mbedtls/scripts/mbedtls_dev/bignum_common.py
Janos Follath abfca8f938 Bignum tests: make n an attribute
Having int_ variants as an attribute has the advantage of the input
being validated when the object is instantiated. In theory otherwise if
a particular int_ attribute is not accessed, then the invalid argument
is passed to the tests as it is. (This would in all likelihood detected
by the actual test cases, still, it is more robust like this.)

There are no semantic changes to the generated test cases. (The order
of appearance of 64 and 32 bit mpi_core_add_and_add_if test cases has
changed.)

Signed-off-by: Janos Follath <janos.follath@arm.com>
2022-11-21 08:56:14 +00:00

277 lines
8.8 KiB
Python

"""Common features for bignum in test generation framework."""
# Copyright The Mbed TLS Contributors
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from abc import abstractmethod
from typing import Iterator, List, Tuple, TypeVar
from . import test_case
from . import test_data_generation
T = TypeVar('T') #pylint: disable=invalid-name
def invmod(a: int, n: int) -> int:
"""Return inverse of a to modulo n.
Equivalent to pow(a, -1, n) in Python 3.8+. Implementation is equivalent
to long_invmod() in CPython.
"""
b, c = 1, 0
while n:
q, r = divmod(a, n)
a, b, c, n = n, c, b - q*c, r
# at this point a is the gcd of the original inputs
if a == 1:
return b
raise ValueError("Not invertible")
def hex_to_int(val: str) -> int:
"""Implement the syntax accepted by mbedtls_test_read_mpi().
This is a superset of what is accepted by mbedtls_test_read_mpi_core().
"""
if val in ['', '-']:
return 0
return int(val, 16)
def quote_str(val) -> str:
return "\"{}\"".format(val)
def bound_mpi(val: int, bits_in_limb: int) -> int:
"""First number exceeding number of limbs needed for given input value."""
return bound_mpi_limbs(limbs_mpi(val, bits_in_limb), bits_in_limb)
def bound_mpi_limbs(limbs: int, bits_in_limb: int) -> int:
"""First number exceeding maximum of given number of limbs."""
bits = bits_in_limb * limbs
return 1 << bits
def limbs_mpi(val: int, bits_in_limb: int) -> int:
"""Return the number of limbs required to store value."""
return (val.bit_length() + bits_in_limb - 1) // bits_in_limb
def combination_pairs(values: List[T]) -> List[Tuple[T, T]]:
"""Return all pair combinations from input values."""
return [(x, y) for x in values for y in values]
class OperationCommon(test_data_generation.BaseTest):
"""Common features for bignum binary operations.
This adds functionality common in binary operation tests.
Attributes:
symbol: Symbol to use for the operation in case description.
input_values: List of values to use as test case inputs. These are
combined to produce pairs of values.
input_cases: List of tuples containing pairs of test case inputs. This
can be used to implement specific pairs of inputs.
unique_combinations_only: Boolean to select if test case combinations
must be unique. If True, only A,B or B,A would be included as a test
case. If False, both A,B and B,A would be included.
input_style: Controls the way how test data is passed to the functions
in the generated test cases. "variable" passes them as they are
defined in the python source. "arch_split" pads the values with
zeroes depending on the architecture/limb size. If this is set,
test cases are generated for all architectures.
"""
symbol = ""
input_values = [] # type: List[str]
input_cases = [] # type: List[Tuple[str, str]]
unique_combinations_only = True
input_styles = ["variable", "arch_split"] # type: List[str]
input_style = "variable" # type: str
limb_sizes = [32, 64] # type: List[int]
def __init__(self, val_a: str, val_b: str, bits_in_limb: int = 64) -> None:
self.val_a = val_a
self.val_b = val_b
