crypto/openssh/ttymodes.c

   1 /* $OpenBSD: ttymodes.c,v 1.30 2016/05/04 14:22:33 markus 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 <sys/types.h>
  49
  50 #include <errno.h>
  51 #include <string.h>
  52 #include <termios.h>
  53 #include <stdarg.h>
  54
  55 #include "packet.h"
  56 #include "log.h"
  57 #include "compat.h"
  58 #include "buffer.h"
  59
  60 #define TTY_OP_END              0
  61 /*
  62  * uint32 (u_int) follows speed in SSH1 and SSH2
  63  */
  64 #define TTY_OP_ISPEED_PROTO1    192
  65 #define TTY_OP_OSPEED_PROTO1    193
  66 #define TTY_OP_ISPEED_PROTO2    128
  67 #define TTY_OP_OSPEED_PROTO2    129
  68
  69 /*
  70  * Converts POSIX speed_t to a baud rate.  The values of the
  71  * constants for speed_t are not themselves portable.
  72  */
  73 static int
  74 speed_to_baud(speed_t speed)
  75 {
  76         switch (speed) {
  77         case B0:
  78                 return 0;
  79         case B50:
  80                 return 50;
  81         case B75:
  82                 return 75;
  83         case B110:
  84                 return 110;
  85         case B134:
  86                 return 134;
  87         case B150:
  88                 return 150;
  89         case B200:
  90                 return 200;
  91         case B300:
  92                 return 300;
  93         case B600:
  94                 return 600;
  95         case B1200:
  96                 return 1200;
  97         case B1800:
  98                 return 1800;
  99         case B2400:
 100                 return 2400;
 101         case B4800:
 102                 return 4800;
 103         case B9600:
 104                 return 9600;
 105
 106 #ifdef B19200
 107         case B19200:
 108                 return 19200;
 109 #else /* B19200 */
 110 #ifdef EXTA
 111         case EXTA:
 112                 return 19200;
 113 #endif /* EXTA */
 114 #endif /* B19200 */
 115
 116 #ifdef B38400
 117         case B38400:
 118                 return 38400;
 119 #else /* B38400 */
 120 #ifdef EXTB
 121         case EXTB:
 122                 return 38400;
 123 #endif /* EXTB */
 124 #endif /* B38400 */
 125
 126 #ifdef B7200
 127         case B7200:
 128                 return 7200;
 129 #endif /* B7200 */
 130 #ifdef B14400
 131         case B14400:
 132                 return 14400;
 133 #endif /* B14400 */
 134 #ifdef B28800
 135         case B28800:
 136                 return 28800;
 137 #endif /* B28800 */
 138 #ifdef B57600
 139         case B57600:
 140                 return 57600;
 141 #endif /* B57600 */
 142 #ifdef B76800
 143         case B76800:
 144                 return 76800;
 145 #endif /* B76800 */
 146 #ifdef B115200
 147         case B115200:
 148                 return 115200;
 149 #endif /* B115200 */
 150 #ifdef B230400
 151         case B230400:
 152                 return 230400;
 153 #endif /* B230400 */
 154         default:
 155                 return 9600;
 156         }
 157 }
 158
 159 /*
 160  * Converts a numeric baud rate to a POSIX speed_t.
 161  */
 162 static speed_t
 163 baud_to_speed(int baud)
 164 {
 165         switch (baud) {
 166         case 0:
 167                 return B0;
 168         case 50:
 169                 return B50;
 170         case 75:
 171                 return B75;
 172         case 110:
 173                 return B110;
 174         case 134:
 175                 return B134;
 176         case 150:
 177                 return B150;
 178         case 200:
 179                 return B200;
 180         case 300:
 181                 return B300;
 182         case 600:
 183                 return B600;
 184         case 1200:
 185                 return B1200;
 186         case 1800:
 187                 return B1800;
 188         case 2400:
 189                 return B2400;
 190         case 4800:
 191                 return B4800;
 192         case 9600:
 193                 return B9600;
 194
 195 #ifdef B19200
 196         case 19200:
 197                 return B19200;
 198 #else /* B19200 */
 199 #ifdef EXTA
 200         case 19200:
 201                 return EXTA;
 202 #endif /* EXTA */
 203 #endif /* B19200 */
 204
 205 #ifdef B38400
 206         case 38400:
 207                 return B38400;
 208 #else /* B38400 */
 209 #ifdef EXTB
 210         case 38400:
 211                 return EXTB;
 212 #endif /* EXTB */
 213 #endif /* B38400 */
 214
 215 #ifdef B7200
 216         case 7200:
 217                 return B7200;
 218 #endif /* B7200 */
 219 #ifdef B14400
 220         case 14400:
 221                 return B14400;
 222 #endif /* B14400 */
 223 #ifdef B28800
 224         case 28800:
 225                 return B28800;
 226 #endif /* B28800 */
 227 #ifdef B57600
 228         case 57600:
 229                 return B57600;
 230 #endif /* B57600 */
 231 #ifdef B76800
 232         case 76800:
 233                 return B76800;
 234 #endif /* B76800 */
 235 #ifdef B115200
 236         case 115200:
 237                 return B115200;
 238 #endif /* B115200 */
 239 #ifdef B230400
 240         case 230400:
 241                 return B230400;
 242 #endif /* B230400 */
 243         default:
 244                 return B9600;
 245         }
 246 }
 247
 248 /*
 249  * Encode a special character into SSH line format.
