Remove tools again. Should have done it with svn merge --reintegrate

1 files changed, 0 insertions, 791 deletions

diff --git a/tools/plink/x11fwd.c b/tools/plink/x11fwd.c
deleted file mode 100644
index 9f22a2364..000000000
--- a/tools/plink/x11fwd.c
+++ /dev/null
@@ -1,791 +0,0 @@
-/*

- * Platform-independent bits of X11 forwarding.

- */

-

-#include <stdio.h>

-#include <stdlib.h>

-#include <assert.h>

-#include <time.h>

-

-#include "putty.h"

-#include "ssh.h"

-#include "tree234.h"

-

-#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 XDMSeen {

-    unsigned int time;

-    unsigned char clientid[6];

-};

-

-struct X11Private {

-    const struct plug_function_table *fn;

-    /* the above variable absolutely *must* be the first in this structure */

-    unsigned char firstpkt[12];	       /* first X data packet */

-    struct X11Display *disp;

-    char *auth_protocol;

-    unsigned char *auth_data;

-    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;

-};

-

-static int xdmseen_cmp(void *a, void *b)

-{

-    struct XDMSeen *sa = a, *sb = b;

-    return sa->time > sb->time ? 1 :

-	   sa->time < sb->time ? -1 :

-           memcmp(sa->clientid, sb->clientid, sizeof(sa->clientid));

-}

-

-/* Do-nothing "plug" implementation, used by x11_setup_display() when it

- * creates a trial connection (and then immediately closes it).

- * XXX: bit out of place here, could in principle live in a platform-

- *      independent network.c or something */

-static void dummy_plug_log(Plug p, int type, SockAddr addr, int port,

-			   const char *error_msg, int error_code) { }

-static int dummy_plug_closing

-     (Plug p, const char *error_msg, int error_code, int calling_back)

-{ return 1; }

-static int dummy_plug_receive(Plug p, int urgent, char *data, int len)

-{ return 1; }

-static void dummy_plug_sent(Plug p, int bufsize) { }

-static int dummy_plug_accepting(Plug p, OSSocket sock) { return 1; }

-static const struct plug_function_table dummy_plug = {

-    dummy_plug_log, dummy_plug_closing, dummy_plug_receive,

-    dummy_plug_sent, dummy_plug_accepting

-};

-

-struct X11Display *x11_setup_display(char *display, int authtype,

-				     const Config *cfg)

-{

-    struct X11Display *disp = snew(struct X11Display);

-    char *localcopy;

-    int i;

-

-    if (!display || !*display) {

-	localcopy = platform_get_x_display();

-	if (!localcopy || !*localcopy) {

-	    sfree(localcopy);

-	    localcopy = dupstr(":0");  /* plausible default for any platform */

-	}

-    } else

-	localcopy = dupstr(display);

-

-    /*

-     * Parse the display name.

-     *

-     * We expect this to have one of the following forms:

-     * 

-     *  - the standard X format which looks like

-     *    [ [ protocol '/' ] host ] ':' displaynumber [ '.' screennumber ]

-     *    (X11 also permits a double colon to indicate DECnet, but

-     *    that's not our problem, thankfully!)

-     *

-     * 	- only seen in the wild on MacOS (so far): a pathname to a

-     * 	  Unix-domain socket, which will typically and confusingly

-     * 	  end in ":0", and which I'm currently distinguishing from

-     * 	  the standard scheme by noting that it starts with '/'.

-     */

-    if (localcopy[0] == '/') {

-	disp->unixsocketpath = localcopy;

-	disp->unixdomain = TRUE;

-	disp->hostname = NULL;

-	disp->displaynum = -1;

-	disp->screennum = 0;

-	disp->addr = NULL;

-    } else {

-	char *colon, *dot, *slash;

-	char *protocol, *hostname;

-

-	colon = strrchr(localcopy, ':');

-	if (!colon) {

-	    sfree(disp);

-	    sfree(localcopy);

-	    return NULL;	       /* FIXME: report a specific error? */

-	}

-

-	*colon++ = '\0';

-	dot = strchr(colon, '.');

-	if (dot)

-	    *dot++ = '\0';

-

-	disp->displaynum = atoi(colon);

