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From: dinghao.liu@zju.edu.cn
To: "Marc Zyngier" <maz@kernel.org>
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: Tue, 26 Sep 2023 10:21:13 +0800 (GMT+08:00)	[thread overview]
Message-ID: <1c50637d.3e6d5.18acf4a638c.Coremail.dinghao.liu@zju.edu.cn> (raw)
In-Reply-To: <87o7hqmvz3.wl-maz@kernel.org>

> 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;
>  }

Thanks for your advice! This patch is more concise. I will resend a new patch soon.

Regards,
Dinghao
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  reply	other threads:[~2023-09-26  2:22 UTC|newest]

Thread overview: 6+ 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  9:40 ` Marc Zyngier
2023-09-26  2:21   ` dinghao.liu [this message]
  -- strict thread matches above, loose matches on Subject: below --
2023-09-26  2:59 Dinghao Liu
2023-09-29  9:14 ` Marc Zyngier
2023-09-30  9:56   ` dinghao.liu

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