[PATCH AUTOSEL 5.6 107/129] iommu/virtio: Fix freeing of incomplete domains

Sasha Levin
2020-04-15T12:57:49Z

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

[ Upstream commit 7062af3ed2ba451029e3733d9f677c68f5ea9e77 ]

Calling viommu_domain_free() on a domain that hasn't been finalised (not
attached to any device, for example) can currently cause an Oops,
because we attempt to call ida_free() on ID 0, which may either be
unallocated or used by another domain.

Only initialise the vdomain->viommu pointer, which denotes a finalised
domain, at the end of a successful viommu_domain_finalise().

Fixes: edcd69ab9a32 ("iommu: Add virtio-iommu driver")
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20200326093558.2641019-3-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/virtio-iommu.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index cce329d71fbad..5eed75cd121f1 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -613,18 +613,20 @@ static int viommu_domain_finalise(struct viommu_dev *viommu,
int ret;
struct viommu_domain *vdomain = to_viommu_domain(domain);

- vdomain->viommu = viommu;
- vdomain->map_flags = viommu->map_flags;
+ ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain,
+ viommu->last_domain, GFP_KERNEL);
+ if (ret < 0)
+ return ret;
+
+ vdomain->id = (unsigned int)ret;

domain->pgsize_bitmap = viommu->pgsize_bitmap;
domain->geometry = viommu->geometry;

- ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain,
- viommu->last_domain, GFP_KERNEL);
- if (ret >= 0)
- vdomain->id = (unsigned int)ret;
+ vdomain->map_flags = viommu->map_flags;
+ vdomain->viommu = viommu;

- return ret > 0 ? 0 : ret;
+ return 0;
}

static void viommu_domain_free(struct iommu_domain *domain)
--
2.20.1