bignum_mod: Refactored `mbedtls_mpi_mod_read/write()`
This patch adjusts the I/O methods and the tests.
Documentation has also been updated to be more clear.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/library/bignum_mod.c b/library/bignum_mod.c
index 770e633..c10fb2e 100644
--- a/library/bignum_mod.c
+++ b/library/bignum_mod.c
@@ -210,8 +210,8 @@
/* BEGIN MERGE SLOT 7 */
int mbedtls_mpi_mod_read( mbedtls_mpi_mod_residue *r,
- mbedtls_mpi_mod_modulus *m,
- unsigned char *buf,
+ const mbedtls_mpi_mod_modulus *m,
+ const unsigned char *buf,
size_t buflen )
{
int ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
@@ -219,7 +219,7 @@
if ( r == NULL || m == NULL )
goto cleanup;
- if ( r->p == NULL || m->p == NULL || r->limbs > m->limbs ||\
+ if ( r->p == NULL || m->p == NULL || r->limbs > m->limbs ||
r->limbs == 0 || m->limbs == 0 )
goto cleanup;
@@ -228,6 +228,8 @@
if( ret != 0 )
goto cleanup;
+ r->limbs = m->limbs;
+
if (m->int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY)
ret = mbedtls_mpi_mod_raw_to_mont_rep(r->p, m);
@@ -235,8 +237,8 @@
return ( ret );
}
-int mbedtls_mpi_mod_write( mbedtls_mpi_mod_residue *r,
- mbedtls_mpi_mod_modulus *m,
+int mbedtls_mpi_mod_write( const mbedtls_mpi_mod_residue *r,
+ const mbedtls_mpi_mod_modulus *m,
unsigned char *buf,
size_t buflen )
{
@@ -245,7 +247,7 @@
if ( r == NULL || m == NULL )
goto cleanup;
- if ( r->p == NULL || m->p == NULL || r->limbs > m->limbs ||\
+ if ( r->p == NULL || m->p == NULL || r->limbs > m->limbs ||
r->limbs == 0 || m->limbs == 0 )
goto cleanup;
diff --git a/library/bignum_mod.h b/library/bignum_mod.h
index 4a01dfc..f0ce3c4 100644
--- a/library/bignum_mod.h
+++ b/library/bignum_mod.h
@@ -177,8 +177,9 @@
/** Read public representation data stored in a buffer into a residue structure.
*
* The `mbedtls_mpi_mod_residue` and `mbedtls_mpi_mod_modulus` structures must
- * be compatible. The data will be automatically converted into the appropriate
- * representation based on the value of `m->int_rep field`.
+ * be compatible (Data in public representation is assumed to be in the m->ext_rep
+ * and will be padded to m->limbs). The data will be automatically converted
+ * into the appropriate internal representation based on the value of `m->int_rep`.
*
* \param r The address of the residue related to \p m. It must have as
* many limbs as the modulus \p m.
@@ -193,15 +194,17 @@
* of \p m is invalid or \p X is not less than \p m.
*/
int mbedtls_mpi_mod_read( mbedtls_mpi_mod_residue *r,
- mbedtls_mpi_mod_modulus *m,
- unsigned char *buf,
+ const mbedtls_mpi_mod_modulus *m,
+ const unsigned char *buf,
size_t buflen );
/** Write residue data onto a buffer using public representation data.
*
* The `mbedtls_mpi_mod_residue` and `mbedtls_mpi_mod_modulus` structures must
- * be compatible. The data will be automatically converted into the appropriate
- * representation based on the value of `m->int_rep field`.
+ * be compatible (Data will be exported onto the bufer using the m->ext_rep
+ * and will be read as of m->limbs length).The data will be automatically
+ * converted from the appropriate internal representation based on the
+ * value of `m->int_rep field`.
*
* \param r The address of the residue related to \p m. It must have as
* many limbs as the modulus \p m.
@@ -215,8 +218,8 @@
* \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if the external representation
* of \p m is invalid.
*/
-int mbedtls_mpi_mod_write( mbedtls_mpi_mod_residue *r,
- mbedtls_mpi_mod_modulus *m,
+int mbedtls_mpi_mod_write( const mbedtls_mpi_mod_residue *r,
+ const mbedtls_mpi_mod_modulus *m,
unsigned char *buf,
size_t buflen );
/* END MERGE SLOT 7 */