CVE-2022-50555
In the Linux kernel, the following vulnerability has been resolved:
tipc: fix a null-ptr-deref in tipc_topsrv_accept
syzbot found a crash in tipc_topsrv_accept:
It was caused by srv->listener that might be set to null by tipc_topsrv_stop() in net .exit whereas it's still used in tipc_topsrv_accept() worker.
srv->listener is protected by srv->idr_lock in tipc_topsrv_stop(), so add a check for srv->listener under srv->idr_lock in tipc_topsrv_accept() to avoid the null-ptr-deref. To ensure the lsock is not released during the tipc_topsrv_accept(), move sock_release() after tipc_topsrv_work_stop() where it's waiting until the tipc_topsrv_accept worker to be done.
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Note that sk_callback_lock is used to protect sk->sk_user_data instead of srv->listener, and it should check srv in tipc_topsrv_listener_data_ready() instead. This also ensures that no more tipc_topsrv_accept worker will be started after tipc_conn_close() is called in tipc_topsrv_stop() where it sets sk->sk_user_data to null.
Detalles técnicos trazas, registros y código del informe original
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] Workqueue: tipc_rcv tipc_topsrv_accept RIP: 0010:kernel_accept+0x22d/0x350 net/socket.c:3487 Call Trace: <TASK> tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 11
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-476
Referencias
- https://git.kernel.org/stable/c/24b129aed8730e48f47d852d58d76825ab6f407c
- https://git.kernel.org/stable/c/32a3d4660b34ce49ac0162338ebe362098e2f5df
- https://git.kernel.org/stable/c/7a939503fc32bff4ed60800b73ff7fbb4aea2142
- https://git.kernel.org/stable/c/82cb4e4612c633a9ce320e1773114875604a3cce
- https://git.kernel.org/stable/c/ce69bdac2310152bb70845024d5d704c52aabfc3
- https://git.kernel.org/stable/c/cedb41664e27b2cae7e21487f1bee22dcd84037d
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix a null-ptr-deref in tipc_topsrv_accept\n\nsyzbot found a crash in tipc_topsrv_accept:\n\n KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]\n Workqueue: tipc_rcv tipc_topsrv_accept\n RIP: 0010:kernel_accept+0x22d/0x350 net/socket.c:3487\n Call Trace:\n <TASK>\n tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460\n process_one_work+0x991/0x1610 kernel/workqueue.c:2289\n worker_thread+0x665/0x1080 kernel/workqueue.c:2436\n kthread+0x2e4/0x3a0 kernel/kthread.c:376\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306\n\nIt was caused by srv->listener that might be set to null by\ntipc_topsrv_stop() in net .exit whereas it's still used in\ntipc_topsrv_accept() worker.\n\nsrv->listener is protected by srv->idr_lock in tipc_topsrv_stop(), so add\na check for srv->listener under srv->idr_lock in tipc_topsrv_accept() to\navoid the null-ptr-deref. To ensure the lsock is not released during the\ntipc_topsrv_accept(), move sock_release() after tipc_topsrv_work_stop()\nwhere it's waiting until the tipc_topsrv_accept worker to be done.\n\nNote that sk_callback_lock is used to protect sk->sk_user_data instead of\nsrv->listener, and it should check srv in tipc_topsrv_listener_data_ready()\ninstead. This also ensures that no more tipc_topsrv_accept worker will be\nstarted after tipc_conn_close() is called in tipc_topsrv_stop() where it\nsets sk->sk_user_data to null."
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