[PATCH 5.2 49/85] powerpc: Add barrier_nospec to raw_copy_in_user()

Greg Kroah-Hartman
2019-09-18T06:26:11Z

From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>

commit 6fbcdd59094ade30db63f32316e9502425d7b256 upstream.

Commit ddf35cf3764b ("powerpc: Use barrier_nospec in copy_from_user()")
Added barrier_nospec before loading from user-controlled pointers. The
intention was to order the load from the potentially user-controlled
pointer vs a previous branch based on an access_ok() check or similar.

In order to achieve the same result, add a barrier_nospec to the
raw_copy_in_user() function before loading from such a user-controlled
pointer.

Fixes: ddf35cf3764b ("powerpc: Use barrier_nospec in copy_from_user()")
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/include/asm/uaccess.h | 1 +
1 file changed, 1 insertion(+)

--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -312,6 +312,7 @@ raw_copy_in_user(void __user *to, const
{
unsigned long ret;

+ barrier_nospec();
allow_user_access(to, from, n);
ret = __copy_tofrom_user(to, from, n);
prevent_user_access(to, from, n);