From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36432 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753099AbeBWSdH (ORCPT ); Fri, 23 Feb 2018 13:33:07 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+4396883fa8c4f64e0175@syzkaller.appspotmail.com, Dmitry Vyukov , Pablo Neira Ayuso Subject: [PATCH 4.4 015/193] netfilter: x_tables: fix int overflow in xt_alloc_table_info() Date: Fri, 23 Feb 2018 19:24:08 +0100 Message-Id: <20180223170328.496659583@linuxfoundation.org> In-Reply-To: <20180223170325.997716448@linuxfoundation.org> References: <20180223170325.997716448@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Vyukov commit 889c604fd0b5f6d3b8694ade229ee44124de1127 upstream. syzkaller triggered OOM kills by passing ipt_replace.size = -1 to IPT_SO_SET_REPLACE. The root cause is that SMP_ALIGN() in xt_alloc_table_info() causes int overflow and the size check passes when it should not. SMP_ALIGN() is no longer needed leftover. Remove SMP_ALIGN() call in xt_alloc_table_info(). Reported-by: syzbot+4396883fa8c4f64e0175@syzkaller.appspotmail.com Signed-off-by: Dmitry Vyukov Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/x_tables.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -38,8 +38,6 @@ MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte "); MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module"); -#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) - struct compat_delta { unsigned int offset; /* offset in kernel */ int delta; /* delta in 32bit user land */ @@ -954,7 +952,7 @@ struct xt_table_info *xt_alloc_table_inf return NULL; /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ - if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages) + if ((size >> PAGE_SHIFT) + 2 > totalram_pages) return NULL; if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))