 250  */
 251 static u_int
 252 special_char_encode(cc_t c)
 253 {
 254 #ifdef _POSIX_VDISABLE
 255         if (c == _POSIX_VDISABLE)
 256                 return 255;
 257 #endif /* _POSIX_VDISABLE */
 258         return c;
 259 }
 260
 261 /*
 262  * Decode a special character from SSH line format.
 263  */
 264 static cc_t
 265 special_char_decode(u_int c)
 266 {
 267 #ifdef _POSIX_VDISABLE
 268         if (c == 255)
 269                 return _POSIX_VDISABLE;
 270 #endif /* _POSIX_VDISABLE */
 271         return c;
 272 }
 273
 274 /*
 275  * Encodes terminal modes for the terminal referenced by fd
 276  * or tiop in a portable manner, and appends the modes to a packet
 277  * being constructed.
 278  */
 279 void
 280 tty_make_modes(int fd, struct termios *tiop)
 281 {
 282         struct termios tio;
 283         int baud;
 284         Buffer buf;
 285         int tty_op_ospeed, tty_op_ispeed;
 286         void (*put_arg)(Buffer *, u_int);
 287
 288         buffer_init(&buf);
 289         if (compat20) {
 290                 tty_op_ospeed = TTY_OP_OSPEED_PROTO2;
 291                 tty_op_ispeed = TTY_OP_ISPEED_PROTO2;
 292                 put_arg = buffer_put_int;
 293         } else {
 294                 tty_op_ospeed = TTY_OP_OSPEED_PROTO1;
 295                 tty_op_ispeed = TTY_OP_ISPEED_PROTO1;
 296                 put_arg = (void (*)(Buffer *, u_int)) buffer_put_char;
 297         }
 298
 299         if (tiop == NULL) {
 300                 if (fd == -1) {
 301                         debug("tty_make_modes: no fd or tio");
 302                         goto end;
 303                 }
 304                 if (tcgetattr(fd, &tio) == -1) {
 305                         logit("tcgetattr: %.100s", strerror(errno));
 306                         goto end;
 307                 }
 308         } else
 309                 tio = *tiop;
 310
 311         /* Store input and output baud rates. */
 312         baud = speed_to_baud(cfgetospeed(&tio));
 313         buffer_put_char(&buf, tty_op_ospeed);
 314         buffer_put_int(&buf, baud);
 315         baud = speed_to_baud(cfgetispeed(&tio));
 316         buffer_put_char(&buf, tty_op_ispeed);
 317         buffer_put_int(&buf, baud);
 318
 319         /* Store values of mode flags. */
 320 #define TTYCHAR(NAME, OP) \
 321         buffer_put_char(&buf, OP); \
 322         put_arg(&buf, special_char_encode(tio.c_cc[NAME]));
 323
 324 #define TTYMODE(NAME, FIELD, OP) \
 325         buffer_put_char(&buf, OP); \
 326         put_arg(&buf, ((tio.FIELD & NAME) != 0));
 327
 328 #include "ttymodes.h"
 329
 330 #undef TTYCHAR
 331 #undef TTYMODE
 332
 333 end:
 334         /* Mark end of mode data. */
 335         buffer_put_char(&buf, TTY_OP_END);
 336         if (compat20)
 337                 packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
 338         else
 339                 packet_put_raw(buffer_ptr(&buf), buffer_len(&buf));
 340         buffer_free(&buf);
 341 }
 342
 343 /*
 344  * Decodes terminal modes for the terminal referenced by fd in a portable
 345  * manner from a packet being read.
