+/*
+ * Platform-independent bits of X11 forwarding.
+ */
+
#include <stdio.h>
#include <stdlib.h>
+#include <assert.h>
+#include <time.h>
#include "putty.h"
#include "ssh.h"
((unsigned long)(unsigned char)(cp)[3] << 24))
#define PUT_32BIT_LSB_FIRST(cp, value) ( \
- (cp)[0] = (value), \
- (cp)[1] = (value) >> 8, \
- (cp)[2] = (value) >> 16, \
- (cp)[3] = (value) >> 24 )
+ (cp)[0] = (char)(value), \
+ (cp)[1] = (char)((value) >> 8), \
+ (cp)[2] = (char)((value) >> 16), \
+ (cp)[3] = (char)((value) >> 24) )
#define GET_16BIT_LSB_FIRST(cp) \
(((unsigned long)(unsigned char)(cp)[0]) | \
((unsigned long)(unsigned char)(cp)[1] << 8))
#define PUT_16BIT_LSB_FIRST(cp, value) ( \
- (cp)[0] = (value), \
- (cp)[1] = (value) >> 8 )
+ (cp)[0] = (char)(value), \
+ (cp)[1] = (char)((value) >> 8) )
#define GET_32BIT_MSB_FIRST(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 24) | \
((unsigned long)(unsigned char)(cp)[3]))
#define PUT_32BIT_MSB_FIRST(cp, value) ( \
- (cp)[0] = (value) >> 24, \
- (cp)[1] = (value) >> 16, \
- (cp)[2] = (value) >> 8, \
- (cp)[3] = (value) )
+ (cp)[0] = (char)((value) >> 24), \
+ (cp)[1] = (char)((value) >> 16), \
+ (cp)[2] = (char)((value) >> 8), \
+ (cp)[3] = (char)(value) )
#define GET_16BIT_MSB_FIRST(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 8) | \
((unsigned long)(unsigned char)(cp)[1]))
#define PUT_16BIT_MSB_FIRST(cp, value) ( \
- (cp)[0] = (value) >> 8, \
- (cp)[1] = (value) )
+ (cp)[0] = (char)((value) >> 8), \
+ (cp)[1] = (char)(value) )
#define GET_16BIT(endian, cp) \
(endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))
#define PUT_16BIT(endian, cp, val) \
(endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
+const char *const x11_authnames[] = {
+ "", "MIT-MAGIC-COOKIE-1", "XDM-AUTHORIZATION-1"
+};
+
struct X11Auth {
- unsigned char data[64];
- int len;
+ unsigned char fakedata[64], realdata[64];
+ int fakeproto, realproto;
+ int fakelen, reallen;
};
struct X11Private {
int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;
int verified;
int throttled, throttle_override;
+ unsigned long peer_ip;
+ int peer_port;
void *c; /* data used by ssh.c */
Socket s;
};
-void x11_close(Socket s);
-
void *x11_invent_auth(char *proto, int protomaxlen,
- char *data, int datamaxlen)
+ char *data, int datamaxlen, int proto_id)
{
- struct X11Auth *auth = smalloc(sizeof(struct X11Auth));
+ struct X11Auth *auth = snew(struct X11Auth);
char ourdata[64];
int i;
- /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
- auth->len = 16;
- for (i = 0; i < 16; i++)
- auth->data[i] = random_byte();
+ if (proto_id == X11_MIT) {
+ auth->fakeproto = X11_MIT;
+
+ /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
+ auth->fakelen = 16;
+ for (i = 0; i < 16; i++)
+ auth->fakedata[i] = random_byte();
+ } else {
+ assert(proto_id == X11_XDM);
+ auth->fakeproto = X11_XDM;
+
+ /* XDM-AUTHORIZATION-1. Cookie size is 16 bytes; byte 8 is zero. */
+ auth->fakelen = 16;
+ for (i = 0; i < 16; i++)
+ auth->fakedata[i] = (i == 8 ? 0 : random_byte());
+ }
/* Now format for the recipient. */
- strncpy(proto, "MIT-MAGIC-COOKIE-1", protomaxlen);
+ strncpy(proto, x11_authnames[auth->fakeproto], protomaxlen);
ourdata[0] = '\0';
- for (i = 0; i < auth->len; i++)
- sprintf(ourdata + strlen(ourdata), "%02x", auth->data[i]);
+ for (i = 0; i < auth->fakelen; i++)
+ sprintf(ourdata + strlen(ourdata), "%02x", auth->fakedata[i]);
strncpy(data, ourdata, datamaxlen);
return auth;
}
-static int x11_verify(struct X11Auth *auth,
- char *proto, unsigned char *data, int dlen)
+void x11_free_auth(void *auth)
{
- if (strcmp(proto, "MIT-MAGIC-COOKIE-1") != 0)
- return 0; /* wrong protocol attempted */
- if (dlen != auth->len)
- return 0; /* cookie was wrong length */
- if (memcmp(auth->data, data, dlen) != 0)
- return 0; /* cookie was wrong cookie! */
- return 1;
+
+ sfree(auth);
}
-static int x11_closing(Plug plug, char *error_msg, int error_code,
+/*
+ * Fetch the real auth data for a given display string, and store
+ * it in an X11Auth structure. Returns NULL on success, or an error
+ * string.
