{"description": "To disable use of virtual syscalls,\ncheck that all boot entries in <tt>/boot/loader/entries/*.conf</tt> have <tt>vsyscall=none</tt>\nincluded in its options.<br />\nTo ensure that new kernels and boot entries continue to disable virtual syscalls,\nadd <tt>vsyscall=none</tt> to <tt>/etc/kernel/cmdline</tt>.", "rationale": "Virtual Syscalls provide an opportunity of attack for a user who has control\nof the return instruction pointer.", "severity": "medium", "references": {"ospp": ["FPT_ASLR_EXT.1"]}, "control_references": {}, "components": [], "identifiers": {}, "ocil_clause": "vsyscalls are enabled", "ocil": "To check that virtual syscalls are disabled at boot time, check all boot entries with following command:\n<pre>sudo grep -L \"^options\\s+.*\\bvsyscall=none\\b\" /boot/loader/entries/*.conf</pre>\nNo line should be returned, each line returned is a boot entry that doesn't disable virtual syscalls.", "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": "Disable vsyscalls in zIPL", "definition_location": "/aptdata/openscap/scap-security-guide/linux_os/guide/system/bootloader-zipl/zipl_vsyscall_argument/rule.yml", "template": {"name": "zipl_bls_entries_option", "vars": {"arg_name": "vsyscall", "arg_value": "none"}, "backends": {}}}