2.3 KiB
CVE-2024-46858
Description
In the Linux kernel, the following vulnerability has been resolved:mptcp: pm: Fix uaf in __timer_delete_syncThere are two paths to access mptcp_pm_del_add_timer, result in a racecondition: CPU1 CPU2 ==== ==== net_rx_action napi_poll netlink_sendmsg __napi_poll netlink_unicast process_backlog netlink_unicast_kernel __netif_receive_skb genl_rcv __netif_receive_skb_one_core netlink_rcv_skb NF_HOOK genl_rcv_msg ip_local_deliver_finish genl_family_rcv_msg ip_protocol_deliver_rcu genl_family_rcv_msg_doit tcp_v4_rcv mptcp_pm_nl_flush_addrs_doit tcp_v4_do_rcv mptcp_nl_remove_addrs_list tcp_rcv_established mptcp_pm_remove_addrs_and_subflows tcp_data_queue remove_anno_list_by_saddr mptcp_incoming_options mptcp_pm_del_add_timer mptcp_pm_del_add_timer kfree(entry)In remove_anno_list_by_saddr(running on CPU2), after leaving the criticalzone protected by "pm.lock", the entry will be released, which leads to theoccurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1).Keeping a reference to add_timer inside the lock, and callingsk_stop_timer_sync() with this reference, instead of "entry->add_timer".Move list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock,do not directly access any members of the entry outside the pm lock, whichcan avoid similar "entry->x" uaf.
POC
Reference
No PoCs from references.