From: Ard Biesheuvel <ardb@kernel.org>
To: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Ard Biesheuvel <ardb+git@google.com>,
"Kuppuswamy Sathyanarayanan,"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
linux-efi@vger.kernel.org
Subject: Re: [Bug Report] Bug in "efi/libstub: Add get_event_log() support for CC platforms"
Date: Thu, 7 Mar 2024 12:13:43 +0100 [thread overview]
Message-ID: <CAMj1kXGFLwsgPo9Xy_-9gaOUUO=wDd_K12ccYUhP1nWf3KLb0w@mail.gmail.com> (raw)
In-Reply-To: <CAMj1kXE166VdJLWSWo7_3MDw4V3zSuYRx44Z7yqyj5mQVOdDCA@mail.gmail.com>
On Thu, 7 Mar 2024 at 12:08, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> Hi Muhammad,
>
> Thanks for the report.
>
> On Thu, 7 Mar 2024 at 12:02, Muhammad Usama Anjum
> <usama.anjum@collabora.com> wrote:
> >
> > Hi,
> >
> > The recent patch:
> > 276805fb9c305: efi/libstub: Add get_event_log() support for CC platforms
> > has introduced
> > #define EFI_CC_EVENT_LOG_FORMAT_TCG_2 0x00000002
> >
> > But EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 has the same numerical value:
> > #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 0x2
> >
> > Thus there is dead code in efi_retrieve_tcg2_eventlog() i.e, multiple if
> > conditions with (version == 2) I'm unable to decide on what is wrong and
> > what is right here. Please have a look.
> >
>
> Why is this a problem? The compiler will recognize this and simplify
> the conditional. The code as written is semantically correct, the fact
> that the symbolic constants resolve to the same numerical value is
> just an implementation detail.
Ah hold on. I see what you mean now:
if (version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
final_events_table = get_efi_config_table(LINUX_EFI_TPM_FINAL_LOG_GUID);
+ else if (version == EFI_CC_EVENT_LOG_FORMAT_TCG_2)
+ final_events_table = get_efi_config_table(LINUX_EFI_CC_FINAL_LOG_GUID);
Yes, that is broken.
next prev parent reply other threads:[~2024-03-07 11:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-07 11:03 [Bug Report] Bug in "efi/libstub: Add get_event_log() support for CC platforms" Muhammad Usama Anjum
2024-03-07 11:08 ` Ard Biesheuvel
2024-03-07 11:13 ` Ard Biesheuvel [this message]
2024-03-07 11:30 ` Ard Biesheuvel
2024-03-07 15:36 ` Kuppuswamy Sathyanarayanan
2024-03-07 15:41 ` Ard Biesheuvel
2024-03-07 16:21 ` Kuppuswamy Sathyanarayanan
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