can: add sanity checks

Even though the CAN netlayer only deals with CAN netdevices, the 
netlayer interface to the userspace and to the device layer should 
perform some sanity checks.

This patch adds several sanity checks that mainly prevent userspace apps 
to send broken content into the system that may be misinterpreted by 
some other userspace application.

Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Acked-by: Andre Naujoks <nautsch@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/can/raw.c b/net/can/raw.c
index 69877b8e7e9c..3e46ee36a1aa 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -632,6 +632,9 @@ static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
         } else
                 ifindex = ro->ifindex;
 
+        if (size != sizeof(struct can_frame))
+                return -EINVAL;
+
         dev = dev_get_by_index(&init_net, ifindex);
         if (!dev)
                 return -ENXIO;