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) ( \
16 (cp)[0] = (char)(value), \
17 (cp)[1] = (char)((value) >> 8), \
18 (cp)[2] = (char)((value) >> 16), \
19 (cp)[3] = (char)((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) ( \
26 (cp)[0] = (char)(value), \
27 (cp)[1] = (char)((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] = (char)((value) >> 24), \
37 (cp)[1] = (char)((value) >> 16), \
38 (cp)[2] = (char)((value) >> 8), \
39 (cp)[3] = (char)(value) )
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] = (char)((value) >> 8), \
47 (cp)[1] = (char)(value) )
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
;
66 const struct plug_function_table
*fn
;
67 /* the above variable absolutely *must* be the first in this structure */
68 unsigned char firstpkt
[12]; /* first X data packet */
71 unsigned char *auth_data
;
72 int data_read
, auth_plen
, auth_psize
, auth_dlen
, auth_dsize
;
74 int throttled
, throttle_override
;
75 unsigned long peer_ip
;
77 void *c
; /* data used by ssh.c */
81 void *x11_invent_auth(char *proto
, int protomaxlen
,
82 char *data
, int datamaxlen
, int proto_id
)
84 struct X11Auth
*auth
= smalloc(sizeof(struct X11Auth
));
88 if (proto_id
== X11_MIT
) {
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 assert(proto_id
== X11_XDM
);
97 auth
->fakeproto
= X11_XDM
;
99 /* XDM-AUTHORIZATION-1. Cookie size is 16 bytes; byte 8 is zero. */
101 for (i
= 0; i
< 16; i
++)
102 auth
->fakedata
[i
] = (i
== 8 ?
0 : random_byte());
105 /* Now format for the recipient. */
106 strncpy(proto
, x11_authnames
[auth
->fakeproto
], protomaxlen
);
108 for (i
= 0; i
< auth
->fakelen
; i
++)
109 sprintf(ourdata
+ strlen(ourdata
), "%02x", auth
->fakedata
[i
]);
110 strncpy(data
, ourdata
, datamaxlen
);
116 * Fetch the real auth data for a given display string, and store
117 * it in an X11Auth structure. Returns NULL on success, or an error
120 void x11_get_real_auth(void *authv
, char *display
)
122 struct X11Auth
*auth
= (struct X11Auth
*)authv
;
124 auth
->realproto
= X11_NO_AUTH
; /* in case next call does nothing */
126 auth
->reallen
= sizeof(auth
->realdata
);
127 platform_get_x11_auth(display
, &auth
->realproto
,
128 auth
->realdata
, &auth
->reallen
);
131 static char *x11_verify(unsigned long peer_ip
, int peer_port
,
132 struct X11Auth
*auth
, char *proto
,
133 unsigned char *data
, int dlen
)
135 if (strcmp(proto
, x11_authnames
[auth
->fakeproto
]) != 0)
136 return "wrong authentication protocol attempted";
137 if (auth
->fakeproto
== X11_MIT
) {
138 if (dlen
!= auth
->fakelen
)
139 return "MIT-MAGIC-COOKIE-1 data was wrong length";
140 if (memcmp(auth
->fakedata
, data
, dlen
) != 0)
141 return "MIT-MAGIC-COOKIE-1 data did not match";
143 if (auth
->fakeproto
== X11_XDM
) {
149 return "XDM-AUTHORIZATION-1 data was wrong length";
151 return "cannot do XDM-AUTHORIZATION-1 without remote address data";
152 des_decrypt_xdmauth(auth
->fakedata
+9, data
, 24);
153 if (memcmp(auth
->fakedata
, data
, 8) != 0)
154 return "XDM-AUTHORIZATION-1 data failed check"; /* cookie wrong */
155 if (GET_32BIT_MSB_FIRST(data
+8) != peer_ip
)
156 return "XDM-AUTHORIZATION-1 data failed check"; /* IP wrong */
157 if ((int)GET_16BIT_MSB_FIRST(data
+12) != peer_port
)
158 return "XDM-AUTHORIZATION-1 data failed check"; /* port wrong */
159 t
= GET_32BIT_MSB_FIRST(data
+14);
160 for (i
= 18; i
< 24; i
++)
161 if (data
[i
] != 0) /* zero padding wrong */
162 return "XDM-AUTHORIZATION-1 data failed check";
164 if (abs(t
- tim
) > 20*60) /* 20 minute clock skew should be OK */
165 return "XDM-AUTHORIZATION-1 time stamp was too far out";
167 /* implement other protocols here if ever required */
171 static int x11_closing(Plug plug
, char *error_msg
, int error_code
,
174 struct X11Private
*pr
= (struct X11Private
*) plug
;
177 * We have no way to communicate down the forwarded connection,
178 * so if an error occurred on the socket, we just ignore it
179 * and treat it like a proper close.