+ */
+void x11_get_real_auth(void *authv, char *display)
+{
+ struct X11Auth *auth = (struct X11Auth *)authv;
+
+ auth->realproto = X11_NO_AUTH; /* in case next call does nothing */
+
+ auth->reallen = sizeof(auth->realdata);
+ platform_get_x11_auth(display, &auth->realproto,
+ auth->realdata, &auth->reallen);
+}
+
+static char *x11_verify(unsigned long peer_ip, int peer_port,
+ struct X11Auth *auth, char *proto,
+ unsigned char *data, int dlen)
+{
+ if (strcmp(proto, x11_authnames[auth->fakeproto]) != 0)
+ return "wrong authentication protocol attempted";
+ if (auth->fakeproto == X11_MIT) {
+ if (dlen != auth->fakelen)
+ return "MIT-MAGIC-COOKIE-1 data was wrong length";
+ if (memcmp(auth->fakedata, data, dlen) != 0)
+ return "MIT-MAGIC-COOKIE-1 data did not match";
+ }
+ if (auth->fakeproto == X11_XDM) {
+ unsigned long t;
+ time_t tim;
+ int i;
+
+ if (dlen != 24)
+ return "XDM-AUTHORIZATION-1 data was wrong length";
+ if (peer_port == -1)
+ return "cannot do XDM-AUTHORIZATION-1 without remote address data";
+ des_decrypt_xdmauth(auth->fakedata+9, data, 24);
+ if (memcmp(auth->fakedata, data, 8) != 0)
+ return "XDM-AUTHORIZATION-1 data failed check"; /* cookie wrong */
+ if (GET_32BIT_MSB_FIRST(data+8) != peer_ip)
+ return "XDM-AUTHORIZATION-1 data failed check"; /* IP wrong */
+ if ((int)GET_16BIT_MSB_FIRST(data+12) != peer_port)
+ return "XDM-AUTHORIZATION-1 data failed check"; /* port wrong */
+ t = GET_32BIT_MSB_FIRST(data+14);
+ for (i = 18; i < 24; i++)
+ if (data[i] != 0) /* zero padding wrong */
+ return "XDM-AUTHORIZATION-1 data failed check";
+ tim = time(NULL);
+ if (abs(t - tim) > 20*60) /* 20 minute clock skew should be OK */
+ return "XDM-AUTHORIZATION-1 time stamp was too far out";
+ }
+ /* implement other protocols here if ever required */
+ return NULL;
+}
+
+static void x11_log(Plug p, int type, SockAddr addr, int port,
+ const char *error_msg, int error_code)
+{
+ /* We have no interface to the logging module here, so we drop these. */
+}
+
+static int x11_closing(Plug plug, const char *error_msg, int error_code,
int calling_back)
{
struct X11Private *pr = (struct X11Private *) plug;
return atoi(display + n + 1);
}
+/* Find the right display, returns an allocated string */
+char *x11_display(const char *display) {
+ char *ret;
+ if(!display || !*display) {
+ /* try to find platform-specific local display */
+ if(!(ret = platform_get_x_display()))
+ /* plausible default for all platforms */
+ ret = dupstr(":0");
+ } else
+ ret = dupstr(display);
+ if(ret[0] == ':') {
+ /* no transport specified, use whatever we think is best */
+ char *s = dupcat(platform_x11_best_transport, ret, (char *)0);
+ sfree(ret);
+ return s;
+ } else
+ return ret;
+}
+
/*
* Called to set up the raw connection.
