cve-2021-47408
Vulnerability from cvelistv5
Published
2024-05-21 15:04
Modified
2024-11-04 12:05
Severity ?
EPSS score ?
Summary
netfilter: conntrack: serialize hash resizes and cleanups
References
Impacted products
{
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"baseScore": 4.7,
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"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
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"id": "CVE-2021-47408",
"options": [
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"timestamp": "2024-05-29T18:07:55.386862Z",
"version": "2.0.3"
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"product": "Linux",
"programFiles": [
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: conntrack: serialize hash resizes and cleanups\n\nSyzbot was able to trigger the following warning [1]\n\nNo repro found by syzbot yet but I was able to trigger similar issue\nby having 2 scripts running in parallel, changing conntrack hash sizes,\nand:\n\nfor j in `seq 1 1000` ; do unshare -n /bin/true \u003e/dev/null ; done\n\nIt would take more than 5 minutes for net_namespace structures\nto be cleaned up.\n\nThis is because nf_ct_iterate_cleanup() has to restart everytime\na resize happened.\n\nBy adding a mutex, we can serialize hash resizes and cleanups\nand also make get_next_corpse() faster by skipping over empty\nbuckets.\n\nEven without resizes in the picture, this patch considerably\nspeeds up network namespace dismantles.\n\n[1]\nINFO: task syz-executor.0:8312 can\u0027t die for more than 144 seconds.\ntask:syz-executor.0 state:R running task stack:25672 pid: 8312 ppid: 6573 flags:0x00004006\nCall Trace:\n context_switch kernel/sched/core.c:4955 [inline]\n __schedule+0x940/0x26f0 kernel/sched/core.c:6236\n preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6408\n preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35\n __local_bh_enable_ip+0x109/0x120 kernel/softirq.c:390\n local_bh_enable include/linux/bottom_half.h:32 [inline]\n get_next_corpse net/netfilter/nf_conntrack_core.c:2252 [inline]\n nf_ct_iterate_cleanup+0x15a/0x450 net/netfilter/nf_conntrack_core.c:2275\n nf_conntrack_cleanup_net_list+0x14c/0x4f0 net/netfilter/nf_conntrack_core.c:2469\n ops_exit_list+0x10d/0x160 net/core/net_namespace.c:171\n setup_net+0x639/0xa30 net/core/net_namespace.c:349\n copy_net_ns+0x319/0x760 net/core/net_namespace.c:470\n create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110\n unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226\n ksys_unshare+0x445/0x920 kernel/fork.c:3128\n __do_sys_unshare kernel/fork.c:3202 [inline]\n __se_sys_unshare kernel/fork.c:3200 [inline]\n __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3200\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\nRIP: 0033:0x7f63da68e739\nRSP: 002b:00007f63d7c05188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110\nRAX: ffffffffffffffda RBX: 00007f63da792f80 RCX: 00007f63da68e739\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000\nRBP: 00007f63da6e8cc4 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 00007f63da792f80\nR13: 00007fff50b75d3f R14: 00007f63d7c05300 R15: 0000000000022000\n\nShowing all locks held in the system:\n1 lock held by khungtaskd/27:\n #0: ffffffff8b980020 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446\n2 locks held by kworker/u4:2/153:\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2268\n #1: ffffc9000140fdb0 ((kfence_timer).work){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2272\n1 lock held by systemd-udevd/2970:\n1 lock held by in:imklog/6258:\n #0: ffff88807f970ff0 (\u0026f-\u003ef_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990\n3 locks held by kworker/1:6/8158:\n1 lock held by syz-executor.0/8312:\n2 locks held by kworker/u4:13/9320:\n1 lock held by\n---truncated---"
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"title": "netfilter: conntrack: serialize hash resizes and cleanups",
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"cveId": "CVE-2021-47408",
"datePublished": "2024-05-21T15:04:00.651Z",
"dateReserved": "2024-05-21T14:58:30.817Z",
"dateUpdated": "2024-11-04T12:05:21.262Z",
