This is a note to let you know that I've just added the patch titled

    mptcp: pm: reuse ID 0 after delete and re-add

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mptcp-pm-reuse-id-0-after-delete-and-re-add.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-73005-greg=kroah.com@vger.kernel.org Wed Sep  4 13:04:05 2024
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Wed,  4 Sep 2024 13:03:08 +0200
Subject: mptcp: pm: reuse ID 0 after delete and re-add
To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>, Mat Martineau <martineau@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Message-ID: <20240904110306.4082410-5-matttbe@kernel.org>

From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>

commit 8b8ed1b429f8fa7ebd5632555e7b047bc0620075 upstream.

When the endpoint used by the initial subflow is removed and re-added
later, the PM has to force the ID 0, it is a special case imposed by the
MPTCP specs.

Note that the endpoint should then need to be re-added reusing the same
ID.

Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/mptcp/pm_netlink.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -600,6 +600,11 @@ static void mptcp_pm_create_subflow_or_s
 
 		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
 		msk->pm.add_addr_signaled++;
+
+		/* Special case for ID0: set the correct ID */
+		if (local.addr.id == msk->mpc_endpoint_id)
+			local.addr.id = 0;
+
 		mptcp_pm_announce_addr(msk, &local.addr, false);
 		mptcp_pm_nl_addr_send_ack(msk);
 
@@ -624,6 +629,11 @@ subflow:
 
 		msk->pm.local_addr_used++;
 		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
+
+		/* Special case for ID0: set the correct ID */
+		if (local.addr.id == msk->mpc_endpoint_id)
+			local.addr.id = 0;
+
 		nr = fill_remote_addresses_vec(msk, &local.addr, fullmesh, addrs);
 		if (nr == 0)
 			continue;


Patches currently in stable-queue which might be from matttbe@kernel.org are

queue-6.1/mptcp-pm-fix-rm_addr-id-for-the-initial-subflow.patch
queue-6.1/selftests-mptcp-join-validate-fullmesh-endp-on-1st-sf.patch
queue-6.1/mptcp-pm-fix-id-0-endp-usage-after-multiple-re-creations.patch
queue-6.1/mptcp-make-pm_remove_addrs_and_subflows-static.patch
queue-6.1/mptcp-pm-avoid-possible-uaf-when-selecting-endp.patch
queue-6.1/mptcp-pm-reuse-id-0-after-delete-and-re-add.patch
queue-6.1/selftests-mptcp-join-check-re-adding-init-endp-with-id.patch
queue-6.1/selftests-mptcp-join-test-for-flush-re-add-endpoints.patch
queue-6.1/selftests-mptcp-add-explicit-test-case-for-remove-re.patch
queue-6.1/selftests-mptcp-add-explicit-test-case-for-remove-readd.patch
queue-6.1/selftests-mptcp-join-check-re-adding-init-endp-with-.patch
queue-6.1/selftests-mptcp-join-check-re-using-id-of-closed-subflow.patch
queue-6.1/mptcp-pm-fullmesh-select-the-right-id-later.patch
queue-6.1/mptcp-pr_debug-add-missing-n-at-the-end.patch
queue-6.1/selftests-mptcp-join-check-re-using-id-of-unused-add.patch
queue-6.1/selftests-mptcp-join-check-re-using-id-of-unused-add_addr.patch