-	if (dot)

-	    disp->screennum = atoi(dot);

-	else

-	    disp->screennum = 0;

-

-	protocol = NULL;

-	hostname = localcopy;

-	if (colon > localcopy) {

-	    slash = strchr(localcopy, '/');

-	    if (slash) {

-		*slash++ = '\0';

-		protocol = localcopy;

-		hostname = slash;

-	    }

-	}

-

-	disp->hostname = *hostname ? dupstr(hostname) : NULL;

-

-	if (protocol)

-	    disp->unixdomain = (!strcmp(protocol, "local") ||

-				!strcmp(protocol, "unix"));

-	else if (!*hostname || !strcmp(hostname, "unix"))

-	    disp->unixdomain = platform_uses_x11_unix_by_default;

-	else

-	    disp->unixdomain = FALSE;

-

-	if (!disp->hostname && !disp->unixdomain)

-	    disp->hostname = dupstr("localhost");

-

-	disp->unixsocketpath = NULL;

-	disp->addr = NULL;

-

-	sfree(localcopy);

-    }

-

-    /*

-     * Look up the display hostname, if we need to.

-     */

-    if (!disp->unixdomain) {

-	const char *err;

-

-	disp->port = 6000 + disp->displaynum;

-	disp->addr = name_lookup(disp->hostname, disp->port,

-				 &disp->realhost, cfg, ADDRTYPE_UNSPEC);

-    

-	if ((err = sk_addr_error(disp->addr)) != NULL) {

-	    sk_addr_free(disp->addr);

-	    sfree(disp->hostname);

-	    sfree(disp->unixsocketpath);

-	    return NULL;	       /* FIXME: report an error */

-	}

-    }

-

-    /*

-     * Try upgrading an IP-style localhost display to a Unix-socket

-     * display (as the standard X connection libraries do).

-     */

-    if (!disp->unixdomain && sk_address_is_local(disp->addr)) {

-	SockAddr ux = platform_get_x11_unix_address(NULL, disp->displaynum);

-	const char *err = sk_addr_error(ux);

-	if (!err) {

-	    /* Create trial connection to see if there is a useful Unix-domain

-	     * socket */

-	    const struct plug_function_table *dummy = &dummy_plug;

-	    Socket s = sk_new(sk_addr_dup(ux), 0, 0, 0, 0, 0, (Plug)&dummy);

-	    err = sk_socket_error(s);

-	    sk_close(s);

-	}

-	if (err) {

-	    sk_addr_free(ux);

-	} else {

-	    sk_addr_free(disp->addr);

-	    disp->unixdomain = TRUE;

-	    disp->addr = ux;

-	    /* Fill in the rest in a moment */

-	}

-    }

-

-    if (disp->unixdomain) {

-	if (!disp->addr)

-	    disp->addr = platform_get_x11_unix_address(disp->unixsocketpath,

-						       disp->displaynum);

-	if (disp->unixsocketpath)

-	    disp->realhost = dupstr(disp->unixsocketpath);

-	else

-	    disp->realhost = dupprintf("unix:%d", disp->displaynum);

-	disp->port = 0;

-    }

-

-    /*

-     * Invent the remote authorisation details.

-     */

-    if (authtype == X11_MIT) {

-	disp->remoteauthproto = X11_MIT;

-

-	/* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */

-	disp->remoteauthdata = snewn(16, unsigned char);

-	for (i = 0; i < 16; i++)

-	    disp->remoteauthdata[i] = random_byte();

-	disp->remoteauthdatalen = 16;

-

-	disp->xdmseen = NULL;

-    } else {

-	assert(authtype == X11_XDM);

-	disp->remoteauthproto = X11_XDM;

-

-	/* XDM-AUTHORIZATION-1. Cookie size is 16 bytes; byte 8 is zero. */

-	disp->remoteauthdata = snewn(16, unsigned char);

-	for (i = 0; i < 16; i++)

-	    disp->remoteauthdata[i] = (i == 8 ? 0 : random_byte());

-	disp->remoteauthdatalen = 16;

-

-	disp->xdmseen = newtree234(xdmseen_cmp);

-    }

-    disp->remoteauthprotoname = dupstr(x11_authnames[disp->remoteauthproto]);

-    disp->remoteauthdatastring = snewn(disp->remoteauthdatalen * 2 + 1, char);

-    for (i = 0; i < disp->remoteauthdatalen; i++)

-	sprintf(disp->remoteauthdatastring + i*2, "%02x",

-		disp->remoteauthdata[i]);

-

-    /*

-     * Fetch the local authorisation details.

