crypto/openssh/channels.h

   1 /* $OpenBSD: channels.h,v 1.130 2017/09/21 19:16:53 markus Exp $ */
   2
   3 /*
   4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   6  *                    All rights reserved
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  */
  14 /*
  15  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #ifndef CHANNEL_H
  39 #define CHANNEL_H
  40
  41 /* Definitions for channel types. */
  42 #define SSH_CHANNEL_X11_LISTENER        1       /* Listening for inet X11 conn. */
  43 #define SSH_CHANNEL_PORT_LISTENER       2       /* Listening on a port. */
  44 #define SSH_CHANNEL_OPENING             3       /* waiting for confirmation */
  45 #define SSH_CHANNEL_OPEN                4       /* normal open two-way channel */
  46 #define SSH_CHANNEL_CLOSED              5       /* waiting for close confirmation */
  47 #define SSH_CHANNEL_AUTH_SOCKET         6       /* authentication socket */
  48 #define SSH_CHANNEL_X11_OPEN            7       /* reading first X11 packet */
  49 #define SSH_CHANNEL_LARVAL              10      /* larval session */
  50 #define SSH_CHANNEL_RPORT_LISTENER      11      /* Listening to a R-style port  */
  51 #define SSH_CHANNEL_CONNECTING          12
  52 #define SSH_CHANNEL_DYNAMIC             13
  53 #define SSH_CHANNEL_ZOMBIE              14      /* Almost dead. */
  54 #define SSH_CHANNEL_MUX_LISTENER        15      /* Listener for mux conn. */
  55 #define SSH_CHANNEL_MUX_CLIENT          16      /* Conn. to mux slave */
  56 #define SSH_CHANNEL_ABANDONED           17      /* Abandoned session, eg mux */
  57 #define SSH_CHANNEL_UNIX_LISTENER       18      /* Listening on a domain socket. */
  58 #define SSH_CHANNEL_RUNIX_LISTENER      19      /* Listening to a R-style domain socket. */
  59 #define SSH_CHANNEL_MUX_PROXY           20      /* proxy channel for mux-slave */
  60 #define SSH_CHANNEL_RDYNAMIC_OPEN       21      /* reverse SOCKS, parsing request */
  61 #define SSH_CHANNEL_RDYNAMIC_FINISH     22      /* reverse SOCKS, finishing connect */
  62 #define SSH_CHANNEL_MAX_TYPE            23
  63
  64 #define CHANNEL_CANCEL_PORT_STATIC      -1
  65
  66 struct ssh;
  67 struct Channel;
  68 typedef struct Channel Channel;
  69 struct fwd_perm_list;
  70
  71 typedef void channel_open_fn(struct ssh *, int, int, void *);
  72 typedef void channel_callback_fn(struct ssh *, int, void *);
  73 typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int);
  74 typedef void channel_filter_cleanup_fn(struct ssh *, int, void *);
  75 typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *,
  76     u_char **, size_t *);
  77
  78 /* Channel success/failure callbacks */
  79 typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *);
  80 typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *);
  81 struct channel_confirm {
  82         TAILQ_ENTRY(channel_confirm) entry;
  83         channel_confirm_cb *cb;
  84         channel_confirm_abandon_cb *abandon_cb;
  85         void *ctx;
  86 };
  87 TAILQ_HEAD(channel_confirms, channel_confirm);
  88
  89 /* Context for non-blocking connects */
  90 struct channel_connect {
  91         char *host;
  92         int port;
  93         struct addrinfo *ai, *aitop;
  94 };
  95
  96 /* Callbacks for mux channels back into client-specific code */
  97 typedef int mux_callback_fn(struct ssh *, struct Channel *);
  98
  99 struct Channel {
 100         int     type;           /* channel type/state */
 101         int     self;           /* my own channel identifier */
 102         uint32_t remote_id;     /* channel identifier for remote peer */
 103         int     have_remote_id; /* non-zero if remote_id is valid */
 104
 105         u_int   istate;         /* input from channel (state of receive half) */
 106         u_int   ostate;         /* output to channel  (state of transmit half) */
 107         int     flags;          /* close sent/rcvd */
 108         int     rfd;            /* read fd */
 109         int     wfd;            /* write fd */
 110         int     efd;            /* extended fd */
 111         int     sock;           /* sock fd */
 112         int     ctl_chan;       /* control channel (multiplexed connections) */
 113         int     isatty;         /* rfd is a tty */
 114 #ifdef _AIX
 115         int     wfd_isatty;     /* wfd is a tty */
 116 #endif
 117         int     client_tty;     /* (client) TTY has been requested */
 118         int     force_drain;    /* force close on iEOF */
 119         time_t  notbefore;      /* Pause IO until deadline (time_t) */
 120         int     delayed;        /* post-select handlers for newly created
 121                                  * channels are delayed until the first call
 122                                  * to a matching pre-select handler.
