diff options
Diffstat (limited to 'contrib/devtools/security-check.py')
| -rwxr-xr-x | contrib/devtools/security-check.py | 147 |
1 files changed, 50 insertions, 97 deletions
diff --git a/contrib/devtools/security-check.py b/contrib/devtools/security-check.py index 7b09c42fde..0b59d8eada 100755 --- a/contrib/devtools/security-check.py +++ b/contrib/devtools/security-check.py @@ -6,22 +6,13 @@ Perform basic security checks on a series of executables. Exit status will be 0 if successful, and the program will be silent. Otherwise the exit status will be 1 and it will log which executables failed which checks. -Needs `objdump` (for PE) and `otool` (for MACHO). ''' -import subprocess import sys -import os from typing import List, Optional +import lief import pixie -OBJDUMP_CMD = os.getenv('OBJDUMP', '/usr/bin/objdump') -OTOOL_CMD = os.getenv('OTOOL', '/usr/bin/otool') - -def run_command(command) -> str: - p = subprocess.run(command, stdout=subprocess.PIPE, check=True, universal_newlines=True) - return p.stdout - def check_ELF_PIE(executable) -> bool: ''' Check for position independent executable (PIE), allowing for address space randomization. @@ -143,112 +134,72 @@ def check_ELF_separate_code(executable): return False return True -def get_PE_dll_characteristics(executable) -> int: - '''Get PE DllCharacteristics bits''' - stdout = run_command([OBJDUMP_CMD, '-x', executable]) - - bits = 0 - for line in stdout.splitlines(): - tokens = line.split() - if len(tokens)>=2 and tokens[0] == 'DllCharacteristics': - bits = int(tokens[1],16) - return bits - -IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA = 0x0020 -IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE = 0x0040 -IMAGE_DLL_CHARACTERISTICS_NX_COMPAT = 0x0100 - def check_PE_DYNAMIC_BASE(executable) -> bool: '''PIE: DllCharacteristics bit 0x40 signifies dynamicbase (ASLR)''' - bits = get_PE_dll_characteristics(executable) - return (bits & IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE) == IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE + binary = lief.parse(executable) + return lief.PE.DLL_CHARACTERISTICS.DYNAMIC_BASE in binary.optional_header.dll_characteristics_lists # Must support high-entropy 64-bit address space layout randomization # in addition to DYNAMIC_BASE to have secure ASLR. def check_PE_HIGH_ENTROPY_VA(executable) -> bool: '''PIE: DllCharacteristics bit 0x20 signifies high-entropy ASLR''' - bits = get_PE_dll_characteristics(executable) - return (bits & IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA) == IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA + binary = lief.parse(executable) + return lief.PE.DLL_CHARACTERISTICS.HIGH_ENTROPY_VA in binary.optional_header.dll_characteristics_lists def check_PE_RELOC_SECTION(executable) -> bool: '''Check for a reloc section. This is required for functional ASLR.''' - stdout = run_command([OBJDUMP_CMD, '-h', executable]) + binary = lief.parse(executable) + return binary.has_relocations - for line in stdout.splitlines(): - if '.reloc' in line: - return True - return False - -def check_PE_NX(executable) -> bool: - '''NX: DllCharacteristics bit 0x100 signifies nxcompat (DEP)''' - bits = get_PE_dll_characteristics(executable) - return (bits & IMAGE_DLL_CHARACTERISTICS_NX_COMPAT) == IMAGE_DLL_CHARACTERISTICS_NX_COMPAT - -def get_MACHO_executable_flags(executable) -> List[str]: - stdout = run_command([OTOOL_CMD, '-vh', executable]) +def check_MACHO_NOUNDEFS(executable) -> bool: + ''' + Check for no undefined references. + ''' + binary = lief.parse(executable) + return binary.header.has(lief.MachO.HEADER_FLAGS.NOUNDEFS) - flags: List[str] = [] - for line in stdout.splitlines(): - tokens = line.split() - # filter