ttymodes.c

   1 /* $OpenBSD: ttymodes.c,v 1.25 2006/07/22 20:48:23 stevesk Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  *
   7  * As far as I am concerned, the code I have written for this software
   8  * can be used freely for any purpose.  Any derived versions of this
   9  * software must be clearly marked as such, and if the derived work is
  10  * incompatible with the protocol description in the RFC file, it must be
  11  * called by a name other than "ssh" or "Secure Shell".
  12  */
  13
  14 /*
  15  * SSH2 tty modes support by Kevin Steves.
  16  * Copyright (c) 2001 Kevin Steves.  All rights reserved.
  17  *
  18  * Redistribution and use in source and binary forms, with or without
  19  * modification, are permitted provided that the following conditions
  20  * are met:
  21  * 1. Redistributions of source code must retain the above copyright
  22  *    notice, this list of conditions and the following disclaimer.
  23  * 2. Redistributions in binary form must reproduce the above copyright
  24  *    notice, this list of conditions and the following disclaimer in the
  25  *    documentation and/or other materials provided with the distribution.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  28  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  29  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  30  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  31  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  32  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  33  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  34  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  35  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  36  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 /*
  40  * Encoding and decoding of terminal modes in a portable way.
  41  * Much of the format is defined in ttymodes.h; it is included multiple times
  42  * into this file with the appropriate macro definitions to generate the
  43  * suitable code.
  44  */
  45
  46 #include "includes.h"
  47
  48 #include <errno.h>
  49 #include <string.h>
  50 #include <termios.h>
  51
  52 #include "packet.h"
  53 #include "log.h"
  54 #include "ssh1.h"
  55 #include "compat.h"
  56 #include "buffer.h"
  57 #include "bufaux.h"
  58
  59 #define TTY_OP_END              0
  60 /*
  61  * uint32 (u_int) follows speed in SSH1 and SSH2
  62  */
  63 #define TTY_OP_ISPEED_PROTO1    192
  64 #define TTY_OP_OSPEED_PROTO1    193
  65 #define TTY_OP_ISPEED_PROTO2    128
  66 #define TTY_OP_OSPEED_PROTO2    129
  67
  68 /*
  69  * Converts POSIX speed_t to a baud rate.  The values of the
  70  * constants for speed_t are not themselves portable.
  71  */
  72 static int
  73 speed_to_baud(speed_t speed)
  74 {
  75         switch (speed) {
  76         case B0:
  77                 return 0;
  78         case B50:
  79                 return 50;
  80         case B75:
  81                 return 75;
  82         case B110:
  83                 return 110;
  84         case B134:
  85                 return 134;
  86         case B150:
  87                 return 150;
  88         case B200:
  89                 return 200;
  90         case B300:
  91                 return 300;
  92         case B600:
  93                 return 600;
  94         case B1200:
  95                 return 1200;
  96         case B1800:
  97                 return 1800;
  98         case B2400:
  99                 return 2400;
 100         case B4800:
 101                 return 4800;
 102         case B9600:
 103                 return 9600;
 104
 105 #ifdef B19200
 106         case B19200:
 107                 return 19200;
 108 #else /* B19200 */
 109 #ifdef EXTA
 110         case EXTA:
 111                 return 19200;
 112 #endif /* EXTA */
 113 #endif /* B19200 */
 114
 115 #ifdef B38400
 116         case B38400:
 117                 return 38400;
 118 #else /* B38400 */
 119 #ifdef EXTB
 120         case EXTB:
 121                 return 38400;
 122 #endif /* EXTB */
 123 #endif /* B38400 */
 124
 125 #ifdef B7200
 126         case B7200:
 127                 return 7200;
 128 #endif /* B7200 */
 129 #ifdef B14400
 130         case B14400:
 131                 return 14400;
 132 #endif /* B14400 */
 133 #ifdef B28800
 134         case B28800:
 135                 return 28800;
 136 #endif /* B28800 */
 137 #ifdef B57600
 138         case B57600:
 139                 return 57600;
 140 #endif /* B57600 */
 141 #ifdef B76800
 142         case B76800:
 143                 return 76800;
 144 #endif /* B76800 */
 145 #ifdef B115200
 146         case B115200:
 147                 return 115200;
 148 #endif /* B115200 */
 149 #ifdef B230400
 150         case B230400:
 151                 return 230400;
 152 #endif /* B230400 */
 153         default:
 154                 return 9600;
 155         }
 156 }
 157
 158 /*
 159  * Converts a numeric baud rate to a POSIX speed_t.
