{"description": "To enable the randomization of the page allocator in the kernel, check that\nall boot entries in <tt>/boot/loader/entries/*.conf</tt> have\n<tt>page_alloc.shuffle=1</tt> included in its options.<br />\n\nTo enable randomization of the page allocator also for  newly installed\nkernels, add <tt>page_alloc.shuffle=1</tt> to <tt>/etc/kernel/cmdline</tt>.", "rationale": "The <tt>CONFIG_SHUFFLE_PAGE_ALLOCATOR</tt> config option is primarily\nfocused on improving the average utilization of a direct-mapped\nmemory-side-cache. Aside of this performance effect, it also reduces\npredictability of page allocations in situations when the bad actor can\ncrash the system and somehow leverage knowledge of (page) allocation order\nright after a fresh reboot, or can control the timing between a\nhot-pluggable memory node (as in NUMA node) and applications allocating\nmemory ouf of that node. The <tt>page_alloc.shuffle=1</tt> kernel command\nline parameter then forces this functionality irrespectively of memory cache\narchitecture.", "severity": "medium", "references": {"ospp": ["AVA_VAN.1"]}, "control_references": {}, "components": [], "identifiers": {}, "ocil_clause": "randomization of the page allocator is not enabled in the kernel", "ocil": "To check that the randomization of the page allocator in the kernel is\nenabled, check all boot entries with following command:\n<pre>sudo grep -L\"^options\\s+.*\\bpage_alloc\\.shuffle=1\\b\" /boot/loader/entries/*.conf</pre>\nNo line should be returned, each line returned is a boot entry that doesn't enable audit.", "oval_external_content": null, "fixtext": "", "checktext": "", "vuldiscussion": "", "srg_requirement": "", "warnings": [], "conflicts": [], "requires": [], "policy_specific_content": {}, "platform": "machine", "platforms": ["machine"], "sce_metadata": {}, "inherited_platforms": ["s390x_arch"], "cpe_platform_names": ["machine"], "inherited_cpe_platform_names": ["s390x_arch"], "bash_conditional": null, "fixes": {}, "title": "Enable randomization of the page allocator in zIPL", "definition_location": "/aptdata/openscap/scap-security-guide/linux_os/guide/system/bootloader-zipl/zipl_page_alloc_shuffle_argument/rule.yml", "template": {"name": "zipl_bls_entries_option", "vars": {"arg_name": "page_alloc.shuffle", "arg_value": "1"}, "backends": {}}}