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![Paolo Abeni](/assets/img/avatar_default.png)
In case of early fallback to TCP, subflow_syn_recv_sock() deletes
the subflow context before returning the newly allocated sock to
the caller.
The fastopen path does not cope with the above unconditionally
dereferencing the subflow context.
Fixes: 36b122baf6
("mptcp: add subflow_v(4,6)_send_synack()")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* MPTCP Fast Open Mechanism
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*
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* Copyright (c) 2021-2022, Dmytro SHYTYI
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*/
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#include "protocol.h"
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void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
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struct request_sock *req)
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{
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struct sock *sk, *ssk;
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struct sk_buff *skb;
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struct tcp_sock *tp;
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/* on early fallback the subflow context is deleted by
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* subflow_syn_recv_sock()
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*/
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if (!subflow)
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return;
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ssk = subflow->tcp_sock;
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sk = subflow->conn;
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tp = tcp_sk(ssk);
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subflow->is_mptfo = 1;
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skb = skb_peek(&ssk->sk_receive_queue);
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if (WARN_ON_ONCE(!skb))
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return;
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/* dequeue the skb from sk receive queue */
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__skb_unlink(skb, &ssk->sk_receive_queue);
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skb_ext_reset(skb);
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skb_orphan(skb);
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/* We copy the fastopen data, but that don't belong to the mptcp sequence
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* space, need to offset it in the subflow sequence, see mptcp_subflow_get_map_offset()
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*/
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tp->copied_seq += skb->len;
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subflow->ssn_offset += skb->len;
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/* initialize a dummy sequence number, we will update it at MPC
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* completion, if needed
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*/
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MPTCP_SKB_CB(skb)->map_seq = -skb->len;
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MPTCP_SKB_CB(skb)->end_seq = 0;
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MPTCP_SKB_CB(skb)->offset = 0;
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MPTCP_SKB_CB(skb)->has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
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mptcp_data_lock(sk);
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mptcp_set_owner_r(skb, sk);
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__skb_queue_tail(&sk->sk_receive_queue, skb);
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sk->sk_data_ready(sk);
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mptcp_data_unlock(sk);
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}
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void mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
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const struct mptcp_options_received *mp_opt)
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{
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struct sock *sk = (struct sock *)msk;
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struct sk_buff *skb;
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mptcp_data_lock(sk);
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skb = skb_peek_tail(&sk->sk_receive_queue);
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if (skb) {
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WARN_ON_ONCE(MPTCP_SKB_CB(skb)->end_seq);
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pr_debug("msk %p moving seq %llx -> %llx end_seq %llx -> %llx", sk,
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MPTCP_SKB_CB(skb)->map_seq, MPTCP_SKB_CB(skb)->map_seq + msk->ack_seq,
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MPTCP_SKB_CB(skb)->end_seq, MPTCP_SKB_CB(skb)->end_seq + msk->ack_seq);
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MPTCP_SKB_CB(skb)->map_seq += msk->ack_seq;
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MPTCP_SKB_CB(skb)->end_seq += msk->ack_seq;
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}
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pr_debug("msk=%p ack_seq=%llx", msk, msk->ack_seq);
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mptcp_data_unlock(sk);
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}
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