Re: [PATCH] KVM: Prevent double-free on HPT resize commit path

From	Paul Mackerras <paulus@ozlabs.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] KVM: Prevent double-free on HPT resize commit path
Date	2017-02-28 13:10 +0100
Message-ID	<tfOLo-4dY-3@gated-at.bofh.it> (permalink)
References	<taYLo-2sg-7@gated-at.bofh.it> <tfEM2-5AN-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, Feb 28, 2017 at 11:56:55AM +1100, David Gibson wrote:
> On Wed, Feb 15, 2017 at 02:40:04PM +1100, David Gibson wrote:
> > resize_hpt_release(), called once the HPT resize of a KVM guest is
> > completed (successfully or unsuccessfully) free()s the state structure for
> > the resize.  It is currently not safe to call with a NULL pointer.
> > 
> > However, one of the error paths in kvm_vm_ioctl_resize_hpt_commit() can
> > invoke it with a NULL pointer.  This will occur if userspace improperly
> > invokes KVM_PPC_RESIZE_HPT_COMMIT without previously calling
> > KVM_PPC_RESIZE_HPT_PREPARE, or if it calls COMMIT twice without an
> > intervening PREPARE.
> > 
> > To fix this potential crash bug - and maybe others like it, make it safe
> > (and a no-op) to call resize_hpt_release() with a NULL resize pointer.
> > 
> > Found by Dan Carpenter with a static checker.
> > 
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> 
> Ping,
> 
> Paul have you taken this one?

Yes, thanks, it's in Linus' tree now.

Paul.

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[PATCH] KVM: Prevent double-free on HPT resize commit path David Gibson <david@gibson.dropbear.id.au> - 2017-02-15 04:50 +0100
  Re: [PATCH] KVM: Prevent double-free on HPT resize commit path David Gibson <david@gibson.dropbear.id.au> - 2017-02-28 02:30 +0100
    Re: [PATCH] KVM: Prevent double-free on HPT resize commit path Paul Mackerras <paulus@ozlabs.org> - 2017-02-28 13:10 +0100

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