 123                                  * this way post-select handlers are not
 124                                  * accidentally called if a FD gets reused */
 125         struct sshbuf *input;   /* data read from socket, to be sent over
 126                                  * encrypted connection */
 127         struct sshbuf *output;  /* data received over encrypted connection for
 128                                  * send on socket */
 129         struct sshbuf *extended;
 130
 131         char    *path;
 132                 /* path for unix domain sockets, or host name for forwards */
 133         int     listening_port; /* port being listened for forwards */
 134         char   *listening_addr; /* addr being listened for forwards */
 135         int     host_port;      /* remote port to connect for forwards */
 136         char   *remote_name;    /* remote hostname */
 137
 138         u_int   remote_window;
 139         u_int   remote_maxpacket;
 140         u_int   local_window;
 141         u_int   local_window_max;
 142         u_int   local_consumed;
 143         u_int   local_maxpacket;
 144         int     extended_usage;
 145         int     single_connection;
 146
 147         char   *ctype;          /* type */
 148
 149         /* callback */
 150         channel_open_fn         *open_confirm;
 151         void                    *open_confirm_ctx;
 152         channel_callback_fn     *detach_user;
 153         int                     detach_close;
 154         struct channel_confirms status_confirms;
 155
 156         /* filter */
 157         channel_infilter_fn     *input_filter;
 158         channel_outfilter_fn    *output_filter;
 159         void                    *filter_ctx;
 160         channel_filter_cleanup_fn *filter_cleanup;
 161
 162         /* keep boundaries */
 163         int                     datagram;
 164
 165         /* non-blocking connect */
 166         /* XXX make this a pointer so the structure can be opaque */
 167         struct channel_connect  connect_ctx;
 168
 169         /* multiplexing protocol hook, called for each packet received */
 170         mux_callback_fn         *mux_rcb;
 171         void                    *mux_ctx;
 172         int                     mux_pause;
 173         int                     mux_downstream_id;
 174 };
 175
 176 #define CHAN_EXTENDED_IGNORE            0
 177 #define CHAN_EXTENDED_READ              1
 178 #define CHAN_EXTENDED_WRITE             2
 179
 180 /* default window/packet sizes for tcp/x11-fwd-channel */
 181 #define CHAN_SES_PACKET_DEFAULT (32*1024)
 182 #define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
 183 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
 184 #define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
 185 #define CHAN_X11_PACKET_DEFAULT (16*1024)
 186 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
 187
 188 /* possible input states */
 189 #define CHAN_INPUT_OPEN                 0
 190 #define CHAN_INPUT_WAIT_DRAIN           1
 191 #define CHAN_INPUT_WAIT_OCLOSE          2
 192 #define CHAN_INPUT_CLOSED               3
 193
 194 /* possible output states */
 195 #define CHAN_OUTPUT_OPEN                0
 196 #define CHAN_OUTPUT_WAIT_DRAIN          1
 197 #define CHAN_OUTPUT_WAIT_IEOF           2
 198 #define CHAN_OUTPUT_CLOSED              3
 199
 200 #define CHAN_CLOSE_SENT                 0x01
 201 #define CHAN_CLOSE_RCVD                 0x02
 202 #define CHAN_EOF_SENT                   0x04
 203 #define CHAN_EOF_RCVD                   0x08
 204 #define CHAN_LOCAL                      0x10
 205
 206 /* Read buffer size */
 207 #define CHAN_RBUF       (16*1024)
 208
 209 /* Hard limit on number of channels */
 210 #define CHANNELS_MAX_CHANNELS   (16*1024)
 211
 212 /* check whether 'efd' is still in use */
 213 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 214         (c->extended_usage == CHAN_EXTENDED_READ && \
 215         (c->efd != -1 || \
 216         sshbuf_len(c->extended) > 0))
 217 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 218         (c->extended_usage == CHAN_EXTENDED_WRITE && \
 219         c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
 220         sshbuf_len(c->extended) > 0))
 221
 222 /* Add channel management structures to SSH transport instance */
 223 void channel_init_channels(struct ssh *ssh);
 224
 225 /* channel management */
 226
 227 Channel *channel_by_id(struct ssh *, int);
 228 Channel *channel_by_remote_id(struct ssh *, u_int);
 229 Channel *channel_lookup(struct ssh *, int);
 230 Channel *channel_new(struct ssh *, char *, int, int, int, int,
 231             u_int, u_int, int, char *, int);
 232 void     channel_set_fds(struct ssh *, int, int, int, int, int,
 233             int, int, u_int);
 234 void     channel_free(struct ssh *, Channel *);
 235 void     channel_free_all(struct ssh *);
 236 void     channel_stop_listening(struct ssh *);
 237
 238 void     channel_send_open(struct ssh *, int);
