release/src/router/dropbear/session.h

   1 /*
   2  * Dropbear - a SSH2 server
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE. */
  24
  25 #ifndef _SESSION_H_
  26 #define _SESSION_H_
  27
  28 #include "includes.h"
  29 #include "options.h"
  30 #include "buffer.h"
  31 #include "signkey.h"
  32 #include "kex.h"
  33 #include "auth.h"
  34 #include "channel.h"
  35 #include "queue.h"
  36 #include "listener.h"
  37 #include "packet.h"
  38 #include "tcpfwd.h"
  39 #include "chansession.h"
  40 #include "dbutil.h"
  41
  42 extern int sessinitdone; /* Is set to 0 somewhere */
  43 extern int exitflag;
  44
  45 void common_session_init(int sock_in, int sock_out);
  46 void session_loop(void(*loophandler)());
  47 void session_cleanup();
  48 void send_session_identification();
  49 void send_msg_ignore();
  50 void ignore_recv_response();
  51
  52 void update_channel_prio();
  53
  54 const char* get_user_shell();
  55 void fill_passwd(const char* username);
  56
  57 /* Server */
  58 void svr_session(int sock, int childpipe);
  59 void svr_dropbear_exit(int exitcode, const char* format, va_list param) ATTRIB_NORETURN;
  60 void svr_dropbear_log(int priority, const char* format, va_list param);
  61
  62 /* Client */
  63 void cli_session(int sock_in, int sock_out);
  64 void cleantext(unsigned char* dirtytext);
  65
  66 /* crypto parameters that are stored individually for transmit and receive */
  67 struct key_context_directional {
  68         const struct dropbear_cipher *algo_crypt;
  69         const struct dropbear_cipher_mode *crypt_mode;
  70         const struct dropbear_hash *algo_mac;
  71         int hash_index; /* lookup for libtomcrypt */
  72         int algo_comp; /* compression */
  73 #ifndef DISABLE_ZLIB
  74         z_streamp zstream;
  75 #endif
  76         /* actual keys */
  77         union {
  78                 symmetric_CBC cbc;
  79 #ifdef DROPBEAR_ENABLE_CTR_MODE
  80                 symmetric_CTR ctr;
  81 #endif
  82         } cipher_state;
  83         unsigned char mackey[MAX_MAC_LEN];
  84         int valid;
  85 };
  86
  87 struct key_context {
  88
  89         struct key_context_directional recv;
  90         struct key_context_directional trans;
  91
  92         const struct dropbear_kex *algo_kex;
  93         int algo_hostkey;
  94
  95         int allow_compress; /* whether compression has started (useful in
  96                                                         zlib@openssh.com delayed compression case) */
  97 };
  98
  99 struct packetlist;
 100 struct packetlist {
 101         struct packetlist *next;
 102         buffer * payload;
 103 };
 104
 105 struct sshsession {
 106
 107         /* Is it a client or server? */
 108         unsigned char isserver;
 109
 110         int sock_in;
 111         int sock_out;
 112
 113         /* remotehost will be initially NULL as we delay
 114          * reading the remote version string. it will be set
 115          * by the time any recv_() packet methods are called */
 116         unsigned char *remoteident;
 117
 118         int maxfd; /* the maximum file descriptor to check with select() */
 119
 120
 121         /* Packet buffers/values etc */
 122         buffer *writepayload; /* Unencrypted payload to write - this is used
 123                                                          throughout the code, as handlers fill out this
 124                                                          buffer with the packet to send. */
 125         struct Queue writequeue; /* A queue of encrypted packets to send */
 126         buffer *readbuf; /* From the wire, decrypted in-place */
 127         buffer *payload; /* Post-decompression, the actual SSH packet */
 128         unsigned int transseq, recvseq; /* Sequence IDs */
 129
 130         /* Packet-handling flags */
 131         const packettype * packettypes; /* Packet handler mappings for this
 132                                                                                 session, see process-packet.c */
 133
 134         unsigned dataallowed : 1; /* whether we can send data packets or we are in
 135                                                                  the middle of a KEX or something */
 136
 137         unsigned char requirenext; /* byte indicating what packets we require next,
 138                                                                          or 0x00 for any.  */
 139
 140         unsigned char ignorenext; /* whether to ignore the next packet,
 141                                                                  used for kex_follows stuff */
 142
 143         unsigned char lastpacket; /* What the last received packet type was */
 144
 145         int signal_pipe[2]; /* stores endpoints of a self-pipe used for
 146                                                    race-free signal handling */
 147
 148         /* time of the last packet send/receive, for keepalive. Not real-world clock */
 149         time_t last_packet_time_keepalive_sent;
 150         time_t last_packet_time_keepalive_recv;
 151         time_t last_packet_time_any_sent;
 152
 153         time_t last_packet_time_idle; /* time of the last packet transmission or receive, for
 154                                                                 idle timeout purposes so ignores SSH_MSG_IGNORE
 155                                                                 or responses to keepalives. Not real-world clock */
 156
 157
 158         /* KEX/encryption related */
 159         struct KEXState kexstate;
 160         struct key_context *keys;
 161         struct key_context *newkeys;
 162         buffer *session_id; /* this is the hash from the first kex */
 163         /* The below are used temporarily during kex, are freed after use */
 164         mp_int * dh_K; /* SSH_MSG_KEXDH_REPLY and sending SSH_MSH_NEWKEYS */
 165         buffer *hash; /* the session hash */
 166         buffer* kexhashbuf; /* session hash buffer calculated from various packets*/
