From: Jason Gunthorpe <jgg@ziepe.ca>
To: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Ira Weiny <ira.weiny@intel.com>,
dledford@redhat.com, Jann Horn <jannh@google.com>,
linux-rdma@vger.kernel.org,
Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>,
linux-mm@kvack.org
Subject: Re: [PATCH for-rc v2] IB/hfi1: Move cached value of mm into handler
Date: Thu, 12 Nov 2020 20:02:05 -0400 [thread overview]
Message-ID: <20201113000205.GX244516@ziepe.ca> (raw)
In-Reply-To: <ba7df075-ab50-3344-aacb-656ae10b517a@cornelisnetworks.com>
On Thu, Nov 12, 2020 at 05:08:22PM -0500, Dennis Dalessandro wrote:
> On 11/12/2020 5:06 PM, Dennis Dalessandro wrote:
> > On 11/12/2020 12:14 PM, Ira Weiny wrote:
> > > On Wed, Nov 11, 2020 at 09:58:37PM -0500, Dennis Dalessandro wrote:
> > > > Two earlier bug fixes have created a security problem in the hfi1
> > > > driver. One fix aimed to solve an issue where current->mm was not valid
> > > > when closing the hfi1 cdev. It attempted to do this by saving a cached
> > > > value of the current->mm pointer at file open time. This is a problem if
> > > > another process with access to the FD calls in via write() or ioctl() to
> > > > pin pages via the hfi driver. The other fix tried to solve a use after
> > > > free by taking a reference on the mm. This was just wrong because its
> > > > possible for a race condition between one process with an mm that opened
> > > > the cdev if it was accessing via an IOCTL, and another process
> > > > attempting to close the cdev with a different current->mm.
> > >
> > > Again I'm still not seeing the race here. It is entirely possible
> > > that the fix
> > > I was trying to do way back was mistaken too... ;-) I would just
> > > delete the
> > > last 2 sentences... and/or reference the commit of those fixes and help
> > > explain this more.
> >
> > I was attempting to refer to [1], the email that started all of this.
>
> That link should be:
> [1] https://marc.info/?l=linux-rdma&m=159891753806720&w=2
And consistently use lore.kernel.org links please :\
Jason
next prev parent reply other threads:[~2020-11-13 0:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 2:58 [PATCH for-rc v2] IB/hfi1: Move cached value of mm into handler Dennis Dalessandro
2020-11-12 17:14 ` Ira Weiny
2020-11-12 22:06 ` Dennis Dalessandro
2020-11-12 22:08 ` Dennis Dalessandro
2020-11-13 0:02 ` Jason Gunthorpe [this message]
2020-11-13 0:33 ` Ira Weiny
2020-11-13 13:37 ` Dennis Dalessandro
2020-11-13 18:31 ` Ira Weiny
2020-11-13 0:01 ` Jason Gunthorpe
2020-11-13 0:42 ` Ira Weiny
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