From 590d745680309f8d956c3f0a97270fe65013b272 Mon Sep 17 00:00:00 2001 From: Alex Mastro Date: Tue, 25 Nov 2025 17:11:18 -0800 Subject: [PATCH] dma-buf: fix integer overflow in fill_sg_entry() for buffers >= 8GiB fill_sg_entry() splits large DMA buffers into multiple scatter-gather entries, each holding up to UINT_MAX bytes. When calculating the DMA address for entries beyond the second one, the expression (i * UINT_MAX) causes integer overflow due to 32-bit arithmetic. This manifests when the input arg length >= 8 GiB results in looping for i >= 2. Fix by casting i to dma_addr_t before multiplication. Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping routine") Signed-off-by: Alex Mastro Reviewed-by: Jason Gunthorpe Reviewed-by: Leon Romanovsky Link: https://lore.kernel.org/r/20251125-dma-buf-overflow-v1-1-b70ea1e6c4ba@fb.com Signed-off-by: Alex Williamson --- drivers/dma-buf/dma-buf-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-mapping.c index b4819811a64a0..b7352e609fbdf 100644 --- a/drivers/dma-buf/dma-buf-mapping.c +++ b/drivers/dma-buf/dma-buf-mapping.c @@ -24,7 +24,7 @@ static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, * does not require the CPU list for mapping or unmapping. */ sg_set_page(sgl, NULL, 0, 0); - sg_dma_address(sgl) = addr + i * UINT_MAX; + sg_dma_address(sgl) = addr + (dma_addr_t)i * UINT_MAX; sg_dma_len(sgl) = len; sgl = sg_next(sgl); } -- 2.47.3