Bignum: clean up use of enums
- Made use of enums in struct and function declaration
- All enums are handled by switch case now
- If the switch does nothing on default, omit the default case to make
compiler warnings more powerful
- The two enums are now disjoint and the value 1 is skipped to make
mistakes easier to detect
Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/library/bignum_mod.c b/library/bignum_mod.c
index 63f9172..c424854 100644
--- a/library/bignum_mod.c
+++ b/library/bignum_mod.c
@@ -88,10 +88,12 @@
switch( m->int_rep )
{
case MBEDTLS_MPI_MOD_REP_MONTGOMERY:
- mbedtls_free( m->rep.mont ); break;
+ mbedtls_free( m->rep.mont );
+ break;
case MBEDTLS_MPI_MOD_REP_OPT_RED:
- mbedtls_free( m->rep.ored ); break;
- default:
+ mbedtls_free( m->rep.ored );
+ break;
+ case MBEDTLS_MPI_MOD_REP_INVALID:
break;
}
@@ -105,8 +107,8 @@
int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
mbedtls_mpi_uint *p,
size_t pn,
- int ext_rep,
- int int_rep )
+ mbedtls_mpi_mod_ext_rep ext_rep,
+ mbedtls_mpi_mod_rep_selector int_rep )
{
int ret = 0;
@@ -121,7 +123,8 @@
{
case MBEDTLS_MPI_MOD_EXT_REP_LE:
case MBEDTLS_MPI_MOD_EXT_REP_BE:
- m->ext_rep = ext_rep; break;
+ m->ext_rep = ext_rep;
+ break;
default:
ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
goto exit;
@@ -131,10 +134,12 @@
{
case MBEDTLS_MPI_MOD_REP_MONTGOMERY:
m->int_rep = int_rep;
- m->rep.mont = NULL; break;
+ m->rep.mont = NULL;
+ break;
case MBEDTLS_MPI_MOD_REP_OPT_RED:
m->int_rep = int_rep;
- m->rep.ored = NULL; break;
+ m->rep.ored = NULL;
+ break;
default:
ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
goto exit;
diff --git a/library/bignum_mod.h b/library/bignum_mod.h
index 254a744..7950f09 100644
--- a/library/bignum_mod.h
+++ b/library/bignum_mod.h
@@ -26,6 +26,22 @@
#include "mbedtls/bignum.h"
#endif
+/* Skip 1 as it is slightly easier to accidentally pass to functions. */
+typedef enum
+{
+ MBEDTLS_MPI_MOD_REP_INVALID = 0,
+ MBEDTLS_MPI_MOD_REP_MONTGOMERY = 2,
+ MBEDTLS_MPI_MOD_REP_OPT_RED
+} mbedtls_mpi_mod_rep_selector;
+
+/* Make mbedtls_mpi_mod_rep_selector and mbedtls_mpi_mod_ext_rep disjoint to
+ * make it easier to catch when they are accidentally swapped. */
+typedef enum
+{
+ MBEDTLS_MPI_MOD_EXT_REP_INVALID = 0,
+ MBEDTLS_MPI_MOD_EXT_REP_LE = 8,
+ MBEDTLS_MPI_MOD_EXT_REP_BE
+} mbedtls_mpi_mod_ext_rep;
typedef struct
{
@@ -38,10 +54,10 @@
typedef struct {
mbedtls_mpi_uint *p;
- size_t n; // number of limbs
- size_t plen; // bitlen of p
- int ext_rep; // signals external representation (eg. byte order)
- int int_rep; // selector to signal the active member of the union
+ size_t n; // number of limbs
+ size_t plen; // bitlen of p
+ mbedtls_mpi_mod_ext_rep ext_rep; // signals external representation (eg. byte order)
+ mbedtls_mpi_mod_rep_selector int_rep; // selector to signal the active member of the union
union rep
{
mbedtls_mpi_mont_struct mont;
@@ -49,21 +65,6 @@
} rep;
} mbedtls_mpi_mod_modulus;
-typedef enum
-{
- MBEDTLS_MPI_MOD_REP_INVALID = 0,
- MBEDTLS_MPI_MOD_REP_MONTGOMERY,
- MBEDTLS_MPI_MOD_REP_OPT_RED
-} mbedtls_mpi_mod_rep_selector;
-
-typedef enum
-{
- MBEDTLS_MPI_MOD_EXT_REP_INVALID = 0,
- MBEDTLS_MPI_MOD_EXT_REP_LE,
- MBEDTLS_MPI_MOD_EXT_REP_BE
-} mbedtls_mpi_mod_ext_rep;
-
-
/** Setup a residue structure.
*
* \param r The address of residue to setup. The size is determined by \p m.
@@ -124,8 +125,8 @@
int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
mbedtls_mpi_uint *p,
size_t pn,
- int ext_rep,
- int int_rep );
+ mbedtls_mpi_mod_ext_rep ext_rep,
+ mbedtls_mpi_mod_rep_selector int_rep );
/** Free elements of a modulus structure.
*
diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c
index 305cec1..d3cd770 100644
--- a/library/bignum_mod_raw.c
+++ b/library/bignum_mod_raw.c
@@ -48,13 +48,17 @@
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
- if( m->ext_rep == MBEDTLS_MPI_MOD_EXT_REP_LE )
- ret = mbedtls_mpi_core_read_le( X, m->n, buf, buflen );
-
- else if( m->ext_rep == MBEDTLS_MPI_MOD_EXT_REP_BE )
- ret = mbedtls_mpi_core_read_be( X, m->n, buf, buflen );
- else
- return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+ switch( m->ext_rep )
+ {
+ case MBEDTLS_MPI_MOD_EXT_REP_LE:
+ ret = mbedtls_mpi_core_read_le( X, m->n, buf, buflen );
+ break;
+ case MBEDTLS_MPI_MOD_EXT_REP_BE:
+ ret = mbedtls_mpi_core_read_be( X, m->n, buf, buflen );
+ break;
+ default:
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+ }
if( ret != 0 )
goto cleanup;
@@ -75,16 +79,15 @@
unsigned char *buf,
size_t buflen )
{
- if( m->ext_rep == MBEDTLS_MPI_MOD_EXT_REP_LE )
- return mbedtls_mpi_core_write_le( X, m->n, buf, buflen );
-
- else if( m->ext_rep == MBEDTLS_MPI_MOD_EXT_REP_BE )
- return mbedtls_mpi_core_write_be( X, m->n, buf, buflen );
-
- else
- return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
-
- return( 0 );
+ switch( m->ext_rep )
+ {
+ case MBEDTLS_MPI_MOD_EXT_REP_LE:
+ return mbedtls_mpi_core_write_le( X, m->n, buf, buflen );
+ case MBEDTLS_MPI_MOD_EXT_REP_BE:
+ return mbedtls_mpi_core_write_be( X, m->n, buf, buflen );
+ default:
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+ }
}
#endif /* MBEDTLS_BIGNUM_C */