9 #define GET_32BIT_LSB_FIRST(cp) \
10 (((unsigned long)(unsigned char)(cp)[0]) | \
11 ((unsigned long)(unsigned char)(cp)[1] << 8) | \
12 ((unsigned long)(unsigned char)(cp)[2] << 16) | \
13 ((unsigned long)(unsigned char)(cp)[3] << 24))
15 #define PUT_32BIT_LSB_FIRST(cp, value) ( \
17 (cp)[1] = (value) >> 8, \
18 (cp)[2] = (value) >> 16, \
19 (cp)[3] = (value) >> 24 )
21 #define GET_16BIT_LSB_FIRST(cp) \
22 (((unsigned long)(unsigned char)(cp)[0]) | \
23 ((unsigned long)(unsigned char)(cp)[1] << 8))
25 #define PUT_16BIT_LSB_FIRST(cp, value) ( \
27 (cp)[1] = (value) >> 8 )
29 #define GET_32BIT_MSB_FIRST(cp) \
30 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
31 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
32 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
33 ((unsigned long)(unsigned char)(cp)[3]))
35 #define PUT_32BIT_MSB_FIRST(cp, value) ( \
36 (cp)[0] = (value) >> 24, \
37 (cp)[1] = (value) >> 16, \
38 (cp)[2] = (value) >> 8, \
41 #define GET_16BIT_MSB_FIRST(cp) \
42 (((unsigned long)(unsigned char)(cp)[0] << 8) | \
43 ((unsigned long)(unsigned char)(cp)[1]))
45 #define PUT_16BIT_MSB_FIRST(cp, value) ( \
46 (cp)[0] = (value) >> 8, \
49 #define GET_16BIT(endian, cp) \
50 (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))
52 #define PUT_16BIT(endian, cp, val) \
53 (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
55 const char *const x11_authnames[] = {
56 "", "MIT-MAGIC-COOKIE-1", "XDM-AUTHORIZATION-1"
60 unsigned char fakedata[64], realdata[64];
61 int fakeproto, realproto;
65 extern void platform_get_x11_auth(char *display, int *proto,
66 unsigned char *data, int *datalen);
69 const struct plug_function_table *fn;
70 /* the above variable absolutely *must* be the first in this structure */
71 unsigned char firstpkt[12]; /* first X data packet */
74 unsigned char *auth_data;
75 int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;
77 int throttled, throttle_override;
78 void *c; /* data used by ssh.c */
82 void *x11_invent_auth(char *proto, int protomaxlen,
83 char *data, int datamaxlen)
85 struct X11Auth *auth = smalloc(sizeof(struct X11Auth));
89 auth->fakeproto = X11_MIT;
91 /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
93 for (i = 0; i < 16; i++)
94 auth->fakedata[i] = random_byte();
96 /* Now format for the recipient. */
97 strncpy(proto, x11_authnames[auth->fakeproto], protomaxlen);
99 for (i = 0; i < auth->fakelen; i++)
100 sprintf(ourdata + strlen(ourdata), "%02x", auth->fakedata[i]);
101 strncpy(data, ourdata, datamaxlen);
107 * Fetch the real auth data for a given display string, and store
108 * it in an X11Auth structure. Returns NULL on success, or an error
111 void x11_get_real_auth(void *authv, char *display)
113 struct X11Auth *auth = (struct X11Auth *)authv;
115 auth->realproto = X11_NO_AUTH; /* in case next call does nothing */
117 auth->reallen = sizeof(auth->realdata);
118 platform_get_x11_auth(display, &auth->realproto,
119 auth->realdata, &auth->reallen);
122 static int x11_verify(struct X11Auth *auth,
123 char *proto, unsigned char *data, int dlen)
125 if (strcmp(proto, x11_authnames[auth->fakeproto]) != 0)
126 return 0; /* wrong protocol attempted */
127 if (auth->fakeproto == X11_MIT) {
128 if (dlen != auth->fakelen)
129 return 0; /* cookie was wrong length */
130 if (memcmp(auth->fakedata, data, dlen) != 0)
131 return 0; /* cookie was wrong cookie! */
133 /* implement other protocols here if ever required */
137 static int x11_closing(Plug plug, char *error_msg, int error_code,
140 struct X11Private *pr = (struct X11Private *) plug;
143 * We have no way to communicate down the forwarded connection,
144 * so if an error occurred on the socket, we just ignore it
145 * and treat it like a proper close.
152 static int x11_receive(Plug plug, int urgent, char *data, int len)
154 struct X11Private *pr = (struct X11Private *) plug;
156 if (sshfwd_write(pr->c, data, len) > 0) {
158 sk_set_frozen(pr->s, 1);
164 static void x11_sent(Plug plug, int bufsize)
166 struct X11Private *pr = (struct X11Private *) plug;
168 sshfwd_unthrottle(pr->c, bufsize);
172 * When setting up X forwarding, we should send the screen number
173 * from the specified local display. This function extracts it from
174 * the display string.
176 int x11_get_screen_number(char *display)
180 n = strcspn(display, ":");
183 n = strcspn(display, ".");
186 return atoi(display + n + 1);
190 * Called to set up the raw connection.
192 * Returns an error message, or NULL on success.
193 * also, fills the SocketsStructure
195 char *x11_init(Socket * s, char *display, void *c, void *auth)
197 static const struct plug_function_table fn_table = {
206 char *err, *dummy_realhost;
209 struct X11Private *pr;
212 * Split up display name into host and display-number parts.
