Re: [PATCH 5.15 0/6] arm64: kexec_file: use more system keyrings to verify kernel image signature + dependencies

["Michal Suchánek" <msuchanek@suse.de>]

On Fri, Sep 23, 2022 at 09:16:50PM +0200, Michal Suchánek wrote:
> Hello,
> 
> On Fri, Sep 23, 2022 at 03:03:36PM -0400, Mimi Zohar wrote:
> > On Fri, 2022-09-23 at 19:10 +0200, Michal Suchanek wrote:
> > > Hello,
> > > 
> > > this is backport of commit 0d519cadf751
> > > ("arm64: kexec_file: use more system keyrings to verify kernel image signature")
> > > to table 5.15 tree including the preparatory patches.
> > > 
> > > Some patches needed minor adjustment for context.
> > 
> > In general when backporting this patch set, there should be a
> > dependency on backporting these commits as well.  In this instance for
> > linux-5.15.y, they've already been backported.
> > 
> > 543ce63b664e ("lockdown: Fix kexec lockdown bypass with ima policy")

AFAICT this is everywhere relevant, likely because it's considered a CVE
fix.

> > af16df54b89d ("ima: force signature verification when CONFIG_KEXEC_SIG is configured")

This is missing in 5.4, and 5.4 is missing this prerequisite:
fd7af71be542 ("kexec: do not verify the signature without the lockdown or mandatory signature")

> 
> Thanks for bringing these up. It might be in general useful to backport
> these fixes as well.
> 
> However, this patchset does one very specific thing: it lifts the x86
> kexec_file signature verification to arch-independent and uses it on
> arm64 to unify all features (and any existing warts) between EFI
> architectures.
> 
> So unless I am missing something the fixes you pointed out are
> completely independent of this.
> 
> Thanks
> 
> Michal