*
* Returns an error message, or NULL on success.
* also, fills the SocketsStructure
*/
-char *x11_init(Socket * s, char *display, void *c, void *auth)
+const char *x11_init(Socket * s, char *display, void *c, void *auth,
+ const char *peeraddr, int peerport, const Config *cfg)
{
static const struct plug_function_table fn_table = {
+ x11_log,
x11_closing,
x11_receive,
x11_sent,
SockAddr addr;
int port;
- char *err, *dummy_realhost;
+ const char *err;
+ char *dummy_realhost;
char host[128];
int n, displaynum;
struct X11Private *pr;
+ /* default display */
+ display = x11_display(display);
/*
* Split up display name into host and display-number parts.
*/
n = strcspn(display, ":");
+ assert(n != 0); /* x11_display() promises this */
if (display[n])
displaynum = atoi(display + n + 1);
else
n = sizeof(host) - 1;
strncpy(host, display, n);
host[n] = '\0';
-
- /*
- * Try to find host.
- */
- addr = name_lookup(host, port, &dummy_realhost);
- if ((err = sk_addr_error(addr)))
- return err;
-
- port = 6000 + displaynum;
+ sfree(display);
+
+ if(!strcmp(host, "unix")) {
+ /* use AF_UNIX sockets (doesn't make sense on all platforms) */
+ addr = platform_get_x11_unix_address(displaynum,
+ &dummy_realhost);
+ port = 0; /* to show we are not confused */
+ } else {
+ port = 6000 + displaynum;
+
+ /*
+ * Try to find host.
+ */
+ addr = name_lookup(host, port, &dummy_realhost, cfg, ADDRTYPE_UNSPEC);
+ if ((err = sk_addr_error(addr)) != NULL) {
+ sk_addr_free(addr);
+ return err;
+ }
+ }
/*
* Open socket.
*/
- pr = (struct X11Private *) smalloc(sizeof(struct X11Private));
+ pr = snew(struct X11Private);
pr->fn = &fn_table;
pr->auth_protocol = NULL;
pr->auth = (struct X11Auth *)auth;
pr->throttled = pr->throttle_override = 0;
pr->c = c;
- pr->s = *s = new_connection(addr, dummy_realhost, port, 0, 1, 0, (Plug) pr);
- if ((err = sk_socket_error(*s))) {
+ pr->s = *s = new_connection(addr, dummy_realhost, port,
+ 0, 1, 0, 0, (Plug) pr, cfg);
+ if ((err = sk_socket_error(*s)) != NULL) {
sfree(pr);
return err;
}
+ /*
+ * See if we can make sense of the peer address we were given.
+ */
+ {
+ int i[4];
+ if (peeraddr &&
+ 4 == sscanf(peeraddr, "%d.%d.%d.%d", i+0, i+1, i+2, i+3)) {
+ pr->peer_ip = (i[0] << 24) | (i[1] << 16) | (i[2] << 8) | i[3];
+ pr->peer_port = peerport;
+ } else {
+ pr->peer_ip = 0;
+ pr->peer_port = -1;
+ }
+ }
+
sk_set_private_ptr(*s, pr);
- sk_addr_free(addr);
return NULL;
}
*/
int x11_send(Socket s, char *data, int len)
{
- struct X11Private *pr = (struct X11Private *) sk_get_private_ptr(s);
-
- if (s == NULL)
+ struct X11Private *pr;
+ if (!s)
return 0;
+ pr = (struct X11Private *) sk_get_private_ptr(s);
/*
* Read the first packet.
pr->auth_psize = (pr->auth_plen + 3) & ~3;
pr->auth_dsize = (pr->auth_dlen + 3) & ~3;
/* Leave room for a terminating zero, to make our lives easier. */
- pr->auth_protocol = (char *) smalloc(pr->auth_psize + 1);
- pr->auth_data = (char *) smalloc(pr->auth_dsize);
+ pr->auth_protocol = snewn(pr->auth_psize + 1, char);
+ pr->auth_data = snewn(pr->auth_dsize, unsigned char);
}
/*
* If we haven't verified the authentication, do so now.
