[PATCH 3.12 053/103] drm/vmwgfx: Make sure user-space can't DMA across buffer object boundaries v2
From: Jiri Slaby <hidden>
Date: 2014-05-29 13:59:19
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lkml
Subsystem:
drm driver for vmware virtual gpu, drm drivers, drm drivers and misc gpu patches, the rest · Maintainers:
Zack Rusin, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds
From: Thomas Hellstrom <redacted> 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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 <redacted> Reviewed-by: Jakob Bornecrantz <redacted> Signed-off-by: Jiri Slaby <redacted> --- 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 8b059eb09d9b..1b9aa982257e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c@@ -834,14 +834,36 @@ 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);
--
1.9.3