9c964e85 |
1 | #include <windows.h> |
2 | #include <stdio.h> |
3 | #include <stdlib.h> |
4 | |
5 | #include "putty.h" |
6 | #include "ssh.h" |
7 | |
9c964e85 |
8 | #define GET_32BIT_LSB_FIRST(cp) \ |
9 | (((unsigned long)(unsigned char)(cp)[0]) | \ |
10 | ((unsigned long)(unsigned char)(cp)[1] << 8) | \ |
11 | ((unsigned long)(unsigned char)(cp)[2] << 16) | \ |
12 | ((unsigned long)(unsigned char)(cp)[3] << 24)) |
13 | |
14 | #define PUT_32BIT_LSB_FIRST(cp, value) ( \ |
15 | (cp)[0] = (value), \ |
16 | (cp)[1] = (value) >> 8, \ |
17 | (cp)[2] = (value) >> 16, \ |
18 | (cp)[3] = (value) >> 24 ) |
19 | |
20 | #define GET_16BIT_LSB_FIRST(cp) \ |
21 | (((unsigned long)(unsigned char)(cp)[0]) | \ |
22 | ((unsigned long)(unsigned char)(cp)[1] << 8)) |
23 | |
24 | #define PUT_16BIT_LSB_FIRST(cp, value) ( \ |
25 | (cp)[0] = (value), \ |
26 | (cp)[1] = (value) >> 8 ) |
27 | |
28 | #define GET_32BIT_MSB_FIRST(cp) \ |
29 | (((unsigned long)(unsigned char)(cp)[0] << 24) | \ |
30 | ((unsigned long)(unsigned char)(cp)[1] << 16) | \ |
31 | ((unsigned long)(unsigned char)(cp)[2] << 8) | \ |
32 | ((unsigned long)(unsigned char)(cp)[3])) |
33 | |
34 | #define PUT_32BIT_MSB_FIRST(cp, value) ( \ |
35 | (cp)[0] = (value) >> 24, \ |
36 | (cp)[1] = (value) >> 16, \ |
37 | (cp)[2] = (value) >> 8, \ |
38 | (cp)[3] = (value) ) |
39 | |
40 | #define GET_16BIT_MSB_FIRST(cp) \ |
41 | (((unsigned long)(unsigned char)(cp)[0] << 8) | \ |
42 | ((unsigned long)(unsigned char)(cp)[1])) |
43 | |
44 | #define PUT_16BIT_MSB_FIRST(cp, value) ( \ |
45 | (cp)[0] = (value) >> 8, \ |
46 | (cp)[1] = (value) ) |
47 | |
48 | #define GET_16BIT(endian, cp) \ |
49 | (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp)) |
50 | |
51 | #define PUT_16BIT(endian, cp, val) \ |
52 | (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val)) |
53 | |
9c964e85 |
54 | struct X11Private { |
7e78000d |
55 | struct plug_function_table *fn; |
56 | /* the above variable absolutely *must* be the first in this structure */ |
32874aea |
57 | unsigned char firstpkt[12]; /* first X data packet */ |
9c964e85 |
58 | char *auth_protocol; |
59 | unsigned char *auth_data; |
60 | int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize; |
61 | int verified; |
5471d09a |
62 | int throttled, throttle_override; |
32874aea |
63 | void *c; /* data used by ssh.c */ |
7e78000d |
64 | Socket s; |
9c964e85 |
65 | }; |
66 | |
32874aea |
67 | void x11_close(Socket s); |
9c964e85 |
68 | |
69 | static unsigned char x11_authdata[64]; |
70 | static int x11_authdatalen; |
71 | |
72 | void x11_invent_auth(char *proto, int protomaxlen, |
32874aea |
73 | char *data, int datamaxlen) |
74 | { |
9c964e85 |
75 | char ourdata[64]; |
76 | int i; |
77 | |
78 | /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */ |
79 | x11_authdatalen = 16; |
80 | for (i = 0; i < 16; i++) |
32874aea |
81 | x11_authdata[i] = random_byte(); |
9c964e85 |
82 | |
83 | /* Now format for the recipient. */ |
84 | strncpy(proto, "MIT-MAGIC-COOKIE-1", protomaxlen); |
85 | ourdata[0] = '\0'; |
86 | for (i = 0; i < x11_authdatalen; i++) |
32874aea |
87 | sprintf(ourdata + strlen(ourdata), "%02x", x11_authdata[i]); |
9c964e85 |
88 | strncpy(data, ourdata, datamaxlen); |
89 | } |
90 | |
32874aea |
91 | static int x11_verify(char *proto, unsigned char *data, int dlen) |
92 | { |
9c964e85 |
93 | if (strcmp(proto, "MIT-MAGIC-COOKIE-1") != 0) |
32874aea |
94 | return 0; /* wrong protocol attempted */ |
9c964e85 |
95 | if (dlen != x11_authdatalen) |
32874aea |
96 | return 0; /* cookie was wrong length */ |
9c964e85 |
97 | if (memcmp(x11_authdata, data, dlen) != 0) |
32874aea |
98 | return 0; /* cookie was wrong cookie! */ |
9c964e85 |
99 | return 1; |
100 | } |
101 | |
32874aea |
102 | static int x11_closing(Plug plug, char *error_msg, int error_code, |
