CVE-2020-8835 log

Source
Severity High
Remote No
Type Privilege escalation
Description
An out-of-bounds access flaw was found in the Linux kernel’s implementation of the eBPF code verifier, where an incorrect register bounds calculation while checking 32-bit instructions in an eBPF program occurs. This flaw allows an unprivileged user or process to execute eBPF programs to crash the kernel, resulting in a denial of service or potentially gaining root privileges on the system.
Group Package Affected Fixed Severity Status Ticket
AVG-1122 linux 5.5.13.arch1-1 5.5.13.arch2-1 High Fixed
AVG-1121 linux-lts 5.4.28-1 5.4.28-2 High Fixed
AVG-1120 linux-hardened 5.5.13.a-1 5.5.13.b-1 High Fixed
Date Advisory Group Package Severity Description
01 Apr 2020 ASA-202004-4 AVG-1122 linux High privilege escalation
01 Apr 2020 ASA-202004-3 AVG-1121 linux-lts High privilege escalation
01 Apr 2020 ASA-202004-2 AVG-1120 linux-hardened High privilege escalation
References
https://www.thezdi.com/blog/2020/3/19/pwn2own-2020-day-one-results
https://lore.kernel.org/bpf/20200330160324.15259-1-daniel@iogearbox.net/T/
https://www.openwall.com/lists/oss-security/2020/03/30/3
Notes
Workaround:
# sysctl -w kernel.unprivileged_bpf_disabled=1

Introduced by:
581738a681b6 ("bpf: Provide better register bounds after jmp32 instructions")
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=581738a681b6faae5725c2555439189ca81c0f1f