4 # This script helps me to check the Linux kernel Kconfig option list
5 # against my hardening preferences for x86_64. Let the computers do their job!
7 # Author: Alexander Popov <alex.popov@linux.com>
9 # Please don't cry if my Python code looks like C.
12 # N.B Hardening command line parameters:
17 # kernel.kptr_restrict=1
20 from argparse import ArgumentParser
21 from collections import OrderedDict
24 debug_mode = False # set it to True to print the unknown options from the config
29 def __init__(self, name, expected, decision, reason):
31 self.expected = expected
32 self.decision = decision
38 if self.expected == self.state:
40 elif self.state is None:
41 if self.expected == 'is not set':
42 self.result = 'OK: not found'
44 self.result = 'FAIL: not found'
46 self.result = 'FAIL: "' + self.state + '"'
48 if self.result.startswith('OK'):
49 return True, self.result
51 return False, self.result
54 return '{} = {}'.format(self.name, self.state)
58 def __init__(self, *opts):
62 # self.opts[0] is the option which this OR-check is about.
63 # Use case: OR(<X_is_hardened>, <X_is_disabled>)
67 return self.opts[0].name
71 return self.opts[0].expected
75 return self.opts[0].state
79 return self.opts[0].decision
83 return self.opts[0].reason
86 for i, opt in enumerate(self.opts):
87 result, msg = opt.check()
90 self.result = opt.result
92 self.result = 'CONFIG_{}: {} ("{}")'.format(opt.name, opt.result, opt.expected)
93 return True, self.result
94 self.result = self.opts[0].result
95 return False, self.result
98 def construct_opt_checks():
99 devmem_not_set = OptCheck('DEVMEM', 'is not set', 'kspp', 'cut_attack_surface')
101 checklist.append(OptCheck('BUG', 'y', 'ubuntu18', 'self_protection'))
102 checklist.append(OptCheck('PAGE_TABLE_ISOLATION', 'y', 'ubuntu18', 'self_protection'))
103 checklist.append(OptCheck('RETPOLINE', 'y', 'ubuntu18', 'self_protection'))
104 checklist.append(OptCheck('X86_64', 'y', 'ubuntu18', 'self_protection'))
105 checklist.append(OptCheck('STRICT_KERNEL_RWX', 'y', 'ubuntu18', 'self_protection'))
106 checklist.append(OptCheck('STRICT_MODULE_RWX', 'y', 'ubuntu18', 'self_protection'))
107 checklist.append(OptCheck('DEBUG_WX', 'y', 'ubuntu18', 'self_protection'))
108 checklist.append(OptCheck('RANDOMIZE_BASE', 'y', 'ubuntu18', 'self_protection'))
109 checklist.append(OptCheck('RANDOMIZE_MEMORY', 'y', 'ubuntu18', 'self_protection'))
110 checklist.append(OptCheck('CC_STACKPROTECTOR', 'y', 'ubuntu18', 'self_protection'))
111 checklist.append(OptCheck('CC_STACKPROTECTOR_STRONG','y', 'ubuntu18', 'self_protection'))
112 checklist.append(OptCheck('VMAP_STACK', 'y', 'ubuntu18', 'self_protection'))
113 checklist.append(OptCheck('THREAD_INFO_IN_TASK', 'y', 'ubuntu18', 'self_protection'))
114 checklist.append(OptCheck('SCHED_STACK_END_CHECK', 'y', 'ubuntu18', 'self_protection'))
115 checklist.append(OptCheck('SLUB_DEBUG', 'y', 'ubuntu18', 'self_protection'))
116 checklist.append(OptCheck('SLAB_FREELIST_HARDENED', 'y', 'ubuntu18', 'self_protection'))
117 checklist.append(OptCheck('SLAB_FREELIST_RANDOM', 'y', 'ubuntu18', 'self_protection'))
118 checklist.append(OptCheck('HARDENED_USERCOPY', 'y', 'ubuntu18', 'self_protection'))
119 checklist.append(OptCheck('FORTIFY_SOURCE', 'y', 'ubuntu18', 'self_protection'))
120 checklist.append(OptCheck('MODULE_SIG', 'y', 'ubuntu18', 'self_protection'))
121 checklist.append(OptCheck('MODULE_SIG_ALL', 'y', 'ubuntu18', 'self_protection'))
122 checklist.append(OptCheck('MODULE_SIG_SHA512', 'y', 'ubuntu18', 'self_protection'))
123 checklist.append(OptCheck('SYN_COOKIES', 'y', 'ubuntu18', 'self_protection')) # another reason?
