sk_nonamelookup() should ensure the sockaddr it returns has `error'
[u/mdw/putty] / x11fwd.c
CommitLineData
9c964e85 1#include <stdio.h>
2#include <stdlib.h>
3
4#include "putty.h"
5#include "ssh.h"
6
9c964e85 7#define GET_32BIT_LSB_FIRST(cp) \
8 (((unsigned long)(unsigned char)(cp)[0]) | \
9 ((unsigned long)(unsigned char)(cp)[1] << 8) | \
10 ((unsigned long)(unsigned char)(cp)[2] << 16) | \
11 ((unsigned long)(unsigned char)(cp)[3] << 24))
12
13#define PUT_32BIT_LSB_FIRST(cp, value) ( \
14 (cp)[0] = (value), \
15 (cp)[1] = (value) >> 8, \
16 (cp)[2] = (value) >> 16, \
17 (cp)[3] = (value) >> 24 )
18
19#define GET_16BIT_LSB_FIRST(cp) \
20 (((unsigned long)(unsigned char)(cp)[0]) | \
21 ((unsigned long)(unsigned char)(cp)[1] << 8))
22
23#define PUT_16BIT_LSB_FIRST(cp, value) ( \
24 (cp)[0] = (value), \
25 (cp)[1] = (value) >> 8 )
26
27#define GET_32BIT_MSB_FIRST(cp) \
28 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
29 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
30 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
31 ((unsigned long)(unsigned char)(cp)[3]))
32
33#define PUT_32BIT_MSB_FIRST(cp, value) ( \
34 (cp)[0] = (value) >> 24, \
35 (cp)[1] = (value) >> 16, \
36 (cp)[2] = (value) >> 8, \
37 (cp)[3] = (value) )
38
39#define GET_16BIT_MSB_FIRST(cp) \
40 (((unsigned long)(unsigned char)(cp)[0] << 8) | \
41 ((unsigned long)(unsigned char)(cp)[1]))
42
43#define PUT_16BIT_MSB_FIRST(cp, value) ( \
44 (cp)[0] = (value) >> 8, \
45 (cp)[1] = (value) )
46
47#define GET_16BIT(endian, cp) \
48 (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))
49
50#define PUT_16BIT(endian, cp, val) \
51 (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
52
302121de 53struct X11Auth {
54 unsigned char data[64];
55 int len;
56};
57
9c964e85 58struct X11Private {
302121de 59 const struct plug_function_table *fn;
7e78000d 60 /* the above variable absolutely *must* be the first in this structure */
32874aea 61 unsigned char firstpkt[12]; /* first X data packet */
302121de 62 struct X11Auth *auth;
9c964e85 63 char *auth_protocol;
64 unsigned char *auth_data;
65 int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;
66 int verified;
5471d09a 67 int throttled, throttle_override;
32874aea 68 void *c; /* data used by ssh.c */
7e78000d 69 Socket s;
9c964e85 70};
71
32874aea 72void x11_close(Socket s);
9c964e85 73
302121de 74void *x11_invent_auth(char *proto, int protomaxlen,
32874aea 75 char *data, int datamaxlen)
76{
302121de 77 struct X11Auth *auth = smalloc(sizeof(struct X11Auth));
9c964e85 78 char ourdata[64];
79 int i;
80
81 /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
302121de 82 auth->len = 16;
9c964e85 83 for (i = 0; i < 16; i++)
302121de 84 auth->data[i] = random_byte();
9c964e85 85
86 /* Now format for the recipient. */
87 strncpy(proto, "MIT-MAGIC-COOKIE-1", protomaxlen);
88 ourdata[0] = '\0';
302121de 89 for (i = 0; i < auth->len; i++)
90 sprintf(ourdata + strlen(ourdata), "%02x", auth->data[i]);
9c964e85 91 strncpy(data, ourdata, datamaxlen);
302121de 92
93 return auth;
9c964e85 94}
95
302121de 96static int x11_verify(struct X11Auth *auth,
97 char *proto, unsigned char *data, int dlen)
32874aea 98{
9c964e85 99 if (strcmp(proto, "MIT-MAGIC-COOKIE-1") != 0)
32874aea 100 return 0; /* wrong protocol attempted */
302121de 101 if (dlen != auth->len)
32874aea 102 return 0; /* cookie was wrong length */
302121de 103 if (memcmp(auth->data, data, dlen) != 0)
32874aea 104 return 0; /* cookie was wrong cookie! */
9c964e85 105 return 1;
106}
107
32874aea 108static int x11_closing(Plug plug, char *error_msg, int error_code,
109 int calling_back)
110{
7e78000d 111 struct X11Private *pr = (struct X11Private *) plug;
112
113 /*
114 * We have no way to communicate down the forwarded connection,
115 * so if an error occurred on the socket, we just ignore it
116 * and treat it like a proper close.
