Описание
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix use-after-free freeing trigger private data
Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing
event_trigger_data") moved the kfree() of event_trigger_data to a kthread
that runs tracepoint_synchronize_unregister() before freeing. That removed
the synchronization the trigger .free callbacks used to get implicitly and
inline from trigger_data_free().
event_hist_trigger_free(), event_hist_trigger_named_free() and
event_enable_trigger_free() free their satellite data (hist_data, cmd_ops,
enable_data) right after trigger_data_free() returns. With the
synchronization now deferred to the kthread, a concurrent tracepoint
handler can still reach that data through the list_del_rcu()'d trigger,
causing a use-after-free.
The histogram teardown must stay synchronous: remove_hist_vars() and
unregister_field_var_hists() have to detach a synthetic event from the
histogram before the trigger-removal write returns, otherwise a following
command races in and the synthetic-event removal fails with -EBUSY, as the
trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait
with the correct barrier - tracepoint_synchronize_unregister(), matching
the free kthread - before freeing.
The enable trigger has no such synchronous requirement, and a blocking
synchronize there would re-serialize the path that commit deliberately
deferred. Give it an optional private_data_free() callback that the free
kthread runs after its grace period, and free enable_data from there.
A flaw was found in the Linux kernel's tracing subsystem. A synchronization issue during the freeing of trigger private data allows a concurrent tracepoint handler to access memory after it has been released. This use-after-free vulnerability could lead to memory corruption.
Отчет
This issue affects kernel tracing event triggers. Bulk GC kthread can free trigger data while still in use. Systems not using trace triggers are not affected.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux for NVIDIA 26 | kernel | Not affected | ||
| Red Hat OpenShift Container Platform 4 | rhcos | Not affected |
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Дополнительная информация
Статус:
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix use-after-free freeing trigger private data Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") moved the kfree() of event_trigger_data to a kthread that runs tracepoint_synchronize_unregister() before freeing. That removed the synchronization the trigger .free callbacks used to get implicitly and inline from trigger_data_free(). event_hist_trigger_free(), event_hist_trigger_named_free() and event_enable_trigger_free() free their satellite data (hist_data, cmd_ops, enable_data) right after trigger_data_free() returns. With the synchronization now deferred to the kthread, a concurrent tracepoint handler can still reach that data through the list_del_rcu()'d trigger, causing a use-after-free. The histogram teardown must stay synchronous: remove_hist_vars() and unregister_field_var_hists() have to detach a synthetic event from the histogram before the trigger-removal ...
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix use-after-free freeing trigger private data Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") moved the kfree() of event_trigger_data to a kthread that runs tracepoint_synchronize_unregister() before freeing. That removed the synchronization the trigger .free callbacks used to get implicitly and inline from trigger_data_free(). event_hist_trigger_free(), event_hist_trigger_named_free() and event_enable_trigger_free() free their satellite data (hist_data, cmd_ops, enable_data) right after trigger_data_free() returns. With the synchronization now deferred to the kthread, a concurrent tracepoint handler can still reach that data through the list_del_rcu()'d trigger, causing a use-after-free. The histogram teardown must stay synchronous: remove_hist_vars() and unregister_field_var_hists() have to detach a synthetic event from the histogram before the trigger-removal
In the Linux kernel, the following vulnerability has been resolved: t ...
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix use-after-free freeing trigger private data Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") moved the kfree() of event_trigger_data to a kthread that runs tracepoint_synchronize_unregister() before freeing. That removed the synchronization the trigger .free callbacks used to get implicitly and inline from trigger_data_free(). event_hist_trigger_free(), event_hist_trigger_named_free() and event_enable_trigger_free() free their satellite data (hist_data, cmd_ops, enable_data) right after trigger_data_free() returns. With the synchronization now deferred to the kthread, a concurrent tracepoint handler can still reach that data through the list_del_rcu()'d trigger, causing a use-after-free. The histogram teardown must stay synchronous: remove_hist_vars() and unregister_field_var_hists() have to detach a synthetic event from the histogram before the trigger-remo...
5.5 Medium
CVSS3