214 n = strcspn(display, ":");
216 displaynum = atoi(display + n + 1);
218 displaynum = 0; /* sensible default */
219 if (n > sizeof(host) - 1)
220 n = sizeof(host) - 1;
222 strncpy(host, display, n);
226 * Local display numbers, particularly on Unix, often omit
227 * the display part completely.
229 strcpy(host, "localhost");
232 port = 6000 + displaynum;
237 addr = name_lookup(host, port, &dummy_realhost);
238 if ((err = sk_addr_error(addr)) != NULL)
244 pr = (struct X11Private *) smalloc(sizeof(struct X11Private));
246 pr->auth_protocol = NULL;
247 pr->auth = (struct X11Auth *)auth;
250 pr->throttled = pr->throttle_override = 0;
253 pr->s = *s = new_connection(addr, dummy_realhost, port, 0, 1, 0, (Plug) pr);
254 if ((err = sk_socket_error(*s)) != NULL) {
259 sk_set_private_ptr(*s, pr);
264 void x11_close(Socket s)
266 struct X11Private *pr;
269 pr = (struct X11Private *) sk_get_private_ptr(s);
270 if (pr->auth_protocol) {
271 sfree(pr->auth_protocol);
272 sfree(pr->auth_data);
280 void x11_unthrottle(Socket s)
282 struct X11Private *pr;
285 pr = (struct X11Private *) sk_get_private_ptr(s);
288 sk_set_frozen(s, pr->throttled || pr->throttle_override);
291 void x11_override_throttle(Socket s, int enable)
293 struct X11Private *pr;
296 pr = (struct X11Private *) sk_get_private_ptr(s);
298 pr->throttle_override = enable;
299 sk_set_frozen(s, pr->throttled || pr->throttle_override);
303 * Called to send data down the raw connection.
305 int x11_send(Socket s, char *data, int len)
307 struct X11Private *pr = (struct X11Private *) sk_get_private_ptr(s);
313 * Read the first packet.
315 while (len > 0 && pr->data_read < 12)
316 pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++);
317 if (pr->data_read < 12)
321 * If we have not allocated the auth_protocol and auth_data
322 * strings, do so now.
324 if (!pr->auth_protocol) {
325 pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6);
326 pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8);
327 pr->auth_psize = (pr->auth_plen + 3) & ~3;
328 pr->auth_dsize = (pr->auth_dlen + 3) & ~3;
329 /* Leave room for a terminating zero, to make our lives easier. */
330 pr->auth_protocol = (char *) smalloc(pr->auth_psize + 1);
331 pr->auth_data = (unsigned char *) smalloc(pr->auth_dsize);
335 * Read the auth_protocol and auth_data strings.
337 while (len > 0 && pr->data_read < 12 + pr->auth_psize)
338 pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++);
339 while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)
340 pr->auth_data[pr->data_read++ - 12 -
341 pr->auth_psize] = (unsigned char) (len--, *data++);
342 if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)
346 * If we haven't verified the authentication, do so now.
351 pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */
352 ret = x11_verify(pr->auth, pr->auth_protocol,
353 pr->auth_data, pr->auth_dlen);
356 * If authentication failed, construct and send an error
357 * packet, then terminate the connection.
360 char message[] = "Authentication failed at PuTTY X11 proxy";
361 unsigned char reply[8 + sizeof(message) + 4];
362 int msglen = sizeof(message) - 1; /* skip zero byte */
363 int msgsize = (msglen + 3) & ~3;
364 reply[0] = 0; /* failure */
365 reply[1] = msglen; /* length of reason string */
366 memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */
367 PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */
368 memset(reply + 8, 0, msgsize);
369 memcpy(reply + 8, message, msglen);
370 sshfwd_write(pr->c, (char *)reply, 8 + msgsize);
377 * Now we know we're going to accept the connection. Strip
378 * the fake auth data, and optionally put real auth data in
382 char realauthdata[64];
384 int authstrlen = strlen(x11_authnames[pr->auth->realproto]);
387 static const char zeroes[4] = { 0,0,0,0 };
389 if (pr->auth->realproto == X11_MIT) {
390 assert(pr->auth->reallen <= lenof(realauthdata));
391 realauthlen = pr->auth->reallen;
392 memcpy(realauthdata, pr->auth->realdata, realauthlen);
393 } else if (pr->auth->realproto == X11_XDM &&
394 pr->auth->reallen == 16 &&
395 sk_getxdmdata(s, &ip, &port)) {
398 memset(realauthdata, 0, 24);
399 memcpy(realauthdata, pr->auth->realdata, 8);
400 PUT_32BIT_MSB_FIRST(realauthdata+8, ip);
401 PUT_16BIT_MSB_FIRST(realauthdata+12, port);
403 PUT_32BIT_MSB_FIRST(realauthdata+14, t);
404 des_encrypt_xdmauth(pr->auth->realdata+9, realauthdata, 24);
406 /* implement other auth methods here if required */
408 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, authstrlen);
409 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, realauthlen);
411 sk_write(s, (char *)pr->firstpkt, 12);
414 sk_write(s, x11_authnames[pr->auth->realproto], authstrlen);
415 sk_write(s, zeroes, 3 & (-authstrlen));
418 sk_write(s, realauthdata, realauthlen);
419 sk_write(s, zeroes, 3 & (-realauthlen));
426 * After initialisation, just copy data simply.
429 return sk_write(s, data, len);