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From: Stephen Hemminger <stephen@networkplumber.org>
To: "Hu, Jiayu" <jiayu.hu@intel.com>
Cc: "Richardson, Bruce" <bruce.richardson@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>, "Bie, Tiwei" <tiwei.bie@intel.com>,
	"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [PATCH] gro: fix overflow of TCP Options length calculation
Date: Mon, 7 Jan 2019 22:19:18 -0800	[thread overview]
Message-ID: <20190107221918.1db62f1b@hermes.lan> (raw)
In-Reply-To: <ED946F0BEFE0A141B63BABBD629A2A9B3CF3E117@shsmsx102.ccr.corp.intel.com>

On Tue, 8 Jan 2019 01:22:18 +0000
"Hu, Jiayu" <jiayu.hu@intel.com> wrote:

> > -----Original Message-----
> > From: Richardson, Bruce
> > Sent: Monday, January 7, 2019 10:30 PM
> > To: Hu, Jiayu <jiayu.hu@intel.com>
> > Cc: dev@dpdk.org; Bie, Tiwei <tiwei.bie@intel.com>; stable@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH] gro: fix overflow of TCP Options length
> > calculation
> > 
> > On Fri, Jan 04, 2019 at 09:57:16AM +0800, Jiayu Hu wrote:  
> > > If we receive a packet with an invalid TCP header, whose
> > > TCP header length is less than 20 bytes (the minimal TCP
> > > header length), the calculated TCP Options length will
> > > overflow and result in incorrect reassembly behaviors.  
> > 
> > Please explain how changing the "len" type fixes this behaviour.  
> 
> Originally, 'uint16_t len = RTE_MAX(tcp_hl, tcp_hl_orig) - sizeof(struct tcp_hdr)'.
> When the TCP header length of an input packet is less than 20, which is the value of
> sizeof(struct tcp_hdr), the value of len will overflow. For example, if TCP header lengths
> of input packets are 14, the value of 'len' will be 65529 (65535-6). After then, we will
> compare TCP options via memcmp(tcp_hdr+1,..., len), which would cause segment fault.

For future safety, GRO should check header lengths for IP and TCP before looking
at packet. It is basic structure hygiene

  reply	other threads:[~2019-01-08  6:19 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-04  1:57 [PATCH] gro: fix overflow of TCP Options length calculation Jiayu Hu
2019-01-07 14:29 ` Bruce Richardson
2019-01-08  1:22   ` Hu, Jiayu
2019-01-08  6:19     ` Stephen Hemminger [this message]
2019-01-08  6:08 ` [PATCH] gro: add missing invalid packet checks Jiayu Hu
2019-01-08  6:31   ` Stephen Hemminger
2019-01-08  8:14     ` Hu, Jiayu
2019-01-08 10:39       ` Ananyev, Konstantin
2019-01-08 11:33         ` Morten Brørup
2019-01-08 13:40           ` Hu, Jiayu
2019-01-08 13:43           ` Ananyev, Konstantin
2019-01-08 14:50             ` Morten Brørup
2019-01-09  3:32               ` Hu, Jiayu
2019-01-10 15:06   ` [PATCH v2] " Jiayu Hu
2019-01-14 22:26     ` [dpdk-stable] " Thomas Monjalon
2019-01-15  1:00     ` Stephen Hemminger
2019-01-15  2:48       ` Hu, Jiayu
2019-01-15  5:05     ` Wang, Yinan
2019-01-15 10:11       ` Ananyev, Konstantin
2019-01-15 12:18         ` Hu, Jiayu
2019-01-15 13:38         ` Hu, Jiayu
2019-01-16  0:45     ` [PATCH v3] gro: add missing invalid TCP header length check Jiayu Hu
2019-01-16  9:49       ` Ananyev, Konstantin
2019-01-17 21:41         ` Thomas Monjalon

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