libssh  0.9.6
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/kex.h"
27 #include "libssh/packet.h"
28 #include "libssh/pcap.h"
29 #include "libssh/auth.h"
30 #include "libssh/channels.h"
31 #include "libssh/poll.h"
32 #include "libssh/config.h"
33 #include "libssh/misc.h"
34 
35 /* These are the different states a SSH session can be into its life */
36 enum ssh_session_state_e {
37  SSH_SESSION_STATE_NONE=0,
38  SSH_SESSION_STATE_CONNECTING,
39  SSH_SESSION_STATE_SOCKET_CONNECTED,
40  SSH_SESSION_STATE_BANNER_RECEIVED,
41  SSH_SESSION_STATE_INITIAL_KEX,
42  SSH_SESSION_STATE_KEXINIT_RECEIVED,
43  SSH_SESSION_STATE_DH,
44  SSH_SESSION_STATE_AUTHENTICATING,
45  SSH_SESSION_STATE_AUTHENTICATED,
46  SSH_SESSION_STATE_ERROR,
47  SSH_SESSION_STATE_DISCONNECTED
48 };
49 
50 enum ssh_dh_state_e {
51  DH_STATE_INIT=0,
52  DH_STATE_GROUP_SENT,
53  DH_STATE_REQUEST_SENT,
54  DH_STATE_INIT_SENT,
55  DH_STATE_NEWKEYS_SENT,
56  DH_STATE_FINISHED
57 };
58 
59 enum ssh_pending_call_e {
60  SSH_PENDING_CALL_NONE = 0,
61  SSH_PENDING_CALL_CONNECT,
62  SSH_PENDING_CALL_AUTH_NONE,
63  SSH_PENDING_CALL_AUTH_PASSWORD,
64  SSH_PENDING_CALL_AUTH_OFFER_PUBKEY,
65  SSH_PENDING_CALL_AUTH_PUBKEY,
66  SSH_PENDING_CALL_AUTH_AGENT,
67  SSH_PENDING_CALL_AUTH_KBDINT_INIT,
68  SSH_PENDING_CALL_AUTH_KBDINT_SEND,
69  SSH_PENDING_CALL_AUTH_GSSAPI_MIC
70 };
71 
72 /* libssh calls may block an undefined amount of time */
73 #define SSH_SESSION_FLAG_BLOCKING 1
74 
75 /* Client successfully authenticated */
76 #define SSH_SESSION_FLAG_AUTHENTICATED 2
77 
78 /* The current SSH2 session implements the "strict KEX" feature and should behave
79  * differently on SSH2_MSG_NEWKEYS. */
80 #define SSH_SESSION_FLAG_KEX_STRICT 0x0010
81 /* Unexpected packets have been sent while the session was still unencrypted */
82 #define SSH_SESSION_FLAG_KEX_TAINTED 0x0020
83 
84 /* codes to use with ssh_handle_packets*() */
85 /* Infinite timeout */
86 #define SSH_TIMEOUT_INFINITE -1
87 /* Use the timeout defined by user if any. Mostly used with new connections */
88 #define SSH_TIMEOUT_USER -2
89 /* Use the default timeout, depending on ssh_is_blocking() */
90 #define SSH_TIMEOUT_DEFAULT -3
91 /* Don't block at all */
92 #define SSH_TIMEOUT_NONBLOCKING 0
93 
94 /* options flags */
95 /* Authentication with *** allowed */
96 #define SSH_OPT_FLAG_PASSWORD_AUTH 0x1
97 #define SSH_OPT_FLAG_PUBKEY_AUTH 0x2
98 #define SSH_OPT_FLAG_KBDINT_AUTH 0x4
99 #define SSH_OPT_FLAG_GSSAPI_AUTH 0x8
100 
101 /* extensions flags */
102 /* negotiation enabled */
103 #define SSH_EXT_NEGOTIATION 0x01
104 /* server-sig-algs extension */
105 #define SSH_EXT_SIG_RSA_SHA256 0x02
106 #define SSH_EXT_SIG_RSA_SHA512 0x04
107 
108 /* members that are common to ssh_session and ssh_bind */
110  struct error_struct error;
111  ssh_callbacks callbacks; /* Callbacks to user functions */
112  int log_verbosity; /* verbosity of the log functions */
113 };
114 
116  struct ssh_common_struct common;
117  struct ssh_socket_struct *socket;
118  char *serverbanner;
119  char *clientbanner;
120  int protoversion;
121  int server;
122  int client;
123  int openssh;
124  uint32_t send_seq;
125  uint32_t recv_seq;
126  struct ssh_timestamp last_rekey_time;
127 
128  int connected;
129  /* !=0 when the user got a session handle */
130  int alive;
131  /* two previous are deprecated */
132  /* int auth_service_asked; */
133 
134  /* session flags (SSH_SESSION_FLAG_*) */
135  int flags;
136 
137  /* Extensions negotiated using RFC 8308 */
138  uint32_t extensions;
139 
140  ssh_string banner; /* that's the issue banner from
141  the server */
142  char *discon_msg; /* disconnect message from
143  the remote host */
144  ssh_buffer in_buffer;
145  PACKET in_packet;
146  ssh_buffer out_buffer;
147  struct ssh_list *out_queue; /* This list is used for delaying packets
148  when rekeying is required */
149 
150  /* the states are used by the nonblocking stuff to remember */
151  /* where it was before being interrupted */
152  enum ssh_pending_call_e pending_call_state;
153  enum ssh_session_state_e session_state;
154  enum ssh_packet_state_e packet_state;
155  enum ssh_dh_state_e dh_handshake_state;
156  enum ssh_channel_request_state_e global_req_state;
157  struct ssh_agent_state_struct *agent_state;
158 
159  struct {
160  struct ssh_auth_auto_state_struct *auto_state;
161  enum ssh_auth_service_state_e service_state;
162  enum ssh_auth_state_e state;
163  uint32_t supported_methods;
164  uint32_t current_method;
165  } auth;
166 
167  /*
168  * RFC 4253, 7.1: if the first_kex_packet_follows flag was set in
169  * the received SSH_MSG_KEXINIT, but the guess was wrong, this
170  * field will be set such that the following guessed packet will
171  * be ignored. Once that packet has been received and ignored,
172  * this field is cleared.
