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Diffstat (limited to 'scripts/config.py')
| -rwxr-xr-x | scripts/config.py | 603 |
1 files changed, 603 insertions, 0 deletions
diff --git a/scripts/config.py b/scripts/config.py new file mode 100755 index 00000000000..c53f9e7fe20 --- /dev/null +++ b/scripts/config.py @@ -0,0 +1,603 @@ +#!/usr/bin/env python3 + +"""Mbed TLS configuration file manipulation library and tool + +Basic usage, to read the Mbed TLS configuration: + config = ConfigFile() + if 'MBEDTLS_RSA_C' in config: print('RSA is enabled') +""" + +# Note that as long as Mbed TLS 2.28 LTS is maintained, the version of +# this script in the mbedtls-2.28 branch must remain compatible with +# Python 3.4. The version in development may only use more recent features +# in parts that are not backported to 2.28. + +## Copyright The Mbed TLS Contributors +## SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +## + +import os +import re + +class Setting: + """Representation of one Mbed TLS mbedtls_config.h setting. + + Fields: + * name: the symbol name ('MBEDTLS_xxx'). + * value: the value of the macro. The empty string for a plain #define + with no value. + * active: True if name is defined, False if a #define for name is + present in mbedtls_config.h but commented out. + * section: the name of the section that contains this symbol. + """ + # pylint: disable=too-few-public-methods + def __init__(self, active, name, value='', section=None): + self.active = active + self.name = name + self.value = value + self.section = section + +class Config: + """Representation of the Mbed TLS configuration. + + In the documentation of this class, a symbol is said to be *active* + if there is a #define for it that is not commented out, and *known* + if there is a #define for it whether commented out or not. + + This class supports the following protocols: + * `name in config` is `True` if the symbol `name` is active, `False` + otherwise (whether `name` is inactive or not known). + * `config[name]` is the value of the macro `name`. If `name` is inactive, + raise `KeyError` (even if `name` is known). + * `config[name] = value` sets the value associated to `name`. `name` + must be known, but does not need to be set. This does not cause + name to become set. + """ + + def __init__(self): + self.settings = {} + + def __contains__(self, name): + """True if the given symbol is active (i.e. set). + + False if the given symbol is not set, even if a definition + is present but commented out. + """ + return name in self.settings and self.settings[name].active + + def all(self, *names): + """True if all the elements of names are active (i.e. set).""" + return all(self.__contains__(name) for name in names) + + def any(self, *names): + """True if at least one symbol in names are active (i.e. set).""" + return any(self.__contains__(name) for name in names) + + def known(self, name): + """True if a #define for name is present, whether it's commented out or not.""" + return name in self.settings + + def __getitem__(self, name): + """Get the value of name, i.e. what the preprocessor symbol expands to. + + If name is not known, raise KeyError. name does not need to be active. + """ + return self.settings[name].value + + def get(self, name, default=None): + """Get the value of name. If name is inactive (not set), return default. + + If a #define for name is present and not commented out, return + its expansion, even if this is the empty string. + + If a #define for name is present but commented out, return default. + """ + if name in self.settings: + return self.settings[name].value + else: + return default + + def __setitem__(self, name, value): + """If name is known, set its value. + + If name is not known, raise KeyError. + """ + self.settings[name].value = value + + def set(self, name, value=None): + """Set name to the given value and make it active. + + If value is None and name is already known, don't change its value. + If value is None and name is not known, set its value to the empty + string. + """ + if name in self.settings: + if value is not None: + self.settings[name].value = value + self.settings[name].active = True + else: + self.settings[name] = Setting(True, name, value=value) + + def unset(self, name): + """Make name unset (inactive). + + name remains known if it was known before. + """ + if name not in self.settings: + return + self.settings[name].active = False + + def adapt(self, adapter): + """Run adapter on each known symbol and (de)activate it accordingly. + + `adapter` must be a function that returns a boolean. It