CVE-2023-53020

Summary

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

l2tp: close all race conditions in l2tp_tunnel_register()

The code in l2tp_tunnel_register() is racy in several ways:

  1. It modifies the tunnel socket after publishing it.

  2. It calls setup_udp_tunnel_sock() on an existing socket without locking.

  3. It changes sock lock class on fly, which triggers many syzbot reports.

This patch amends all of them by moving socket initialization code before publishing and under sock lock. As suggested by Jakub, the l2tp lockdep class is not necessary as we can just switch to bh_lock_sock_nested().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux37159ef2c1ae1e696b24b260b241209a19f92c60 < 2d77e5c0ad79004b5ef901895437e9cce6dfcc7eaffected
LinuxLinux37159ef2c1ae1e696b24b260b241209a19f92c60 < 77e8ed776cdb1a24b2aab8fe7c6f1f154235e1ceaffected
LinuxLinux37159ef2c1ae1e696b24b260b241209a19f92c60 < cef0845b6dcfa2f6c2c832e7f9622551456c741daffected
LinuxLinux37159ef2c1ae1e696b24b260b241209a19f92c60 < 0b2c59720e65885a394a017d0cf9cab118914682affected
LinuxLinux3.6affected
LinuxLinux0 < 3.6unaffected
LinuxLinux5.10.166 <= 5.10.*unaffected
LinuxLinux5.15.91 <= 5.15.*unaffected
LinuxLinux6.1.9 <= 6.1.*unaffected
LinuxLinux6.2 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References