drivers: hv: Turn off write permission on the hypercall page

BugLink: http://bugs.launchpad.net/bugs/1673118
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 9523f8836fc0ba95b4b99c040f9ed9726f673c63..2510dad631ba8fd0dbbff744ad2d296d0326c9c4 100644 (file)
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -228,7 +228,7 @@ 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;