*/
if (!pr->verified) {
- int ret;
+ char *err;
pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */
- ret = x11_verify(pr->auth, pr->auth_protocol,
+ err = x11_verify(pr->peer_ip, pr->peer_port,
+ pr->auth, pr->auth_protocol,
pr->auth_data, pr->auth_dlen);
/*
* If authentication failed, construct and send an error
* packet, then terminate the connection.
*/
- if (!ret) {
- char message[] = "Authentication failed at PuTTY X11 proxy";
- unsigned char reply[8 + sizeof(message) + 4];
- int msglen = sizeof(message) - 1; /* skip zero byte */
- int msgsize = (msglen + 3) & ~3;
+ if (err) {
+ char *message;
+ int msglen, msgsize;
+ unsigned char *reply;
+
+ message = dupprintf("PuTTY X11 proxy: %s", err);
+ msglen = strlen(message);
+ reply = snewn(8 + msglen+1 + 4, unsigned char); /* include zero */
+ msgsize = (msglen + 3) & ~3;
reply[0] = 0; /* failure */
reply[1] = msglen; /* length of reason string */
memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */
PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */
memset(reply + 8, 0, msgsize);
memcpy(reply + 8, message, msglen);
- sshfwd_write(pr->c, reply, 8 + msgsize);
+ sshfwd_write(pr->c, (char *)reply, 8 + msgsize);
sshfwd_close(pr->c);
x11_close(s);
+ sfree(reply);
+ sfree(message);
return 0;
}
/*
* Now we know we're going to accept the connection. Strip
- * the auth data. (TODO: if we ever work out how, we should
- * replace some real auth data in here.)
+ * the fake auth data, and optionally put real auth data in
+ * instead.
*/
- PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, 0); /* auth proto */
- PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, 0); /* auth data */
- sk_write(s, pr->firstpkt, 12);
+ {
+ char realauthdata[64];
+ int realauthlen = 0;
+ int authstrlen = strlen(x11_authnames[pr->auth->realproto]);
+ unsigned long ip;
+ int port;
+ static const char zeroes[4] = { 0,0,0,0 };
+
+ if (pr->auth->realproto == X11_MIT) {
+ assert(pr->auth->reallen <= lenof(realauthdata));
+ realauthlen = pr->auth->reallen;
+ memcpy(realauthdata, pr->auth->realdata, realauthlen);
+ } else if (pr->auth->realproto == X11_XDM &&
+ pr->auth->reallen == 16 &&
+ sk_getxdmdata(s, &ip, &port)) {
+ time_t t;
+ realauthlen = 24;
+ memset(realauthdata, 0, 24);
+ memcpy(realauthdata, pr->auth->realdata, 8);
+ PUT_32BIT_MSB_FIRST(realauthdata+8, ip);
+ PUT_16BIT_MSB_FIRST(realauthdata+12, port);
+ t = time(NULL);
+ PUT_32BIT_MSB_FIRST(realauthdata+14, t);
+ des_encrypt_xdmauth(pr->auth->realdata+9,
+ (unsigned char *)realauthdata, 24);
+ }
+ /* implement other auth methods here if required */
+
+ PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, authstrlen);
+ PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, realauthlen);
+
+ sk_write(s, (char *)pr->firstpkt, 12);
+
+ if (authstrlen) {
+ sk_write(s, x11_authnames[pr->auth->realproto], authstrlen);
+ sk_write(s, zeroes, 3 & (-authstrlen));
+ }
+ if (realauthlen) {
+ sk_write(s, realauthdata, realauthlen);
+ sk_write(s, zeroes, 3 & (-realauthlen));
+ }
+ }
pr->verified = 1;
}
projects / u / mdw / putty / blobdiff