On 2/13/2024 1:36 PM, Dmitry Baryshkov wrote:
On Tue, 13 Feb 2024 at 08:27, Pratyush Brahma <quic_pbrahma@xxxxxxxxxxx> wrote:
Currently, during arm smmu probe, struct arm_smmu_device pointer
is allocated. The pointer is reallocated to a new struct qcom_smmu in
qcom_smmu_create() with devm_krealloc() which frees the smmu device
after copying the data into the new pointer.
The freed pointer is then passed again in devm_of_platform_populate()
inside qcom_smmu_create() which causes a use-after-free issue.
Fix the use-after-free issue by reassigning the old pointer to
the new pointer where the struct was copied by devm_krealloc().
Signed-off-by: Pratyush Brahma <quic_pbrahma@xxxxxxxxxxx>
Missing Fixes tag.
Haven't added as the patchset in-reply-to hasn't been merged to
linux-next. Please refer my next reply.
---
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index ed5ed5da7740..49eaeed6a91c 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -710,6 +710,7 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
qsmmu = devm_krealloc(smmu->dev, smmu, sizeof(*qsmmu), GFP_KERNEL);
if (!qsmmu)
return ERR_PTR(-ENOMEM);
+ smmu = &qsmmu->smmu;
qsmmu->smmu.impl = impl;
qsmmu->data = data;
@@ -719,7 +720,7 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
if (ret)
return ERR_PTR(ret);
What is the tree that you have been developing this against? I don't
see this part of the code in the linux-next.
This is in reply to the patchset at:
https://lore.kernel.org/all/20240201210529.7728-4-quic_c_gdjako@xxxxxxxxxxx
The aforementioned patchset introduces this bug. This is a suggested fix
to the bug.
- return &qsmmu->smmu;
+ return smmu;
}
/* Implementation Defined Register Space 0 register offsets */
--
2.17.1
Thanks,
Pratyush
