diff options
Diffstat (limited to 'mpi/mpi-mul.c')
| -rw-r--r-- | mpi/mpi-mul.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/mpi/mpi-mul.c b/mpi/mpi-mul.c index df8eb2586..e19ef5c6d 100644 --- a/mpi/mpi-mul.c +++ b/mpi/mpi-mul.c @@ -120,6 +120,7 @@ mpi_mul( MPI w, MPI u, MPI v) int assign_wp=0; mpi_ptr_t tmp_limb=NULL; + if( u->nlimbs < v->nlimbs ) { /* Swap U and V. */ usize = v->nlimbs; usign = v->sign; @@ -145,7 +146,15 @@ mpi_mul( MPI w, MPI u, MPI v) /* Ensure W has space enough to store the result. */ wsize = usize + vsize; - if( w->alloced < wsize ) { + if ( !mpi_is_secure (w) && (mpi_is_secure (u) || mpi_is_secure (v)) ) { + /* w is not allocated in secure space but u or v is. To make sure + * that no temporray results are stored in w, we temporary use + * a newly allocated limb space for w */ + wp = mpi_alloc_limb_space( wsize, 1 ); + assign_wp = 2; /* mark it as 2 so that we can later copy it back to + * mormal memory */ + } + else if( w->alloced < wsize ) { if( wp == up || wp == vp ) { wp = mpi_alloc_limb_space( wsize, mpi_is_secure(w) ); assign_wp = 1; @@ -180,8 +189,16 @@ mpi_mul( MPI w, MPI u, MPI v) wsize -= cy? 0:1; } - if( assign_wp ) + if( assign_wp ) { + if (assign_wp == 2) { + /* copy the temp wp from secure memory back to normal memory */ + mpi_ptr_t tmp_wp = mpi_alloc_limb_space (wsize, 0); + MPN_COPY (tmp_wp, wp, wsize); + mpi_free_limb_space (wp); + wp = tmp_wp; + } mpi_assign_limb_space( w, wp, wsize ); + } w->nlimbs = wsize; w->sign = sign_product; if( tmp_limb ) |