From: Jason Gunthorpe <jgg@ziepe.ca>
To: Peiyang He <peiyang_he@smail.nju.edu.cn>
Cc: kevin.tian@intel.com, joro@8bytes.org, will@kernel.org,
robin.murphy@arm.com, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: Re: [BUG] iommufd/selftest: fault injection in iommufd_get_object can trigger a teardown UAF
Date: Mon, 13 Jul 2026 14:23:36 -0300 [thread overview]
Message-ID: <20260713172336.GF3133966@ziepe.ca> (raw)
In-Reply-To: <870BB9ADBBEDDD1A+37c5bfab-ad32-4fc5-a302-57c81a8432b5@smail.nju.edu.cn>
On Fri, Jul 10, 2026 at 01:46:55PM +0800, Peiyang He wrote:
> Hello Linux kernel developers and maintainers,
>
> We found a KMSAN use-after-free in iommu_device_release_dma_owner
> warning when fuzzing IOMMUFD with selftest with Syzkaller.
>
> After our digging, we believe this UAF has limited impact, but it
> exposes a possible improvement on how fault injection is handled in
> iommufd_device_pre_destroy().
>
> The root cause for this UAF is that iommufd_device_pre_destroy()
> uses the fault-injectable iommufd_get_object(), causing it to
> mistakenly assume that the vdev destruction has been taken over by
> another thread. More detailed analysis will be given below.
Yeah, I made a different fix for this than you suggested. See the
patch I'll post..
Thanks,
Jason
prev parent reply other threads:[~2026-07-13 17:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-10 5:46 [BUG] iommufd/selftest: fault injection in iommufd_get_object can trigger a teardown UAF Peiyang He
2026-07-13 17:23 ` Jason Gunthorpe [this message]
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