powerpc/powernv: Make opal log only readable by root

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@vger.kernel.org # v3.15+
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Stewart Smith <stewart@linux.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/platforms/powernv/opal-msglog.c b/arch/powerpc/platforms/powernv/opal-msglog.c
index acd3206..06628c7 100644 (file)
--- 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 file *file, struct kobject *kobj,
 }
 
 static struct bin_attribute opal_msglog_attr = {
-       .attr = {.name = "msglog", .mode = 0444},
+       .attr = {.name = "msglog", .mode = 0400},
        .read = opal_msglog_read
 };