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

From: Alexander Holler
Date: Thu Jun 06 2013 - 07:18:24 EST

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@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

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:

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.


Alexander Holler
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at