is called as + `adapter(name, active, section)` for each setting, where `active` is + `True` if `name` is set and `False` if `name` is known but unset, + and `section` is the name of the section containing `name`. If + `adapter` returns `True`, then set `name` (i.e. make it active), + otherwise unset `name` (i.e. make it known but inactive). + """ + for setting in self.settings.values(): + setting.active = adapter(setting.name, setting.active, + setting.section) + + def change_matching(self, regexs, enable): + """Change all symbols matching one of the regexs to the desired state.""" + if not regexs: + return + regex = re.compile('|'.join(regexs)) + for setting in self.settings.values(): + if regex.search(setting.name): + setting.active = enable + +def is_full_section(section): + """Is this section affected by "config.py full" and friends?""" + return section.endswith('support') or section.endswith('modules') + +def realfull_adapter(_name, active, section): + """Activate all symbols found in the global and boolean feature sections. + + This is intended for building the documentation, including the + documentation of settings that are activated by defining an optional + preprocessor macro. + + Do not activate definitions in the section containing symbols that are + supposed to be defined and documented in their own module. + """ + if section == 'Module configuration options': + return active + return True + +# The goal of the full configuration is to have everything that can be tested +# together. This includes deprecated or insecure options. It excludes: +# * Options that require additional build dependencies or unusual hardware. +# * Options that make testing less effective. +# * Options that are incompatible with other options, or more generally that +# interact with other parts of the code in such a way that a bulk enabling +# is not a good way to test them. +# * Options that remove features. +EXCLUDE_FROM_FULL = frozenset([ + #pylint: disable=line-too-long + 'MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH', # interacts with CTR_DRBG_128_BIT_KEY + 'MBEDTLS_AES_USE_HARDWARE_ONLY', # hardware dependency + 'MBEDTLS_BLOCK_CIPHER_NO_DECRYPT', # incompatible with ECB in PSA, CBC/XTS/NIST_KW/DES + 'MBEDTLS_CTR_DRBG_USE_128_BIT_KEY', # interacts with ENTROPY_FORCE_SHA256 + 'MBEDTLS_DEPRECATED_REMOVED', # conflicts with deprecated options + 'MBEDTLS_DEPRECATED_WARNING', # conflicts with deprecated options + 'MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED', # influences the use of ECDH in TLS + 'MBEDTLS_ECP_NO_FALLBACK', # removes internal ECP implementation + 'MBEDTLS_ECP_WITH_MPI_UINT', # disables the default ECP and is experimental + 'MBEDTLS_ENTROPY_FORCE_SHA256', # interacts with CTR_DRBG_128_BIT_KEY + 'MBEDTLS_HAVE_SSE2', # hardware dependency + 'MBEDTLS_MEMORY_BACKTRACE', # depends on MEMORY_BUFFER_ALLOC_C + 'MBEDTLS_MEMORY_BUFFER_ALLOC_C', # makes sanitizers (e.g. ASan) less effective + 'MBEDTLS_MEMORY_DEBUG', # depends on MEMORY_BUFFER_ALLOC_C + 'MBEDTLS_NO_64BIT_MULTIPLICATION', # influences anything that uses bignum + 'MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES', # removes a feature + 'MBEDTLS_NO_PLATFORM_ENTROPY', # removes a feature + 'MBEDTLS_NO_UDBL_DIVISION', # influences anything that uses bignum + 'MBEDTLS_PSA_P256M_DRIVER_ENABLED', # influences SECP256R1 KeyGen/ECDH/ECDSA + 'MBEDTLS_PLATFORM_NO_STD_FUNCTIONS', # removes a feature + 'MBEDTLS_PSA_ASSUME_EXCLUSIVE_BUFFERS', # removes a feature + 'MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG', # behavior change + build dependency + 'MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER', # incompatible with USE_PSA_CRYPTO + 'MBEDTLS_PSA_CRYPTO_SPM', # platform dependency (PSA SPM) + 'MBEDTLS_PSA_INJECT_ENTROPY', # conflicts with platform entropy sources + 'MBEDTLS_RSA_NO_CRT', # influences the use of RSA in X.509 and TLS + 'MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY', # interacts with *_USE_A64_CRYPTO_IF_PRESENT + 'MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY', # interacts with *_USE_ARMV8_A_CRYPTO_IF_PRESENT + 'MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY', # interacts with *_USE_A64_CRYPTO_IF_PRESENT + 'MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT', # setting *_USE_ARMV8_A_CRYPTO is sufficient + 'MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN', # build dependency (clang+memsan) + 'MBEDTLS_TEST_CONSTANT_FLOW_VALGRIND', # build dependency (valgrind headers) + 'MBEDTLS_X509_REMOVE_INFO', # removes a feature +]) + +def is_seamless_alt(name): + """Whether