Re: [PATCH 3/7] security: introduce kernel_fw_from_file hook

Luis R. Rodriguez
2014-07-22T22:40:43Z

On Tue, Jul 22, 2014 at 3:20 PM, Kees Cook <keescook@chromium.org> wrote:
> On Tue, Jul 22, 2014 at 3:11 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
>> On Tue, Jul 22, 2014 at 1:55 PM, Kees Cook <keescook@chromium.org> wrote:
>>> On Tue, Jul 22, 2014 at 12:39 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
>>>> On Mon, Jul 14, 2014 at 3:31 PM, Kees Cook <keescook@chromium.org> wrote:
>>>>> Yup, with this and the module hook, adding a similar hook for kexec
>>>>> makes sense as well. A paranoid kernel doesn't want to trust anything
>>>>> it's loading from userspace. :)
>>>>
>>>> Well I'm actually wondering if we could generalize requiring hooks or
>>>> not for LSM as part of the general kobject definition. Then we
>>>> wouldn't need to keep growing hooks for modules, firmware, kexec
>>>> images, etc, but instead using the interfaces for kobjects and who
>>>> depend on them. How that would actually look -- I'm not sure, but just
>>>> a thought.
>>>
>>> Yeah, there does seem to be a repeated "get a thing from userspace"
>>> method here, but the interfaces have been rather scattered so far. I
>>> haven't seen an obvious way to consolidate them yet.
>>
>> If we are going to be adding a new system call for each type of
>> userspace object to help LSMs with requirements I wonder if its a
>> worthy endeavor to review. This series didn't add one but you had
>> mentioned finit_module() for example, are we going to want one for
>> finit_firmware() finit_kexec_image(), etc?
>
> The kernel pulls in firmware directly from the filesystem, so no
> syscall there. :) kexec just had kexec_load_file added as a syscall
> (it takes 2 fds: kernel and initrd).

OK, too late then now. Look forward to the rest of the stuff then.

Luis