[u/mdw/putty] / x11fwd.c

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#include "putty.h"
#include "ssh.h"

#define GET_32BIT_LSB_FIRST(cp) \
  (((unsigned long)(unsigned char)(cp)[0]) | \
  ((unsigned long)(unsigned char)(cp)[1] << 8) | \
  ((unsigned long)(unsigned char)(cp)[2] << 16) | \
  ((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 )

#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 )

#define GET_32BIT_MSB_FIRST(cp) \
  (((unsigned long)(unsigned char)(cp)[0] << 24) | \
  ((unsigned long)(unsigned char)(cp)[1] << 16) | \
  ((unsigned long)(unsigned char)(cp)[2] << 8) | \
  ((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) )

#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) )

#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"
};

struct X11Auth {
    unsigned char fakedata[64], realdata[64];
    int fakeproto, realproto;
    int fakelen, reallen;
};

extern void platform_get_x11_auth(char *display, int *proto,
                                  unsigned char *data, int *datalen);

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 X11Auth *auth;
    char *auth_protocol;
    unsigned char *auth_data;
    int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;
    int verified;
    int throttled, throttle_override;
    void *c;			       /* data used by ssh.c */
    Socket s;
};

void *x11_invent_auth(char *proto, int protomaxlen,
		     char *data, int datamaxlen)
{
    struct X11Auth *auth = smalloc(sizeof(struct X11Auth));
    char ourdata[64];
    int i;

    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();

    /* Now format for the recipient. */
    strncpy(proto, x11_authnames[auth->fakeproto], protomaxlen);
    ourdata[0] = '\0';
    for (i = 0; i < auth->fakelen; i++)
	sprintf(ourdata + strlen(ourdata), "%02x", auth->fakedata[i]);
    strncpy(data, ourdata, datamaxlen);

    return auth;
}

/*
 * 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 int x11_verify(struct X11Auth *auth,
		      char *proto, unsigned char *data, int dlen)
{
    if (strcmp(proto, x11_authnames[auth->fakeproto]) != 0)
	return 0;		       /* wrong protocol attempted */
    if (auth->fakeproto == X11_MIT) {
        if (dlen != auth->fakelen)
            return 0;		       /* cookie was wrong length */
        if (memcmp(auth->fakedata, data, dlen) != 0)
            return 0;		       /* cookie was wrong cookie! */
    }
    /* implement other protocols here if ever required */
    return 1;
}

static int x11_closing(Plug plug, 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
 */
char *x11_init(Socket * s, char *display, void *c, void *auth)
{
    static const struct plug_function_table fn_table = {
	x11_closing,
	x11_receive,
	x11_sent,
	NULL
    };

    SockAddr addr;
    int port;
    char *err, *dummy_realhost;
    char host[128];
    int n, displaynum;
    struct X11Private *pr;

    /*
     * Split up display name into host and display-number parts.
     */
    n = strcspn(display, ":");
    if (display[n])
	displaynum = atoi(display + n + 1);
    else
	displaynum = 0;		       /* sensible default */
    if (n > sizeof(host) - 1)
	n = sizeof(host) - 1;
    if (n > 0) {
	strncpy(host, display, n);
	host[n] = '\0';
    } else {
	/*
	 * Local display numbers, particularly on Unix, often omit
	 * the display part completely.
	 */
	strcpy(host, "localhost");
    }

    port = 6000 + displaynum;

    /*
     * Try to find host.
     */
    addr = name_lookup(host, port, &dummy_realhost);
    if ((err = sk_addr_error(addr)) != NULL)
	return err;

    /*
     * Open socket.
     */
    pr = (struct X11Private *) smalloc(sizeof(struct X11Private));
    pr->fn = &fn_table;
    pr->auth_protocol = NULL;
    pr->auth = (struct X11Auth *)auth;
    pr->verified = 0;
    pr->data_read = 0;
    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)) != NULL) {
	sfree(pr);
	return err;
    }

    sk_set_private_ptr(*s, pr);
    sk_addr_free(addr);
    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 = (struct X11Private *) sk_get_private_ptr(s);

    if (s == NULL)
	return 0;

    /*
     * 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 = (char *) smalloc(pr->auth_psize + 1);
	pr->auth_data = (unsigned char *) smalloc(pr->auth_dsize);
    }

