Information
Exposing kernel pointers (through procfs or 'seq_printf()') exposes kernel writeable structures, which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallows any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with '0'.
Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227
Solution
Add or edit the following line in a system configuration file in the '/etc/sysctl.d/' directory:
kernel.kptr_restrict = 1
Reload settings from all system configuration files with the following command:
$ sudo sysctl --system