• Roland Dreier's avatar
    net: Add default_mtu() methods to blackhole dst_ops · ec831ea7
    Roland Dreier authored
    When an IPSEC SA is still being set up, __xfrm_lookup() will return
    -EREMOTE and so ip_route_output_flow() will return a blackhole route.
    This can happen in a sndmsg call, and after d33e4553 ("net: Abstract
    default MTU metric calculation behind an accessor.") this leads to a
    crash in ip_append_data() because the blackhole dst_ops have no
    default_mtu() method and so dst_mtu() calls a NULL pointer.
    
    Fix this by adding default_mtu() methods (that simply return 0, matching
    the old behavior) to the blackhole dst_ops.
    
    The IPv4 part of this patch fixes a crash that I saw when using an IPSEC
    VPN; the IPv6 part is untested because I don't have an IPv6 VPN, but it
    looks to be needed as well.
    Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    ec831ea7
route.c 82.1 KB