UBUNTU-CVE-2021-3489

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UBUNTU-CVE-2021-3489

Summary:

Details: 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).

References: https://ubuntu.com/security/CVE-2021-3489, https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6ea, https://www.openwall.com/lists/oss-security/2021/05/11/10, https://ubuntu.com/security/notices/USN-4948-1, https://ubuntu.com/security/notices/USN-4949-1, https://ubuntu.com/security/notices/USN-4950-1, https://www.cve.org/CVERecord?id=CVE-2021-3489