libssh  0.10.4
The SSH library
session.h
1 /*
2  * This file is part of the SSH Library
3  *
4  * Copyright (c) 2009 by Aris Adamantiadis
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef SESSION_H_
22 #define SESSION_H_
23 #include <stdbool.h>
24 
25 #include "libssh/priv.h"
26 #include "libssh/callbacks.h"
27 #include "libssh/kex.h"
28 #include "libssh/packet.h"
29 #include "libssh/pcap.h"
30 #include "libssh/auth.h"
31 #include "libssh/channels.h"
32 #include "libssh/poll.h"
33 #include "libssh/config.h"
34 #include "libssh/misc.h"
35 
36 /* These are the different states a SSH session can be into its life */
37 enum ssh_session_state_e {
38  SSH_SESSION_STATE_NONE=0,
39  SSH_SESSION_STATE_CONNECTING,
40  SSH_SESSION_STATE_SOCKET_CONNECTED,
41  SSH_SESSION_STATE_BANNER_RECEIVED,
42  SSH_SESSION_STATE_INITIAL_KEX,
43  SSH_SESSION_STATE_KEXINIT_RECEIVED,
44  SSH_SESSION_STATE_DH,
45  SSH_SESSION_STATE_AUTHENTICATING,
46  SSH_SESSION_STATE_AUTHENTICATED,
47  SSH_SESSION_STATE_ERROR,
48  SSH_SESSION_STATE_DISCONNECTED
49 };
50 
51 enum ssh_dh_state_e {
52  DH_STATE_INIT=0,
53  DH_STATE_GROUP_SENT,
54  DH_STATE_REQUEST_SENT,
55  DH_STATE_INIT_SENT,
56  DH_STATE_NEWKEYS_SENT,
57  DH_STATE_FINISHED
58 };
59 
60 enum ssh_pending_call_e {
61  SSH_PENDING_CALL_NONE = 0,
62  SSH_PENDING_CALL_CONNECT,
63  SSH_PENDING_CALL_AUTH_NONE,
64  SSH_PENDING_CALL_AUTH_PASSWORD,
65  SSH_PENDING_CALL_AUTH_OFFER_PUBKEY,
66  SSH_PENDING_CALL_AUTH_PUBKEY,
67  SSH_PENDING_CALL_AUTH_AGENT,
68  SSH_PENDING_CALL_AUTH_KBDINT_INIT,
69  SSH_PENDING_CALL_AUTH_KBDINT_SEND,
70  SSH_PENDING_CALL_AUTH_GSSAPI_MIC
71 };
72 
73 /* libssh calls may block an undefined amount of time */
74 #define SSH_SESSION_FLAG_BLOCKING 1
75 
76 /* Client successfully authenticated */
77 #define SSH_SESSION_FLAG_AUTHENTICATED 2
78 
79 /* codes to use with ssh_handle_packets*() */
80 /* Infinite timeout */
81 #define SSH_TIMEOUT_INFINITE -1
82 /* Use the timeout defined by user if any. Mostly used with new connections */
83 #define SSH_TIMEOUT_USER -2
84 /* Use the default timeout, depending on ssh_is_blocking() */
85 #define SSH_TIMEOUT_DEFAULT -3
86 /* Don't block at all */
87 #define SSH_TIMEOUT_NONBLOCKING 0
88 
89 /* options flags */
90 /* Authentication with *** allowed */
91 #define SSH_OPT_FLAG_PASSWORD_AUTH 0x1
92 #define SSH_OPT_FLAG_PUBKEY_AUTH 0x2
93 #define SSH_OPT_FLAG_KBDINT_AUTH 0x4
94 #define SSH_OPT_FLAG_GSSAPI_AUTH 0x8
95 
96 /* extensions flags */
97 /* negotiation enabled */
98 #define SSH_EXT_NEGOTIATION 0x01
99 /* server-sig-algs extension */
100 #define SSH_EXT_SIG_RSA_SHA256 0x02
101 #define SSH_EXT_SIG_RSA_SHA512 0x04
102 
103 /* members that are common to ssh_session and ssh_bind */
105  struct error_struct error;
106  ssh_callbacks callbacks; /* Callbacks to user functions */
107  int log_verbosity; /* verbosity of the log functions */
108 };
109 
111  struct ssh_common_struct common;
112  struct ssh_socket_struct *socket;
113  char *serverbanner;
114  char *clientbanner;
115  int protoversion;
116  int server;
117  int client;
118  int openssh;
119  uint32_t send_seq;
120  uint32_t recv_seq;
121  struct ssh_timestamp last_rekey_time;
122 
123  int connected;
124  /* !=0 when the user got a session handle */
125  int alive;
126  /* two previous are deprecated */
127  /* int auth_service_asked; */
128 
129  /* session flags (SSH_SESSION_FLAG_*) */
130  int flags;
131 
132  /* Extensions negotiated using RFC 8308 */
133  uint32_t extensions;
134 
135  ssh_string banner; /* that's the issue banner from
136  the server */
137  char *discon_msg; /* disconnect message from
138  the remote host */
139  char *disconnect_message; /* disconnect message to be set */
140  ssh_buffer in_buffer;
141  PACKET in_packet;
142  ssh_buffer out_buffer;
143  struct ssh_list *out_queue; /* This list is used for delaying packets
144  when rekeying is required */
145 
146  /* the states are used by the nonblocking stuff to remember */
147  /* where it was before being interrupted */
148  enum ssh_pending_call_e pending_call_state;
149  enum ssh_session_state_e session_state;
150  enum ssh_packet_state_e packet_state;
151  enum ssh_dh_state_e dh_handshake_state;
152  enum ssh_channel_request_state_e global_req_state;
153  struct ssh_agent_state_struct *agent_state;
154 
155  struct {
156  struct ssh_auth_auto_state_struct *auto_state;
157  enum ssh_auth_service_state_e service_state;
158  enum ssh_auth_state_e state;
159  uint32_t supported_methods;
160  uint32_t current_method;
161  } auth;
162 
163  /*
164  * RFC 4253, 7.1: if the first_kex_packet_follows flag was set in
165  * the received SSH_MSG_KEXINIT, but the guess was wrong, this
166  * field will be set such that the following guessed packet will
167  * be ignored. Once that packet has been received and ignored,
168  * this field is cleared.
