4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <[email protected]> [ Upstream commit 657831ffc38e30092a2d5f03d385d710eb88b09a ] 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 8b485ce69876 ("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 <[email protected]> Reported-by: Pray3r <[email protected]> Reported-by: Andrey Konovalov <[email protected]> Tested-by: Andrey Konovalov <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/ipv4/inet_connection_sock.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -665,6 +665,8 @@ struct sock *inet_csk_clone_lock(const s /* 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));
