CVE-2024-26654

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.

• linux linux kernel (>= 2.6.23 < 4.19.312) • linux linux kernel (>= 4.20 < 5.4.274) • linux linux kernel (>= 5.5 < 5.10.215) • linux linux kernel (>= 5.11 < 5.15.154) • linux linux kernel (>= 5.16 < 6.1.84) • linux linux kernel (>= 6.2 < 6.6.24) • linux linux kernel (>= 6.7 < 6.7.12) • linux linux kernel (>= 6.8 < 6.8.3) • linux linux kernel 6.9 • debian debian linux 10.0