"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: Fix uaf in __timer_delete_sync\n\nThere are two paths to access mptcp_pm_del_add_timer, result in a race\ncondition:\n\n CPU1\t\t\t\tCPU2\n ==== ====\n net_rx_action\n napi_poll netlink_sendmsg\n __napi_poll netlink_unicast\n process_backlog netlink_unicast_kernel\n __netif_receive_skb genl_rcv\n __netif_receive_skb_one_core netlink_rcv_skb\n NF_HOOK genl_rcv_msg\n ip_local_deliver_finish genl_family_rcv_msg\n ip_protocol_deliver_rcu genl_family_rcv_msg_doit\n tcp_v4_rcv mptcp_pm_nl_flush_addrs_doit\n tcp_v4_do_rcv mptcp_nl_remove_addrs_list\n tcp_rcv_established mptcp_pm_remove_addrs_and_subflows\n tcp_data_queue remove_anno_list_by_saddr\n mptcp_incoming_options mptcp_pm_del_add_timer\n mptcp_pm_del_add_timer kfree(entry)\n\nIn remove_anno_list_by_saddr(running on CPU2), after leaving the critical\nzone protected by \"pm.lock\", the entry will be released, which leads to the\noccurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1).\n\nKeeping a reference to add_timer inside the lock, and calling\nsk_stop_timer_sync() with this reference, instead of \"entry->add_timer\".\n\nMove list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock,\ndo not directly access any members of the entry outside the pm lock, which\ncan avoid similar \"entry->x\" uaf."
