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authorDoug Hogan <[email protected]>2019-01-07 18:47:16 -0800
committerDoug Hogan <[email protected]>2019-01-08 01:11:58 -0800
commitcfd08eb130fe9cdadd3d291526f761359b84bd1e (patch)
tree8a0015a2e9420de5efed91561f5242edfc9914aa /lib/crypto/c_src
parent1c540d41740945322f3aaf7b0ee66dda09d258f2 (diff)
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Revamp dh_compute_key_nif()
Diffstat (limited to 'lib/crypto/c_src')
-rw-r--r--lib/crypto/c_src/dh.c134
1 files changed, 89 insertions, 45 deletions
diff --git a/lib/crypto/c_src/dh.c b/lib/crypto/c_src/dh.c
index 10fd122658..e3b5b11e9c 100644
--- a/lib/crypto/c_src/dh.c
+++ b/lib/crypto/c_src/dh.c
@@ -186,61 +186,105 @@ ERL_NIF_TERM dh_generate_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM ar
ERL_NIF_TERM dh_compute_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (OthersPublicKey, MyPrivateKey, DHParams=[P,G]) */
- BIGNUM *other_pub_key = NULL,
- *dh_p = NULL,
- *dh_g = NULL;
- DH *dh_priv = DH_new();
+ BIGNUM *other_pub_key = NULL;
+ BIGNUM *dh_p = NULL;
+ BIGNUM *dh_g = NULL;
+ BIGNUM *dummy_pub_key = NULL;
+ BIGNUM *priv_key = NULL;
+ DH *dh_priv = NULL;
+ ERL_NIF_TERM head, tail, ret;
+ ErlNifBinary ret_bin;
+ int size;
+ int ret_bin_alloc = 0;
+ int dh_size;
/* Check the arguments and get
my private key (dh_priv),
the peer's public key (other_pub_key),
the parameters p & q
*/
+ if (argc != 3)
+ goto bad_arg;
+
+ if (!get_bn_from_bin(env, argv[0], &other_pub_key))
+ goto bad_arg;
+ if (!get_bn_from_bin(env, argv[1], &priv_key))
+ goto bad_arg;
+
+ if (!enif_get_list_cell(env, argv[2], &head, &tail))
+ goto bad_arg;
+ if (!get_bn_from_bin(env, head, &dh_p))
+ goto bad_arg;
+
+ if (!enif_get_list_cell(env, tail, &head, &tail))
+ goto bad_arg;
+ if (!get_bn_from_bin(env, head, &dh_g))
+ goto bad_arg;
+
+ if (!enif_is_empty_list(env, tail))
+ goto bad_arg;
- {
- BIGNUM *dummy_pub_key = NULL,
- *priv_key = NULL;
- ERL_NIF_TERM head, tail;
-
- if (!get_bn_from_bin(env, argv[0], &other_pub_key)
- || !get_bn_from_bin(env, argv[1], &priv_key)
- || !enif_get_list_cell(env, argv[2], &head, &tail)
- || !get_bn_from_bin(env, head, &dh_p)
- || !enif_get_list_cell(env, tail, &head, &tail)
- || !get_bn_from_bin(env, head, &dh_g)
- || !enif_is_empty_list(env, tail)
-
- /* Note: DH_set0_key() does not allow setting only the
- * private key, although DH_compute_key() 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))
- || !DH_set0_key(dh_priv, dummy_pub_key, priv_key)
- || !DH_set0_pqg(dh_priv, dh_p, NULL, dh_g)
- ) {
- if (dh_p) BN_free(dh_p);
- if (dh_g) BN_free(dh_g);
- if (other_pub_key) BN_free(other_pub_key);
- if (dummy_pub_key) BN_free(dummy_pub_key);
- if (priv_key) BN_free(priv_key);
- return enif_make_badarg(env);
- }
+ /* Note: DH_set0_key() does not allow setting only the
+ * private key, although DH_compute_key() does not use the
+ * public key. Work around this limitation by setting
+ * the public key to a copy of the private key.
+ */
+ if ((dummy_pub_key = BN_dup(priv_key)) == NULL)
+ goto err;
+ if ((dh_priv = DH_new()) == NULL)
+ goto err;
+
+ if (!DH_set0_key(dh_priv, dummy_pub_key, priv_key))
+ goto err;
+ /* dh_priv owns dummy_pub_key and priv_key now */
+ dummy_pub_key = NULL;
+ priv_key = NULL;
+
+ if (!DH_set0_pqg(dh_priv, dh_p, NULL, dh_g))
+ goto err;
+ /* dh_priv owns dh_p and dh_g now */
+ dh_p = NULL;
+ dh_g = NULL;
+
+ if ((dh_size = DH_size(dh_priv)) < 0)
+ goto err;
+ if (!enif_alloc_binary((size_t)dh_size, &ret_bin))
+ goto err;
+ ret_bin_alloc = 1;
+
+ if ((size = DH_compute_key(ret_bin.data, other_pub_key, dh_priv)) < 0)
+ goto err;
+ if (size == 0)
+ goto err;
+
+ if ((size_t)size != ret_bin.size) {
+ if (!enif_realloc_binary(&ret_bin, (size_t)size))
+ goto err;
}
- {
- ErlNifBinary ret_bin;
- int size;
- enif_alloc_binary(DH_size(dh_priv), &ret_bin);
- size = DH_compute_key(ret_bin.data, other_pub_key, dh_priv);
+ ret = enif_make_binary(env, &ret_bin);
+ ret_bin_alloc = 0;
+ goto done;
+
+ bad_arg:
+ err:
+ if (ret_bin_alloc)
+ enif_release_binary(&ret_bin);
+ ret = enif_make_badarg(env);
+
+ done:
+ if (other_pub_key)
BN_free(other_pub_key);
+ if (priv_key)
+ BN_free(priv_key);
+ if (dh_p)
+ BN_free(dh_p);
+ if (dh_g)
+ BN_free(dh_g);
+ if (dummy_pub_key)
+ BN_free(dummy_pub_key);
+ if (dh_priv)
DH_free(dh_priv);
- if (size<=0) {
- enif_release_binary(&ret_bin);
- return atom_error;
- }
- if (size != ret_bin.size) enif_realloc_binary(&ret_bin, size);
- return enif_make_binary(env, &ret_bin);
- }
+ return ret;
}