Skip to content
Permalink
Browse files

dccp/tcp: do not inherit mc_list from parent

syzkaller found a way to trigger double frees from ip_mc_drop_socket()

It turns out that leave a copy of parent mc_list at accept() time,
which is very bad.

Very similar to commit 8b485ce ("tcp: do not inherit
fastopen_req from parent")

Initial report from Pray3r, completed by Andrey one.
Thanks a lot to them !

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Pray3r <pray3r.z@gmail.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information...
Eric Dumazet authored and davem330 committed May 9, 2017
1 parent e735da5 commit 657831ffc38e30092a2d5f03d385d710eb88b09a
Showing with 2 additions and 0 deletions.
  1. +2 −0 net/ipv4/inet_connection_sock.c
@@ -794,6 +794,8 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
/* listeners have SOCK_RCU_FREE, not the children */
sock_reset_flag(newsk, SOCK_RCU_FREE);

inet_sk(newsk)->mc_list = NULL;

newsk->sk_mark = inet_rsk(req)->ir_mark;
atomic64_set(&newsk->sk_cookie,
atomic64_read(&inet_rsk(req)->ir_cookie));

0 comments on commit 657831f

Please sign in to comment.
You can’t perform that action at this time.