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Patch "x86/asm/64: Clear AC on NMI entries" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message Aug 20, 2017

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This is a note to let you know that I've just added the patch titled

x86/asm/64: Clear AC on NMI entries

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     x86-asm-64-clear-ac-on-nmi-entries.patch

and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From e93c17301ac55321fc18e0f8316e924e58a83c8c Mon Sep 17 00:00:00 2001

From: Andy Lutomirski <[email protected]>
Date: Mon, 7 Aug 2017 19:43:13 -0700
Subject: x86/asm/64: Clear AC on NMI entries

From: Andy Lutomirski <[email protected]>

commit e93c17301ac55321fc18e0f8316e924e58a83c8c upstream.

This closes a hole in our SMAP implementation.

This patch comes from grsecurity. Good catch!

---
 arch/x86/entry/entry_64.S |    2 ++
 1 file changed, 2 insertions(+)
arch/x86/entry/entry_64.S +2 -0
@@ -1190,6 +1190,8 @@ ENTRY(nmi)
 	 * other IST entries.
 	 */
 
+	ASM_CLAC
+
 	/* Use %rdx as our temp variable throughout */
 	pushq	%rdx
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/x86-asm-64-clear-ac-on-nmi-entries.patch