"state": "PUBLISHED"
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"nvd": "{\"cve\":{\"id\":\"CVE-2021-47408\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-05-21T15:15:26.337\",\"lastModified\":\"2024-11-01T15:35:03.077\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnetfilter: conntrack: serialize hash resizes and cleanups\\n\\nSyzbot was able to trigger the following warning [1]\\n\\nNo repro found by syzbot yet but I was able to trigger similar issue\\nby having 2 scripts running in parallel, changing conntrack hash sizes,\\nand:\\n\\nfor j in `seq 1 1000` ; do unshare -n /bin/true \u003e/dev/null ; done\\n\\nIt would take more than 5 minutes for net_namespace structures\\nto be cleaned up.\\n\\nThis is because nf_ct_iterate_cleanup() has to restart everytime\\na resize happened.\\n\\nBy adding a mutex, we can serialize hash resizes and cleanups\\nand also make get_next_corpse() faster by skipping over empty\\nbuckets.\\n\\nEven without resizes in the picture, this patch considerably\\nspeeds up network namespace dismantles.\\n\\n[1]\\nINFO: task syz-executor.0:8312 can\u0027t die for more than 144 seconds.\\ntask:syz-executor.0 state:R running task stack:25672 pid: 8312 ppid: 6573 flags:0x00004006\\nCall Trace:\\n context_switch kernel/sched/core.c:4955 [inline]\\n __schedule+0x940/0x26f0 kernel/sched/core.c:6236\\n preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6408\\n preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35\\n __local_bh_enable_ip+0x109/0x120 kernel/softirq.c:390\\n local_bh_enable include/linux/bottom_half.h:32 [inline]\\n get_next_corpse net/netfilter/nf_conntrack_core.c:2252 [inline]\\n nf_ct_iterate_cleanup+0x15a/0x450 net/netfilter/nf_conntrack_core.c:2275\\n nf_conntrack_cleanup_net_list+0x14c/0x4f0 net/netfilter/nf_conntrack_core.c:2469\\n ops_exit_list+0x10d/0x160 net/core/net_namespace.c:171\\n setup_net+0x639/0xa30 net/core/net_namespace.c:349\\n copy_net_ns+0x319/0x760 net/core/net_namespace.c:470\\n create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110\\n unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226\\n ksys_unshare+0x445/0x920 kernel/fork.c:3128\\n __do_sys_unshare kernel/fork.c:3202 [inline]\\n __se_sys_unshare kernel/fork.c:3200 [inline]\\n __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3200\\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\\n entry_SYSCALL_64_after_hwframe+0x44/0xae\\nRIP: 0033:0x7f63da68e739\\nRSP: 002b:00007f63d7c05188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110\\nRAX: ffffffffffffffda RBX: 00007f63da792f80 RCX: 00007f63da68e739\\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000\\nRBP: 00007f63da6e8cc4 R08: 0000000000000000 R09: 0000000000000000\\nR10: 0000000000000000 R11: 0000000000000246 R12: 00007f63da792f80\\nR13: 00007fff50b75d3f R14: 00007f63d7c05300 R15: 0000000000022000\\n\\nShowing all locks held in the system:\\n1 lock held by khungtaskd/27:\\n #0: ffffffff8b980020 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446\\n2 locks held by kworker/u4:2/153:\\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]\\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]\\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]\\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]\\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]\\n #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2268\\n #1: ffffc9000140fdb0 ((kfence_timer).work){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2272\\n1 lock held by systemd-udevd/2970:\\n1 lock held by in:imklog/6258:\\n #0: ffff88807f970ff0 (\u0026f-\u003ef_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990\\n3 locks held by kworker/1:6/8158:\\n1 lock held by syz-executor.0/8312:\\n2 locks held by kworker/u4:13/9320:\\n1 lock held by\\n---truncated---\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: netfilter: conntrack: serializar cambios de tama\u00f1o y limpiezas de hash. Syzbot pudo activar la siguiente advertencia [1] Syzbot a\u00fan no encontr\u00f3 ninguna reproducci\u00f3n, pero pude desencadenar un problema similar al tener 2 scripts ejecut\u00e1ndose en paralelo, cambiando los tama\u00f1os