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
30 def __init__(self, name, expected, decision, reason):
32 self.expected = expected
33 self.decision = decision
41 if self.expected == self.state:
43 return True, self.result
46 if self.state is None:
47 if self.expected == 'is not set':
48 self.result = 'OK: not found'
49 return True, self.result
52 self.result = 'FAIL: not found'
53 return False, self.result
56 self.result = 'FAIL: "' + self.state + '"'
57 return False, self.result
60 return '{} = {}'.format(self.name, self.state)
63 def construct_opt_checks():
64 opt_list.append(Opt('BUG', 'y', 'ubuntu18', 'self_protection'))
65 opt_list.append(Opt('PAGE_TABLE_ISOLATION', 'y', 'ubuntu18', 'self_protection'))
66 opt_list.append(Opt('RETPOLINE', 'y', 'ubuntu18', 'self_protection'))
67 opt_list.append(Opt('X86_64', 'y', 'ubuntu18', 'self_protection'))
68 opt_list.append(Opt('STRICT_KERNEL_RWX', 'y', 'ubuntu18', 'self_protection'))
69 opt_list.append(Opt('STRICT_MODULE_RWX', 'y', 'ubuntu18', 'self_protection'))
70 opt_list.append(Opt('DEBUG_WX', 'y', 'ubuntu18', 'self_protection'))
71 opt_list.append(Opt('RANDOMIZE_BASE', 'y', 'ubuntu18', 'self_protection'))
72 opt_list.append(Opt('RANDOMIZE_MEMORY', 'y', 'ubuntu18', 'self_protection'))
73 opt_list.append(Opt('CC_STACKPROTECTOR', 'y', 'ubuntu18', 'self_protection'))
74 opt_list.append(Opt('CC_STACKPROTECTOR_STRONG','y', 'ubuntu18', 'self_protection'))
75 opt_list.append(Opt('VMAP_STACK', 'y', 'ubuntu18', 'self_protection'))
76 opt_list.append(Opt('THREAD_INFO_IN_TASK', 'y', 'ubuntu18', 'self_protection'))
77 opt_list.append(Opt('SCHED_STACK_END_CHECK', 'y', 'ubuntu18', 'self_protection'))
78 opt_list.append(Opt('SLUB_DEBUG', 'y', 'ubuntu18', 'self_protection'))
79 opt_list.append(Opt('SLAB_FREELIST_HARDENED', 'y', 'ubuntu18', 'self_protection'))
80 opt_list.append(Opt('SLAB_FREELIST_RANDOM', 'y', 'ubuntu18', 'self_protection'))
81 opt_list.append(Opt('HARDENED_USERCOPY', 'y', 'ubuntu18', 'self_protection'))
82 opt_list.append(Opt('FORTIFY_SOURCE', 'y', 'ubuntu18', 'self_protection'))
83 opt_list.append(Opt('MODULE_SIG', 'y', 'ubuntu18', 'self_protection'))
84 opt_list.append(Opt('MODULE_SIG_ALL', 'y', 'ubuntu18', 'self_protection'))
85 opt_list.append(Opt('MODULE_SIG_SHA512', 'y', 'ubuntu18', 'self_protection'))
86 opt_list.append(Opt('SYN_COOKIES', 'y', 'ubuntu18', 'self_protection')) # another reason?
87 opt_list.append(Opt('DEFAULT_MMAP_MIN_ADDR', '65536', 'ubuntu18', 'self_protection'))
89 opt_list.append(Opt('BUG_ON_DATA_CORRUPTION', 'y', 'kspp', 'self_protection'))
90 opt_list.append(Opt('PAGE_POISONING', 'y', 'kspp', 'self_protection'))
91 opt_list.append(Opt('GCC_PLUGINS', 'y', 'kspp', 'self_protection'))
92 opt_list.append(Opt('GCC_PLUGIN_RANDSTRUCT', 'y', 'kspp', 'self_protection'))
93 opt_list.append(Opt('GCC_PLUGIN_STRUCTLEAK', 'y', 'kspp', 'self_protection'))
94 opt_list.append(Opt('GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y', 'kspp', 'self_protection'))
95 opt_list.append(Opt('GCC_PLUGIN_LATENT_ENTROPY', 'y', 'kspp', 'self_protection'))
96 opt_list.append(Opt('REFCOUNT_FULL', 'y', 'kspp', 'self_protection'))
97 opt_list.append(Opt('DEBUG_LIST', 'y', 'kspp', 'self_protection'))
98 opt_list.append(Opt('DEBUG_SG', 'y', 'kspp', 'self_protection'))
99 opt_list.append(Opt('DEBUG_CREDENTIALS', 'y', 'kspp', 'self_protection'))
100 opt_list.append(Opt('DEBUG_NOTIFIERS', 'y', 'kspp', 'self_protection'))
101 opt_list.append(Opt('MODULE_SIG_FORCE', 'y', 'kspp', 'self_protection'))
102 opt_list.append(Opt('HARDENED_USERCOPY_FALLBACK', 'is not set', 'kspp', 'self_protection'))
104 opt_list.append(Opt('GCC_PLUGIN_STACKLEAK', 'y', 'my', 'self_protection'))
105 opt_list.append(Opt('SLUB_DEBUG_ON', 'y', 'my', 'self_protection'))
106 opt_list.append(Opt('SECURITY_DMESG_RESTRICT', 'y', 'my', 'self_protection'))
107 opt_list.append(Opt('STATIC_USERMODEHELPER', 'y', 'my', 'self_protection')) # breaks systemd?