# Setting the int versions here as opposed to making them @properties
# provides earlier/more robust input validation.
self.int_a = hex_to_int(val_a)
self.int_b = hex_to_int(val_b)
if bits_in_limb not in self.limb_sizes:
raise ValueError("Invalid number of bits in limb!")
if self.input_style == "arch_split":
self.dependencies = ["MBEDTLS_HAVE_INT{:d}".format(bits_in_limb)]
self.bits_in_limb = bits_in_limb
@property
def boundary(self) -> int:
data_in = [self.int_a, self.int_b]
return max([n for n in data_in if n is not None])
@property
def limb_boundary(self) -> int:
return bound_mpi(self.boundary, self.bits_in_limb)
@property
def limbs(self) -> int:
return limbs_mpi(self.boundary, self.bits_in_limb)
@property
def hex_digits(self) -> int:
return 2 * (self.limbs * self.bits_in_limb // 8)
def format_arg(self, val) -> str:
if self.input_style not in self.input_styles:
raise ValueError("Unknown input style!")
if self.input_style == "variable":
return val
else:
return val.zfill(self.hex_digits)
def format_result(self, res) -> str:
res_str = '{:x}'.format(res)
return quote_str(self.format_arg(res_str))
@property
def arg_a(self) -> str:
return self.format_arg(self.val_a)
@property
def arg_b(self) -> str:
return self.format_arg(self.val_b)
def arguments(self) -> List[str]:
return [
quote_str(self.arg_a), quote_str(self.arg_b)
] + self.result()
def description(self) -> str:
"""Generate a description for the test case.
If not set, case_description uses the form A `symbol` B, where symbol
is used to represent the operation. Descriptions of each value are
generated to provide some context to the test case.
"""
if not self.case_description:
self.case_description = "{:x} {} {:x}".format(
self.int_a, self.symbol, self.int_b
)
return super().description()
@abstractmethod
def result(self) -> List[str]:
"""Get the result of the operation.
This could be calculated during initialization and stored as `_result`
and then returned, or calculated when the method is called.
"""
raise NotImplementedError
@classmethod
def get_value_pairs(cls) -> Iterator[Tuple[str, str]]:
"""Generator to yield pairs of inputs.
Combinations are first generated from all input values, and then
specific cases provided.
"""
if cls.unique_combinations_only:
yield from combination_pairs(cls.input_values)
else:
yield from (
(a, b)
for a in cls.input_values
for b in cls.input_values
)
yield from cls.input_cases
@classmethod
def generate_function_tests(cls) -> Iterator[test_case.TestCase]:
if cls.input_style not in cls.input_styles:
raise ValueError("Unknown input style!")
for a_value, b_value in cls.get_value_pairs():
if cls.input_style == "arch_split":
for bil in cls.limb_sizes:
yield cls(a_value, b_value,
bits_in_limb=bil).create_test_case()
else:
yield cls(a_value, b_value).create_test_case()
class ModOperationCommon(OperationCommon):
#pylint: disable=abstract-method
"""Target for bignum mod_raw test case generation."""
def __init__(self, val_n: str, val_a: str, val_b: str = "0",
bits_in_limb: int = 64) -> None:
super().__init__(val_a=val_a, val_b=val_b, bits_in_limb=bits_in_limb)
self.val_n = val_n
# Setting the int versions here as opposed to making them @properties
# provides earlier/more robust input validation.
self.int_n = hex_to_int(val_n)
@property
def boundary(self) -> int:
data_in = [self.int_a, self.int_b, self.int_n]
return max([n for n in data_in if n is not None])
@property
def arg_n(self) -> str:
return self.format_arg(self.val_n)
@property
def r(self) -> int: # pylint: disable=invalid-name
l = limbs_mpi(self.int_n, self.bits_in_limb)
return bound_mpi_limbs(l, self.bits_in_limb)
@property
def r_inv(self) -> int:
return invmod(self.r, self.int_n)
@property
def r2(self) -> int: # pylint: disable=invalid-name
return pow(self.r, 2)
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