- BIGNUM **kinvp, BIGNUM **rp,
- const unsigned char *dgst, int dlen)
- {
- BN_CTX *ctx = NULL;
- BIGNUM *k,*kq,*K,*kinv=NULL,*r=NULL;
- int ret=0;
-
- if (!dsa->p || !dsa->q || !dsa->g)
- {
- DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS);
- return 0;
- }
-
- k = BN_new();
- kq = BN_new();
- if(!k || !kq) goto err;
-
- if (ctx_in == NULL)
- {
- if ((ctx=BN_CTX_new()) == NULL) goto err;
- }
- else
- ctx=ctx_in;
-
- if ((r=BN_new()) == NULL) goto err;
-
- /* Get random k */
- do
- {
-#ifndef OPENSSL_NO_SHA512
- if (dgst != NULL)
- {
- /* We calculate k from SHA512(private_key + H(message)
- * + random). This protects the private key from a weak
- * PRNG. */
- if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst,
- dlen, ctx))
- goto err;
- }
- else
-#endif
- 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_CONSTTIME);
- }
-
- if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
- {
- if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p,
- CRYPTO_LOCK_DSA,
- dsa->p, ctx))
- goto err;
- }
-
- /* Compute r = (g^k mod p) mod q */
-
- 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;
-
- /* Compute part of 's = inv(k) (m + xr) mod q' */
- if ((kinv=BN_mod_inverse(NULL,k,dsa->q,ctx)) == NULL) goto err;
-
- if (*kinvp != NULL) BN_clear_free(*kinvp);
- *kinvp=kinv;
- kinv=NULL;
- if (*rp != NULL) BN_clear_free(*rp);
- *rp=r;
- ret=1;
-err:
- if (!ret)
- {
- DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB);
- if (r != NULL)
- BN_clear_free(r);
- }
- if (ctx_in == NULL) BN_CTX_free(ctx);
- BN_clear_free(k);
- BN_clear_free(kq);
- return(ret);
- }
-
-static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
- DSA *dsa)
- {
- BN_CTX *ctx;
- BIGNUM *u1,*u2,*t1;
- BN_MONT_CTX *mont=NULL;
- int ret = -1, i;
- if (!dsa->p || !dsa->q || !dsa->g)
- {
- DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS);
- return -1;
- }
-
- i = BN_num_bits(dsa->q);
- /* fips 186-3 allows only different sizes for q */
- if (i != 160 && i != 224 && i != 256)
- {
- 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;
- }
- u1 = BN_new();
- u2 = BN_new();
- t1 = BN_new();
- ctx=BN_CTX_new();
- if(!u1 || !u2 || !t1 || !ctx) goto err;
-
- if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
- BN_ucmp(sig->r, dsa->q) >= 0)
- {
- ret = 0;
- goto err;
- }
- if (BN_is_zero(sig->s) || BN_is_negative(sig->s) ||
- BN_ucmp(sig->s, dsa->q) >= 0)
- {
- ret = 0;
- goto err;
- }
-
- /* Calculate W = inv(S) mod Q
- * save W in u2 */
- if ((BN_mod_inverse(u2,sig->s,dsa->q,ctx)) == NULL) goto err;
-
- /* save M in u1 */
- if (dgst_len > (i >> 3))
- /* if the digest length is greater than the size of q use the
- * BN_num_bits(dsa->q) leftmost bits of the digest, see
- * fips 186-3, 4.2 */
- dgst_len = (i >> 3);
- if (BN_bin2bn(dgst,dgst_len,u1) == NULL) goto err;
-
- /* u1 = M * w mod q */
- if (!BN_mod_mul(u1,u1,u2,dsa->q,ctx)) goto err;
-
- /* u2 = r * w mod q */
- if (!BN_mod_mul(u2,sig->r,u2,dsa->q,ctx)) goto err;
-
-
- if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
- {
- mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p,
- CRYPTO_LOCK_DSA, dsa->p, ctx);
- if (!mont)
- goto err;
- }
-
-
- DSA_MOD_EXP(goto err, dsa, t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx, mont);
- /* BN_copy(&u1,&t1); */
- /* let u1 = u1 mod q */
- if (!BN_mod(u1,t1,dsa->q,ctx)) goto err;
-
- /* V is now in u1. If the signature is correct, it will be
- * equal to R. */
- ret=(BN_ucmp(u1, sig->r) == 0);
-
- err:
- if (ret < 0) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB);
- if (ctx != NULL) BN_CTX_free(ctx);
- if(u1) BN_free(u1);
- if(u2) BN_free(u2);
- if(t1) BN_free(t1);
- return(ret);
- }
+ BIGNUM **kinvp, BIGNUM **rp,
+ const unsigned char *dgst, int dlen)
+{
+ BN_CTX *ctx = NULL;
+ BIGNUM *k, *kinv = NULL, *r = *rp;
+ int ret = 0;
+
+ if (!dsa->p || !dsa->q || !dsa->g) {
+ DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS);
+ return 0;
+ }
+
+ k = BN_new();
+ if (k == NULL)
+ goto err;
+
+ if (ctx_in == NULL) {
+ if ((ctx = BN_CTX_new()) == NULL)
+ goto err;
+ } else
+ ctx = ctx_in;
+
+ /* Get random k */
+ do {
+ if (dgst != NULL) {
+ /*
+ * We calculate k from SHA512(private_key + H(message) + random).
