• Stefano Brivio's avatar
    ipv6/ndisc: Preserve IPv6 control buffer if protocol error handlers are called · ee1abcf6
    Stefano Brivio authored
    Commit a61bbcf2 ("[NET]: Store skb->timestamp as offset to a base
    timestamp") introduces a neighbour control buffer and zeroes it out in
    ndisc_rcv(), as ndisc_recv_ns() uses it.
    
    Commit f2776ff0 ("[IPV6]: Fix address/interface handling in UDP and
    DCCP, according to the scoping architecture.") introduces the usage of the
    IPv6 control buffer in protocol error handlers (e.g. inet6_iif() in
    present-day __udp6_lib_err()).
    
    Now, with commit b94f1c09 ("ipv6: Use icmpv6_notify() to propagate
    redirect, instead of rt6_redirect()."), we call protocol error handlers
    from ndisc_redirect_rcv(), after the control buffer is already stolen and
    some parts are already zeroed out. This implies that inet6_iif() on this
    path will always return zero.
    
    This gives unexpected results on UDP socket lookup in __udp6_lib_err(), as
    we might actually need to match sockets for a given interface.
    
    Instead of always claiming the control buffer in ndisc_rcv(), do that only
    when needed.
    
    Fixes: b94f1c09 ("ipv6: Use icmpv6_notify() to propagate redirect, instead of rt6_redirect().")
    Signed-off-by: default avatarStefano Brivio <sbrivio@redhat.com>
    Reviewed-by: default avatarSabrina Dubroca <sd@queasysnail.net>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    ee1abcf6
ndisc.c 48 KB