2017-04-23 10:23:42

by Pan Bian

Subject: [PATCH 1/1] iommu/amd: fix incorrect error handling

From: Pan Bian <[email protected]>

In function amd_iommu_bind_pasid(), the control flow jumps to label
out_free when pasid_state->mm and mm is NULL. And mmput(mm) is called.
In function mmput(mm), mm is referenced without validation. This will
result in a NULL dereference bug. This patch fixes the bug.

Signed-off-by: Pan Bian <[email protected]>
---
drivers/iommu/amd_iommu_v2.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 0633439..6629c47 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -696,9 +696,9 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,

out_unregister:
mmu_notifier_unregister(&pasid_state->mn, mm);
+ mmput(mm);

out_free:
- mmput(mm);
free_pasid_state(pasid_state);

out:
--
1.9.1

2017-04-24 10:39:13

by Joerg Roedel

Subject: Re: [PATCH 1/1] iommu/amd: fix incorrect error handling

On Sun, Apr 23, 2017 at 06:23:21PM +0800, Pan Bian wrote:
> From: Pan Bian <[email protected]>
>
> In function amd_iommu_bind_pasid(), the control flow jumps to label
> out_free when pasid_state->mm and mm is NULL. And mmput(mm) is called.
> In function mmput(mm), mm is referenced without validation. This will
> result in a NULL dereference bug. This patch fixes the bug.
>
> Signed-off-by: Pan Bian <[email protected]>

Applied, thanks.