In the Linux kernel, the following vulnerability has been resolved: ALSA: oss: Fix PCM OSS buffer allocation overflow We've got syzbot reports hitting INT_MAX overflow at vmalloc() allocation that is called from snd_pcm_plug_alloc(). Although we apply the restrictions to input parameters, it's based only on the hw_params of the underlying PCM device. Since the PCM OSS layer allocates a temporary buffer for the data conversion, the size may become unexpectedly large when more channels or higher rates is given; in the reported case, it went over INT_MAX, hence it hits WARN_ON(). This patch is an attempt to avoid such an overflow and an allocation for too large buffers. First off, it adds the limit of 1MB as the upper bound for period bytes. This must be large enough for all use cases, and we really don't want to handle a larger temporary buffer than this size. The size check is performed at two places, where the original period bytes is calculated and where the plugin buffer size is calculated. In addition, the driver uses array_size() and array3_size() for multiplications to catch overflows for the converted period size and buffer bytes.
| Métrique | Valeur | Interprétation |
|---|---|---|
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AV (Vecteur d'Attaque)
Attack Vector
|
Local (L)
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Exploit nécessite un accès local au système |
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AC (Complexité d'Attaque)
Attack Complexity
|
Low (L)
|
Peu de conditions requises pour exploiter |
|
PR (Privilèges Requis)
Privileges Required
|
Low (L)
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Authentifié avec compte utilisateur basique |
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UI (Interaction Utilisateur)
User Interaction
|
None (N)
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Aucune interaction utilisateur nécessaire |
|
S (Périmètre)
Scope
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Unchanged (U)
|
Impact reste dans le périmètre du composant compromis |
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C (Impact Confidentialité)
Confidentiality Impact
|
High (H)
|
Divulgation totale d'informations |
|
I (Impact Intégrité)
Integrity Impact
|
High (H)
|
Modification totale des données possible |
|
A (Impact Disponibilité)
Availability Impact
|
High (H)
|
Interruption totale du service possible |
ALSA: oss: Fix PCM OSS buffer allocation overflow