guacamole-server/src/protocols/ssh/ssh_agent.c

220 lines
6.4 KiB
C

/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is libguac-client-ssh.
*
* The Initial Developer of the Original Code is
* Michael Jumper.
* Portions created by the Initial Developer are Copyright (C) 2011
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <libssh2.h>
#include <pthread.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <guacamole/client.h>
#include "client.h"
#include "ssh_agent.h"
#include "ssh_buffer.h"
void ssh_auth_agent_sign(ssh_auth_agent* agent, char* data, int data_length) {
LIBSSH2_CHANNEL* channel = agent->channel;
ssh_key* key = agent->identity;
char sig[4096];
int sig_len;
char buffer[4096];
char* pos = buffer;
/* Sign with key */
sig_len = ssh_key_sign(key, data, data_length, (u_char*) sig);
if (sig_len < 0)
return;
buffer_write_uint32(&pos, 1+4 + 4+7 + 4+sig_len);
buffer_write_byte(&pos, SSH2_AGENT_SIGN_RESPONSE);
buffer_write_uint32(&pos, 4+7 + 4+sig_len);
/* Write key type */
if (key->type == SSH_KEY_RSA)
buffer_write_string(&pos, "ssh-rsa", 7);
else if (key->type == SSH_KEY_DSA)
buffer_write_string(&pos, "ssh-dss", 7);
else
return;
/* Write signature */
buffer_write_string(&pos, sig, sig_len);
libssh2_channel_write(channel, buffer, pos-buffer);
libssh2_channel_flush(channel);
}
void ssh_auth_agent_list_identities(ssh_auth_agent* auth_agent) {
LIBSSH2_CHANNEL* channel = auth_agent->channel;
ssh_key* key = auth_agent->identity;
char buffer[4096];
char* pos = buffer;
buffer_write_uint32(&pos, 1+4
+ key->public_key_length+4
+ sizeof(SSH_AGENT_COMMENT)+3);
buffer_write_byte(&pos, SSH2_AGENT_IDENTITIES_ANSWER);
buffer_write_uint32(&pos, 1);
buffer_write_string(&pos, key->public_key, key->public_key_length);
buffer_write_string(&pos, SSH_AGENT_COMMENT, sizeof(SSH_AGENT_COMMENT)-1);
libssh2_channel_write(channel, buffer, pos-buffer);
libssh2_channel_flush(channel);
}
void ssh_auth_agent_handle_packet(ssh_auth_agent* auth_agent, uint8_t type,
char* data, int data_length) {
switch (type) {
/* List identities */
case SSH2_AGENT_REQUEST_IDENTITIES:
ssh_auth_agent_list_identities(auth_agent);
break;
/* Sign request */
case SSH2_AGENT_SIGN_REQUEST: {
char* pos = data;
int key_blob_length;
int sign_data_length;
char* sign_data;
/* Skip past key, read data, ignore flags */
buffer_read_string(&pos, &key_blob_length);
sign_data = buffer_read_string(&pos, &sign_data_length);
/* Sign given data */
ssh_auth_agent_sign(auth_agent, sign_data, sign_data_length);
break;
}
/* Otherwise, return failure */
default:
libssh2_channel_write(auth_agent->channel,
UNSUPPORTED, sizeof(UNSUPPORTED)-1);
}
}
int ssh_auth_agent_read(ssh_auth_agent* auth_agent) {
LIBSSH2_CHANNEL* channel = auth_agent->channel;
int bytes_read;
if (libssh2_channel_eof(channel))
return -1;
/* Read header if available */
if (auth_agent->buffer_length >= 5) {
uint32_t length =
(((unsigned char*) auth_agent->buffer)[0] << 24)
| (((unsigned char*) auth_agent->buffer)[1] << 16)
| (((unsigned char*) auth_agent->buffer)[2] << 8)
| ((unsigned char*) auth_agent->buffer)[3];
uint8_t type = ((unsigned char*) auth_agent->buffer)[4];
/* If enough data read, call handler, shift data */
if (auth_agent->buffer_length >= length+4) {
ssh_auth_agent_handle_packet(auth_agent, type,
auth_agent->buffer+5, length-1);
auth_agent->buffer_length -= length+4;
memmove(auth_agent->buffer,
auth_agent->buffer+length+4, auth_agent->buffer_length);
return length+4;
}
}
/* Read data into buffer */
bytes_read = libssh2_channel_read(channel,
auth_agent->buffer+auth_agent->buffer_length,
sizeof(auth_agent->buffer)-auth_agent->buffer_length);
/* If unsuccessful, return error */
if (bytes_read < 0)
return bytes_read;
/* Update buffer length */
auth_agent->buffer_length += bytes_read;
return bytes_read;
}
void ssh_auth_agent_callback(LIBSSH2_SESSION *session,
LIBSSH2_CHANNEL *channel, void **abstract) {
/* Get client data */
guac_client* client = (guac_client*) *abstract;
ssh_guac_client_data* client_data = (ssh_guac_client_data*) client->data;
/* Init auth agent */
ssh_auth_agent* auth_agent = malloc(sizeof(ssh_auth_agent));
auth_agent->channel = channel;
auth_agent->identity = client_data->key;
auth_agent->buffer_length = 0;
/* Store auth agent */
client_data->auth_agent = auth_agent;
}