fkie_cve-2024-44991
Vulnerability from fkie_nvd
Published
2024-09-04 20:15
Modified
2024-10-09 14:36
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: tcp: prevent concurrent execution of tcp_sk_exit_batch Its possible that two threads call tcp_sk_exit_batch() concurrently, once from the cleanup_net workqueue, once from a task that failed to clone a new netns. In the latter case, error unwinding calls the exit handlers in reverse order for the 'failed' netns. tcp_sk_exit_batch() calls tcp_twsk_purge(). Problem is that since commit b099ce2602d8 ("net: Batch inet_twsk_purge"), this function picks up twsk in any dying netns, not just the one passed in via exit_batch list. This means that the error unwind of setup_net() can "steal" and destroy timewait sockets belonging to the exiting netns. This allows the netns exit worker to proceed to call WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount)); without the expected 1 -> 0 transition, which then splats. At same time, error unwind path that is also running inet_twsk_purge() will splat as well: WARNING: .. at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 ... refcount_dec include/linux/refcount.h:351 [inline] inet_twsk_kill+0x758/0x9c0 net/ipv4/inet_timewait_sock.c:70 inet_twsk_deschedule_put net/ipv4/inet_timewait_sock.c:221 inet_twsk_purge+0x725/0x890 net/ipv4/inet_timewait_sock.c:304 tcp_sk_exit_batch+0x1c/0x170 net/ipv4/tcp_ipv4.c:3522 ops_exit_list+0x128/0x180 net/core/net_namespace.c:178 setup_net+0x714/0xb40 net/core/net_namespace.c:375 copy_net_ns+0x2f0/0x670 net/core/net_namespace.c:508 create_new_namespaces+0x3ea/0xb10 kernel/nsproxy.c:110 ... because refcount_dec() of tw_refcount unexpectedly dropped to 0. This doesn't seem like an actual bug (no tw sockets got lost and I don't see a use-after-free) but as erroneous trigger of debug check. Add a mutex to force strict ordering: the task that calls tcp_twsk_purge() blocks other task from doing final _dec_and_test before mutex-owner has removed all tw sockets of dying netns.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/565d121b69980637f040eb4d84289869cdaabedfPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/99580ae890ec8bd98b21a2a9c6668f8f1555b62ePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e3d9de3742f4d5c47ae35f888d3023a5b54fcd2fPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f6fd2dbf584a4047ba88d1369ff91c9851261ec1Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.11
linux linux_kernel 6.11
linux linux_kernel 6.11
linux linux_kernel 6.11


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                     versionEndExcluding: "6.1.107",
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   cveTags: [],
   descriptions: [
      {
         lang: "en",
         value: "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: prevent concurrent execution of tcp_sk_exit_batch\n\nIts possible that two threads call tcp_sk_exit_batch() concurrently,\nonce from the cleanup_net workqueue, once from a task that failed to clone\na new netns.  In the latter case, error unwinding calls the exit handlers\nin reverse order for the 'failed' netns.\n\ntcp_sk_exit_batch() calls tcp_twsk_purge().\nProblem is that since commit b099ce2602d8 (\"net: Batch inet_twsk_purge\"),\nthis function picks up twsk in any dying netns, not just the one passed\nin via exit_batch list.\n\nThis means that the error unwind of setup_net() can \"steal\" and destroy\ntimewait sockets belonging to the exiting netns.\n\nThis allows the netns exit worker to proceed to call\n\nWARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));\n\nwithout the expected 1 -> 0 transition, which then splats.\n\nAt same time, error unwind path that is also running inet_twsk_purge()\nwill splat as well:\n\nWARNING: .. at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210\n...\n refcount_dec include/linux/refcount.h:351 [inline]\n inet_twsk_kill+0x758/0x9c0 net/ipv4/inet_timewait_sock.c:70\n inet_twsk_deschedule_put net/ipv4/inet_timewait_sock.c:221\n inet_twsk_purge+0x725/0x890 net/ipv4/inet_timewait_sock.c:304\n tcp_sk_exit_batch+0x1c/0x170 net/ipv4/tcp_ipv4.c:3522\n ops_exit_list+0x128/0x180 net/core/net_namespace.c:178\n setup_net+0x714/0xb40 net/core/net_namespace.c:375\n copy_net_ns+0x2f0/0x670 net/core/net_namespace.c:508\n create_new_namespaces+0x3ea/0xb10 kernel/nsproxy.c:110\n\n... because refcount_dec() of tw_refcount unexpectedly dropped to 0.\n\nThis doesn't seem like an actual bug (no tw sockets got lost and I don't\nsee a use-after-free) but as erroneous trigger of debug check.\n\nAdd a mutex to force strict ordering: the task that calls tcp_twsk_purge()\nblocks other task from doing final _dec_and_test before mutex-owner has\nremoved all tw sockets of dying netns.",
      },
      {
         lang: "es",
         value: "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tcp: evitar la ejecución concurrente de tcp_sk_exit_batch Es posible que dos subprocesos llamen a tcp_sk_exit_batch() simultáneamente, una vez desde la cola de trabajo cleanup_net, otra desde una tarea que no pudo clonar una nueva netns. En el último caso, el desenrollado de errores llama a los controladores de salida en orden inverso para las netns \"fallidas\". tcp_sk_exit_batch() llama a tcp_twsk_purge(). El problema es que desde el commit b099ce2602d8 (\"net: Batch inet_twsk_purge\"), esta función recoge twsk en cualquier netn moribundo, no solo en el que se pasa a través de la lista exit_batch. Esto significa que el desenrollado de errores de setup_net() puede \"robar\" y destruir los sockets timewait que pertenecen a las netns que salen. Esto permite que el trabajador de salida netns proceda a llamar a WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount)); sin la transición esperada de 1 -> 0, que luego falla. Al mismo tiempo, la ruta de desenrollado de error que también está ejecutando inet_twsk_purge() también se mostrará: ADVERTENCIA: .. en lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 ... refcount_dec include/linux/refcount.h:351 [en línea] inet_twsk_kill+0x758/0x9c0 net/ipv4/inet_timewait_sock.c:70 inet_twsk_deschedule_put net/ipv4/inet_timewait_sock.c:221 inet_twsk_purge+0x725/0x890 net/ipv4/inet_timewait_sock.c:304 tcp_sk_exit_batch+0x1c/0x170 net/ipv4/tcp_ipv4.c:3522 ops_exit_list+0x128/0x180 net/core/net_namespace.c:178 setup_net+0x714/0xb40 net/core/net_namespace.c:375 copy_net_ns+0x2f0/0x670 net/core/net_namespace.c:508 create_new_namespaces+0x3ea/0xb10 kernel/nsproxy.c:110 ... porque refcount_dec() de tw_refcount cayó inesperadamente a 0. Esto no parece un error real (no se perdieron sockets tw y no veo un use-after-free) sino un disparador erróneo de la comprobación de depuración. Agregue un mutex para forzar un orden estricto: la tarea que llama a tcp_twsk_purge() impide que otra tarea realice _dec_and_test final antes de que el propietario del mutex haya eliminado todos los sockets tw de los netn moribundos.",
      },
   ],
   id: "CVE-2024-44991",
   lastModified: "2024-10-09T14:36:15.790",
   metrics: {
      cvssMetricV31: [
         {
            cvssData: {
               attackComplexity: "LOW",
               attackVector: "LOCAL",
               availabilityImpact: "HIGH",
               baseScore: 5.5,
               baseSeverity: "MEDIUM",
               confidentialityImpact: "NONE",
               integrityImpact: "NONE",
               privilegesRequired: "LOW",
               scope: "UNCHANGED",
               userInteraction: "NONE",
               vectorString: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
               version: "3.1",
            },
            exploitabilityScore: 1.8,
            impactScore: 3.6,
            source: "nvd@nist.gov",
            type: "Primary",
         },
      ],
   },
   published: "2024-09-04T20:15:08.150",
   references: [
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/565d121b69980637f040eb4d84289869cdaabedf",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
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         url: "https://git.kernel.org/stable/c/99580ae890ec8bd98b21a2a9c6668f8f1555b62e",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
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         url: "https://git.kernel.org/stable/c/e3d9de3742f4d5c47ae35f888d3023a5b54fcd2f",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
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         url: "https://git.kernel.org/stable/c/f6fd2dbf584a4047ba88d1369ff91c9851261ec1",
      },
   ],
   sourceIdentifier: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
   vulnStatus: "Analyzed",
   weaknesses: [
      {
         description: [
            {
               lang: "en",
               value: "NVD-CWE-noinfo",
            },
         ],
         source: "nvd@nist.gov",
         type: "Primary",
      },
   ],
}


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