[PATCH 3.10 172/268] drivers: hv: Turn off write permission on the hypercall page

Willy Tarreau
2017-06-19T19:07:44Z

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

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>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
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 b103955..4e4cb3d 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;
--
2.8.0.rc2.1.gbe9624a