de hash de conntrack y: para j en `seq 1 1000`; dejar de compartir -n /bin/true \u0026gt;/dev/null ; done Se necesitar\u00edan m\u00e1s de 5 minutos para limpiar las estructuras net_namespace. Esto se debe a que nf_ct_iterate_cleanup() tiene que reiniciarse cada vez que ocurre un cambio de tama\u00f1o. Al agregar un mutex, podemos serializar los cambios de tama\u00f1o y las limpiezas de hash y tambi\u00e9n hacer que get_next_corpse() sea m\u00e1s r\u00e1pido omitiendo los dep\u00f3sitos vac\u00edos. Incluso sin cambios de tama\u00f1o en la imagen, este parche acelera considerablemente el desmantelamiento del espacio de nombres de la red. [1] INFORMACI\u00d3N: la tarea syz-executor.0:8312 no puede morir durante m\u00e1s de 144 segundos. tarea:syz-executor.0 estado:R ejecutando pila de tareas:25672 pid: 8312 ppid: 6573 banderas:0x00004006 Seguimiento de llamadas: context_switch kernel/sched/core.c:4955 [en l\u00ednea] __schedule+0x940/0x26f0 kernel/sched/core .c:6236 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6408 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __local_bh_enable_ip+0x109/0x120 kernel/softirq.c:390 local_bh_enable include/ Linux /bottom_half.h:32 [en l\u00ednea] get_next_corpse net/netfilter/nf_conntrack_core.c:2252 [en l\u00ednea] nf_ct_iterate_cleanup+0x15a/0x450 net/netfilter/nf_conntrack_core.c:2275 nf_conntrack_cleanup_net_list+0x14c/0x4f0 net/netfilter/ nf_conntrack_core.c:2469 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:171 setup_net+0x639/0xa30 net/core/net_namespace.c:349 copy_net_ns+0x319/0x760 net/core/net_namespace.c:470 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy .c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3128 __do_sys_unshare kernel/fork.c:3202 [en l\u00ednea] __se_sys_unshare kernel/fork.c:3200 [en l\u00ednea] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3200 do_syscall_x64 arch/x86/entry/common.c:50 [en l\u00ednea] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 Entry_SYSCALL_64_after_hwframe+0x44/0xae : 0033:0x7f63da68e739 RSP: 002b:00007f63d7c05188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f63da792f80 RCX: 63da68e739 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 00007f63da6e8cc4 R08: 0000000000000000 R09: 000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f63da792f80 R13: 00007fff50b75d3f R14: 00007f63d7c05300 R15: 0000000000022000 Mostrando todos los bloqueos retenidos en el sistema: 1 bloqueo retenido por khungtaskd/27: #0: ffffffff8b980020 (rcu_read_lock){....}-{1:2}, : debug_show_all_locks+0x53 /0x260 kernel/locking/lockdep.c:6446 2 bloqueos retenidos por kworker/u4:2/153: #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, en: arch_atomic64_set arch /x86/include/asm/atomic64_64.h:34 [en l\u00ednea] #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, en: arch_atomic_long_set include/linux/atomic/atomic-long .h:41 [en l\u00ednea] #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, en: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [en l\u00ednea] # 0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, en: set_work_data kernel/workqueue.c:634 [en l\u00ednea] #0: ffff888010c69138 ((wq_completion)events_unbound){+.+. }-{0:0}, en: set_work_pool_and_clear_pending kernel/workqueue.c:661 [en l\u00ednea] #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, en: Process_one_work+0x896/ 0x1690 kernel/workqueue.c:2268 #1: ffffc9000140fdb0 ((kfence_timer).work){+.+.}-{0:0}, en: Process_one_work+0x8ca/0x1690 kernel/workqueue.c:2272 1 bloqueo retenido por systemd-udevd/2970: 1 bloqueo retenido por in:imklog/6258: #0: ffff88807f970ff0 (\u0026amp;f-\u0026gt;f_pos_lock){+.+.}-{3:3}, en: __fdget_pos+0xe9/0x100 ---truncado---\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\",\"baseScore\":4.7,\"baseSeverity\":\"MEDIUM\"},\"exploitabilityScore\":1.0,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/7ea6f5848281182ce0cff6cafdcf3fbdeb8ca7e1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e2d192301a0df8160d1555b66ae8611e8050e424\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e9edc188fc76499b0b9bd60364084037f6d03773\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}