| From bippy-1.1.0 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-2024-56751: ipv6: release nexthop on device removal |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ipv6: release nexthop on device removal |
| |
| The CI is hitting some aperiodic hangup at device removal time in the |
| pmtu.sh self-test: |
| |
| unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6 |
| ref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at |
| dst_init+0x84/0x4a0 |
| dst_alloc+0x97/0x150 |
| ip6_dst_alloc+0x23/0x90 |
| ip6_rt_pcpu_alloc+0x1e6/0x520 |
| ip6_pol_route+0x56f/0x840 |
| fib6_rule_lookup+0x334/0x630 |
| ip6_route_output_flags+0x259/0x480 |
| ip6_dst_lookup_tail.constprop.0+0x5c2/0x940 |
| ip6_dst_lookup_flow+0x88/0x190 |
| udp_tunnel6_dst_lookup+0x2a7/0x4c0 |
| vxlan_xmit_one+0xbde/0x4a50 [vxlan] |
| vxlan_xmit+0x9ad/0xf20 [vxlan] |
| dev_hard_start_xmit+0x10e/0x360 |
| __dev_queue_xmit+0xf95/0x18c0 |
| arp_solicit+0x4a2/0xe00 |
| neigh_probe+0xaa/0xf0 |
| |
| While the first suspect is the dst_cache, explicitly tracking the dst |
| owing the last device reference via probes proved such dst is held by |
| the nexthop in the originating fib6_info. |
| |
| Similar to commit f5b51fe804ec ("ipv6: route: purge exception on |
| removal"), we need to explicitly release the originating fib info when |
| disconnecting a to-be-removed device from a live ipv6 dst: move the |
| fib6_info cleanup into ip6_dst_ifdown(). |
| |
| Tested running: |
| |
| ./pmtu.sh cleanup_ipv6_exception |
| |
| in a tight loop for more than 400 iterations with no spat, running an |
| unpatched kernel I observed a splat every ~10 iterations. |
| |
| The Linux kernel CVE team has assigned CVE-2024-56751 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.3 with commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 and fixed in 5.15.181 with commit 77aa9855a878fb43f547ddfbda3127a1e88ad31a |
| Issue introduced in 5.3 with commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 and fixed in 6.1.120 with commit b2f26a27ea3f72f75d18330f76f5d1007c791848 |
| Issue introduced in 5.3 with commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 and fixed in 6.6.64 with commit 43e25adc80269f917d2a195f0d59f74cdd182955 |
| Issue introduced in 5.3 with commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 and fixed in 6.11.11 with commit a3c3f8a4d025acc8c857246ec2b812c59102487a |
| Issue introduced in 5.3 with commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 and fixed in 6.12.2 with commit 0e4c6faaef8a24b762a24ffb767280e263ef8e10 |
| Issue introduced in 5.3 with commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 and fixed in 6.13 with commit eb02688c5c45c3e7af7e71f036a7144f5639cbfe |
| |
| 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-2024-56751 |
| 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/route.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/77aa9855a878fb43f547ddfbda3127a1e88ad31a |
| https://git.kernel.org/stable/c/b2f26a27ea3f72f75d18330f76f5d1007c791848 |
| https://git.kernel.org/stable/c/43e25adc80269f917d2a195f0d59f74cdd182955 |
| https://git.kernel.org/stable/c/a3c3f8a4d025acc8c857246ec2b812c59102487a |
| https://git.kernel.org/stable/c/0e4c6faaef8a24b762a24ffb767280e263ef8e10 |
| https://git.kernel.org/stable/c/eb02688c5c45c3e7af7e71f036a7144f5639cbfe |
