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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Longfang Liu <liulongfang@huawei.com>,
	Yishai Hadas <yishaih@nvidia.com>,
	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] vfio: hisi_acc_vfio_pci: fix integer overflow check in hisi_acc_vf_resume_write()
Date: Tue, 5 Jul 2022 15:06:49 -0300	[thread overview]
Message-ID: <20220705180649.GI23621@ziepe.ca> (raw)
In-Reply-To: <YsP+2CWqMudArkqF@kili>

On Tue, Jul 05, 2022 at 12:05:28PM +0300, Dan Carpenter wrote:
> The casting on this makes the integer overflow check slightly wrong.
> "len" is an unsigned long. "*pos" and "requested_length" are signed
> long longs.  Imagine "len" is ULONG_MAX and "*pos" is 2.
> "ULONG_MAX + 2 = 1". 

I wonder if this can happen, len is a kernel controlled value bounded
by a memory allocation..

> Fixes: b0eed085903e ("hisi_acc_vfio_pci: Add support for VFIO live migration")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---

This code was copy and pasted from drivers/vfio/pci/mlx5/main.c, so it
should be fixed too

> It is strange that we are doing:
> 
> 	pos = &filp->f_pos;
>
> instead of using the passed in value of pos.  

IIRC the way we have the struct file configured the pos argument is
NULL.

Jason

  reply	other threads:[~2022-07-05 18:06 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-05  9:05 [PATCH] vfio: hisi_acc_vfio_pci: fix integer overflow check in hisi_acc_vf_resume_write() Dan Carpenter
2022-07-05 18:06 ` Jason Gunthorpe [this message]
2022-07-06  5:51   ` Dan Carpenter
2022-07-06 16:18     ` Jason Gunthorpe
2022-07-07 14:58       ` Dan Carpenter

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