-     */

-    disp->localauthproto = X11_NO_AUTH;

-    disp->localauthdata = NULL;

-    disp->localauthdatalen = 0;

-    platform_get_x11_auth(disp, cfg);

-

-    return disp;

-}

-

-void x11_free_display(struct X11Display *disp)

-{

-    if (disp->xdmseen != NULL) {

-	struct XDMSeen *seen;

-	while ((seen = delpos234(disp->xdmseen, 0)) != NULL)

-	    sfree(seen);

-	freetree234(disp->xdmseen);

-    }

-    sfree(disp->hostname);

-    sfree(disp->unixsocketpath);

-    if (disp->localauthdata)

-	memset(disp->localauthdata, 0, disp->localauthdatalen);

-    sfree(disp->localauthdata);

-    if (disp->remoteauthdata)

-	memset(disp->remoteauthdata, 0, disp->remoteauthdatalen);

-    sfree(disp->remoteauthdata);

-    sfree(disp->remoteauthprotoname);

-    sfree(disp->remoteauthdatastring);

-    sk_addr_free(disp->addr);

-    sfree(disp);

-}

-

-#define XDM_MAXSKEW 20*60      /* 20 minute clock skew should be OK */

-

-static char *x11_verify(unsigned long peer_ip, int peer_port,

-			struct X11Display *disp, char *proto,

-			unsigned char *data, int dlen)

-{

-    if (strcmp(proto, x11_authnames[disp->remoteauthproto]) != 0)

-	return "wrong authorisation protocol attempted";

-    if (disp->remoteauthproto == X11_MIT) {

-        if (dlen != disp->remoteauthdatalen)

-            return "MIT-MAGIC-COOKIE-1 data was wrong length";

-        if (memcmp(disp->remoteauthdata, data, dlen) != 0)

-            return "MIT-MAGIC-COOKIE-1 data did not match";

-    }

-    if (disp->remoteauthproto == X11_XDM) {

-	unsigned long t;

-	time_t tim;

-	int i;

-	struct XDMSeen *seen, *ret;

-

-        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(disp->remoteauthdata+9, data, 24);

-        if (memcmp(disp->remoteauthdata, 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) > XDM_MAXSKEW)

-	    return "XDM-AUTHORIZATION-1 time stamp was too far out";

-	seen = snew(struct XDMSeen);

-	seen->time = t;

-	memcpy(seen->clientid, data+8, 6);

-	assert(disp->xdmseen != NULL);

-	ret = add234(disp->xdmseen, seen);

-	if (ret != seen) {

-	    sfree(seen);

-	    return "XDM-AUTHORIZATION-1 data replayed";

-	}

-	/* While we're here, purge entries too old to be replayed. */

-	for (;;) {

-	    seen = index234(disp->xdmseen, 0);

-	    assert(seen != NULL);

-	    if (t - seen->time <= XDM_MAXSKEW)

-		break;

-	    sfree(delpos234(disp->xdmseen, 0));

-	}

-    }

-    /* implement other protocols here if ever required */

-    return NULL;

-}

-

-void x11_get_auth_from_authfile(struct X11Display *disp,

-				const char *authfilename)

-{

-    FILE *authfp;

-    char *buf, *ptr, *str[4];

-    int len[4];

-    int family, protocol;

-    int ideal_match = FALSE;

-    char *ourhostname = get_hostname();

-

-    /*

-     * Normally we should look for precisely the details specified in

-     * `disp'. However, there's an oddity when the display is local:

-     * displays like "localhost:0" usually have their details stored

-     * in a Unix-domain-socket record (even if there isn't actually a

-     * real Unix-domain socket available, as with OpenSSH's proxy X11

-     * server).