first two header lines - if 'magic' in tokens or 'Mach' in tokens: - continue - # filter ncmds and sizeofcmds values - flags += [t for t in tokens if not t.isdigit()] - return flags +def check_MACHO_LAZY_BINDINGS(executable) -> bool: + ''' + Check for no lazy bindings. + We don't use or check for MH_BINDATLOAD. See #18295. + ''' + binary = lief.parse(executable) + return binary.dyld_info.lazy_bind == (0,0) -def check_MACHO_PIE(executable) -> bool: +def check_MACHO_Canary(executable) -> bool: ''' - Check for position independent executable (PIE), allowing for address space randomization. + Check for use of stack canary ''' - flags = get_MACHO_executable_flags(executable) - if 'PIE' in flags: - return True - return False + binary = lief.parse(executable) + return binary.has_symbol('___stack_chk_fail') -def check_MACHO_NOUNDEFS(executable) -> bool: +def check_PIE(executable) -> bool: ''' - Check for no undefined references. + Check for position independent executable (PIE), + allowing for address space randomization. ''' - flags = get_MACHO_executable_flags(executable) - if 'NOUNDEFS' in flags: - return True - return False + binary = lief.parse(executable) + return binary.is_pie -def check_MACHO_NX(executable) -> bool: +def check_NX(executable) -> bool: ''' Check for no stack execution ''' - flags = get_MACHO_executable_flags(executable) - if 'ALLOW_STACK_EXECUTION' in flags: - return False - return True + binary = lief.parse(executable) + return binary.has_nx -def check_MACHO_LAZY_BINDINGS(executable) -> bool: +def check_control_flow(executable) -> bool: ''' - Check for no lazy bindings. - We don't use or check for MH_BINDATLOAD. See #18295. + Check for control flow instrumentation ''' - stdout = run_command([OTOOL_CMD, '-l', executable]) + binary = lief.parse(executable) - for line in stdout.splitlines(): - tokens = line.split() - if 'lazy_bind_off' in tokens or 'lazy_bind_size' in tokens: - if tokens[1] != '0': - return False - return True + content = binary.get_content_from_virtual_address(binary.entrypoint, 4, lief.Binary.VA_TYPES.AUTO) -def check_MACHO_Canary(executable) -> bool: - ''' - Check for use of stack canary - ''' - stdout = run_command([OTOOL_CMD, '-Iv', executable]) + if content == [243, 15, 30, 250]: # endbr64 + return True + return False - ok = False - for line in stdout.splitlines(): - if '___stack_chk_fail' in line: - ok = True - return ok CHECKS = { 'ELF': [ @@ -259,17 +210,19 @@ CHECKS = { ('separate_code', check_ELF_separate_code), ], 'PE': [ + ('PIE', check_PIE), ('DYNAMIC_BASE', check_PE_DYNAMIC_BASE), ('HIGH_ENTROPY_VA', check_PE_HIGH_ENTROPY_VA), - ('NX', check_PE_NX), + ('NX', check_NX), ('RELOC_SECTION', check_PE_RELOC_SECTION) ], 'MACHO': [ - ('PIE', check_MACHO_PIE), + ('PIE', check_PIE), ('NOUNDEFS', check_MACHO_NOUNDEFS), - ('NX', check_MACHO_NX), + ('NX', check_NX), ('LAZY_BINDINGS', check_MACHO_LAZY_BINDINGS), - ('Canary', check_MACHO_Canary) + ('Canary', check_MACHO_Canary), + ('CONTROL_FLOW', check_control_flow), ] } @@ -285,24 +238,24 @@ def identify_executable(executable) -> Optional[str]: return None if __name__ == '__main__': - retval = 0 + retval: int = 0 for filename in sys.argv[1:]: try: etype = identify_executable(filename) if etype is None: - print('%s: unknown format' % filename) + print(f'{filename}: unknown format') retval = 1 continue - failed = [] + failed: List[str] = [] for (name, func) in CHECKS[etype]: if not func(filename): failed.append(name) if failed: - print('%s: failed %s' % (filename, ' '.join(failed))) + print(f'{filename}: failed {" ".join(failed)}') retval = 1 except IOError: - print('%s: cannot open' % filename) + print(f'{filename}: cannot open') retval = 1 sys.exit(retval) |