iommu/vt-d: Fix overflow of iommu->domains array

The valid range of 'did' in get_iommu_domain(*iommu, did)
is 0..cap_ndoms(iommu->cap), so don't exceed that
range in free_all_cpu_cached_iovas().

The user-visible impact of the out-of-bounds access is the machine
hanging on suspend-to-ram. It is, in fact, a kernel panic, but due
to already suspended devices, that's often not visible to the user.

Fixes: 22e2f9fa63b0 ("iommu/vt-d: Use per-cpu IOVA caching")
Signed-off-by: Jan Niehusmann <jan@gondor.com>
Tested-By: Marius Vlad <marius.c.vlad@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 10700945994eed2e470c92d267c0bb5723ed0d1a..cfe410eedaf0b9e7188ca462a4072443b3162bac 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4607,7 +4607,7 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
                if (!iommu)
                        continue;
 
-               for (did = 0; did < 0xffff; did++) {
+               for (did = 0; did < cap_ndoms(iommu->cap); did++) {
                        domain = get_iommu_domain(iommu, did);
 
                        if (!domain)