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authorFlorian Westphal <fw@strlen.de>2021-03-04 13:32:12 -0800
committerDavid S. Miller <davem@davemloft.net>2021-03-04 14:30:13 -0800
commitc8fe62f0768cc9378103fc89fb96804645f527c9 (patch)
treea11a21808037ab723d8f6cf32536dff59e6d8a68 /net
parent17aee05dc8822e354f5ad2d68ee39e3ba4b6acf2 (diff)
mptcp: reset 'first' and ack_hint on subflow close
Just like with last_snd, we have to NULL 'first' on subflow close. ack_hint isn't strictly required (its never dereferenced), but better to clear this explicitly as well instead of making it an exception. msk->first is dereferenced unconditionally at accept time, but at that point the ssk is not on the conn_list yet -- this means worker can't see it when iterating the conn_list. Reported-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/mptcp/protocol.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index a58da04bed71..3dcb564b03ad 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2169,6 +2169,12 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
if (ssk == msk->last_snd)
msk->last_snd = NULL;
+ if (ssk == msk->ack_hint)
+ msk->ack_hint = NULL;
+
+ if (ssk == msk->first)
+ msk->first = NULL;
+
if (msk->subflow && ssk == msk->subflow->sk)
mptcp_dispose_initial_subflow(msk);
}
@@ -3297,6 +3303,9 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
/* PM/worker can now acquire the first subflow socket
* lock without racing with listener queue cleanup,
* we can notify it, if needed.
+ *
+ * Even if remote has reset the initial subflow by now
+ * the refcnt is still at least one.
*/
subflow = mptcp_subflow_ctx(msk->first);
list_add(&subflow->node, &msk->conn_list);