From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
It is possible that the scatter-gather table during dmabuf import has
non-zero offset of the data, but user-space doesn't expect that.
Fix this by failing the import, so user-space doesn't access wrong data.
Fixes: 37ccb44d0b00 ("xen/gntdev: Implement dma-buf import functionality")
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
---
drivers/xen/gntdev-dmabuf.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index 75d3bb948bf3..b1b6eebafd5d 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -613,6 +613,14 @@ dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
goto fail_detach;
}
+ /* Check that we have zero offset. */
+ if (sgt->sgl->offset) {
+ ret = ERR_PTR(-EINVAL);
+ pr_debug("DMA buffer has %d bytes offset, user-space expects 0\n",
+ sgt->sgl->offset);
+ goto fail_unmap;
+ }
+
/* Check number of pages that imported buffer has. */
if (attach->dmabuf->size != gntdev_dmabuf->nr_pages << PAGE_SHIFT) {
ret = ERR_PTR(-EINVAL);
--
2.17.1
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