mbedtls/scripts/generate_psa_constants.py
Gilles Peskine 029b5d648d New utility program psa/psa_constant_names
Print the symbolic name corresponding to a numerical value.

Supported types: status values, algorithms, elliptic curves,
key types, key usage masks.

The program is partly generated from parsing psa/crypto.h with a few
hard-coded assumptions. This isn't ideal but it works and requires
little machinery.
2018-09-12 16:41:12 +03:00

301 lines
11 KiB
Python
Executable file

#!/usr/bin/env python
import os
import re
import sys
output_template = '''\
/* Automatically generated by generate_psa_constant.py. DO NOT EDIT. */
static const char *psa_strerror(psa_status_t status)
{
switch (status) {
%(status_cases)s
default: return NULL;
}
}
static const char *psa_ecc_curve_name(psa_ecc_curve_t curve)
{
switch (curve) {
%(ecc_curve_cases)s
default: return NULL;
}
}
static const char *psa_hash_algorithm_name(psa_algorithm_t hash_alg)
{
switch (hash_alg) {
%(hash_algorithm_cases)s
default: return NULL;
}
}
static int psa_snprint_key_type(char *buffer, size_t buffer_size,
psa_key_type_t type)
{
size_t required_size = 0;
switch (type) {
%(key_type_cases)s
default:
%(key_type_code)s{
return snprintf(buffer, buffer_size,
"0x%%08lx", (unsigned long) type);
}
break;
}
buffer[0] = 0;
return required_size;
}
static void append_padding_mode(char **buffer, size_t buffer_size,
size_t *required_size,
psa_algorithm_t padding_mode)
{
size_t n;
append(buffer, buffer_size, required_size, " | ", 3);
switch (padding_mode) {
%(padding_mode_cases)s
default:
n = snprintf(*buffer, buffer_size - *required_size,
"0x%%08lx", (unsigned long) padding_mode);
if (n < buffer_size - *required_size) *buffer += n;
*required_size += n;
break;
}
}
static int psa_snprint_algorithm(char *buffer, size_t buffer_size,
psa_algorithm_t alg)
{
size_t required_size = 0;
psa_algorithm_t padding_mode = -1;
psa_algorithm_t alg_without_padding = alg;
if (PSA_ALG_IS_CIPHER(alg) && PSA_ALG_IS_BLOCK_CIPHER(alg)) {
padding_mode = alg & PSA_ALG_BLOCK_CIPHER_PADDING_MASK;
alg_without_padding = alg & ~PSA_ALG_BLOCK_CIPHER_PADDING_MASK;
}
switch (alg_without_padding) {
%(algorithm_cases)s
default:
%(algorithm_code)s{
return snprintf(buffer, buffer_size,
"0x%%08lx", (unsigned long) alg);
}
break;
}
if (padding_mode != (psa_algorithm_t) -1) {
append_padding_mode(&buffer, buffer_size, &required_size, padding_mode);
}
buffer[0] = 0;
return required_size;
}
static int psa_snprint_key_usage(char *buffer, size_t buffer_size,
psa_key_usage_t usage)
{
size_t required_size = 0;
if (usage == 0) {
if (buffer_size > 1) {
buffer[0] = '0';
buffer[1] = 0;
} else if (buffer_size == 1) {
buffer[0] = 0;
}
return 1;
}
%(key_usage_code)s
if (usage != 0) {
if (required_size != 0) {
append(&buffer, buffer_size, &required_size, " | ", 3);
}
required_size += snprintf(buffer, buffer_size - required_size,
"0x%%08x", usage);
} else {
buffer[0] = 0;
}
return required_size;
}
/* End of automatically generated file. */
'''
key_type_from_curve_template = '''if (%(tester)s(type)) {
append_with_curve(&buffer, buffer_size, &required_size,
"%(builder)s", %(builder_length)s,
PSA_KEY_TYPE_GET_CURVE(type));
} else '''
algorithm_from_hash_template = '''if (%(tester)s(alg_without_padding)) {
append_with_hash(&buffer, buffer_size, &required_size,
"%(builder)s", %(builder_length)s,
PSA_ALG_GET_HASH(alg_without_padding));
} else '''
bit_test_template = '''\
if (%(var)s & %(flag)s) {
if (required_size != 0) {
append(&buffer, buffer_size, &required_size, " | ", 3);
}
append(&buffer, buffer_size, &required_size, "%(flag)s", %(length)d);
%(var)s ^= %(flag)s;
}\
'''
class MacroCollector:
def __init__(self):
self.statuses = set()
self.key_types = set()
self.key_types_from_curve = {}
self.ecc_curves = set()
self.algorithms = set()
self.hash_algorithms = set()
self.block_cipher_padding_modes = set()
self.algorithms_from_hash = {}
self.key_usages = set()
# "#define" followed by a macro name with either no parameters
# or a single parameter. Grab the macro name in group 1, the
# parameter name if any in group 2 and the definition in group 3.
definition_re = re.compile(r'\s*#\s*define\s+(\w+)(?:\s+|\((\w+)\)\s*)(.+)(?:/[*/])?')
def read_line(self, line):
m = re.match(self.definition_re, line)
if not m:
return
name, parameter, definition = m.groups()
if name.endswith('_FLAG') or name.endswith('MASK'):
# Macro only to build actual values
return
elif (name.startswith('PSA_ERROR_') or name == 'PSA_SUCCESS') \
