static int
input_kex_dh_gex_reply(int type, u_int32_t seq, struct ssh *ssh)
{
Kex *kex = ssh->kex;
BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
struct sshkey *server_host_key;
u_char *kbuf = NULL, *hash, *signature = NULL, *server_host_key_blob = NULL;
size_t klen = 0, slen, sbloblen, hashlen;
int kout, r;
debug("got SSH2_MSG_KEX_DH_GEX_REPLY");
if (kex->verify_host_key == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
/* key, cert */
if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
&sbloblen)) != 0 ||
(r = sshkey_from_blob(server_host_key_blob, sbloblen,
&server_host_key)) != 0)
goto out;
if (server_host_key->type != kex->hostkey_type) {
r = SSH_ERR_KEY_TYPE_MISMATCH;
goto out;
}
if (kex->verify_host_key(server_host_key, ssh) == -1) {
r = SSH_ERR_SIGNATURE_INVALID;
goto out;
}
/* DH parameter f, server public DH key */
if ((dh_server_pub = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* signed H */
if ((r = sshpkt_get_bignum2(ssh, dh_server_pub)) != 0 ||
(r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
#ifdef DEBUG_KEXDH
fprintf(stderr, "dh_server_pub= ");
BN_print_fp(stderr, dh_server_pub);
fprintf(stderr, "\n");
debug("bits %d", BN_num_bits(dh_server_pub));
#endif
if (!dh_pub_is_valid(kex->dh, dh_server_pub)) {
sshpkt_disconnect(ssh, "bad server public DH value");
r = SSH_ERR_MESSAGE_INCOMPLETE;
goto out;
}
klen = DH_size(kex->dh);
if ((kbuf = malloc(klen)) == NULL ||
(shared_secret = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((kout = DH_compute_key(kbuf, dh_server_pub, kex->dh)) < 0 ||
BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
#ifdef DEBUG_KEXDH
dump_digest("shared secret", kbuf, kout);
#endif
if (ssh->compat & SSH_OLD_DHGEX)
kex->min = kex->max = -1;
/* calc and verify H */
if ((r = kexgex_hash(
kex->evp_md,
kex->client_version_string,
kex->server_version_string,
sshbuf_ptr(kex->my), sshbuf_len(kex->my),
sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
server_host_key_blob, sbloblen,
kex->min, kex->nbits, kex->max,
kex->dh->p, kex->dh->g,
kex->dh->pub_key,
dh_server_pub,
shared_secret,
&hash, &hashlen)) != 0)
goto out;
if ((r = sshkey_verify(server_host_key, signature, slen, hash,
hashlen, ssh->compat)) != 0)
goto out;
/* save session id */
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);
}
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
out:
DH_free(kex->dh);
kex->dh = NULL;
if (server_host_key_blob)
free(server_host_key_blob);
if (server_host_key)
sshkey_free(server_host_key);
if (dh_server_pub)
BN_clear_free(dh_server_pub);
if (kbuf) {
bzero(kbuf, klen);
free(kbuf);
}
if (shared_secret)
BN_clear_free(shared_secret);
if (signature)
free(signature);
return r;
}
static int
input_kex_c25519_init(int type, u_int32_t seq, struct ssh *ssh)
{
struct kex *kex = ssh->kex;
struct sshkey *server_host_private, *server_host_public;
struct sshbuf *shared_secret = NULL;
u_char *server_host_key_blob = NULL, *signature = NULL;
u_char server_key[CURVE25519_SIZE];
u_char *client_pubkey = NULL;
u_char server_pubkey[CURVE25519_SIZE];
u_char hash[SSH_DIGEST_MAX_LENGTH];
size_t slen, pklen, sbloblen, hashlen;
int r;
/* generate private key */
kexc25519_keygen(server_key, server_pubkey);
#ifdef DEBUG_KEXECDH
dump_digest("server private key:", server_key, sizeof(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 ((r = sshpkt_get_string(ssh, &client_pubkey, &pklen)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
if (pklen != CURVE25519_SIZE) {
r = SSH_ERR_SIGNATURE_INVALID;
goto out;
}
#ifdef DEBUG_KEXECDH
dump_digest("client public key:", client_pubkey, CURVE25519_SIZE);
#endif
if ((shared_secret = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = kexc25519_shared_key(server_key, client_pubkey,
shared_secret)) < 0)
goto out;
/* calc H */
if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
&sbloblen)) != 0)
goto out;
hashlen = sizeof(hash);
if ((r = kex_c25519_hash(
kex->hash_alg,
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_pubkey,
server_pubkey,
sshbuf_ptr(shared_secret), sshbuf_len(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;
/* 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_string(ssh, server_pubkey, sizeof(server_pubkey))) != 0 ||