the xxx_ALT symbol should be included in the full configuration. + + Include alternative implementations of platform functions, which are + configurable function pointers that default to the built-in function. + This way we test that the function pointers exist and build correctly + without changing the behavior, and tests can verify that the function + pointers are used by modifying those pointers. + + Exclude alternative implementations of library functions since they require + an implementation of the relevant functions and an xxx_alt.h header. + """ + if name in ( + 'MBEDTLS_PLATFORM_GMTIME_R_ALT', + 'MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT', + 'MBEDTLS_PLATFORM_MS_TIME_ALT', + 'MBEDTLS_PLATFORM_ZEROIZE_ALT', + ): + # Similar to non-platform xxx_ALT, requires platform_alt.h + return False + return name.startswith('MBEDTLS_PLATFORM_') + +def include_in_full(name): + """Rules for symbols in the "full" configuration.""" + if name in EXCLUDE_FROM_FULL: + return False + if name.endswith('_ALT'): + return is_seamless_alt(name) + return True + +def full_adapter(name, active, section): + """Config adapter for "full".""" + if not is_full_section(section): + return active + return include_in_full(name) + +# The baremetal configuration excludes options that require a library or +# operating system feature that is typically not present on bare metal +# systems. Features that are excluded from "full" won't be in "baremetal" +# either (unless explicitly turned on in baremetal_adapter) so they don't +# need to be repeated here. +EXCLUDE_FROM_BAREMETAL = frozenset([ + #pylint: disable=line-too-long + 'MBEDTLS_ENTROPY_NV_SEED', # requires a filesystem and FS_IO or alternate NV seed hooks + 'MBEDTLS_FS_IO', # requires a filesystem + 'MBEDTLS_HAVE_TIME', # requires a clock + 'MBEDTLS_HAVE_TIME_DATE', # requires a clock + 'MBEDTLS_NET_C', # requires POSIX-like networking + 'MBEDTLS_PLATFORM_FPRINTF_ALT', # requires FILE* from stdio.h + 'MBEDTLS_PLATFORM_NV_SEED_ALT', # requires a filesystem and ENTROPY_NV_SEED + 'MBEDTLS_PLATFORM_TIME_ALT', # requires a clock and HAVE_TIME + 'MBEDTLS_PSA_CRYPTO_SE_C', # requires a filesystem and PSA_CRYPTO_STORAGE_C + 'MBEDTLS_PSA_CRYPTO_STORAGE_C', # requires a filesystem + 'MBEDTLS_PSA_ITS_FILE_C', # requires a filesystem + 'MBEDTLS_THREADING_C', # requires a threading interface + 'MBEDTLS_THREADING_PTHREAD', # requires pthread + 'MBEDTLS_TIMING_C', # requires a clock + 'MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT', # requires an OS for runtime-detection + 'MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT', # requires an OS for runtime-detection + 'MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT', # requires an OS for runtime-detection +]) + +def keep_in_baremetal(name): + """Rules for symbols in the "baremetal" configuration.""" + if name in EXCLUDE_FROM_BAREMETAL: + return False + return True + +def baremetal_adapter(name, active, section): + """Config adapter for "baremetal".""" + if not is_full_section(section): + return active + if name == 'MBEDTLS_NO_PLATFORM_ENTROPY': + # No OS-provided entropy source + return True + return include_in_full(name) and keep_in_baremetal(name) + +# This set contains options that are mostly for debugging or test purposes, +# and therefore should be excluded when doing code size measurements. +# Options that are their own module (such as MBEDTLS_ERROR_C) are not listed +# and therefore will be included when doing code size measurements. +EXCLUDE_FOR_SIZE = frozenset([ + 'MBEDTLS_DEBUG_C', # large code size increase in TLS + 'MBEDTLS_SELF_TEST', # increases the size of many modules + 'MBEDTLS_TEST_HOOKS', # only useful with the hosted test framework, increases code size +]) + +def baremetal_size_adapter(name, active, section): + if name in EXCLUDE_FOR_SIZE: + return False + return baremetal_adapter(name, active, section) + +def include_in_crypto(name): + """Rules for symbols in a crypto configuration.""" + if name.startswith('MBEDTLS_X509_') or \ + name.startswith('MBEDTLS_SSL_') or \ + name.startswith('MBEDTLS_KEY_EXCHANGE_'): + return False + if name in [ + 'MBEDTLS_DEBUG_C', # part of libmbedtls + 'MBEDTLS_NET_C', # part of libmbedtls + 'MBEDTLS_PKCS7_C', # part of libmbedx509 + ]: + return False + return True + +def crypto_adapter(adapter): + """Modify an adapter to disable non-crypto symbols. + + ``crypto_adapter(adapter)(name, active, section)`` is like + ``adapter(name, active, section)``, but unsets all X.509 and TLS symbols. + """ + def continuation(name, active, section): + if not include_in_crypto(name): + return