Merge pull request #6747 from gilles-peskine-arm/bignum-mod-random

Bignum mod random

scripts/mbedtls_dev/bignum_common.py

@@ -15,6 +15,7 @@
 # limitations under the License.
 
 from abc import abstractmethod
+import enum
 from typing import Iterator, List, Tuple, TypeVar, Any
 from itertools import chain
 
@@ -53,7 +54,7 @@ def hex_to_int(val: str) -> int:
         return 0
     return int(val, 16)
 
-def quote_str(val) -> str:
+def quote_str(val: str) -> str:
     return "\"{}\"".format(val)
 
 def bound_mpi(val: int, bits_in_limb: int) -> int:
@@ -139,7 +140,7 @@ class OperationCommon(test_data_generation.BaseTest):
     def hex_digits(self) -> int:
         return 2 * (self.limbs * self.bits_in_limb // 8)
 
-    def format_arg(self, val) -> str:
+    def format_arg(self, val: str) -> str:
         if self.input_style not in self.input_styles:
             raise ValueError("Unknown input style!")
         if self.input_style == "variable":
@@ -147,7 +148,7 @@ class OperationCommon(test_data_generation.BaseTest):
         else:
             return val.zfill(self.hex_digits)
 
-    def format_result(self, res) -> str:
+    def format_result(self, res: int) -> str:
         res_str = '{:x}'.format(res)
         return quote_str(self.format_arg(res_str))
 
@@ -245,6 +246,23 @@ class OperationCommon(test_data_generation.BaseTest):
                     )
 
 
+class ModulusRepresentation(enum.Enum):
+    """Representation selector of a modulus."""
+    # Numerical values aligned with the type mbedtls_mpi_mod_rep_selector
+    INVALID = 0
+    MONTGOMERY = 2
+    OPT_RED = 3
+
+    def symbol(self) -> str:
+        """The C symbol for this representation selector."""
+        return 'MBEDTLS_MPI_MOD_REP_' + self.name
+
+    @classmethod
+    def supported_representations(cls) -> List['ModulusRepresentation']:
+        """Return all representations that are supported in positive test cases."""
+        return [cls.MONTGOMERY, cls.OPT_RED]
+
+
 class ModOperationCommon(OperationCommon):
     #pylint: disable=abstract-method
     """Target for bignum mod_raw test case generation."""
@@ -266,6 +284,17 @@ class ModOperationCommon(OperationCommon):
     def from_montgomery(self, val: int) -> int:
         return (val * self.r_inv) % self.int_n
 
+    def convert_from_canonical(self, canonical: int,
+                               rep: ModulusRepresentation) -> int:
+        """Convert values from canonical representation to the given representation."""
+        if rep is ModulusRepresentation.MONTGOMERY:
+            return self.to_montgomery(canonical)
+        elif rep is ModulusRepresentation.OPT_RED:
+            return canonical
+        else:
+            raise ValueError('Modulus representation not supported: {}'
+                             .format(rep.name))
+
     @property
     def boundary(self) -> int:
         return self.int_n
@@ -282,6 +311,9 @@ class ModOperationCommon(OperationCommon):
     def arg_n(self) -> str:
         return self.format_arg(self.val_n)
 
+    def format_arg(self, val: str) -> str:
+        return super().format_arg(val).zfill(self.hex_digits)
+
     def arguments(self) -> List[str]:
         return [quote_str(self.arg_n)] + super().arguments()
 

scripts/mbedtls_dev/bignum_mod_raw.py

@@ -14,8 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Dict, List
+from typing import Iterator, List
 
+from . import test_case
 from . import test_data_generation
 from . import bignum_common
 from .bignum_data import ONLY_PRIME_MODULI
@@ -116,6 +117,88 @@ class BignumModRawAdd(bignum_common.ModOperationCommon,
 
 # BEGIN MERGE SLOT 6
 
+class BignumModRawConvertRep(bignum_common.ModOperationCommon,
+                             BignumModRawTarget):
+    # This is an abstract class, it's ok to have unimplemented methods.
+    #pylint: disable=abstract-method
+    """Test cases for representation conversion."""
+    symbol = ""
+    input_style = "arch_split"
+    arity = 1
+    rep = bignum_common.ModulusRepresentation.INVALID
+
+    def set_representation(self, r: bignum_common.ModulusRepresentation) -> None:
+        self.rep = r
+
+    def arguments(self) -> List[str]:
+        return ([bignum_common.quote_str(self.arg_n), self.rep.symbol(),
+                 bignum_common.quote_str(self.arg_a)] +
+                self.result())
+
+    def description(self) -> str:
+        base = super().description()
+        mod_with_rep = 'mod({})'.format(self.rep.name)
+        return base.replace('mod', mod_with_rep, 1)
+
+    @classmethod
+    def test_cases_for_values(cls, rep: bignum_common.ModulusRepresentation,
+                              n: str, a: str) -> Iterator[test_case.TestCase]:
+        """Emit test cases for the given values (if any).
+
+        This may emit no test cases if a isn't valid for the modulus n,
+        or multiple test cases if rep requires different data depending
+        on the limb size.
+        """
+        for bil in cls.limb_sizes:
+            test_object = cls(n, a, bits_in_limb=bil)
+            test_object.set_representation(rep)
+            # The class is set to having separate test cases for each limb
+            # size, because the Montgomery representation requires it.
+            # But other representations don't require it. So for other
+            # representations, emit a single test case with no dependency
+            # on the limb size.
+            if rep is not bignum_common.ModulusRepresentation.MONTGOMERY:
+                test_object.dependencies = \
+                    [dep for dep in test_object.dependencies
+                     if not dep.startswith('MBEDTLS_HAVE_INT')]
+            if test_object.is_valid:
+                yield test_object.create_test_case()
+            if rep is not bignum_common.ModulusRepresentation.MONTGOMERY:
+                # A single test case (emitted, or skipped due to invalidity)
+                # is enough, since this test case doesn't depend on the
+                # limb size.
+                break
+
+    # The parent class doesn't support non-bignum parameters. So we override
+    # test generation, in order to have the representation as a parameter.
+    @classmethod
+    def generate_function_tests(cls) -> Iterator[test_case.TestCase]:
+
+        for rep in bignum_common.ModulusRepresentation.supported_representations():
+            for n in cls.moduli:
+                for a in cls.input_values:
+                    yield from cls.test_cases_for_values(rep, n, a)
+
+class BignumModRawCanonicalToModulusRep(BignumModRawConvertRep):
+    """Test cases for mpi_mod_raw_canonical_to_modulus_rep."""
+    test_function = "mpi_mod_raw_canonical_to_modulus_rep"
+    test_name = "Rep canon->mod"
+
+    def result(self) -> List[str]:
+        return [self.format_result(self.convert_from_canonical(self.int_a, self.rep))]
+
+class BignumModRawModulusToCanonicalRep(BignumModRawConvertRep):
+    """Test cases for mpi_mod_raw_modulus_to_canonical_rep."""
+    test_function = "mpi_mod_raw_modulus_to_canonical_rep"
+    test_name = "Rep mod->canon"
+
+    @property
+    def arg_a(self) -> str:
+        return self.format_arg("{:x}".format(self.convert_from_canonical(self.int_a, self.rep)))
+
+    def result(self) -> List[str]:
+        return [self.format_result(self.int_a)]
+
 # END MERGE SLOT 6
 
 # BEGIN MERGE SLOT 7