Subject: Patch "[PATCH stable v4.14 04/32] powerpc: Use barrier_nospec in copy_from_user()" has been added to the 4.14-stable tree

From: <[email-masked]>
Date: Fri, 29 Mar 2019 15:54:48 +0100

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

    [PATCH stable v4.14 04/32] powerpc: Use barrier_nospec in copy_from_user()

to the 4.14-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:
     powerpc-use-barrier_nospec-in-copy_from_user.patch
and it can be found in the queue-4.14 subdirectory.

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

>From foo@baz Fri Mar 29 15:53:50 CET 2019
From: Michael Ellerman <[email-masked]>
Date: Fri, 29 Mar 2019 22:25:52 +1100
Subject: [PATCH stable v4.14 04/32] powerpc: Use barrier_nospec in copy_from_user()
To: [email-masked], [email-masked]
Cc: [email-masked], [email-masked], [email-masked], [email-masked]
Message-ID: <[email-masked]>

From: Michael Ellerman <[email-masked]>

commit ddf35cf3764b5a182b178105f57515b42e2634f8 upstream.

Based on the x86 commit doing the same.

See commit 304ec1b05031 ("x86/uaccess: Use __uaccess_begin_nospec()
and uaccess_try_nospec") and b3bbfb3fb5d2 ("x86: Introduce
__uaccess_begin_nospec() and uaccess_try_nospec") for more detail.

In all cases we are ordering the load from the potentially
user-controlled pointer vs a previous branch based on an access_ok()
check or similar.

Base on a patch from Michal Suchanek.

Signed-off-by: Michal Suchanek <[email-masked]>
Signed-off-by: Michael Ellerman <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>
---
 arch/powerpc/include/asm/uaccess.h |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -238,6 +238,7 @@ do {								\
 	__chk_user_ptr(ptr);					\
 	if (!is_kernel_addr((unsigned long)__gu_addr))		\
 		might_fault();					\
+	barrier_nospec();					\
 	__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
 	(x) = (__typeof__(*(ptr)))__gu_val;			\
 	__gu_err;						\
@@ -249,8 +250,10 @@ do {								\
 	__long_type(*(ptr)) __gu_val = 0;				\
 	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);		\
 	might_fault();							\
-	if (access_ok(VERIFY_READ, __gu_addr, (size)))			\
+	if (access_ok(VERIFY_READ, __gu_addr, (size))) {		\
+		barrier_nospec();					\
 		__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
+	}								\
 	(x) = (__force __typeof__(*(ptr)))__gu_val;				\
 	__gu_err;							\
 })
@@ -261,6 +264,7 @@ do {								\
 	__long_type(*(ptr)) __gu_val;				\
 	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
 	__chk_user_ptr(ptr);					\
+	barrier_nospec();					\
 	__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
 	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
 	__gu_err;						\
@@ -288,15 +292,19 @@ static inline unsigned long raw_copy_fro
 
 		switch (n) {
 		case 1:
+			barrier_nospec();
 			__get_user_size(*(u8 *)to, from, 1, ret);
 			break;
 		case 2:
+			barrier_nospec();
 			__get_user_size(*(u16 *)to, from, 2, ret);
 			break;
 		case 4:
+			barrier_nospec();
 			__get_user_size(*(u32 *)to, from, 4, ret);
 			break;
 		case 8:
+			barrier_nospec();
 			__get_user_size(*(u64 *)to, from, 8, ret);
 			break;
 		}
@@ -304,6 +312,7 @@ static inline unsigned long raw_copy_fro
 			return 0;
 	}
 
+	barrier_nospec();
 	return __copy_tofrom_user((__force void __user *)to, from, n);
 }

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

queue-4.14/powerpc-fsl-emulate-sprn_bucsr-register.patch
queue-4.14/powerpc-64-make-stf-barrier-ppc_book3s_64-specific.patch
queue-4.14/powerpc-fsl-fix-spectre_v2-mitigations-reporting.patch
queue-4.14/powerpc-64s-patch-barrier_nospec-in-modules.patch
queue-4.14/powerpc-pseries-query-hypervisor-for-count-cache-flush-settings.patch
queue-4.14/powerpc-64s-add-support-for-software-count-cache-flush.patch
queue-4.14/powerpc64s-show-ori31-availability-in-spectre_v1-sysfs-file-not-v2.patch
queue-4.14/powerpc-fsl-flush-the-branch-predictor-at-each-kernel-entry-64bit.patch
queue-4.14/powerpc-fsl-update-spectre-v2-reporting.patch
queue-4.14/powerpc-64-make-meltdown-reporting-book3s-64-specific.patch
queue-4.14/powerpc-64s-add-support-for-ori-barrier_nospec-patching.patch
queue-4.14/powerpc-use-barrier_nospec-in-copy_from_user.patch
queue-4.14/powerpc-fsl-sanitize-the-syscall-table-for-nxp-powerpc-32-bit-platforms.patch
queue-4.14/powerpc-fsl-add-macro-to-flush-the-branch-predictor.patch
queue-4.14/powerpc-fsl-add-barrier_nospec-implementation-for-nxp-powerpc-book3e.patch
queue-4.14/powerpc-security-fix-spectre_v2-reporting.patch
queue-4.14/powerpc-64-disable-the-speculation-barrier-from-the-command-line.patch
queue-4.14/powerpc-fsl-fix-the-flush-of-branch-predictor.patch
queue-4.14/powerpc-64-add-config_ppc_barrier_nospec.patch
queue-4.14/powerpc-fsl-enable-runtime-patching-if-nospectre_v2-boot-arg-is-used.patch
queue-4.14/powerpc-64-use-barrier_nospec-in-syscall-entry.patch
queue-4.14/powerpc-fsl-fixed-warning-orphan-section-__btb_flush_fixup.patch
queue-4.14/powerpc-fsl-add-nospectre_v2-command-line-argument.patch
queue-4.14/powerpc-64s-add-new-security-feature-flags-for-count-cache-flush.patch
queue-4.14/powerpc-fsl-add-infrastructure-to-fixup-branch-predictor-flush.patch
queue-4.14/powerpc-64s-enhance-the-information-in-cpu_show_spectre_v1.patch
queue-4.14/powerpc-64-call-setup_barrier_nospec-from-setup_arch.patch
queue-4.14/powerpc-asm-add-a-patch_site-macro-helpers-for-patching-instructions.patch
queue-4.14/powerpc-fsl-flush-the-branch-predictor-at-each-kernel-entry-32-bit.patch
queue-4.14/powerpc-64s-enable-barrier_nospec-based-on-firmware-settings.patch
queue-4.14/powerpc-fsl-flush-branch-predictor-when-entering-kvm.patch
queue-4.14/powerpc-powernv-query-firmware-for-count-cache-flush-settings.patch