+ * This protects the private key from a weak PRNG.
+ */
+ if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst,
+ dlen, ctx))
+ goto err;
+ } else if (!BN_rand_range(k, dsa->q))
+ goto err;
+ } while (BN_is_zero(k));
+
+ BN_set_flags(k, BN_FLG_CONSTTIME);
+
+ if (dsa->flags & DSA_FLAG_CACHE_MONT_P) {
+ if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p,
+ dsa->lock, dsa->p, ctx))
+ goto err;
+ }
+
+ /* Compute r = (g^k mod p) mod q */
+
+ /*
+ * 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(k, k, dsa->q))
+ goto err;
+ if (BN_num_bits(k) <= BN_num_bits(dsa->q)) {
+ if (!BN_add(k, k, dsa->q))
+ goto err;
+ }
+
+ if ((dsa)->meth->bn_mod_exp != NULL) {
+ if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, k, dsa->p, ctx,
+ dsa->method_mont_p))
+ goto err;
+ } else {
+ if (!BN_mod_exp_mont(r, dsa->g, k, dsa->p, ctx, dsa->method_mont_p))
+ goto err;
+ }
+
+ if (!BN_mod(r, r, dsa->q, ctx))
+ goto err;
+
+ /* Compute part of 's = inv(k) (m + xr) mod q' */
+ if ((kinv = BN_mod_inverse(NULL, k, dsa->q, ctx)) == NULL)
+ goto err;
+
+ BN_clear_free(*kinvp);
+ *kinvp = kinv;
+ kinv = NULL;
+ ret = 1;
+ err:
+ if (!ret)
+ DSAerr(DSA_F_DSA_SIGN_SETUP, ERR_R_BN_LIB);
+ if (ctx != ctx_in)
+ BN_CTX_free(ctx);
+ BN_clear_free(k);
+ return ret;
+}
+
+static int dsa_do_verify(const unsigned char *dgst, int dgst_len,
+ DSA_SIG *sig, DSA *dsa)
+{
+ BN_CTX *ctx;
+ BIGNUM *u1, *u2, *t1;
+ BN_MONT_CTX *mont = NULL;
+ BIGNUM *r, *s;
+ int ret = -1, i;
+ if (!dsa->p || !dsa->q || !dsa->g) {
+ DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_MISSING_PARAMETERS);
+ return -1;
+ }
+
+ i = BN_num_bits(dsa->q);
+ /* fips 186-3 allows only different sizes for q */
+ if (i != 160 && i != 224 && i != 256) {
+ 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;
+ }
+ u1 = BN_new();
+ u2 = BN_new();
+ t1 = BN_new();
+ ctx = BN_CTX_new();
+ if (u1 == NULL || u2 == NULL || t1 == NULL || ctx == NULL)
+ goto err;
+
+ DSA_SIG_get0(&r, &s, sig);
+
+ if (BN_is_zero(r) || BN_is_negative(r) ||
+ BN_ucmp(r, dsa->q) >= 0) {
+ ret = 0;
+ goto err;
+ }
+ if (BN_is_zero(s) || BN_is_negative(s) ||
+ BN_ucmp(s, dsa->q) >= 0) {
+ ret = 0;
+ goto err;
+ }
+
+ /*
+ * Calculate W = inv(S) mod Q save W in u2
+ */
+ if ((BN_mod_inverse(u2, s, dsa->q, ctx)) == NULL)
+ goto err;
+
+ /* save M in u1 */
+ if (dgst_len > (i >> 3))
+ /*
+ * if the digest length is greater than the size of q use the
+ * BN_num_bits(dsa->q) leftmost bits of the digest, see fips 186-3,
+ * 4.2
+ */
+ dgst_len = (i >> 3);
+ if (BN_bin2bn(dgst, dgst_len, u1) == NULL)
+ goto err;
+
+ /* u1 = M * w mod q */
+ if (!BN_mod_mul(u1, u1, u2, dsa->q, ctx))
+ goto err;
+
+ /* u2 = r * w mod q */
+ if (!BN_mod_mul(u2, r, u2, dsa->q, ctx))
+ goto err;
+
+ if (dsa->flags & DSA_FLAG_CACHE_MONT_P) {
+ mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p,
+ dsa->lock, dsa->p, ctx);
+ if (!mont)
+ goto err;
+ }
+
+ if (dsa->meth->dsa_mod_exp != NULL) {
+ if (!dsa->meth->dsa_mod_exp(dsa, t1, dsa->g, u1, dsa->pub_key, u2,
+ dsa->p, ctx, mont))
+ goto err;
+ } else {
+ if (!BN_mod_exp2_mont(t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx,
+ mont))
+ goto err;
+ }
+
+ /* let u1 = u1 mod q */
+ if (!BN_mod(u1, t1, dsa->q, ctx))
+ goto err;
+
+ /*
+ * V is now in u1. If the signature is correct, it will be equal to R.
+ */
+ ret = (BN_ucmp(u1, r) == 0);
+
+ err:
+ if (ret < 0)
+ DSAerr(DSA_F_DSA_DO_VERIFY, ERR_R_BN_LIB);
+ BN_CTX_free(ctx);
+ BN_free(u1);
+ BN_free(u2);
+ BN_free(t1);
+ return (ret);
+}