 167         buffer* transkexinit; /* the kexinit packet we send should be kept so we
 168                                                          can add it to the hash when generating keys */
 169
 170         /* Enables/disables compression */
 171         algo_type *compress_algos;
 172
 173         /* a list of queued replies that should be sent after a KEX has
 174            concluded (ie, while dataallowed was unset)*/
 175         struct packetlist *reply_queue_head, *reply_queue_tail;
 176
 177         void(*remoteclosed)(); /* A callback to handle closure of the
 178                                                                           remote connection */
 179
 180         void(*extra_session_cleanup)(); /* client or server specific cleanup */
 181         void(*send_kex_first_guess)();
 182
 183         struct AuthState authstate; /* Common amongst client and server, since most
 184                                                                    struct elements are common */
 185
 186         /* Channel related */
 187         struct Channel ** channels; /* these pointers may be null */
 188         unsigned int chansize; /* the number of Channel*s allocated for channels */
 189         unsigned int chancount; /* the number of Channel*s in use */
 190         const struct ChanType **chantypes; /* The valid channel types */
 191         int channel_signal_pending; /* Flag set by sigchld handler */
 192
 193         /* TCP priority level for the main "port 22" tcp socket */
 194         enum dropbear_prio socket_prio;
 195
 196         /* TCP forwarding - where manage listeners */
 197         struct Listener ** listeners;
 198         unsigned int listensize;
 199
 200         /* Whether to allow binding to privileged ports (<1024). This doesn't
 201          * really belong here, but nowhere else fits nicely */
 202         int allowprivport;
 203
 204 };
 205
 206 struct serversession {
 207
 208         /* Server specific options */
 209         int childpipe; /* kept open until we successfully authenticate */
 210         /* userauth */
 211
 212         struct ChildPid * childpids; /* array of mappings childpid<->channel */
 213         unsigned int childpidsize;
 214
 215         /* Used to avoid a race in the exit returncode handling - see
 216          * svr-chansession.c for details */
 217         struct exitinfo lastexit;
 218
 219         /* The numeric address they connected from, used for logging */
 220         char * addrstring;
 221
 222         /* The resolved remote address, used for lastlog etc */
 223         char *remotehost;
 224
 225         time_t connect_time; /* time the connection was established
 226                                                         (cleared after auth once we're not
 227                                                         respecting AUTH_TIMEOUT any more).
 228                                                         A monotonic time, not realworld */
 229
 230 #ifdef USE_VFORK
 231         pid_t server_pid;
 232 #endif
 233
 234 };
 235
 236 typedef enum {
 237         KEX_NOTHING,
 238         KEXINIT_RCVD,
 239         KEXDH_INIT_SENT,
 240         KEXDONE
 241 } cli_kex_state;
 242
 243 typedef enum {
 244         STATE_NOTHING,
 245         USERAUTH_WAIT,
 246         USERAUTH_REQ_SENT,
 247         USERAUTH_FAIL_RCVD,
 248         USERAUTH_SUCCESS_RCVD,
 249         SESSION_RUNNING
 250 } cli_state;
 251
 252 struct clientsession {
 253
 254         /* XXX - move these to kexstate? */
 255         struct kex_dh_param *dh_param;
 256         struct kex_ecdh_param *ecdh_param;
 257         struct kex_curve25519_param *curve25519_param;
 258         const struct dropbear_kex *param_kex_algo; /* KEX algorithm corresponding to current dh_e and dh_x */
 259
 260         cli_kex_state kex_state; /* Used for progressing KEX */
 261         cli_state state; /* Used to progress auth/channelsession etc */
 262         unsigned donefirstkex : 1; /* Set when we set sentnewkeys, never reset */
 263
 264         int tty_raw_mode; /* Whether we're in raw mode (and have to clean up) */
 265         struct termios saved_tio;
 266         int stdincopy;
 267         int stdinflags;
 268         int stdoutcopy;
 269         int stdoutflags;
 270         int stderrcopy;
 271         int stderrflags;
 272
 273         /* for escape char handling */
 274         int last_char;
 275
 276         int winchange; /* Set to 1 when a windowchange signal happens */
 277
 278         int lastauthtype; /* either AUTH_TYPE_PUBKEY or AUTH_TYPE_PASSWORD,
 279                                                  for the last type of auth we tried */
 280         int ignore_next_auth_response;
 281 #ifdef ENABLE_CLI_INTERACT_AUTH
 282         int auth_interact_failed; /* flag whether interactive auth can still
 283                                                                  be used */
 284         int interact_request_received; /* flag whether we've received an
 285                                                                           info request from the server for
 286                                                                           interactive auth.*/
 287
 288         int cipher_none_after_auth; /* Set to 1 if the user requested "none"
 289                                                                    auth */
 290 #endif
 291         sign_key *lastprivkey;
 292
 293         int retval; /* What the command exit status was - we emulate it */
 294 #if 0
 295         TODO
 296         struct AgentkeyList *agentkeys; /* Keys to use for public-key auth */
 297 #endif
 298
 299 };
 300
 301 /* Global structs storing the state */
 302 extern struct sshsession ses;
 303
 304 #ifdef DROPBEAR_SERVER
 305 extern struct serversession svr_ses;
 306 #endif /* DROPBEAR_SERVER */
 307
 308 #ifdef DROPBEAR_CLIENT
 309 extern struct clientsession cli_ses;
 310 #endif /* DROPBEAR_CLIENT */
 311
 312 #endif /* _SESSION_H_ */