From: Xin Long <lucien.xin@xxxxxxxxx>
Date: Mon, 18 Mar 2019 19:58:29 +0800
> Now sctp_copy_descendant() copies pd_lobby from old sctp scok to new
> sctp sock. If sctp_sock_migrate() returns error, it will panic when
> releasing new sock and trying to purge pd_lobby due to the incorrect
> pointers in pd_lobby.
>
> [ 120.485116] kasan: CONFIG_KASAN_INLINE enabled
> [ 120.486270] kasan: GPF could be caused by NULL-ptr deref or user
> [ 120.509901] Call Trace:
> [ 120.510443] sctp_ulpevent_free+0x1e8/0x490 [sctp]
> [ 120.511438] sctp_queue_purge_ulpevents+0x97/0xe0 [sctp]
> [ 120.512535] sctp_close+0x13a/0x700 [sctp]
> [ 120.517483] inet_release+0xdc/0x1c0
> [ 120.518215] __sock_release+0x1d2/0x2a0
> [ 120.519025] sctp_do_peeloff+0x30f/0x3c0 [sctp]
>
> We fix it by not copying sctp_sock pd_lobby in sctp_copy_descendan(),
> and skb_queue_head_init() can also be removed in sctp_sock_migrate().
>
> Reported-by: syzbot+85e0b422ff140b03672a@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 89664c623617 ("sctp: sctp_sock_migrate() returns error if sctp_bind_addr_dup() fails")
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Applied and looks to not need -stable backporting. Let me know if you
disagree.
