Acknowledged
Created: Oct 21, 2024
Updated: Feb 18, 2026
Resolved Date: Feb 2, 2026
Found In Version: 10.21.20.1
Severity: Standard
Applicable for: Wind River Linux LTS 21
Component/s: Kernel
In the Linux kernel, the following vulnerability has been resolved:
bpf, lsm: Add check for BPF LSM return value
A bpf prog returning a positive number attached to file_alloc_security
hook makes kernel panic.
This happens because file system can not filter out the positive number
returned by the LSM prog using IS_ERR, and misinterprets this positive
number as a file pointer.
Given that hook file_alloc_security never returned positive number
before the introduction of BPF LSM, and other BPF LSM hooks may
encounter similar issues, this patch adds LSM return value check
in verifier, to ensure no unexpected value is returned.
========Wind River Notice========
Mitigation:
Customers can use kernel.unprivileged_bpf_disabled sysctl to prevent unprivileged users from being able to use eBPF. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.
Inspect kernel.unprivileged_bpf_disabled 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.
echo 1 > /proc/sys/kernel/unprivileged_bpf_disabled
For more details, please refer to Linux kernel official document:
https://docs.kernel.org/admin-guide/sysctl/kernel.html#unprivileged-bpf-disabled
