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From 80d3e994e0631d9135cadf20a0b5ad483d7e9bbb Mon Sep 17 00:00:00 2001
Message-Id: <80d3e994e0631d9135cadf20a0b5ad483d7e9bbb.1513282811.git.jan.steffens@gmail.com>
In-Reply-To: <c3c1af44db713ac6624e729ea4832d0ce70685e0.1513282811.git.jan.steffens@gmail.com>
References: <c3c1af44db713ac6624e729ea4832d0ce70685e0.1513282811.git.jan.steffens@gmail.com>
From: Mohamed Ghannam <simo.ghannam@gmail.com>
Date: Tue, 5 Dec 2017 20:58:35 +0000
Subject: [PATCH 2/2] 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 <simo.ghannam@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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
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