• Maciej Żenczykowski's avatar
    net: do not allow changing SO_REUSEADDR/SO_REUSEPORT on bound sockets · f396922d
    Maciej Żenczykowski authored
    It is not safe to do so because such sockets are already in the
    hash tables and changing these options can result in invalidating
    the tb->fastreuse(port) caching.
    
    This can have later far reaching consequences wrt. bind conflict checks
    which rely on these caches (for optimization purposes).
    
    Not to mention that you can currently end up with two identical
    non-reuseport listening sockets bound to the same local ip:port
    by clearing reuseport on them after they've already both been bound.
    
    There is unfortunately no EISBOUND error or anything similar,
    and EISCONN seems to be misleading for a bound-but-not-connected
    socket, so use EUCLEAN 'Structure needs cleaning' which AFAICT
    is the closest you can get to meaning 'socket in bad state'.
    (although perhaps EINVAL wouldn't be a bad choice either?)
    
    This does unfortunately run the risk of breaking buggy
    userspace programs...
    Signed-off-by: default avatarMaciej Żenczykowski <maze@google.com>
    Cc: Eric Dumazet <edumazet@google.com>
    Change-Id: I77c2b3429b2fdf42671eee0fa7a8ba721c94963b
    Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f396922d
sock.c 85.5 KB