 239 void     channel_request_start(struct ssh *, int, char *, int);
 240 void     channel_register_cleanup(struct ssh *, int,
 241             channel_callback_fn *, int);
 242 void     channel_register_open_confirm(struct ssh *, int,
 243             channel_open_fn *, void *);
 244 void     channel_register_filter(struct ssh *, int, channel_infilter_fn *,
 245             channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
 246 void     channel_register_status_confirm(struct ssh *, int,
 247             channel_confirm_cb *, channel_confirm_abandon_cb *, void *);
 248 void     channel_cancel_cleanup(struct ssh *, int);
 249 int      channel_close_fd(struct ssh *, int *);
 250 void     channel_send_window_changes(struct ssh *);
 251
 252 /* mux proxy support */
 253
 254 int      channel_proxy_downstream(struct ssh *, Channel *mc);
 255 int      channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *);
 256
 257 /* protocol handler */
 258
 259 int      channel_input_data(int, u_int32_t, struct ssh *);
 260 int      channel_input_extended_data(int, u_int32_t, struct ssh *);
 261 int      channel_input_ieof(int, u_int32_t, struct ssh *);
 262 int      channel_input_oclose(int, u_int32_t, struct ssh *);
 263 int      channel_input_open_confirmation(int, u_int32_t, struct ssh *);
 264 int      channel_input_open_failure(int, u_int32_t, struct ssh *);
 265 int      channel_input_port_open(int, u_int32_t, struct ssh *);
 266 int      channel_input_window_adjust(int, u_int32_t, struct ssh *);
 267 int      channel_input_status_confirm(int, u_int32_t, struct ssh *);
 268
 269 /* file descriptor handling (read/write) */
 270
 271 void     channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *,
 272              u_int*, time_t*);
 273 void     channel_after_select(struct ssh *, fd_set *, fd_set *);
 274 void     channel_output_poll(struct ssh *);
 275
 276 int      channel_not_very_much_buffered_data(struct ssh *);
 277 void     channel_close_all(struct ssh *);
 278 int      channel_still_open(struct ssh *);
 279 char    *channel_open_message(struct ssh *);
 280 int      channel_find_open(struct ssh *);
 281
 282 /* tcp forwarding */
 283 struct Forward;
 284 struct ForwardOptions;
 285 void     channel_set_af(struct ssh *, int af);
 286 void     channel_permit_all_opens(struct ssh *);
 287 void     channel_add_permitted_opens(struct ssh *, char *, int);
 288 int      channel_add_adm_permitted_opens(struct ssh *, char *, int);
 289 void     channel_copy_adm_permitted_opens(struct ssh *,
 290             const struct fwd_perm_list *);
 291 void     channel_disable_adm_local_opens(struct ssh *);
 292 void     channel_update_permitted_opens(struct ssh *, int, int);
 293 void     channel_clear_permitted_opens(struct ssh *);
 294 void     channel_clear_adm_permitted_opens(struct ssh *);
 295 void     channel_print_adm_permitted_opens(struct ssh *);
 296 Channel *channel_connect_to_port(struct ssh *, const char *, u_short,
 297             char *, char *, int *, const char **);
 298 Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *);
 299 Channel *channel_connect_stdio_fwd(struct ssh *, const char*,
 300             u_short, int, int);
 301 Channel *channel_connect_by_listen_address(struct ssh *, const char *,
 302             u_short, char *, char *);
 303 Channel *channel_connect_by_listen_path(struct ssh *, const char *,
 304             char *, char *);
 305 int      channel_request_remote_forwarding(struct ssh *, struct Forward *);
 306 int      channel_setup_local_fwd_listener(struct ssh *, struct Forward *,
 307             struct ForwardOptions *);
 308 int      channel_request_rforward_cancel(struct ssh *, struct Forward *);
 309 int      channel_setup_remote_fwd_listener(struct ssh *, struct Forward *,
 310             int *, struct ForwardOptions *);
 311 int      channel_cancel_rport_listener(struct ssh *, struct Forward *);
 312 int      channel_cancel_lport_listener(struct ssh *, struct Forward *,
 313             int, struct ForwardOptions *);
 314 int      permitopen_port(const char *);
 315
 316 /* x11 forwarding */
 317
 318 void     channel_set_x11_refuse_time(struct ssh *, u_int);
 319 int      x11_connect_display(struct ssh *);
 320 int      x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **);
 321 void     x11_request_forwarding_with_spoofing(struct ssh *, int,
 322             const char *, const char *, const char *, int);
 323
 324 /* channel close */
 325
 326 int      chan_is_dead(struct ssh *, Channel *, int);
 327 void     chan_mark_dead(struct ssh *, Channel *);
 328
 329 /* channel events */
 330
 331 void     chan_rcvd_oclose(struct ssh *, Channel *);
 332 void     chan_rcvd_eow(struct ssh *, Channel *);
 333 void     chan_read_failed(struct ssh *, Channel *);
 334 void     chan_ibuf_empty(struct ssh *, Channel *);
 335 void     chan_rcvd_ieof(struct ssh *, Channel *);
 336 void     chan_write_failed(struct ssh *, Channel *);
 337 void     chan_obuf_empty(struct ssh *, Channel *);
 338
 339 #endif