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session.h
/*
* This file is part of the SSH Library
*
* Copyright (c) 2009 by Aris Adamantiadis
*
* This 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.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef SESSION_H_
#define SESSION_H_
#include <stdbool.h>
#include "libssh/priv.h"
#include "libssh/callbacks.h"
#include "libssh/kex.h"
#include "libssh/packet.h"
#include "libssh/pcap.h"
#include "libssh/auth.h"
#include "libssh/channels.h"
#include "libssh/poll.h"
#include "libssh/config.h"
#include "libssh/misc.h"
/* These are the different states a SSH session can be into its life */
enum ssh_session_state_e {
SSH_SESSION_STATE_NONE=0,
SSH_SESSION_STATE_CONNECTING,
SSH_SESSION_STATE_SOCKET_CONNECTED,
SSH_SESSION_STATE_BANNER_RECEIVED,
SSH_SESSION_STATE_INITIAL_KEX,
SSH_SESSION_STATE_KEXINIT_RECEIVED,
SSH_SESSION_STATE_DH,
SSH_SESSION_STATE_AUTHENTICATING,
SSH_SESSION_STATE_AUTHENTICATED,
SSH_SESSION_STATE_ERROR,
SSH_SESSION_STATE_DISCONNECTED
};
enum ssh_dh_state_e {
DH_STATE_INIT=0,
DH_STATE_GROUP_SENT,
DH_STATE_REQUEST_SENT,
DH_STATE_INIT_SENT,
DH_STATE_NEWKEYS_SENT,
DH_STATE_FINISHED
};
enum ssh_pending_call_e {
SSH_PENDING_CALL_NONE = 0,
SSH_PENDING_CALL_CONNECT,
SSH_PENDING_CALL_AUTH_NONE,
SSH_PENDING_CALL_AUTH_PASSWORD,
SSH_PENDING_CALL_AUTH_OFFER_PUBKEY,
SSH_PENDING_CALL_AUTH_PUBKEY,
SSH_PENDING_CALL_AUTH_AGENT,
SSH_PENDING_CALL_AUTH_KBDINT_INIT,
SSH_PENDING_CALL_AUTH_KBDINT_SEND,
SSH_PENDING_CALL_AUTH_GSSAPI_MIC
};
/* libssh calls may block an undefined amount of time */
#define SSH_SESSION_FLAG_BLOCKING 1
/* Client successfully authenticated */
#define SSH_SESSION_FLAG_AUTHENTICATED 2
/* The KEXINIT message can be sent first by either of the parties so this flag
* indicates that the message was already sent to make sure it is sent and avoid
* sending it twice during key exchange to simplify the state machine. */
#define SSH_SESSION_FLAG_KEXINIT_SENT 4
/* The current SSH2 session implements the "strict KEX" feature and should behave
* differently on SSH2_MSG_NEWKEYS. */
#define SSH_SESSION_FLAG_KEX_STRICT 0x0010
/* Unexpected packets have been sent while the session was still unencrypted */
#define SSH_SESSION_FLAG_KEX_TAINTED 0x0020
/* codes to use with ssh_handle_packets*() */
/* Infinite timeout */
#define SSH_TIMEOUT_INFINITE -1
/* Use the timeout defined by user if any. Mostly used with new connections */
#define SSH_TIMEOUT_USER -2
/* Use the default timeout, depending on ssh_is_blocking() */
#define SSH_TIMEOUT_DEFAULT -3
/* Don't block at all */
#define SSH_TIMEOUT_NONBLOCKING 0
/* options flags */
/* Authentication with *** allowed */
#define SSH_OPT_FLAG_PASSWORD_AUTH 0x1
#define SSH_OPT_FLAG_PUBKEY_AUTH 0x2
#define SSH_OPT_FLAG_KBDINT_AUTH 0x4
#define SSH_OPT_FLAG_GSSAPI_AUTH 0x8
/* Escape expansion of different variables */
#define SSH_OPT_EXP_FLAG_KNOWNHOSTS 0x1
#define SSH_OPT_EXP_FLAG_GLOBAL_KNOWNHOSTS 0x2
#define SSH_OPT_EXP_FLAG_PROXYCOMMAND 0x4
#define SSH_OPT_EXP_FLAG_IDENTITY 0x8
/* extensions flags */
/* negotiation enabled */
#define SSH_EXT_NEGOTIATION 0x01
/* server-sig-algs extension */
#define SSH_EXT_SIG_RSA_SHA256 0x02
#define SSH_EXT_SIG_RSA_SHA512 0x04
/* members that are common to ssh_session and ssh_bind */
struct ssh_common_struct {
struct error_struct error;
ssh_callbacks callbacks; /* Callbacks to user functions */
int log_verbosity; /* verbosity of the log functions */
};
struct ssh_session_struct {
struct ssh_common_struct common;
struct ssh_socket_struct *socket;
char *serverbanner;
char *clientbanner;
int protoversion;
int server;
int client;
int openssh;
uint32_t send_seq;
uint32_t recv_seq;
struct ssh_timestamp last_rekey_time;
int connected;
/* !=0 when the user got a session handle */
int alive;
/* two previous are deprecated */
/* int auth_service_asked; */
/* session flags (SSH_SESSION_FLAG_*) */
int flags;
/* Extensions negotiated using RFC 8308 */
uint32_t extensions;
ssh_string banner; /* that's the issue banner from the server */
char *peer_discon_msg; /* disconnect message from the remote host */
char *disconnect_message; /* disconnect message to be set */
ssh_buffer in_buffer;
PACKET in_packet;
ssh_buffer out_buffer;
struct ssh_list *out_queue; /* This list is used for delaying packets
when rekeying is required */
/* the states are used by the nonblocking stuff to remember */
/* where it was before being interrupted */
enum ssh_pending_call_e pending_call_state;
enum ssh_session_state_e session_state;
enum ssh_packet_state_e packet_state;
enum ssh_dh_state_e dh_handshake_state;
enum ssh_channel_request_state_e global_req_state;
struct ssh_agent_state_struct *agent_state;
struct {
struct ssh_auth_auto_state_struct *auto_state;
enum ssh_auth_service_state_e service_state;
enum ssh_auth_state_e state;
uint32_t supported_methods;
uint32_t current_method;
} auth;
/* Sending this flag before key exchange to save one round trip during the
* key exchange. This might make sense on high-latency connections.