124 checklist.append(OptCheck('DEFAULT_MMAP_MIN_ADDR', '65536', 'ubuntu18', 'self_protection'))
126 checklist.append(OptCheck('BUG_ON_DATA_CORRUPTION', 'y', 'kspp', 'self_protection'))
127 checklist.append(OptCheck('PAGE_POISONING', 'y', 'kspp', 'self_protection'))
128 checklist.append(OptCheck('GCC_PLUGINS', 'y', 'kspp', 'self_protection'))
129 checklist.append(OptCheck('GCC_PLUGIN_RANDSTRUCT', 'y', 'kspp', 'self_protection'))
130 checklist.append(OptCheck('GCC_PLUGIN_STRUCTLEAK', 'y', 'kspp', 'self_protection'))
131 checklist.append(OptCheck('GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y', 'kspp', 'self_protection'))
132 checklist.append(OptCheck('GCC_PLUGIN_LATENT_ENTROPY', 'y', 'kspp', 'self_protection'))
133 checklist.append(OptCheck('REFCOUNT_FULL', 'y', 'kspp', 'self_protection'))
134 checklist.append(OptCheck('DEBUG_LIST', 'y', 'kspp', 'self_protection'))
135 checklist.append(OptCheck('DEBUG_SG', 'y', 'kspp', 'self_protection'))
136 checklist.append(OptCheck('DEBUG_CREDENTIALS', 'y', 'kspp', 'self_protection'))
137 checklist.append(OptCheck('DEBUG_NOTIFIERS', 'y', 'kspp', 'self_protection'))
138 checklist.append(OptCheck('MODULE_SIG_FORCE', 'y', 'kspp', 'self_protection'))
139 checklist.append(OptCheck('HARDENED_USERCOPY_FALLBACK', 'is not set', 'kspp', 'self_protection'))
141 checklist.append(OptCheck('GCC_PLUGIN_STACKLEAK', 'y', 'my', 'self_protection'))
142 checklist.append(OptCheck('SLUB_DEBUG_ON', 'y', 'my', 'self_protection'))
143 checklist.append(OptCheck('SECURITY_DMESG_RESTRICT', 'y', 'my', 'self_protection'))
144 checklist.append(OptCheck('STATIC_USERMODEHELPER', 'y', 'my', 'self_protection')) # breaks systemd?
