crypto/openssh/ttymodes.c

   1 /* $OpenBSD: ttymodes.c,v 1.32 2017/04/30 23:26:54 djm 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.
  63  */
  64 #define TTY_OP_ISPEED   128
  65 #define TTY_OP_OSPEED   129
  66
  67 /*
  68  * Converts POSIX speed_t to a baud rate.  The values of the
  69  * constants for speed_t are not themselves portable.
  70  */
  71 static int
  72 speed_to_baud(speed_t speed)
  73 {
  74         switch (speed) {
  75         case B0:
  76                 return 0;
  77         case B50:
  78                 return 50;
  79         case B75:
  80                 return 75;
  81         case B110:
  82                 return 110;
  83         case B134:
  84                 return 134;
  85         case B150:
  86                 return 150;
  87         case B200:
  88                 return 200;
  89         case B300:
  90                 return 300;
  91         case B600:
  92                 return 600;
  93         case B1200:
  94                 return 1200;
  95         case B1800:
  96                 return 1800;
  97         case B2400:
  98                 return 2400;
  99         case B4800:
 100                 return 4800;
 101         case B9600:
 102                 return 9600;
 103
 104 #ifdef B19200
 105         case B19200:
 106                 return 19200;
 107 #else /* B19200 */
 108 #ifdef EXTA
 109         case EXTA:
 110                 return 19200;
 111 #endif /* EXTA */
 112 #endif /* B19200 */
 113
 114 #ifdef B38400
 115         case B38400:
 116                 return 38400;
 117 #else /* B38400 */
 118 #ifdef EXTB
 119         case EXTB:
 120                 return 38400;
 121 #endif /* EXTB */
 122 #endif /* B38400 */
 123
 124 #ifdef B7200
 125         case B7200:
 126                 return 7200;
 127 #endif /* B7200 */
 128 #ifdef B14400
 129         case B14400:
 130                 return 14400;
 131 #endif /* B14400 */
 132 #ifdef B28800
 133         case B28800:
 134                 return 28800;
 135 #endif /* B28800 */
 136 #ifdef B57600
 137         case B57600:
 138                 return 57600;
 139 #endif /* B57600 */
 140 #ifdef B76800
 141         case B76800:
 142                 return 76800;
 143 #endif /* B76800 */
 144 #ifdef B115200
 145         case B115200:
 146                 return 115200;
 147 #endif /* B115200 */
 148 #ifdef B230400
 149         case B230400:
 150                 return 230400;
 151 #endif /* B230400 */
 152         default:
 153                 return 9600;
 154         }
 155 }
 156
 157 /*
 158  * Converts a numeric baud rate to a POSIX speed_t.
 159  */
 160 static speed_t
 161 baud_to_speed(int baud)
 162 {
 163         switch (baud) {
 164         case 0:
 165                 return B0;
 166         case 50:
 167                 return B50;
 168         case 75:
 169                 return B75;
 170         case 110:
 171                 return B110;
 172         case 134:
 173                 return B134;
 174         case 150:
 175                 return B150;
 176         case 200:
 177                 return B200;
 178         case 300:
 179                 return B300;
 180         case 600:
 181                 return B600;
 182         case 1200:
 183                 return B1200;
 184         case 1800:
 185                 return B1800;
 186         case 2400:
 187                 return B2400;
 188         case 4800:
 189                 return B4800;
 190         case 9600:
 191                 return B9600;
 192
 193 #ifdef B19200
 194         case 19200:
 195                 return B19200;
 196 #else /* B19200 */
 197 #ifdef EXTA
 198         case 19200:
 199                 return EXTA;
 200 #endif /* EXTA */
 201 #endif /* B19200 */
 202
 203 #ifdef B38400
 204         case 38400:
 205                 return B38400;
 206 #else /* B38400 */
 207 #ifdef EXTB
 208         case 38400:
 209                 return EXTB;
 210 #endif /* EXTB */
 211 #endif /* B38400 */
 212
 213 #ifdef B7200
 214         case 7200:
 215                 return B7200;
 216 #endif /* B7200 */
 217 #ifdef B14400
 218         case 14400:
 219                 return B14400;
 220 #endif /* B14400 */
 221 #ifdef B28800
 222         case 28800:
 223                 return B28800;
 224 #endif /* B28800 */
 225 #ifdef B57600
 226         case 57600:
 227                 return B57600;
 228 #endif /* B57600 */
 229 #ifdef B76800
 230         case 76800:
 231                 return B76800;
 232 #endif /* B76800 */
 233 #ifdef B115200
 234         case 115200:
 235                 return B115200;
 236 #endif /* B115200 */
 237 #ifdef B230400
 238         case 230400:
 239                 return B230400;
 240 #endif /* B230400 */
 241         default:
 242                 return B9600;
 243         }
 244 }
 245
 246 /*
 247  * Encode a special character into SSH line format.
