merge 2016.72

.hgsigs

@@ -19,3 +19,4 @@ ef4b26364b0cdda1084751d7de3d76c589e2d9cb 0 iQIcBAABCgAGBQJVxg7BAAoJEESTFJTynGdz9
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+fd1981f41c626a969f07b4823848deaefef3c8aa 0 iQIcBAABCgAGBQJW4W2TAAoJEESTFJTynGdzuOcP/j6tvB2WRwSj39KoJuRcRebFWWv4ZHiQXYMXWa3X0Ppzz52r9W0cXDjjlp5FyGdovCQsK+IXmjPo5cCvWBrZJYA6usFr9ssnUtTC+45lvPxPYwj47ZGPngCXDt7LD+v08XhqCu4LsctXIP/zejd30KVS1eR2RHI+tnEyaIKC0Xaa0igcv74MZX7Q8/U+B730QMX5adfYAHoeyRhoctRWaxVV3To7Vadd9jNXP45MRY5auhRcK7XyQcS85vJeCRoysfDUas4ERRQWYkX+68GyzO9GrkYFle931Akw2K6ZZfUuiC2TrF5xv1eRP1Zm2GX481U4ZGFTI8IzZL8sVQ6tvzq2Mxsecu589JNui9aB2d8Gp2Su/E2zn0h0ShIRmviGzf2HiBt+Bnji5X2h/fJKWbLaWge0MdOU5Jidfyh9k0YT7xo4piJLJYSaZ3nv+j4jTYnTfL7uYvuWbYkJ1T32aQVCan7Eup3BFAgQjzbWYi1XQVg6fvu8uHPpS3tNNA9EAMeeyTyg1l6zI2EIU5gPfd/dKmdyotY2lZBkFZNJqFkKRZuzjWekcw7hAxS+Bd68GKklt/DGrQiVycAgimqwXrfkzzQagawq2fXL2uXB8ghlsyxKLSQPnAtBF2Jcn5FH2z7HOQ+e18ZrFfNy0cYa/4OdH6K5aK1igTzhZZP2Urn0

.hgtags

@@ -51,3 +51,4 @@ cbd674d63cd4f3781464a8d4056a5506c8ae926f DROPBEAR_2015.67
 1637dbd262124d113e52967df46afd6c715e4fad DROPBEAR_2015.69
 79a6ef02307d05cb9dda10465cb5b807baa8f62e DROPBEAR_2015.70
 9a944a243f08be6b22d32f166a0690eb4872462b DROPBEAR_2015.71
+78b12b6549be08b0bea3da329b2578060a76ca31 DROPBEAR_2016.72

CHANGES

@@ -1,3 +1,8 @@
+2016.72 - 9 March 2016
+
+- Validate X11 forwarding input. Could allow bypass of authorized_keys command= restrictions,
+  found by github.com/tintinweb. Thanks for Damien Miller for a patch.
+
 2015.71 - 3 December 2015
 
 - Fix "bad buf_incrpos" when data is transferred, broke in 2015.69

debian/changelog

@@ -1,8 +1,8 @@
-dropbear (2015.71-0.1) unstable; urgency=low
+dropbear (2016.72-0.1) unstable; urgency=low
 
   * New upstream release.
 
- -- Matt Johnston <matt@ucc.asn.au>  Thu, 3 Dec 2015 22:52:58 +0800
+ -- Matt Johnston <matt@ucc.asn.au>  Wed, 10 Mar 2016 22:52:58 +0800
 
 dropbear (2015.70-0.1) unstable; urgency=low
 

svr-x11fwd.c

@@ -42,11 +42,29 @@ static void x11accept(struct Listener* listener, int sock);
 static int bindport(int fd);
 static int send_msg_channel_open_x11(int fd, struct sockaddr_in* addr);
 
+/* Check untrusted xauth strings for metacharacters */
+/* Returns DROPBEAR_SUCCESS/DROPBEAR_FAILURE */
+static int
+xauth_valid_string(const char *s)
+{
+	size_t i;
+
+	for (i = 0; s[i] != '\0'; i++) {
+		if (!isalnum(s[i]) &&
+		    s[i] != '.' && s[i] != ':' && s[i] != '/' &&
+		    s[i] != '-' && s[i] != '_') {
+			return DROPBEAR_FAILURE;
+		}
+	}
+	return DROPBEAR_SUCCESS;
+}
+
+
 /* called as a request for a session channel, sets up listening X11 */
 /* returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
 int x11req(struct ChanSess * chansess) {
 
-	int fd;
+	int fd = -1;
 
 	if (!svr_pubkey_allows_x11fwd()) {
 		return DROPBEAR_FAILURE;
@@ -62,6 +80,11 @@ int x11req(struct ChanSess * chansess) {
 	chansess->x11authcookie = buf_getstring(ses.payload, NULL);
 	chansess->x11screennum = buf_getint(ses.payload);
 
+	if (xauth_valid_string(chansess->x11authprot) == DROPBEAR_FAILURE ||
+		xauth_valid_string(chansess->x11authcookie) == DROPBEAR_FAILURE) {
+		dropbear_log(LOG_WARNING, "Bad xauth request");
+		goto fail;
+	}
 	/* create listening socket */
 	fd = socket(PF_INET, SOCK_STREAM, 0);
 	if (fd < 0) {
@@ -159,7 +182,7 @@ void x11setauth(struct ChanSess *chansess) {
 		return;
 	}
 
-	/* popen is a nice function - code is strongly based on OpenSSH's */
+	/* code is strongly based on OpenSSH's */
 	authprog = popen(XAUTH_COMMAND, "w");
 	if (authprog) {
 		fprintf(authprog, "add %s %s %s\n",

sysoptions.h

@@ -4,7 +4,7 @@
  *******************************************************************/
 
 #ifndef DROPBEAR_VERSION
-#define DROPBEAR_VERSION "2015.71"
+#define DROPBEAR_VERSION "2016.72"
 #endif
 
 #define LOCAL_IDENT "SSH-2.0-dropbear_" DROPBEAR_VERSION