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Date:   Tue, 18 Jun 2019 10:04:56 -0700 (PDT)
Message-Id: <20190618.100456.509667574835376076.davem@davemloft.net>
To:     houjingyi647@gmail.com
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: remove duplicate fetch in sock_getsockopt
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20190617065605.GA5924@hjy-HP-Notebook>
References: <20190617065605.GA5924@hjy-HP-Notebook>
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From: JingYi Hou <houjingyi647@gmail.com>
Date: Mon, 17 Jun 2019 14:56:05 +0800

> In sock_getsockopt(), 'optlen' is fetched the first time from userspace.
> 'len < 0' is then checked. Then in condition 'SO_MEMINFO', 'optlen' is
> fetched the second time from userspace.
> 
> If change it between two fetches may cause security problems or unexpected
> behaivor, and there is no reason to fetch it a second time.
> 
> To fix this, we need to remove the second fetch.
> 
> Signed-off-by: JingYi Hou <houjingyi647@gmail.com>

Applied and queued up for -stable, thanks.