-     *

-     * This is apparently a fudge to get round the meaninglessness of

-     * "localhost" in a shared-home-directory context -- xauth entries

-     * for Unix-domain sockets already disambiguate this by storing

-     * the *local* hostname in the conveniently-blank hostname field,

-     * but IP "localhost" records couldn't do this. So, typically, an

-     * IP "localhost" entry in the auth database isn't present and if

-     * it were it would be ignored.

-     *

-     * However, we don't entirely trust that (say) Windows X servers

-     * won't rely on a straight "localhost" entry, bad idea though

-     * that is; so if we can't find a Unix-domain-socket entry we'll

-     * fall back to an IP-based entry if we can find one.

-     */

-    int localhost = !disp->unixdomain && sk_address_is_local(disp->addr);

-

-    authfp = fopen(authfilename, "rb");

-    if (!authfp)

-	return;

-

-    /* Records in .Xauthority contain four strings of up to 64K each */

-    buf = snewn(65537 * 4, char);

-

-    while (!ideal_match) {

-	int c, i, j, match = FALSE;

-	

-#define GET do { c = fgetc(authfp); if (c == EOF) goto done; c = (unsigned char)c; } while (0)

-	/* Expect a big-endian 2-byte number giving address family */

-	GET; family = c;

-	GET; family = (family << 8) | c;

-	/* Then expect four strings, each composed of a big-endian 2-byte

-	 * length field followed by that many bytes of data */

-	ptr = buf;

-	for (i = 0; i < 4; i++) {

-	    GET; len[i] = c;

-	    GET; len[i] = (len[i] << 8) | c;

-	    str[i] = ptr;

-	    for (j = 0; j < len[i]; j++) {

-		GET; *ptr++ = c;

-	    }

-	    *ptr++ = '\0';

-	}

-#undef GET

-

-	/*

-	 * Now we have a full X authority record in memory. See

-	 * whether it matches the display we're trying to

-	 * authenticate to.

-	 *

-	 * The details we've just read should be interpreted as

-	 * follows:

-	 * 

-	 *  - 'family' is the network address family used to

-	 *    connect to the display. 0 means IPv4; 6 means IPv6;

-	 *    256 means Unix-domain sockets.

-	 * 

-	 *  - str[0] is the network address itself. For IPv4 and

-	 *    IPv6, this is a string of binary data of the

-	 *    appropriate length (respectively 4 and 16 bytes)

-	 *    representing the address in big-endian format, e.g.

-	 *    7F 00 00 01 means IPv4 localhost. For Unix-domain

-	 *    sockets, this is the host name of the machine on

-	 *    which the Unix-domain display resides (so that an

-	 *    .Xauthority file on a shared file system can contain

-	 *    authority entries for Unix-domain displays on

-	 *    several machines without them clashing).

-	 * 

-	 *  - str[1] is the display number. I've no idea why

-	 *    .Xauthority stores this as a string when it has a

-	 *    perfectly good integer format, but there we go.

-	 * 

-	 *  - str[2] is the authorisation method, encoded as its

-	 *    canonical string name (i.e. "MIT-MAGIC-COOKIE-1",

-	 *    "XDM-AUTHORIZATION-1" or something we don't

-	 *    recognise).

-	 * 

-	 *  - str[3] is the actual authorisation data, stored in

-	 *    binary form.

-	 */

-

-	if (disp->displaynum < 0 || disp->displaynum != atoi(str[1]))

-	    continue;		       /* not the one */

-

-	for (protocol = 1; protocol < lenof(x11_authnames); protocol++)

-	    if (!strcmp(str[2], x11_authnames[protocol]))

-		break;

-	if (protocol == lenof(x11_authnames))

-	    continue;  /* don't recognise this protocol, look for another */

-

-	switch (family) {

-	  case 0:   /* IPv4 */

-	    if (!disp->unixdomain &&

-		sk_addrtype(disp->addr) == ADDRTYPE_IPV4) {

-		char buf[4];

-		sk_addrcopy(disp->addr, buf);

-		if (len[0] == 4 && !memcmp(str[0], buf, 4)) {

-		    match = TRUE;

-		    /* If this is a "localhost" entry, note it down

-		     * but carry on looking for a Unix-domain entry. */

-		    ideal_match = !localhost;

-		}

-	    }

-	    break;

