• Oliver Hartkopp's avatar
    can: Fix data length code handling in rx path · c7cd606f
    Oliver Hartkopp authored
    A valid CAN dataframe can have a data length code (DLC) of 0 .. 8 data bytes.
    
    When reading the CAN controllers register the 4-bit value may contain values
    from 0 .. 15 which may exceed the reserved space in the socket buffer!
    
    The ISO 11898-1 Chapter 8.4.2.3 (DLC field) says that register values > 8
    should be reduced to 8 without any error reporting or frame drop.
    
    This patch introduces a new helper macro to cast a given 4-bit data length
    code (dlc) to __u8 and ensure the DLC value to be max. 8 bytes.
    
    The different handlings in the rx path of the CAN netdevice drivers are fixed.
    Signed-off-by: default avatarOliver Hartkopp <oliver@hartkopp.net>
    Signed-off-by: default avatarWolfgang Grandegger <wg@grandegger.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    c7cd606f
ems_usb.c 26.7 KB