3.16.7-ckt6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> commit 9b1087aa5e86448fe6ad40a58964e35f3ba423d5 upstream. When changing flags in the CAN drivers ctrlmode the provided new content has to be checked whether the bits are allowed to be changed. The bits that are to be changed are given as a bitfield in cm->mask. Therefore checking against cm->flags is wrong as the content can hold any kind of values. The iproute2 tool sets the bits in cm->mask and cm->flags depending on the detected command line options. To be robust against bogus user space applications additionally sanitize the provided flags with the provided mask. Cc: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx> --- drivers/net/can/dev.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 4e3f7ea6d52d..9b04d0a9356d 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -730,10 +730,14 @@ static int can_changelink(struct net_device *dev, if (dev->flags & IFF_UP) return -EBUSY; cm = nla_data(data[IFLA_CAN_CTRLMODE]); - if (cm->flags & ~priv->ctrlmode_supported) + + /* check whether changed bits are allowed to be modified */ + if (cm->mask & ~priv->ctrlmode_supported) return -EOPNOTSUPP; + + /* clear bits to be modified and copy the flag values */ priv->ctrlmode &= ~cm->mask; - priv->ctrlmode |= cm->flags; + priv->ctrlmode |= (cm->flags & cm->mask); /* CAN_CTRLMODE_FD can only be set when driver supports FD */ if (priv->ctrlmode & CAN_CTRLMODE_FD) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html