static int ubsec_dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1,
BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, BIGNUM *m,
BN_CTX *ctx, BN_MONT_CTX *in_mont)
{
BIGNUM t;
int to_return = 0;
BN_init(&t);
/* let rr = a1 ^ p1 mod m */
if (!ubsec_mod_exp(rr,a1,p1,m,ctx)) goto end;
/* let t = a2 ^ p2 mod m */
if (!ubsec_mod_exp(&t,a2,p2,m,ctx)) goto end;
/* let rr = rr * t mod m */
if (!BN_mod_mul(rr,rr,&t,m,ctx)) goto end;
to_return = 1;
end:
BN_free(&t);
return to_return;
}
/*
* This function is aliased to mod_exp (with the mont stuff dropped).
*/
static int ubsec_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx,
BN_MONT_CTX *m_ctx)
{
int ret = 0;
/* Do in software if the key is too large for the hardware. */
if (BN_num_bits(m) > max_key_len) {
const RSA_METHOD *meth = RSA_PKCS1_OpenSSL();
ret = (*meth->bn_mod_exp) (r, a, p, m, ctx, m_ctx);
} else {
ret = ubsec_mod_exp(r, a, p, m, ctx);
}
return ret;
}
/* This function is aliased to mod_exp (with the dh and mont dropped). */
static int ubsec_mod_exp_dh(const DH *dh, BIGNUM *r, const BIGNUM *a,
const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
BN_MONT_CTX *m_ctx)
{
return ubsec_mod_exp(r, a, p, m, ctx);
}
static int ubsec_mod_exp_dsa(DSA *dsa, BIGNUM *r, BIGNUM *a,
const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
BN_MONT_CTX *m_ctx)
{
return ubsec_mod_exp(r, a, p, m, ctx);
}