 160  */
 161 static speed_t
 162 baud_to_speed(int baud)
 163 {
 164         switch (baud) {
 165         case 0:
 166                 return B0;
 167         case 50:
 168                 return B50;
 169         case 75:
 170                 return B75;
 171         case 110:
 172                 return B110;
 173         case 134:
 174                 return B134;
 175         case 150:
 176                 return B150;
 177         case 200:
 178                 return B200;
 179         case 300:
 180                 return B300;
 181         case 600:
 182                 return B600;
 183         case 1200:
 184                 return B1200;
 185         case 1800:
 186                 return B1800;
 187         case 2400:
 188                 return B2400;
 189         case 4800:
 190                 return B4800;
 191         case 9600:
 192                 return B9600;
 193
 194 #ifdef B19200
 195         case 19200:
 196                 return B19200;
 197 #else /* B19200 */
 198 #ifdef EXTA
 199         case 19200:
 200                 return EXTA;
 201 #endif /* EXTA */
 202 #endif /* B19200 */
 203
 204 #ifdef B38400
 205         case 38400:
 206                 return B38400;
 207 #else /* B38400 */
 208 #ifdef EXTB
 209         case 38400:
 210                 return EXTB;
 211 #endif /* EXTB */
 212 #endif /* B38400 */
 213
 214 #ifdef B7200
 215         case 7200:
 216                 return B7200;
 217 #endif /* B7200 */
 218 #ifdef B14400
 219         case 14400:
 220                 return B14400;
 221 #endif /* B14400 */
 222 #ifdef B28800
 223         case 28800:
 224                 return B28800;
 225 #endif /* B28800 */
 226 #ifdef B57600
 227         case 57600:
 228                 return B57600;
 229 #endif /* B57600 */
 230 #ifdef B76800
 231         case 76800:
 232                 return B76800;
 233 #endif /* B76800 */
 234 #ifdef B115200
 235         case 115200:
 236                 return B115200;
 237 #endif /* B115200 */
 238 #ifdef B230400
 239         case 230400:
 240                 return B230400;
 241 #endif /* B230400 */
 242         default:
 243                 return B9600;
 244         }
 245 }
 246
 247 /*
 248  * Encode a special character into SSH line format.
 249  */
 250 static u_int
 251 special_char_encode(cc_t c)
 252 {
 253 #ifdef _POSIX_VDISABLE
 254         if (c == _POSIX_VDISABLE)
 255                 return 255;
 256 #endif /* _POSIX_VDISABLE */
 257         return c;
 258 }
 259
 260 /*
 261  * Decode a special character from SSH line format.
 262  */
 263 static cc_t
 264 special_char_decode(u_int c)
 265 {
 266 #ifdef _POSIX_VDISABLE
 267         if (c == 255)
 268                 return _POSIX_VDISABLE;
 269 #endif /* _POSIX_VDISABLE */
 270         return c;
 271 }
 272
 273 /*
 274  * Encodes terminal modes for the terminal referenced by fd
 275  * or tiop in a portable manner, and appends the modes to a packet
 276  * being constructed.
