diff options
| author | Jean-Philippe Brucker | 2022-04-26 14:04:45 +0100 |
|---|---|---|
| committer | Will Deacon | 2022-05-06 16:25:39 +0100 |
| commit | cbd23144f7662b00bcde32a938c4a4057e476d68 (patch) | |
| tree | 258cc5bf56bc772f6db3fef3915dbc3820f1bdf3 /drivers/iommu | |
| parent | b131fa8c1d2afd05d0b7598621114674289c2fbb (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.c | 13 |
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); } } |