108 opt_list.append(Opt('PAGE_POISONING_NO_SANITY', 'is not set', 'my', 'self_protection'))
109 opt_list.append(Opt('PAGE_POISONING_ZERO', 'is not set', 'my', 'self_protection'))
111 opt_list.append(Opt('SECURITY', 'y', 'ubuntu18', 'security_policy'))
112 opt_list.append(Opt('SECURITY_YAMA', 'y', 'ubuntu18', 'security_policy'))
113 opt_list.append(Opt('SECURITY_SELINUX_DISABLE', 'is not set', 'ubuntu18', 'security_policy'))
115 opt_list.append(Opt('SECCOMP', 'y', 'ubuntu18', 'cut_attack_surface'))
116 opt_list.append(Opt('SECCOMP_FILTER', 'y', 'ubuntu18', 'cut_attack_surface'))
117 opt_list.append(Opt('STRICT_DEVMEM', 'y', 'ubuntu18', 'cut_attack_surface'))
118 opt_list.append(Opt('ACPI_CUSTOM_METHOD', 'is not set', 'ubuntu18', 'cut_attack_surface'))
119 opt_list.append(Opt('COMPAT_BRK', 'is not set', 'ubuntu18', 'cut_attack_surface'))
120 opt_list.append(Opt('DEVKMEM', 'is not set', 'ubuntu18', 'cut_attack_surface'))
121 opt_list.append(Opt('COMPAT_VDSO', 'is not set', 'ubuntu18', 'cut_attack_surface'))
122 opt_list.append(Opt('X86_PTDUMP', 'is not set', 'ubuntu18', 'cut_attack_surface'))
123 opt_list.append(Opt('ZSMALLOC_STAT', 'is not set', 'ubuntu18', 'cut_attack_surface'))
124 opt_list.append(Opt('PAGE_OWNER', 'is not set', 'ubuntu18', 'cut_attack_surface'))
125 opt_list.append(Opt('DEBUG_KMEMLEAK', 'is not set', 'ubuntu18', 'cut_attack_surface'))
127 opt_list.append(Opt('IO_STRICT_DEVMEM', 'y', 'kspp', 'cut_attack_surface'))
128 opt_list.append(Opt('LEGACY_VSYSCALL_NONE', 'y', 'kspp', 'cut_attack_surface')) # 'vsyscall=none'
129 opt_list.append(Opt('BINFMT_MISC', 'is not set', 'kspp', 'cut_attack_surface'))
130 opt_list.append(Opt('INET_DIAG', 'is not set', 'kspp', 'cut_attack_surface'))
131 opt_list.append(Opt('KEXEC', 'is not set', 'kspp', 'cut_attack_surface'))
132 opt_list.append(Opt('PROC_KCORE', 'is not set', 'kspp', 'cut_attack_surface'))
133 opt_list.append(Opt('LEGACY_PTYS', 'is not set', 'kspp', 'cut_attack_surface'))
134 opt_list.append(Opt('IA32_EMULATION', 'is not set', 'kspp', 'cut_attack_surface'))
135 opt_list.append(Opt('X86_X32', 'is not set', 'kspp', 'cut_attack_surface'))
136 opt_list.append(Opt('MODIFY_LDT_SYSCALL', 'is not set', 'kspp', 'cut_attack_surface'))
137 opt_list.append(Opt('HIBERNATION', 'is not set', 'kspp', 'cut_attack_surface'))
139 opt_list.append(Opt('KPROBES', 'is not set', 'grsecurity', 'cut_attack_surface'))
140 opt_list.append(Opt('UPROBES', 'is not set', 'grsecurity', 'cut_attack_surface'))
141 opt_list.append(Opt('GENERIC_TRACER', 'is not set', 'grsecurity', 'cut_attack_surface'))
142 opt_list.append(Opt('PROC_VMCORE', 'is not set', 'grsecurity', 'cut_attack_surface'))
143 opt_list.append(Opt('PROC_PAGE_MONITOR', 'is not set', 'grsecurity', 'cut_attack_surface'))
144 opt_list.append(Opt('USELIB', 'is not set', 'grsecurity', 'cut_attack_surface'))
145 opt_list.append(Opt('CHECKPOINT_RESTORE', 'is not set', 'grsecurity', 'cut_attack_surface'))
146 opt_list.append(Opt('USERFAULTFD', 'is not set', 'grsecurity', 'cut_attack_surface'))
147 opt_list.append(Opt('HWPOISON_INJECT', 'is not set', 'grsecurity', 'cut_attack_surface'))
148 opt_list.append(Opt('MEM_SOFT_DIRTY', 'is not set', 'grsecurity', 'cut_attack_surface'))
149 opt_list.append(Opt('DEVPORT', 'is not set', 'grsecurity', 'cut_attack_surface'))
150 opt_list.append(Opt('DEBUG_FS', 'is not set', 'grsecurity', 'cut_attack_surface'))
151 opt_list.append(Opt('NOTIFIER_ERROR_INJECTION','is not set', 'grsecurity', 'cut_attack_surface'))