and not parameter:
self.statuses.add(name)
elif name.startswith('PSA_KEY_TYPE_') and not parameter:
self.key_types.add(name)
elif name.startswith('PSA_KEY_TYPE_') and parameter == 'curve':
self.key_types_from_curve[name] = name[:13] + 'IS_' + name[13:]
elif name.startswith('PSA_ECC_CURVE_') and not parameter:
self.ecc_curves.add(name)
elif name.startswith('PSA_ALG_BLOCK_CIPHER_PAD_') and not parameter:
self.block_cipher_padding_modes.add(name)
elif name.startswith('PSA_ALG_') and not parameter:
if name in ['PSA_ALG_BLOCK_CIPHER_BASE',
'PSA_ALG_ECDSA_BASE',
'PSA_ALG_RSA_PKCS1V15_SIGN_BASE']:
# Ad hoc skipping of duplicate names for some numerical values
return
self.algorithms.add(name)
# Ad hoc detection of hash algorithms
if re.search(r'0x010000[0-9A-Fa-f]{2}', definition):
self.hash_algorithms.add(name)
elif name.startswith('PSA_ALG_') and parameter == 'hash_alg':
if name in ['PSA_ALG_DSA', 'PSA_ALG_ECDSA']:
# A naming irregularity
tester = name[:8] + 'IS_RANDOMIZED_' + name[8:]
else:
tester = name[:8] + 'IS_' + name[8:]
self.algorithms_from_hash[name] = tester
elif name.startswith('PSA_KEY_USAGE_') and not parameter:
self.key_usages.add(name)
else:
# Other macro without parameter
return
def read_file(self, header_file):
for line in header_file:
self.read_line(line)
def make_return_case(self, name):
return 'case %(name)s: return "%(name)s";' % {'name': name}
def make_append_case(self, name):
template = ('case %(name)s: '
'append(&buffer, buffer_size, &required_size, "%(name)s", %(length)d); '
'break;')
return template % {'name': name, 'length': len(name)}
def make_inner_append_case(self, name):
template = ('case %(name)s: '
'append(buffer, buffer_size, required_size, "%(name)s", %(length)d); '
'break;')
return template % {'name': name, 'length': len(name)}
def make_bit_test(self, var, flag):
return bit_test_template % {'var': var,
'flag': flag,
'length': len(flag)}
def make_status_cases(self):
return '\n '.join(map(self.make_return_case,
sorted(self.statuses)))
def make_ecc_curve_cases(self):
return '\n '.join(map(self.make_return_case,
sorted(self.ecc_curves)))
def make_key_type_cases(self):
return '\n '.join(map(self.make_append_case,
sorted(self.key_types)))
def make_key_type_from_curve_code(self, builder, tester):
return key_type_from_curve_template % {'builder': builder,
'builder_length': len(builder),
'tester': tester}
def make_key_type_code(self):
d = self.key_types_from_curve
make = self.make_key_type_from_curve_code
return '\n '.join([make(k, d[k]) for k in sorted(d.keys())])
def make_hash_algorithm_cases(self):
return '\n '.join(map(self.make_return_case,
sorted(self.hash_algorithms)))
def make_padding_mode_cases(self):
return '\n '.join(map(self.make_inner_append_case,
sorted(self.block_cipher_padding_modes)))
def make_algorithm_cases(self):
return '\n '.join(map(self.make_append_case,
sorted(self.algorithms)))
def make_algorithm_from_hash_code(self, builder, tester):
return algorithm_from_hash_template % {'builder': builder,
'builder_length': len(builder),
'tester': tester}
def make_algorithm_code(self):
d = self.algorithms_from_hash
make = self.make_algorithm_from_hash_code
return '\n '.join([make(k, d[k]) for k in sorted(d.keys())])
def make_key_usage_code(self):
return '\n'.join([self.make_bit_test('usage', bit)
for bit in sorted(self.key_usages)])
def write_file(self, output_file):
data = {}
data['status_cases'] = self.make_status_cases()
data['ecc_curve_cases'] = self.make_ecc_curve_cases()
data['key_type_cases'] = self.make_key_type_cases()
data['key_type_code'] = self.make_key_type_code()
data['hash_algorithm_cases'] = self.make_hash_algorithm_cases()
data['padding_mode_cases'] = self.make_padding_mode_cases()
data['algorithm_cases'] = self.make_algorithm_cases()
data['algorithm_code'] = self.make_algorithm_code()
data['key_usage_code'] = self.make_key_usage_code()
output_file.write(output_template % data)
def generate_psa_constants(header_file_name, output_file_name):
collector = MacroCollector()
with open(header_file_name) as header_file:
collector.read_file(header_file)
temp_file_name = output_file_name + '.tmp'
with open(temp_file_name, 'w') as output_file:
collector.write_file(output_file)
os.rename(temp_file_name, output_file_name)
if __name__ == '__main__':
if not os.path.isdir('programs') and os.path.isdir('../programs'):
os.chdir('..')
generate_psa_constants('include/psa/crypto.h',
'programs/psa/psa_constant_names_generated.c')