-	  case 6:   /* IPv6 */

-	    if (!disp->unixdomain &&

-		sk_addrtype(disp->addr) == ADDRTYPE_IPV6) {

-		char buf[16];

-		sk_addrcopy(disp->addr, buf);

-		if (len[0] == 16 && !memcmp(str[0], buf, 16)) {

-		    match = TRUE;

-		    ideal_match = !localhost;

-		}

-	    }

-	    break;

-	  case 256: /* Unix-domain / localhost */

-	    if ((disp->unixdomain || localhost)

-	       	&& ourhostname && !strcmp(ourhostname, str[0]))

-		/* A matching Unix-domain socket is always the best

-		 * match. */

-		match = ideal_match = TRUE;

-	    break;

-	}

-

-	if (match) {

-	    /* Current best guess -- may be overridden if !ideal_match */

-	    disp->localauthproto = protocol;

-	    sfree(disp->localauthdata); /* free previous guess, if any */

-	    disp->localauthdata = snewn(len[3], unsigned char);

-	    memcpy(disp->localauthdata, str[3], len[3]);

-	    disp->localauthdatalen = len[3];

-	}

-    }

-

-    done:

-    fclose(authfp);

-    memset(buf, 0, 65537 * 4);

-    sfree(buf);

-    sfree(ourhostname);

-}

-

-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;

-

-    /*

-     * We have no way to communicate down the forwarded connection,

-     * so if an error occurred on the socket, we just ignore it

-     * and treat it like a proper close.

-     */

-    sshfwd_close(pr->c);

-    x11_close(pr->s);

-    return 1;

-}

-

-static int x11_receive(Plug plug, int urgent, char *data, int len)

-{

-    struct X11Private *pr = (struct X11Private *) plug;

-

-    if (sshfwd_write(pr->c, data, len) > 0) {

-	pr->throttled = 1;

-	sk_set_frozen(pr->s, 1);

-    }

-

-    return 1;

-}

-

-static void x11_sent(Plug plug, int bufsize)

-{

-    struct X11Private *pr = (struct X11Private *) plug;

-

-    sshfwd_unthrottle(pr->c, bufsize);

-}

-

-/*

- * When setting up X forwarding, we should send the screen number

- * from the specified local display. This function extracts it from

- * the display string.

- */

-int x11_get_screen_number(char *display)

-{

-    int n;

-

-    n = strcspn(display, ":");

-    if (!display[n])

-	return 0;

-    n = strcspn(display, ".");

-    if (!display[n])

-	return 0;

-    return atoi(display + n + 1);

-}

-

-/*

- * Called to set up the raw connection.

- * 

- * Returns an error message, or NULL on success.

- * also, fills the SocketsStructure

- */

-extern const char *x11_init(Socket *s, struct X11Display *disp, void *c,

-			    const char *peeraddr, int peerport,

-			    const Config *cfg)

-{

-    static const struct plug_function_table fn_table = {

-	x11_log,

-	x11_closing,

-	x11_receive,

-	x11_sent,

-	NULL

-    };

-

-    const char *err;

-    struct X11Private *pr;

-

-    /*

-     * Open socket.

-     */

-    pr = snew(struct X11Private);

-    pr->fn = &fn_table;

-    pr->auth_protocol = NULL;

-    pr->disp = disp;

-    pr->verified = 0;

-    pr->data_read = 0;

-    pr->throttled = pr->throttle_override = 0;

-    pr->c = c;

-

-    pr->s = *s = new_connection(sk_addr_dup(disp->addr),

-				disp->realhost, disp->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);

-    return NULL;

-}

-

-void x11_close(Socket s)

-{

-    struct X11Private *pr;

-    if (!s)

-	return;

-    pr = (struct X11Private *) sk_get_private_ptr(s);

-    if (pr->auth_protocol) {

-	sfree(pr->auth_protocol);

-	sfree(pr->auth_data);

-    }

-

-    sfree(pr);

-

-    sk_close(s);

-}

-

-void x11_unthrottle(Socket s)

-{

-    struct X11Private *pr;

-    if (!s)

-	return;

-    pr = (struct X11Private *) sk_get_private_ptr(s);

-

-    pr->throttled = 0;

-    sk_set_frozen(s, pr->throttled || pr->throttle_override);

-}

-

-void x11_override_throttle(Socket s, int enable)

-{

-    struct X11Private *pr;

-    if (!s)

-	return;

-    pr = (struct X11Private *) sk_get_private_ptr(s);

-

-    pr->throttle_override = enable;

-    sk_set_frozen(s, pr->throttled || pr->throttle_override);

-}

-

-/*

- * Called to send data down the raw connection.