    /*
     * 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 authentication, do so now.
     */
    if (!pr->verified) {
	int ret;

	pr->auth_protocol[pr->auth_plen] = '\0';	/* ASCIZ */
	ret = x11_verify(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;
	    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);
	    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->auth->realproto]);
            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);
            }
            /* 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;
    }

    /*
     * After initialisation, just copy data simply.
     */

    return sk_write(s, data, len);
}
Commit	Line	Data
9c964e85	1	#include <stdio.h>
9c964e85	2	#include <stdlib.h>
e0e7dff8	3	#include <assert.h>
9c964e85	4
	5	#include "putty.h"
	6	#include "ssh.h"
	7
9c964e85	8	#define GET_32BIT_LSB_FIRST(cp) \
	9	(((unsigned long)(unsigned char)(cp)[0]) \| \
	10	((unsigned long)(unsigned char)(cp)[1] << 8) \| \
	11	((unsigned long)(unsigned char)(cp)[2] << 16) \| \
	12	((unsigned long)(unsigned char)(cp)[3] << 24))
	13
	14	#define PUT_32BIT_LSB_FIRST(cp, value) ( \
	15	(cp)[0] = (value), \
	16	(cp)[1] = (value) >> 8, \
	17	(cp)[2] = (value) >> 16, \
	18	(cp)[3] = (value) >> 24 )
	19
	20	#define GET_16BIT_LSB_FIRST(cp) \
	21	(((unsigned long)(unsigned char)(cp)[0]) \| \
	22	((unsigned long)(unsigned char)(cp)[1] << 8))
	23
	24	#define PUT_16BIT_LSB_FIRST(cp, value) ( \
	25	(cp)[0] = (value), \
	26	(cp)[1] = (value) >> 8 )
	27
	28	#define GET_32BIT_MSB_FIRST(cp) \
	29	(((unsigned long)(unsigned char)(cp)[0] << 24) \| \
	30	((unsigned long)(unsigned char)(cp)[1] << 16) \| \
	31	((unsigned long)(unsigned char)(cp)[2] << 8) \| \
	32	((unsigned long)(unsigned char)(cp)[3]))
	33
	34	#define PUT_32BIT_MSB_FIRST(cp, value) ( \
	35	(cp)[0] = (value) >> 24, \
	36	(cp)[1] = (value) >> 16, \
	37	(cp)[2] = (value) >> 8, \
	38	(cp)[3] = (value) )
	39
	40	#define GET_16BIT_MSB_FIRST(cp) \
	41	(((unsigned long)(unsigned char)(cp)[0] << 8) \| \
	42	((unsigned long)(unsigned char)(cp)[1]))
	43
	44	#define PUT_16BIT_MSB_FIRST(cp, value) ( \
	45	(cp)[0] = (value) >> 8, \
	46	(cp)[1] = (value) )
	47
	48	#define GET_16BIT(endian, cp) \
	49	(endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))
	50
	51	#define PUT_16BIT(endian, cp, val) \
	52	(endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
	53
e0e7dff8	54	const char *const x11_authnames[] = {
	55	"", "MIT-MAGIC-COOKIE-1"
	56	};
	57
302121de	58	struct X11Auth {
e0e7dff8	59	unsigned char fakedata[64], realdata[64];
	60	int fakeproto, realproto;
	61	int fakelen, reallen;
302121de	62	};
302121de	63
e0e7dff8	64	extern void platform_get_x11_auth(char display, int proto,
	65	unsigned char data, int datalen);
	66
9c964e85	67	struct X11Private {
302121de	68	const struct plug_function_table *fn;
7e78000d	69	/* the above variable absolutely must be the first in this structure */
32874aea	70	unsigned char firstpkt[12]; /* first X data packet */
302121de	71	struct X11Auth *auth;
9c964e85	72	char *auth_protocol;
	73	unsigned char *auth_data;
	74	int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;
	75	int verified;
5471d09a	76	int throttled, throttle_override;
32874aea	77	void c; / data used by ssh.c */
7e78000d	78	Socket s;
9c964e85	79	};
9c964e85	80
302121de	81	void x11_invent_auth(char proto, int protomaxlen,
32874aea	82	char *data, int datamaxlen)
32874aea	83	{