(r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
goto out;
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
out:
explicit_bzero(hash, sizeof(hash));
explicit_bzero(server_key, sizeof(server_key));
free(server_host_key_blob);
free(signature);
free(client_pubkey);
sshbuf_free(shared_secret);
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
input_kex_ecdh_reply(int type, u_int32_t seq, void *ctxt)
{
struct ssh *ssh = ctxt;
struct kex *kex = ssh->kex;
const EC_GROUP *group;
EC_POINT *server_public = NULL;
EC_KEY *client_key;
BIGNUM *shared_secret = NULL;
struct sshkey *server_host_key = NULL;
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 (kex->verify_host_key == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
group = kex->ec_group;
client_key = kex->ec_client_key;
/* hostkey */
if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
&sbloblen)) != 0 ||
(r = sshkey_from_blob(server_host_key_blob, sbloblen,
&server_host_key)) != 0)
goto out;
if (server_host_key->type != kex->hostkey_type ||
(kex->hostkey_type == KEY_ECDSA &&
server_host_key->ecdsa_nid != kex->hostkey_nid)) {
r = SSH_ERR_KEY_TYPE_MISMATCH;
goto out;
}
if (kex->verify_host_key(server_host_key, ssh) == -1) {
r = SSH_ERR_SIGNATURE_INVALID;
goto out;
}
/* Q_S, server public key */
/* signed H */
if ((server_public = EC_POINT_new(group)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshpkt_get_ec(ssh, server_public, group)) != 0 ||
(r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
#ifdef DEBUG_KEXECDH
fputs("server public key:\n", stderr);
sshkey_dump_ec_point(group, server_public);
#endif
if (sshkey_ec_validate_public(group, server_public) != 0) {
sshpkt_disconnect(ssh, "invalid server public key");
r = SSH_ERR_MESSAGE_INCOMPLETE;
goto out;
}
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, server_public,
client_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 and verify H */
hashlen = sizeof(hash);
if ((r = kex_ecdh_hash(
kex->hash_alg,
group,
kex->client_version_string,
kex->server_version_string,
sshbuf_ptr(kex->my), sshbuf_len(kex->my),
sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
server_host_key_blob, sbloblen,
EC_KEY_get0_public_key(client_key),
server_public,
shared_secret,
hash, &hashlen)) != 0)
goto out;
if ((r = sshkey_verify(server_host_key, signature, slen, hash,
hashlen, ssh->compat)) != 0)
goto out;
/* save session id */
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);
}
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_public)
EC_POINT_clear_free(server_public);
if (kbuf) {
explicit_bzero(kbuf, klen);
free(kbuf);
}
if (shared_secret)
BN_clear_free(shared_secret);
sshkey_free(server_host_key);
free(server_host_key_blob);
free(signature);
return r;
}
int
input_kex_dh_init(int type, u_int32_t seq, void *ctxt)
{
struct ssh *ssh = ctxt;
struct kex *kex = ssh->kex;
BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
struct sshkey *server_host_public, *server_host_private;
u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
u_char hash[SSH_DIGEST_MAX_LENGTH];
size_t sbloblen, slen;
size_t klen = 0, hashlen;
int kout, r;
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;
}
/* key, cert */
if ((dh_client_pub = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
#ifdef DEBUG_KEXDH
fprintf(stderr, "dh_client_pub= ");
BN_print_fp(stderr, dh_client_pub);
fprintf(stderr, "\n");
debug("bits %d", BN_num_bits(dh_client_pub));
#endif
#ifdef DEBUG_KEXDH
DHparams_print_fp(stderr, kex->dh);
fprintf(stderr, "pub= ");
BN_print_fp(stderr, kex->dh->pub_key);
fprintf(stderr, "\n");
#endif
if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
sshpkt_disconnect(ssh, "bad client public DH value");
r = SSH_ERR_MESSAGE_INCOMPLETE;
goto out;
}
klen = DH_size(kex->dh);
if ((kbuf = malloc(klen)) == NULL ||
(shared_secret = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 ||
BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
#ifdef DEBUG_KEXDH
dump_digest("shared secret", kbuf, kout);
#endif
if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
&sbloblen)) != 0)
goto out;
/* calc H */
hashlen = sizeof(hash);
if ((r = kex_dh_hash(
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,
