static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
{
BN_CTX *ctx;
- BIGNUM k,*kinv=NULL,*r=NULL;
+ BIGNUM k,kq,*K,*kinv=NULL,*r=NULL;
int ret=0;
if (!dsa->p || !dsa->q || !dsa->g)
}
BN_init(&k);
+ BN_init(&kq);
if (ctx_in == NULL)
{
ctx=ctx_in;
if ((r=BN_new()) == NULL) goto err;
- kinv=NULL;
/* Get random k */
do
if (!BN_rand_range(&k, dsa->q)) goto err;
while (BN_is_zero(&k));
+ if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
+ {
+ BN_set_flags(&k, BN_FLG_EXP_CONSTTIME);
+ }
if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
{
}
/* Compute r = (g^k mod p) mod q */
- DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx,
+
+ if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
+ {
+ if (!BN_copy(&kq, &k)) goto err;
+
+ /* We do not want timing information to leak the length of k,
+ * so we compute g^k using an equivalent exponent of fixed length.
+ *
+ * (This is a kludge that we need because the BN_mod_exp_mont()
+ * does not let us specify the desired timing behaviour.) */
+
+ if (!BN_add(&kq, &kq, dsa->q)) goto err;
+ if (BN_num_bits(&kq) <= BN_num_bits(dsa->q))
+ {
+ if (!BN_add(&kq, &kq, dsa->q)) goto err;
+ }
+
+ K = &kq;
+ }
+ else
+ {
+ K = &k;
+ }
+ DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx,
dsa->method_mont_p);
if (!BN_mod(r,r,dsa->q,ctx)) goto err;
if (!ret)
{
DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB);
- if (kinv != NULL) BN_clear_free(kinv);
- if (r != NULL) BN_clear_free(r);
+ if (r != NULL)
+ BN_clear_free(r);
}
if (ctx_in == NULL) BN_CTX_free(ctx);
- if (kinv != NULL) BN_clear_free(kinv);
BN_clear_free(&k);
+ BN_clear_free(&kq);
return(ret);
}
return -1;
}
+ if (BN_num_bits(dsa->q) != 160)
+ {
+ DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE);
+ return -1;
+ }
+
+ if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS)
+ {
+ DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE);
+ return -1;
+ }
+
BN_init(&u1);
BN_init(&u2);
BN_init(&t1);