Key exchange currently done asynchronously
Fixed an important bug in packet buffering (two packets received in the same recv would'nt be processed correctly)
Этот коммит содержится в:
Aris Adamantiadis
родитель
964d5f88cc
Коммит
c92f54102e
@ -121,6 +121,8 @@ SSH_PACKET_CALLBACK(ssh_packet_ignore_callback);
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int ssh_send_banner(ssh_session session, int is_server);
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void ssh_connection_callback(ssh_session session);
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SSH_PACKET_CALLBACK(ssh_packet_dh_reply);
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SSH_PACKET_CALLBACK(ssh_packet_newkeys);
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/* config.c */
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int ssh_config_parse_file(ssh_session session, const char *filename);
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280
libssh/client.c
280
libssh/client.c
@ -248,13 +248,144 @@ int ssh_send_banner(ssh_session session, int server) {
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enum ssh_dh_state_e {
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DH_STATE_INIT,
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DH_STATE_INIT_TO_SEND,
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DH_STATE_INIT_SENT,
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DH_STATE_NEWKEYS_TO_SEND,
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DH_STATE_NEWKEYS_SENT,
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DH_STATE_FINISHED
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};
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SSH_PACKET_CALLBACK(ssh_packet_dh_reply){
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ssh_string f = NULL;
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ssh_string pubkey = NULL;
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ssh_string signature = NULL;
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(void)type;
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(void)user;
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ssh_log(session,SSH_LOG_PROTOCOL,"Received SSH_KEXDH_REPLY");
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if(session->session_state!= SSH_SESSION_STATE_DH &&
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session->dh_handshake_state != DH_STATE_INIT_SENT){
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ssh_set_error(session,SSH_FATAL,"ssh_packet_dh_reply called in wrong state : %d:%d",
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session->session_state,session->dh_handshake_state);
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goto error;
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}
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pubkey = buffer_get_ssh_string(packet);
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if (pubkey == NULL){
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ssh_set_error(session,SSH_FATAL, "No public key in packet");
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goto error;
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}
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dh_import_pubkey(session, pubkey);
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f = buffer_get_ssh_string(packet);
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if (f == NULL) {
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ssh_set_error(session,SSH_FATAL, "No F number in packet");
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goto error;
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}
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if (dh_import_f(session, f) < 0) {
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ssh_set_error(session, SSH_FATAL, "Cannot import f number");
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goto error;
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}
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string_burn(f);
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string_free(f);
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f=NULL;
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signature = buffer_get_ssh_string(packet);
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if (signature == NULL) {
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ssh_set_error(session, SSH_FATAL, "No signature in packet");
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goto error;
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}
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session->dh_server_signature = signature;
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if (dh_build_k(session) < 0) {
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ssh_set_error(session, SSH_FATAL, "Cannot build k number");
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goto error;
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}
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/* Send the MSG_NEWKEYS */
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if (buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) {
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goto error;
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}
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packet_send(session);
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ssh_log(session, SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent");
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session->dh_handshake_state = DH_STATE_NEWKEYS_SENT;
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return SSH_PACKET_USED;
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error:
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session->session_state=SSH_SESSION_STATE_ERROR;
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return SSH_PACKET_USED;
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}
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SSH_PACKET_CALLBACK(ssh_packet_newkeys){
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ssh_string signature = NULL;
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int rc;
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(void)packet;
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(void)user;
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(void)type;
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ssh_log(session, SSH_LOG_PROTOCOL, "Received SSH_MSG_NEWKEYS");
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if(session->session_state!= SSH_SESSION_STATE_DH &&
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session->dh_handshake_state != DH_STATE_NEWKEYS_SENT){
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ssh_set_error(session,SSH_FATAL,"ssh_packet_newkeys called in wrong state : %d:%d",
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session->session_state,session->dh_handshake_state);
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goto error;
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}
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rc = make_sessionid(session);
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if (rc != SSH_OK) {
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goto error;
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}
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/*
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* Set the cryptographic functions for the next crypto
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* (it is needed for generate_session_keys for key lenghts)
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*/
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if (crypt_set_algorithms(session)) {
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goto error;
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}
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if (generate_session_keys(session) < 0) {
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goto error;
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}
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/* Verify the host's signature. FIXME do it sooner */
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signature = session->dh_server_signature;
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session->dh_server_signature = NULL;
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if (signature_verify(session, signature)) {
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goto error;
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}
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/* forget it for now ... */
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string_burn(signature);
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string_free(signature);
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signature=NULL;
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/*
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* Once we got SSH2_MSG_NEWKEYS we can switch next_crypto and
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* current_crypto
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*/
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if (session->current_crypto) {
