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 collections import namedtuple
23 debug_mode = False # set it to True to print the unknown options from the config
27 Opt = namedtuple('Opt', ['name', 'state', 'decision', 'reason'])
29 def construct_opt_list():
30 opt_list.append([Opt('BUG', 'y', 'ubuntu18', 'self_protection'), ''])
31 opt_list.append([Opt('PAGE_TABLE_ISOLATION', 'y', 'ubuntu18', 'self_protection'), ''])
32 opt_list.append([Opt('RETPOLINE', 'y', 'ubuntu18', 'self_protection'), ''])
33 opt_list.append([Opt('X86_64', 'y', 'ubuntu18', 'self_protection'), ''])
34 opt_list.append([Opt('STRICT_KERNEL_RWX', 'y', 'ubuntu18', 'self_protection'), ''])
35 opt_list.append([Opt('STRICT_MODULE_RWX', 'y', 'ubuntu18', 'self_protection'), ''])
36 opt_list.append([Opt('DEBUG_WX', 'y', 'ubuntu18', 'self_protection'), ''])
37 opt_list.append([Opt('RANDOMIZE_BASE', 'y', 'ubuntu18', 'self_protection'), ''])
38 opt_list.append([Opt('RANDOMIZE_MEMORY', 'y', 'ubuntu18', 'self_protection'), ''])
39 opt_list.append([Opt('CC_STACKPROTECTOR_STRONG','y', 'ubuntu18', 'self_protection'), ''])
40 opt_list.append([Opt('VMAP_STACK', 'y', 'ubuntu18', 'self_protection'), ''])
41 opt_list.append([Opt('THREAD_INFO_IN_TASK', 'y', 'ubuntu18', 'self_protection'), ''])
42 opt_list.append([Opt('SCHED_STACK_END_CHECK', 'y', 'ubuntu18', 'self_protection'), ''])
43 opt_list.append([Opt('SLUB_DEBUG', 'y', 'ubuntu18', 'self_protection'), ''])
44 opt_list.append([Opt('SLAB_FREELIST_HARDENED', 'y', 'ubuntu18', 'self_protection'), ''])
45 opt_list.append([Opt('SLAB_FREELIST_RANDOM', 'y', 'ubuntu18', 'self_protection'), ''])
46 opt_list.append([Opt('HARDENED_USERCOPY', 'y', 'ubuntu18', 'self_protection'), ''])
47 opt_list.append([Opt('FORTIFY_SOURCE', 'y', 'ubuntu18', 'self_protection'), ''])
48 opt_list.append([Opt('STRICT_DEVMEM', 'y', 'ubuntu18', 'self_protection'), ''])
49 opt_list.append([Opt('SYN_COOKIES', 'y', 'ubuntu18', 'self_protection'), ''])
50 opt_list.append([Opt('SECCOMP', 'y', 'ubuntu18', 'self_protection'), ''])
51 opt_list.append([Opt('SECCOMP_FILTER', 'y', 'ubuntu18', 'self_protection'), ''])
52 opt_list.append([Opt('MODULE_SIG', 'y', 'ubuntu18', 'self_protection'), ''])
53 opt_list.append([Opt('MODULE_SIG_ALL', 'y', 'ubuntu18', 'self_protection'), ''])
54 opt_list.append([Opt('MODULE_SIG_SHA512', 'y', 'ubuntu18', 'self_protection'), ''])
55 opt_list.append([Opt('DEFAULT_MMAP_MIN_ADDR', '65536', 'ubuntu18', 'self_protection'), ''])
57 opt_list.append([Opt('BUG_ON_DATA_CORRUPTION', 'y', 'kspp', 'self_protection'), ''])
58 opt_list.append([Opt('PAGE_POISONING', 'y', 'kspp', 'self_protection'), ''])
59 opt_list.append([Opt('GCC_PLUGINS', 'y', 'kspp', 'self_protection'), ''])
60 opt_list.append([Opt('GCC_PLUGIN_RANDSTRUCT', 'y', 'kspp', 'self_protection'), ''])
61 opt_list.append([Opt('GCC_PLUGIN_STRUCTLEAK', 'y', 'kspp', 'self_protection'), ''])
62 opt_list.append([Opt('GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y', 'kspp', 'self_protection'), ''])
