linux-kernel - [PATCH 4.14 27/45] powerpc: Add barrier_nospec to raw_copy_in

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Date:   Wed, 18 Sep 2019 08:19:05 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Suraj Jitindar Singh <sjitindarsingh@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.14 27/45] powerpc: Add barrier_nospec to raw_copy_in_user()

From: Suraj Jitindar Singh <sjitindarsingh@...il.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@...il.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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
@@ -280,6 +280,7 @@ extern unsigned long __copy_tofrom_user(
 static inline unsigned long
 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 {
+	barrier_nospec();
 	return __copy_tofrom_user(to, from, n);
 }
 #endif /* __powerpc64__ */