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