dh_client_pub,
kex->dh->pub_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(); */
/* send server hostkey, DH pubkey 'f' and singed H */
if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 ||
(r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
(r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || /* f */
(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));
DH_free(kex->dh);
kex->dh = NULL;
if (dh_client_pub)
BN_clear_free(dh_client_pub);
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
input_kex_c25519_reply(int type, u_int32_t seq, struct ssh *ssh)
{
struct kex *kex = ssh->kex;
struct sshkey *server_host_key = NULL;
struct sshbuf *shared_secret = NULL;
u_char *server_pubkey = NULL;
u_char *server_host_key_blob = NULL, *signature = NULL;
u_char *hash;
size_t slen, pklen, sbloblen, hashlen;
int r;
if (kex->verify_host_key == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
/* hostkey */
if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
&sbloblen)) != 0 ||
(r = sshkey_from_blob(server_host_key_blob, sbloblen,
&server_host_key)) != 0)
goto out;
if (server_host_key->type != kex->hostkey_type) {
r = SSH_ERR_KEY_TYPE_MISMATCH;
goto out;
}
if (kex->verify_host_key(server_host_key, ssh) == -1) {
r = SSH_ERR_SIGNATURE_INVALID;
goto out;
}
/* Q_S, server public key */
/* signed H */
if ((r = sshpkt_get_string(ssh, &server_pubkey, &pklen)) != 0 ||
(r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
if (pklen != CURVE25519_SIZE) {
r = SSH_ERR_SIGNATURE_INVALID;
goto out;
}
#ifdef DEBUG_KEXECDH
dump_digest("server public key:", server_pubkey, CURVE25519_SIZE);
#endif
if ((shared_secret = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = kexc25519_shared_key(kex->c25519_client_key, server_pubkey,
shared_secret)) < 0)
goto out;
/* calc and verify H */
if ((r = kex_c25519_hash(
kex->hash_alg,
kex->client_version_string,
kex->server_version_string,
sshbuf_ptr(kex->my), sshbuf_len(kex->my),
sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
server_host_key_blob, sbloblen,
kex->c25519_client_pubkey,
server_pubkey,
sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
&hash, &hashlen)) < 0)
goto out;
if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen,
ssh->compat)) != 0)
goto out;
/* save session id */
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);
}
if ((r = kex_derive_keys(ssh, hash, hashlen, sshbuf_ptr(shared_secret),
sshbuf_len(shared_secret))) == 0)
r = kex_send_newkeys(ssh);
r = 0;
out:
explicit_bzero(kex->c25519_client_key, sizeof(kex->c25519_client_key));
free(server_host_key_blob);
free(server_pubkey);
free(signature);
sshkey_free(server_host_key);
sshbuf_free(shared_secret);
return r;
}
/* Handle an incoming packet for the context CTX on the client side. */
static gsti_error_t
client_handle_packet (gsti_ctx_t ctx)
{
gsti_error_t err = 0;
_gsti_log_debug (ctx, "** FSM (client) state=%s\n",
state_to_string (ctx->state));
switch (ctx->state)
{
case FSM_kex_start:
err = _gsti_kex_proc_init_packet (ctx);
if (!err && ctx->gex.used)
{
err = _gsti_kex_send_gex_request (ctx);
if (!err)
ctx->state = FSM_kex_wait_gex;
}
else
{
if (!err)
err = kex_send_kexdh_reply (ctx);
if (!err)
ctx->state = FSM_kex_wait;
}
break;
case FSM_kex_wait_gex:
switch (ctx->pkt.type)
{
case SSH_MSG_KEX_DH_GEX_GROUP:
err = _gsti_kex_proc_gex_group (ctx);
if (!err)
err = _gsti_kex_send_kexdh_init (ctx);
if (!err)
ctx->state = FSM_kex_wait;
break;
default:
_gsti_log_err (ctx, "client got wrong packet "
"(pkttype=%d)\n",
ctx->pkt.type);
err = gsti_error (GPG_ERR_PROTOCOL_VIOLATION);
break;
}
break;
case FSM_kex_wait:
switch (ctx->pkt.type)
{
case SSH_MSG_KEXDH_INIT:
_gsti_log_err (ctx, "client got unexpected KEXDH_INIT\n");
err = gsti_error (GPG_ERR_PROTOCOL_VIOLATION);
break;
case SSH_MSG_KEXDH_REPLY:
err = kex_proc_kexdh_reply (ctx);
if (!err)
err = kex_send_newkeys (ctx);
if (!err)
ctx->state = FSM_kex_wait_newkeys;
break;
}
break;
case FSM_kex_wait_newkeys:
switch (ctx->pkt.type)
{
case SSH_MSG_NEWKEYS:
err = kex_proc_newkeys (ctx);
if (!err)
{
_gsti_log_info (ctx, "is local service? (%d)\n",
ctx->local_services ? 1 : 0);
err = kex_send_service_request (ctx, ctx->local_services ?
