libssh  0.8.3
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 "libssh/priv.h"
24 #include "libssh/kex.h"
25 #include "libssh/packet.h"
26 #include "libssh/pcap.h"
27 #include "libssh/auth.h"
28 #include "libssh/channels.h"
29 #include "libssh/poll.h"
30 
31 /* These are the different states a SSH session can be into its life */
32 enum ssh_session_state_e {
33  SSH_SESSION_STATE_NONE=0,
34  SSH_SESSION_STATE_CONNECTING,
35  SSH_SESSION_STATE_SOCKET_CONNECTED,
36  SSH_SESSION_STATE_BANNER_RECEIVED,
37  SSH_SESSION_STATE_INITIAL_KEX,
38  SSH_SESSION_STATE_KEXINIT_RECEIVED,
39  SSH_SESSION_STATE_DH,
40  SSH_SESSION_STATE_AUTHENTICATING,
41  SSH_SESSION_STATE_AUTHENTICATED,
42  SSH_SESSION_STATE_ERROR,
43  SSH_SESSION_STATE_DISCONNECTED
44 };
45 
46 enum ssh_dh_state_e {
47  DH_STATE_INIT=0,
48  DH_STATE_INIT_SENT,
49  DH_STATE_NEWKEYS_SENT,
50  DH_STATE_FINISHED
51 };
52 
53 enum ssh_pending_call_e {
54  SSH_PENDING_CALL_NONE = 0,
55  SSH_PENDING_CALL_CONNECT,
56  SSH_PENDING_CALL_AUTH_NONE,
57  SSH_PENDING_CALL_AUTH_PASSWORD,
58  SSH_PENDING_CALL_AUTH_OFFER_PUBKEY,
59  SSH_PENDING_CALL_AUTH_PUBKEY,
60  SSH_PENDING_CALL_AUTH_AGENT,
61  SSH_PENDING_CALL_AUTH_KBDINT_INIT,
62  SSH_PENDING_CALL_AUTH_KBDINT_SEND,
63  SSH_PENDING_CALL_AUTH_GSSAPI_MIC
64 };
65 
66 /* libssh calls may block an undefined amount of time */
67 #define SSH_SESSION_FLAG_BLOCKING 1
68 
69 /* Client successfully authenticated */
70 #define SSH_SESSION_FLAG_AUTHENTICATED 2
71 
72 /* codes to use with ssh_handle_packets*() */
73 /* Infinite timeout */
74 #define SSH_TIMEOUT_INFINITE -1
75 /* Use the timeout defined by user if any. Mostly used with new connections */
76 #define SSH_TIMEOUT_USER -2
77 /* Use the default timeout, depending on ssh_is_blocking() */
78 #define SSH_TIMEOUT_DEFAULT -3
79 /* Don't block at all */
80 #define SSH_TIMEOUT_NONBLOCKING 0
81 
82 /* options flags */
83 /* Authentication with *** allowed */
84 #define SSH_OPT_FLAG_PASSWORD_AUTH 0x1
85 #define SSH_OPT_FLAG_PUBKEY_AUTH 0x2
86 #define SSH_OPT_FLAG_KBDINT_AUTH 0x4
87 #define SSH_OPT_FLAG_GSSAPI_AUTH 0x8
88 
89 /* extensions flags */
90 /* server-sig-algs extension */
91 #define SSH_EXT_SIG_RSA_SHA256 0x01
92 #define SSH_EXT_SIG_RSA_SHA512 0x02
93 #define SSH_EXT_ALL SSH_EXT_SIG_RSA_SHA256 | SSH_EXT_SIG_RSA_SHA512
94 
95 /* members that are common to ssh_session and ssh_bind */
97  struct error_struct error;
98  ssh_callbacks callbacks; /* Callbacks to user functions */
99  int log_verbosity; /* verbosity of the log functions */
100 };
101 
103  struct ssh_common_struct common;
104  struct ssh_socket_struct *socket;
105  char *serverbanner;
106  char *clientbanner;
107  int protoversion;
108  int server;
109  int client;
110  int openssh;
111  uint32_t send_seq;
112  uint32_t recv_seq;
113 
114  int connected;
115  /* !=0 when the user got a session handle */
116  int alive;
117  /* two previous are deprecated */
118  /* int auth_service_asked; */
119 
120  /* session flags (SSH_SESSION_FLAG_*) */
121  int flags;
122 
123  /* Extensions negotiated using RFC 8308 */
124  uint32_t extensions;
125 
126  ssh_string banner; /* that's the issue banner from
127  the server */
128  char *discon_msg; /* disconnect message from
129  the remote host */
130  ssh_buffer in_buffer;
131  PACKET in_packet;
132  ssh_buffer out_buffer;
133 
134  /* the states are used by the nonblocking stuff to remember */
135  /* where it was before being interrupted */
136  enum ssh_pending_call_e pending_call_state;
137  enum ssh_session_state_e session_state;
138  int packet_state;
139  enum ssh_dh_state_e dh_handshake_state;
140  enum ssh_channel_request_state_e global_req_state;
141  struct ssh_agent_state_struct *agent_state;
142 
143  struct {
144  struct ssh_auth_auto_state_struct *auto_state;
145  enum ssh_auth_service_state_e service_state;
146  enum ssh_auth_state_e state;
147  uint32_t supported_methods;
148  uint32_t current_method;
149  } auth;
150 
151  /*
152  * RFC 4253, 7.1: if the first_kex_packet_follows flag was set in
153  * the received SSH_MSG_KEXINIT, but the guess was wrong, this
154  * field will be set such that the following guessed packet will
155  * be ignored. Once that packet has been received and ignored,
156  * this field is cleared.
