mirror of
https://git.libssh.org/projects/libssh.git
synced 2026-02-04 12:20:42 +09:00
Add more error checks to dh_handshake().
git-svn-id: svn+ssh://svn.berlios.de/svnroot/repos/libssh/trunk@485 7dcaeef0-15fb-0310-b436-a5af3365683c
This commit is contained in:
Andreas Schneider
283
libssh/client.c
283
libssh/client.c
@@ -174,122 +174,177 @@ int ssh_send_banner(SSH_SESSION *session, int server) {
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#define DH_STATE_NEWKEYS_TO_SEND 3
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#define DH_STATE_NEWKEYS_SENT 4
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#define DH_STATE_FINISHED 5
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static int dh_handshake(SSH_SESSION *session){
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STRING *e,*f,*pubkey,*signature;
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int ret;
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enter_function();
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switch(session->dh_handshake_state){
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case DH_STATE_INIT:
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buffer_add_u8(session->out_buffer,SSH2_MSG_KEXDH_INIT);
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dh_generate_x(session);
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dh_generate_e(session);
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e=dh_get_e(session);
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buffer_add_ssh_string(session->out_buffer,e);
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ret=packet_send(session);
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free(e);
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session->dh_handshake_state=DH_STATE_INIT_TO_SEND;
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if(ret==SSH_ERROR){
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leave_function();
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return ret;
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}
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case DH_STATE_INIT_TO_SEND:
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ret=packet_flush(session,0);
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if(ret!=SSH_OK){
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leave_function();
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return ret; // SSH_ERROR or SSH_AGAIN
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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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ret=packet_wait(session,SSH2_MSG_KEXDH_REPLY,1);
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if(ret != SSH_OK){
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leave_function();
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return ret;
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}
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pubkey=buffer_get_ssh_string(session->in_buffer);
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if(!pubkey){
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ssh_set_error(session,SSH_FATAL,"No public key in packet");
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leave_function();
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return SSH_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){
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ssh_set_error(session,SSH_FATAL,"No F number in packet");
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leave_function();
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return SSH_ERROR;
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}
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dh_import_f(session,f);
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free(f);
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if(!(signature=buffer_get_ssh_string(session->in_buffer))){
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ssh_set_error(session,SSH_FATAL,"No signature in packet");
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leave_function();
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return SSH_ERROR;
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}
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session->dh_server_signature=signature;
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dh_build_k(session);
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// send the MSG_NEWKEYS
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buffer_add_u8(session->out_buffer,SSH2_MSG_NEWKEYS);
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packet_send(session);
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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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ret=packet_flush(session,0);
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if(ret != SSH_OK){
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leave_function();
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return ret;
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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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case DH_STATE_NEWKEYS_SENT:
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ret=packet_wait(session,SSH2_MSG_NEWKEYS,1);
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if(ret != SSH_OK){
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leave_function();
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return ret;
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}
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ssh_log(session, SSH_LOG_RARE, "Got SSH_MSG_NEWKEYS\n");
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ret = make_sessionid(session);
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if (ret != SSH_OK) {
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leave_function();
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return SSH_ERROR;
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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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if(crypt_set_algorithms(session)){
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leave_function();
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return SSH_ERROR;
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}
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generate_session_keys(session);
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/* verify the host's signature. XXX 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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free(signature);
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leave_function();
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return SSH_ERROR;
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}
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free(signature); /* forget it for now ... */
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/* once we got SSH2_MSG_NEWKEYS we can switch next_crypto and current_crypto */
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if(session->current_crypto)
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crypto_free(session->current_crypto);
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/* XXX later, include a function to change keys */
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session->current_crypto=session->next_crypto;
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static int dh_handshake(SSH_SESSION *session) {
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STRING *e = NULL;
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STRING *f = NULL;
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STRING *pubkey = NULL;
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STRING *signature = NULL;
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int rc = SSH_ERROR;
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session->next_crypto = crypto_new();
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if (session->next_crypto == NULL) {
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leave_function();
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return SSH_ERROR;
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}
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enter_function();
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session->dh_handshake_state=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",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_ERROR;
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switch (session->dh_handshake_state) {
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case DH_STATE_INIT:
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if (buffer_add_u8(session->out_buffer, SSH2_MSG_KEXDH_INIT) < 0) {
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goto error;
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}
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dh_generate_x(session);
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dh_generate_e(session);
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e = dh_get_e(session);
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if (e == NULL) {
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goto error;
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}
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if (buffer_add_ssh_string(session->out_buffer, e) < 0) {
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goto error;
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}
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string_burn(e);
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string_free(e);
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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_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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dh_import_f(session, f);
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string_burn(f);
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string_free(f);
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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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dh_build_k(session);
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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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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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generate_session_keys(session);
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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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/*
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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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}
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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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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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error:
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string_burn(e);
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string_free(e);
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string_burn(f);
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string_free(f);
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string_burn(pubkey);
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string_free(pubkey);
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string_burn(signature);
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string_free(signature);
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leave_function();
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return rc;
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}
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int ssh_service_request(SSH_SESSION *session, const char *service) {
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