186 static int x11_receive(Plug plug
, int urgent
, char *data
, int len
)
188 struct X11Private
*pr
= (struct X11Private
*) plug
;
190 if (sshfwd_write(pr
->c
, data
, len
) > 0) {
192 sk_set_frozen(pr
->s
, 1);
198 static void x11_sent(Plug plug
, int bufsize
)
200 struct X11Private
*pr
= (struct X11Private
*) plug
;
202 sshfwd_unthrottle(pr
->c
, bufsize
);
206 * When setting up X forwarding, we should send the screen number
207 * from the specified local display. This function extracts it from
208 * the display string.
210 int x11_get_screen_number(char *display
)
214 n
= strcspn(display
, ":");
217 n
= strcspn(display
, ".");
220 return atoi(display
+ n
+ 1);
224 * Called to set up the raw connection.
226 * Returns an error message, or NULL on success.
227 * also, fills the SocketsStructure
229 char *x11_init(Socket
* s
, char *display
, void *c
, void *auth
,
230 const char *peeraddr
, int peerport
)
232 static const struct plug_function_table fn_table
= {
241 char *err
, *dummy_realhost
;
244 struct X11Private
*pr
;
247 * Split up display name into host and display-number parts.
249 n
= strcspn(display
, ":");
251 displaynum
= atoi(display
+ n
+ 1);
253 displaynum
= 0; /* sensible default */
254 if (n
> sizeof(host
) - 1)
255 n
= sizeof(host
) - 1;
257 strncpy(host
, display
, n
);
261 * Local display numbers, particularly on Unix, often omit
262 * the display part completely.
264 strcpy(host
, "localhost");
267 port
= 6000 + displaynum
;
272 addr
= name_lookup(host
, port
, &dummy_realhost
);
273 if ((err
= sk_addr_error(addr
)) != NULL
)
279 pr
= (struct X11Private
*) smalloc(sizeof(struct X11Private
));
281 pr
->auth_protocol
= NULL
;
282 pr
->auth
= (struct X11Auth
*)auth
;
285 pr
->throttled
= pr
->throttle_override
= 0;
288 pr
->s
= *s
= new_connection(addr
, dummy_realhost
, port
, 0, 1, 0, (Plug
) pr
);
289 if ((err
= sk_socket_error(*s
)) != NULL
) {
295 * See if we can make sense of the peer address we were given.
300 4 == sscanf(peeraddr
, "%d.%d.%d.%d", i
+0, i
+1, i
+2, i
+3)) {
301 pr
->peer_ip
= (i
[0] << 24) | (i
[1] << 16) | (i
[2] << 8) | i
[3];
302 pr
->peer_port
= peerport
;
309 sk_set_private_ptr(*s
, pr
);
314 void x11_close(Socket s
)
316 struct X11Private
*pr
;
319 pr
= (struct X11Private
*) sk_get_private_ptr(s
);
320 if (pr
->auth_protocol
) {
321 sfree(pr
->auth_protocol
);
322 sfree(pr
->auth_data
);
330 void x11_unthrottle(Socket s
)
332 struct X11Private
*pr
;
335 pr
= (struct X11Private
*) sk_get_private_ptr(s
);
338 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
341 void x11_override_throttle(Socket s
, int enable
)
343 struct X11Private
*pr
;
346 pr
= (struct X11Private
*) sk_get_private_ptr(s
);
348 pr
->throttle_override
= enable
;
349 sk_set_frozen(s
, pr
->throttled
|| pr
->throttle_override
);
353 * Called to send data down the raw connection.
355 int x11_send(Socket s
, char *data
, int len
)
357 struct X11Private
*pr
= (struct X11Private
*) sk_get_private_ptr(s
);
363 * Read the first packet.
365 while (len
> 0 && pr
->data_read
< 12)
366 pr
->firstpkt
[pr
->data_read
++] = (unsigned char) (len
--, *data
++);
367 if (pr
->data_read
< 12)
371 * If we have not allocated the auth_protocol and auth_data
372 * strings, do so now.
