"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tun: Fix use-after-free in tun_detach()\n\nsyzbot reported use-after-free in tun_detach() [1]. This causes call\ntrace like below:\n\n==================================================================\nBUG: KASAN: use-after-free in notifier_call_chain+0x1ee/0x200 kernel/notifier.c:75\nRead of size 8 at addr ffff88807324e2a8 by task syz-executor.0/3673\n\nCPU: 0 PID: 3673 Comm: syz-executor.0 Not tainted 6.1.0-rc5-syzkaller-00044-gcc675d22e422 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:284 [inline]\n print_report+0x15e/0x461 mm/kasan/report.c:395\n kasan_report+0xbf/0x1f0 mm/kasan/report.c:495\n notifier_call_chain+0x1ee/0x200 kernel/notifier.c:75\n call_netdevice_notifiers_info+0x86/0x130 net/core/dev.c:1942\n call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]\n call_netdevice_notifiers net/core/dev.c:1997 [inline]\n netdev_wait_allrefs_any net/core/dev.c:10237 [inline]\n netdev_run_todo+0xbc6/0x1100 net/core/dev.c:10351\n tun_detach drivers/net/tun.c:704 [inline]\n tun_chr_close+0xe4/0x190 drivers/net/tun.c:3467\n __fput+0x27c/0xa90 fs/file_table.c:320\n task_work_run+0x16f/0x270 kernel/task_work.c:179\n exit_task_work include/linux/task_work.h:38 [inline]\n do_exit+0xb3d/0x2a30 kernel/exit.c:820\n do_group_exit+0xd4/0x2a0 kernel/exit.c:950\n get_signal+0x21b1/0x2440 kernel/signal.c:2858\n arch_do_signal_or_restart+0x86/0x2300 arch/x86/kernel/signal.c:869\n exit_to_user_mode_loop kernel/entry/common.c:168 [inline]\n exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203\n __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]\n syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296\n do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe cause of the issue is that sock_put() from __tun_detach() drops\nlast reference count for struct net, and then notifier_call_chain()\nfrom netdev_state_change() accesses that struct net.\n\nThis patch fixes the issue by calling sock_put() from tun_detach()\nafter all necessary accesses for the struct net has done."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: tun: Se corrige el use after free en tun_detach() syzbot inform\u00f3 use after free en tun_detach() [1]. Esto provoca un seguimiento de llamadas como el siguiente: ==================================================================== ERROR: KASAN: use after free en notifier_call_chain+0x1ee/0x200 kernel/notifier.c:75 Lectura de tama\u00f1o 8 en la direcci\u00f3n ffff88807324e2a8 por la tarea syz-executor.0/3673 CPU: 0 PID: 3673 Comm: syz-executor.0 No contaminado 6.1.0-rc5-syzkaller-00044-gcc675d22e422 #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 26/10/2022 Seguimiento de llamadas: __dump_stack lib/dump_stack.c:88 [en l\u00ednea] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [en l\u00ednea] print_report+0x15e/0x461 mm/kasan/report.c:395 kasan_report+0xbf/0x1f0 mm/kasan/report.c:495 notifier_call_chain+0x1ee/0x200 kernel/notifier.c:75 call_netdevice_notifiers_info+0x86/0x130 net/core/dev.c:1942 call_netdevice_notifiers_extack net/core/dev.c:1983 [en l\u00ednea] llamar_notificadores_dispositivos_de_red net/core/dev.c:1997 [en l\u00ednea] netdev_wait_allrefs_any net/core/dev.c:10237 [en l\u00ednea] netdev_run_todo+0xbc6/0x1100 net/core/dev.c:10351 tun_detach drivers/net/tun.c:704 [en l\u00ednea] tun_chr_close+0xe4/0x190 drivers/net/tun.c:3467 __fput+0x27c/0xa90 fs/file_table.c:320 tarea_trabajo_ejecutar+0x16f/0x270 kernel/tarea_trabajo.c:179 salir_tarea_trabajo incluir/linux/tarea_trabajo.h:38 [en l\u00ednea] hacer_salir+0xb3d/0x2a30 kernel/exit.c:820 hacer_grupo_salir+0xd4/0x2a0 kernel/exit.c:950 obtener_se\u00f1al+0x21b1/0x2440 kernel/se\u00f1al.c:2858 arch_hacer_se\u00f1al_o_reiniciar+0x86/0x2300 arch/x86/kernel/signal.c:869 bucle_salir_a_modo_usuario kernel/entry/common.c:168 [en l\u00ednea] preparar_salir_a_modo_usuario+0x15f/0x250 kernel/entry/common.c:203 __syscall_salir_a_modo_usuario_trabajo kernel/entry/common.c:285 [en l\u00ednea] syscall_salir_a_modo_usuario+0x1d/0x50 kernel/entry/common.c:296 La causa del problema es que sock_put() de __tun_detach() descarta el \u00faltimo recuento de referencias para struct net y luego notifier_call_chain() de netdev_state_change() accede a ese struct net. Este parche corrige el problema llamando a sock_put() desde tun_detach() despu\u00e9s de que se hayan realizado todos los accesos necesarios para struct net."
