#endif /* OPENSSL_NO_ASM */
-/* BN_div computes dv := num / divisor, rounding towards zero, and sets up
- * rm such that dv*divisor + rm = num holds.
+/* BN_div[_no_branch] computes dv := num / divisor, rounding towards
+ * zero, and sets up rm such that dv*divisor + rm = num holds.
* Thus:
* dv->neg == num->neg ^ divisor->neg (unless the result is zero)
* rm->neg == num->neg (unless the remainder is zero)
* If 'dv' or 'rm' is NULL, the respective value is not returned.
*/
+static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
+ const BIGNUM *divisor, BN_CTX *ctx);
int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
BN_CTX *ctx)
{
BN_ULONG d0,d1;
int num_n,div_n;
- if (BN_get_flags(num, BN_FLG_CONSTTIME) != 0)
+ if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0))
{
return BN_div_no_branch(dv, rm, num, divisor, ctx);
}
t2 -= d1;
}
#else /* !BN_LLONG */
- BN_ULONG t2l,t2h,ql,qh;
+ BN_ULONG t2l,t2h;
q=bn_div_words(n0,n1,d0);
#ifdef BN_DEBUG_LEVITTE
t2l = d1 * q;
t2h = BN_UMULT_HIGH(d1,q);
#else
+ {
+ BN_ULONG ql, qh;
t2l=LBITS(d1); t2h=HBITS(d1);
ql =LBITS(q); qh =HBITS(q);
mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
+ }
#endif
for (;;)
/* BN_div_no_branch is a special version of BN_div. It does not contain
* branches that may leak sensitive information.
*/
-int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
+static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
const BIGNUM *divisor, BN_CTX *ctx)
{
int norm_shift,i,loop;
if (BN_is_zero(divisor))
{
- BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
+ BNerr(BN_F_BN_DIV_NO_BRANCH,BN_R_DIV_BY_ZERO);
return(0);
}
t2 -= d1;
}
#else /* !BN_LLONG */
- BN_ULONG t2l,t2h,ql,qh;
+ BN_ULONG t2l,t2h;
q=bn_div_words(n0,n1,d0);
#ifdef BN_DEBUG_LEVITTE
t2l = d1 * q;
t2h = BN_UMULT_HIGH(d1,q);
#else
+ {
+ BN_ULONG ql, qh;
t2l=LBITS(d1); t2h=HBITS(d1);
ql =LBITS(q); qh =HBITS(q);
mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
+ }
#endif
for (;;)
rm->neg = neg;
bn_check_top(rm);
}
+ bn_correct_top(res);
BN_CTX_end(ctx);
return(1);
err: