Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Sat, 22 Dec 2018 15:08:42 -0800 (PST)
Message-Id: <20181222.150842.1563344934152542563.davem@davemloft.net>
To:     gustavo@embeddedor.com
Cc:     courmisch@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] phonet: af_phonet: Fix Spectre v1 vulnerability
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20181221214117.GA1539@embeddedor>
References: <20181221214117.GA1539@embeddedor>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Fri, 21 Dec 2018 15:41:17 -0600

> protocol is indirectly controlled by user-space, hence leading to
> a potential exploitation of the Spectre variant 1 vulnerability.
> 
> This issue was detected with the help of Smatch:
> 
> net/phonet/af_phonet.c:48 phonet_proto_get() warn: potential spectre issue 'proto_tab' [w] (local cap)
> 
> Fix this by sanitizing protocol before using it to index proto_tab.
> 
> Notice that given that speculation windows are large, the policy is
> to kill the speculation on the first load and not worry if it can be
> completed with a dependent load/store [1].
> 
> [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Applied, thanks.