aboutsummaryrefslogtreecommitdiff
path: root/libssh/session.c
blob: dc485ec8b47f39ebd0d69b210ffcb8bb4ba48985 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
/* session.c */
/* contains the non-networking functions ssh_* */
/*
 * Copyright (c) 2005-2008 Aris Adamantiadis
 *
 * This file is part of the SSH Library
 *
 * The SSH Library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * The SSH Library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the SSH Library; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA. */

#include <string.h>
#include <stdlib.h>
#include "libssh/libssh.h"
#include "libssh/priv.h"
#include "libssh/server.h"
#define FIRST_CHANNEL 42 // why not ? it helps to find bugs.

/** \defgroup ssh_session SSH Session
 * \brief functions that manage a session
 */
/** \addtogroup ssh_session
 * @{ */

/** \brief creates a new ssh session
 * \returns new ssh_session pointer
 */
SSH_SESSION *ssh_new() {
    SSH_SESSION *session=malloc(sizeof (SSH_SESSION));
    memset(session,0,sizeof(SSH_SESSION));
    session->next_crypto=crypto_new();
    session->maxchannel=FIRST_CHANNEL;
    session->socket=ssh_socket_new(session);
    session->alive=0;
    session->blocking=1;
    session->log_indent=0;
    session->out_buffer=buffer_new();
    session->in_buffer=buffer_new();
    return session;
}

void ssh_cleanup(SSH_SESSION *session){
	enter_function();
    int i;
    if(session->serverbanner)
        free(session->serverbanner);
    if(session->clientbanner)
        free(session->clientbanner);
    if(session->in_buffer)
        buffer_free(session->in_buffer);
    if(session->out_buffer)
        buffer_free(session->out_buffer);
    if(session->banner)
        free(session->banner);
    if(session->options)
        ssh_options_free(session->options);
    if(session->current_crypto)
        crypto_free(session->current_crypto);
    if(session->next_crypto)
        crypto_free(session->next_crypto);
    if(session->socket)
    	ssh_socket_free(session->socket);
    // delete all channels
    while(session->channels)
        channel_free(session->channels);
    if(session->client_kex.methods)
        for(i=0;i<10;i++)
            if(session->client_kex.methods[i])
                free(session->client_kex.methods[i]);
    if(session->server_kex.methods)
        for(i=0;i<10;++i)
            if(session->server_kex.methods[i])
                free(session->server_kex.methods[i]);
    free(session->client_kex.methods);
    free(session->server_kex.methods);
    if(session->dsa_key)
        private_key_free(session->dsa_key);
    if(session->rsa_key)
        private_key_free(session->rsa_key);
    if(session->ssh_message){
        ssh_message_free(session->ssh_message);
        free(session->ssh_message);
    }
    memset(session,'X',sizeof(SSH_SESSION)); /* burn connection, it could hangs
                                                sensitive datas */
    free(session);
    //leave_function();
}

/** \brief disconnect impolitely from remote host
 * \param session current ssh session
 */
void ssh_silent_disconnect(SSH_SESSION *session){
	enter_function();
    ssh_socket_close(session->socket);
    session->alive=0;
    ssh_disconnect(session);
    //leave_function();
}

/** \brief set the options for the current session
 * \param session ssh session
 * \param options options structure
 * \see ssh_new()
 * \see ssh_options_new()
 */
void ssh_set_options(SSH_SESSION *session, SSH_OPTIONS *options){
    session->options=options;
    session->log_verbosity=options->log_verbosity;
}

/** \brief set the session in blocking/nonblocking mode
 * \param session ssh session
 * \param blocking zero for nonblocking mode
 * \bug nonblocking code is in development and won't work as expected
 */
void ssh_set_blocking(SSH_SESSION *session,int blocking){
    session->blocking=blocking?1:0;
}

/** In case you'd need the file descriptor of the connection
 * to the server/client
 * \brief recover the fd of connection
 * \param session ssh session
 * \return file descriptor of the connection, or -1 if it is
 * not connected
 */

socket_t ssh_get_fd(SSH_SESSION *session){
    return ssh_socket_get_fd(session->socket);
}

/** \brief say to the session it has data to read on the file descriptor without blocking
 * \param session ssh session
 */
void ssh_set_fd_toread(SSH_SESSION *session){
    ssh_socket_set_toread(session->socket);
}

/** \brief say the session it may write to the file descriptor without blocking
 * \param session ssh session
 */
void ssh_set_fd_towrite(SSH_SESSION *session){
    ssh_socket_set_towrite(session->socket);

}

/** \brief say the session it has an exception to catch on the file descriptor
 * \param session ssh session
 */
void ssh_set_fd_except(SSH_SESSION *session){
   ssh_socket_set_except(session->socket);
}

/** \warning I don't remember if this should be internal or not
 */
/* looks if there is data to read on the socket and parse it. */
int ssh_handle_packets(SSH_SESSION *session){
    int w,err,r,i=0;
    enter_function();
    do {
        r=ssh_socket_poll(session->socket,&w,&err);
        if(r<=0){
        	leave_function();
            return r; // error or no data available
        }
        /* if an exception happened, it will be trapped by packet_read() */
        if(packet_read(session)||packet_translate(session)){
            leave_function();
        	return -1;
        }
        packet_parse(session);
        ++i;
    } while(r>0);
    leave_function();
    return r;
}

/** \brief get session status
 * \param session ssh session
 * \returns a bitmask including SSH_CLOSED, SSH_READ_PENDING or SSH_CLOSED_ERROR
 * which respectively means the session is closed, has data to read on the connection socket and session was closed due to an error
 */
int ssh_get_status(SSH_SESSION *session){
    int ret=0;
    int socketstate=ssh_socket_get_status(session->socket);
    if(session->closed)
        ret |= SSH_CLOSED;
    if(socketstate & SSH_READ_PENDING)
        ret |= SSH_READ_PENDING;
    if(session->closed && socketstate & SSH_CLOSED_ERROR)
        ret |= SSH_CLOSED_ERROR;
    return ret;
}

/** \brief get the disconnect message from the server
 * \param session ssh session
 * \return message sent by the server along with the disconnect, or NULL in which case the reason of the disconnect may be found with ssh_get_error.
 * \see ssh_get_error()
 */
const char *ssh_get_disconnect_message(SSH_SESSION *session){
    if(!session->closed)
        ssh_set_error(session,SSH_REQUEST_DENIED,"Connection not closed"
                " yet");
    else if(session->closed_by_except)
        ssh_set_error(session,SSH_REQUEST_DENIED,"Connection closed by "
                "socket error");
    else if(!session->discon_msg)
        ssh_set_error(session,SSH_FATAL,"Connection correctly closed but "
                "no disconnect message");
    else
        return session->discon_msg;
    return NULL;
}

/** \brief get the protocol version of the session
 * \param session ssh session
 * \return 1 or 2, for ssh1 or ssh2
 */
int ssh_get_version(SSH_SESSION *session){
    return session->version;
}

/** @} */