• Xin Long's avatar
    sctp: change sctp_prot .no_autobind with true · 2770f80a
    Xin Long authored
    [ Upstream commit 63dfb793 ]
    
    syzbot reported a memory leak:
    
      BUG: memory leak, unreferenced object 0xffff888120b3d380 (size 64):
      backtrace:
    
        [...] slab_alloc mm/slab.c:3319 [inline]
        [...] kmem_cache_alloc+0x13f/0x2c0 mm/slab.c:3483
        [...] sctp_bucket_create net/sctp/socket.c:8523 [inline]
        [...] sctp_get_port_local+0x189/0x5a0 net/sctp/socket.c:8270
        [...] sctp_do_bind+0xcc/0x200 net/sctp/socket.c:402
        [...] sctp_bindx_add+0x4b/0xd0 net/sctp/socket.c:497
        [...] sctp_setsockopt_bindx+0x156/0x1b0 net/sctp/socket.c:1022
        [...] sctp_setsockopt net/sctp/socket.c:4641 [inline]
        [...] sctp_setsockopt+0xaea/0x2dc0 net/sctp/socket.c:4611
        [...] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3147
        [...] __sys_setsockopt+0x10f/0x220 net/socket.c:2084
        [...] __do_sys_setsockopt net/socket.c:2100 [inline]
    
    It was caused by when sending msgs without binding a port, in the path:
    inet_sendmsg() -> inet_send_prepare() -> inet_autobind() ->
    .get_port/sctp_get_port(), sp->bind_hash will be set while bp->port is
    not. Later when binding another port by sctp_setsockopt_bindx(), a new
    bucket will be created as bp->port is not set.
    
    sctp's autobind is supposed to call sctp_autobind() where it does all
    things including setting bp->port. Since sctp_autobind() is called in
    sctp_sendmsg() if the sk is not yet bound, it should have skipped the
    auto bind.
    
    THis patch is to avoid calling inet_autobind() in inet_send_prepare()
    by changing sctp_prot .no_autobind with true, also remove the unused
    .get_port.
    
    Reported-by: syzbot+d44f7bbebdea49dbc84a@syzkaller.appspotmail.com
    Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
    Acked-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    2770f80a
socket.c 247 KB