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 unsigned char firstpkt
[12]; /* first X data packet */
67 unsigned char *auth_data
;
68 int data_read
, auth_plen
, auth_psize
, auth_dlen
, auth_dsize
;
70 void *c
; /* data used by ssh.c */
73 void x11_close (Socket s
);
75 static unsigned char x11_authdata
[64];
76 static int x11_authdatalen
;
78 void x11_invent_auth(char *proto
, int protomaxlen
,
79 char *data
, int datamaxlen
) {
83 /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
85 for (i
= 0; i
< 16; i
++)
86 x11_authdata
[i
] = random_byte();
88 /* Now format for the recipient. */
89 strncpy(proto
, "MIT-MAGIC-COOKIE-1", protomaxlen
);
91 for (i
= 0; i
< x11_authdatalen
; i
++)
92 sprintf(ourdata
+strlen(ourdata
), "%02x", x11_authdata
[i
]);
93 strncpy(data
, ourdata
, datamaxlen
);
96 static int x11_verify(char *proto
, unsigned char *data
, int dlen
) {
97 if (strcmp(proto
, "MIT-MAGIC-COOKIE-1") != 0)
98 return 0; /* wrong protocol attempted */
99 if (dlen
!= x11_authdatalen
)
100 return 0; /* cookie was wrong length */
101 if (memcmp(x11_authdata
, data
, dlen
) != 0)
102 return 0; /* cookie was wrong cookie! */
106 static int x11_receive (Socket s
, int urgent
, char *data
, int len
) {
107 struct X11Private
*pr
= (struct X11Private
*)sk_get_private_ptr(s
);
111 * A socket error has occurred. We have no way to
112 * communicate this down the forwarded connection, so we'll
113 * just treat it like a proper close.
118 /* Connection has closed. */
123 sshfwd_write(pr
->c
, data
, len
);
128 * Called to set up the raw connection.
130 * Returns an error message, or NULL on success.
131 * also, fills the SocketsStructure
133 char *x11_init (Socket
*s
, char *display
, void *c
) {
136 char *err
, *dummy_realhost
;
139 struct X11Private
*pr
;
142 * Split up display name into host and display-number parts.
144 n
= strcspn(display
, ":");
146 displaynum
= atoi(display
+n
+1);
148 displaynum
= 0; /* sensible default */
149 if (n
> sizeof(host
)-1)
151 strncpy(host
, display
, n
);
157 addr
= sk_namelookup(host
, &dummy_realhost
);
158 if ( (err
= sk_addr_error(addr
)) )
161 port
= 6000 + displaynum
;
166 *s
= sk_new(addr
, port
, 0, x11_receive
);
167 if ( (err
= sk_socket_error(*s
)) )
170 pr
= (struct X11Private
*)smalloc(sizeof(struct X11Private
));
171 pr
->auth_protocol
= NULL
;
176 sk_set_private_ptr(*s
, pr
);
181 void x11_close (Socket s
) {
182 struct X11Private
*pr
= (struct X11Private
*)sk_get_private_ptr(s
);
184 if (pr
->auth_protocol
) {
185 sfree(pr
->auth_protocol
);
186 sfree(pr
->auth_data
);
195 * Called to send data down the raw connection.
197 void x11_send (Socket s
, char *data
, int len
) {
198 struct X11Private
*pr
= (struct X11Private
*)sk_get_private_ptr(s
);
204 * Read the first packet.
206 while (len
> 0 && pr
->data_read
< 12)
207 pr
->firstpkt
[pr
->data_read
++] = (unsigned char)(len
--, *data
++);
208 if (pr
->data_read
< 12)
212 * If we have not allocated the auth_protocol and auth_data
213 * strings, do so now.
215 if (!pr
->auth_protocol
) {
216 pr
->auth_plen
= GET_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+6);
217 pr
->auth_dlen
= GET_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+8);
218 pr
->auth_psize
= (pr
->auth_plen
+ 3) &~ 3;
219 pr
->auth_dsize
= (pr
->auth_dlen
+ 3) &~ 3;
220 /* Leave room for a terminating zero, to make our lives easier. */
221 pr
->auth_protocol
= (char *)smalloc(pr
->auth_psize
+1);
222 pr
->auth_data
= (char *)smalloc(pr
->auth_dsize
);
226 * Read the auth_protocol and auth_data strings.
228 while (len
> 0 && pr
->data_read
< 12 + pr
->auth_psize
)
229 pr
->auth_protocol
[pr
->data_read
++ - 12] = (len
--, *data
++);
230 while (len
> 0 && pr
->data_read
< 12 + pr
->auth_psize
+ pr
->auth_dsize
)
231 pr
->auth_data
[pr
->data_read
++ - 12 -
232 pr
->auth_psize
] = (unsigned char)(len
--, *data
++);
233 if (pr
->data_read
< 12 + pr
->auth_psize
+ pr
->auth_dsize
)
237 * If we haven't verified the authentication, do so now.
242 pr
->auth_protocol
[pr
->auth_plen
] = '\0'; /* ASCIZ */
243 ret
= x11_verify(pr
->auth_protocol
, pr
->auth_data
, pr
->auth_dlen
);
246 * If authentication failed, construct and send an error
247 * packet, then terminate the connection.
250 char message
[] = "Authentication failed at PuTTY X11 proxy";
251 unsigned char reply
[8 + sizeof(message
) + 4];
252 int msglen
= sizeof(message
)-1; /* skip zero byte */
253 int msgsize
= (msglen
+3) &~ 3;
254 reply
[0] = 0; /* failure */
255 reply
[1] = msglen
; /* length of reason string */
256 memcpy(reply
+2, pr
->firstpkt
+2, 4); /* major/minor proto vsn */
257 PUT_16BIT(pr
->firstpkt
[0], reply
+6, msglen
>> 2); /* data len */
258 memset(reply
+8, 0, msgsize
);
259 memcpy(reply
+8, message
, msglen
);
260 sshfwd_write(pr
->c
, reply
, 8+msgsize
);
267 * Now we know we're going to accept the connection. Strip
268 * the auth data. (TODO: if we ever work out how, we should
269 * replace some real auth data in here.)
271 PUT_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+6, 0); /* auth proto */
272 PUT_16BIT(pr
->firstpkt
[0], pr
->firstpkt
+8, 0); /* auth data */
273 sk_write(s
, pr
->firstpkt
, 12);
278 * After initialisation, just copy data simply.
281 sk_write(s
, data
, len
);