| From bippy-7c5fe7eed585 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-21958: Revert "openvswitch: switch to per-action label counting in conntrack" |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| Revert "openvswitch: switch to per-action label counting in conntrack" |
| |
| Currently, ovs_ct_set_labels() is only called for confirmed conntrack |
| entries (ct) within ovs_ct_commit(). However, if the conntrack entry |
| does not have the labels_ext extension, attempting to allocate it in |
| ovs_ct_get_conn_labels() for a confirmed entry triggers a warning in |
| nf_ct_ext_add(): |
| |
| WARN_ON(nf_ct_is_confirmed(ct)); |
| |
| This happens when the conntrack entry is created externally before OVS |
| increments net->ct.labels_used. The issue has become more likely since |
| commit fcb1aa5163b1 ("openvswitch: switch to per-action label counting |
| in conntrack"), which changed to use per-action label counting and |
| increment net->ct.labels_used when a flow with ct action is added. |
| |
| Since there’s no straightforward way to fully resolve this issue at the |
| moment, this reverts the commit to avoid breaking existing use cases. |
| |
| The Linux kernel CVE team has assigned CVE-2025-21958 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.12 with commit fcb1aa5163b1ae4cf2864b688b08927aac51f51e and fixed in 6.12.20 with commit 9e79fdabd52cfce1a021640a81256878a2c516a2 |
| Issue introduced in 6.12 with commit fcb1aa5163b1ae4cf2864b688b08927aac51f51e and fixed in 6.13.8 with commit d91bfc64a4886102746e74d2c6f3a61e9a77fd7d |
| Issue introduced in 6.12 with commit fcb1aa5163b1ae4cf2864b688b08927aac51f51e and fixed in 6.14 with commit 1063ae07383c0ddc5bcce170260c143825846b03 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-21958 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/openvswitch/conntrack.c |
| net/openvswitch/datapath.h |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/9e79fdabd52cfce1a021640a81256878a2c516a2 |
| https://git.kernel.org/stable/c/d91bfc64a4886102746e74d2c6f3a61e9a77fd7d |
| https://git.kernel.org/stable/c/1063ae07383c0ddc5bcce170260c143825846b03 |