* So far internal only for testing. Usable only on the client side --
* there is no key exchange method that would start with server message */
bool send_first_kex_follows;
/*
* RFC 4253, 7.1: if the first_kex_packet_follows flag was set in
* the received SSH_MSG_KEXINIT, but the guess was wrong, this
* field will be set such that the following guessed packet will
* be ignored on the receiving side. Once that packet has been received and
* ignored, this field is cleared.
* On the sending side, this is set after we got peer KEXINIT message and we
* need to resend the initial message of the negotiated KEX algorithm.
*/
bool first_kex_follows_guess_wrong;
ssh_buffer in_hashbuf;
ssh_buffer out_hashbuf;
struct ssh_crypto_struct *current_crypto;
/* next_crypto is going to be used after a SSH2_MSG_NEWKEYS */
struct ssh_crypto_struct *next_crypto;
struct ssh_list *channels; /* linked list of channels */
uint32_t maxchannel;
ssh_agent agent; /* ssh agent */
/* keyboard interactive data */
struct ssh_kbdint_struct *kbdint;
struct ssh_gssapi_struct *gssapi;
/* server host keys */
struct {
ssh_key rsa_key;
ssh_key dsa_key;
ssh_key ecdsa_key;
ssh_key ed25519_key;
/* The type of host key wanted by client */
enum ssh_keytypes_e hostkey;
enum ssh_digest_e hostkey_digest;
} srv;
/* auths accepted by server */
struct ssh_list *ssh_message_list; /* list of delayed SSH messages */
int (*ssh_message_callback)(struct ssh_session_struct *session,
ssh_message msg, void *userdata);
void *ssh_message_callback_data;
ssh_server_callbacks server_callbacks;
void (*ssh_connection_callback)( struct ssh_session_struct *session);
struct ssh_packet_callbacks_struct default_packet_callbacks;
struct ssh_list *packet_callbacks;
struct ssh_socket_callbacks_struct socket_callbacks;
ssh_poll_ctx default_poll_ctx;
/* options */
#ifdef WITH_PCAP
ssh_pcap_context pcap_ctx; /* pcap debugging context */
#endif
struct {
struct ssh_list *identity;
struct ssh_list *identity_non_exp;
char *username;
char *host;
char *bindaddr; /* bind the client to an ip addr */
char *sshdir;
char *knownhosts;
char *global_knownhosts;
char *wanted_methods[SSH_KEX_METHODS];
char *pubkey_accepted_types;
char *ProxyCommand;
char *custombanner;
char *moduli_file;
char *agent_socket;
unsigned long timeout; /* seconds */
unsigned long timeout_usec;
uint16_t port;
socket_t fd;
int StrictHostKeyChecking;
char compressionlevel;
char *gss_server_identity;
char *gss_client_identity;
int gss_delegate_creds;
int flags;
int exp_flags;
int nodelay;
bool config_processed;
uint8_t options_seen[SOC_MAX];
uint64_t rekey_data;
uint32_t rekey_time;
int rsa_min_size;
} opts;
/* counters */
ssh_counter socket_counter;
ssh_counter raw_counter;
};
typedef int (*ssh_termination_function)(void *user);
int ssh_handle_packets(ssh_session session, int timeout);
int ssh_handle_packets_termination(ssh_session session,
int timeout,
ssh_termination_function fct,
void *user);
void ssh_socket_exception_callback(int code, int errno_code, void *user);
#endif /* SESSION_H_ */
error_struct
Definition priv.h:263
packet_struct
Definition packet.h:29
ssh_agent_state_struct
Definition auth.c:865
ssh_agent_struct
Definition agent.h:77
ssh_auth_auto_state_struct
Definition auth.c:1004
ssh_buffer_struct
Definition buffer.c:48
ssh_callbacks_struct
Definition callbacks.h:144
ssh_common_struct
Definition session.h:121
ssh_counter_struct
Definition libssh.h:95
ssh_crypto_struct
Definition crypto.h:106
ssh_gssapi_struct
Definition gssapi.c:48
ssh_kbdint_struct
Definition auth.h:41
ssh_key_struct
Definition pki.h:54
ssh_list
Definition misc.h:45
ssh_message_struct
Definition messages.h:85
ssh_packet_callbacks_struct
Definition callbacks.h:535
ssh_poll_ctx_struct
Definition poll.c:76
ssh_server_callbacks_struct
Definition callbacks.h:306
ssh_session_struct
Definition session.h:127
ssh_socket_callbacks_struct
Definition callbacks.h:383
ssh_socket_struct
Definition socket.c:85
ssh_string_struct
Definition string.h:33
ssh_timestamp
Definition misc.h:55