[Patch Part3 V4 06/21] iommu/vt-d: Fix possible invalid memory access caused by free_dmar_iommu()

Jiang Liu
2014-07-11T06:17:15Z

Static identity and virtual machine domains may be cached in
iommu->domain_ids array after corresponding IOMMUs have been removed
from domain->iommu_bmp. So we should check domain->iommu_bmp before
decreasing domain->iommu_count in function free_dmar_iommu(), otherwise
it may cause free of inuse domain data structure.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 968e3d32e305..0984fa58d872 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -425,6 +425,8 @@ static void domain_remove_one_dev_info(struct dmar_domain *domain,
struct device *dev);
static void iommu_detach_dependent_devices(struct intel_iommu *iommu,
struct device *dev);
+static int domain_detach_iommu(struct dmar_domain *domain,
+ struct intel_iommu *iommu);

#ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
int dmar_disabled = 0;
@@ -1465,8 +1467,7 @@ static int iommu_init_domains(struct intel_iommu *iommu)
static void free_dmar_iommu(struct intel_iommu *iommu)
{
struct dmar_domain *domain;
- int i, count;
- unsigned long flags;
+ int i;

if ((iommu->domains) && (iommu->domain_ids)) {
for_each_set_bit(i, iommu->domain_ids, cap_ndoms(iommu->cap)) {
@@ -1479,11 +1480,7 @@ static void free_dmar_iommu(struct intel_iommu *iommu)

domain = iommu->domains[i];
clear_bit(i, iommu->domain_ids);
-
- spin_lock_irqsave(&domain->iommu_lock, flags);
- count = --domain->iommu_count;
- spin_unlock_irqrestore(&domain->iommu_lock, flags);
- if (count == 0)
+ if (domain_detach_iommu(domain, iommu) == 0)
domain_exit(domain);
}
}
--
1.7.10.4