Move DSS functionality to a new file

1 files changed, 65 insertions, 0 deletions

diff --git a/lib/crypto/c_src/dss.c b/lib/crypto/c_src/dss.c
new file mode 100644
index 0000000000..b05304edb9
--- /dev/null
+++ b/lib/crypto/c_src/dss.c
@@ -0,0 +1,65 @@
+#include "dss.h"
+#include "bn.h"
+
+int get_dss_private_key(ErlNifEnv* env, ERL_NIF_TERM key, DSA *dsa)
+{
+    /* key=[P,Q,G,KEY] */
+    ERL_NIF_TERM head, tail;
+    BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL;
+    BIGNUM *dummy_pub_key, *priv_key = NULL;
+
+    if (!enif_get_list_cell(env, key, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_p)
+	|| !enif_get_list_cell(env, tail, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_q)
+	|| !enif_get_list_cell(env, tail, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_g)
+	|| !enif_get_list_cell(env, tail, &head, &tail)
+	|| !get_bn_from_bin(env, head, &priv_key)
+	|| !enif_is_empty_list(env,tail)) {
+	if (dsa_p) BN_free(dsa_p);
+	if (dsa_q) BN_free(dsa_q);
+	if (dsa_g) BN_free(dsa_g);
+	if (priv_key) BN_free(priv_key);
+	return 0;
+    }
+
+    /* Note: DSA_set0_key() does not allow setting only the
+     * private key, although DSA_sign() does not use the
+     * public key. Work around this limitation by setting
+     * the public key to a copy of the private key.
+     */
+    dummy_pub_key = BN_dup(priv_key);
+
+    DSA_set0_pqg(dsa, dsa_p, dsa_q, dsa_g);
+    DSA_set0_key(dsa, dummy_pub_key, priv_key);
+    return 1;
+}
+
+
+int get_dss_public_key(ErlNifEnv* env, ERL_NIF_TERM key, DSA *dsa)
+{
+    /* key=[P, Q, G, Y] */
+    ERL_NIF_TERM head, tail;
+    BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL, *dsa_y = NULL;
+
+    if (!enif_get_list_cell(env, key, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_p)
+	|| !enif_get_list_cell(env, tail, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_q)
+	|| !enif_get_list_cell(env, tail, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_g)
+	|| !enif_get_list_cell(env, tail, &head, &tail)
+	|| !get_bn_from_bin(env, head, &dsa_y)
+	|| !enif_is_empty_list(env,tail)) {
+	if (dsa_p) BN_free(dsa_p);
+	if (dsa_q) BN_free(dsa_q);
+	if (dsa_g) BN_free(dsa_g);
+	if (dsa_y) BN_free(dsa_y);
+	return 0;
+    }
+
+    DSA_set0_pqg(dsa, dsa_p, dsa_q, dsa_g);
+    DSA_set0_key(dsa, dsa_y, NULL);
+    return 1;
+}