{"id":"CVE-2025-21677","summary":"pfcp: Destroy device along with udp socket's netns dismantle.","details":"In the Linux kernel, the following vulnerability has been resolved:\n\npfcp: Destroy device along with udp socket's netns dismantle.\n\npfcp_newlink() links the device to a list in dev_net(dev) instead\nof net, where a udp tunnel socket is created.\n\nEven when net is removed, the device stays alive on dev_net(dev).\nThen, removing net triggers the splat below. [0]\n\nIn this example, pfcp0 is created in ns2, but the udp socket is\ncreated in ns1.\n\n  ip netns add ns1\n  ip netns add ns2\n  ip -n ns1 link add netns ns2 name pfcp0 type pfcp\n  ip netns del ns1\n\nLet's link the device to the socket's netns instead.\n\nNow, pfcp_net_exit() needs another netdev iteration to remove\nall pfcp devices in the netns.\n\npfcp_dev_list is not used under RCU, so the list API is converted\nto the non-RCU variant.\n\npfcp_net_exit() can be converted to .exit_batch_rtnl() in net-next.\n\n[0]:\nref_tracker: net notrefcnt@00000000128b34dc has 1/1 users at\n     sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236)\n     inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252)\n     __sock_create (net/socket.c:1558)\n     udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18)\n     pfcp_create_sock (drivers/net/pfcp.c:168)\n     pfcp_newlink (drivers/net/pfcp.c:182 drivers/net/pfcp.c:197)\n     rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012)\n     rtnetlink_rcv_msg (net/core/rtnetlink.c:6922)\n     netlink_rcv_skb (net/netlink/af_netlink.c:2542)\n     netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347)\n     netlink_sendmsg (net/netlink/af_netlink.c:1891)\n     ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583)\n     ___sys_sendmsg (net/socket.c:2639)\n     __sys_sendmsg (net/socket.c:2669)\n     do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)\n     entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\nWARNING: CPU: 1 PID: 11 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179)\nModules linked in:\nCPU: 1 UID: 0 PID: 11 Comm: kworker/u16:0 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nWorkqueue: netns cleanup_net\nRIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179)\nCode: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 \u003c0f\u003e 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89\nRSP: 0018:ff11000007f3fb60 EFLAGS: 00010286\nRAX: 00000000000020ef RBX: ff1100000d6481e0 RCX: 1ffffffff0e40d82\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c\nRBP: ff1100000d648230 R08: 0000000000000001 R09: fffffbfff0e395af\nR10: 0000000000000001 R11: 0000000000000000 R12: ff1100000d648230\nR13: dead000000000100 R14: ff1100000d648230 R15: dffffc0000000000\nFS:  0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00005620e1363990 CR3: 000000000eeb2002 CR4: 0000000000771ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n ? __warn (kernel/panic.c:748)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? report_bug (lib/bug.c:201 lib/bug.c:219)\n ? handle_bug (arch/x86/kernel/traps.c:285)\n ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))\n ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)\n ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158)\n ? kfree (mm/slub.c:4613 mm/slub.c:4761)\n net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467)\n cleanup_net (net/cor\n---truncated---","modified":"2026-04-02T12:35:20.260433Z","published":"2025-01-31T11:25:38.809Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21677.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1c35a66e2bfea53dea3562b2575ac7fd4c38ee61"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ffc90e9ca61b0f619326a1417ff32efd6cc71ed2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21677.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-21677"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"76c8764ef36a5d37ea2e551bda28ac7f028383ba"},{"fixed":"1c35a66e2bfea53dea3562b2575ac7fd4c38ee61"},{"fixed":"ffc90e9ca61b0f619326a1417ff32efd6cc71ed2"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21677.json"}}],"schema_version":"1.7.5"}