yuzu-emu/mbedtls
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Bignum: remove unnecessary NULL pointer checks

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A null pointer dereference, or null pointer plus small offset, is a
clean runtime error in most environments. So it's not particularly
useful to protect against this.

While at it make a null pointer check that is actually necessary more
robust.

Signed-off-by: Janos Follath <janos.follath@arm.com>
This commit is contained in:
Janos Follath 2022-08-11 15:19:00 +01:00
parent 296ea66442
commit 56a10f97ba
3 changed files with 5 additions and 12 deletions
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2
library/bignum_core.c
View file

@ -227,7 +227,7 @@ int mbedtls_mpi_core_read_be( mbedtls_mpi_uint *X,
/* Avoid calling `memcpy` with NULL source or destination argument, /* Avoid calling `memcpy` with NULL source or destination argument,
* even if buflen is 0. */ * even if buflen is 0. */
if( buflen != 0 ) if( buf != NULL )
{ {
Xp = (unsigned char*) X; Xp = (unsigned char*) X;
memcpy( Xp + overhead, buf, buflen ); memcpy( Xp + overhead, buf, buflen );

6
library/bignum_mod.c
View file

@ -47,9 +47,6 @@ int mbedtls_mpi_mod_residue_setup( mbedtls_mpi_mod_residue *r,
mbedtls_mpi_uint *p, mbedtls_mpi_uint *p,
size_t pn ) size_t pn )
{ {
if( p == NULL || m == NULL || r == NULL )
return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
if( pn < m->n || !mbedtls_mpi_core_lt_ct( m->p, p, pn ) ) if( pn < m->n || !mbedtls_mpi_core_lt_ct( m->p, p, pn ) )
return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
@ -112,9 +109,6 @@ int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
{ {
int ret = 0; int ret = 0;
if ( p == NULL || m == NULL )
return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
m->p = p; m->p = p;
m->n = pn; m->n = pn;
m->plen = mbedtls_mpi_core_bitlen( p, pn ); m->plen = mbedtls_mpi_core_bitlen( p, pn );

9
library/bignum_mod.h
View file

@ -78,9 +78,8 @@ typedef struct {
* \param pn The number of limbs of \p p. * \param pn The number of limbs of \p p.
* *
* \return \c 0 if successful. * \return \c 0 if successful.
* \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if \p r, \p m or \p p is #NULL * \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if \p pn is less than the limbs
* pointer, \p pn is less than the limbs in \p m or if \p p is not * in \p m or if \p p is not less than \p m.
* less than \p m.
*/ */
int mbedtls_mpi_mod_residue_setup( mbedtls_mpi_mod_residue *r, int mbedtls_mpi_mod_residue_setup( mbedtls_mpi_mod_residue *r,
mbedtls_mpi_mod_modulus *m, mbedtls_mpi_mod_modulus *m,
@ -119,8 +118,8 @@ void mbedtls_mpi_mod_modulus_init( mbedtls_mpi_mod_modulus *m );
* associated with \p m (see #mbedtls_mpi_mod_rep_selector). * associated with \p m (see #mbedtls_mpi_mod_rep_selector).
* *
* \return \c 0 if successful. * \return \c 0 if successful.
* \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if \p m or \p p is * \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if \p ext_rep or \p int_rep is
* #NULL pointer or if \p ext_rep or \p int_rep is invalid. * invalid.
*/ */
int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m, int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
mbedtls_mpi_uint *p, mbedtls_mpi_uint *p,