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iommu/arm-smmu-v3-sva: Fix mm use-after-free
[ Upstream commitcbd23144f7
] 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:32784a9562
("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
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parent
e2722f60c5
commit
e3cbbdbff8
1 changed files with 11 additions and 2 deletions
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@ -6,6 +6,7 @@
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#include <linux/mm.h>
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#include <linux/mmu_context.h>
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#include <linux/mmu_notifier.h>
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#include <linux/sched/mm.h>
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#include <linux/slab.h>
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#include "arm-smmu-v3.h"
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@ -96,9 +97,14 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
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struct arm_smmu_ctx_desc *cd;
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struct arm_smmu_ctx_desc *ret = NULL;
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/* Don't free the mm until we release the ASID */
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mmgrab(mm);
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asid = arm64_mm_context_get(mm);
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if (!asid)
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return ERR_PTR(-ESRCH);
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if (!asid) {
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err = -ESRCH;
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goto out_drop_mm;
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}
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cd = kzalloc(sizeof(*cd), GFP_KERNEL);
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if (!cd) {
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@ -165,6 +171,8 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
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kfree(cd);
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out_put_context:
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arm64_mm_context_put(mm);
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out_drop_mm:
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mmdrop(mm);
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return err < 0 ? ERR_PTR(err) : ret;
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}
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@ -173,6 +181,7 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
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if (arm_smmu_free_asid(cd)) {
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/* Unpin ASID */
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arm64_mm_context_put(cd->mm);
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mmdrop(cd->mm);
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kfree(cd);
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}
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}
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