linux-kernel - [PATCH 3.12 60/60] drivers: hv: Turn off write permission on the hypercall page

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Message-Id: <8722bc8f8d7f1ca60b4d8515d717cd780f5d1685.1489497268.git.jslaby@suse.cz>
Date:   Tue, 14 Mar 2017 14:15:51 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        "K. Y. Srinivasan" <kys@...rosoft.com>, Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 60/60] drivers: hv: Turn off write permission on the hypercall page

From: "K. Y. Srinivasan" <kys@...rosoft.com>

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

===============

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@...rosoft.com>
Acked-by: Kees Cook <keescook@...omium.org>
Reported-by: Stephen Hemminger <stephen@...workplumber.org>
Tested-by: Stephen Hemminger <stephen@...workplumber.org>
Signed-off-by: Jiri Slaby <jslaby@...e.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 3fdb9af08705..9c0d458ec232 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;
-- 
2.12.0