From: simon <simon@cda61777-01e9-0310-a592-d414129be87e>
Date: Sat, 26 Oct 2002 11:23:15 +0000 (+0000)
Subject: X forwarding authentication is now invented on a per-SSH-connection
X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/commitdiff_plain/302121de61648a0aeacf28311cbee194c49f38ff

X forwarding authentication is now invented on a per-SSH-connection
basis, so the statics are gone from x11fwd.c.


git-svn-id: svn://svn.tartarus.org/sgt/putty@2145 cda61777-01e9-0310-a592-d414129be87e
---

diff --git a/ssh.c b/ssh.c
index d158d53b..d713ccf0 100644
--- a/ssh.c
+++ b/ssh.c
@@ -312,10 +312,10 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
 
 typedef struct ssh_tag *Ssh;
 
-extern char *x11_init(Socket *, char *, void *);
+extern char *x11_init(Socket *, char *, void *, void *);
 extern void x11_close(Socket);
 extern int x11_send(Socket, char *, int);
-extern void x11_invent_auth(char *, int, char *, int);
+extern void *x11_invent_auth(char *, int, char *, int);
 extern void x11_unthrottle(Socket s);
 extern void x11_override_throttle(Socket s, int enable);
 
@@ -628,6 +628,8 @@ struct ssh_tag {
     char *portfwd_strptr;
     int pkt_ctx;
 
+    void *x11auth;
+
     int version;
     int v1_throttle_count;
     int overall_bufsize;
@@ -3030,7 +3032,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     if (cfg.x11_forward) {
 	char proto[20], data[64];
 	logevent("Requesting X11 forwarding");
-	x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
+	ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
+				       data, sizeof(data));
 	if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
 	    send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
 			PKT_STR, proto, PKT_STR, data,
@@ -3273,7 +3276,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		    c = smalloc(sizeof(struct ssh_channel));
 		    c->ssh = ssh;
 
-		    if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) {
+		    if (x11_init(&c->u.x11.s, cfg.x11_display, c,
+				 ssh->x11auth) != NULL) {
 			logevent("opening X11 forward connection failed");
 			sfree(c);
 			send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
@@ -5057,7 +5061,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     if (cfg.x11_forward) {
 	char proto[20], data[64];
 	logevent("Requesting X11 forwarding");
-	x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
+	ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
+				       data, sizeof(data));
 	ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
 	ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
 	ssh2_pkt_addstring(ssh, "x11-req");
@@ -5703,8 +5708,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		if (typelen == 3 && !memcmp(type, "x11", 3)) {
 		    if (!ssh->X11_fwd_enabled)
 			error = "X11 forwarding is not enabled";
-		    else if (x11_init(&c->u.x11.s, cfg.x11_display, c) !=
-			     NULL) {
+		    else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
+				      ssh->x11auth) != NULL) {
 			error = "Unable to open an X11 connection";
 		    } else {
 			c->type = CHAN_X11;
@@ -5869,6 +5874,7 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->deferred_size = 0;
     ssh->fallback_cmd = 0;
     ssh->pkt_ctx = 0;
+    ssh->x11auth = NULL;
     ssh->v2_outgoing_sequence = 0;
     ssh->ssh1_rdpkt_crstate = 0;
     ssh->ssh2_rdpkt_crstate = 0;
diff --git a/x11fwd.c b/x11fwd.c
index 6f7be40a..033184b2 100644
--- a/x11fwd.c
+++ b/x11fwd.c
@@ -51,10 +51,16 @@
 #define PUT_16BIT(endian, cp, val) \
   (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
 
+struct X11Auth {
+    unsigned char data[64];
+    int len;
+};
+
 struct X11Private {
-    struct plug_function_table *fn;
+    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;
@@ -66,35 +72,36 @@ struct X11Private {
 
 void x11_close(Socket s);
 
-static unsigned char x11_authdata[64];
-static int x11_authdatalen;
-
-void x11_invent_auth(char *proto, int protomaxlen,
+void *x11_invent_auth(char *proto, int protomaxlen,
 		     char *data, int datamaxlen)
 {
+    struct X11Auth *auth = smalloc(sizeof(struct X11Auth));
     char ourdata[64];
     int i;
 
     /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
-    x11_authdatalen = 16;
+    auth->len = 16;
     for (i = 0; i < 16; i++)
-	x11_authdata[i] = random_byte();
+	auth->data[i] = random_byte();
 
     /* Now format for the recipient. */
     strncpy(proto, "MIT-MAGIC-COOKIE-1", protomaxlen);
     ourdata[0] = '\0';
-    for (i = 0; i < x11_authdatalen; i++)
-	sprintf(ourdata + strlen(ourdata), "%02x", x11_authdata[i]);
+    for (i = 0; i < auth->len; i++)
+	sprintf(ourdata + strlen(ourdata), "%02x", auth->data[i]);
     strncpy(data, ourdata, datamaxlen);
+
+    return auth;
 }
 
-static int x11_verify(char *proto, unsigned char *data, int dlen)
+static int x11_verify(struct X11Auth *auth,
+		      char *proto, unsigned char *data, int dlen)
 {
     if (strcmp(proto, "MIT-MAGIC-COOKIE-1") != 0)
 	return 0;		       /* wrong protocol attempted */
-    if (dlen != x11_authdatalen)
+    if (dlen != auth->len)
 	return 0;		       /* cookie was wrong length */
-    if (memcmp(x11_authdata, data, dlen) != 0)
+    if (memcmp(auth->data, data, dlen) != 0)
 	return 0;		       /* cookie was wrong cookie! */
     return 1;
 }
@@ -139,9 +146,9 @@ static void x11_sent(Plug plug, int bufsize)
  * Returns an error message, or NULL on success.
  * also, fills the SocketsStructure
  */
-char *x11_init(Socket * s, char *display, void *c)
+char *x11_init(Socket * s, char *display, void *c, void *auth)
 {
-    static struct plug_function_table fn_table = {
+    static const struct plug_function_table fn_table = {
 	x11_closing,
 	x11_receive,
 	x11_sent,
@@ -183,6 +190,7 @@ char *x11_init(Socket * s, char *display, void *c)
     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;
@@ -287,7 +295,8 @@ int x11_send(Socket s, char *data, int len)
 	int ret;
 
 	pr->auth_protocol[pr->auth_plen] = '\0';	/* ASCIZ */
-	ret = x11_verify(pr->auth_protocol, pr->auth_data, pr->auth_dlen);
+	ret = x11_verify(pr->auth, pr->auth_protocol,
+			 pr->auth_data, pr->auth_dlen);
 
 	/*
 	 * If authentication failed, construct and send an error