parisc: fix copy_from_user()

[ Upstream commit aace880feea38875fbc919761b77e5732a3659ef ]

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index df9d8dd72db296ae2ec4d147f3e89d39f10e6926..3c38f8535499344547006a3d20c89dd0b40c3f4c 100644 (file)
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -10,6 +10,7 @@
 #include <asm-generic/uaccess-unaligned.h>
 
 #include <linux/bug.h>
+#include <linux/string.h>
 
 #define VERIFY_READ 0
 #define VERIFY_WRITE 1
@@ -245,13 +246,14 @@ static inline unsigned long __must_check copy_from_user(void *to,
                                           unsigned long n)
 {
         int sz = __compiletime_object_size(to);
-        int ret = -EFAULT;
+        unsigned long ret = n;
 
         if (likely(sz == -1 || !__builtin_constant_p(n) || sz >= n))
                 ret = __copy_from_user(to, from, n);
         else
                 copy_from_user_overflow();
-
+       if (unlikely(ret))
+               memset(to + (n - ret), 0, ret);
         return ret;
 }