Описание
In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Serialize compat port-info ioctls
The native sequencer ioctl path serializes handler calls with
client->ioctl_mutex, but the translated port-info compat path invokes the
same handlers through snd_seq_kernel_client_ctl() without taking that
mutex.
This lets concurrent compat CREATE_PORT requests pass the port-count
check before any request reaches the serialized insertion. The computed
integer port index can then exceed the address field range and wrap to an
existing index. Subsequent subscriber teardown can resolve the duplicate
address to the wrong port and access a freed subscriber.
Take ioctl_mutex while dispatching converted port-info requests, matching
the native ioctl path. All translated port-info commands share this
helper, so their accesses to the client port state are serialized as
well.
A flaw was found in the Linux kernel's ALSA (Advanced Linux Sound Architecture) sequencer subsystem. A local user could exploit a race condition caused by missing locking during compatibility ioctl (input/output control) operations. By sending concurrent port creation requests, an attacker can corrupt internal port tracking and trigger a use-after-free condition when resources are released. This flaw may allow a local attacker to cause a system crash, leading to a denial of service (DoS), or potentially achieve privilege escalation.
Отчет
A race condition in the ALSA sequencer compat ioctl path occurs because converted port-info requests call the common handlers without holding client ioctl_mutex. Concurrent compat CREATE_PORT operations can pass the port-count check before insertion, causing the integer port index to exceed the address field range and wrap to an existing port address. Later subscriber teardown can resolve the duplicate address to the wrong port and access a freed subscriber, creating a kernel use-after-free condition. For the CVSS the PR:L is selected because a local user with access to the ALSA sequencer device can invoke the compat ioctls without full administrative privileges. AC:H is selected because reliable triggering requires concurrent requests to hit a race window and a later teardown operation to reach the stale subscriber. The issue is not network reachable. Impact is at least a local denial of service through a kernel crash and in the worst case may include confidentiality and integrity impact or local privilege escalation due to reuse of the freed kernel object.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred |
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Дополнительная информация
Статус:
EPSS
4.7 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize compat port-info ioctls The native sequencer ioctl path serializes handler calls with client->ioctl_mutex, but the translated port-info compat path invokes the same handlers through snd_seq_kernel_client_ctl() without taking that mutex. This lets concurrent compat CREATE_PORT requests pass the port-count check before any request reaches the serialized insertion. The computed integer port index can then exceed the address field range and wrap to an existing index. Subsequent subscriber teardown can resolve the duplicate address to the wrong port and access a freed subscriber. Take ioctl_mutex while dispatching converted port-info requests, matching the native ioctl path. All translated port-info commands share this helper, so their accesses to the client port state are serialized as well.
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize compat port-info ioctls The native sequencer ioctl path serializes handler calls with client->ioctl_mutex, but the translated port-info compat path invokes the same handlers through snd_seq_kernel_client_ctl() without taking that mutex. This lets concurrent compat CREATE_PORT requests pass the port-count check before any request reaches the serialized insertion. The computed integer port index can then exceed the address field range and wrap to an existing index. Subsequent subscriber teardown can resolve the duplicate address to the wrong port and access a freed subscriber. Take ioctl_mutex while dispatching converted port-info requests, matching the native ioctl path. All translated port-info commands share this helper, so their accesses to the client port state are serialized as well.
In the Linux kernel, the following vulnerability has been resolved: A ...
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize compat port-info ioctls The native sequencer ioctl path serializes handler calls with client->ioctl_mutex, but the translated port-info compat path invokes the same handlers through snd_seq_kernel_client_ctl() without taking that mutex. This lets concurrent compat CREATE_PORT requests pass the port-count check before any request reaches the serialized insertion. The computed integer port index can then exceed the address field range and wrap to an existing index. Subsequent subscriber teardown can resolve the duplicate address to the wrong port and access a freed subscriber. Take ioctl_mutex while dispatching converted port-info requests, matching the native ioctl path. All translated port-info commands share this helper, so their accesses to the client port state are serialized as well.
EPSS
4.7 Medium
CVSS3