145 checklist.append(OptCheck('PAGE_POISONING_NO_SANITY', 'is not set', 'my', 'self_protection'))
146 checklist.append(OptCheck('PAGE_POISONING_ZERO', 'is not set', 'my', 'self_protection'))
148 checklist.append(OptCheck('SECURITY', 'y', 'ubuntu18', 'security_policy'))
149 checklist.append(OptCheck('SECURITY_YAMA', 'y', 'ubuntu18', 'security_policy'))
150 checklist.append(OptCheck('SECURITY_SELINUX_DISABLE', 'is not set', 'ubuntu18', 'security_policy'))
152 checklist.append(OptCheck('SECCOMP', 'y', 'ubuntu18', 'cut_attack_surface'))
153 checklist.append(OptCheck('SECCOMP_FILTER', 'y', 'ubuntu18', 'cut_attack_surface'))
154 checklist.append(OR(OptCheck('STRICT_DEVMEM', 'y', 'ubuntu18', 'cut_attack_surface'), devmem_not_set))
155 checklist.append(OptCheck('ACPI_CUSTOM_METHOD', 'is not set', 'ubuntu18', 'cut_attack_surface'))
156 checklist.append(OptCheck('COMPAT_BRK', 'is not set', 'ubuntu18', 'cut_attack_surface'))
157 checklist.append(OptCheck('DEVKMEM', 'is not set', 'ubuntu18', 'cut_attack_surface'))
158 checklist.append(OptCheck('COMPAT_VDSO', 'is not set', 'ubuntu18', 'cut_attack_surface'))
159 checklist.append(OptCheck('X86_PTDUMP', 'is not set', 'ubuntu18', 'cut_attack_surface'))
160 checklist.append(OptCheck('ZSMALLOC_STAT', 'is not set', 'ubuntu18', 'cut_attack_surface'))
161 checklist.append(OptCheck('PAGE_OWNER', 'is not set', 'ubuntu18', 'cut_attack_surface'))
162 checklist.append(OptCheck('DEBUG_KMEMLEAK', 'is not set', 'ubuntu18', 'cut_attack_surface'))
163 checklist.append(OptCheck('BINFMT_AOUT', 'is not set', 'ubuntu18', 'cut_attack_surface'))
165 checklist.append(OR(OptCheck('IO_STRICT_DEVMEM', 'y', 'kspp', 'cut_attack_surface'), devmem_not_set))
166 checklist.append(OptCheck('LEGACY_VSYSCALL_NONE', 'y', 'kspp', 'cut_attack_surface')) # 'vsyscall=none'
167 checklist.append(OptCheck('BINFMT_MISC', 'is not set', 'kspp', 'cut_attack_surface'))
168 checklist.append(OptCheck('INET_DIAG', 'is not set', 'kspp', 'cut_attack_surface'))
169 checklist.append(OptCheck('KEXEC', 'is not set', 'kspp', 'cut_attack_surface'))
170 checklist.append(OptCheck('PROC_KCORE', 'is not set', 'kspp', 'cut_attack_surface'))
171 checklist.append(OptCheck('LEGACY_PTYS', 'is not set', 'kspp', 'cut_attack_surface'))
172 checklist.append(OptCheck('IA32_EMULATION', 'is not set', 'kspp', 'cut_attack_surface'))
173 checklist.append(OptCheck('X86_X32', 'is not set', 'kspp', 'cut_attack_surface'))
174 checklist.append(OptCheck('MODIFY_LDT_SYSCALL', 'is not set', 'kspp', 'cut_attack_surface'))
175 checklist.append(OptCheck('HIBERNATION', 'is not set', 'kspp', 'cut_attack_surface'))
177 checklist.append(OptCheck('KPROBES', 'is not set', 'grsecurity', 'cut_attack_surface'))
178 checklist.append(OptCheck('UPROBES', 'is not set', 'grsecurity', 'cut_attack_surface'))
179 checklist.append(OptCheck('GENERIC_TRACER', 'is not set', 'grsecurity', 'cut_attack_surface'))
180 checklist.append(OptCheck('PROC_VMCORE', 'is not set', 'grsecurity', 'cut_attack_surface'))
181 checklist.append(OptCheck('PROC_PAGE_MONITOR', 'is not set', 'grsecurity', 'cut_attack_surface'))
182 checklist.append(OptCheck('USELIB', 'is not set', 'grsecurity', 'cut_attack_surface'))
183 checklist.append(OptCheck('CHECKPOINT_RESTORE', 'is not set', 'grsecurity', 'cut_attack_surface'))
184 checklist.append(OptCheck('USERFAULTFD', 'is not set', 'grsecurity', 'cut_attack_surface'))
185 checklist.append(OptCheck('HWPOISON_INJECT', 'is not set', 'grsecurity', 'cut_attack_surface'))
186 checklist.append(OptCheck('MEM_SOFT_DIRTY', 'is not set', 'grsecurity', 'cut_attack_surface'))
187 checklist.append(OptCheck('DEVPORT', 'is not set', 'grsecurity', 'cut_attack_surface'))
188 checklist.append(OptCheck('DEBUG_FS', 'is not set', 'grsecurity', 'cut_attack_surface'))
