tree 2f7cfe5ecec2af776e9514340a4f3e4746ad185a
parent 3c117b543528b0d25801bd75444037dd0fcd2b8d
author Robin Murphy <robin.murphy@arm.com> 1478543109 +0000
committer Joerg Roedel <jroedel@suse.de> 1478613161 +0100

iommu/arm-smmu: Fix out-of-bounds dereference

When we iterate a master's config entries, what we generally care
about is the entry's stream map index, rather than the entry index
itself, so it's nice to have the iterator automatically assign the
former from the latter. Unfortunately, booting with KASAN reveals
the oversight that using a simple comma operator results in the
entry index being dereferenced before being checked for validity,
so we always access one element past the end of the fwspec array.

Flip things around so that the check always happens before the index
may be dereferenced.

Fixes: adfec2e709d2 ("iommu/arm-smmu: Convert to iommu_fwspec")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>