Groups > linux.debian.bugs.dist > #1148023

Bug#1036543: [PATCH 5.10 076/529] crypto: ccp: Use the stack for small SEV command buffers

From	Ben Hutchings <ben@decadent.org.uk>
Newsgroups	linux.debian.bugs.dist, linux.debian.kernel
Subject	Bug#1036543: [PATCH 5.10 076/529] crypto: ccp: Use the stack for small SEV command buffers
Date	2023-05-26 17:40 +0200
Message-ID	<GzHHP-bAx7-5@gated-at.bofh.it> (permalink)
References	(2 earlier) <GzHHP-bAx7-11@gated-at.bofh.it> <GzHHP-bAx7-13@gated-at.bofh.it> <GzHHP-bAx7-15@gated-at.bofh.it> <Gy9yy-aDdA-7@gated-at.bofh.it> <GzHHP-bAx7-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Cross-posted to 2 groups.

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On Wed, 2023-05-17 at 16:06 +0200, Greg Kroah-Hartman wrote:
> On Wed, May 17, 2023 at 04:02:35PM +0200, Greg Kroah-Hartman wrote:
> > On Wed, May 17, 2023 at 02:56:21PM +0200, Ben Hutchings wrote:
> > > On Fri, 2023-03-10 at 14:33 +0100, Greg Kroah-Hartman wrote:
> > > > From: Sean Christopherson <seanjc@google.com>
> > > > 
> > > > [ Upstream commit e4a9af799e5539b0feb99571f0aaed5a3c81dc5a ]
> > > > 
> > > > For commands with small input/output buffers, use the local stack to
> > > > "allocate" the structures used to communicate with the PSP.   Now that
> > > > __sev_do_cmd_locked() gracefully handles vmalloc'd buffers, there's no
> > > > reason to avoid using the stack, e.g. CONFIG_VMAP_STACK=y will just work.
> > > [...]
> > > 
> > > Julien Cristau reported a regression in ccp - the
> > > WARN_ON_ONCE(!virt_addr_valid(data)) is now being triggered.  I believe
> > > this was introduced by the above commit, which depends on:
> > > 
> > > commit 8347b99473a313be6549a5b940bc3c56a71be81c
> > > Author: Sean Christopherson <seanjc@google.com>
> > > Date:   Tue Apr 6 15:49:48 2021 -0700
> > >  
> > >     crypto: ccp: Play nice with vmalloc'd memory for SEV command structs
> > > 
> > > Ben.
> > > 
> > 
> > Thanks for letting me know, now queued up.
> 
> Nope, now dropped, it breaks the build :(

I've now looked further and found that we need both:

d5760dee127b crypto: ccp: Reject SEV commands with mismatching command buffer
8347b99473a3 crypto: ccp: Play nice with vmalloc'd memory for SEV command structs

(Not yet tested; I'll ask Julien if he can do that.)

Ben.

-- 
Ben Hutchings
I haven't lost my mind; it's backed up on tape somewhere.

Thread

Bug#1036543: linux: WARNING at drivers/crypto/ccp/sev-dev.c:168 __sev_do_cmd_locked+0x31b/0x350 [ccp] Julien Cristau <jcristau@debian.org> - 2023-05-22 11:00 +0200
  Bug#1036543: [PATCH 5.10 076/529] crypto: ccp: Use the stack for small SEV command buffers Ben Hutchings <ben@decadent.org.uk> - 2023-05-26 17:40 +0200
    Bug#1036543: [PATCH 5.10 076/529] crypto: ccp: Use the stack for small SEV command buffers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2023-06-07 20:10 +0200

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