On Wed, 26 Nov 2025 14:01:07 -0400
Jason Gunthorpe <[email protected]> wrote:
> On Tue, Nov 25, 2025 at 05:11:18PM -0800, Alex Mastro wrote:
> > 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 <[email protected]>
> > ---
> > More color about how I discovered this in [1] for the commit at [2]:
> >
> > [1] https://lore.kernel.org/all/[email protected]
> > [2]
> > https://lore.kernel.org/all/[email protected]
> > ---
> > drivers/dma-buf/dma-buf-mapping.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Reviewed-by: Jason Gunthorpe <[email protected]>
>
> AlexW, can you pick this up?
Yes, I'm planning to. Thanks,
Alex