- */

-int x11_send(Socket s, char *data, int len)

-{

-    struct X11Private *pr;

-    if (!s)

-	return 0;

-    pr = (struct X11Private *) sk_get_private_ptr(s);

-

-    /*

-     * Read the first packet.

-     */

-    while (len > 0 && pr->data_read < 12)

-	pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++);

-    if (pr->data_read < 12)

-	return 0;

-

-    /*

-     * If we have not allocated the auth_protocol and auth_data

-     * strings, do so now.

-     */

-    if (!pr->auth_protocol) {

-	pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6);

-	pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8);

-	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 = snewn(pr->auth_psize + 1, char);

-	pr->auth_data = snewn(pr->auth_dsize, unsigned char);

-    }

-

-    /*

-     * Read the auth_protocol and auth_data strings.

-     */

-    while (len > 0 && pr->data_read < 12 + pr->auth_psize)

-	pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++);

-    while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)

-	pr->auth_data[pr->data_read++ - 12 -

-		      pr->auth_psize] = (unsigned char) (len--, *data++);

-    if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)

-	return 0;

-

-    /*

-     * If we haven't verified the authorisation, do so now.

-     */

-    if (!pr->verified) {

-	char *err;

-

-	pr->auth_protocol[pr->auth_plen] = '\0';	/* ASCIZ */

-	err = x11_verify(pr->peer_ip, pr->peer_port,

-			 pr->disp, pr->auth_protocol,

-			 pr->auth_data, pr->auth_dlen);

-

-	/*

-	 * If authorisation failed, construct and send an error

-	 * packet, then terminate the connection.

-	 */

-	if (err) {

-	    char *message;

-	    int msglen, msgsize;

-	    unsigned char *reply;

-

-	    message = dupprintf("%s X11 proxy: %s", appname, 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, (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 fake auth data, and optionally put real auth data in

-	 * instead.

-	 */

-        {

-            char realauthdata[64];

-            int realauthlen = 0;

-            int authstrlen = strlen(x11_authnames[pr->disp->localauthproto]);

-	    int buflen = 0;	       /* initialise to placate optimiser */

-            static const char zeroes[4] = { 0,0,0,0 };

-	    void *buf;

-

-            if (pr->disp->localauthproto == X11_MIT) {

-                assert(pr->disp->localauthdatalen <= lenof(realauthdata));

-                realauthlen = pr->disp->localauthdatalen;

-                memcpy(realauthdata, pr->disp->localauthdata, realauthlen);

-            } else if (pr->disp->localauthproto == X11_XDM &&

-		       pr->disp->localauthdatalen == 16 &&

-		       ((buf = sk_getxdmdata(s, &buflen))!=0)) {

-		time_t t;

-                realauthlen = (buflen+12+7) & ~7;

-		assert(realauthlen <= lenof(realauthdata));

-		memset(realauthdata, 0, realauthlen);

-		memcpy(realauthdata, pr->disp->localauthdata, 8);

-		memcpy(realauthdata+8, buf, buflen);

-		t = time(NULL);

-		PUT_32BIT_MSB_FIRST(realauthdata+8+buflen, t);

-		des_encrypt_xdmauth(pr->disp->localauthdata+9,

-				    (unsigned char *)realauthdata,

-				    realauthlen);

-		sfree(buf);

-	    }

-            /* 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->disp->localauthproto],

-			 authstrlen);

-                sk_write(s, zeroes, 3 & (-authstrlen));

-            }

-            if (realauthlen) {

-                sk_write(s, realauthdata, realauthlen);

-                sk_write(s, zeroes, 3 & (-realauthlen));

-            }

-        }

-	pr->verified = 1;

-    }

-

-    /*

-     * After initialisation, just copy data simply.

-     */

-

-    return sk_write(s, data, len);

-}