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Message-ID: <b6585727108669e0c85e7871575c7700d69b5f5d.camel@redhat.com>
Subject: Re: [PATCH] RDMA/ucma: Fix Spectre v1 vulnerability
From:   Doug Ledford <dledford@redhat.com>
To:     "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        Jason Gunthorpe <jgg@ziepe.ca>
Cc:     linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Tue, 16 Oct 2018 12:49:43 -0400
In-Reply-To: <20181016145901.GA8811@embeddedor.com>
References: <20181016145901.GA8811@embeddedor.com>
Organization: Red Hat, Inc.
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On Tue, 2018-10-16 at 16:59 +0200, Gustavo A. R. Silva wrote:
> hdr.cmd can be indirectly controlled by user-space, hence leading to
> a potential exploitation of the Spectre variant 1 vulnerability.
>=20
> This issue was detected with the help of Smatch:
>=20
> drivers/infiniband/core/ucma.c:1686 ucma_write() warn: potential
> spectre issue 'ucma_cmd_table' [r] (local cap)
>=20
> Fix this by sanitizing hdr.cmd before using it to index
> ucm_cmd_table.
>=20
> Notice that given that speculation windows are large, the policy is
> to kill the speculation on the first load and not worry if it can be
> completed with a dependent load/store [1].
>=20
> [1] https://marc.info/?l=3Dlinux-kernel&m=3D152449131114778&w=3D2
>=20
> Cc: stable@vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Thanks, applied to for-rc.

--=20
Doug Ledford <dledford@redhat.com>
    GPG KeyID: B826A3330E572FDD
    Key fingerprint =3D AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

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