static int dh_handshake_server(ssh_session session) { ssh_key privkey; ssh_string sig_blob; ssh_string f; ssh_string pubkey_blob = NULL; int rc; if (ssh_dh_generate_y(session) < 0) { ssh_set_error(session, SSH_FATAL, "Could not create y number"); return -1; } if (ssh_dh_generate_f(session) < 0) { ssh_set_error(session, SSH_FATAL, "Could not create f number"); return -1; } f = ssh_dh_get_f(session); if (f == NULL) { ssh_set_error(session, SSH_FATAL, "Could not get the f number"); return -1; } if (ssh_get_key_params(session,&privkey) != SSH_OK){ ssh_string_free(f); return -1; } if (ssh_dh_build_k(session) < 0) { ssh_set_error(session, SSH_FATAL, "Could not import the public key"); ssh_string_free(f); return -1; } if (ssh_make_sessionid(session) != SSH_OK) { ssh_set_error(session, SSH_FATAL, "Could not create a session id"); ssh_string_free(f); return -1; } sig_blob = ssh_srv_pki_do_sign_sessionid(session, privkey); if (sig_blob == NULL) { ssh_set_error(session, SSH_FATAL, "Could not sign the session id"); ssh_string_free(f); return -1; } rc = ssh_dh_get_next_server_publickey_blob(session, &pubkey_blob); if (rc != SSH_OK) { ssh_set_error_oom(session); ssh_string_free(f); ssh_string_free(sig_blob); return -1; } rc = ssh_buffer_pack(session->out_buffer, "bSSS", SSH2_MSG_KEXDH_REPLY, pubkey_blob, f, sig_blob); ssh_string_free(f); ssh_string_free(sig_blob); ssh_string_free(pubkey_blob); if(rc != SSH_OK){ ssh_set_error_oom(session); ssh_buffer_reinit(session->out_buffer); return -1; } if (ssh_packet_send(session) == SSH_ERROR) { return -1; } if (ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) { ssh_buffer_reinit(session->out_buffer); return -1; } if (ssh_packet_send(session) == SSH_ERROR) { return -1; } SSH_LOG(SSH_LOG_PACKET, "SSH_MSG_NEWKEYS sent"); session->dh_handshake_state=DH_STATE_NEWKEYS_SENT; return 0; }
int ssh_make_sessionid(ssh_session session) { ssh_string num = NULL; ssh_buffer server_hash = NULL; ssh_buffer client_hash = NULL; ssh_buffer buf = NULL; ssh_string server_pubkey_blob = NULL; const_bignum client_pubkey, server_pubkey; #ifdef WITH_GEX const_bignum modulus, generator; #endif int rc = SSH_ERROR; buf = ssh_buffer_new(); if (buf == NULL) { return rc; } rc = ssh_buffer_pack(buf, "ss", session->clientbanner, session->serverbanner); if (rc == SSH_ERROR) { goto error; } if (session->client) { server_hash = session->in_hashbuf; client_hash = session->out_hashbuf; } else { server_hash = session->out_hashbuf; client_hash = session->in_hashbuf; } /* * Handle the two final fields for the KEXINIT message (RFC 4253 7.1): * * boolean first_kex_packet_follows * uint32 0 (reserved for future extension) */ rc = ssh_buffer_add_u8(server_hash, 0); if (rc < 0) { goto error; } rc = ssh_buffer_add_u32(server_hash, 0); if (rc < 0) { goto error; } /* These fields are handled for the server case in ssh_packet_kexinit. */ if (session->client) { rc = ssh_buffer_add_u8(client_hash, 0); if (rc < 0) { goto error; } rc = ssh_buffer_add_u32(client_hash, 0); if (rc < 0) { goto error; } } rc = ssh_dh_get_next_server_publickey_blob(session, &server_pubkey_blob); if (rc != SSH_OK) { goto error; } rc = ssh_buffer_pack(buf, "dPdPS", ssh_buffer_get_len(client_hash), ssh_buffer_get_len(client_hash), ssh_buffer_get(client_hash), ssh_buffer_get_len(server_hash), ssh_buffer_get_len(server_hash), ssh_buffer_get(server_hash), server_pubkey_blob); ssh_string_free(server_pubkey_blob); if(rc != SSH_OK){ goto error; } switch(session->next_crypto->kex_type) { case SSH_KEX_DH_GROUP1_SHA1: case SSH_KEX_DH_GROUP14_SHA1: case SSH_KEX_DH_GROUP16_SHA512: case SSH_KEX_DH_GROUP18_SHA512: rc = ssh_dh_keypair_get_keys(session->next_crypto->dh_ctx, DH_CLIENT_KEYPAIR, NULL, &client_pubkey); if (rc != SSH_OK) { goto error; } rc = ssh_dh_keypair_get_keys(session->next_crypto->dh_ctx, DH_SERVER_KEYPAIR, NULL, &server_pubkey); if (rc != SSH_OK) { goto error; } rc = ssh_buffer_pack(buf, "BB", client_pubkey, server_pubkey); if (rc != SSH_OK) { goto error; } break; #ifdef WITH_GEX case SSH_KEX_DH_GEX_SHA1: case SSH_KEX_DH_GEX_SHA256: rc = ssh_dh_keypair_get_keys(session->next_crypto->dh_ctx, DH_CLIENT_KEYPAIR, NULL, &client_pubkey); if (rc != SSH_OK) { goto error; } rc = ssh_dh_keypair_get_keys(session->next_crypto->dh_ctx, DH_SERVER_KEYPAIR, NULL, &server_pubkey); if (rc != SSH_OK) { goto