63 opt_list.append([Opt('GCC_PLUGIN_LATENT_ENTROPY', 'y', 'kspp', 'self_protection'), ''])
64 opt_list.append([Opt('IO_STRICT_DEVMEM', 'y', 'kspp', 'self_protection'), ''])
65 opt_list.append([Opt('REFCOUNT_FULL', 'y', 'kspp', 'self_protection'), ''])
66 opt_list.append([Opt('DEBUG_LIST', 'y', 'kspp', 'self_protection'), ''])
67 opt_list.append([Opt('DEBUG_SG', 'y', 'kspp', 'self_protection'), ''])
68 opt_list.append([Opt('DEBUG_CREDENTIALS', 'y', 'kspp', 'self_protection'), ''])
69 opt_list.append([Opt('DEBUG_NOTIFIERS', 'y', 'kspp', 'self_protection'), ''])
70 opt_list.append([Opt('MODULE_SIG_FORCE', 'y', 'kspp', 'self_protection'), ''])
71 opt_list.append([Opt('HARDENED_USERCOPY_FALLBACK', 'is not set', 'kspp', 'self_protection'), ''])
72 opt_list.append([Opt('GCC_PLUGIN_STACKLEAK', 'y', 'my', 'self_protection'), ''])
73 opt_list.append([Opt('SLUB_DEBUG_ON', 'y', 'my', 'self_protection'), ''])
74 opt_list.append([Opt('SECURITY_DMESG_RESTRICT', 'y', 'my', 'self_protection'), ''])
75 opt_list.append([Opt('STATIC_USERMODEHELPER', 'y', 'my', 'self_protection'), '']) # breaks systemd?
77 opt_list.append([Opt('SECURITY', 'y', 'ubuntu18', 'security_policy'), ''])
78 opt_list.append([Opt('SECURITY_YAMA', 'y', 'ubuntu18', 'security_policy'), ''])
79 opt_list.append([Opt('SECURITY_SELINUX_DISABLE', 'is not set', 'ubuntu18', 'security_policy'), ''])
81 opt_list.append([Opt('ACPI_CUSTOM_METHOD', 'is not set', 'ubuntu18', 'cut_attack_surface'), ''])
82 opt_list.append([Opt('COMPAT_BRK', 'is not set', 'ubuntu18', 'cut_attack_surface'), ''])
83 opt_list.append([Opt('DEVKMEM', 'is not set', 'ubuntu18', 'cut_attack_surface'), ''])
84 opt_list.append([Opt('COMPAT_VDSO', 'is not set', 'ubuntu18', 'cut_attack_surface'), ''])
86 opt_list.append([Opt('LEGACY_VSYSCALL_NONE', 'y', 'kspp', 'cut_attack_surface'), '']) # 'vsyscall=none'
87 opt_list.append([Opt('BINFMT_MISC', 'is not set', 'kspp', 'cut_attack_surface'), ''])
88 opt_list.append([Opt('INET_DIAG', 'is not set', 'kspp', 'cut_attack_surface'), ''])
89 opt_list.append([Opt('KEXEC', 'is not set', 'kspp', 'cut_attack_surface'), ''])
90 opt_list.append([Opt('PROC_KCORE', 'is not set', 'kspp', 'cut_attack_surface'), ''])
91 opt_list.append([Opt('LEGACY_PTYS', 'is not set', 'kspp', 'cut_attack_surface'), ''])
92 opt_list.append([Opt('IA32_EMULATION', 'is not set', 'kspp', 'cut_attack_surface'), ''])
93 opt_list.append([Opt('X86_X32', 'is not set', 'kspp', 'cut_attack_surface'), ''])
94 opt_list.append([Opt('MODIFY_LDT_SYSCALL', 'is not set', 'kspp', 'cut_attack_surface'), ''])
95 opt_list.append([Opt('KEXEC_FILE', 'is not set', 'my', 'cut_attack_surface'), ''])
96 opt_list.append([Opt('LIVEPATCH', 'is not set', 'my', 'cut_attack_surface'), ''])
97 opt_list.append([Opt('NAMESPACES', 'is not set', 'my', 'cut_attack_surface'), '']) # user.max_user_namespaces=0
98 opt_list.append([Opt('IP_DCCP', 'is not set', 'my', 'cut_attack_surface'), ''])
99 opt_list.append([Opt('FTRACE', 'is not set', 'my', 'cut_attack_surface'), ''])
