From 8722bc8f8d7f1ca60b4d8515d717cd780f5d1685 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: Wed, 8 Feb 2017 18:30:56 -0700
Subject: [PATCH] drivers: hv: Turn off write permission on the hypercall page

commit 372b1e91343e657a7cc5e2e2bcecd5140ac28119 upstream.

The hypercall page only needs to be executable but currently it is setup to
be writable as well. Fix the issue.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Tested-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/hv/hv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 3fdb9af087054..9c0d458ec2329 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -154,7 +154,7 @@ int hv_init(void)
 	/* See if the hypercall page is already set */
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 
-	virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
+	virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
 
 	if (!virtaddr)
 		goto cleanup;