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Document and test aliasing of the bignums given to mbedtls_mpi_core_mla()

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Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
This commit is contained in:
Tom Cosgrove 2022-09-20 13:33:40 +01:00
parent ea45c1d2d4
commit b0b77e1b13
2 changed files with 11 additions and 0 deletions
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3
library/bignum_core.h
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@ -214,6 +214,9 @@ mbedtls_mpi_uint mbedtls_mpi_core_sub( mbedtls_mpi_uint *X,
/**
* \brief Perform a fixed-size multiply accumulate operation: X += b * A
*
* \p X may be aliased to \p A (when \p X_limbs == \p A_limbs), but may not
* otherwise overlap.
*
* \param[in,out] X The pointer to the (little-endian) array
* representing the bignum to accumulate onto.
* \param X_limbs The number of limbs of \p X. This must be

8
tests/suites/test_suite_mpi.function
View File

@ -2008,6 +2008,14 @@ void mpi_core_mla( char * input_A, char * input_B, char * input_S,
/* 1b) A += B * s => we should get the correct result */
ASSERT_COMPARE( a, bytes, x, bytes );
if ( A.n == B.n && memcmp( A.p, B.p, bytes ) == 0 )
{
/* Check when A and B are aliased */
memcpy( a, A.p, A.n * sizeof(mbedtls_mpi_uint) );
TEST_EQUAL( mbedtls_mpi_core_mla( a, limbs, a, limbs, *S.p ), *cy->p );
ASSERT_COMPARE( a, bytes, x, bytes );
}
exit:
mbedtls_free( a );
mbedtls_free( x );