CVE-2024-36899

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: gpiolib: cdev: corrige el use after free en lineinfo_changed_notify El problema de use after free ocurre de la siguiente manera: cuando el archivo del dispositivo del chip GPIO se cierra al invocar gpio_chrdev_release(), las líneas vigiladas son liberado por bitmap_free(), pero la cancelación del registro de la cadena de notificador lineinfo_changed_nb falló debido a la espera de escritura de rwsem. Además, una de las líneas del chip GPIO también está en proceso de lanzamiento y contiene el rwsem de lectura de la cadena notificadora. En consecuencia, una condición de ejecución conduce al use after free de watched_lines. Aquí está la pila típica cuando ocurrió el problema: [free] gpio_chrdev_release() --> bitmap_free(cdev->watched_lines) <-- freed --> blocking_notifier_chain_unregister() --> down_write(&nh->rwsem) <-- waiting rwsem --> __down_write_common() --> rwsem_down_write_slowpath() --> schedule_preempt_disabled() --> schedule() [use] st54spi_gpio_dev_release() --> gpio_free() --> gpiod_free() --> gpiod_free_commit() --> gpiod_line_state_notify() --> blocking_notifier_call_chain() --> down_read(&nh->rwsem); <-- held rwsem --> notifier_call_chain() --> lineinfo_changed_notify() --> test_bit(xxxx, cdev->watched_lines) <-- use after free El efecto secundario del problema de use after free es que un GPIO El evento de línea se está generando para el espacio de usuario donde no debería. Sin embargo, dado que chrdev se cerrará, el espacio de usuario no tendrá la oportunidad de leer ese evento de todos modos. Para solucionar el problema, llame a la función bitmap_free() después de cancelar el registro de la cadena de notificadores lineinfo_changed_nb.

In the Linux kernel, the following vulnerability has been resolved: gpiolib: cdev: Fix use after free in lineinfo_changed_notify The use-after-free issue occurs as follows: when the GPIO chip device file is being closed by invoking gpio_chrdev_release(), watched_lines is freed by bitmap_free(), but the unregistration of lineinfo_changed_nb notifier chain failed due to waiting write rwsem. Additionally, one of the GPIO chip's lines is also in the release process and holds the notifier chain's read rwsem. Consequently, a race condition leads to the use-after-free of watched_lines. Here is the typical stack when issue happened: [free] gpio_chrdev_release() --> bitmap_free(cdev->watched_lines) <-- freed --> blocking_notifier_chain_unregister() --> down_write(&nh->rwsem) <-- waiting rwsem --> __down_write_common() --> rwsem_down_write_slowpath() --> schedule_preempt_disabled() --> schedule() [use] st54spi_gpio_dev_release() --> gpio_free() --> gpiod_free() --> gpiod_free_commit() --> gpiod_line_state_notify() --> blocking_notifier_call_chain() --> down_read(&nh->rwsem); <-- held rwsem --> notifier_call_chain() --> lineinfo_changed_notify() --> test_bit(xxxx, cdev->watched_lines) <-- use after free The side effect of the use-after-free issue is that a GPIO line event is being generated for userspace where it shouldn't. However, since the chrdev is being closed, userspace won't have the chance to read that event anyway. To fix the issue, call the bitmap_free() function after the unregistration of lineinfo_changed_nb notifier chain.

This update for the Linux Kernel 5.14.21-150400_24_111 fixes several issues. The following security issues were fixed. Fixed int overflow for stack access size. Sch_cake: do not call cake_destroy from cake_init. Fixed potential UAF in is_valid_oplock_break. Smb: client: fix use-after-free bug in cifs_debug_data_proc_show. Fixed potential UAF in smb2_is_network_name_deleted. Fixed potential UAF in cifs_stats_proc_show. Fixed potential UAF in smb2_is_valid_lease_break. Intermittent nfs mount failures. Fixed potential UAF in cifs_signal_cifsd_for_reconnect. Gpiolib: cdev: Fix use after free in lineinfo_changed_notify. Net: do not leave a dangling sk pointer, when socket creation fails hfsplus: fix uninit-value in copy_name. Fs/9p: only translate RWX permissions for plain 9P2000. Hsr: Prevent use after free in prp_create_tagged_frame. Fixed a general protection fault in i915_perf_open_ioctl. Set gtt bound flag in amdgpu_ttm_gart_bind. Fixed use-after-free bugs caused by sco_sock_timeout. Drm/client: Fully protect modes with dev->mode_config.mutex. Fixed false-positive lockdep splat for spin_lock in __unix_gc. Fixed double free of the ha->vp_map pointer. Fixed underflow in parse_server_interfaces. Fixed Integer Overflow or Wraparound vulnerability in x86 and ARM md, raid, raid5 modules. Fixed use-after-free in ip6_route_mpath_notify. Fixed memory corruption in wifi/iwlwifi. Fixed an out-of-bound bug in ipvlan caused by unset skb->mac_header. Fixed SDMA off-by-one error in _pad_sdma_tx_descs. Fixed a race condition in nfc_llcp_sock_get and nfc_llcp_sock_get_sn. Fixed a race condition in the GSM 0710 tty multiplexor via the GSMIOC_SETCONF ioctl that could lead to local privilege escalation.