103 | int calling_back) |
104 | { |
7e78000d |
105 | struct X11Private *pr = (struct X11Private *) plug; |
106 | |
107 | /* |
108 | * We have no way to communicate down the forwarded connection, |
109 | * so if an error occurred on the socket, we just ignore it |
110 | * and treat it like a proper close. |
111 | */ |
112 | sshfwd_close(pr->c); |
113 | x11_close(pr->s); |
114 | return 1; |
115 | } |
116 | |
32874aea |
117 | static int x11_receive(Plug plug, int urgent, char *data, int len) |
118 | { |
7e78000d |
119 | struct X11Private *pr = (struct X11Private *) plug; |
9c964e85 |
120 | |
5471d09a |
121 | if (sshfwd_write(pr->c, data, len) > 0) { |
122 | pr->throttled = 1; |
123 | sk_set_frozen(pr->s, 1); |
124 | } |
125 | |
9c964e85 |
126 | return 1; |
127 | } |
128 | |
5471d09a |
129 | static void x11_sent(Plug plug, int bufsize) |
130 | { |
131 | struct X11Private *pr = (struct X11Private *) plug; |
132 | |
133 | sshfwd_unthrottle(pr->c, bufsize); |
134 | } |
135 | |
9c964e85 |
136 | /* |
137 | * Called to set up the raw connection. |
138 | * |
139 | * Returns an error message, or NULL on success. |
140 | * also, fills the SocketsStructure |
9c964e85 |
141 | */ |
32874aea |
142 | char *x11_init(Socket * s, char *display, void *c) |
143 | { |
7e78000d |
144 | static struct plug_function_table fn_table = { |
145 | x11_closing, |
5471d09a |
146 | x11_receive, |
147 | x11_sent, |
148 | NULL |
7e78000d |
149 | }; |
150 | |
9c964e85 |
151 | SockAddr addr; |
152 | int port; |
0c6c9a70 |
153 | char *err, *dummy_realhost; |
9c964e85 |
154 | char host[128]; |
155 | int n, displaynum; |
156 | struct X11Private *pr; |
157 | |
158 | /* |
159 | * Split up display name into host and display-number parts. |
160 | */ |
161 | n = strcspn(display, ":"); |
162 | if (display[n]) |
32874aea |
163 | displaynum = atoi(display + n + 1); |
9c964e85 |
164 | else |
32874aea |
165 | displaynum = 0; /* sensible default */ |
166 | if (n > sizeof(host) - 1) |
167 | n = sizeof(host) - 1; |
9c964e85 |
168 | strncpy(host, display, n); |
169 | host[n] = '\0'; |
170 | |
171 | /* |
172 | * Try to find host. |
173 | */ |
0c6c9a70 |
174 | addr = sk_namelookup(host, &dummy_realhost); |
32874aea |
175 | if ((err = sk_addr_error(addr))) |
9c964e85 |
176 | return err; |
177 | |
178 | port = 6000 + displaynum; |
179 | |
180 | /* |
181 | * Open socket. |
182 | */ |
32874aea |
183 | pr = (struct X11Private *) smalloc(sizeof(struct X11Private)); |
7e78000d |
184 | pr->fn = &fn_table; |
9c964e85 |
185 | pr->auth_protocol = NULL; |
186 | pr->verified = 0; |
187 | pr->data_read = 0; |
5471d09a |
188 | pr->throttled = pr->throttle_override = 0; |
9c964e85 |
189 | pr->c = c; |
190 | |
2184a5d9 |
191 | pr->s = *s = sk_new(addr, port, 0, 1, 0, (Plug) pr); |
32874aea |
192 | if ((err = sk_socket_error(*s))) { |
193 | sfree(pr); |
7e78000d |
194 | return err; |
195 | } |
196 | |
9c964e85 |
197 | sk_set_private_ptr(*s, pr); |
198 | sk_addr_free(addr); |
199 | return NULL; |
200 | } |
201 | |
32874aea |
202 | void x11_close(Socket s) |
203 | { |
204 | struct X11Private *pr; |
d74d141c |
205 | if (!s) |
206 | return; |
207 | pr = (struct X11Private *) sk_get_private_ptr(s); |
9c964e85 |
208 | if (pr->auth_protocol) { |
32874aea |
209 | sfree(pr->auth_protocol); |
210 | sfree(pr->auth_data); |
9c964e85 |
211 | } |
212 | |
213 | sfree(pr); |
214 | |
215 | sk_close(s); |
216 | } |
217 | |
5471d09a |
218 | void x11_unthrottle(Socket s) |
219 | { |
220 | struct X11Private *pr; |
221 | if (!s) |
222 | return; |
223 | pr = (struct X11Private *) sk_get_private_ptr(s); |
224 | |
225 | pr->throttled = 0; |
226 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
227 | } |
228 | |
229 | void x11_override_throttle(Socket s, int enable) |
230 | { |
231 | struct X11Private *pr; |
