[PATCH AUTOSEL for 4.14 059/100] dccp: CVE-2017-8824: use-after-free in DCCP code

Sasha Levin
2018-01-28T23:05:45Z

From: Mohamed Ghannam <simo.ghannam@gmail.com>

[ Upstream commit 69c64866ce072dea1d1e59a0d61e0f66c0dffb76 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
net/dccp/proto.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index b68168fcc06a..9d43c1f40274 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -259,6 +259,7 @@ 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;

@@ -278,6 +279,10 @@ int dccp_disconnect(struct sock *sk, int flags)
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);
--
2.11.0