100 opt_list.append([Opt('KPROBES', 'is not set', 'my', 'cut_attack_surface'), ''])
101 opt_list.append([Opt('PROFILING', 'is not set', 'my', 'cut_attack_surface'), ''])
102 opt_list.append([Opt('UPROBES', 'is not set', 'my', 'cut_attack_surface'), ''])
103 opt_list.append([Opt('BPF_JIT', 'is not set', 'my', 'cut_attack_surface'), ''])
104 opt_list.append([Opt('BPF_SYSCALL', 'is not set', 'my', 'cut_attack_surface'), ''])
106 opt_list.append([Opt('LKDTM', 'm', 'my', 'feature_test'), ''])
109 def print_opt_list():
110 print('[+] Printing kernel hardening preferences...')
111 print(' {:<39}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'))
112 print(' ======================================================================================')
114 print(' CONFIG_{:<32}|{:^13}|{:^10}|{:^20}'.format(o[0].name, o[0].state, o[0].decision, o[0].reason))
118 def print_check_results():
121 print(' {:<39}|{:^13}|{:^10}|{:^20}||{:^20}'.format('option name', 'desired val', 'decision', 'reason', 'check result'))
122 print(' ===========================================================================================================')
126 o[1] = 'FAIL: not found'
127 print(' CONFIG_{:<32}|{:^13}|{:^10}|{:^20}||{:^20}'.format(o[0].name, o[0].state, o[0].decision, o[0].reason, o[1]))
131 def check_state(option):
136 if option[0] == o[0].name:
140 sys.exit('[!] BUG: CONFIG_{} was found more than once'.format(o[0].name))
142 if option[1] == o[0].state:
145 o[1] = 'FAIL: "' + option[1] + '"'
148 if not found and debug_mode:
149 print("DEBUG: dunno about option {} ".format(option))
153 if line[:7] != 'CONFIG_':
154 sys.exit('[!] BUG: bad enabled config option "{}"'.format(line))
156 line_parts = line[7:].split('=')
157 check_state(line_parts)
161 if line[:9] != '# CONFIG_':
162 sys.exit('[!] BUG: bad disabled config option "{}"'.format(line))
164 line_parts = line[9:].split(' ', 1)
166 if line_parts[1] != 'is not set':
167 sys.exit('[!] BUG: bad disabled config option "{}"'.format(line))
169 check_state(line_parts)
172 def check_config_file(fname):
175 print('[+] Checking "{}" against hardening preferences...'.format(fname))
177 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
178 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
179 if opt_is_on.match(line):
180 check_on(line[:-1]) # drop newline
181 if opt_is_off.match(line):
182 check_off(line[:-1]) # ditto
184 print_check_results()
189 print('Usage: {} [-p | -c <config_file>] '.format(name))
190 print(' -p, --print\n\tprint hardening preferences')
191 print(' -c <config_file>, --config=<config_file>\n\tcheck the config_file against these preferences')
197 opts, args = getopt.getopt(argv[1:], 'pc:', ['print', 'config='])
198 except getopt.GetoptError:
206 for opt, arg in opts:
207 if opt in ('-p', '--print'):
210 elif opt in ('-c', '--config'):
211 check_config_file(arg)
213 print('[+] config check is PASSED')
215 sys.exit('[-] config check is NOT PASSED: {} errors'.format(error_count))