dma-mapping: Add vmap checks to dma_map_single()

As we've seen from USB and other areas[1], we need to always do runtime
checks for DMA operating on memory regions that might be remapped. This
adds vmap checks (similar to those already in USB but missing in other
places) into dma_map_single() so all callers benefit from the checking.

[1] https://git.kernel.org/linus/9386c3e3fc54a4ef858215d12c36f391079e9bab

Suggested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
[hch: fixed the printk message]
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 10918c55003f7eba4a604568dade6697590d6cbe..4d450672b7d66826535ca4093f9dc332736c057c 100644 (file)
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -583,6 +583,10 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev)
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
                size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
+       /* DMA must never operate on areas that might be remapped. */
+       if (dev_WARN_ONCE(dev, is_vmalloc_addr(ptr),
+                         "rejecting DMA map of vmalloc memory\n"))
+               return DMA_MAPPING_ERROR;
        debug_dma_map_single(dev, ptr, size);
        return dma_map_page_attrs(dev, virt_to_page(ptr), offset_in_page(ptr),
                        size, dir, attrs);