From eb591ff94dcff3a7e06b17ebe5d6b81b52d788d4 Mon Sep 17 00:00:00 2001
From: Gabor Mezei <gabor.mezei@arm.com>
Date: Wed, 8 Mar 2023 14:06:04 +0100
Subject: [PATCH] Add test generation for ecp_mod_p256_raw

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
---
 scripts/mbedtls_dev/ecp.py           | 73 ++++++++++++++++++++++++++++
 tests/suites/test_suite_ecp.function | 43 ++++++++++++++++
 2 files changed, 116 insertions(+)

diff --git a/scripts/mbedtls_dev/ecp.py b/scripts/mbedtls_dev/ecp.py
index 354b234163..f448925abe 100644
--- a/scripts/mbedtls_dev/ecp.py
+++ b/scripts/mbedtls_dev/ecp.py
@@ -145,6 +145,79 @@ class EcpP224R1Raw(bignum_common.ModOperationCommon,
         return True
 
 
+class EcpP256R1Raw(bignum_common.ModOperationCommon,
+                   EcpTarget):
+    """Test cases for ecp quasi_reduction()."""
+    symbol = "-"
+    test_function = "ecp_mod_p256_raw"
+    test_name = "ecp_mod_p256_raw"
+    input_style = "fixed"
+    arity = 1
+
+    moduli = ["ffffffff00000001000000000000000000000000ffffffffffffffffffffffff"] # type: List[str]
+
+    input_values = [
+        "0", "1",
+
+        # Modulus - 1
+        "ffffffff00000001000000000000000000000000fffffffffffffffffffffffe",
+
+        # Maximum canonical P256 multiplication result
+        ("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
+         "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+
+        # Generate an overflow during reduction
+        ("0000000000000000000000010000000000000000000000000000000000000000"
+         "00000000000000000000000000000000000000000000000000000000ffffffff"),
+
+        # Generate an underflow during reduction
+        ("0000000000000000000000000000000000000000000000000000000000000010"
+         "ffffffff00000000000000000000000000000000000000000000000000000000"),
+
+        # Generate an overflow during carry reduction
+        ("aaaaaaaa00000000000000000000000000000000000000000000000000000000"
+         "00000000000000000000000000000000aaaaaaacaaaaaaaaaaaaaaaa00000000"),
+
+        # Generate an underflow during carry reduction
+        ("000000000000000000000001ffffffff00000000000000000000000000000000"
+         "0000000000000000000000000000000000000002000000020000000100000002"),
+
+        # First 8 number generated by random.getrandbits(512) - seed(2,2)
+        ("4067c3584ee207f8da94e3e8ab73738fcf1822ffbc6887782b491044d5e34124"
+         "5c6e433715ba2bdd177219d30e7a269fd95bafc8f2a4d27bdcf4bb99f4bea973"),
+        ("82523e86feac7eb7dc38f519b91751dacdbd47d364be8049a372db8f6e405d93"
+         "ffed9235288bc781ae66267594c9c9500925e4749b575bd13653f8dd9b1f282e"),
+        ("e8624fab5186ee32ee8d7ee9770348a05d300cb90706a045defc044a09325626"
+         "e6b58de744ab6cce80877b6f71e1f6d2ef8acd128b4f2fc15f3f57ebf30b94fa"),
+        ("829a48d422fe99a22c70501e533c91352d3d854e061b90303b08c6e33c729578"
+         "2d6c797f8f7d9b782a1be9cd8697bbd0e2520e33e44c50556c71c4a66148a86f"),
+        ("e89204e2e8168561867e5e15bc01bfce6a27e0dfcbf8754472154e76e4c11ab2"
+         "fec3f6b32e8d4b8a8f54f8ceacaab39e83844b40ffa9b9f15c14bc4a829e07b0"),
+        ("bd143fa9b714210c665d7435c1066932f4767f26294365b2721dea3bf63f23d0"
+         "dbe53fcafb2147df5ca495fa5a91c89b97eeab64ca2ce6bc5d3fd983c34c769f"),
+        ("74667bffe202849da9643a295a9ac6decbd4d3e2d4dec9ef83f0be4e80371eb9"
+         "7f81375eecc1cb6347733e847d718d733ff98ff387c56473a7a83ee0761ebfd2"),
+        ("d08f1bb2531d6460f0caeef038c89b38a8acb5137c9260dc74e088a9b9492f25"
+         "8ebdbfe3eb9ac688b9d39cca91551e8259cc60b17604e4b4e73695c3e652c71a"),
+
+        # Next 2 number generated by random.getrandbits(256)
+        "c5e2486c44a4a8f69dc8db48e86ec9c6e06f291b2a838af8d5c44a4eb3172062",
+        "d4c0dca8b4c9e755cc9c3adcf515a8234da4daeb4f3f87777ad1f45ae9500ec9"
+    ]
+
+    @property
+    def arg_a(self) -> str:
+        return super().format_arg('{:x}'.format(self.int_a)).zfill(2 * self.hex_digits)
+
+    def result(self) -> List[str]:
+        result = self.int_a % self.int_n
+        return [self.format_result(result)]
+
+    @property
+    def is_valid(self) -> bool:
+        return True
+
+
 class EcpP521R1Raw(bignum_common.ModOperationCommon,
                    EcpTarget):
     """Test cases for ecp quasi_reduction()."""
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 333435a4da..ecb35464a8 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1387,6 +1387,49 @@ exit:
 }
 /* END_CASE */
 
+/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */
+void ecp_mod_p256_raw(char *input_N,
+                      char *input_X,
+                      char *result)
+{
+    mbedtls_mpi_uint *X = NULL;
+    mbedtls_mpi_uint *N = NULL;
+    mbedtls_mpi_uint *res = NULL;
+    size_t limbs_X;
+    size_t limbs_N;
+    size_t limbs_res;
+
+    mbedtls_mpi_mod_modulus m;
+    mbedtls_mpi_mod_modulus_init(&m);
+
+    TEST_EQUAL(mbedtls_test_read_mpi_core(&X,   &limbs_X,   input_X), 0);
+    TEST_EQUAL(mbedtls_test_read_mpi_core(&N,   &limbs_N,   input_N), 0);
+    TEST_EQUAL(mbedtls_test_read_mpi_core(&res, &limbs_res, result),  0);
+
+    size_t limbs = limbs_N;
+    size_t bytes = limbs * sizeof(mbedtls_mpi_uint);
+
+    TEST_EQUAL(limbs_X, 2 * limbs);
+    TEST_EQUAL(limbs_res, limbs);
+
+    TEST_EQUAL(mbedtls_mpi_mod_modulus_setup(
+                   &m, N, limbs,
+                   MBEDTLS_MPI_MOD_REP_MONTGOMERY), 0);
+
+    TEST_EQUAL(mbedtls_ecp_mod_p256_raw(X, limbs_X), 0);
+    TEST_LE_U(mbedtls_mpi_core_bitlen(X, limbs_X), 256);
+    mbedtls_mpi_mod_raw_fix_quasi_reduction(X, &m);
+    ASSERT_COMPARE(X, bytes, res, bytes);
+
+exit:
+    mbedtls_free(X);
+    mbedtls_free(res);
+
+    mbedtls_mpi_mod_modulus_free(&m);
+    mbedtls_free(N);
+}
+/* END_CASE */
+
 /* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */
 void ecp_mod_p521_raw(char *input_N,
                       char *input_X,