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Date: Thu, 13 Dec 2018 20:13:15 +0100
From: <gregkh@...uxfoundation.org>
To: 151727416438.33451.17309465232057176966.stgit@...llia2-desk3.amr.corp.intel.com,alan@...ux.intel.com,ben.hutchings@...ethink.co.uk,dan.j.williams@...el.com,gregkh@...uxfoundation.org,keescook@...omium.org,kernel-hardening@...ts.openwall.com,mingo@...hat.com,tglx@...utronix.de,thomas.lendacky@....com,torvalds@...ux-foundation.org,viro@...iv.linux.org.uk
Cc: <stable-commits@...r.kernel.org>
Subject: Patch "x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end}" has been added to the 4.4-stable tree


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

    x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end}

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-usercopy-replace-open-coded-stac-clac-with-__uaccess_-begin-end.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 <stable@...r.kernel.org> know about it.


>From foo@baz Thu Dec 13 20:11:30 CET 2018
From: Dan Williams <dan.j.williams@...el.com>
Date: Mon, 29 Jan 2018 17:02:44 -0800
Subject: x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end}

From: Dan Williams <dan.j.williams@...el.com>

commit b5c4ae4f35325d520b230bab6eb3310613b72ac1 upstream.

In preparation for converting some __uaccess_begin() instances to
__uacess_begin_nospec(), make sure all 'from user' uaccess paths are
using the _begin(), _end() helpers rather than open-coded stac() and
clac().

No functional changes.

Suggested-by: Ingo Molnar <mingo@...hat.com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-arch@...r.kernel.org
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Kees Cook <keescook@...omium.org>
Cc: kernel-hardening@...ts.openwall.com
Cc: gregkh@...uxfoundation.org
Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: torvalds@...ux-foundation.org
Cc: alan@...ux.intel.com
Link: https://lkml.kernel.org/r/151727416438.33451.17309465232057176966.stgit@dwillia2-desk3.amr.corp.intel.com
[bwh: Backported to 4.4:
 - Convert several more functions to use __uaccess_begin_nospec(), that
   are just wrappers in mainline
 - Adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@...ethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/lib/usercopy_32.c |   20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -570,12 +570,12 @@ do {									\
 unsigned long __copy_to_user_ll(void __user *to, const void *from,
 				unsigned long n)
 {
-	stac();
+	__uaccess_begin();
 	if (movsl_is_ok(to, from, n))
 		__copy_user(to, from, n);
 	else
 		n = __copy_user_intel(to, from, n);
-	clac();
+	__uaccess_end();
 	return n;
 }
 EXPORT_SYMBOL(__copy_to_user_ll);
@@ -583,12 +583,12 @@ EXPORT_SYMBOL(__copy_to_user_ll);
 unsigned long __copy_from_user_ll(void *to, const void __user *from,
 					unsigned long n)
 {
-	stac();
+	__uaccess_begin();
 	if (movsl_is_ok(to, from, n))
 		__copy_user_zeroing(to, from, n);
 	else
 		n = __copy_user_zeroing_intel(to, from, n);
-	clac();
+	__uaccess_end();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll);
@@ -596,13 +596,13 @@ EXPORT_SYMBOL(__copy_from_user_ll);
 unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from,
 					 unsigned long n)
 {
-	stac();
+	__uaccess_begin();
 	if (movsl_is_ok(to, from, n))
 		__copy_user(to, from, n);
 	else
 		n = __copy_user_intel((void __user *)to,
 				      (const void *)from, n);
-	clac();
+	__uaccess_end();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll_nozero);
@@ -610,7 +610,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nozero
 unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from,
 					unsigned long n)
 {
-	stac();
+	__uaccess_begin();
 #ifdef CONFIG_X86_INTEL_USERCOPY
 	if (n > 64 && cpu_has_xmm2)
 		n = __copy_user_zeroing_intel_nocache(to, from, n);
@@ -619,7 +619,7 @@ unsigned long __copy_from_user_ll_nocach
 #else
 	__copy_user_zeroing(to, from, n);
 #endif
-	clac();
+	__uaccess_end();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll_nocache);
@@ -627,7 +627,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocach
 unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
 					unsigned long n)
 {
-	stac();
+	__uaccess_begin();
 #ifdef CONFIG_X86_INTEL_USERCOPY
 	if (n > 64 && cpu_has_xmm2)
 		n = __copy_user_intel_nocache(to, from, n);
@@ -636,7 +636,7 @@ unsigned long __copy_from_user_ll_nocach
 #else
 	__copy_user(to, from, n);
 #endif
-	clac();
+	__uaccess_end();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);


Patches currently in stable-queue which might be from dan.j.williams@...el.com are

queue-4.4/x86-introduce-__uaccess_begin_nospec-and-uaccess_try_nospec.patch
queue-4.4/kvm-vmx-emulate-msr_ia32_arch_capabilities.patch
queue-4.4/x86-usercopy-replace-open-coded-stac-clac-with-__uaccess_-begin-end.patch
queue-4.4/x86-uaccess-use-__uaccess_begin_nospec-and-uaccess_try_nospec.patch
queue-4.4/kvm-vmx-allow-direct-access-to-msr_ia32_spec_ctrl.patch
queue-4.4/kvm-x86-add-ibpb-support.patch
queue-4.4/kvm-svm-allow-direct-access-to-msr_ia32_spec_ctrl.patch

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