Subject: Re: stable-security kernel updates
To: Greg KH <greg@kroah.com>
References: <5717DD8A.4000707@oracle.com> <571876AB.2060106@suse.cz>
 <20160421071157.GC9359@1wt.eu> <5718B92B.3080105@oracle.com>
 <20160421123631.GA19248@kroah.com>
Cc: Willy Tarreau <w@1wt.eu>, Jiri Slaby <jslaby@suse.cz>,
        LKML <linux-kernel@vger.kernel.org>, stable <stable@vger.kernel.org>,
        lwn@lwn.net
From: Sasha Levin <sasha.levin@oracle.com>
Message-ID: <5718DD39.40808@oracle.com>
Date: Thu, 21 Apr 2016 10:01:29 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.6.0
MIME-Version: 1.0
In-Reply-To: <20160421123631.GA19248@kroah.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1618
Lines: 44

On 04/21/2016 08:36 AM, Greg KH wrote:
> On Thu, Apr 21, 2016 at 07:27:39AM -0400, Sasha Levin wrote:
>> Hey Willy,
>>
>> On 04/21/2016 03:11 AM, Willy Tarreau wrote:
>>> This illustrates exactly what I suspected would happen because that's the
>>> same trouble we all face when picking backports for our respective trees
>>> except that since the selection barrier is much higher here, lots of
>>> important ones will be missing
>>
>> Right. I fully agree that there will be important security commits that'll
>> get missed, whether because they were missed in the stable selection or
>> the stable-security selection.
>>
>> I'd like to point out again that updating the entire stable tree is the
>> preferable way to patch against security (and non-security) issues.
> 
> s/preferable/only/ :)

Really? Even though as I showed updating your stable tree religiously would
still leave you vulnerable to "ancient" privesc exploits?

If anything, the *only* way is updating the entire kernel tree.

>> The
>> stable-security tree is a best-effort solution to provide a stop-gap in
>> between said stable tree updates.
> 
> What are you "stop-gapping" then?  The 7-10 days between stable
> releases?

In a perfect world where everyone has a team of kernel hackers on hand
reviewing stable commits, verifying the resulting kernel doesn't regress
their product, and fixes existing regressions for their product it might
be 7-10 days.

In the real world, this process takes much longer.

Doing a full rebase of the kernel tree is a much more costly process than
cherry picking a handful of security commits.


Thanks,
Sasha