 277  */
 278 void
 279 tty_make_modes(int fd, struct termios *tiop)
 280 {
 281         struct termios tio;
 282         int baud;
 283         Buffer buf;
 284         int tty_op_ospeed, tty_op_ispeed;
 285         void (*put_arg)(Buffer *, u_int);
 286
 287         buffer_init(&buf);
 288         if (compat20) {
 289                 tty_op_ospeed = TTY_OP_OSPEED_PROTO2;
 290                 tty_op_ispeed = TTY_OP_ISPEED_PROTO2;
 291                 put_arg = buffer_put_int;
 292         } else {
 293                 tty_op_ospeed = TTY_OP_OSPEED_PROTO1;
 294                 tty_op_ispeed = TTY_OP_ISPEED_PROTO1;
 295                 put_arg = (void (*)(Buffer *, u_int)) buffer_put_char;
 296         }
 297
 298         if (tiop == NULL) {
 299                 if (tcgetattr(fd, &tio) == -1) {
 300                         logit("tcgetattr: %.100s", strerror(errno));
 301                         goto end;
 302                 }
 303         } else
 304                 tio = *tiop;
 305
 306         /* Store input and output baud rates. */
 307         baud = speed_to_baud(cfgetospeed(&tio));
 308         debug3("tty_make_modes: ospeed %d", baud);
 309         buffer_put_char(&buf, tty_op_ospeed);
 310         buffer_put_int(&buf, baud);
 311         baud = speed_to_baud(cfgetispeed(&tio));
 312         debug3("tty_make_modes: ispeed %d", baud);
 313         buffer_put_char(&buf, tty_op_ispeed);
 314         buffer_put_int(&buf, baud);
 315
 316         /* Store values of mode flags. */
 317 #define TTYCHAR(NAME, OP) \
 318         debug3("tty_make_modes: %d %d", OP, tio.c_cc[NAME]); \
 319         buffer_put_char(&buf, OP); \
 320         put_arg(&buf, special_char_encode(tio.c_cc[NAME]));
 321
 322 #define TTYMODE(NAME, FIELD, OP) \
 323         debug3("tty_make_modes: %d %d", OP, ((tio.FIELD & NAME) != 0)); \
 324         buffer_put_char(&buf, OP); \
 325         put_arg(&buf, ((tio.FIELD & NAME) != 0));
 326
 327 #include "ttymodes.h"
 328
 329 #undef TTYCHAR
 330 #undef TTYMODE
 331
 332 end:
 333         /* Mark end of mode data. */
 334         buffer_put_char(&buf, TTY_OP_END);
 335         if (compat20)
 336                 packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
 337         else
 338                 packet_put_raw(buffer_ptr(&buf), buffer_len(&buf));
 339         buffer_free(&buf);
 340 }
 341
 342 /*
 343  * Decodes terminal modes for the terminal referenced by fd in a portable
 344  * manner from a packet being read.
 345  */
 346 void
 347 tty_parse_modes(int fd, int *n_bytes_ptr)
 348 {
 349         struct termios tio;
 350         int opcode, baud;
 351         int n_bytes = 0;
 352         int failure = 0;
 353         u_int (*get_arg)(void);
 354         int arg, arg_size;
 355
 356         if (compat20) {
 357                 *n_bytes_ptr = packet_get_int();
 358                 debug3("tty_parse_modes: SSH2 n_bytes %d", *n_bytes_ptr);
 359                 if (*n_bytes_ptr == 0)
 360                         return;
 361                 get_arg = packet_get_int;
 362                 arg_size = 4;
 363         } else {
 364                 get_arg = packet_get_char;
 365                 arg_size = 1;
 366         }
 367
 368         /*
 369          * Get old attributes for the terminal.  We will modify these
 370          * flags. I am hoping that if there are any machine-specific
 371          * modes, they will initially have reasonable values.
