From 4cf949c7fafe21e085a4ee386bb2dade9067316e Mon Sep 17 00:00:00 2001

From: Zack Rusin <zackr@vmware.com>

Date: Tue, 25 Oct 2022 23:19:35 -0400

Subject: drm/vmwgfx: Validate the box size for the snooped cursor

Git-commit: 4cf949c7fafe21e085a4ee386bb2dade9067316e

Patch-mainline: v6.2-rc1

References: bsc#1203332 CVE-2022-36280

Invalid userspace dma surface copies could potentially overflow

the memcpy from the surface to the snooped image leading to crashes.

To fix it the dimensions of the copybox have to be validated

against the expected size of the snooped cursor.

Signed-off-by: Zack Rusin <zackr@vmware.com>

Fixes: 2ac863719e51 ("vmwgfx: Snoop DMA transfers with non-covering sizes")

Cc: <stable@vger.kernel.org> # v3.2+

Reviewed-by: Michael Banack <banackm@vmware.com>

Reviewed-by: Martin Krastev <krastevm@vmware.com>

Link: https://patchwork.freedesktop.org/patch/msgid/20221026031936.1004280-1-zack@kde.org

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

---

 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

index 0342efdf9063..d434b6ae1092 100644

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -393,7 +393,8 @@ void vmw_kms_cursor_snoop(struct vmw_surface *srf,

 	if (cmd->dma.guest.ptr.offset % PAGE_SIZE ||

 	    box->x != 0    || box->y != 0    || box->z != 0    ||

 	    box->srcx != 0 || box->srcy != 0 || box->srcz != 0 ||

-	    box->d != 1    || box_count != 1) {

+	    box->d != 1    || box_count != 1 ||

+	    box->w > 64 || box->h > 64) {

 		/* TODO handle none page aligned offsets */

 		/* TODO handle more dst & src != 0 */

 		/* TODO handle more then one copy */

-- 

2.39.1