169  */
170  int first_kex_follows_guess_wrong;
171 
172  ssh_buffer in_hashbuf;
173  ssh_buffer out_hashbuf;
174  struct ssh_crypto_struct *current_crypto;
175  struct ssh_crypto_struct *next_crypto; /* next_crypto is going to be used after a SSH2_MSG_NEWKEYS */
176 
177  struct ssh_list *channels; /* linked list of channels */
178  uint32_t maxchannel;
179  ssh_agent agent; /* ssh agent */
180 
181 /* keyb interactive data */
182  struct ssh_kbdint_struct *kbdint;
183  struct ssh_gssapi_struct *gssapi;
184 
185  /* server host keys */
186  struct {
187  ssh_key rsa_key;
188  ssh_key dsa_key;
189  ssh_key ecdsa_key;
190  ssh_key ed25519_key;
191  /* The type of host key wanted by client */
192  enum ssh_keytypes_e hostkey;
193  enum ssh_digest_e hostkey_digest;
194  } srv;
195 
196  /* auths accepted by server */
197  struct ssh_list *ssh_message_list; /* list of delayed SSH messages */
198  int (*ssh_message_callback)( struct ssh_session_struct *session, ssh_message msg, void *userdata);
199  void *ssh_message_callback_data;
200  ssh_server_callbacks server_callbacks;
201  void (*ssh_connection_callback)( struct ssh_session_struct *session);
202  struct ssh_packet_callbacks_struct default_packet_callbacks;
203  struct ssh_list *packet_callbacks;
204  struct ssh_socket_callbacks_struct socket_callbacks;
205  ssh_poll_ctx default_poll_ctx;
206  /* options */
207 #ifdef WITH_PCAP
208  ssh_pcap_context pcap_ctx; /* pcap debugging context */
209 #endif
210  struct {
211  struct ssh_list *identity;
212  char *username;
213  char *host;
214  char *bindaddr; /* bind the client to an ip addr */
215  char *sshdir;
216  char *knownhosts;
217  char *global_knownhosts;
218  char *wanted_methods[SSH_KEX_METHODS];
219  char *pubkey_accepted_types;
220  char *ProxyCommand;
221  char *custombanner;
222  char *moduli_file;
223  char *agent_socket;
224  unsigned long timeout; /* seconds */
225  unsigned long timeout_usec;
226  uint16_t port;
227  socket_t fd;
228  int StrictHostKeyChecking;
229  char compressionlevel;
230  char *gss_server_identity;
231  char *gss_client_identity;
232  int gss_delegate_creds;
233  int flags;
234  int nodelay;
235  bool config_processed;
236  uint8_t options_seen[SOC_MAX];
237  uint64_t rekey_data;
238  uint32_t rekey_time;
239  int rsa_min_size;
240  } opts;
241  /* counters */
242  ssh_counter socket_counter;
243  ssh_counter raw_counter;
244 };
245 
251 typedef int (*ssh_termination_function)(void *user);
252 int ssh_handle_packets(ssh_session session, int timeout);
253 int ssh_handle_packets_termination(ssh_session session,
254  int timeout,
255  ssh_termination_function fct,
256  void *user);
257 void ssh_socket_exception_callback(int code, int errno_code, void *user);
258 
259 #endif /* SESSION_H_ */
Definition: priv.h:259
Definition: packet.h:29
Definition: auth.c:864
Definition: agent.h:73
Definition: auth.c:1003
Definition: buffer.c:47
Definition: callbacks.h:142
Definition: session.h:104
Definition: libssh.h:95
Definition: crypto.h:106
Definition: gssapi.c:48
Definition: auth.h:37
Definition: pki.h:54
Definition: misc.h:39
Definition: messages.h:85
Definition: callbacks.h:533
Definition: poll.c:76
Definition: callbacks.h:304
Definition: session.h:110
Definition: callbacks.h:381
Definition: socket.c:87
Definition: string.h:29
Definition: misc.h:49