Описание
In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Clear variable event pointer on read
snd_seq_read() copies a queued variable-length event header to userspace
before expanding the payload. Queued variable-length events use
SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first
extension cell.
The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the
copy, but it leaves data.ext.ptr untouched. A userspace sequencer client
can therefore write a direct variable event to itself and read back the
extension-cell kernel address from the returned header.
Clear the temporary header pointer before copy_to_user(). The original
queued event remains unchanged and is still passed to
snd_seq_expand_var_event(), so payload expansion keeps using the
internal chain.
A flaw was found in the ALSA (Advanced Linux Sound Architecture) sequencer component of the Linux kernel. A local attacker, by writing a direct variable event to itself, can read back a kernel memory address from the returned event header. This information disclosure could potentially be used to bypass Address Space Layout Randomization (ASLR) and facilitate further attacks.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred |
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Дополнительная информация
Статус:
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Clear variable event pointer on read snd_seq_read() copies a queued variable-length event header to userspace before expanding the payload. Queued variable-length events use SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first extension cell. The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the copy, but it leaves data.ext.ptr untouched. A userspace sequencer client can therefore write a direct variable event to itself and read back the extension-cell kernel address from the returned header. Clear the temporary header pointer before copy_to_user(). The original queued event remains unchanged and is still passed to snd_seq_expand_var_event(), so payload expansion keeps using the internal chain.
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Clear variable event pointer on read snd_seq_read() copies a queued variable-length event header to userspace before expanding the payload. Queued variable-length events use SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first extension cell. The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the copy, but it leaves data.ext.ptr untouched. A userspace sequencer client can therefore write a direct variable event to itself and read back the extension-cell kernel address from the returned header. Clear the temporary header pointer before copy_to_user(). The original queued event remains unchanged and is still passed to snd_seq_expand_var_event(), so payload expansion keeps using the internal chain.
In the Linux kernel, the following vulnerability has been resolved: A ...
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Clear variable event pointer on read snd_seq_read() copies a queued variable-length event header to userspace before expanding the payload. Queued variable-length events use SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first extension cell. The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the copy, but it leaves data.ext.ptr untouched. A userspace sequencer client can therefore write a direct variable event to itself and read back the extension-cell kernel address from the returned header. Clear the temporary header pointer before copy_to_user(). The original queued event remains unchanged and is still passed to snd_seq_expand_var_event(), so payload expansion keeps using the internal chain.
5.5 Medium
CVSS3