On Sun, Jan 13, 2019 at 1:31 PM Oliver Hartkopp <socketcan@xxxxxxxxxxxx> wrote: > > Kyungtae Kim detected a potential integer overflow in bcm_[rx|tx]_setup() > when the conversion into ktime multiplies the given value with NSEC_PER_USEC > (1000). > > Reference: https://marc.info/?l=linux-can&m=154732118819828&w=2 > > Add a check for the given tv_usec, so that the value stays below one second. > Additionally limit the tv_sec value to a reasonable value for CAN related > use-cases of 400 days and ensure all values to be positive. > > Reported-by: Kyungtae Kim <kt0755@xxxxxxxxx> > Tested-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Tested-by: Kyungtae Kim <kt0755@xxxxxxxxx> > Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> > Cc: linux-stable <stable@xxxxxxxxxxxxxxx> # >= 2.6.26 > --- > net/can/bcm.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/net/can/bcm.c b/net/can/bcm.c > index 0af8f0db892a..d4ae0a1471f3 100644 > --- a/net/can/bcm.c > +++ b/net/can/bcm.c > @@ -67,6 +67,9 @@ > */ > #define MAX_NFRAMES 256 > > +/* limit timers to 400 days for sending/timeouts */ > +#define BCM_TIMER_SEC_MAX (400*24*60*60) > + > /* use of last_frames[index].flags */ > #define RX_RECV 0x40 /* received data for this element */ > #define RX_THR 0x80 /* element not been sent due to throttle feature */ > @@ -140,6 +143,22 @@ static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv) > return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC); > } > > +/* check limitations for timeval provided by user */ > +static int bcm_is_invalid_tv(struct bcm_msg_head *msg_head) > +{ > + if ((msg_head->ival1.tv_sec < 0) || > + (msg_head->ival1.tv_sec > BCM_TIMER_SEC_MAX) || > + (msg_head->ival1.tv_usec < 0) || > + (msg_head->ival1.tv_usec >= USEC_PER_SEC) || > + (msg_head->ival2.tv_sec < 0) || > + (msg_head->ival2.tv_sec > BCM_TIMER_SEC_MAX) || > + (msg_head->ival2.tv_usec < 0) || > + (msg_head->ival2.tv_usec >= USEC_PER_SEC)) > + return 1; > + > + return 0; > +} > + > #define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU) > #define OPSIZ sizeof(struct bcm_op) > #define MHSIZ sizeof(struct bcm_msg_head) > @@ -873,6 +892,10 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, > if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES) > return -EINVAL; > > + /* check timeval limitations */ > + if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head)) > + return -EINVAL; > + > /* check the given can_id */ > op = bcm_find_op(&bo->tx_ops, msg_head, ifindex); > if (op) { > @@ -1053,6 +1076,10 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, > (!(msg_head->can_id & CAN_RTR_FLAG)))) > return -EINVAL; > > + /* check timeval limitations */ > + if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head)) > + return -EINVAL; > + > /* check the given can_id */ > op = bcm_find_op(&bo->rx_ops, msg_head, ifindex); > if (op) { > -- > 2.20.1 >
