From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH -v2] x86, microcode, AMD: Sanity-check initrd image
Date: Mon, 03 Feb 2014 14:37:34 -0500 [thread overview]
Message-ID: <52EFEFFE.6010608@oracle.com> (raw)
In-Reply-To: <20140203193000.GD4281@pd.tnic>
On 02/03/2014 02:30 PM, Borislav Petkov wrote:
> On Mon, Feb 03, 2014 at 02:13:27PM -0500, Boris Ostrovsky wrote:
>> I thought that it may be sufficient to check for !container in
>> save_microcode_in_initrd_amd() before performing relocation. If the
>> signature was wrong, we would have found out about it in
>> load_ucode_bsp() -> apply_ucode_in_initrd() and returned right away,
> Your original test case which exploded had exactly that scenario - it
> was pointing to Intel ucode so container wasn't NULL. Thus we need to
> check the sig in find_ucode_in_initrd().
>
It exploded when 'if (!container)' check was done *after* relocation,
which made container non-zero. If you do the check *before* then I think
you will catch the fact that container is empty.
load_ucode_bsp() -> apply_ucode_in_initrd() path does not include
save_microcode_in_initrd_amd() and (if I understand the code correctly)
we already verify signature in apply_ucode_in_initrd().
I am pretty sure I tested this scenario but I can verify it again.
-boris
next prev parent reply other threads:[~2014-02-03 19:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <52DE94A9.9060505@oracle.com>
2014-01-21 16:14 ` AMD microcode loading broken on 32 bit Borislav Petkov
2014-01-21 17:55 ` Boris Ostrovsky
2014-01-21 18:25 ` Borislav Petkov
2014-01-23 18:08 ` Boris Ostrovsky
2014-01-23 18:54 ` Gene Heskett
2014-01-23 19:09 ` Boris Ostrovsky
2014-01-23 19:36 ` Gene Heskett
2014-01-23 19:29 ` Borislav Petkov
2014-01-23 19:41 ` Boris Ostrovsky
2014-01-28 16:24 ` Borislav Petkov
2014-01-28 20:43 ` Boris Ostrovsky
2014-01-28 20:52 ` Borislav Petkov
2014-01-28 21:05 ` Boris Ostrovsky
2014-01-28 21:30 ` Borislav Petkov
2014-01-28 21:37 ` Boris Ostrovsky
2014-01-28 23:10 ` Boris Ostrovsky
2014-01-28 23:22 ` Borislav Petkov
2014-01-30 15:13 ` Borislav Petkov
2014-01-30 19:41 ` Boris Ostrovsky
2014-01-30 19:54 ` Borislav Petkov
2014-02-03 17:55 ` [PATCH -v2] x86, microcode, AMD: Sanity-check initrd image Borislav Petkov
2014-02-03 19:13 ` Boris Ostrovsky
2014-02-03 19:30 ` Borislav Petkov
2014-02-03 19:37 ` Boris Ostrovsky [this message]
2014-02-03 19:52 ` Borislav Petkov
2014-02-03 20:28 ` Boris Ostrovsky
2014-02-03 20:33 ` Borislav Petkov
2014-02-03 20:41 ` [PATCH] x86, microcode, AMD: Unify valid container checks Borislav Petkov
2014-02-06 19:39 ` [tip:x86/urgent] " tip-bot for Borislav Petkov
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