9c964e85 |
1 | #include <windows.h> |
2 | #include <stdio.h> |
3 | #include <stdlib.h> |
4 | |
5 | #include "putty.h" |
6 | #include "ssh.h" |
7 | |
8 | #ifndef FALSE |
9 | #define FALSE 0 |
10 | #endif |
11 | #ifndef TRUE |
12 | #define TRUE 1 |
13 | #endif |
14 | |
15 | #define GET_32BIT_LSB_FIRST(cp) \ |
16 | (((unsigned long)(unsigned char)(cp)[0]) | \ |
17 | ((unsigned long)(unsigned char)(cp)[1] << 8) | \ |
18 | ((unsigned long)(unsigned char)(cp)[2] << 16) | \ |
19 | ((unsigned long)(unsigned char)(cp)[3] << 24)) |
20 | |
21 | #define PUT_32BIT_LSB_FIRST(cp, value) ( \ |
22 | (cp)[0] = (value), \ |
23 | (cp)[1] = (value) >> 8, \ |
24 | (cp)[2] = (value) >> 16, \ |
25 | (cp)[3] = (value) >> 24 ) |
26 | |
27 | #define GET_16BIT_LSB_FIRST(cp) \ |
28 | (((unsigned long)(unsigned char)(cp)[0]) | \ |
29 | ((unsigned long)(unsigned char)(cp)[1] << 8)) |
30 | |
31 | #define PUT_16BIT_LSB_FIRST(cp, value) ( \ |
32 | (cp)[0] = (value), \ |
33 | (cp)[1] = (value) >> 8 ) |
34 | |
35 | #define GET_32BIT_MSB_FIRST(cp) \ |
36 | (((unsigned long)(unsigned char)(cp)[0] << 24) | \ |
37 | ((unsigned long)(unsigned char)(cp)[1] << 16) | \ |
38 | ((unsigned long)(unsigned char)(cp)[2] << 8) | \ |
39 | ((unsigned long)(unsigned char)(cp)[3])) |
40 | |
41 | #define PUT_32BIT_MSB_FIRST(cp, value) ( \ |
42 | (cp)[0] = (value) >> 24, \ |
43 | (cp)[1] = (value) >> 16, \ |
44 | (cp)[2] = (value) >> 8, \ |
45 | (cp)[3] = (value) ) |
46 | |
47 | #define GET_16BIT_MSB_FIRST(cp) \ |
48 | (((unsigned long)(unsigned char)(cp)[0] << 8) | \ |
49 | ((unsigned long)(unsigned char)(cp)[1])) |
50 | |
51 | #define PUT_16BIT_MSB_FIRST(cp, value) ( \ |
52 | (cp)[0] = (value) >> 8, \ |
53 | (cp)[1] = (value) ) |
54 | |
55 | #define GET_16BIT(endian, cp) \ |
56 | (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp)) |
57 | |
58 | #define PUT_16BIT(endian, cp, val) \ |
59 | (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val)) |
60 | |
9c964e85 |
61 | struct X11Private { |
7e78000d |
62 | struct plug_function_table *fn; |
63 | /* the above variable absolutely *must* be the first in this structure */ |
32874aea |
64 | unsigned char firstpkt[12]; /* first X data packet */ |
9c964e85 |
65 | char *auth_protocol; |
66 | unsigned char *auth_data; |
67 | int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize; |
68 | int verified; |
5471d09a |
69 | int throttled, throttle_override; |
32874aea |
70 | void *c; /* data used by ssh.c */ |
7e78000d |
71 | Socket s; |
9c964e85 |
72 | }; |
73 | |
32874aea |
74 | void x11_close(Socket s); |
9c964e85 |
75 | |
76 | static unsigned char x11_authdata[64]; |
77 | static int x11_authdatalen; |
78 | |
79 | void x11_invent_auth(char *proto, int protomaxlen, |
32874aea |
80 | char *data, int datamaxlen) |
81 | { |
9c964e85 |
82 | char ourdata[64]; |
83 | int i; |
84 | |
85 | /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */ |
86 | x11_authdatalen = 16; |
87 | for (i = 0; i < 16; i++) |
32874aea |
88 | x11_authdata[i] = random_byte(); |
9c964e85 |
89 | |
90 | /* Now format for the recipient. */ |
91 | strncpy(proto, "MIT-MAGIC-COOKIE-1", protomaxlen); |
92 | ourdata[0] = '\0'; |
93 | for (i = 0; i < x11_authdatalen; i++) |
32874aea |
94 | sprintf(ourdata + strlen(ourdata), "%02x", x11_authdata[i]); |
9c964e85 |
95 | strncpy(data, ourdata, datamaxlen); |
96 | } |
97 | |
32874aea |
98 | static int x11_verify(char *proto, unsigned char *data, int dlen) |
99 | { |
9c964e85 |
100 | if (strcmp(proto, "MIT-MAGIC-COOKIE-1") != 0) |
32874aea |
101 | return 0; /* wrong protocol attempted */ |
9c964e85 |
102 | if (dlen != x11_authdatalen) |
32874aea |
103 | return 0; /* cookie was wrong length */ |
9c964e85 |
104 | if (memcmp(x11_authdata, data, dlen) != 0) |
32874aea |
105 | return 0; /* cookie was wrong cookie! */ |
9c964e85 |
106 | return 1; |
107 | } |
108 | |
32874aea |
109 | static int x11_closing(Plug plug, char *error_msg, int error_code, |
110 | int calling_back) |
111 | { |
7e78000d |
112 | struct X11Private *pr = (struct X11Private *) plug; |
113 | |
114 | /* |
115 | * We have no way to communicate down the forwarded connection, |
116 | * so if an error occurred on the socket, we just ignore it |
117 | * and treat it like a proper close. |
118 | */ |
119 | sshfwd_close(pr->c); |
