Re: [PATCH RESEND/V2] crypto: Ignore validity dates of X.509 certificates at loading/parsing time

[Alexander Holler <holler@ahsoftware.de>]

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