linux-kernel - [PATCH 2/8] virt: vbox: Fix guest capabilities mask check

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Message-Id: <20200520195440.38759-2-hdegoede@redhat.com>
Date:   Wed, 20 May 2020 21:54:34 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Hans de Goede <hdegoede@...hat.com>, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: [PATCH 2/8] virt: vbox: Fix guest capabilities mask check

Check the passed in capabilities against VMMDEV_GUEST_CAPABILITIES_MASK
instead of against VMMDEV_EVENT_VALID_EVENT_MASK.
This tightens the allowed mask from 0x7ff to 0x7.

Fixes: 0ba002bc4393 ("virt: Add vboxguest driver for Virtual Box Guest integration")
Cc: stable@...r.kernel.org
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
---
 drivers/virt/vboxguest/vboxguest_core.c | 2 +-
 drivers/virt/vboxguest/vmmdev.h         | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/virt/vboxguest/vboxguest_core.c b/drivers/virt/vboxguest/vboxguest_core.c
index 8fab04e76c14..18ebd7a6af98 100644
--- a/drivers/virt/vboxguest/vboxguest_core.c
+++ b/drivers/virt/vboxguest/vboxguest_core.c
@@ -1444,7 +1444,7 @@ static int vbg_ioctl_change_guest_capabilities(struct vbg_dev *gdev,
 	or_mask = caps->u.in.or_mask;
 	not_mask = caps->u.in.not_mask;
 
-	if ((or_mask | not_mask) & ~VMMDEV_EVENT_VALID_EVENT_MASK)
+	if ((or_mask | not_mask) & ~VMMDEV_GUEST_CAPABILITIES_MASK)
 		return -EINVAL;
 
 	ret = vbg_set_session_capabilities(gdev, session, or_mask, not_mask,
diff --git a/drivers/virt/vboxguest/vmmdev.h b/drivers/virt/vboxguest/vmmdev.h
index 6337b8d75d96..21f408120e3f 100644
--- a/drivers/virt/vboxguest/vmmdev.h
+++ b/drivers/virt/vboxguest/vmmdev.h
@@ -206,6 +206,8 @@ VMMDEV_ASSERT_SIZE(vmmdev_mask, 24 + 8);
  * not.
  */
 #define VMMDEV_GUEST_SUPPORTS_GRAPHICS                      BIT(2)
+/* The mask of valid capabilities, for sanity checking. */
+#define VMMDEV_GUEST_CAPABILITIES_MASK                      0x00000007U
 
 /** struct vmmdev_hypervisorinfo - Hypervisor info structure. */
 struct vmmdev_hypervisorinfo {
-- 
2.26.2