157  */
158  int first_kex_follows_guess_wrong;
159 
160  ssh_buffer in_hashbuf;
161  ssh_buffer out_hashbuf;
162  struct ssh_crypto_struct *current_crypto;
163  struct ssh_crypto_struct *next_crypto; /* next_crypto is going to be used after a SSH2_MSG_NEWKEYS */
164 
165  struct ssh_list *channels; /* linked list of channels */
166  int maxchannel;
167  int exec_channel_opened; /* version 1 only. more
168  info in channels1.c */
169  ssh_agent agent; /* ssh agent */
170 
171 /* keyb interactive data */
172  struct ssh_kbdint_struct *kbdint;
173  struct ssh_gssapi_struct *gssapi;
174 
175  /* server host keys */
176  struct {
177  ssh_key rsa_key;
178  ssh_key dsa_key;
179  ssh_key ecdsa_key;
180  ssh_key ed25519_key;
181  /* The type of host key wanted by client */
182  enum ssh_keytypes_e hostkey;
183  } srv;
184 
185  /* auths accepted by server */
186  struct ssh_list *ssh_message_list; /* list of delayed SSH messages */
187  int (*ssh_message_callback)( struct ssh_session_struct *session, ssh_message msg, void *userdata);
188  void *ssh_message_callback_data;
189  ssh_server_callbacks server_callbacks;
190  void (*ssh_connection_callback)( struct ssh_session_struct *session);
191  struct ssh_packet_callbacks_struct default_packet_callbacks;
192  struct ssh_list *packet_callbacks;
193  struct ssh_socket_callbacks_struct socket_callbacks;
194  ssh_poll_ctx default_poll_ctx;
195  /* options */
196 #ifdef WITH_PCAP
197  ssh_pcap_context pcap_ctx; /* pcap debugging context */
198 #endif
199  struct {
200  struct ssh_list *identity;
201  char *username;
202  char *host;
203  char *bindaddr; /* bind the client to an ip addr */
204  char *sshdir;
205  char *knownhosts;
206  char *global_knownhosts;
207  char *wanted_methods[10];
208  char *pubkey_accepted_types;
209  char *ProxyCommand;
210  char *custombanner;
211  unsigned long timeout; /* seconds */
212  unsigned long timeout_usec;
213  unsigned int port;
214  socket_t fd;
215  int StrictHostKeyChecking;
216  char compressionlevel;
217  char *gss_server_identity;
218  char *gss_client_identity;
219  int gss_delegate_creds;
220  int flags;
221  int nodelay;
222  } opts;
223  /* counters */
224  ssh_counter socket_counter;
225  ssh_counter raw_counter;
226 };
227 
233 typedef int (*ssh_termination_function)(void *user);
234 int ssh_handle_packets(ssh_session session, int timeout);
235 int ssh_handle_packets_termination(ssh_session session, int timeout,
236  ssh_termination_function fct, void *user);
237 void ssh_socket_exception_callback(int code, int errno_code, void *user);
238 
239 #endif /* SESSION_H_ */
Definition: pki.h:42
Definition: callbacks.h:378
Definition: auth.h:37
Definition: crypto.h:84
Definition: agent.h:73
Definition: callbacks.h:142
Definition: messages.h:84
Definition: poll.c:76
Definition: callbacks.h:530
Definition: session.h:102
Definition: gssapi.c:48
Definition: packet.h:29
Definition: auth.c:966
Definition: misc.h:38
Definition: callbacks.h:304
Definition: string.h:29
Definition: auth.c:828
Definition: priv.h:219
Definition: socket.c:76
Definition: session.h:96
Definition: buffer.c:47
Definition: libssh.h:108