"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nax25: Fix refcount imbalance on inbound connections\n\nWhen releasing a socket in ax25_release(), we call netdev_put() to\ndecrease the refcount on the associated ax.25 device. However, the\nexecution path for accepting an incoming connection never calls\nnetdev_hold(). This imbalance leads to refcount errors, and ultimately\nto kernel crashes.\n\nA typical call trace for the above situation will start with one of the\nfollowing errors:\n\n refcount_t: decrement hit 0; leaking memory.\n refcount_t: underflow; use-after-free.\n\nAnd will then have a trace like:\n\n Call Trace:\n <TASK>\n ? show_regs+0x64/0x70\n ? __warn+0x83/0x120\n ? refcount_warn_saturate+0xb2/0x100\n ? report_bug+0x158/0x190\n ? prb_read_valid+0x20/0x30\n ? handle_bug+0x3e/0x70\n ? exc_invalid_op+0x1c/0x70\n ? asm_exc_invalid_op+0x1f/0x30\n ? refcount_warn_saturate+0xb2/0x100\n ? refcount_warn_saturate+0xb2/0x100\n ax25_release+0x2ad/0x360\n __sock_release+0x35/0xa0\n sock_close+0x19/0x20\n [...]\n\nOn reboot (or any attempt to remove the interface), the kernel gets\nstuck in an infinite loop:\n\n unregister_netdevice: waiting for ax0 to become free. Usage count = 0\n\nThis patch corrects these issues by ensuring that we call netdev_hold()\nand ax25_dev_hold() for new connections in ax25_accept(). This makes the\nlogic leading to ax25_accept() match the logic for ax25_bind(): in both\ncases we increment the refcount, which is ultimately decremented in\nax25_release()."
"value":"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: ax25: corrige el desequilibrio de recuento en conexiones entrantes Al liberar un socket en ax25_release(), llamamos a netdev_put() para disminuir el recuento en el dispositivo ax.25 asociado. Sin embargo, la ruta de ejecuci\u00f3n para aceptar una conexi\u00f3n entrante nunca llama a netdev_hold(). Este desequilibrio conduce a errores de recuento y, en \u00faltima instancia, a fallos del kernel. Un seguimiento de llamada t\u00edpico para la situaci\u00f3n anterior comenzar\u00e1 con uno de los siguientes errores: refcount_t: decrement hit 0; p\u00e9rdida de memoria. refcount_t: desbordamiento insuficiente; use-after-free. Y luego tendr\u00e1 un seguimiento como: Call Trace: ? show_regs+0x64/0x70? __advertir+0x83/0x120 ? refcount_warn_saturate+0xb2/0x100? report_bug+0x158/0x190? prb_read_valid+0x20/0x30? handle_bug+0x3e/0x70? exc_invalid_op+0x1c/0x70? asm_exc_invalid_op+0x1f/0x30? refcount_warn_saturate+0xb2/0x100? refcount_warn_saturate+0xb2/0x100 ax25_release+0x2ad/0x360 __sock_release+0x35/0xa0 sock_close+0x19/0x20 [...] Al reiniciar (o cualquier intento de eliminar la interfaz), el kernel se atasca en un bucle infinito: unregister_netdevice: esperando ax0 para quedar libre. Recuento de uso = 0 Este parche corrige estos problemas asegurando que llamemos a netdev_hold() y ax25_dev_hold() para nuevas conexiones en ax25_accept(). Esto hace que la l\u00f3gica que conduce a ax25_accept() coincida con la l\u00f3gica de ax25_bind(): en ambos casos incrementamos el refcount, que finalmente disminuye en ax25_release()."