120 | x11_close(pr->s); |
121 | return 1; |
122 | } |
123 | |
32874aea |
124 | static int x11_receive(Plug plug, int urgent, char *data, int len) |
125 | { |
7e78000d |
126 | struct X11Private *pr = (struct X11Private *) plug; |
9c964e85 |
127 | |
5471d09a |
128 | if (sshfwd_write(pr->c, data, len) > 0) { |
129 | pr->throttled = 1; |
130 | sk_set_frozen(pr->s, 1); |
131 | } |
132 | |
9c964e85 |
133 | return 1; |
134 | } |
135 | |
5471d09a |
136 | static void x11_sent(Plug plug, int bufsize) |
137 | { |
138 | struct X11Private *pr = (struct X11Private *) plug; |
139 | |
140 | sshfwd_unthrottle(pr->c, bufsize); |
141 | } |
142 | |
9c964e85 |
143 | /* |
144 | * Called to set up the raw connection. |
145 | * |
146 | * Returns an error message, or NULL on success. |
147 | * also, fills the SocketsStructure |
9c964e85 |
148 | */ |
32874aea |
149 | char *x11_init(Socket * s, char *display, void *c) |
150 | { |
7e78000d |
151 | static struct plug_function_table fn_table = { |
152 | x11_closing, |
5471d09a |
153 | x11_receive, |
154 | x11_sent, |
155 | NULL |
7e78000d |
156 | }; |
157 | |
9c964e85 |
158 | SockAddr addr; |
159 | int port; |
0c6c9a70 |
160 | char *err, *dummy_realhost; |
9c964e85 |
161 | char host[128]; |
162 | int n, displaynum; |
163 | struct X11Private *pr; |
164 | |
165 | /* |
166 | * Split up display name into host and display-number parts. |
167 | */ |
168 | n = strcspn(display, ":"); |
169 | if (display[n]) |
32874aea |
170 | displaynum = atoi(display + n + 1); |
9c964e85 |
171 | else |
32874aea |
172 | displaynum = 0; /* sensible default */ |
173 | if (n > sizeof(host) - 1) |
174 | n = sizeof(host) - 1; |
9c964e85 |
175 | strncpy(host, display, n); |
176 | host[n] = '\0'; |
177 | |
178 | /* |
179 | * Try to find host. |
180 | */ |
0c6c9a70 |
181 | addr = sk_namelookup(host, &dummy_realhost); |
32874aea |
182 | if ((err = sk_addr_error(addr))) |
9c964e85 |
183 | return err; |
184 | |
185 | port = 6000 + displaynum; |
186 | |
187 | /* |
188 | * Open socket. |
189 | */ |
32874aea |
190 | pr = (struct X11Private *) smalloc(sizeof(struct X11Private)); |
7e78000d |
191 | pr->fn = &fn_table; |
9c964e85 |
192 | pr->auth_protocol = NULL; |
193 | pr->verified = 0; |
194 | pr->data_read = 0; |
5471d09a |
195 | pr->throttled = pr->throttle_override = 0; |
9c964e85 |
196 | pr->c = c; |
197 | |
7e78000d |
198 | pr->s = *s = sk_new(addr, port, 0, 1, (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 |
209 | void 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 |
225 | void 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 | |
236 | void 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 |
250 | int 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 */ |
297 | ret = x11_verify(pr->auth_protocol, pr->auth_data, pr->auth_dlen); |
298 | |
299 | /* |
300 | * If authentication failed, construct and send an error |
301 | * packet, then terminate the connection. |
302 | */ |
303 | if (!ret) { |
304 | char message[] = "Authentication failed at PuTTY X11 proxy"; |
305 | unsigned char reply[8 + sizeof(message) + 4]; |
306 | int msglen = sizeof(message) - 1; /* skip zero byte */ |
307 | int msgsize = (msglen + 3) & ~3; |
308 | reply[0] = 0; /* failure */ |
309 | reply[1] = msglen; /* length of reason string */ |
310 | memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */ |
311 | PUT_16BIT(pr->firstpkt[0], reply + 6, msglen >> 2); /* data len */ |
312 | memset(reply + 8, 0, msgsize); |
313 | memcpy(reply + 8, message, msglen); |
314 | sshfwd_write(pr->c, reply, 8 + msgsize); |
315 | sshfwd_close(pr->c); |
316 | x11_close(s); |
5471d09a |
317 | return 0; |
32874aea |
318 | } |
319 | |
320 | /* |
321 | * Now we know we're going to accept the connection. Strip |
322 | * the auth data. (TODO: if we ever work out how, we should |
323 | * replace some real auth data in here.) |
324 | */ |
325 | PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, 0); /* auth proto */ |
326 | PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, 0); /* auth data */ |
327 | sk_write(s, pr->firstpkt, 12); |
328 | pr->verified = 1; |
9c964e85 |
329 | } |
330 | |
331 | /* |
332 | * After initialisation, just copy data simply. |
333 | */ |
334 | |
5471d09a |
335 | return sk_write(s, data, len); |
9c964e85 |
336 | } |