linux-kernel - Re: [PATCH] iommu/s390: Implement blocking domain

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3ac48be62da0afdca6923c7a09fa303cf2c76ad2.camel@linux.ibm.com>
Date: Tue, 06 Aug 2024 16:10:30 +0200
From: Niklas Schnelle <schnelle@...ux.ibm.com>
To: Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin
 Murphy <robin.murphy@....com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
Cc: Gerd Bayer <gbayer@...ux.ibm.com>, Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev
 <agordeev@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>, Joerg Roedel
 <jroedel@...e.de>,
        iommu@...ts.linux.dev, linux-kernel@...r.kernel.org,
        linux-s390@...r.kernel.org
Subject: Re: [PATCH] iommu/s390: Implement blocking domain

On Tue, 2024-08-06 at 15:45 +0200, Niklas Schnelle wrote:
> This fixes a crash when surprise hot-unplugging a PCI device. This crash
> happens because during hot-unplug __iommu_group_set_domain_nofail()
> attaching the default domain fails when the platform no longer
> recognizes the device as it has already been removed and we end up with
> a NULL domain pointer and UAF. This is exactly the case referred to in
> the second comment in __iommu_device_set_domain() and just as stated
> there if we can instead attach the blocking domain the UAF is prevented
> as this can handle the already removed device. Implement the blocking
> domain to use this handling. This would still leave us with a warning
> for a failed attach. As failing to attach when the device is no longer
> present is expected behavior turn this into an explicit -ENODEV error
> and don't warn for it. Also change the error return for a NULL zdev to
> -EIO as we don't want to ignore this case that would be a serious bug.
> 
> Fixes: c76c067e488c ("s390/pci: Use dma-iommu layer")
> Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com>
> ---
> Note: I somewhat suspect this to be related to the following discussion
> or at least we have seen the same backtraces in reports that we suspect
> to be caused by the issue fixed with this patch. In the case I was able
> to reproduce with vfio-pci pass-through to a KVM guest I got a different
> trace though.

Forgot the link:
https://lore.kernel.org/all/8743264a-9700-4227-a556-5f931c720211@huawei.com/

> 
> Organizational note: I'll be on vacation starting Thursday. Matt will
> then take over and sent new revisions as necessary.
> ---
>  drivers/iommu/iommu.c      |  7 ++++---
---8<---