| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-22021: netfilter: socket: Lookup orig tuple for IPv6 SNAT |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfilter: socket: Lookup orig tuple for IPv6 SNAT |
| |
| nf_sk_lookup_slow_v4 does the conntrack lookup for IPv4 packets to |
| restore the original 5-tuple in case of SNAT, to be able to find the |
| right socket (if any). Then socket_match() can correctly check whether |
| the socket was transparent. |
| |
| However, the IPv6 counterpart (nf_sk_lookup_slow_v6) lacks this |
| conntrack lookup, making xt_socket fail to match on the socket when the |
| packet was SNATed. Add the same logic to nf_sk_lookup_slow_v6. |
| |
| IPv6 SNAT is used in Kubernetes clusters for pod-to-world packets, as |
| pods' addresses are in the fd00::/8 ULA subnet and need to be replaced |
| with the node's external address. Cilium leverages Envoy to enforce L7 |
| policies, and Envoy uses transparent sockets. Cilium inserts an iptables |
| prerouting rule that matches on `-m socket --transparent` and redirects |
| the packets to localhost, but it fails to match SNATed IPv6 packets due |
| to that missing conntrack lookup. |
| |
| The Linux kernel CVE team has assigned CVE-2025-22021 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 5.4.292 with commit 6488b96a79a26e19100ad872622f04e93b638d7f |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 5.10.236 with commit 58ab63d3ded2ca6141357a2b24eee8453d0f871d |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 5.15.180 with commit 1ca2169cc19dca893c7aae6af122852097435d16 |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 6.1.133 with commit 1ec43100f7123010730b7ddfc3d5c2eac19e70e7 |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 6.6.86 with commit 5251041573850e5020cd447374e23010be698898 |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 6.12.22 with commit 2bb139e483f8cbe488d19d8c1135ac3615e2668c |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 6.13.10 with commit 41904cbb343d115931d6bf79aa2c815cac4ef72b |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 6.14.1 with commit 221c27259324ec1404f028d4f5a0f2ae7f63ee23 |
| Issue introduced in 3.13 with commit eb31628e37a0a4e01fffd79dcc7f815d2357f53a and fixed in 6.15 with commit 932b32ffd7604fb00b5c57e239a3cc4d901ccf6e |
| |
| 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-2025-22021 |
| 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/ipv6/netfilter/nf_socket_ipv6.c |
| |
| |
| 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/6488b96a79a26e19100ad872622f04e93b638d7f |
| https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d |
| https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16 |
| https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7 |
| https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898 |
| https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c |
| https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b |
| https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23 |
| https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e |