302121de	84	struct X11Auth *auth = smalloc(sizeof(struct X11Auth));
9c964e85	85	char ourdata[64];
	86	int i;
	87
e0e7dff8	88	auth->fakeproto = X11_MIT;
e0e7dff8	89
9c964e85	90	/* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
e0e7dff8	91	auth->fakelen = 16;
9c964e85	92	for (i = 0; i < 16; i++)
e0e7dff8	93	auth->fakedata[i] = random_byte();
9c964e85	94
9c964e85	95	/* Now format for the recipient. */
e0e7dff8	96	strncpy(proto, x11_authnames[auth->fakeproto], protomaxlen);
9c964e85	97	ourdata[0] = '\0';
e0e7dff8	98	for (i = 0; i < auth->fakelen; i++)
e0e7dff8	99	sprintf(ourdata + strlen(ourdata), "%02x", auth->fakedata[i]);
9c964e85	100	strncpy(data, ourdata, datamaxlen);
302121de	101
302121de	102	return auth;
9c964e85	103	}
9c964e85	104
e0e7dff8	105	/*
	106	* Fetch the real auth data for a given display string, and store
	107	* it in an X11Auth structure. Returns NULL on success, or an error
	108	* string.
	109	*/
	110	void x11_get_real_auth(void authv, char display)
	111	{
	112	struct X11Auth auth = (struct X11Auth )authv;
	113
	114	auth->realproto = X11_NO_AUTH; /* in case next call does nothing */
	115
	116	auth->reallen = sizeof(auth->realdata);
	117	platform_get_x11_auth(display, &auth->realproto,
	118	auth->realdata, &auth->reallen);
	119	}
	120
302121de	121	static int x11_verify(struct X11Auth *auth,
302121de	122	char proto, unsigned char data, int dlen)
32874aea	123	{
e0e7dff8	124	if (strcmp(proto, x11_authnames[auth->fakeproto]) != 0)
32874aea	125	return 0; /* wrong protocol attempted */
e0e7dff8	126	if (auth->fakeproto == X11_MIT) {
	127	if (dlen != auth->fakelen)
	128	return 0; /* cookie was wrong length */
	129	if (memcmp(auth->fakedata, data, dlen) != 0)
	130	return 0; /* cookie was wrong cookie! */
	131	}
	132	/* implement other protocols here if ever required */
9c964e85	133	return 1;
	134	}
	135
32874aea	136	static int x11_closing(Plug plug, char *error_msg, int error_code,
	137	int calling_back)
	138	{
7e78000d	139	struct X11Private pr = (struct X11Private ) plug;
	140
	141	/*
	142	* We have no way to communicate down the forwarded connection,
	143	* so if an error occurred on the socket, we just ignore it
	144	* and treat it like a proper close.
	145	*/
	146	sshfwd_close(pr->c);
	147	x11_close(pr->s);
	148	return 1;
	149	}
	150
32874aea	151	static int x11_receive(Plug plug, int urgent, char *data, int len)
32874aea	152	{
7e78000d	153	struct X11Private pr = (struct X11Private ) plug;
9c964e85	154
5471d09a	155	if (sshfwd_write(pr->c, data, len) > 0) {
	156	pr->throttled = 1;
	157	sk_set_frozen(pr->s, 1);
	158	}
	159
9c964e85	160	return 1;
	161	}
	162
5471d09a	163	static void x11_sent(Plug plug, int bufsize)
	164	{
	165	struct X11Private pr = (struct X11Private ) plug;
	166
	167	sshfwd_unthrottle(pr->c, bufsize);
	168	}
	169
9c964e85	170	/*
421d6835	171	* When setting up X forwarding, we should send the screen number
	172	* from the specified local display. This function extracts it from
	173	* the display string.
	174	*/
	175	int x11_get_screen_number(char *display)
	176	{
	177	int n;
	178
	179	n = strcspn(display, ":");
	180	if (!display[n])
	181	return 0;
	182	n = strcspn(display, ".");
	183	if (!display[n])
	184	return 0;
	185	return atoi(display + n + 1);
	186	}
	187
	188	/*
9c964e85	189	* Called to set up the raw connection.
	190	*
	191	* Returns an error message, or NULL on success.
	192	* also, fills the SocketsStructure
9c964e85	193	*/
302121de	194	char x11_init(Socket s, char display, void c, void *auth)
