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dma-buf: fix integer overflow in fill_sg_entry() for buffers >= 8GiB

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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: 3aa31a8bb1 ("dma-buf: provide phys_vec to scatter-gather mapping routine")
Signed-off-by: Alex Mastro <amastro@fb.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Leon Romanovsky <leon@kernel.org>
Link: https://lore.kernel.org/r/20251125-dma-buf-overflow-v1-1-b70ea1e6c4ba@fb.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
This commit is contained in:
Alex Mastro
2025-11-25 17:11:18 -08:00
committed by Alex Williamson
parent 98693e0897
commit 590d745680
1 changed files with 1 additions and 1 deletions
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2
drivers/dma-buf/dma-buf-mapping.c
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@@ -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);
}