False + if adapter is None: + return active + return adapter(name, active, section) + return continuation + +DEPRECATED = frozenset([ + 'MBEDTLS_PSA_CRYPTO_SE_C', +]) +def no_deprecated_adapter(adapter): + """Modify an adapter to disable deprecated symbols. + + ``no_deprecated_adapter(adapter)(name, active, section)`` is like + ``adapter(name, active, section)``, but unsets all deprecated symbols + and sets ``MBEDTLS_DEPRECATED_REMOVED``. + """ + def continuation(name, active, section): + if name == 'MBEDTLS_DEPRECATED_REMOVED': + return True + if name in DEPRECATED: + return False + if adapter is None: + return active + return adapter(name, active, section) + return continuation + +def no_platform_adapter(adapter): + """Modify an adapter to disable platform symbols. + + ``no_platform_adapter(adapter)(name, active, section)`` is like + ``adapter(name, active, section)``, but unsets all platform symbols other + ``than MBEDTLS_PLATFORM_C. + """ + def continuation(name, active, section): + # Allow MBEDTLS_PLATFORM_C but remove all other platform symbols. + if name.startswith('MBEDTLS_PLATFORM_') and name != 'MBEDTLS_PLATFORM_C': + return False + if adapter is None: + return active + return adapter(name, active, section) + return continuation + +class ConfigFile(Config): + """Representation of the Mbed TLS configuration read for a file. + + See the documentation of the `Config` class for methods to query + and modify the configuration. + """ + + _path_in_tree = 'include/mbedtls/mbedtls_config.h' + default_path = [_path_in_tree, + os.path.join(os.path.dirname(__file__), + os.pardir, + _path_in_tree), + os.path.join(os.path.dirname(os.path.abspath(os.path.dirname(__file__))), + _path_in_tree)] + + def __init__(self, filename=None): + """Read the Mbed TLS configuration file.""" + if filename is None: + for candidate in self.default_path: + if os.path.lexists(candidate): + filename = candidate + break + else: + raise Exception('Mbed TLS configuration file not found', + self.default_path) + super().__init__() + self.filename = filename + self.current_section = 'header' + with open(filename, 'r', encoding='utf-8') as file: + self.templates = [self._parse_line(line) for line in file] + self.current_section = None + + def set(self, name, value=None): + if name not in self.settings: + self.templates.append((name, '', '#define ' + name + ' ')) + super().set(name, value) + + _define_line_regexp = (r'(?P<indentation>\s*)' + + r'(?P<commented_out>(//\s*)?)' + + r'(?P<define>#\s*define\s+)' + + r'(?P<name>\w+)' + + r'(?P<arguments>(?:\((?:\w|\s|,)*\))?)' + + r'(?P<separator>\s*)' + + r'(?P<value>.*)') + _section_line_regexp = (r'\s*/?\*+\s*[\\@]name\s+SECTION:\s*' + + r'(?P<section>.*)[ */]*') + _config_line_regexp = re.compile(r'|'.join([_define_line_regexp, + _section_line_regexp])) + def _parse_line(self, line): + """Parse a line in mbedtls_config.h and return the corresponding template.""" + line = line.rstrip('\r\n') + m = re.match(self._config_line_regexp, line) + if m is None: + return line + elif m.group('section'): + self.current_section = m.group('section') + return line + else: + active = not m.group('commented_out') + name = m.group('name') + value = m.group('value') + template = (name, + m.group('indentation'), + m.group('define') + name + + m.group('arguments') + m.group('separator')) + self.settings[name] = Setting(active, name, value, + self.current_section) + return template + + def _format_template(self, name, indent, middle): + """Build a line for mbedtls_config.h for the given setting. + + The line has the form "<indent>#define <name> <value>" + where <middle> is "#define <name> ". + """ + setting = self.settings[name] + value = setting.value + if value is None: + value = '' + # Normally the whitespace to separate the symbol name from the + # value is part of middle, and there's no whitespace for a symbol + # with no value. But if a symbol has been changed from having a + # value to not having one, the whitespace is wrong, so fix it. + if value: + if middle[-1] not in '\t ': + middle += ' ' + else: + middle = middle.rstrip() + return ''.join([indent, + '' if setting.active else '//', + middle, + value]).rstrip() + + def write_to_stream(self, output): + """Write the whole configuration to output.""" + for template in self.templates: + if isinstance(template, str): + line = template + else: + line = self._format_template(*template) + output.write(line + '\n') + + def write(self, filename=None): + """Write the whole configuration to the file it was read from. + + If filename is specified, write to