mptcp: pm: check add_addr_accept_max before accepting new ADD_ADDR

The limits might have changed in between, it is best to check them
before accepting new ADD_ADDR.

Fixes: d0876b2284cf ("mptcp: add the incoming RM_ADDR support")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-10-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 8827815..28a9a37 100644 (file)
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -848,8 +848,8 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
                        /* Note: if the subflow has been closed before, this
                         * add_addr_accepted counter will not be decremented.
                         */
-                       msk->pm.add_addr_accepted--;
-                       WRITE_ONCE(msk->pm.accept_addr, true);
+                       if (--msk->pm.add_addr_accepted < mptcp_pm_get_add_addr_accept_max(msk))
+                               WRITE_ONCE(msk->pm.accept_addr, true);
                }
        }
 }