117 */
118 sshfwd_close(pr->c);
119 x11_close(pr->s);
120 return 1;
121}
122
32874aea 123static int x11_receive(Plug plug, int urgent, char *data, int len)
124{
7e78000d 125 struct X11Private *pr = (struct X11Private *) plug;
9c964e85 126
5471d09a 127 if (sshfwd_write(pr->c, data, len) > 0) {
128 pr->throttled = 1;
129 sk_set_frozen(pr->s, 1);
130 }
131
9c964e85 132 return 1;
133}
134
5471d09a 135static void x11_sent(Plug plug, int bufsize)
136{
137 struct X11Private *pr = (struct X11Private *) plug;
138
139 sshfwd_unthrottle(pr->c, bufsize);
140}
141
9c964e85 142/*
143 * Called to set up the raw connection.
144 *
145 * Returns an error message, or NULL on success.
146 * also, fills the SocketsStructure
9c964e85 147 */
302121de 148char *x11_init(Socket * s, char *display, void *c, void *auth)
32874aea 149{
302121de 150 static const struct plug_function_table fn_table = {
7e78000d 151 x11_closing,
5471d09a 152 x11_receive,
153 x11_sent,
154 NULL
7e78000d 155 };
156
9c964e85 157 SockAddr addr;
158 int port;
0c6c9a70 159 char *err, *dummy_realhost;
9c964e85 160 char host[128];
161 int n, displaynum;
162 struct X11Private *pr;
163
164 /*
165 * Split up display name into host and display-number parts.
166 */
167 n = strcspn(display, ":");
168 if (display[n])
32874aea 169 displaynum = atoi(display + n + 1);
9c964e85 170 else
32874aea 171 displaynum = 0; /* sensible default */
172 if (n > sizeof(host) - 1)
173 n = sizeof(host) - 1;
9c964e85 174 strncpy(host, display, n);
175 host[n] = '\0';
176
177 /*
178 * Try to find host.
179 */
b7a189f3 180 addr = name_lookup(host, port, &dummy_realhost);
32874aea 181 if ((err = sk_addr_error(addr)))
9c964e85 182 return err;
183
184 port = 6000 + displaynum;
185
186 /*
187 * Open socket.
188 */
32874aea 189 pr = (struct X11Private *) smalloc(sizeof(struct X11Private));
7e78000d 190 pr->fn = &fn_table;
9c964e85 191 pr->auth_protocol = NULL;
302121de 192 pr->auth = (struct X11Auth *)auth;
9c964e85 193 pr->verified = 0;
194 pr->data_read = 0;
5471d09a 195 pr->throttled = pr->throttle_override = 0;
9c964e85 196 pr->c = c;
197
8eebd221 198 pr->s = *s = new_connection(addr, dummy_realhost, port, 0, 1, 0, (Plug) pr);
32874aea 199 if ((err = sk_socket_error(*s))) {
200 sfree(pr);
7e78000d 201 return err;
202 }
203
9c964e85 204 sk_set_private_ptr(*s, pr);
205 sk_addr_free(addr);
206 return NULL;
207}
208
32874aea 209void x11_close(Socket s)
210{
211 struct X11Private *pr;
d74d141c 212 if (!s)
213 return;
214 pr = (struct X11Private *) sk_get_private_ptr(s);
9c964e85 215 if (pr->auth_protocol) {
32874aea 216 sfree(pr->auth_protocol);
217 sfree(pr->auth_data);
9c964e85 218 }
219
220 sfree(pr);
221
222 sk_close(s);
223}
224
5471d09a 225void x11_unthrottle(Socket s)
226{
227 struct X11Private *pr;
228 if (!s)
229 return;
230 pr = (struct X11Private *) sk_get_private_ptr(s);
231
232 pr->throttled = 0;
233 sk_set_frozen(s, pr->throttled || pr->throttle_override);
234}
235
236void x11_override_throttle(Socket s, int enable)
237{
238 struct X11Private *pr;
239 if (!s)
240 return;
241 pr = (struct X11Private *) sk_get_private_ptr(s);
242
243 pr->throttle_override = enable;
244 sk_set_frozen(s, pr->throttled || pr->throttle_override);
245}
246
9c964e85 247/*
248 * Called to send data down the raw connection.
