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SubjectRe: [PATCH] MODSIGN: Warn when sign check fails due to -ENOKEY
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On Fri, Jan 11, 2013 at 4:44 AM, Chris Samuel <chris@csamuel.org> wrote:
> /* Please CC me in responses, I am not subscribed to LKML */
>
> Currently if a signature check fails on module load due to not having
> the appropriate key (-ENOKEY) and we are not doing strict checking
> there is no information provided to the user other than the lock debug
> taint warning:
>
> Disabling lock debugging due to kernel taint
>
> This patch causes a single warning to be emitted to explain why the
> kernel is being tainted, before the above taint warning occurs.
>
> Module verification failed, required key not present, tainting kernel
>
> Found whilst trying to work out why all the 3.8 development kernels
> I was building and testing were warning about taints and why all modules
> were listed as forced load (F) in /proc/modules when that wasn't the
> case in the 3.5, 3.6 or 3.7 kernels I'd tried.
>
> Signed-off-by: Christopher Samuel <chris@csamuel.org>
> ---
> kernel/module.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 250092c..27de534 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2443,8 +2443,10 @@ static int module_sig_check(struct load_info *info)
> if (err < 0 && fips_enabled)
> panic("Module verification failed with error %d in FIPS
> mode\n",
> err);
> - if (err == -ENOKEY && !sig_enforce)
> + if (err == -ENOKEY && !sig_enforce) {
> + printk_once(KERN_DEBUG "Module verification failed, required
> key not present, tainting kernel\n");
> err = 0;
> + }
> return err;

I'd suggest putting the printk in load_module where we call the
add_taint_module function instead. Also, you might want to make the
priority a bit higher if it's meant to be informative. Something like
KERN_INFO.

josh


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