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crypto_free(session->current_crypto);
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session->current_crypto=NULL;
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}
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/* FIXME later, include a function to change keys */
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session->current_crypto = session->next_crypto;
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session->next_crypto = crypto_new();
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if (session->next_crypto == NULL) {
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ssh_set_error_oom(session);
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goto error;
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}
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session->dh_handshake_state = DH_STATE_FINISHED;
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ssh_connection_callback(session);
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return SSH_PACKET_USED;
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error:
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session->session_state=SSH_SESSION_STATE_ERROR;
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return SSH_PACKET_USED;
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}
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/** @internal
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* @brief launches the DH handshake state machine
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* @param session session handle
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* @returns SSH_OK or SSH_ERROR
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* @warning this function returning is no proof that DH handshake is
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* completed
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*/
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static int dh_handshake(ssh_session session) {
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ssh_string e = NULL;
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ssh_string f = NULL;
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@ -294,143 +425,25 @@ static int dh_handshake(ssh_session session) {
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goto error;
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}
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session->dh_handshake_state = DH_STATE_INIT_TO_SEND;
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case DH_STATE_INIT_TO_SEND:
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rc = packet_flush(session, 0);
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if (rc != SSH_OK) {
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goto error;
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}
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session->dh_handshake_state = DH_STATE_INIT_SENT;
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case DH_STATE_INIT_SENT:
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rc = packet_wait(session, SSH2_MSG_KEXDH_REPLY, 1);
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if (rc != SSH_OK) {
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goto error;
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}
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pubkey = buffer_get_ssh_string(session->in_buffer);
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if (pubkey == NULL){
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ssh_set_error(session,SSH_FATAL, "No public key in packet");
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rc = SSH_ERROR;
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goto error;
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}
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dh_import_pubkey(session, pubkey);
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f = buffer_get_ssh_string(session->in_buffer);
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if (f == NULL) {
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ssh_set_error(session,SSH_FATAL, "No F number in packet");
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rc = SSH_ERROR;
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goto error;
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}
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if (dh_import_f(session, f) < 0) {
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ssh_set_error(session, SSH_FATAL, "Cannot import f number");
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rc = SSH_ERROR;
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goto error;
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}
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string_burn(f);
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string_free(f);
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f=NULL;
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signature = buffer_get_ssh_string(session->in_buffer);
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if (signature == NULL) {
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ssh_set_error(session, SSH_FATAL, "No signature in packet");
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rc = SSH_ERROR;
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goto error;
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}
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session->dh_server_signature = signature;
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if (dh_build_k(session) < 0) {
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ssh_set_error(session, SSH_FATAL, "Cannot build k number");
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rc = SSH_ERROR;
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goto error;
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}
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/* Send the MSG_NEWKEYS */
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if (buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) {
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rc = SSH_ERROR;
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goto error;
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}
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rc = packet_send(session);
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if (rc == SSH_ERROR) {
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goto error;
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}
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session->dh_handshake_state = DH_STATE_NEWKEYS_TO_SEND;
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case DH_STATE_NEWKEYS_TO_SEND:
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rc = packet_flush(session, 0);
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if (rc != SSH_OK) {
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goto error;
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}
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ssh_log(session, SSH_LOG_RARE, "SSH_MSG_NEWKEYS sent\n");
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session->dh_handshake_state = DH_STATE_NEWKEYS_SENT;
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/* wait until ssh_packet_dh_reply is called */
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break;
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case DH_STATE_NEWKEYS_SENT:
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rc = packet_wait(session, SSH2_MSG_NEWKEYS, 1);
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if (rc != SSH_OK) {
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goto error;
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}
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ssh_log(session, SSH_LOG_RARE, "Got SSH_MSG_NEWKEYS\n");
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rc = make_sessionid(session);
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if (rc != SSH_OK) {
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goto error;
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}
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/*
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* Set the cryptographic functions for the next crypto
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* (it is needed for generate_session_keys for key lenghts)
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*/
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if (crypt_set_algorithms(session)) {
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rc = SSH_ERROR;
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goto error;
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}
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if (generate_session_keys(session) < 0) {
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rc = SSH_ERROR;
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goto error;
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}
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/* Verify the host's signature. FIXME do it sooner */
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signature = session->dh_server_signature;
