GHSA-WP52-H62R-QWJ4
Vulnerability from github – Published: 2024-12-27 15:31 – Updated: 2025-11-03 21:31In the Linux kernel, the following vulnerability has been resolved:
tipc: Fix use-after-free of kernel socket in cleanup_bearer().
syzkaller reported a use-after-free of UDP kernel socket in cleanup_bearer() without repro. [0][1]
When bearer_disable() calls tipc_udp_disable(), cleanup of the UDP kernel socket is deferred by work calling cleanup_bearer().
tipc_net_stop() waits for such works to finish by checking tipc_net(net)->wq_count. However, the work decrements the count too early before releasing the kernel socket, unblocking cleanup_net() and resulting in use-after-free.
Let's move the decrement after releasing the socket in cleanup_bearer().
[0]: ref_tracker: net notrefcnt@000000009b3d1faf has 1/1 users at sk_alloc+0x438/0x608 inet_create+0x4c8/0xcb0 __sock_create+0x350/0x6b8 sock_create_kern+0x58/0x78 udp_sock_create4+0x68/0x398 udp_sock_create+0x88/0xc8 tipc_udp_enable+0x5e8/0x848 __tipc_nl_bearer_enable+0x84c/0xed8 tipc_nl_bearer_enable+0x38/0x60 genl_family_rcv_msg_doit+0x170/0x248 genl_rcv_msg+0x400/0x5b0 netlink_rcv_skb+0x1dc/0x398 genl_rcv+0x44/0x68 netlink_unicast+0x678/0x8b0 netlink_sendmsg+0x5e4/0x898 ____sys_sendmsg+0x500/0x830
[1]: BUG: KMSAN: use-after-free in udp_hashslot include/net/udp.h:85 [inline] BUG: KMSAN: use-after-free in udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979 udp_hashslot include/net/udp.h:85 [inline] udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979 sk_common_release+0xaf/0x3f0 net/core/sock.c:3820 inet_release+0x1e0/0x260 net/ipv4/af_inet.c:437 inet6_release+0x6f/0xd0 net/ipv6/af_inet6.c:489 __sock_release net/socket.c:658 [inline] sock_release+0xa0/0x210 net/socket.c:686 cleanup_bearer+0x42d/0x4c0 net/tipc/udp_media.c:819 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391 kthread+0x531/0x6b0 kernel/kthread.c:389 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244
Uninit was created at: slab_free_hook mm/slub.c:2269 [inline] slab_free mm/slub.c:4580 [inline] kmem_cache_free+0x207/0xc40 mm/slub.c:4682 net_free net/core/net_namespace.c:454 [inline] cleanup_net+0x16f2/0x19d0 net/core/net_namespace.c:647 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391 kthread+0x531/0x6b0 kernel/kthread.c:389 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244
CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.12.0-rc1-00131-gf66ebf37d69c #7 91723d6f74857f70725e1583cba3cf4adc716cfa Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: events cleanup_bearer
{
"affected": [],
"aliases": [
"CVE-2024-56642"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-12-27T15:15:23Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: Fix use-after-free of kernel socket in cleanup_bearer().\n\nsyzkaller reported a use-after-free of UDP kernel socket\nin cleanup_bearer() without repro. [0][1]\n\nWhen bearer_disable() calls tipc_udp_disable(), cleanup\nof the UDP kernel socket is deferred by work calling\ncleanup_bearer().\n\ntipc_net_stop() waits for such works to finish by checking\ntipc_net(net)-\u003ewq_count. However, the work decrements the\ncount too early before releasing the kernel socket,\nunblocking cleanup_net() and resulting in use-after-free.\n\nLet\u0027s move the decrement after releasing the socket in\ncleanup_bearer().\n\n[0]:\nref_tracker: net notrefcnt@000000009b3d1faf has 1/1 users at\n sk_alloc+0x438/0x608\n inet_create+0x4c8/0xcb0\n __sock_create+0x350/0x6b8\n sock_create_kern+0x58/0x78\n udp_sock_create4+0x68/0x398\n udp_sock_create+0x88/0xc8\n tipc_udp_enable+0x5e8/0x848\n __tipc_nl_bearer_enable+0x84c/0xed8\n tipc_nl_bearer_enable+0x38/0x60\n genl_family_rcv_msg_doit+0x170/0x248\n genl_rcv_msg+0x400/0x5b0\n netlink_rcv_skb+0x1dc/0x398\n genl_rcv+0x44/0x68\n netlink_unicast+0x678/0x8b0\n netlink_sendmsg+0x5e4/0x898\n ____sys_sendmsg+0x500/0x830\n\n[1]:\nBUG: KMSAN: use-after-free in udp_hashslot include/net/udp.h:85 [inline]\nBUG: KMSAN: use-after-free in udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979\n udp_hashslot include/net/udp.h:85 [inline]\n udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979\n sk_common_release+0xaf/0x3f0 net/core/sock.c:3820\n inet_release+0x1e0/0x260 net/ipv4/af_inet.c:437\n inet6_release+0x6f/0xd0 net/ipv6/af_inet6.c:489\n __sock_release net/socket.c:658 [inline]\n sock_release+0xa0/0x210 net/socket.c:686\n cleanup_bearer+0x42d/0x4c0 net/tipc/udp_media.c:819\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310\n worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391\n kthread+0x531/0x6b0 kernel/kthread.c:389\n ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244\n\nUninit was created at:\n slab_free_hook mm/slub.c:2269 [inline]\n slab_free mm/slub.c:4580 [inline]\n kmem_cache_free+0x207/0xc40 mm/slub.c:4682\n net_free net/core/net_namespace.c:454 [inline]\n cleanup_net+0x16f2/0x19d0 net/core/net_namespace.c:647\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310\n worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391\n kthread+0x531/0x6b0 kernel/kthread.c:389\n ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244\n\nCPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.12.0-rc1-00131-gf66ebf37d69c #7 91723d6f74857f70725e1583cba3cf4adc716cfa\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\nWorkqueue: events cleanup_bearer",
"id": "GHSA-wp52-h62r-qwj4",
"modified": "2025-11-03T21:31:56Z",
"published": "2024-12-27T15:31:55Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56642"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4e69457f9dfae67435f3ccf29008768eae860415"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/650ee9a22d7a2de8999fac2d45983597a0c22359"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6a2fa13312e51a621f652d522d7e2df7066330b6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d00d4470bf8c4282617a3a10e76b20a9c7e4cffa"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d2a4894f238551eae178904e7f45af87577074fd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d62d5180c036eeac09f80660edc7a602b369125f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e48b211c4c59062cb6dd6c2c37c51a7cc235a464"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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