 372          */
 373         if (tcgetattr(fd, &tio) == -1) {
 374                 logit("tcgetattr: %.100s", strerror(errno));
 375                 failure = -1;
 376         }
 377
 378         for (;;) {
 379                 n_bytes += 1;
 380                 opcode = packet_get_char();
 381                 switch (opcode) {
 382                 case TTY_OP_END:
 383                         goto set;
 384
 385                 /* XXX: future conflict possible */
 386                 case TTY_OP_ISPEED_PROTO1:
 387                 case TTY_OP_ISPEED_PROTO2:
 388                         n_bytes += 4;
 389                         baud = packet_get_int();
 390                         debug3("tty_parse_modes: ispeed %d", baud);
 391                         if (failure != -1 &&
 392                             cfsetispeed(&tio, baud_to_speed(baud)) == -1)
 393                                 error("cfsetispeed failed for %d", baud);
 394                         break;
 395
 396                 /* XXX: future conflict possible */
 397                 case TTY_OP_OSPEED_PROTO1:
 398                 case TTY_OP_OSPEED_PROTO2:
 399                         n_bytes += 4;
 400                         baud = packet_get_int();
 401                         debug3("tty_parse_modes: ospeed %d", baud);
 402                         if (failure != -1 &&
 403                             cfsetospeed(&tio, baud_to_speed(baud)) == -1)
 404                                 error("cfsetospeed failed for %d", baud);
 405                         break;
 406
 407 #define TTYCHAR(NAME, OP) \
 408         case OP: \
 409           n_bytes += arg_size; \
 410           tio.c_cc[NAME] = special_char_decode(get_arg()); \
 411           debug3("tty_parse_modes: %d %d", OP, tio.c_cc[NAME]); \
 412           break;
 413 #define TTYMODE(NAME, FIELD, OP) \
 414         case OP: \
 415           n_bytes += arg_size; \
 416           if ((arg = get_arg())) \
 417             tio.FIELD |= NAME; \
 418           else \
 419             tio.FIELD &= ~NAME; \
 420           debug3("tty_parse_modes: %d %d", OP, arg); \
 421           break;
 422
 423 #include "ttymodes.h"
 424
 425 #undef TTYCHAR
 426 #undef TTYMODE
 427
 428                 default:
 429                         debug("Ignoring unsupported tty mode opcode %d (0x%x)",
 430                             opcode, opcode);
 431                         if (!compat20) {
 432                                 /*
 433                                  * SSH1:
 434                                  * Opcodes 1 to 127 are defined to have
 435                                  * a one-byte argument.
 436                                  * Opcodes 128 to 159 are defined to have
 437                                  * an integer argument.
 438                                  */
 439                                 if (opcode > 0 && opcode < 128) {
 440                                         n_bytes += 1;
 441                                         (void) packet_get_char();
 442                                         break;
 443                                 } else if (opcode >= 128 && opcode < 160) {
 444                                         n_bytes += 4;
 445                                         (void) packet_get_int();
 446                                         break;
 447                                 } else {
 448                                         /*
 449                                          * It is a truly undefined opcode (160 to 255).
 450                                          * We have no idea about its arguments.  So we
 451                                          * must stop parsing.  Note that some data
 452                                          * may be left in the packet; hopefully there
 453                                          * is nothing more coming after the mode data.
 454                                          */
 455                                         logit("parse_tty_modes: unknown opcode %d",
 456                                             opcode);
 457                                         goto set;
 458                                 }
 459                         } else {
 460                                 /*
 461                                  * SSH2:
 462                                  * Opcodes 1 to 159 are defined to have
 463                                  * a uint32 argument.
 464                                  * Opcodes 160 to 255 are undefined and
 465                                  * cause parsing to stop.
 466                                  */
 467                                 if (opcode > 0 && opcode < 160) {
 468                                         n_bytes += 4;
 469                                         (void) packet_get_int();
 470                                         break;
 471                                 } else {
 472                                         logit("parse_tty_modes: unknown opcode %d",
 473                                             opcode);
 474                                         goto set;
 475                                 }
 476                         }
 477                 }
 478         }
 479
 480 set:
 481         if (*n_bytes_ptr != n_bytes) {
 482                 *n_bytes_ptr = n_bytes;
 483                 logit("parse_tty_modes: n_bytes_ptr != n_bytes: %d %d",
 484                     *n_bytes_ptr, n_bytes);
 485                 return;         /* Don't process bytes passed */
 486         }
 487         if (failure == -1)
 488                 return;         /* Packet parsed ok but tcgetattr() failed */
 489
 490         /* Set the new modes for the terminal. */
 491         if (tcsetattr(fd, TCSANOW, &tio) == -1)
 492                 logit("Setting tty modes failed: %.100s", strerror(errno));
 493 }