Overview
About vulnerability
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.
Details
- Affected product:
- Debian 10 ELS , Debian 11 ELS
- Affected packages:
- linux @ 4.19.0 (+1 more)