From 636d25d557d1073281013c43e4ff4737692da2d4 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Mon, 18 Mar 2019 19:58:29 +0800 Subject: [PATCH] sctp: not copy sctp_sock pd_lobby in sctp_copy_descendant 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@syzkaller.appspotmail.com Fixes: 89664c623617 ("sctp: sctp_sock_migrate() returns error if sctp_bind_addr_dup() fails") Signed-off-by: Xin Long Signed-off-by: David S. Miller --- net/sctp/socket.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 6140471efd4b..65b538604c5b 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -9169,7 +9169,7 @@ static inline void sctp_copy_descendant(struct sock *sk_to, { int ancestor_size = sizeof(struct inet_sock) + sizeof(struct sctp_sock) - - offsetof(struct sctp_sock, auto_asconf_list); + offsetof(struct sctp_sock, pd_lobby); if (sk_from->sk_family == PF_INET6) ancestor_size += sizeof(struct ipv6_pinfo); @@ -9253,7 +9253,6 @@ static int sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, * 2) Peeling off partial delivery; keep pd_lobby in new pd_lobby. * 3) Peeling off non-partial delivery; move pd_lobby to receive_queue. */ - skb_queue_head_init(&newsp->pd_lobby); atomic_set(&sctp_sk(newsk)->pd_mode, assoc->ulpq.pd_mode); if (atomic_read(&sctp_sk(oldsk)->pd_mode)) { -- 2.30.2