32874aea	195	{
302121de	196	static const struct plug_function_table fn_table = {
7e78000d	197	x11_closing,
5471d09a	198	x11_receive,
	199	x11_sent,
	200	NULL
7e78000d	201	};
7e78000d	202
9c964e85	203	SockAddr addr;
9c964e85	204	int port;
0c6c9a70	205	char err, dummy_realhost;
9c964e85	206	char host[128];
	207	int n, displaynum;
	208	struct X11Private *pr;
	209
	210	/*
	211	* Split up display name into host and display-number parts.
	212	*/
	213	n = strcspn(display, ":");
	214	if (display[n])
32874aea	215	displaynum = atoi(display + n + 1);
9c964e85	216	else
32874aea	217	displaynum = 0; /* sensible default */
	218	if (n > sizeof(host) - 1)
	219	n = sizeof(host) - 1;
ecc0ba5b	220	if (n > 0) {
	221	strncpy(host, display, n);
	222	host[n] = '\0';
	223	} else {
	224	/*
	225	* Local display numbers, particularly on Unix, often omit
	226	* the display part completely.
	227	*/
	228	strcpy(host, "localhost");
	229	}
9c964e85	230
9f2f8ea0	231	port = 6000 + displaynum;
9f2f8ea0	232
9c964e85	233	/*
	234	* Try to find host.
	235	*/
b7a189f3	236	addr = name_lookup(host, port, &dummy_realhost);
6518ea7b	237	if ((err = sk_addr_error(addr)) != NULL)
9c964e85	238	return err;
9c964e85	239
9c964e85	240	/*
	241	* Open socket.
	242	*/
32874aea	243	pr = (struct X11Private *) smalloc(sizeof(struct X11Private));
7e78000d	244	pr->fn = &fn_table;
9c964e85	245	pr->auth_protocol = NULL;
302121de	246	pr->auth = (struct X11Auth *)auth;
9c964e85	247	pr->verified = 0;
9c964e85	248	pr->data_read = 0;
5471d09a	249	pr->throttled = pr->throttle_override = 0;
9c964e85	250	pr->c = c;
9c964e85	251
8eebd221	252	pr->s = *s = new_connection(addr, dummy_realhost, port, 0, 1, 0, (Plug) pr);
6518ea7b	253	if ((err = sk_socket_error(*s)) != NULL) {
32874aea	254	sfree(pr);
7e78000d	255	return err;
	256	}
	257
9c964e85	258	sk_set_private_ptr(*s, pr);
	259	sk_addr_free(addr);
	260	return NULL;
	261	}
	262
32874aea	263	void x11_close(Socket s)
	264	{
	265	struct X11Private *pr;
d74d141c	266	if (!s)
	267	return;
	268	pr = (struct X11Private *) sk_get_private_ptr(s);
9c964e85	269	if (pr->auth_protocol) {
32874aea	270	sfree(pr->auth_protocol);
32874aea	271	sfree(pr->auth_data);
9c964e85	272	}
	273
	274	sfree(pr);
	275
	276	sk_close(s);
	277	}
	278
5471d09a	279	void x11_unthrottle(Socket s)
	280	{
	281	struct X11Private *pr;
	282	if (!s)
	283	return;
	284	pr = (struct X11Private *) sk_get_private_ptr(s);
	285
	286	pr->throttled = 0;
	287	sk_set_frozen(s, pr->throttled \|\| pr->throttle_override);
	288	}
	289
	290	void x11_override_throttle(Socket s, int enable)
	291	{
	292	struct X11Private *pr;
	293	if (!s)
	294	return;
	295	pr = (struct X11Private *) sk_get_private_ptr(s);
	296
	297	pr->throttle_override = enable;
	298	sk_set_frozen(s, pr->throttled \|\| pr->throttle_override);
	299	}
	300
9c964e85	301	/*
	302	* Called to send data down the raw connection.
	303	*/
5471d09a	304	int x11_send(Socket s, char *data, int len)
32874aea	305	{
32874aea	306	struct X11Private pr = (struct X11Private ) sk_get_private_ptr(s);
9c964e85	307
9c964e85	308	if (s == NULL)
5471d09a	309	return 0;
9c964e85	310
	311	/*
	312	* Read the first packet.
	313	*/
	314	while (len > 0 && pr->data_read < 12)
32874aea	315	pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++);
9c964e85	316	if (pr->data_read < 12)
5471d09a	317	return 0;
9c964e85	318
	319	/*
	320	* If we have not allocated the auth_protocol and auth_data
