Message-ID: <1431975679.621.40.camel@edumazet-glaptop2.roam.corp.google.com>
Subject: Re: [PATCH net-next] tcp: Return error instead of partial read for
 saved syn headers
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: Eric B Munson <emunson@akamai.com>, David Miller <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        James Morris <jmorris@namei.org>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Patrick McHardy <kaber@trash.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date: Mon, 18 May 2015 12:01:19 -0700
In-Reply-To: <555A3264.3060205@hp.com>
References: <1431974158-28288-1-git-send-email-emunson@akamai.com>
	 <555A3264.3060205@hp.com>
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On Mon, 2015-05-18 at 11:41 -0700, Rick Jones wrote:
> On 05/18/2015 11:35 AM, Eric B Munson wrote:
> > Currently the getsockopt() requesting the cached contents of the syn
> > packet headers will fail silently if the caller uses a buffer that is
> > too small to contain the requested data.  Rather than fail silently and
> > discard the headers, getsockopt() should return an error and report the
> > required size to hold the data.
> 
> Is there any chapter and verse on whether a "failed" getsockopt() may 
> alter the items passed to it?

This should be fine.

getsockopt() has two copyout to perform, the second one can fail.

We can not 'undo' the first one in a safe way.


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