int
kexecdh_client(ncrack_ssh_state *nstate)
{
struct kex *kex = nstate->kex;
EC_KEY *client_key = NULL;
const EC_GROUP *group;
const EC_POINT *public_key;
int r;
//printf("kexecdh client \n");
if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (EC_KEY_generate_key(client_key) != 1) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
group = EC_KEY_get0_group(client_key);
public_key = EC_KEY_get0_public_key(client_key);
if ((r = sshpkt_start(nstate, SSH2_MSG_KEX_ECDH_INIT)) != 0 ||
(r = sshpkt_put_ec(nstate, public_key, group)) != 0 ||
(r = sshpkt_send(nstate)) != 0)
goto out;
debug("sending SSH2_MSG_KEX_ECDH_INIT");
#ifdef DEBUG_KEXECDH
fputs("client private key:\n", stderr);
sshkey_dump_ec_key(client_key);
#endif
kex->ec_client_key = client_key;
kex->ec_group = group;
client_key = NULL; /* owned by the kex */
debug("expecting SSH2_MSG_KEX_ECDH_REPLY");
//ssh_dispatch_set(ssh, SSH2_MSG_KEX_ECDH_REPLY, &input_kex_ecdh_reply);
r = 0;
out:
if (client_key)
EC_KEY_free(client_key);
return r;
}
static int
input_kex_ecdh_init(int type, u_int32_t seq, struct ssh *ssh)
{
struct kex *kex = ssh->kex;
EC_POINT *client_public;
EC_KEY *server_key = NULL;
const EC_GROUP *group;
const EC_POINT *public_key;
BIGNUM *shared_secret = NULL;
struct sshkey *server_host_private, *server_host_public;
u_char *server_host_key_blob = NULL, *signature = NULL;
u_char *kbuf = NULL;
u_char hash[SSH_DIGEST_MAX_LENGTH];
size_t slen, sbloblen;
size_t klen = 0, hashlen;
int r;
if ((server_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (EC_KEY_generate_key(server_key) != 1) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
group = EC_KEY_get0_group(server_key);
#ifdef DEBUG_KEXECDH
fputs("server private key:\n", stderr);
sshkey_dump_ec_key(server_key);
#endif
if (kex->load_host_public_key == NULL ||
kex->load_host_private_key == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
server_host_public = kex->load_host_public_key(kex->hostkey_type,
kex->hostkey_nid, ssh);
server_host_private = kex->load_host_private_key(kex->hostkey_type,
kex->hostkey_nid, ssh);
if (server_host_public == NULL) {
r = SSH_ERR_NO_HOSTKEY_LOADED;
goto out;
}
if ((client_public = EC_POINT_new(group)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshpkt_get_ec(ssh, client_public, group)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
#ifdef DEBUG_KEXECDH
fputs("client public key:\n", stderr);
sshkey_dump_ec_point(group, client_public);
#endif
if (sshkey_ec_validate_public(group, client_public) != 0) {
sshpkt_disconnect(ssh, "invalid client public key");
r = SSH_ERR_MESSAGE_INCOMPLETE;
goto out;
}
/* Calculate shared_secret */
klen = (EC_GROUP_get_degree(group) + 7) / 8;
if ((kbuf = malloc(klen)) == NULL ||
(shared_secret = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (ECDH_compute_key(kbuf, klen, client_public,
server_key, NULL) != (int)klen ||
BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
#ifdef DEBUG_KEXECDH
dump_digest("shared secret", kbuf, klen);
#endif
/* calc H */
if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
&sbloblen)) != 0)
goto out;
hashlen = sizeof(hash);
if ((r = kex_ecdh_hash(
kex->hash_alg,
group,
kex->client_version_string,
kex->server_version_string,
sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
sshbuf_ptr(kex->my), sshbuf_len(kex->my),
server_host_key_blob, sbloblen,
client_public,
EC_KEY_get0_public_key(server_key),
shared_secret,
hash, &hashlen)) != 0)
goto out;
/* save session id := H */
if (kex->session_id == NULL) {
kex->session_id_len = hashlen;
kex->session_id = malloc(kex->session_id_len);
if (kex->session_id == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(kex->session_id, hash, kex->session_id_len);
}
/* sign H */
if ((r = kex->sign(server_host_private, server_host_public, &signature,
&slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
goto out;
/* destroy_sensitive_data(); */
public_key = EC_KEY_get0_public_key(server_key);
/* send server hostkey, ECDH pubkey 'Q_S' and signed H */
if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_REPLY)) != 0 ||
(r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
(r = sshpkt_put_ec(ssh, public_key, group)) != 0 ||
(r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
goto out;
if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
out:
explicit_bzero(hash, sizeof(hash));
if (kex->ec_client_key) {
EC_KEY_free(kex->ec_client_key);
kex->ec_client_key = NULL;
}
if (server_key)
EC_KEY_free(server_key);
if (kbuf) {
explicit_bzero(kbuf, klen);
free(kbuf);
}
if (shared_secret)
BN_clear_free(shared_secret);
free(server_host_key_blob);
free(signature);
return r;
}
static int
sshkey_parse_private_pem(struct sshbuf *blob, int type, const char *passphrase,
struct sshkey **keyp, char **commentp)
{
EVP_PKEY *pk = NULL;
struct sshkey *prv = NULL;
char *name = "<no key>";
BIO *bio = NULL;
int r;
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX)
return SSH_ERR_ALLOC_FAIL;
if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) !=
(int)sshbuf_len(blob)) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((pk = PEM_read_bio_PrivateKey(bio, NULL, NULL,
(char *)passphrase)) == NULL) {
r = SSH_ERR_KEY_WRONG_PASSPHRASE;
goto out;
}
if (pk->type == EVP_PKEY_RSA &&
(type == KEY_UNSPEC || type == KEY_RSA)) {
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->rsa = EVP_PKEY_get1_RSA(pk);
prv->type = KEY_RSA;
name = "rsa w/o comment";
#ifdef DEBUG_PK
RSA_print_fp(stderr, prv->rsa, 8);
#endif
if (RSA_blinding_on(prv->rsa, NULL) != 1) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
} else if (pk->type == EVP_PKEY_DSA &&
(type == KEY_UNSPEC || type == KEY_DSA)) {
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->dsa = EVP_PKEY_get1_DSA(pk);
prv->type = KEY_DSA;
name = "dsa w/o comment";
#ifdef DEBUG_PK
DSA_print_fp(stderr, prv->dsa, 8);
#endif
} else if (pk->type == EVP_PKEY_EC &&
(type == KEY_UNSPEC || type == KEY_ECDSA)) {
if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
prv->type = KEY_ECDSA;
prv->ecdsa_nid = sshkey_ecdsa_key_to_nid(prv->ecdsa);
if (prv->ecdsa_nid == -1 ||
sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
sshkey_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
sshkey_ec_validate_private(prv->ecdsa) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
name = "ecdsa w/o comment";
#ifdef DEBUG_PK
if (prv != NULL && prv->ecdsa != NULL)
sshkey_dump_ec_key(prv->ecdsa);
#endif
} else {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if (commentp != NULL &&
(*commentp = strdup(name)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
r = 0;
*keyp = prv;
prv = NULL;
out:
BIO_free(bio);
if (pk != NULL)
EVP_PKEY_free(pk);
if (prv != NULL)
sshkey_free(prv);
return r;
}
