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From: Jason Gunthorpe <jgg@nvidia.com>
To: Shay Drory <shayd@nvidia.com>
Cc: Leon Romanovsky <leon@kernel.org>,
	Doug Ledford <dledford@redhat.com>,
	Krishna Kumar <krkumar2@in.ibm.com>,
	linux-rdma@vger.kernel.org, Sean Hefty <sean.hefty@intel.com>
Subject: Re: [PATCH rdma-next 2/3] RDMA/core: Fix check of device in rdma_listen()
Date: Thu, 22 Apr 2021 09:51:35 -0300	[thread overview]
Message-ID: <20210422125135.GV1370958@nvidia.com> (raw)
In-Reply-To: <1fca1133-8cdd-8b21-42cf-69d610b4f8f4@nvidia.com>

On Thu, Apr 22, 2021 at 03:44:55PM +0300, Shay Drory wrote:
> On 4/22/2021 14:28, Jason Gunthorpe wrote:
> 
> > On Sun, Apr 18, 2021 at 04:55:53PM +0300, Leon Romanovsky wrote:
> > > From: Shay Drory <shayd@nvidia.com>
> > > 
> > > rdma_listen() checks if device already attached to rdma_id_priv,
> > > based on the response the its decide to what to listen, however
> > > this is different when the listeners are canceled.
> > > 
> > > This leads to a mismatch between rdma_listen() and cma_cancel_operation(),
> > > and causes to bellow wild-memory-access. Fix it by aligning rdma_listen()
> > > according to the cma_cancel_operation().
> > So this is happening because the error unwind in rdma_bind_addr() is
> > taking the exit path and calling cma_release_dev()?
> > 
> > This allows rdma_listen() to be called with a bogus device pointer
> > which precipitates this UAF during destroy.
> > 
> > However, I think rdma_bind_addr() should not allow the bogus device
> > pointer to leak out at all, since the ULP could see it. It really is
> > invalid to have it present no matter what.
> > 
> > This would make cma_release_dev() and _cma_attach_to_dev()
> > symmetrical - what do you think?
> > 
> > diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> > index 2dc302a83014ae..91f6d968b46f65 100644
> > +++ b/drivers/infiniband/core/cma.c
> > @@ -474,6 +474,7 @@ static void cma_release_dev(struct rdma_id_private *id_priv)
> >   	list_del(&id_priv->list);
> >   	cma_dev_put(id_priv->cma_dev);
> >   	id_priv->cma_dev = NULL;
> > +	id_priv->id.device = NULL;
> >   	if (id_priv->id.route.addr.dev_addr.sgid_attr) {
> >   		rdma_put_gid_attr(id_priv->id.route.addr.dev_addr.sgid_attr);
> >   		id_priv->id.route.addr.dev_addr.sgid_attr = NULL;
> 
> I try that. this will break restrack_del() since restrack_del() is
> using id_priv->id.device and is being called before restrack_del():

Oh that is another bug, once cma_release_dev() is called there is no
refcount protecting the id.device and any access to it is invalid.

The order of rdma_restrack_del should be moved to be ahead of the
cma_release_dev, and we also can't have a restrack without a cma_dev
in the first place

Jason

  reply	other threads:[~2021-04-22 12:51 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-18 13:55 [PATCH rdma-next 0/3] CMA fixes Leon Romanovsky
2021-04-18 13:55 ` [PATCH rdma-next 1/3] RDMA/cma: Skip device which doesn't support CM Leon Romanovsky
2021-04-18 13:55 ` [PATCH rdma-next 2/3] RDMA/core: Fix check of device in rdma_listen() Leon Romanovsky
2021-04-22 11:28   ` Jason Gunthorpe
2021-04-22 12:44     ` Shay Drory
2021-04-22 12:51       ` Jason Gunthorpe [this message]
2021-04-22 13:01         ` Leon Romanovsky
2021-04-22 13:02           ` Jason Gunthorpe
2021-04-22 14:58             ` Leon Romanovsky
2021-04-22 16:18               ` Jason Gunthorpe
2021-04-25 13:17                 ` Leon Romanovsky
2021-04-18 13:55 ` [PATCH rdma-next 3/3] RDMA/core: Add CM to restrack after successful attachment to a device Leon Romanovsky
2021-04-21 23:59 ` [PATCH rdma-next 0/3] CMA fixes Jason Gunthorpe
2021-04-22  6:46   ` Leon Romanovsky

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