Merge pull request #6656 from tom-cosgrove-arm/bignum_pr_6225-updated
Bignum: add mod_raw_add
diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c
index 6c694b0..2f49ea2 100644
--- a/library/bignum_mod_raw.c
+++ b/library/bignum_mod_raw.c
@@ -129,7 +129,16 @@
/* END MERGE SLOT 4 */
/* BEGIN MERGE SLOT 5 */
-
+void mbedtls_mpi_mod_raw_add( mbedtls_mpi_uint *X,
+ const mbedtls_mpi_uint *A,
+ const mbedtls_mpi_uint *B,
+ const mbedtls_mpi_mod_modulus *N )
+{
+ mbedtls_mpi_uint carry, borrow;
+ carry = mbedtls_mpi_core_add( X, A, B, N->limbs );
+ borrow = mbedtls_mpi_core_sub( X, X, N->p, N->limbs );
+ (void) mbedtls_mpi_core_add_if( X, N->p, N->limbs, (unsigned) ( carry ^ borrow ) );
+}
/* END MERGE SLOT 5 */
/* BEGIN MERGE SLOT 6 */
diff --git a/library/bignum_mod_raw.h b/library/bignum_mod_raw.h
index 05fa9d6..f6c6ebd 100644
--- a/library/bignum_mod_raw.h
+++ b/library/bignum_mod_raw.h
@@ -177,7 +177,28 @@
/* END MERGE SLOT 4 */
/* BEGIN MERGE SLOT 5 */
-
+/**
+ * \brief Perform a known-size modular addition.
+ *
+ * Calculate `A + B modulo N`.
+ *
+ * The number of limbs in each operand, and the result, is given by the
+ * modulus \p N.
+ *
+ * \p X may be aliased to \p A or \p B, or even both, but may not overlap
+ * either otherwise.
+ *
+ * \param[out] X The result of the modular addition.
+ * \param[in] A Little-endian presentation of the left operand. This
+ * must be smaller than \p N.
+ * \param[in] B Little-endian presentation of the right operand. This
+ * must be smaller than \p N.
+ * \param[in] N The address of the modulus.
+ */
+void mbedtls_mpi_mod_raw_add( mbedtls_mpi_uint *X,
+ const mbedtls_mpi_uint *A,
+ const mbedtls_mpi_uint *B,
+ const mbedtls_mpi_mod_modulus *N );
/* END MERGE SLOT 5 */
/* BEGIN MERGE SLOT 6 */
diff --git a/scripts/mbedtls_dev/bignum_mod_raw.py b/scripts/mbedtls_dev/bignum_mod_raw.py
index c271048..0bbad5d 100644
--- a/scripts/mbedtls_dev/bignum_mod_raw.py
+++ b/scripts/mbedtls_dev/bignum_mod_raw.py
@@ -61,6 +61,19 @@
# BEGIN MERGE SLOT 5
+class BignumModRawAdd(bignum_common.ModOperationCommon,
+ BignumModRawTarget):
+ """Test cases for bignum mpi_mod_raw_add()."""
+ symbol = "+"
+ test_function = "mpi_mod_raw_add"
+ test_name = "mbedtls_mpi_mod_raw_add"
+ input_style = "fixed"
+ arity = 2
+
+ def result(self) -> List[str]:
+ result = (self.int_a + self.int_b) % self.int_n
+ return [self.format_result(result)]
+
# END MERGE SLOT 5
# BEGIN MERGE SLOT 6
diff --git a/tests/suites/test_suite_bignum_mod_raw.function b/tests/suites/test_suite_bignum_mod_raw.function
index 2d9e412..00ed005 100644
--- a/tests/suites/test_suite_bignum_mod_raw.function
+++ b/tests/suites/test_suite_bignum_mod_raw.function
@@ -360,6 +360,98 @@
/* BEGIN MERGE SLOT 5 */
+/* BEGIN_CASE */
+void mpi_mod_raw_add( char * input_N,
+ char * input_A, char * input_B,
+ char * input_S )
+{
+ mbedtls_mpi_uint *A = NULL;
+ mbedtls_mpi_uint *B = NULL;
+ mbedtls_mpi_uint *S = NULL;
+ mbedtls_mpi_uint *N = NULL;
+ mbedtls_mpi_uint *X = NULL;
+ size_t A_limbs, B_limbs, N_limbs, S_limbs;
+
+ mbedtls_mpi_mod_modulus m;
+ mbedtls_mpi_mod_modulus_init( &m );
+
+ TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &A, &A_limbs, input_A ) );
+ TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &B, &B_limbs, input_B ) );
+ TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &N_limbs, input_N ) );
+ TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &S, &S_limbs, input_S ) );
+
+ /* Modulus gives the number of limbs; all inputs must have the same. */
+ size_t limbs = N_limbs;
+ size_t bytes = limbs * sizeof( *A );
+
+ TEST_EQUAL( A_limbs, limbs );
+ TEST_EQUAL( B_limbs, limbs );
+ TEST_EQUAL( S_limbs, limbs );
+
+ ASSERT_ALLOC( X, limbs );
+
+ TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
+ &m, N, limbs,
+ MBEDTLS_MPI_MOD_EXT_REP_BE,
+ MBEDTLS_MPI_MOD_REP_MONTGOMERY
+ ), 0 );
+
+ /* A + B => Correct result */
+ mbedtls_mpi_mod_raw_add( X, A, B, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+
+ /* A + B: alias X to A => Correct result */
+ memcpy( X, A, bytes );
+ mbedtls_mpi_mod_raw_add( X, X, B, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+
+ /* A + B: alias X to B => Correct result */
+ memcpy( X, B, bytes );
+ mbedtls_mpi_mod_raw_add( X, A, X, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+
+ if ( memcmp(A, B, bytes ) == 0 )
+ {
+ /* A == B: alias A and B */
+
+ /* A + A => Correct result */
+ mbedtls_mpi_mod_raw_add( X, A, A, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+
+ /* A + A: X, A, B all aliased together => Correct result */
+ memcpy( X, A, bytes );
+ mbedtls_mpi_mod_raw_add( X, X, X, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+ }
+ else
+ {
+ /* A != B: test B + A */
+
+ /* B + A => Correct result */
+ mbedtls_mpi_mod_raw_add( X, B, A, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+
+ /* B + A: alias X to A => Correct result */
+ memcpy( X, A, bytes );
+ mbedtls_mpi_mod_raw_add( X, B, X, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+
+ /* B + A: alias X to B => Correct result */
+ memcpy( X, B, bytes );
+ mbedtls_mpi_mod_raw_add( X, X, A, &m );
+ ASSERT_COMPARE( X, bytes, S, bytes );
+ }
+
+exit:
+ mbedtls_mpi_mod_modulus_free( &m );
+
+ mbedtls_free( A );
+ mbedtls_free( B );
+ mbedtls_free( S );
+ mbedtls_free( N );
+ mbedtls_free( X );
+}
+/* END_CASE */
/* END MERGE SLOT 5 */
/* BEGIN MERGE SLOT 6 */