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))
21 #define PUT_32BIT_LSB_FIRST(cp, value) ( \
23 (cp)[1] = (value) >> 8, \
24 (cp)[2] = (value) >> 16, \
25 (cp)[3] = (value) >> 24 )
27 #define GET_16BIT_LSB_FIRST(cp) \
28 (((unsigned long)(unsigned char)(cp)[0]) | \
29 ((unsigned long)(unsigned char)(cp)[1] << 8))
31 #define PUT_16BIT_LSB_FIRST(cp, value) ( \
33 (cp)[1] = (value) >> 8 )
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]))
41 #define PUT_32BIT_MSB_FIRST(cp, value) ( \
42 (cp)[0] = (value) >> 24, \
43 (cp)[1] = (value) >> 16, \
44 (cp)[2] = (value) >> 8, \
47 #define GET_16BIT_MSB_FIRST(cp) \
48 (((unsigned long)(unsigned char)(cp)[0] << 8) | \
49 ((unsigned long)(unsigned char)(cp)[1]))
51 #define PUT_16BIT_MSB_FIRST(cp, value) ( \
52 (cp)[0] = (value) >> 8, \
55 #define GET_16BIT(endian, cp) \
56 (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))
58 #define PUT_16BIT(endian, cp, val) \
59 (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
61 extern void sshfwd_close(void *);
62 extern void sshfwd_write(void *, char *, int);
65 struct plug_function_table
*fn
;
66 /* the above variable absolutely *must* be the first in this structure */
67 unsigned char firstpkt
[12]; /* first X data packet */
69 unsigned char *auth_data
;
70 int data_read
, auth_plen
, auth_psize
, auth_dlen
, auth_dsize
;
72 void *c
; /* data used by ssh.c */
76 void x11_close (Socket s
);
78 static unsigned char x11_authdata
[64];
79 static int x11_authdatalen
;
81 void x11_invent_auth(char *proto
, int protomaxlen
,
82 char *data
, int datamaxlen
) {
86 /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
88 for (i
= 0; i
< 16; i
++)
89 x11_authdata
[i
] = random_byte();
91 /* Now format for the recipient. */
92 strncpy(proto
, "MIT-MAGIC-COOKIE-1", protomaxlen
);
94 for (i
= 0; i
< x11_authdatalen
; i
++)
95 sprintf(ourdata
+strlen(ourdata
), "%02x", x11_authdata
[i
]);
96 strncpy(data
, ourdata
, datamaxlen
);
99 static int x11_verify(char *proto
, unsigned char *data
, int dlen
) {
100 if (strcmp(proto
, "MIT-MAGIC-COOKIE-1") != 0)
101 return 0; /* wrong protocol attempted */
102 if (dlen
!= x11_authdatalen
)
103 return 0; /* cookie was wrong length */
104 if (memcmp(x11_authdata
, data
, dlen
) != 0)
105 return 0; /* cookie was wrong cookie! */
109 static int x11_closing (Plug plug
, char *error_msg
, int error_code
, int calling_back
) {
110 struct X11Private
*pr
= (struct X11Private
*) plug
;
113 * We have no way to communicate down the forwarded connection,
114 * so if an error occurred on the socket, we just ignore it
115 * and treat it like a proper close.
122 static int x11_receive (Plug plug
, int urgent
, char *data
, int len
) {
123 struct X11Private
*pr
= (struct X11Private
*) plug
;
125 sshfwd_write(pr
->c
, data
, len
);
130 * Called to set up the raw connection.
132 * Returns an error message, or NULL on success.
133 * also, fills the SocketsStructure
135 char *x11_init (Socket
*s
, char *display
, void *c
) {
136 static struct plug_function_table fn_table
= {
143 char *err
, *dummy_realhost
;
146 struct X11Private
*pr
;
149 * Split up display name into host and display-number parts.