374 if (!pr
->auth_protocol
) {
375 pr
->auth_plen
= GET_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+ 6);
376 pr
->auth_dlen
= GET_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+ 8);
377 pr
->auth_psize
= (pr
->auth_plen
+ 3) & ~3;
378 pr
->auth_dsize
= (pr
->auth_dlen
+ 3) & ~3;
379 /* Leave room for a terminating zero, to make our lives easier. */
380 pr
->auth_protocol
= (char *) smalloc(pr
->auth_psize
+ 1);
381 pr
->auth_data
= (unsigned char *) smalloc(pr
->auth_dsize
);
385 * Read the auth_protocol and auth_data strings.
387 while (len
> 0 && pr
->data_read
< 12 + pr
->auth_psize
)
388 pr
->auth_protocol
[pr
->data_read
++ - 12] = (len
--, *data
++);
389 while (len
> 0 && pr
->data_read
< 12 + pr
->auth_psize
+ pr
->auth_dsize
)
390 pr
->auth_data
[pr
->data_read
++ - 12 -
391 pr
->auth_psize
] = (unsigned char) (len
--, *data
++);
392 if (pr
->data_read
< 12 + pr
->auth_psize
+ pr
->auth_dsize
)
396 * If we haven't verified the authentication, do so now.
401 pr
->auth_protocol
[pr
->auth_plen
] = '\0'; /* ASCIZ */
402 err
= x11_verify(pr
->peer_ip
, pr
->peer_port
,
403 pr
->auth
, pr
->auth_protocol
,
404 pr
->auth_data
, pr
->auth_dlen
);
407 * If authentication failed, construct and send an error
408 * packet, then terminate the connection.
413 unsigned char *reply
;
415 message
= dupprintf("PuTTY X11 proxy: %s", err
);
416 msglen
= strlen(message
);
417 reply
= smalloc(8 + msglen
+1 + 4); /* include zero byte */
418 msgsize
= (msglen
+ 3) & ~3;
419 reply
[0] = 0; /* failure */
420 reply
[1] = msglen
; /* length of reason string */
421 memcpy(reply
+ 2, pr
->firstpkt
+ 2, 4); /* major/minor proto vsn */
422 PUT_16BIT(pr
->firstpkt
[0], reply
+ 6, msgsize
>> 2);/* data len */
423 memset(reply
+ 8, 0, msgsize
);
424 memcpy(reply
+ 8, message
, msglen
);
425 sshfwd_write(pr
->c
, (char *)reply
, 8 + msgsize
);
434 * Now we know we're going to accept the connection. Strip
435 * the fake auth data, and optionally put real auth data in
439 char realauthdata
[64];
441 int authstrlen
= strlen(x11_authnames
[pr
->auth
->realproto
]);
444 static const char zeroes
[4] = { 0,0,0,0 };
446 if (pr
->auth
->realproto
== X11_MIT
) {
447 assert(pr
->auth
->reallen
<= lenof(realauthdata
));
448 realauthlen
= pr
->auth
->reallen
;
449 memcpy(realauthdata
, pr
->auth
->realdata
, realauthlen
);
450 } else if (pr
->auth
->realproto
== X11_XDM
&&
451 pr
->auth
->reallen
== 16 &&
452 sk_getxdmdata(s
, &ip
, &port
)) {
455 memset(realauthdata
, 0, 24);
456 memcpy(realauthdata
, pr
->auth
->realdata
, 8);
457 PUT_32BIT_MSB_FIRST(realauthdata
+8, ip
);
458 PUT_16BIT_MSB_FIRST(realauthdata
+12, port
);
460 PUT_32BIT_MSB_FIRST(realauthdata
+14, t
);
461 des_encrypt_xdmauth(pr
->auth
->realdata
+9,
462 (unsigned char *)realauthdata
, 24);
464 /* implement other auth methods here if required */
466 PUT_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+ 6, authstrlen
);
467 PUT_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+ 8, realauthlen
);
469 sk_write(s
, (char *)pr
->firstpkt
, 12);
472 sk_write(s
, x11_authnames
[pr
->auth
->realproto
], authstrlen
);
473 sk_write(s
, zeroes
, 3 & (-authstrlen
));
476 sk_write(s
, realauthdata
, realauthlen
);
477 sk_write(s
, zeroes
, 3 & (-realauthlen
));
484 * After initialisation, just copy data simply.
487 return sk_write(s
, data
, len
);