153 opt_list.append(Opt('KEXEC_FILE', 'is not set', 'my', 'cut_attack_surface'))
154 opt_list.append(Opt('LIVEPATCH', 'is not set', 'my', 'cut_attack_surface'))
155 opt_list.append(Opt('USER_NS', 'is not set', 'my', 'cut_attack_surface')) # user.max_user_namespaces=0
156 opt_list.append(Opt('IP_DCCP', 'is not set', 'my', 'cut_attack_surface'))
157 opt_list.append(Opt('IP_SCTP', 'is not set', 'my', 'cut_attack_surface'))
158 opt_list.append(Opt('FTRACE', 'is not set', 'my', 'cut_attack_surface'))
159 opt_list.append(Opt('PROFILING', 'is not set', 'my', 'cut_attack_surface'))
160 opt_list.append(Opt('BPF_JIT', 'is not set', 'my', 'cut_attack_surface'))
161 opt_list.append(Opt('BPF_SYSCALL', 'is not set', 'my', 'cut_attack_surface'))
163 opt_list.append(Opt('ARCH_MMAP_RND_BITS', '32', 'my', 'userspace_protection'))
165 opt_list.append(Opt('LKDTM', 'm', 'my', 'feature_test'))
168 def print_opt_checks():
169 print('[+] Printing kernel hardening preferences...')
170 print(' {:<39}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'))
171 print(' ======================================================================================')
173 print(' CONFIG_{:<32}|{:^13}|{:^10}|{:^20}'.format(opt.name, opt.expected, opt.decision, opt.reason))
177 def print_check_results():
180 print(' {:<39}|{:^13}|{:^10}|{:^20}||{:^20}'.format('option name', 'desired val', 'decision', 'reason', 'check result'))
181 print(' ===========================================================================================================')
183 print(' CONFIG_{:<32}|{:^13}|{:^10}|{:^20}||{:^20}'.format(opt.name, opt.expected, opt.decision, opt.reason, opt.result))
187 def get_option_state(options, name):
188 return options[name] if name in options else None
191 def perform_checks(parsed_options):
193 opt.state = get_option_state(parsed_options, opt.name)
197 def check_config_file(fname):
198 with open(fname, 'r') as f:
199 parsed_options = OrderedDict()
200 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
201 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
203 print('[+] Checking "{}" against hardening preferences...'.format(fname))
204 for line in f.readlines():
209 if opt_is_on.match(line):
210 option, value = line[7:].split('=', 1)
211 elif opt_is_off.match(line):
212 option, value = line[9:].split(' ', 1)
213 if value != 'is not set':
214 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
216 if option in parsed_options:
217 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
219 if option is not None:
220 parsed_options[option] = value
222 perform_checks(parsed_options)
225 known_options = [opt.name for opt in opt_list]
226 for option, value in parsed_options.items():
227 if option not in known_options:
228 print("DEBUG: dunno about option {} ({})".format(option, value))
230 print_check_results()
233 if __name__ == '__main__':
234 parser = ArgumentParser(description='Checks the hardening options in the Linux kernel config')
235 parser.add_argument('-p', '--print', action='store_true', help='print hardening preferences')
236 parser.add_argument('-c', '--config', help='check the config_file against these preferences')
237 parser.add_argument('--debug', action='store_true', help='enable internal debug mode')
238 args = parser.parse_args()
240 construct_opt_checks()
250 check_config_file(args.config)
252 print('[+] config check is PASSED')
255 sys.exit('[-] config check is NOT PASSED: {} errors'.format(error_count))