Messages in this thread | | | Subject | Re: [PATCH 4/4] x86,module: Detect CRn and DRn manipulation | From | Jan Kiszka <> | Date | Wed, 8 Apr 2020 12:50:17 +0200 |
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On 08.04.20 11:13, Peter Zijlstra wrote: > On Wed, Apr 08, 2020 at 10:51:38AM +0200, Peter Zijlstra wrote: >> On Wed, Apr 08, 2020 at 07:58:53AM +0200, Jan Kiszka wrote: >>> On 07.04.20 23:48, Steven Rostedt wrote: >> >>>> Hmm, wont this break jailhouse? >> >> Breaking it isn't a problem, it's out of tree and it should be fixable. >> >>> Yes, possibly. We load the hypervisor binary via request_firmware into >>> executable memory and then jump into it. So most of the "suspicious" code is >> >> W.T.H. does the firmware loader have the ability to give executable >> memory? We need to kill that too. /me goes find. > > AFAICT the firmware loader only provides PAGE_KERNEL_RO, so how do you > get it executable?
memcpy(ioremapped_exec_region, firmware_image)
We only use the loader for getting the blob, not for running it. It has to be put at a location that Linux will lose control over anyway.
> > I'm thinking the patches Christoph has lined up will take care of this. >
It would make sense from a certain POV...
Jan
-- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux
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