From 2014fad3d28090b59d2f8a0971166c06e5fa6da6 Mon Sep 17 00:00:00 2001
From: Hongxu Jia <hongxu.jia@windriver.com>
Date: Fri, 18 Oct 2019 14:56:58 +0800
Subject: [PATCH] upstream: fix integer overflow in XMSS private key parsing.

Reported by Adam Zabrocki via SecuriTeam's SSH program.

Note that this code is experimental and not compiled by default.

ok markus@

OpenBSD-Commit-ID: cd0361896d15e8a1bac495ac583ff065ffca2be1

Signed-off-by: "djm@openbsd.org" <djm@openbsd.org>

Upstream-Status: Backport [https://github.com/openssh/openssh-portable/commit/a546b17bbaeb12beac4c9aeed56f74a42b18a93a]
CVE: CVE-2019-16905

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 sshkey-xmss.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sshkey-xmss.c b/sshkey-xmss.c
index aaae702..c57681a 100644
--- a/sshkey-xmss.c
+++ b/sshkey-xmss.c
@@ -977,7 +977,8 @@ sshkey_xmss_decrypt_state(const struct sshkey *k, struct sshbuf *encoded,
 		goto out;
 	}
 	/* check that an appropriate amount of auth data is present */
-	if (sshbuf_len(encoded) < encrypted_len + authlen) {
+	if (sshbuf_len(encoded) < authlen ||
+	    sshbuf_len(encoded) - authlen < encrypted_len) {
 		r = SSH_ERR_INVALID_FORMAT;
 		goto out;
 	}
-- 
2.7.4