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UBUNTU-CVE-2023-52447

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UBUNTU-CVE-2023-52447

Published: 22 Feb 2024Last Modified: 22 Sept 2026

Upstream:

Aliases:

Summary:

Details: In the Linux kernel, the following vulnerability has been resolved: bpf: Defer the free of inner map when necessary When updating or deleting an inner map in map array or map htab, the map may still be accessed by non-sleepable program or sleepable program. However bpf_map_fd_put_ptr() decreases the ref-counter of the inner map directly through bpf_map_put(), if the ref-counter is the last one (which is true for most cases), the inner map will be freed by ops->map_free() in a kworker. But for now, most .map_free() callbacks don't use synchronize_rcu() or its variants to wait for the elapse of a RCU grace period, so after the invocation of ops->map_free completes, the bpf program which is accessing the inner map may incur use-after-free problem. Fix the free of inner map by invoking bpf_map_free_deferred() after both one RCU grace period and one tasks trace RCU grace period if the inner map has been removed from the outer map before. The deferment is accomplished by using call_rcu() or call_rcu_tasks_trace() when releasing the last ref-counter of bpf map. The newly-added rcu_head field in bpf_map shares the same storage space with work field to reduce the size of bpf_map.

Affected packages

Package

Name: linux-hwe-edge

Purl: pkg:deb/ubuntu/linux-hwe-edge?arch=source&distro=xenial

Affected ranges

Type: ECOSYSTEM

Events:

Introduced- 0

Fixed -None

Affected versions

4.8.0-28.30~16.04.1

4.8.0-30.32~16.04.1

4.8.0-32.34~16.04.1

4.8.0-34.36~16.04.1

Common Vulnerability Scoring System

Attack Vector

Network

Adjacent

Local

Physical

Privileges Required

None

Low

High

User Interaction

None

Required

Scope

Unchanged

Changed

Confidentiality

None

Low

High

Integrity

None

Low

High

Availability

None

Low

High