From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH  RESEND/V2] crypto: Ignore validity dates of X.509 certificates at loading/parsing time
Date: Fri, 07 Jun 2013 11:43:41 +0930
Message-ID: <87d2ryr7l6.fsf@rustcorp.com.au>
References: <1364409710-6458-1-git-send-email-holler@ahsoftware.de> <1367503746-6431-1-git-send-email-holler@ahsoftware.de> <51B06FC3.8090405@ahsoftware.de>
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Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	David Howells <dhowells@redhat.com>,
	Josh Boyer <jwboyer@redhat.com>,
	David Woodhouse <dwmw2@infradead.org>
To: Alexander Holler <holler@ahsoftware.de>,
	Alexander Holler <holler@ahsoftware.de>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <51B06FC3.8090405@ahsoftware.de>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-crypto.vger.kernel.org

Alexander Holler <holler@ahsoftware.de> writes:
> Am 02.05.2013 16:09, schrieb Alexander Holler:
>> I don't see any real use case where checking the validity dates of X.509
>> certificates at parsing time adds any security gain. In contrast, doing so
>> makes MODSIGN unusable on systems without a RTC (or systems with a possible
>> wrong date in a existing RTC, or systems where the RTC is read after the keys
>> got loaded).
>> 
>> If something really cares about the dates, it should check them at the time
>> when the certificates are used, not when they are loaded and parsed.
>> 
>> So just remove the validity check of the dates in the parser.
>> 
>> Signed-off-by: Alexander Holler <holler@ahsoftware.de>
>> Cc: stable@vger.kernel.org
>
> As it just happened to me again and I've recently posted some patches
> which do make it possible to experience the problem on x86 systems too,
> here is a reminder.
>
> To replay the problem (on x86 or any other arch), apply the 3 patches in
> this series:
>
> https://lkml.org/lkml/2013/6/5/430
>
> build a kernel with CONFIG_MODULE_SIG_FORCE=y and start that kernel with
> hctosys=none as kernel command line parameter.
>
> This will disable the "persistent" clock (and any RTC), thus the kernel
> will refuse to load modules because it doesn't has a valid time when
> loading the certificate.
>
> Regards,
>
> Alexander Holler

David?

Thanks,
Rusty.