151 n
= strcspn(display
, ":");
153 displaynum
= atoi(display
+n
+1);
155 displaynum
= 0; /* sensible default */
156 if (n
> sizeof(host
)-1)
158 strncpy(host
, display
, n
);
164 addr
= sk_namelookup(host
, &dummy_realhost
);
165 if ( (err
= sk_addr_error(addr
)) )
168 port
= 6000 + displaynum
;
173 pr
= (struct X11Private
*)smalloc(sizeof(struct X11Private
));
175 pr
->auth_protocol
= NULL
;
180 pr
->s
= *s
= sk_new(addr
, port
, 0, 1, (Plug
) pr
);
181 if ( (err
= sk_socket_error(*s
)) ) {
186 sk_set_private_ptr(*s
, pr
);
191 void x11_close (Socket s
) {
192 struct X11Private
*pr
;
195 pr
= (struct X11Private
*)sk_get_private_ptr(s
);
197 if (pr
->auth_protocol
) {
198 sfree(pr
->auth_protocol
);
199 sfree(pr
->auth_data
);
208 * Called to send data down the raw connection.
210 void x11_send (Socket s
, char *data
, int len
) {
211 struct X11Private
*pr
= (struct X11Private
*)sk_get_private_ptr(s
);
217 * Read the first packet.
219 while (len
> 0 && pr
->data_read
< 12)
220 pr
->firstpkt
[pr
->data_read
++] = (unsigned char)(len
--, *data
++);
221 if (pr
->data_read
< 12)
225 * If we have not allocated the auth_protocol and auth_data
226 * strings, do so now.
228 if (!pr
->auth_protocol
) {
229 pr
->auth_plen
= GET_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+6);
230 pr
->auth_dlen
= GET_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+8);
231 pr
->auth_psize
= (pr
->auth_plen
+ 3) &~ 3;
232 pr
->auth_dsize
= (pr
->auth_dlen
+ 3) &~ 3;
233 /* Leave room for a terminating zero, to make our lives easier. */
234 pr
->auth_protocol
= (char *)smalloc(pr
->auth_psize
+1);
235 pr
->auth_data
= (char *)smalloc(pr
->auth_dsize
);
239 * Read the auth_protocol and auth_data strings.
241 while (len
> 0 && pr
->data_read
< 12 + pr
->auth_psize
)
242 pr
->auth_protocol
[pr
->data_read
++ - 12] = (len
--, *data
++);
243 while (len
> 0 && pr
->data_read
< 12 + pr
->auth_psize
+ pr
->auth_dsize
)
244 pr
->auth_data
[pr
->data_read
++ - 12 -
245 pr
->auth_psize
] = (unsigned char)(len
--, *data
++);
246 if (pr
->data_read
< 12 + pr
->auth_psize
+ pr
->auth_dsize
)
250 * If we haven't verified the authentication, do so now.
255 pr
->auth_protocol
[pr
->auth_plen
] = '\0'; /* ASCIZ */
256 ret
= x11_verify(pr
->auth_protocol
, pr
->auth_data
, pr
->auth_dlen
);
259 * If authentication failed, construct and send an error
260 * packet, then terminate the connection.
263 char message
[] = "Authentication failed at PuTTY X11 proxy";
264 unsigned char reply
[8 + sizeof(message
) + 4];
265 int msglen
= sizeof(message
)-1; /* skip zero byte */
266 int msgsize
= (msglen
+3) &~ 3;
267 reply
[0] = 0; /* failure */
268 reply
[1] = msglen
; /* length of reason string */
269 memcpy(reply
+2, pr
->firstpkt
+2, 4); /* major/minor proto vsn */
270 PUT_16BIT(pr
->firstpkt
[0], reply
+6, msglen
>> 2); /* data len */
271 memset(reply
+8, 0, msgsize
);
272 memcpy(reply
+8, message
, msglen
);
273 sshfwd_write(pr
->c
, reply
, 8+msgsize
);
280 * Now we know we're going to accept the connection. Strip
281 * the auth data. (TODO: if we ever work out how, we should
282 * replace some real auth data in here.)
284 PUT_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+6, 0); /* auth proto */
285 PUT_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+8, 0); /* auth data */
286 sk_write(s
, pr
->firstpkt
, 12);
291 * After initialisation, just copy data simply.
294 sk_write(s
, data
, len
);