Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: sysctl: move the "cad_pid" entry from pid_table[] to kern_reboot_table[] cad_pid is global, and kill_cad_pid() is only used in the root namespace. However, due to pid_table_root_permissions(), a non-root user can unshare pid/user namespaces and modify it from the child namespace. This makes no sense and is simply wrong. Move it to kern_reboot_table[] where it logically belongs; this ensures that only GLOBAL_ROOT_UID can read/modify this sysctl. Note that this patch doesn't preserve "#ifdef CONFIG_PROC_SYSCTL" around the "cad_pid"; CONFIG_PROC_SYSCTL selects CONFIG_SYSCTL, so it is always set when kern_reboot_table[] is compiled.

Affected versions

Linux: e054bcbe7e7af2baad3752f1a4916a7fffc0457e through before e8527de7fea191fda704792a56081f9009aeec37 (git); e054bcbe7e7af2baad3752f1a4916a7fffc0457e through before a09bc4eaa67e1a72df3b6d0beb3afeef1e1fdfcd (git); e054bcbe7e7af2baad3752f1a4916a7fffc0457e through before 7170ca01623b399c97f2ae9d3e228badc1f25ea3 (git); 6.17 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.