From e3fff011db7dd80d53b6bda48bcf2313918aa7a8 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: <0b716bdb952b678d9bb5eb32198dbc82ec492df2.1515173964.git.jan.steffens@gmail.com> References: <0b716bdb952b678d9bb5eb32198dbc82ec492df2.1515173964.git.jan.steffens@gmail.com> From: Mohamed Ghannam Date: Tue, 5 Dec 2017 20:58:35 +0000 Subject: [PATCH 3/6] dccp: CVE-2017-8824: use-after-free in DCCP code Whenever the sock object is in DCCP_CLOSED state, dccp_disconnect() must free dccps_hc_tx_ccid and dccps_hc_rx_ccid and set to NULL. Signed-off-by: Mohamed Ghannam Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/dccp/proto.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/dccp/proto.c b/net/dccp/proto.c index b68168fcc06aa198..9d43c1f4027408f3 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -259,25 +259,30 @@ int dccp_disconnect(struct sock *sk, int flags) { struct inet_connection_sock *icsk = inet_csk(sk); struct inet_sock *inet = inet_sk(sk); + struct dccp_sock *dp = dccp_sk(sk); int err = 0; const int old_state = sk->sk_state; if (old_state != DCCP_CLOSED) dccp_set_state(sk, DCCP_CLOSED); /* * This corresponds to the ABORT function of RFC793, sec. 3.8 * TCP uses a RST segment, DCCP a Reset packet with Code 2, "Aborted". */ if (old_state == DCCP_LISTEN) { inet_csk_listen_stop(sk); } else if (dccp_need_reset(old_state)) { dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED); sk->sk_err = ECONNRESET; } else if (old_state == DCCP_REQUESTING) sk->sk_err = ECONNRESET; dccp_clear_xmit_timers(sk); + ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); + ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); + dp->dccps_hc_rx_ccid = NULL; + dp->dccps_hc_tx_ccid = NULL; __skb_queue_purge(&sk->sk_receive_queue); __skb_queue_purge(&sk->sk_write_queue); -- 2.15.1