173  */
174  int first_kex_follows_guess_wrong;
175 
176  ssh_buffer in_hashbuf;
177  ssh_buffer out_hashbuf;
178  struct ssh_crypto_struct *current_crypto;
179  struct ssh_crypto_struct *next_crypto; /* next_crypto is going to be used after a SSH2_MSG_NEWKEYS */
180 
181  struct ssh_list *channels; /* linked list of channels */
182  int maxchannel;
183  ssh_agent agent; /* ssh agent */
184 
185 /* keyb interactive data */
186  struct ssh_kbdint_struct *kbdint;
187  struct ssh_gssapi_struct *gssapi;
188 
189  /* server host keys */
190  struct {
191  ssh_key rsa_key;
192  ssh_key dsa_key;
193  ssh_key ecdsa_key;
194  ssh_key ed25519_key;
195  /* The type of host key wanted by client */
196  enum ssh_keytypes_e hostkey;
197  enum ssh_digest_e hostkey_digest;
198  } srv;
199 
200  /* auths accepted by server */
201  struct ssh_list *ssh_message_list; /* list of delayed SSH messages */
202  int (*ssh_message_callback)( struct ssh_session_struct *session, ssh_message msg, void *userdata);
203  void *ssh_message_callback_data;
204  ssh_server_callbacks server_callbacks;
205  void (*ssh_connection_callback)( struct ssh_session_struct *session);
206  struct ssh_packet_callbacks_struct default_packet_callbacks;
207  struct ssh_list *packet_callbacks;
208  struct ssh_socket_callbacks_struct socket_callbacks;
209  ssh_poll_ctx default_poll_ctx;
210  /* options */
211 #ifdef WITH_PCAP
212  ssh_pcap_context pcap_ctx; /* pcap debugging context */
213 #endif
214  struct {
215  struct ssh_list *identity;
216  char *username;
217  char *host;
218  char *bindaddr; /* bind the client to an ip addr */
219  char *sshdir;
220  char *knownhosts;
221  char *global_knownhosts;
222  char *wanted_methods[SSH_KEX_METHODS];
223  char *pubkey_accepted_types;
224  char *ProxyCommand;
225  char *custombanner;
226  unsigned long timeout; /* seconds */
227  unsigned long timeout_usec;
228  unsigned int port;
229  socket_t fd;
230  int StrictHostKeyChecking;
231  char compressionlevel;
232  char *gss_server_identity;
233  char *gss_client_identity;
234  int gss_delegate_creds;
235  int flags;
236  int nodelay;
237  bool config_processed;
238  uint8_t options_seen[SOC_MAX];
239  uint64_t rekey_data;
240  uint32_t rekey_time;
241  } opts;
242  /* counters */
243  ssh_counter socket_counter;
244  ssh_counter raw_counter;
245 };
246 
252 typedef int (*ssh_termination_function)(void *user);
253 int ssh_handle_packets(ssh_session session, int timeout);
254 int ssh_handle_packets_termination(ssh_session session,
255  long timeout,
256  ssh_termination_function fct,
257  void *user);
258 void ssh_socket_exception_callback(int code, int errno_code, void *user);
259 
260 #endif /* SESSION_H_ */
Definition: pki.h:50
Definition: callbacks.h:378
Definition: auth.h:37
Definition: crypto.h:106
Definition: agent.h:73
Definition: callbacks.h:142
Definition: messages.h:84
Definition: poll.c:76
Definition: callbacks.h:530
Definition: session.h:115
Definition: gssapi.c:48
Definition: packet.h:29
Definition: auth.c:971
Definition: misc.h:39
Definition: callbacks.h:304
Definition: string.h:29
Definition: auth.c:833
Definition: misc.h:49
Definition: priv.h:254
Definition: socket.c:78
Definition: session.h:109
Definition: buffer.c:47
Definition: libssh.h:93