CVE-2022-3534
Description
A use-after-free flaw was found in btf_dump_name_dups in tools/lib/bpf/btf_dump.c in libbpf in the Linux Kernel. This issue occurs because the key stored in the hash table name_map is a string address, and the string memory is allocated by realloc() function. When the memory is resized by realloc() later, the old memory may be freed.
Mitigation
The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.
For the Red Hat Enterprise Linux 8 to confirm the current state, inspect the sysctl with the command:
# cat /proc/sys/kernel/unprivileged_bpf_disabled
The setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | 8 | 5.5 |
| Attack Vector | Adjacent Network | Adjacent Network | Adjacent Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | High | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | High | Low |
| Integrity Impact | Low | High | Low |
| Availability Impact | Low | High | Low |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/RL:O/RC:C
Red Hat CVSS v3 Score Explanation
The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.
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