2023-12-19 10:02:35

by Alexander Sapozhnikov

Subject: [PATCH] iommu: amd: NULL value may be dereferenced

Pointer 'dom' which was dereferenced at iommu.c:1993
is compared to NULL value at iommu.c:1998.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Alexander Sapozhnikov <[email protected]>
---
drivers/iommu/amd/iommu.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index a0924144bac8..64a88e67be9c 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1985,6 +1985,9 @@ static void amd_iommu_domain_free(struct iommu_domain *dom)
{
struct protection_domain *domain;

+ if (!dom)
+ return;
+
domain = to_pdomain(dom);

if (domain->dev_cnt > 0)
--
2.40.1

2023-12-20 10:25:13

by Suravee Suthikulpanit

Subject: Re: [PATCH] iommu: amd: NULL value may be dereferenced

On 12/19/2023 5:02 PM, Alexander Sapozhnikov wrote:
> Pointer 'dom' which was dereferenced at iommu.c:1993
> is compared to NULL value at iommu.c:1998.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Alexander Sapozhnikov <[email protected]>
> ---
> drivers/iommu/amd/iommu.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index a0924144bac8..64a88e67be9c 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -1985,6 +1985,9 @@ static void amd_iommu_domain_free(struct iommu_domain *dom)
> {
> struct protection_domain *domain;
>
> + if (!dom)
> + return;
> +
> domain = to_pdomain(dom);
>
> if (domain->dev_cnt > 0)

This check is already added in the following commit in the next branch
of the iommu.git repo.

3f4b87b959ea "iommu/amd: Make use of domain_alloc and domain_free"
(https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/commit/?h=next&id=3f4b87b959eab362b89fce6ceb9d1badd102e5ea)

Thanks,
Suravee