Hi Robin,
On Mon, Jul 29, 2019 at 05:46:00PM +0100, Robin Murphy wrote:
> Since scatterlist dimensions are all unsigned ints, in the relatively
> rare cases where a device's max_segment_size is set to UINT_MAX, then
> the "cur_len + s_length <= max_len" check in __finalise_sg() will always
> return true. As a result, the corner case of such a device mapping an
> excessively large scatterlist which is mergeable to or beyond a total
> length of 4GB can lead to overflow and a bogus truncated dma_length in
> the resulting segment.
>
> As we already assume that any single segment must be no longer than
> max_len to begin with, this can easily be addressed by reshuffling the
> comparison.
Has this been triggered in the wild of can this patch wait for the next
merge window?
Regards,
Joerg
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