Robin Murphy ab2cbeb0ed iommu/dma: Handle SG length overflow better
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.

Fixes: 809eac54cdd6 ("iommu/dma: Implement scatterlist segment merging")
Reported-by: Nicolin Chen <nicoleotsuka@gmail.com>
Tested-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
2019-08-09 17:31:39 +02:00
..
2019-07-22 17:50:49 +02:00
2019-06-06 17:32:13 -04:00
2019-06-06 17:32:13 -04:00