linux-kernel - [tip:x86/urgent] x86/entry/compat: Add missing CLAC to entry_INT80

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <tip-3d44d51bd339766f0178f0cf2e8d048b4a4872aa@git.kernel.org>
Date:	Wed, 24 Feb 2016 23:47:05 -0800
From:	tip-bot for Andy Lutomirski <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	luto@...nel.org, bp@...en8.de, luto@...capital.net,
	torvalds@...ux-foundation.org, brgerst@...il.com,
	tglx@...utronix.de, mingo@...nel.org, hpa@...or.com,
	dvlasenk@...hat.com, linux-kernel@...r.kernel.org,
	peterz@...radead.org
Subject: [tip:x86/urgent] x86/entry/compat: Add missing CLAC to
 entry_INT80_32

Commit-ID:  3d44d51bd339766f0178f0cf2e8d048b4a4872aa
Gitweb:     http://git.kernel.org/tip/3d44d51bd339766f0178f0cf2e8d048b4a4872aa
Author:     Andy Lutomirski <luto@...nel.org>
AuthorDate: Wed, 24 Feb 2016 12:18:49 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 25 Feb 2016 08:31:20 +0100

x86/entry/compat: Add missing CLAC to entry_INT80_32

This doesn't seem to fix a regression -- I don't think the CLAC was
ever there.

I double-checked in a debugger: entries through the int80 gate do
not automatically clear AC.

Stable maintainers: I can provide a backport to 4.3 and earlier if
needed.  This needs to be backported all the way to 3.10.

Reported-by: Brian Gerst <brgerst@...il.com>
Signed-off-by: Andy Lutomirski <luto@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: <stable@...r.kernel.org> # v3.10 and later
Fixes: 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user space access")
Link: http://lkml.kernel.org/r/b02b7e71ae54074be01fc171cbd4b72517055c0e.1456345086.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/entry/entry_64_compat.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index ff1c6d6..3c990ee 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -261,6 +261,7 @@ ENTRY(entry_INT80_compat)
 	 * Interrupts are off on entry.
 	 */
 	PARAVIRT_ADJUST_EXCEPTION_FRAME
+	ASM_CLAC			/* Do this early to minimize exposure */
 	SWAPGS
 
 	/*