From: Ian Forbes <ian.forbes@broadcom.com>
Date: Tue, 21 Oct 2025 19:01:28 +0000 (-0500)
Subject: drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE
X-Git-Tag: v6.18-rc6~14^2~2^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=32b415a9dc2c212e809b7ebc2b14bc3fbda2b9af;p=thirdparty%2Flinux.git

drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE

This data originates from userspace and is used in buffer offset
calculations which could potentially overflow causing an out-of-bounds
access.

Fixes: 8ce75f8ab904 ("drm/vmwgfx: Update device includes for DX device functionality")
Reported-by: Rohit Keshri <rkeshri@redhat.com>
Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Reviewed-by: Maaz Mombasawala <maaz.mombasawala@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patch.msgid.link/20251021190128.13014-1-ian.forbes@broadcom.com
---

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index d539f25b5fbe0..3057f8baa7d25 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -3668,6 +3668,11 @@ static int vmw_cmd_check(struct vmw_private *dev_priv,
 
 
 	cmd_id = header->id;
+	if (header->size > SVGA_CMD_MAX_DATASIZE) {
+		VMW_DEBUG_USER("SVGA3D command: %d is too big.\n",
+			       cmd_id + SVGA_3D_CMD_BASE);
+		return -E2BIG;
+	}
 	*size = header->size + sizeof(SVGA3dCmdHeader);
 
 	cmd_id -= SVGA_3D_CMD_BASE;