From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753116Ab0CWC35 (ORCPT ); Mon, 22 Mar 2010 22:29:57 -0400 Received: from qw-out-2122.google.com ([74.125.92.24]:37802 "EHLO qw-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952Ab0CWC3y convert rfc822-to-8bit (ORCPT ); Mon, 22 Mar 2010 22:29:54 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=bsq/EDWfb4eUbuAdE+yT0UjvQbCpJECUSSqlUck0+Lcgy84LvQ6vZtNUm+xNj36GHp QA3PVTTY0j3PcKthxv7bDxlTJtqF3yu0oT2ygascRmijQqdL2U/l3fq4vZSG1YAqZKW2 GxX83lptTo83o6H7ShrsfXaJPFApxHHeq994Q= MIME-Version: 1.0 In-Reply-To: <628d1651003221834g543e3e6cl4ea39c0886cb4ba1@mail.gmail.com> References: <20100320143240.GB2942@localhost.localdomain> <4BA7A3CF.8070503@trash.net> <628d1651003221834g543e3e6cl4ea39c0886cb4ba1@mail.gmail.com> Date: Tue, 23 Mar 2010 10:29:53 +0800 Message-ID: <7b6bb4a51003221929i16673523nd5f558ccbaace397@mail.gmail.com> Subject: Re: [PATCH] Netfilter: Fix integer overflow in net/ipv6/netfilter/ip6_tables.c From: Xiaotian Feng To: wzt wzt Cc: Patrick McHardy , linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 23, 2010 at 9:34 AM, wzt wzt wrote: >> I can see that the size might cause an overflow in the addition with >> sizeof(struct ipt_get_entries) > That's the integer overflow i pointed. > get.size is copy from the user space,  it can be set as 0x7fffffff, > addition with sizeof(struct ipt_get_entries) can be overflow. Patrick's point is that you're using "if (get.size >= INT_MAX / sizeof(struct ipt_get_entries))" So, did you find any chance that get.size * sizeof(struct ipt_get_entries) >= INT_MAX ? And, for the addition overflow, can it be caught by "if (*len != sizeof(struct ipt_get_entries) + get.size)" ??? > >        if (*len != sizeof(struct ipt_get_entries) + get.size) { >                duprintf("get_entries: %u != %zu\n", >                         *len, sizeof(get) + get.size); >                return -EINVAL; >        } > > so, check get.size max value before addition with sizeof(struct > ipt_get_entries) to prevent the integer overflow. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > Please read the FAQ at  http://www.tux.org/lkml/ >