error; } rc = ssh_dh_get_parameters(session->next_crypto->dh_ctx, &modulus, &generator); if (rc != SSH_OK) { goto error; } rc = ssh_buffer_pack(buf, "dddBBBB", session->next_crypto->dh_pmin, session->next_crypto->dh_pn, session->next_crypto->dh_pmax, modulus, generator, client_pubkey, server_pubkey); if (rc != SSH_OK) { goto error; } break; #endif /* WITH_GEX */ #ifdef HAVE_ECDH case SSH_KEX_ECDH_SHA2_NISTP256: case SSH_KEX_ECDH_SHA2_NISTP384: case SSH_KEX_ECDH_SHA2_NISTP521: if (session->next_crypto->ecdh_client_pubkey == NULL || session->next_crypto->ecdh_server_pubkey == NULL) { SSH_LOG(SSH_LOG_WARNING, "ECDH parameted missing"); goto error; } rc = ssh_buffer_pack(buf, "SS", session->next_crypto->ecdh_client_pubkey, session->next_crypto->ecdh_server_pubkey); if (rc != SSH_OK) { goto error; } break; #endif #ifdef HAVE_CURVE25519 case SSH_KEX_CURVE25519_SHA256: case SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG: rc = ssh_buffer_pack(buf, "dPdP", CURVE25519_PUBKEY_SIZE, (size_t)CURVE25519_PUBKEY_SIZE, session->next_crypto->curve25519_client_pubkey, CURVE25519_PUBKEY_SIZE, (size_t)CURVE25519_PUBKEY_SIZE, session->next_crypto->curve25519_server_pubkey); if (rc != SSH_OK) { goto error; } break; #endif } rc = ssh_buffer_pack(buf, "B", session->next_crypto->shared_secret); if (rc != SSH_OK) { goto error; } #ifdef DEBUG_CRYPTO ssh_print_hexa("hash buffer", ssh_buffer_get(buf), ssh_buffer_get_len(buf)); #endif switch (session->next_crypto->kex_type) { case SSH_KEX_DH_GROUP1_SHA1: case SSH_KEX_DH_GROUP14_SHA1: #ifdef WITH_GEX case SSH_KEX_DH_GEX_SHA1: #endif /* WITH_GEX */ session->next_crypto->digest_len = SHA_DIGEST_LENGTH; session->next_crypto->digest_type = SSH_KDF_SHA1; session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len); if (session->next_crypto->secret_hash == NULL) { ssh_set_error_oom(session); goto error; } sha1(ssh_buffer_get(buf), ssh_buffer_get_len(buf), session->next_crypto->secret_hash); break; case SSH_KEX_ECDH_SHA2_NISTP256: case SSH_KEX_CURVE25519_SHA256: case SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG: #ifdef WITH_GEX case SSH_KEX_DH_GEX_SHA256: #endif /* WITH_GEX */ session->next_crypto->digest_len = SHA256_DIGEST_LENGTH; session->next_crypto->digest_type = SSH_KDF_SHA256; session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len); if (session->next_crypto->secret_hash == NULL) { ssh_set_error_oom(session); goto error; } sha256(ssh_buffer_get(buf), ssh_buffer_get_len(buf), session->next_crypto->secret_hash); break; case SSH_KEX_ECDH_SHA2_NISTP384: session->next_crypto->digest_len = SHA384_DIGEST_LENGTH; session->next_crypto->digest_type = SSH_KDF_SHA384; session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len); if (session->next_crypto->secret_hash == NULL) { ssh_set_error_oom(session); goto error; } sha384(ssh_buffer_get(buf), ssh_buffer_get_len(buf), session->next_crypto->secret_hash); break; case SSH_KEX_DH_GROUP16_SHA512: case SSH_KEX_DH_GROUP18_SHA512: case SSH_KEX_ECDH_SHA2_NISTP521: session->next_crypto->digest_len = SHA512_DIGEST_LENGTH; session->next_crypto->digest_type = SSH_KDF_SHA512; session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len); if (session->next_crypto->secret_hash == NULL) { ssh_set_error_oom(session); goto error; } sha512(ssh_buffer_get(buf), ssh_buffer_get_len(buf), session->next_crypto->secret_hash); break; } /* During the first kex, secret hash and session ID are equal. However, after * a key re-exchange, a new secret hash is calculated. This hash will not replace * but complement existing session id. */ if (!session->next_crypto->session_id) { session->next_crypto->session_id = malloc(session->next_crypto->digest_len); if (session->next_crypto->session_id == NULL) { ssh_set_error_oom(session); goto error; } memcpy(session->next_crypto->session_id, session->next_crypto->secret_hash, session->next_crypto->digest_len); } #ifdef DEBUG_CRYPTO printf("Session hash: \n"); ssh_print_hexa("secret hash", session->next_crypto->secret_hash, session->next_crypto->digest_len); ssh_print_hexa("session id", session->next_crypto->session_id, session->next_crypto->digest_len); #endif rc = SSH_OK; error: ssh_buffer_free(buf); ssh_buffer_free(client_hash); ssh_buffer_free(server_hash); session->in_hashbuf = NULL; session->out_hashbuf = NULL; ssh_string_free(num); return rc; }