drm/vmwgfx: Make sure user-space can't DMA across buffer object boundaries v2
commit cbd75e97a525e3819c02dc18bc2d67aa544c9e45 upstream.
We already check that the buffer object we're accessing is registered with
the file. Now also make sure that we can't DMA across buffer object boundaries.
v2: Code commenting update.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 394e647..da068bd 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -834,14 +834,36 @@
SVGA3dCmdSurfaceDMA dma;
} *cmd;
int ret;
+ SVGA3dCmdSurfaceDMASuffix *suffix;
+ uint32_t bo_size;
cmd = container_of(header, struct vmw_dma_cmd, header);
+ suffix = (SVGA3dCmdSurfaceDMASuffix *)((unsigned long) &cmd->dma +
+ header->size - sizeof(*suffix));
+
+ /* Make sure device and verifier stays in sync. */
+ if (unlikely(suffix->suffixSize != sizeof(*suffix))) {
+ DRM_ERROR("Invalid DMA suffix size.\n");
+ return -EINVAL;
+ }
+
ret = vmw_translate_guest_ptr(dev_priv, sw_context,
&cmd->dma.guest.ptr,
&vmw_bo);
if (unlikely(ret != 0))
return ret;
+ /* Make sure DMA doesn't cross BO boundaries. */
+ bo_size = vmw_bo->base.num_pages * PAGE_SIZE;
+ if (unlikely(cmd->dma.guest.ptr.offset > bo_size)) {
+ DRM_ERROR("Invalid DMA offset.\n");
+ return -EINVAL;
+ }
+
+ bo_size -= cmd->dma.guest.ptr.offset;
+ if (unlikely(suffix->maximumOffset > bo_size))
+ suffix->maximumOffset = bo_size;
+
ret = vmw_cmd_res_check(dev_priv, sw_context, vmw_res_surface,
user_surface_converter, &cmd->dma.host.sid,
NULL);