Re: [kernel-hardening] [RFC] module: add 'module_ronx=off' boot cmdline parameter to disable ro/nx module mappings

From: Kees Cook
Date: Tue Oct 18 2016 - 14:06:56 EST


On Tue, Oct 18, 2016 at 6:34 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> Hi,
>
> On Tue, Oct 18, 2016 at 03:09:51PM +0900, AKASHI Takahiro wrote:
>> As making CONFIG_DEBUG_RODATA mandatory is a good idea, so will be
>> for CONFIG_SET_MODULE_RONX.
>
> I completely agree, given most distros ship a large number of drivers as
> modules...
>
>> This patch adds a command line parameter, "module_ronx=," in order to
>> make this configuration always on in the future, but still allowing for
>> disabling read-only module mappings at boot time as "rodata=" does.
>>
>> I have, however, some concerns on this prototype:
>> (1) should we use a separate parameter like "module_ronx=," or
>> unify it with "rodata="?
>
> I think this should be merged with "rodata=".

Agreed: it's really just a development artifact that these configs are
separate to begin with, so I think we should continue to consolidate
and merge it with "rodata=".

-Kees

--
Kees Cook
Nexus Security