Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
tracing: Delay module ref count for “enable_event” trigger
Triggers are now delayed from freeing, but can still be triggered until after the RCU grace period has ended. The freeing of the enable_event data is put into the private_data_free() callback, but the put of the module refcount is done immediately.
It is possible that if a module is removed that has an event that would enable (or disable) it is still active, it can read the data of the module after it is removed causing a use-after-free bug.
Move the trace_event_put_ref() that releases the module into the delayed callback so that the module can not be removed until any reference to its events are finished.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0