From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiaotian Feng Subject: Re: [PATCH] Netfilter: Fix integer overflow in net/ipv6/netfilter/ip6_tables.c Date: Tue, 23 Mar 2010 10:29:53 +0800 Message-ID: <7b6bb4a51003221929i16673523nd5f558ccbaace397@mail.gmail.com> References: <20100320143240.GB2942@localhost.localdomain> <4BA7A3CF.8070503@trash.net> <628d1651003221834g543e3e6cl4ea39c0886cb4ba1@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Patrick McHardy , linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org To: wzt wzt Return-path: In-Reply-To: <628d1651003221834g543e3e6cl4ea39c0886cb4ba1@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netfilter-devel.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, =C2=A0it can be set as 0x7fffff= ff, > addition with sizeof(struct ipt_get_entries) can be overflow. Patrick's point is that you're using "if (get.size >=3D INT_MAX / sizeof(struct ipt_get_entries))" So, did you find any chance that get.size * sizeof(struct ipt_get_entries) >=3D INT_MAX ? And, for the addition overflow, can it be caught by "if (*len !=3D sizeof(struct ipt_get_entries) + get.size)" ??? > > =C2=A0 =C2=A0 =C2=A0 =C2=A0if (*len !=3D sizeof(struct ipt_get_entrie= s) + get.size) { > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0duprintf("get_= entries: %u !=3D %zu\n", > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 *len, sizeof(get) + get.size); > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return -EINVAL= ; > =C2=A0 =C2=A0 =C2=A0 =C2=A0} > > 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-kerne= l" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht= ml > Please read the FAQ at =C2=A0http://www.tux.org/lkml/ >