249 */
5471d09a 250int x11_send(Socket s, char *data, int len)
32874aea 251{
252 struct X11Private *pr = (struct X11Private *) sk_get_private_ptr(s);
9c964e85 253
254 if (s == NULL)
5471d09a 255 return 0;
9c964e85 256
257 /*
258 * Read the first packet.
259 */
260 while (len > 0 && pr->data_read < 12)
32874aea 261 pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++);
9c964e85 262 if (pr->data_read < 12)
5471d09a 263 return 0;
9c964e85 264
265 /*
266 * If we have not allocated the auth_protocol and auth_data
267 * strings, do so now.
268 */
269 if (!pr->auth_protocol) {
32874aea 270 pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6);
271 pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8);
272 pr->auth_psize = (pr->auth_plen + 3) & ~3;
273 pr->auth_dsize = (pr->auth_dlen + 3) & ~3;
274 /* Leave room for a terminating zero, to make our lives easier. */
275 pr->auth_protocol = (char *) smalloc(pr->auth_psize + 1);
276 pr->auth_data = (char *) smalloc(pr->auth_dsize);
9c964e85 277 }
278
279 /*
280 * Read the auth_protocol and auth_data strings.
281 */
282 while (len > 0 && pr->data_read < 12 + pr->auth_psize)
32874aea 283 pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++);
9c964e85 284 while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)
32874aea 285 pr->auth_data[pr->data_read++ - 12 -
286 pr->auth_psize] = (unsigned char) (len--, *data++);
9c964e85 287 if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)
5471d09a 288 return 0;
9c964e85 289
290 /*
291 * If we haven't verified the authentication, do so now.
292 */
293 if (!pr->verified) {
32874aea 294 int ret;
295
296 pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */
302121de 297 ret = x11_verify(pr->auth, pr->auth_protocol,
298 pr->auth_data, pr->auth_dlen);
32874aea 299
300 /*
301 * If authentication failed, construct and send an error
302 * packet, then terminate the connection.
303 */
304 if (!ret) {
305 char message[] = "Authentication failed at PuTTY X11 proxy";
306 unsigned char reply[8 + sizeof(message) + 4];
307 int msglen = sizeof(message) - 1; /* skip zero byte */
308 int msgsize = (msglen + 3) & ~3;
309 reply[0] = 0; /* failure */
310 reply[1] = msglen; /* length of reason string */
311 memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */
75105663 312 PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */
32874aea 313 memset(reply + 8, 0, msgsize);
314 memcpy(reply + 8, message, msglen);
315 sshfwd_write(pr->c, reply, 8 + msgsize);
316 sshfwd_close(pr->c);
317 x11_close(s);
5471d09a 318 return 0;
32874aea 319 }
320
321 /*
322 * Now we know we're going to accept the connection. Strip
323 * the auth data. (TODO: if we ever work out how, we should
324 * replace some real auth data in here.)
325 */
326 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, 0); /* auth proto */
327 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, 0); /* auth data */
328 sk_write(s, pr->firstpkt, 12);
329 pr->verified = 1;
9c964e85 330 }
331
332 /*
333 * After initialisation, just copy data simply.
334 */
335
5471d09a 336 return sk_write(s, data, len);
9c964e85 337}