linux-kernel - Re: [PATCH v2] efi_64: Fix a missing-check bug in arch/x86/platform/efi/efi

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Message-ID: <CAKv+Gu-agMymoGm0G8Yj-siXwtPnqYjAHeu-wQwRT47Jqd27JA@mail.gmail.com>
Date:   Sat, 25 May 2019 11:18:36 +0200
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Gen Zhang <blackgod016574@...il.com>
Cc:     Darren Hart <dvhart@...radead.org>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] efi_64: Fix a missing-check bug in arch/x86/platform/efi/efi_64.c

On Sat, 25 May 2019 at 04:36, Gen Zhang <blackgod016574@...il.com> wrote:
>
> On Fri, May 24, 2019 at 06:07:10PM +0200, Ard Biesheuvel wrote:
> > Apologies for only spotting this now, but I seem to have given some bad advice.
> >
> > efi_call_phys_prolog() in efi_64.c will also return NULL if
> > (!efi_enabled(EFI_OLD_MEMMAP)), but this is not an error condition. So
> > that occurrence has to be updated: please return efi_mm.pgd instead.
> Thanks for your reply, Ard. You mean that we should return efi_mm.pgd
> when allcoation fails? And we should delete return EFI_ABORTED on the
> caller site, right? In that case, how should we handle the NULL pointer
> returned by condition if(!efi_enabled(EFI_OLD_MEMMAP)) on the caller
> site?
>

No, the other way around. I have already updated the patch, so don't
worry about it.

https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git/commit/?h=urgent&id=d2dc2bc7b60b936b95da4b04c2912c02974c3e9f