diff -up openssh-5.5p1/channels.c.x11 openssh-5.5p1/channels.c
--- openssh-5.5p1/channels.c.x11	2010-06-30 15:22:45.000000000 +0200
+++ openssh-5.5p1/channels.c	2010-06-30 15:27:42.000000000 +0200
@@ -3332,7 +3332,7 @@ x11_create_display_inet(int x11_display_
 }
 
 static int
-connect_local_xsocket_path(const char *pathname)
+connect_local_xsocket_path(const char *pathname, int len)
 {
 	int sock;
 	struct sockaddr_un addr;
@@ -3342,7 +3342,11 @@ connect_local_xsocket_path(const char *p
 		error("socket: %.100s", strerror(errno));
 	memset(&addr, 0, sizeof(addr));
 	addr.sun_family = AF_UNIX;
-	strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
+	if (len <= 0)
+		return -1;
+	if (len > sizeof addr.sun_path)
+		len = sizeof addr.sun_path;
+	memcpy(addr.sun_path, pathname , len);
 	if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
 		return sock;
 	close(sock);
@@ -3354,8 +3358,18 @@ static int
 connect_local_xsocket(u_int dnr)
 {
 	char buf[1024];
-	snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
-	return connect_local_xsocket_path(buf);
+	int len;
+#ifdef linux
+	int ret;
+#endif
+	len = snprintf(buf + 1, sizeof (buf) - 1, _PATH_UNIX_X, dnr);
+#ifdef linux
+	/* try abstract socket first */
+	buf[0] = '\0';
+	if ((ret = connect_local_xsocket_path(buf, len + 1)) >= 0)
+		return ret;
+#endif
+	return connect_local_xsocket_path(buf + 1, len);
 }
 
 int