 346  */
 347 void
 348 tty_parse_modes(int fd, int *n_bytes_ptr)
 349 {
 350         struct termios tio;
 351         int opcode, baud;
 352         int n_bytes = 0;
 353         int failure = 0;
 354         u_int (*get_arg)(void);
 355         int arg_size;
 356
 357         if (compat20) {
 358                 *n_bytes_ptr = packet_get_int();
 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                         if (failure != -1 &&
 391                             cfsetispeed(&tio, baud_to_speed(baud)) == -1)
 392                                 error("cfsetispeed failed for %d", baud);
 393                         break;
 394
 395                 /* XXX: future conflict possible */
 396                 case TTY_OP_OSPEED_PROTO1:
 397                 case TTY_OP_OSPEED_PROTO2:
 398                         n_bytes += 4;
 399                         baud = packet_get_int();
 400                         if (failure != -1 &&
 401                             cfsetospeed(&tio, baud_to_speed(baud)) == -1)
 402                                 error("cfsetospeed failed for %d", baud);
 403                         break;
 404
 405 #define TTYCHAR(NAME, OP) \
 406         case OP: \
 407           n_bytes += arg_size; \
 408           tio.c_cc[NAME] = special_char_decode(get_arg()); \
 409           break;
 410 #define TTYMODE(NAME, FIELD, OP) \
 411         case OP: \
 412           n_bytes += arg_size; \
 413           if (get_arg()) \
 414             tio.FIELD |= NAME; \
 415           else \
 416             tio.FIELD &= ~NAME; \
 417           break;
 418
 419 #include "ttymodes.h"
 420
 421 #undef TTYCHAR
 422 #undef TTYMODE
 423
 424                 default:
 425                         debug("Ignoring unsupported tty mode opcode %d (0x%x)",
 426                             opcode, opcode);
 427                         if (!compat20) {
 428                                 /*
 429                                  * SSH1:
 430                                  * Opcodes 1 to 127 are defined to have
 431                                  * a one-byte argument.
 432                                  * Opcodes 128 to 159 are defined to have
 433                                  * an integer argument.
 434                                  */
 435                                 if (opcode > 0 && opcode < 128) {
 436                                         n_bytes += 1;
 437                                         (void) packet_get_char();
 438                                         break;
 439                                 } else if (opcode >= 128 && opcode < 160) {
 440                                         n_bytes += 4;
 441                                         (void) packet_get_int();
 442                                         break;
 443                                 } else {
 444                                         /*
 445                                          * It is a truly undefined opcode (160 to 255).
 446                                          * We have no idea about its arguments.  So we
 447                                          * must stop parsing.  Note that some data
 448                                          * may be left in the packet; hopefully there
 449                                          * is nothing more coming after the mode data.
 450                                          */
 451                                         logit("parse_tty_modes: unknown opcode %d",
 452                                             opcode);
 453                                         goto set;
 454                                 }
 455                         } else {
 456                                 /*
 457                                  * SSH2:
 458                                  * Opcodes 1 to 159 are defined to have
 459                                  * a uint32 argument.
 460                                  * Opcodes 160 to 255 are undefined and
 461                                  * cause parsing to stop.
 462                                  */
 463                                 if (opcode > 0 && opcode < 160) {
 464                                         n_bytes += 4;
 465                                         (void) packet_get_int();
 466                                         break;
 467                                 } else {
 468                                         logit("parse_tty_modes: unknown opcode %d",
 469                                             opcode);
 470                                         goto set;
 471                                 }
 472                         }
 473                 }
 474         }
 475
 476 set:
 477         if (*n_bytes_ptr != n_bytes) {
 478                 *n_bytes_ptr = n_bytes;
 479                 logit("parse_tty_modes: n_bytes_ptr != n_bytes: %d %d",
 480                     *n_bytes_ptr, n_bytes);
 481                 return;         /* Don't process bytes passed */
 482         }
 483         if (failure == -1)
 484                 return;         /* Packet parsed ok but tcgetattr() failed */
 485
 486         /* Set the new modes for the terminal. */
 487         if (tcsetattr(fd, TCSANOW, &tio) == -1)
 488                 logit("Setting tty modes failed: %.100s", strerror(errno));
 489 }