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session->dh_server_signature = NULL;
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if (signature_verify(session, signature)) {
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rc = SSH_ERROR;
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goto error;
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}
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/* forget it for now ... */
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string_burn(signature);
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string_free(signature);
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signature=NULL;
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/*
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* Once we got SSH2_MSG_NEWKEYS we can switch next_crypto and
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* current_crypto
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*/
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if (session->current_crypto) {
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crypto_free(session->current_crypto);
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session->current_crypto=NULL;
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}
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/* FIXME later, include a function to change keys */
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session->current_crypto = session->next_crypto;
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session->next_crypto = crypto_new();
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if (session->next_crypto == NULL) {
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rc = SSH_ERROR;
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goto error;
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}
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session->dh_handshake_state = DH_STATE_FINISHED;
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leave_function();
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/* wait until ssh_packet_newkeys is calles */
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break;
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case DH_STATE_FINISHED:
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leave_function();
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return SSH_OK;
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default:
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ssh_set_error(session, SSH_FATAL, "Invalid state in dh_handshake(): %d",
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session->dh_handshake_state);
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leave_function();
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return SSH_ERROR;
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}
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/* not reached */
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leave_function();
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return SSH_AGAIN;
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error:
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if(e != NULL){
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string_burn(e);
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@ -565,6 +578,7 @@ void ssh_connection_callback(ssh_session session){
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session->session_state=SSH_SESSION_STATE_AUTHENTICATING;
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break;
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}
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break;
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case SSH_SESSION_STATE_KEXINIT_RECEIVED:
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set_status(session,0.6);
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ssh_list_kex(session, &session->server_kex);
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@ -576,15 +590,13 @@ void ssh_connection_callback(ssh_session session){
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}
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set_status(session,0.8);
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session->session_state=SSH_SESSION_STATE_DH;
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break;
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case SSH_SESSION_STATE_DH:
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if (dh_handshake(session) < 0) {
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if (dh_handshake(session) == SSH_ERROR) {
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goto error;
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}
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case SSH_SESSION_STATE_DH:
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if(session->dh_handshake_state==DH_STATE_FINISHED){
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set_status(session,1.0);
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session->connected = 1;
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break;
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session->session_state=SSH_SESSION_STATE_AUTHENTICATING;
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}
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break;
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@ -661,7 +673,9 @@ int ssh_connect(ssh_session session) {
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ssh_log(session,SSH_LOG_PACKET,"ssh_connect: Actual state : %d",session->session_state);
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}
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leave_function();
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return 0;
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if(session->session_state == SSH_SESSION_STATE_ERROR)
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return SSH_ERROR;
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return SSH_OK;
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}
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/**
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@ -57,10 +57,10 @@ ssh_packet_callback default_packet_handlers[]= {
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NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, // 7-19
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ssh_packet_kexinit, //#define SSH2_MSG_KEXINIT 20
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NULL, //#define SSH2_MSG_NEWKEYS 21
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ssh_packet_newkeys, //#define SSH2_MSG_NEWKEYS 21
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NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, //22-29
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NULL, //#define SSH2_MSG_KEXDH_INIT 30 SSH2_MSG_KEX_DH_GEX_REQUEST_OLD 30
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NULL, // #define SSH2_MSG_KEXDH_REPLY 31 SSH2_MSG_KEX_DH_GEX_GROUP 31
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ssh_packet_dh_reply, // #define SSH2_MSG_KEXDH_REPLY 31 SSH2_MSG_KEX_DH_GEX_GROUP 31
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NULL, //#define SSH2_MSG_KEX_DH_GEX_INIT 32
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NULL, //#define SSH2_MSG_KEX_DH_GEX_REPLY 33
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NULL, //#define SSH2_MSG_KEX_DH_GEX_REQUEST 34
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@ -260,10 +260,18 @@ int ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user)
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/* execute callbacks */
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ssh_packet_process(session, session->in_packet.type);
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session->packet_state = PACKET_STATE_INIT;
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if(processed < receivedlen){
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/* Handle a potential packet left in socket buffer */
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ssh_log(session,SSH_LOG_PACKET,"Processing %" PRIdS " bytes left in socket buffer",
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receivedlen-processed);
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rc = ssh_packet_socket_callback((char *)data + processed,
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receivedlen - processed,user);
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processed += rc;
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}
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leave_function();
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return processed;
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case PACKET_STATE_PROCESSING:
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ssh_log(session, SSH_LOG_PACKET, "Nested packet processing. Delaying.");
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ssh_log(session, SSH_LOG_RARE, "Nested packet processing. Delaying.");
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return 0;
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}
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