232 | if (!s) |
233 | return; |
234 | pr = (struct X11Private *) sk_get_private_ptr(s); |
235 | |
236 | pr->throttle_override = enable; |
237 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
238 | } |
239 | |
9c964e85 |
240 | /* |
241 | * Called to send data down the raw connection. |
242 | */ |
5471d09a |
243 | int x11_send(Socket s, char *data, int len) |
32874aea |
244 | { |
245 | struct X11Private *pr = (struct X11Private *) sk_get_private_ptr(s); |
9c964e85 |
246 | |
247 | if (s == NULL) |
5471d09a |
248 | return 0; |
9c964e85 |
249 | |
250 | /* |
251 | * Read the first packet. |
252 | */ |
253 | while (len > 0 && pr->data_read < 12) |
32874aea |
254 | pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++); |
9c964e85 |
255 | if (pr->data_read < 12) |
5471d09a |
256 | return 0; |
9c964e85 |
257 | |
258 | /* |
259 | * If we have not allocated the auth_protocol and auth_data |
260 | * strings, do so now. |
261 | */ |
262 | if (!pr->auth_protocol) { |
32874aea |
263 | pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6); |
264 | pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8); |
265 | pr->auth_psize = (pr->auth_plen + 3) & ~3; |
266 | pr->auth_dsize = (pr->auth_dlen + 3) & ~3; |
267 | /* Leave room for a terminating zero, to make our lives easier. */ |
268 | pr->auth_protocol = (char *) smalloc(pr->auth_psize + 1); |
269 | pr->auth_data = (char *) smalloc(pr->auth_dsize); |
9c964e85 |
270 | } |
271 | |
272 | /* |
273 | * Read the auth_protocol and auth_data strings. |
274 | */ |
275 | while (len > 0 && pr->data_read < 12 + pr->auth_psize) |
32874aea |
276 | pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++); |
9c964e85 |
277 | while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize) |
32874aea |
278 | pr->auth_data[pr->data_read++ - 12 - |
279 | pr->auth_psize] = (unsigned char) (len--, *data++); |
9c964e85 |
280 | if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize) |
5471d09a |
281 | return 0; |
9c964e85 |
282 | |
283 | /* |
284 | * If we haven't verified the authentication, do so now. |
285 | */ |
286 | if (!pr->verified) { |
32874aea |
287 | int ret; |
288 | |
289 | pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */ |
290 | ret = x11_verify(pr->auth_protocol, pr->auth_data, pr->auth_dlen); |
291 | |
292 | /* |
293 | * If authentication failed, construct and send an error |
294 | * packet, then terminate the connection. |
295 | */ |
296 | if (!ret) { |
297 | char message[] = "Authentication failed at PuTTY X11 proxy"; |
298 | unsigned char reply[8 + sizeof(message) + 4]; |
299 | int msglen = sizeof(message) - 1; /* skip zero byte */ |
300 | int msgsize = (msglen + 3) & ~3; |
301 | reply[0] = 0; /* failure */ |
302 | reply[1] = msglen; /* length of reason string */ |
303 | memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */ |
75105663 |
304 | PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */ |
32874aea |
305 | memset(reply + 8, 0, msgsize); |
306 | memcpy(reply + 8, message, msglen); |
307 | sshfwd_write(pr->c, reply, 8 + msgsize); |
308 | sshfwd_close(pr->c); |
309 | x11_close(s); |
5471d09a |
310 | return 0; |
32874aea |
311 | } |
312 | |
313 | /* |
314 | * Now we know we're going to accept the connection. Strip |
315 | * the auth data. (TODO: if we ever work out how, we should |
316 | * replace some real auth data in here.) |
317 | */ |
318 | PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, 0); /* auth proto */ |
319 | PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, 0); /* auth data */ |
320 | sk_write(s, pr->firstpkt, 12); |
321 | pr->verified = 1; |
9c964e85 |
322 | } |
323 | |
324 | /* |
325 | * After initialisation, just copy data simply. |
326 | */ |
327 | |
5471d09a |
328 | return sk_write(s, data, len); |
9c964e85 |
329 | } |