[PATCH 4.14 140/183] powerpc/powernv: Make opal log only readable by root

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jordan Niethe <jniethe5@xxxxxxxxx>

commit 7b62f9bd2246b7d3d086e571397c14ba52645ef1 upstream.

Currently the opal log is globally readable. It is kernel policy to
limit the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it
would be better to limit the readability to root.

Fixes: bfc36894a48b ("powerpc/powernv: Add OPAL message log interface")
Cc: stable@xxxxxxxxxxxxxxx # v3.15+
Signed-off-by: Jordan Niethe <jniethe5@xxxxxxxxx>
Reviewed-by: Stewart Smith <stewart@xxxxxxxxxxxxx>
Reviewed-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/platforms/powernv/opal-msglog.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/opal-msglog.c
+++ b/arch/powerpc/platforms/powernv/opal-msglog.c
@@ -98,7 +98,7 @@ static ssize_t opal_msglog_read(struct f
 }
 
 static struct bin_attribute opal_msglog_attr = {
-	.attr = {.name = "msglog", .mode = 0444},
+	.attr = {.name = "msglog", .mode = 0400},
 	.read = opal_msglog_read
 };