diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c index c98a1c1cb..c0877bdec 100644 --- a/library/bignum_mod_raw.c +++ b/library/bignum_mod_raw.c @@ -120,6 +120,16 @@ void mbedtls_mpi_mod_raw_sub( mbedtls_mpi_uint *X, (void) mbedtls_mpi_core_add_if( X, N->p, N->limbs, (unsigned) c ); } +void mbedtls_mpi_mod_raw_mul( mbedtls_mpi_uint *X, + const mbedtls_mpi_uint *A, + const mbedtls_mpi_uint *B, + const mbedtls_mpi_mod_modulus *N, + mbedtls_mpi_uint *T ) +{ + mbedtls_mpi_core_montmul( X, A, B, N->limbs, N->p, N->limbs, + N->rep.mont.mm, T ); +} + /* END MERGE SLOT 2 */ /* BEGIN MERGE SLOT 3 */ diff --git a/library/bignum_mod_raw.h b/library/bignum_mod_raw.h index e6237b359..380f30bcc 100644 --- a/library/bignum_mod_raw.h +++ b/library/bignum_mod_raw.h @@ -215,6 +215,41 @@ void mbedtls_mpi_mod_raw_sub( mbedtls_mpi_uint *X, const mbedtls_mpi_uint *B, const mbedtls_mpi_mod_modulus *N ); +/** \brief Multiply two MPIs, returning the residue modulo the specified + * modulus. + * + * \note Currently handles the case when `N->int_rep` is + * MBEDTLS_MPI_MOD_REP_MONTGOMERY. + * + * The size of the operation is determined by \p N. \p A, \p B and \p X must + * all be associated with the modulus \p N and must all have the same number + * of limbs as \p N. + * + * \p X may be aliased to \p A or \p B, or even both, but may not overlap + * either otherwise. They may not alias \p N (since they must be in canonical + * form, they cannot == \p N). + * + * \param[out] X The address of the result MPI. Must have the same + * number of limbs as \p N. + * On successful completion, \p X contains the result of + * the multiplication `A * B * R^-1` mod N where + * `R = 2^(biL * N->limbs)`. + * \param[in] A The address of the first MPI. + * \param[in] B The address of the second MPI. + * \param[in] N The address of the modulus. Used to perform a modulo + * operation on the result of the multiplication. + * \param[in,out] T Temporary storage of size at least 2 * N->limbs + 1 + * limbs. Its initial content is unused and + * its final content is indeterminate. + * It must not alias or otherwise overlap any of the + * other parameters. + */ +void mbedtls_mpi_mod_raw_mul( mbedtls_mpi_uint *X, + const mbedtls_mpi_uint *A, + const mbedtls_mpi_uint *B, + const mbedtls_mpi_mod_modulus *N, + mbedtls_mpi_uint *T ); + /* END MERGE SLOT 2 */ /* BEGIN MERGE SLOT 3 */ diff --git a/scripts/mbedtls_dev/bignum_mod_raw.py b/scripts/mbedtls_dev/bignum_mod_raw.py index 6fc4c919b..296e2d2d1 100644 --- a/scripts/mbedtls_dev/bignum_mod_raw.py +++ b/scripts/mbedtls_dev/bignum_mod_raw.py @@ -50,6 +50,25 @@ class BignumModRawSub(bignum_common.ModOperationCommon, result = (self.int_a - self.int_b) % self.int_n return [self.format_result(result)] +class BignumModRawMul(bignum_common.ModOperationCommon, + BignumModRawTarget): + """Test cases for bignum mpi_mod_raw_mul().""" + symbol = "*" + test_function = "mpi_mod_raw_mul" + test_name = "mbedtls_mpi_mod_raw_mul" + input_style = "arch_split" + arity = 2 + + def arguments(self) -> List[str]: + return [self.format_result(self.to_montgomery(self.int_a)), + self.format_result(self.to_montgomery(self.int_b)), + bignum_common.quote_str(self.arg_n) + ] + self.result() + + def result(self) -> List[str]: + result = (self.int_a * self.int_b) % self.int_n + return [self.format_result(self.to_montgomery(result))] + # END MERGE SLOT 2 # BEGIN MERGE SLOT 3 diff --git a/tests/suites/test_suite_bignum_mod_raw.function b/tests/suites/test_suite_bignum_mod_raw.function index 83e1f543e..b1d1f77eb 100644 --- a/tests/suites/test_suite_bignum_mod_raw.function +++ b/tests/suites/test_suite_bignum_mod_raw.function @@ -345,6 +345,101 @@ exit: } /* END_CASE */ +/* BEGIN_CASE */ +void mpi_mod_raw_mul( char * input_A, + char * input_B, + char * input_N, + char * result ) +{ + mbedtls_mpi_uint *A = NULL; + mbedtls_mpi_uint *B = NULL; + mbedtls_mpi_uint *N = NULL; + mbedtls_mpi_uint *X = NULL; + mbedtls_mpi_uint *R = NULL; + mbedtls_mpi_uint *T = NULL; + size_t limbs_A; + size_t limbs_B; + size_t limbs_N; + size_t limbs_R; + + mbedtls_mpi_mod_modulus m; + mbedtls_mpi_mod_modulus_init( &m ); + + TEST_EQUAL( mbedtls_test_read_mpi_core( &A, &limbs_A, input_A ), 0 ); + TEST_EQUAL( mbedtls_test_read_mpi_core( &B, &limbs_B, input_B ), 0 ); + TEST_EQUAL( mbedtls_test_read_mpi_core( &N, &limbs_N, input_N ), 0 ); + TEST_EQUAL( mbedtls_test_read_mpi_core( &R, &limbs_R, result ), 0 ); + + const size_t limbs = limbs_N; + const size_t bytes = limbs * sizeof( mbedtls_mpi_uint ); + + TEST_EQUAL( limbs_A, limbs ); + TEST_EQUAL( limbs_B, limbs ); + TEST_EQUAL( limbs_R, limbs ); + + ASSERT_ALLOC( X, limbs ); + + TEST_EQUAL( mbedtls_mpi_mod_modulus_setup( + &m, N, limbs, + MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 ); + + const size_t limbs_T = limbs * 2 + 1; + ASSERT_ALLOC( T, limbs_T ); + + mbedtls_mpi_mod_raw_mul( X, A, B, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + + /* alias X to A */ + memcpy( X, A, bytes ); + mbedtls_mpi_mod_raw_mul( X, X, B, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + + /* alias X to B */ + memcpy( X, B, bytes ); + mbedtls_mpi_mod_raw_mul( X, A, X, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + + /* A == B: alias A and B */ + if( memcmp( A, B, bytes ) == 0 ) + { + mbedtls_mpi_mod_raw_mul( X, A, A, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + + /* X, A, B all aliased together */ + memcpy( X, A, bytes ); + mbedtls_mpi_mod_raw_mul( X, X, X, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + } + + /* A != B: test B * A */ + else + { + mbedtls_mpi_mod_raw_mul( X, B, A, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + + /* B * A: alias X to A */ + memcpy( X, A, bytes ); + mbedtls_mpi_mod_raw_mul( X, B, X, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + + /* B + A: alias X to B */ + memcpy( X, B, bytes ); + mbedtls_mpi_mod_raw_mul( X, X, A, &m, T ); + ASSERT_COMPARE( X, bytes, R, bytes ); + } + +exit: + mbedtls_free( A ); + mbedtls_free( B ); + mbedtls_free( X ); + mbedtls_free( R ); + mbedtls_free( T ); + + mbedtls_mpi_mod_modulus_free( &m ); + mbedtls_free( N ); +} +/* END_CASE */ + /* END MERGE SLOT 2 */ /* BEGIN MERGE SLOT 3 */