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From: Marc Zyngier <maz@kernel.org>
To: Dinghao Liu <dinghao.liu@zju.edu.cn>
Cc: "Toan Le" <toan@os.amperecomputing.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Duc Dang" <dhdang@apm.com>, "Tanmay Inamdar" <tinamdar@apm.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI: xgene-msi: Fix a potential UAF in xgene_msi_probe
Date: Mon, 25 Sep 2023 10:40:48 +0100	[thread overview]
Message-ID: <87o7hqmvz3.wl-maz@kernel.org> (raw)
In-Reply-To: <20230925062133.14170-1-dinghao.liu@zju.edu.cn>

On Mon, 25 Sep 2023 07:21:32 +0100,
Dinghao Liu <dinghao.liu@zju.edu.cn> wrote:
> 
> xgene_allocate_domains() will call irq_domain_remove() to free
> msi->inner_domain on failure. However, its caller, xgene_msi_probe(),
> will also call irq_domain_remove() through xgene_msi_remove() on the
> same failure, which may lead to a use-after-free. Set the freed pointer
> to NULL to fix this issue.
> 
> Fixes: dcd19de36775 ("PCI: xgene: Add APM X-Gene v1 PCIe MSI/MSIX termination driver")
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>  drivers/pci/controller/pci-xgene-msi.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
> index 3ce38dfd0d29..c0192c5ff0f3 100644
> --- a/drivers/pci/controller/pci-xgene-msi.c
> +++ b/drivers/pci/controller/pci-xgene-msi.c
> @@ -253,6 +253,7 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
>  
>  	if (!msi->msi_domain) {
>  		irq_domain_remove(msi->inner_domain);
> +		msi->inner_domain = NULL;
>  		return -ENOMEM;
>  	}

Why can't we just drop the irq_domain_remove() call here instead, and
simply rely on xgene_msi_remove() to do the right thing? Something
like the untested patch below.

Thanks,

	M.

diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
index 0234e528b9a5..f98c9eb7bebf 100644
--- a/drivers/pci/controller/pci-xgene-msi.c
+++ b/drivers/pci/controller/pci-xgene-msi.c
@@ -251,10 +251,8 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
 						    &xgene_msi_domain_info,
 						    msi->inner_domain);
 
-	if (!msi->msi_domain) {
-		irq_domain_remove(msi->inner_domain);
+	if (!msi->msi_domain)
 		return -ENOMEM;
-	}
 
 	return 0;
 }

-- 
Without deviation from the norm, progress is not possible.

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Dinghao Liu <dinghao.liu@zju.edu.cn>
Cc: "Toan Le" <toan@os.amperecomputing.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Duc Dang" <dhdang@apm.com>, "Tanmay Inamdar" <tinamdar@apm.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI: xgene-msi: Fix a potential UAF in xgene_msi_probe
Date: Mon, 25 Sep 2023 10:40:48 +0100	[thread overview]
Message-ID: <87o7hqmvz3.wl-maz@kernel.org> (raw)
In-Reply-To: <20230925062133.14170-1-dinghao.liu@zju.edu.cn>

On Mon, 25 Sep 2023 07:21:32 +0100,
Dinghao Liu <dinghao.liu@zju.edu.cn> wrote:
> 
> xgene_allocate_domains() will call irq_domain_remove() to free
> msi->inner_domain on failure. However, its caller, xgene_msi_probe(),
> will also call irq_domain_remove() through xgene_msi_remove() on the
> same failure, which may lead to a use-after-free. Set the freed pointer
> to NULL to fix this issue.
> 
> Fixes: dcd19de36775 ("PCI: xgene: Add APM X-Gene v1 PCIe MSI/MSIX termination driver")
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
>  drivers/pci/controller/pci-xgene-msi.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
> index 3ce38dfd0d29..c0192c5ff0f3 100644
> --- a/drivers/pci/controller/pci-xgene-msi.c
> +++ b/drivers/pci/controller/pci-xgene-msi.c
> @@ -253,6 +253,7 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
>  
>  	if (!msi->msi_domain) {
>  		irq_domain_remove(msi->inner_domain);
> +		msi->inner_domain = NULL;
>  		return -ENOMEM;
>  	}

Why can't we just drop the irq_domain_remove() call here instead, and
simply rely on xgene_msi_remove() to do the right thing? Something
like the untested patch below.

Thanks,

	M.

diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
index 0234e528b9a5..f98c9eb7bebf 100644
--- a/drivers/pci/controller/pci-xgene-msi.c
+++ b/drivers/pci/controller/pci-xgene-msi.c
@@ -251,10 +251,8 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
 						    &xgene_msi_domain_info,
 						    msi->inner_domain);
 
-	if (!msi->msi_domain) {
-		irq_domain_remove(msi->inner_domain);
+	if (!msi->msi_domain)
 		return -ENOMEM;
-	}
 
 	return 0;
 }

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2023-09-25  9:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-25  6:21 [PATCH] PCI: xgene-msi: Fix a potential UAF in xgene_msi_probe Dinghao Liu
2023-09-25  6:21 ` Dinghao Liu
2023-09-25  9:40 ` Marc Zyngier [this message]
2023-09-25  9:40   ` Marc Zyngier
2023-09-26  2:21   ` dinghao.liu
2023-09-26  2:21     ` dinghao.liu
  -- strict thread matches above, loose matches on Subject: below --
2023-09-26  2:59 Dinghao Liu
2023-09-26  2:59 ` Dinghao Liu
2023-09-29  9:14 ` Marc Zyngier
2023-09-29  9:14   ` Marc Zyngier
2023-09-30  9:56   ` dinghao.liu
2023-09-30  9:56     ` dinghao.liu

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