Use After Free Affecting kernel-core package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Use After Free vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-CENTOS9-KERNELCORE-8112659
  • published28 Sept 2024
  • disclosed27 Sept 2024

Introduced: 27 Sep 2024

CVE-2024-46858  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

There is no fixed version for Centos:9 kernel-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by Centos. See How to fix? for Centos:9 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

mptcp: pm: Fix uaf in __timer_delete_sync

There are two paths to access mptcp_pm_del_add_timer, result in a race condition:

 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 critical zone protected by "pm.lock", the entry will be released, which leads to the occurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1).

Keeping a reference to add_timer inside the lock, and calling sk_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, which can avoid similar "entry->x" uaf.

CVSS Scores

version 3.1