From cbd75e97a525e3819c02dc18bc2d67aa544c9e45 Mon Sep 17 00:00:00 2001
From: Thomas Hellstrom <thellstrom@vmware.com>
Date: Tue, 15 Apr 2014 18:25:48 +0200
Subject: [PATCH] drm/vmwgfx: Make sure user-space can't DMA across buffer
object boundaries v2
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.
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
---
drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 931490b9cfed0..87df0b3674fda 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -1214,14 +1214,36 @@ static int vmw_cmd_dma(struct vmw_private *dev_priv,
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);
--
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