Huawei EulerOS: CVE-2024-49940: kernel security update

Huawei EulerOS: CVE-2024-49940: kernel security update

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

10/21/2024

Created

02/12/2025

Added

02/11/2025

Modified

02/11/2025

Description

In the Linux kernel, the following vulnerability has been resolved: l2tp: prevent possible tunnel refcount underflow When a session is created, it sets a backpointer to its tunnel. When the session refcount drops to 0, l2tp_session_free drops the tunnel refcount if session->tunnel is non-NULL. However, session->tunnel is set in l2tp_session_create, before the tunnel refcount is incremented by l2tp_session_register, which leaves a small window where session->tunnel is non-NULL when the tunnel refcount hasn't been bumped. Moving the assignment to l2tp_session_register is trivial but l2tp_session_create calls l2tp_session_set_header_len which uses session->tunnel to get the tunnel's encap. Add an encap arg to l2tp_session_set_header_len to avoid using session->tunnel. If l2tpv3 sessions have colliding IDs, it is possible for l2tp_v3_session_get to race with l2tp_session_register and fetch a session which doesn't yet have session->tunnel set. Add a check for this case.

Solution(s)

• huawei-euleros-2_0_sp11-upgrade-bpftool
• huawei-euleros-2_0_sp11-upgrade-kernel
• huawei-euleros-2_0_sp11-upgrade-kernel-abi-stablelists
• huawei-euleros-2_0_sp11-upgrade-kernel-tools
• huawei-euleros-2_0_sp11-upgrade-kernel-tools-libs
• huawei-euleros-2_0_sp11-upgrade-python3-perf

References

• https://attackerkb.com/topics/cve-2024-49940
• CVE - 2024-49940
• EulerOS-SA-2025-1159