linux-kernel - Re: [PATCH 1/2] x86, amd-ucode: Check UCODE_MAGIC before loading the container file

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Date:	Sun, 8 Nov 2009 15:10:17 +0100
From:	Borislav Petkov <petkovbb@...glemail.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Andreas Herrmann <herrmann.der.user@...glemail.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
	Borislav Petkov <borislav.petkov@....com>
Subject: Re: [PATCH 1/2] x86, amd-ucode: Check UCODE_MAGIC before loading
 the container file

Hi Ingo,

On Sun, Nov 08, 2009 at 01:04:18PM +0100, Ingo Molnar wrote:
> hm, there's no changelog. How was it found,

code staring :)

> what's the significance,

required by design.

> do we want it for .32 - i suspect we want - but we need a better
> changelog for that.

Yes. How's that?

--
>From f41bced57e05c8adc0d2c13864b6323c191d45d2 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <borislav.petkov@....com>
Date: Thu, 29 Oct 2009 14:00:54 +0100
Subject: [PATCH] x86, amd-ucode: Check UCODE_MAGIC before loading the container file

When loading a microcode binary, we should check the microcode magic
value embedded in the image before continuing loading. The original
check got lost somehow so re-add it to the firmware requesting path.

Signed-off-by: Borislav Petkov <borislav.petkov@....com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@....com>
---
 arch/x86/kernel/microcode_amd.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c
index 366baa1..f4c538b 100644
--- a/arch/x86/kernel/microcode_amd.c
+++ b/arch/x86/kernel/microcode_amd.c
@@ -317,6 +317,12 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device)
 		return UCODE_NFOUND;
 	}
 
+	if (*(u32 *)firmware->data != UCODE_MAGIC) {
+		printk(KERN_ERR "microcode: invalid UCODE_MAGIC (0x%08x)\n",
+		       *(u32 *)firmware->data);
+		return UCODE_ERROR;
+	}
+
 	ret = generic_load_microcode(cpu, firmware->data, firmware->size);
 
 	release_firmware(firmware);
-- 
1.6.5


-- 
Regards/Gruss,
    Boris.
--
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