On Mon, Sep 26, 2022 at 05:39:53PM -0700, Kees Cook wrote: > To work around a misbehavior of the compiler's ability to see into > composite flexible array structs (as detailed in the coming memcpy() > hardening series[1]), split the memcpy() of the header and the payload > so no false positive run-time overflow warning will be generated. > > [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@xxxxxxxxxxxx/ > > Cc: Alexandra Winter <wintera@xxxxxxxxxxxxx> > Cc: Wenjia Zhang <wenjia@xxxxxxxxxxxxx> > Cc: Heiko Carstens <hca@xxxxxxxxxxxxx> > Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> > Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> > Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> > Cc: Sven Schnelle <svens@xxxxxxxxxxxxx> > Cc: linux-s390@xxxxxxxxxxxxxxx > Cc: netdev@xxxxxxxxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Thanks! -- Gustavo > --- > drivers/s390/net/qeth_l2_main.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c > index 2d4436cbcb47..0ce635b7b472 100644 > --- a/drivers/s390/net/qeth_l2_main.c > +++ b/drivers/s390/net/qeth_l2_main.c > @@ -1530,8 +1530,8 @@ static void qeth_addr_change_event(struct qeth_card *card, > else > INIT_DELAYED_WORK(&data->dwork, qeth_l2_dev2br_worker); > data->card = card; > - memcpy(&data->ac_event, hostevs, > - sizeof(struct qeth_ipacmd_addr_change) + extrasize); > + data->ac_event = *hostevs; > + memcpy(data->ac_event.entry, hostevs->entry, extrasize); > queue_delayed_work(card->event_wq, &data->dwork, 0); > } > > -- > 2.34.1 >
