Vulnerability details

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.

• https://git.kernel.org/stable/c/e8527de7fea191fda704792a56081f9009aeec37
• https://git.kernel.org/stable/c/a09bc4eaa67e1a72df3b6d0beb3afeef1e1fdfcd
• https://git.kernel.org/stable/c/7170ca01623b399c97f2ae9d3e228badc1f25ea3