[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <8a0c0ef3-4881-1b9c-6e42-ab379542bc16@linux.alibaba.com>
Date: Tue, 28 Apr 2020 15:07:10 +0800
From: Tianjia Zhang <tianjia.zhang@...ux.alibaba.com>
To: Greg KH <gregkh@...uxfoundation.org>
Cc: jeyu@...nel.org, corbet@....net, rdunlap@...radead.org,
mchehab+samsung@...nel.org, tglx@...utronix.de,
akpm@...ux-foundation.org, pawan.kumar.gupta@...ux.intel.com,
jgross@...e.com, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org
Subject: Re: [PATCH v3] module: Allow to disable modsign in kernel cmdline
On 2020/4/28 14:35, Greg KH wrote:
> On Tue, Apr 28, 2020 at 02:00:08PM +0800, Tianjia Zhang wrote:
>> This option allows to disable modsign completely at the beginning,
>> and turn off by set the kernel cmdline `no_modsig_enforce` when
>> `CONFIG_MODULE_SIG_FORCE` is enabled.
>>
>> Yet another change allows to always show the current status of
>> modsign through `/sys/module/module/parameters/sig_enforce`.
>>
>> Signed-off-by: Jia Zhang <zhang.jia@...ux.alibaba.com>
>> Signed-off-by: Tianjia Zhang <tianjia.zhang@...ux.alibaba.com>
>> ---
>>
>> v3 change:
>> Beautify the document description according to the recommendation.
>>
>> v2 change:
>> document this new option.
>>
>> Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>> kernel/module.c | 8 ++++++++
>> 2 files changed, 14 insertions(+)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 7bc83f3d9bdf..b30f013fb8c5 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -3190,6 +3190,12 @@
>> noirqdebug [X86-32] Disables the code which attempts to detect and
>> disable unhandled interrupt sources.
>>
>> + no_modsig_enforce
>> + [KNL] When CONFIG_MODULE_SIG_FORCE is set, this option
>> + allows to disable modsign completely at the beginning.
>> + This means that modules without (valid) signatures will
>> + be loaded successfully.
>> +
>
> So now we have module.sig_enforce and this one? That feels really
> confusing, why can't you just use the existing option?
>
> And why would you want to allow the bootloader to override a kernel
> build option like this? That feels risky.
>
> thanks,
>
> greg k-h
>
If CONFIG_MODULE_SIG_FORCE is set, `module.sig_enforce` is always true
and read-only. There is indeed a risk in doing this, but it will allow
the system to boot normally in some emergency situations, such as
certificate expiration.
On the other hand, would it be a good solution to make
`module.sig_enforce` readable and writable?
Thanks and best,
Tianjia
Powered by blists - more mailing lists