this file instead. + """ + if filename is None: + filename = self.filename + with open(filename, 'w', encoding='utf-8') as output: + self.write_to_stream(output) + +if __name__ == '__main__': + def main(): + """Command line mbedtls_config.h manipulation tool.""" + parser = argparse.ArgumentParser(description=""" + Mbed TLS configuration file manipulation tool. + """) + parser.add_argument('--file', '-f', + help="""File to read (and modify if requested). + Default: {}. + """.format(ConfigFile.default_path)) + parser.add_argument('--force', '-o', + action='store_true', + help="""For the set command, if SYMBOL is not + present, add a definition for it.""") + parser.add_argument('--write', '-w', metavar='FILE', + help="""File to write to instead of the input file.""") + subparsers = parser.add_subparsers(dest='command', + title='Commands') + parser_get = subparsers.add_parser('get', + help="""Find the value of SYMBOL + and print it. Exit with + status 0 if a #define for SYMBOL is + found, 1 otherwise. + """) + parser_get.add_argument('symbol', metavar='SYMBOL') + parser_set = subparsers.add_parser('set', + help="""Set SYMBOL to VALUE. + If VALUE is omitted, just uncomment + the #define for SYMBOL. + Error out of a line defining + SYMBOL (commented or not) is not + found, unless --force is passed. + """) + parser_set.add_argument('symbol', metavar='SYMBOL') + parser_set.add_argument('value', metavar='VALUE', nargs='?', + default='') + parser_set_all = subparsers.add_parser('set-all', + help="""Uncomment all #define + whose name contains a match for + REGEX.""") + parser_set_all.add_argument('regexs', metavar='REGEX', nargs='*') + parser_unset = subparsers.add_parser('unset', + help="""Comment out the #define + for SYMBOL. Do nothing if none + is present.""") + parser_unset.add_argument('symbol', metavar='SYMBOL') + parser_unset_all = subparsers.add_parser('unset-all', + help="""Comment out all #define + whose name contains a match for + REGEX.""") + parser_unset_all.add_argument('regexs', metavar='REGEX', nargs='*') + + def add_adapter(name, function, description): + subparser = subparsers.add_parser(name, help=description) + subparser.set_defaults(adapter=function) + add_adapter('baremetal', baremetal_adapter, + """Like full, but exclude features that require platform + features such as file input-output.""") + add_adapter('baremetal_size', baremetal_size_adapter, + """Like baremetal, but exclude debugging features. + Useful for code size measurements.""") + add_adapter('full', full_adapter, + """Uncomment most features. + Exclude alternative implementations and platform support + options, as well as some options that are awkward to test. + """) + add_adapter('full_no_deprecated', no_deprecated_adapter(full_adapter), + """Uncomment most non-deprecated features. + Like "full", but without deprecated features. + """) + add_adapter('full_no_platform', no_platform_adapter(full_adapter), + """Uncomment most non-platform features. + Like "full", but without platform features. + """) + add_adapter('realfull', realfull_adapter, + """Uncomment all boolean #defines. + Suitable for generating documentation, but not for building.""") + add_adapter('crypto', crypto_adapter(None), + """Only include crypto features. Exclude X.509 and TLS.""") + add_adapter('crypto_baremetal', crypto_adapter(baremetal_adapter), + """Like baremetal, but with only crypto features, + excluding X.509 and TLS.""") + add_adapter('crypto_full', crypto_adapter(full_adapter), + """Like full, but with only crypto features, + excluding X.509 and TLS.""") + + args = parser.parse_args() + config = ConfigFile(args.file) + if args.command is None: + parser.print_help() + return 1 + elif args.command == 'get': + if args.symbol in config: + value = config[args.symbol] + if value: + sys.stdout.write(value + '\n') + return 0 if args.symbol in config else 1 + elif args.command == 'set': + if not args.force and args.symbol not in config.settings: + sys.stderr.write("A #define for the symbol {} " + "was not found in {}\n" + .format(args.symbol, config.filename)) + return 1 + config.set(args.symbol, value=args.value) + elif args.command == 'set-all': + config.change_matching(args.regexs, True) + elif args.command == 'unset': + config.unset(args.symbol) + elif args.command == 'unset-all': + config.change_matching(args.regexs, False) + else: + config.adapt(args.adapter) + config.write(args.write) + return 0 + + # Import modules only used by main only if main is defined and called. + # pylint: disable=wrong-import-position + import argparse + import sys + sys.exit(main()) |