CVE-2024-26654

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ALSA: sh: aica: reordenar operaciones de limpieza para evitar errores UAF. El dreamcastcard->timer podría programar el spu_dma_work y el spu_dma_work también podría armar el dreamcastcard->timer. Cuando se cierre snd_pcm_substream, se desasignará aica_channel. Pero aún se podría eliminar la referencia en el hilo del trabajador. La razón es que del_timer() regresará directamente independientemente de si el controlador del temporizador se está ejecutando o no y el trabajador podría reprogramarse en el controlador del temporizador. Como resultado, se producirá el error UAF. La situación picante se muestra a continuación: (Thread 1) | (Thread 2) snd_aicapcm_pcm_close() | ... | run_spu_dma() //worker | mod_timer() flush_work() | del_timer() | aica_period_elapsed() //timer kfree(dreamcastcard->channel) | schedule_work() | run_spu_dma() //worker ... | dreamcastcard->channel-> //USE Para mitigar este error y otros posibles casos extremos, llame a mod_timer() condicionalmente en run_spu_dma(), luego implemente la operación PCM sync_stop para cancelar tanto el temporizador como el trabajador. La operación sync_stop se llamará desde el núcleo PCM de forma adecuada cuando sea necesario.

In the Linux kernel, the following vulnerability has been resolved: ALSA: sh: aica: reorder cleanup operations to avoid UAF bugs The dreamcastcard->timer could schedule the spu_dma_work and the spu_dma_work could also arm the dreamcastcard->timer. When the snd_pcm_substream is closing, the aica_channel will be deallocated. But it could still be dereferenced in the worker thread. The reason is that del_timer() will return directly regardless of whether the timer handler is running or not and the worker could be rescheduled in the timer handler. As a result, the UAF bug will happen. The racy situation is shown below: (Thread 1) | (Thread 2) snd_aicapcm_pcm_close() | ... | run_spu_dma() //worker | mod_timer() flush_work() | del_timer() | aica_period_elapsed() //timer kfree(dreamcastcard->channel) | schedule_work() | run_spu_dma() //worker ... | dreamcastcard->channel-> //USE In order to mitigate this bug and other possible corner cases, call mod_timer() conditionally in run_spu_dma(), then implement PCM sync_stop op to cancel both the timer and worker. The sync_stop op will be called from PCM core appropriately when needed.

Ziming Zhang discovered that the DRM driver for VMware Virtual GPU did not properly handle certain error conditions, leading to a NULL pointer dereference. A local attacker could possibly trigger this vulnerability to cause a denial of service. Zheng Wang discovered that the Broadcom FullMAC WLAN driver in the Linux kernel contained a race condition during device removal, leading to a use- after-free vulnerability. A physically proximate attacker could possibly use this to cause a denial of service.