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authorJean-Philippe Brucker2022-04-26 14:04:45 +0100
committerWill Deacon2022-05-06 16:25:39 +0100
commitcbd23144f7662b00bcde32a938c4a4057e476d68 (patch)
tree258cc5bf56bc772f6db3fef3915dbc3820f1bdf3 /drivers/iommu
parentb131fa8c1d2afd05d0b7598621114674289c2fbb (diff)
iommu/arm-smmu-v3-sva: Fix mm use-after-free
We currently call arm64_mm_context_put() without holding a reference to the mm, which can result in use-after-free. Call mmgrab()/mmdrop() to ensure the mm only gets freed after we unpinned the ASID. Fixes: 32784a9562fb ("iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()") Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> Link: https://lore.kernel.org/r/20220426130444.300556-1-jean-philippe@linaro.org Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index c623dae1e115..1ef7bbb4acf3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -6,6 +6,7 @@
#include <linux/mm.h>
#include <linux/mmu_context.h>
#include <linux/mmu_notifier.h>
+#include <linux/sched/mm.h>
#include <linux/slab.h>
#include "arm-smmu-v3.h"
@@ -96,9 +97,14 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
struct arm_smmu_ctx_desc *cd;
struct arm_smmu_ctx_desc *ret = NULL;
+ /* Don't free the mm until we release the ASID */
+ mmgrab(mm);
+
asid = arm64_mm_context_get(mm);
- if (!asid)
- return ERR_PTR(-ESRCH);
+ if (!asid) {
+ err = -ESRCH;
+ goto out_drop_mm;
+ }
cd = kzalloc(sizeof(*cd), GFP_KERNEL);
if (!cd) {
@@ -165,6 +171,8 @@ out_free_cd:
kfree(cd);
out_put_context:
arm64_mm_context_put(mm);
+out_drop_mm:
+ mmdrop(mm);
return err < 0 ? ERR_PTR(err) : ret;
}
@@ -173,6 +181,7 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
if (arm_smmu_free_asid(cd)) {
/* Unpin ASID */
arm64_mm_context_put(cd->mm);
+ mmdrop(cd->mm);
kfree(cd);
}
}