189 checklist.append(OptCheck('NOTIFIER_ERROR_INJECTION','is not set', 'grsecurity', 'cut_attack_surface'))
191 checklist.append(OptCheck('KEXEC_FILE', 'is not set', 'my', 'cut_attack_surface'))
192 checklist.append(OptCheck('LIVEPATCH', 'is not set', 'my', 'cut_attack_surface'))
193 checklist.append(OptCheck('USER_NS', 'is not set', 'my', 'cut_attack_surface')) # user.max_user_namespaces=0
194 checklist.append(OptCheck('IP_DCCP', 'is not set', 'my', 'cut_attack_surface'))
195 checklist.append(OptCheck('IP_SCTP', 'is not set', 'my', 'cut_attack_surface'))
196 checklist.append(OptCheck('FTRACE', 'is not set', 'my', 'cut_attack_surface'))
197 checklist.append(OptCheck('PROFILING', 'is not set', 'my', 'cut_attack_surface'))
198 checklist.append(OptCheck('BPF_JIT', 'is not set', 'my', 'cut_attack_surface'))
199 checklist.append(OptCheck('BPF_SYSCALL', 'is not set', 'my', 'cut_attack_surface'))
201 checklist.append(OptCheck('ARCH_MMAP_RND_BITS', '32', 'my', 'userspace_protection'))
203 checklist.append(OptCheck('LKDTM', 'm', 'my', 'feature_test'))
206 def print_opt_checks():
207 print('[+] Printing kernel hardening preferences...')
208 print(' {:<39}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'))
209 print(' ======================================================================================')
210 for opt in checklist:
211 print(' CONFIG_{:<32}|{:^13}|{:^10}|{:^20}'.format(opt.name, opt.expected, opt.decision, opt.reason))
215 def print_check_results():
216 print(' {:<39}|{:^13}|{:^10}|{:^20}||{:^28}'.format('option name', 'desired val', 'decision', 'reason', 'check result'))
217 print(' ===================================================================================================================')
218 for opt in checklist:
219 print(' CONFIG_{:<32}|{:^13}|{:^10}|{:^20}||{:^28}'.format(opt.name, opt.expected, opt.decision, opt.reason, opt.result))
223 def get_option_state(options, name):
224 return options[name] if name in options else None
227 def perform_checks(parsed_options):
228 for opt in checklist:
229 if hasattr(opt, 'opts'):
231 o.state = get_option_state(parsed_options, o.name)
233 opt.state = get_option_state(parsed_options, opt.name)
237 def check_config_file(fname):
238 with open(fname, 'r') as f:
239 parsed_options = OrderedDict()
240 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
241 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
243 print('[+] Checking "{}" against hardening preferences...'.format(fname))
244 for line in f.readlines():
249 if opt_is_on.match(line):
250 option, value = line[7:].split('=', 1)
251 elif opt_is_off.match(line):
252 option, value = line[9:].split(' ', 1)
253 if value != 'is not set':
254 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
256 if option in parsed_options:
257 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
259 if option is not None:
260 parsed_options[option] = value
262 perform_checks(parsed_options)
265 known_options = [opt.name for opt in checklist]
266 for option, value in parsed_options.items():
267 if option not in known_options:
268 print("DEBUG: dunno about option {} ({})".format(option, value))
270 print_check_results()
273 if __name__ == '__main__':
274 parser = ArgumentParser(description='Checks the hardening options in the Linux kernel config')
275 parser.add_argument('-p', '--print', action='store_true', help='print hardening preferences')
276 parser.add_argument('-c', '--config', help='check the config_file against these preferences')
277 parser.add_argument('--debug', action='store_true', help='enable internal debug mode')
278 args = parser.parse_args()
280 construct_opt_checks()
290 check_config_file(args.config)
291 error_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
293 print('[+] config check is PASSED')
296 sys.exit('[-] config check is NOT PASSED: {} errors'.format(error_count))