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CVE-2021-3489

Description

The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee ("bpf, ringbuf: Deny reserve of buffers larger than ringbuf") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced via 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") (v5.8-rc1).

POC

Reference

- https://ubuntu.com/security/notices/USN-4949-1

- https://ubuntu.com/security/notices/USN-4950-1

Github

- https://github.com/ARPSyndicate/cvemon

- https://github.com/tanjiti/sec_profile

- https://github.com/yifengyou/ebpf

- https://github.com/yifengyou/learn-ebpf