"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/iucv: fix use after free in iucv_sock_close()\n\niucv_sever_path() is called from process context and from bh context.\niucv->path is used as indicator whether somebody else is taking care of\nsevering the path (or it is already removed / never existed).\nThis needs to be done with atomic compare and swap, otherwise there is a\nsmall window where iucv_sock_close() will try to work with a path that has\nalready been severed and freed by iucv_callback_connrej() called by\niucv_tasklet_fn().\n\nExample:\n[452744.123844] Call Trace:\n[452744.123845] ([<0000001e87f03880>] 0x1e87f03880)\n[452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x138\n[452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv]\n[452744.124336] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv]\n[452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv]\n[452744.124345] [<00000000d574794e>] __sock_release+0x5e/0xe8\n[452744.124815] [<00000000d5747a0c>] sock_close+0x34/0x48\n[452744.124820] [<00000000d5421642>] __fput+0xba/0x268\n[452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0\n[452744.124832] [<00000000d5145710>] do_notify_resume+0x88/0x90\n[452744.124841] [<00000000d5978096>] system_call+0xe2/0x2c8\n[452744.125319] Last Breaking-Event-Address:\n[452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138\n[452744.125324]\n[452744.125325] Kernel panic - not syncing: Fatal exception in interrupt\n\nNote that bh_lock_sock() is not serializing the tasklet context against\nprocess context, because the check for sock_owned_by_user() and\ncorresponding handling is missing.\n\nIdeas for a future clean-up patch:\nA) Correct usage of bh_lock_sock() in tasklet context, as described in\nRe-enqueue, if needed. This may require adding return values to the\ntasklet functions and thus changes to all users of iucv.\n\nB) Change iucv tasklet into worker and use only lock_sock() in af_iucv."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/iucv: corrige el use after free en iucv_sock_close() iucv_sever_path() se llama desde el contexto del proceso y desde el contexto bh. iucv->path se utiliza como indicador de si alguien m\u00e1s se est\u00e1 encargando de cortar la ruta (o si ya se elimin\u00f3 o nunca existi\u00f3). Esto debe hacerse con comparaci\u00f3n e intercambio at\u00f3mico; de lo contrario, hay una peque\u00f1a ventana donde iucv_sock_close() intentar\u00e1 trabajar con una ruta que ya ha sido cortada y liberada por iucv_callback_connrej() llamada por iucv_tasklet_fn(). Ejemplo: [452744.123844] Seguimiento de llamadas: [452744.123845] ([<0000001e87f03880>] 0x1e87f03880) [452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x13 8 [452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv] [452744.124336 ] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv] [452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv] [452744.124345] 000000d574794e>] __sock_release+0x5e/0xe8 [452744.124815] [<00000000d5747a0c> ] sock_close+0x34/0x48 [452744.124820] [<00000000d5421642>] __fput+0xba/0x268 [452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0 [452744.1 24832] [<00000000d5145710>] do_notify_resume+0x88/0x90 [452744.124841] [< 00000000d5978096>] system_call+0xe2/0x2c8 [452744.125319] \u00daltima direcci\u00f3n del evento de \u00faltima hora: [452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138 [452744.125 324] [452744.125325] P\u00e1nico del kernel: no se sincroniza: excepci\u00f3n fatal en la interrupci\u00f3n. Tenga en cuenta que bh_lock_sock () no serializa el contexto del tasklet con respecto al contexto del proceso, porque falta la verificaci\u00f3n de sock_owned_by_user() y el manejo correspondiente. Ideas para un futuro parche de limpieza: A) Uso correcto de bh_lock_sock() en el contexto del tasklet, como se describe en Volver a poner en cola, si es necesario. Esto puede requerir agregar valores de retorno a las funciones del tasklet y, por lo tanto, cambios para todos los usuarios de iucv. B) Cambie el tasklet iucv a trabajador y use solo lock_sock() en af_iucv."