen-1); |
258 | pr->hostname[alen-1] = '\0'; |
259 | goto connect; |
260 | } else { |
261 | /* |
262 | * Unknown address type. (FIXME: support IPv6!) |
263 | */ |
264 | pr->hostname[1] = 8; /* atype not supported */ |
265 | sk_write(pr->s, pr->hostname, pr->port); |
266 | pfd_close(pr->s); |
267 | return 1; |
268 | } |
269 | } |
270 | } |
271 | |
272 | /* |
273 | * If we get here without either having done `continue' |
274 | * or `goto connect', it must be because there is no |
275 | * sensible interpretation of what's in our buffer. So |
276 | * close the connection rudely. |
277 | */ |
278 | pfd_close(pr->s); |
279 | return 1; |
280 | } |
281 | return 1; |
282 | |
283 | /* |
284 | * We come here when we're ready to make an actual |
285 | * connection. |
286 | */ |
287 | connect: |
288 | |
289 | pr->c = new_sock_channel(pr->backhandle, pr->s); |
290 | if (pr->c == NULL) { |
291 | pfd_close(pr->s); |
292 | return 1; |
293 | } else { |
294 | /* asks to forward to the specified host/port for this */ |
295 | ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding"); |
296 | } |
297 | pr->dynamic = 0; |
298 | |
299 | /* |
300 | * Now freeze the socket until the SSH server confirms the |
301 | * connection. |
302 | */ |
303 | sk_set_frozen(pr->s, 1); |
304 | /* |
305 | * If there's any data remaining in our current buffer, |
306 | * save it to be sent on pfd_confirm(). |
307 | */ |
308 | if (len > 0) { |
309 | pr->buffer = snewn(len, char); |
310 | memcpy(pr->buffer, data, len); |
311 | pr->buflen = len; |
312 | } |
313 | } |
5471d09a |
314 | if (pr->ready) { |
315 | if (sshfwd_write(pr->c, data, len) > 0) { |
316 | pr->throttled = 1; |
317 | sk_set_frozen(pr->s, 1); |
318 | } |
319 | } |
f26d5c33 |
320 | return 1; |
321 | } |
322 | |
5471d09a |
323 | static void pfd_sent(Plug plug, int bufsize) |
324 | { |
325 | struct PFwdPrivate *pr = (struct PFwdPrivate *) plug; |
326 | |
820ebe3b |
327 | if (pr->c) |
328 | sshfwd_unthrottle(pr->c, bufsize); |
5471d09a |
329 | } |
330 | |
f26d5c33 |
331 | /* |
332 | * Called when receiving a PORT OPEN from the server |
333 | */ |
cbe2d68f |
334 | const char *pfd_newconnect(Socket *s, char *hostname, int port, |
335 | void *c, const Config *cfg) |
f26d5c33 |
336 | { |
c85623f9 |
337 | static const struct plug_function_table fn_table = { |
f26d5c33 |
338 | pfd_closing, |
339 | pfd_receive, |
5471d09a |
340 | pfd_sent, |
f26d5c33 |
341 | NULL |
342 | }; |
343 | |
344 | SockAddr addr; |
cbe2d68f |
345 | const char *err; |
346 | char *dummy_realhost; |
f26d5c33 |
347 | struct PFwdPrivate *pr; |
348 | |
349 | /* |
350 | * Try to find host. |
351 | */ |
e8fa8f62 |
352 | addr = name_lookup(hostname, port, &dummy_realhost, cfg); |
808c3834 |
353 | if ((err = sk_addr_error(addr)) != NULL) |
f26d5c33 |
354 | return err; |
355 | |
356 | /* |
357 | * Open socket. |
358 | */ |
3d88e64d |
359 | pr = snew(struct PFwdPrivate); |
820ebe3b |
360 | pr->buffer = NULL; |
f26d5c33 |
361 | pr->fn = &fn_table; |
5471d09a |
362 | pr->throttled = pr->throttle_override = 0; |
f26d5c33 |
363 | pr->ready = 1; |
364 | pr->c = c; |
6b78788a |
365 | pr->backhandle = NULL; /* we shouldn't need this */ |
4b42e4f6 |
366 | pr->dynamic = 0; |
f26d5c33 |
367 | |
e8fa8f62 |
368 | pr->s = *s = new_connection(addr, dummy_realhost, port, |
369 | 0, 1, 0, (Plug) pr, cfg); |
808c3834 |
370 | if ((err = sk_socket_error(*s)) != NULL) { |
f26d5c33 |
371 | sfree(pr); |
372 | return err; |
373 | } |
374 | |
375 | sk_set_private_ptr(*s, pr); |
376 | sk_addr_free(addr); |
377 | return NULL; |
378 | } |
379 | |
380 | /* |
381 | called when someone connects to the local port |
382 | */ |
383 | |
f7f9fb5c |
384 | static int pfd_accepting(Plug p, OSSocket sock) |
f26d5c33 |
385 | { |
c85623f9 |
386 | static const struct plug_function_table fn_table = { |
f26d5c33 |
387 | pfd_closing, |
388 | pfd_receive, |
5471d09a |
389 | pfd_sent, |
f26d5c33 |
390 | NULL |
391 | }; |
392 | struct PFwdPrivate *pr, *org; |
f26d5c33 |
393 | Socket s; |
cbe2d68f |
394 | const char *err; |
f26d5c33 |
395 | |
f26d5c33 |
396 | org = (struct PFwdPrivate *)p; |
3d88e64d |
397 | pr = snew(struct PFwdPrivate); |
820ebe3b |
398 | pr->buffer = NULL; |
f26d5c33 |
399 | pr->fn = &fn_table; |
400 | |
401 | pr->c = NULL; |
6b78788a |
402 | pr->backhandle = org->backhandle; |
f26d5c33 |
403 | |