ctx->local_services->d
: "ssh-userauth");
_gsti_log_cont (ctx, "\n");
if (!err)
ctx->state = FSM_wait_service_accept;
}
break;
default:
log_error (ctx);
ctx->state = FSM_kex_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_wait_service_accept:
switch (ctx->pkt.type)
{
case SSH_MSG_SERVICE_ACCEPT:
err = kex_proc_service_accept (ctx);
if (!err)
{
_gsti_log_info (ctx, "service `");
_gsti_print_string (ctx, gsti_bstr_data (ctx->service_name),
gsti_bstr_length (ctx->service_name));
_gsti_log_cont (ctx, "' has been started (client)\n");
err = _gsti_auth_send_request_packet (ctx);
if (!err)
ctx->state = FSM_auth_wait_pkok;
}
break;
default:
log_error (ctx);
ctx->state = FSM_kex_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_auth_wait_pkok:
switch (ctx->pkt.type)
{
case SSH_MSG_USERAUTH_BANNER:
err = _gsti_auth_proc_banner_packet (ctx);
if (!err)
err = _gsti_banner_run_auth_cb (ctx);
break;
case SSH_MSG_USERAUTH_PK_OK:
err = _gsti_auth_proc_pkok_packet (ctx);
if (!err)
{
err = _gsti_auth_send_request_packet (ctx);
if (!err)
ctx->state = FSM_auth_wait_success;
}
break;
case SSH_MSG_USERAUTH_FAILURE:
_gsti_log_err (ctx, "user authentication failure\n");
ctx->state = FSM_auth_failed;
err = gsti_error (GPG_ERR_INV_NAME);
break;
default:
log_error (ctx);
ctx->state = FSM_auth_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_auth_wait_success:
switch (ctx->pkt.type)
{
case SSH_MSG_USERAUTH_SUCCESS:
err = _gsti_auth_proc_success_packet (ctx);
if (!err)
{
/* Signal to the user that the connection can be used now. */
if (ctx->control_cb)
(*ctx->control_cb) (ctx, ctx->control_cb_value,
GSTI_CONTROL_FLAG_KEX,
~GSTI_CONTROL_FLAG_KEX);
ctx->state = FSM_read;
}
break;
default:
log_error (ctx);
ctx->state = FSM_auth_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_read:
if (ctx->pkt.type >= SSH_MSG_CHANNEL_BEGIN
&& ctx->pkt.type <= SSH_MSG_CHANNEL_END)
err = _gsti_handle_channel_packet (ctx);
else if (ctx->pkt.type < SSH_MSG_USER_BEGIN)
err = gsti_error (GPG_ERR_INV_PACKET);
else
{
struct gsti_pktdesc_s pkt;
u32 seqno = ctx->recv_seqno - 1;
pkt.datalen = ctx->pkt.payload_len;
pkt.data = ctx->pkt.payload;
pkt.seqno = seqno;
if (ctx->user_pkt_handler_cb)
err = (*ctx->user_pkt_handler_cb) (ctx,
ctx->user_pkt_handler_cb_value,
&pkt);
}
break;
default:
log_state_error (ctx);
err = gsti_error (GPG_ERR_BUG);
}
return err;
}
/* Handle an incoming packet for the context CTX on the server side. */
static gsti_error_t
server_handle_packet (gsti_ctx_t ctx)
{
gsti_error_t err = 0;
_gsti_log_debug (ctx, "** FSM (server) state=%s\n",
state_to_string (ctx->state));
switch (ctx->state)
{
case FSM_kex_start:
switch (ctx->pkt.type)
{
case SSH_MSG_KEXINIT:
err = _gsti_kex_proc_init_packet (ctx);
if (!err)
ctx->state = FSM_kex_wait;
break;
default:
log_error (ctx);
ctx->state = FSM_kex_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_kex_wait:
switch (ctx->pkt.type)
{