	321	* strings, do so now.
	322	*/
	323	if (!pr->auth_protocol) {
32874aea	324	pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6);
	325	pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8);
	326	pr->auth_psize = (pr->auth_plen + 3) & ~3;
	327	pr->auth_dsize = (pr->auth_dlen + 3) & ~3;
	328	/* Leave room for a terminating zero, to make our lives easier. */
	329	pr->auth_protocol = (char *) smalloc(pr->auth_psize + 1);
f28e6b7c	330	pr->auth_data = (unsigned char *) smalloc(pr->auth_dsize);
9c964e85	331	}
	332
	333	/*
	334	* Read the auth_protocol and auth_data strings.
	335	*/
	336	while (len > 0 && pr->data_read < 12 + pr->auth_psize)
32874aea	337	pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++);
9c964e85	338	while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)
32874aea	339	pr->auth_data[pr->data_read++ - 12 -
32874aea	340	pr->auth_psize] = (unsigned char) (len--, *data++);
9c964e85	341	if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)
5471d09a	342	return 0;
9c964e85	343
	344	/*
	345	* If we haven't verified the authentication, do so now.
	346	*/
	347	if (!pr->verified) {
32874aea	348	int ret;
	349
	350	pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */
302121de	351	ret = x11_verify(pr->auth, pr->auth_protocol,
302121de	352	pr->auth_data, pr->auth_dlen);
32874aea	353
	354	/*
	355	* If authentication failed, construct and send an error
	356	* packet, then terminate the connection.
	357	*/
	358	if (!ret) {
	359	char message[] = "Authentication failed at PuTTY X11 proxy";
	360	unsigned char reply[8 + sizeof(message) + 4];
	361	int msglen = sizeof(message) - 1; /* skip zero byte */
	362	int msgsize = (msglen + 3) & ~3;
	363	reply[0] = 0; /* failure */
	364	reply[1] = msglen; /* length of reason string */
	365	memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */
75105663	366	PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */
32874aea	367	memset(reply + 8, 0, msgsize);
32874aea	368	memcpy(reply + 8, message, msglen);
f28e6b7c	369	sshfwd_write(pr->c, (char *)reply, 8 + msgsize);
32874aea	370	sshfwd_close(pr->c);
32874aea	371	x11_close(s);
5471d09a	372	return 0;
32874aea	373	}
	374
	375	/*
	376	* Now we know we're going to accept the connection. Strip
e0e7dff8	377	* the fake auth data, and optionally put real auth data in
e0e7dff8	378	* instead.
32874aea	379	*/
e0e7dff8	380	{
	381	char realauthdata[64];
	382	int realauthlen = 0;
	383	int authstrlen = strlen(x11_authnames[pr->auth->realproto]);
	384	static const char zeroes[4] = { 0,0,0,0 };
	385
	386	if (pr->auth->realproto == X11_MIT) {
	387	assert(pr->auth->reallen <= lenof(realauthdata));
	388	realauthlen = pr->auth->reallen;
	389	memcpy(realauthdata, pr->auth->realdata, realauthlen);
	390	}
	391	/* implement other auth methods here if required */
	392
	393	PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, authstrlen);
	394	PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, realauthlen);
	395
	396	sk_write(s, (char *)pr->firstpkt, 12);
	397
	398	if (authstrlen) {
	399	sk_write(s, x11_authnames[pr->auth->realproto], authstrlen);
	400	sk_write(s, zeroes, 3 & (-authstrlen));
	401	}
	402	if (realauthlen) {
	403	sk_write(s, realauthdata, realauthlen);
	404	sk_write(s, zeroes, 3 & (-realauthlen));
	405	}
	406	}
32874aea	407	pr->verified = 1;
9c964e85	408	}
	409
	410	/*
	411	* After initialisation, just copy data simply.
	412	*/
	413
5471d09a	414	return sk_write(s, data, len);
9c964e85	415	}