404 | pr->s = s = sk_register(sock, (Plug) pr); |
808c3834 |
405 | if ((err = sk_socket_error(s)) != NULL) { |
f26d5c33 |
406 | sfree(pr); |
407 | return err != NULL; |
408 | } |
409 | |
820ebe3b |
410 | sk_set_private_ptr(s, pr); |
f26d5c33 |
411 | |
5471d09a |
412 | pr->throttled = pr->throttle_override = 0; |
f26d5c33 |
413 | pr->ready = 0; |
f26d5c33 |
414 | |
820ebe3b |
415 | if (org->dynamic) { |
416 | pr->dynamic = 1; |
417 | pr->port = 0; /* hostname buffer is so far empty */ |
418 | sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */ |
f26d5c33 |
419 | } else { |
4b42e4f6 |
420 | pr->dynamic = 0; |
820ebe3b |
421 | strcpy(pr->hostname, org->hostname); |
422 | pr->port = org->port; |
423 | pr->c = new_sock_channel(org->backhandle, s); |
424 | |
425 | if (pr->c == NULL) { |
426 | sfree(pr); |
427 | return 1; |
428 | } else { |
429 | /* asks to forward to the specified host/port for this */ |
430 | ssh_send_port_open(pr->c, pr->hostname, pr->port, "forwarding"); |
431 | } |
f26d5c33 |
432 | } |
433 | |
434 | return 0; |
435 | } |
436 | |
437 | |
438 | /* Add a new forwarding from port -> desthost:destport |
6ee9b735 |
439 | sets up a listener on the local machine on (srcaddr:)port |
f26d5c33 |
440 | */ |
cbe2d68f |
441 | const char *pfd_addforward(char *desthost, int destport, char *srcaddr, |
442 | int port, void *backhandle, const Config *cfg) |
f26d5c33 |
443 | { |
c85623f9 |
444 | static const struct plug_function_table fn_table = { |
f26d5c33 |
445 | pfd_closing, |
5471d09a |
446 | pfd_receive, /* should not happen... */ |
447 | pfd_sent, /* also should not happen */ |
f26d5c33 |
448 | pfd_accepting |
449 | }; |
450 | |
cbe2d68f |
451 | const char *err; |
f26d5c33 |
452 | struct PFwdPrivate *pr; |
453 | Socket s; |
454 | |
455 | /* |
456 | * Open socket. |
457 | */ |
3d88e64d |
458 | pr = snew(struct PFwdPrivate); |
820ebe3b |
459 | pr->buffer = NULL; |
f26d5c33 |
460 | pr->fn = &fn_table; |
461 | pr->c = NULL; |
820ebe3b |
462 | if (desthost) { |
463 | strcpy(pr->hostname, desthost); |
464 | pr->port = destport; |
465 | pr->dynamic = 0; |
466 | } else |
467 | pr->dynamic = 1; |
5471d09a |
468 | pr->throttled = pr->throttle_override = 0; |
f26d5c33 |
469 | pr->ready = 0; |
6b78788a |
470 | pr->backhandle = backhandle; |
f26d5c33 |
471 | |
e8fa8f62 |
472 | pr->s = s = new_listener(srcaddr, port, (Plug) pr, |
473 | !cfg->lport_acceptall, cfg); |
808c3834 |
474 | if ((err = sk_socket_error(s)) != NULL) { |
f26d5c33 |
475 | sfree(pr); |
476 | return err; |
477 | } |
478 | |
479 | sk_set_private_ptr(s, pr); |
480 | |
481 | return NULL; |
482 | } |
483 | |
484 | void pfd_close(Socket s) |
485 | { |
486 | struct PFwdPrivate *pr; |
487 | |
488 | if (!s) |
489 | return; |
490 | |
491 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
492 | |
820ebe3b |
493 | sfree(pr->buffer); |
f26d5c33 |
494 | sfree(pr); |
495 | |
496 | sk_close(s); |
497 | } |
498 | |
5471d09a |
499 | void pfd_unthrottle(Socket s) |
500 | { |
501 | struct PFwdPrivate *pr; |
502 | if (!s) |
503 | return; |
504 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
505 | |
506 | pr->throttled = 0; |
507 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
508 | } |
509 | |
510 | void pfd_override_throttle(Socket s, int enable) |
511 | { |
512 | struct PFwdPrivate *pr; |
513 | if (!s) |
514 | return; |
515 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
516 | |
517 | pr->throttle_override = enable; |
518 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
519 | } |
520 | |
f26d5c33 |
521 | /* |
522 | * Called to send data down the raw connection. |
523 | */ |
5471d09a |
524 | int pfd_send(Socket s, char *data, int len) |
f26d5c33 |
525 | { |
f26d5c33 |
526 | if (s == NULL) |
5471d09a |
527 | return 0; |
528 | return sk_write(s, data, len); |
f26d5c33 |
529 | } |
530 | |
531 | |
532 | void pfd_confirm(Socket s) |
533 | { |
5f2e19fc |
534 | struct PFwdPrivate *pr; |
f26d5c33 |
535 | |
536 | if (s == NULL) |
537 | return; |
538 | |
5f2e19fc |
539 | pr = (struct PFwdPrivate *) sk_get_private_ptr(s); |
f26d5c33 |
540 | pr->ready = 1; |
541 | sk_set_frozen(s, 0); |
542 | sk_write(s, NULL, 0); |
820ebe3b |
543 | if (pr->buffer) { |
544 | sshfwd_write(pr->c, pr->buffer, pr->buflen); |
545 | sfree(pr->buffer); |
546 | pr->buffer = NULL; |
547 | } |
f26d5c33 |
548 | } |