case SSH_MSG_KEXDH_REPLY:
_gsti_log_err (ctx, "server got unexpected KEXDH_REPLY\n");
err = gsti_error (GPG_ERR_PROTOCOL_VIOLATION);
break;
case SSH_MSG_KEX_DH_GEX_REQUEST:
err = _gsti_kex_proc_gex_request (ctx);
if (!err)
err = _gsti_kex_send_gex_group (ctx);
if (!err)
{
_gsti_log_debug (ctx, "KEX: enable DH group exchange\n");
ctx->gex.used = 1;
}
break;
case SSH_MSG_KEXDH_INIT:
case SSH_MSG_KEX_DH_GEX_INIT:
err = kex_proc_kexdh_init (ctx);
if (!err)
err = kex_send_kexdh_reply (ctx);
if (!err)
err = kex_send_newkeys (ctx);
if (!err)
ctx->state = FSM_kex_wait_newkeys;
break;
default:
log_error (ctx);
ctx->state = FSM_kex_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_kex_wait_newkeys:
switch (ctx->pkt.type)
{
case SSH_MSG_NEWKEYS:
err = kex_proc_newkeys (ctx);
if (!err)
ctx->state = FSM_wait_service_request;
break;
default:
log_error (ctx);
ctx->state = FSM_kex_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_wait_service_request:
switch (ctx->pkt.type)
{
case SSH_MSG_SERVICE_REQUEST:
err = kex_proc_service_request (ctx);
if (!err)
err = kex_send_service_accept (ctx);
if (!err)
{
_gsti_log_info (ctx, "service `");
_gsti_print_string (ctx, gsti_bstr_data (ctx->service_name),
gsti_bstr_length (ctx->service_name));
_gsti_log_cont (ctx, "' has been started (server)\n");
ctx->state = FSM_auth_wait;
}
break;
default:
log_error (ctx);
ctx->state = FSM_kex_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_auth_wait:
switch (ctx->pkt.type)
{
case SSH_MSG_USERAUTH_REQUEST:
err = _gsti_auth_proc_request_packet (ctx);
if (!err)
err = _gsti_auth_run_auth_cb (ctx);
if (!err && ctx->banner)
err = _gsti_auth_send_banner_packet (ctx);
if (!err)
err = _gsti_auth_send_pkok_packet (ctx);
if (!err)
ctx->state = FSM_auth_wait_request;
else
err = _gsti_auth_send_failure_packet (ctx, ctx->auth);
break;
default:
log_error (ctx);
ctx->state = FSM_auth_failed;
err = gsti_error (GPG_ERR_INV_PACKET);
}
break;
case FSM_auth_wait_request:
switch (ctx->pkt.type)
{
case SSH_MSG_USERAUTH_REQUEST:
err = _gsti_auth_proc_request_packet (ctx);
if (!err)
err = _gsti_auth_send_success_packet (ctx);
if (!err)
{
/* Signal to the user that the connection can be used now. */
if (ctx->control_cb)
(*ctx->control_cb) (ctx, ctx->control_cb_value,
GSTI_CONTROL_FLAG_KEX,
~GSTI_CONTROL_FLAG_KEX);
ctx->state = FSM_read;
}
break;
}
break;
case FSM_read:
if (ctx->pkt.type >= SSH_MSG_CHANNEL_BEGIN
&& ctx->pkt.type <= SSH_MSG_CHANNEL_END)
err = _gsti_handle_channel_packet (ctx);
else if (ctx->pkt.type < SSH_MSG_USER_BEGIN)
err = gsti_error (GPG_ERR_INV_PACKET);
else
{
struct gsti_pktdesc_s pkt;
u32 seqno = ctx->recv_seqno - 1;
pkt.datalen = ctx->pkt.payload_len;
pkt.data = ctx->pkt.payload;
pkt.seqno = seqno;
if (ctx->user_pkt_handler_cb)
err = (*ctx->user_pkt_handler_cb) (ctx,
ctx->user_pkt_handler_cb_value,
&pkt);
}
break;
default:
log_state_error (ctx);
err = gsti_error (GPG_ERR_BUG);
}
return err;
}
