fkie_cve-2021-47281
Vulnerability from fkie_nvd
Published
2024-05-21 15:15
Modified
2024-12-24 16:30
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Fix race of snd_seq_timer_open()
The timer instance per queue is exclusive, and snd_seq_timer_open()
should have managed the concurrent accesses. It looks as if it's
checking the already existing timer instance at the beginning, but
it's not right, because there is no protection, hence any later
concurrent call of snd_seq_timer_open() may override the timer
instance easily. This may result in UAF, as the leftover timer
instance can keep running while the queue itself gets closed, as
spotted by syzkaller recently.
For avoiding the race, add a proper check at the assignment of
tmr->timeri again, and return -EBUSY if it's been already registered.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 5.13 | |
| linux | linux_kernel | 5.13 | |
| linux | linux_kernel | 5.13 | |
| linux | linux_kernel | 5.13 | |
| linux | linux_kernel | 5.13 |
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Fix race of snd_seq_timer_open()\n\nThe timer instance per queue is exclusive, and snd_seq_timer_open()\nshould have managed the concurrent accesses. It looks as if it\u0027s\nchecking the already existing timer instance at the beginning, but\nit\u0027s not right, because there is no protection, hence any later\nconcurrent call of snd_seq_timer_open() may override the timer\ninstance easily. This may result in UAF, as the leftover timer\ninstance can keep running while the queue itself gets closed, as\nspotted by syzkaller recently.\n\nFor avoiding the race, add a proper check at the assignment of\ntmr-\u003etimeri again, and return -EBUSY if it\u0027s been already registered."
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"value": "En el kernel de Linux se ha resuelto la siguiente vulnerabilidad: ALSA: seq: Fix race of snd_seq_timer_open(). La instancia del temporizador por cola es exclusiva, y snd_seq_timer_open() deber\u00eda haber gestionado los accesos concurrentes. Parece como si estuviera verificando la instancia del temporizador ya existente al principio, pero no es correcto, porque no hay protecci\u00f3n, por lo tanto, cualquier llamada simult\u00e1nea posterior a snd_seq_timer_open() puede anular la instancia del temporizador f\u00e1cilmente. Esto puede resultar en UAF, ya que la instancia del temporizador sobrante puede seguir ejecut\u00e1ndose mientras la cola se cierra, como descubri\u00f3 syzkaller recientemente. Para evitar la ejecuci\u00f3n, agregue una verificaci\u00f3n adecuada en la asignaci\u00f3n de tmr-\u0026gt;timeri nuevamente y devuelva -EBUSY si ya se registr\u00f3."
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"id": "CVE-2021-47281",
"lastModified": "2024-12-24T16:30:22.490",
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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