make sure fast_mp_montgomery_reduce() doesn't BOF

This fixes #63
2017-08-29 16:41:08 +02:00 · 2017-08-29 16:41:08 +02:00 · a4d905a030
commit a4d905a030
parent e9ce32a16d
2 changed files with 5 additions and 0 deletions
--- a/bn_fast_mp_montgomery_reduce.c
+++ b/bn_fast_mp_montgomery_reduce.c
@ -28,6 +28,10 @@ int fast_mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho)
   int     ix, res, olduse;
   mp_word W[MP_WARRAY];

+   if (x->used > MP_WARRAY) {
+      return MP_VAL;
+   }
+
   /* get old used count */
   olduse = x->used;

--- a/bn_mp_montgomery_reduce.c
+++ b/bn_mp_montgomery_reduce.c
@ -29,6 +29,7 @@ int mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho)
    */
   digs = (n->used * 2) + 1;
   if ((digs < MP_WARRAY) &&
+       (x->used <= MP_WARRAY) &&
       (n->used <
        (1 << ((CHAR_BIT * sizeof(mp_word)) - (2 * DIGIT_BIT))))) {
      return fast_mp_montgomery_reduce(x, n, rho);