From: Leon Romanovsky <leon@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Jack Morgenstein <jackm@nvidia.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Yishai Hadas <yishaih@nvidia.com>,
Doug Ledford <dledford@redhat.com>,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] IB/mlx4: Avoid field-overflowing memcpy()
Date: Mon, 21 Jun 2021 11:11:46 +0300 [thread overview]
Message-ID: <YNBJwnwaS6w9A0x4@unreal> (raw)
In-Reply-To: <202106171239.C425161E8@keescook>
On Thu, Jun 17, 2021 at 12:46:43PM -0700, Kees Cook wrote:
> On Thu, Jun 17, 2021 at 10:24:58AM +0300, Leon Romanovsky wrote:
> > On Wed, Jun 16, 2021 at 01:37:44PM -0700, Kees Cook wrote:
> > > In preparation for FORTIFY_SOURCE performing compile-time and run-time
> > > field bounds checking for memcpy(), memmove(), and memset(), avoid
> > > intentionally writing across neighboring array fields.
> > >
> > > Use the ether_addr_copy() helper instead, as already done for smac.
> > >
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > ---
> > > drivers/infiniband/hw/mlx4/qp.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
> > > index 2ae22bf50016..4a2ef7daaded 100644
> > > --- a/drivers/infiniband/hw/mlx4/qp.c
> > > +++ b/drivers/infiniband/hw/mlx4/qp.c
> > > @@ -3144,7 +3144,7 @@ static int build_mlx_header(struct mlx4_ib_qp *qp, const struct ib_ud_wr *wr,
> > > mlx->sched_prio = cpu_to_be16(pcp);
> > >
> > > ether_addr_copy(sqp->ud_header.eth.smac_h, ah->av.eth.s_mac);
> > > - memcpy(sqp->ud_header.eth.dmac_h, ah->av.eth.mac, 6);
> > > + ether_addr_copy(sqp->ud_header.eth.dmac_h, ah->av.eth.mac);
> > > memcpy(&ctrl->srcrb_flags16[0], ah->av.eth.mac, 2);
> > > memcpy(&ctrl->imm, ah->av.eth.mac + 2, 4);
> >
> > I don't understand the last three lines. We are copying 6 bytes to
> > ah->av.eth.mac and immediately after that overwriting them.
>
> I'm not following (the memcpy() is replaced by ether_addr_copy()).
Forget it, it was me who mixed src with dst in the memcpy() signature.
Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
next prev parent reply other threads:[~2021-06-21 8:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-16 20:37 [PATCH] IB/mlx4: Avoid field-overflowing memcpy() Kees Cook
2021-06-17 7:24 ` Leon Romanovsky
2021-06-17 19:46 ` Kees Cook
2021-06-21 8:11 ` Leon Romanovsky [this message]
2021-06-22 0:05 ` Jason Gunthorpe
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