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+85e0b422ff140b036...@syzkaller.appspotmail.com
Fixes: 89664c623617 ("sctp: sctp_sock_migrate() returns error if
sctp_bind_addr_dup() fails")
Signed-off-by: Xin Long <lucien....@gmail.com>
---
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 6140471..65b5386 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)) {
--
2.1.0
