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SubjectRe: [PATCH] IB/mlx4: Avoid field-overflowing memcpy()
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>

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