ghsa-pgc5-vrj2-c9w5
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2024-26654"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-01T09:15:51Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: sh: aica: reorder cleanup operations to avoid UAF bugs\n\nThe dreamcastcard-\u003etimer could schedule the spu_dma_work and the\nspu_dma_work could also arm the dreamcastcard-\u003etimer.\n\nWhen the snd_pcm_substream is closing, the aica_channel will be\ndeallocated. But it could still be dereferenced in the worker\nthread. The reason is that del_timer() will return directly\nregardless of whether the timer handler is running or not and\nthe worker could be rescheduled in the timer handler. As a result,\nthe UAF bug will happen. The racy situation is shown below:\n\n (Thread 1) | (Thread 2)\nsnd_aicapcm_pcm_close() |\n ... | run_spu_dma() //worker\n | mod_timer()\n flush_work() |\n del_timer() | aica_period_elapsed() //timer\n kfree(dreamcastcard-\u003echannel) | schedule_work()\n | run_spu_dma() //worker\n ... | dreamcastcard-\u003echannel-\u003e //USE\n\nIn order to mitigate this bug and other possible corner cases,\ncall mod_timer() conditionally in run_spu_dma(), then implement\nPCM sync_stop op to cancel both the timer and worker. The sync_stop\nop will be called from PCM core appropriately when needed.",
"id": "GHSA-pgc5-vrj2-c9w5",
"modified": "2024-06-25T21:31:12Z",
"published": "2024-04-01T09:30:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26654"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/051e0840ffa8ab25554d6b14b62c9ab9e4901457"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3c907bf56905de7d27b329afaf59c2fb35d17b04"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4206ad65a0ee76920041a755bd3c17c6ba59bba2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/61d4787692c1fccdc268ffa7a891f9c149f50901"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8c990221681688da34295d6d76cc2f5b963e83f5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9d66ae0e7bb78b54e1e0525456c6b54e1d132046"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aa39e6878f61f50892ee2dd9d2176f72020be845"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e955e8a7f38a856fc6534ba4e6bffd4d5cc80ac3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eeb2a2ca0b8de7e1c66afaf719529154e7dc60b2"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
}
],
"schema_version": "1.4.0",
"severity": []
}