 248  */
 249 static u_int
 250 special_char_encode(cc_t c)
 251 {
 252 #ifdef _POSIX_VDISABLE
 253         if (c == _POSIX_VDISABLE)
 254                 return 255;
 255 #endif /* _POSIX_VDISABLE */
 256         return c;
 257 }
 258
 259 /*
 260  * Decode a special character from SSH line format.
 261  */
 262 static cc_t
 263 special_char_decode(u_int c)
 264 {
 265 #ifdef _POSIX_VDISABLE
 266         if (c == 255)
 267                 return _POSIX_VDISABLE;
 268 #endif /* _POSIX_VDISABLE */
 269         return c;
 270 }
 271
 272 /*
 273  * Encodes terminal modes for the terminal referenced by fd
 274  * or tiop in a portable manner, and appends the modes to a packet
 275  * being constructed.
 276  */
 277 void
 278 tty_make_modes(int fd, struct termios *tiop)
 279 {
 280         struct termios tio;
 281         int baud;
 282         Buffer buf;
 283
 284         buffer_init(&buf);
 285
 286         if (tiop == NULL) {
 287                 if (fd == -1) {
 288                         debug("tty_make_modes: no fd or tio");
 289                         goto end;
 290                 }
 291                 if (tcgetattr(fd, &tio) == -1) {
 292                         logit("tcgetattr: %.100s", strerror(errno));
 293                         goto end;
 294                 }
 295         } else
 296                 tio = *tiop;
 297
 298         /* Store input and output baud rates. */
 299         baud = speed_to_baud(cfgetospeed(&tio));
 300         buffer_put_char(&buf, TTY_OP_OSPEED);
 301         buffer_put_int(&buf, baud);
 302         baud = speed_to_baud(cfgetispeed(&tio));
 303         buffer_put_char(&buf, TTY_OP_ISPEED);
 304         buffer_put_int(&buf, baud);
 305
 306         /* Store values of mode flags. */
 307 #define TTYCHAR(NAME, OP) \
 308         buffer_put_char(&buf, OP); \
 309         buffer_put_int(&buf, special_char_encode(tio.c_cc[NAME]));
 310
 311 #define TTYMODE(NAME, FIELD, OP) \
 312         buffer_put_char(&buf, OP); \
 313         buffer_put_int(&buf, ((tio.FIELD & NAME) != 0));
 314
 315 #include "ttymodes.h"
 316
 317 #undef TTYCHAR
 318 #undef TTYMODE
 319
 320 end:
 321         /* Mark end of mode data. */
 322         buffer_put_char(&buf, TTY_OP_END);
 323         packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
 324         buffer_free(&buf);
 325 }
 326
 327 /*
 328  * Decodes terminal modes for the terminal referenced by fd in a portable
 329  * manner from a packet being read.
 330  */
 331 void
 332 tty_parse_modes(int fd, int *n_bytes_ptr)
 333 {
 334         struct termios tio;
 335         int opcode, baud;
 336         int n_bytes = 0;
 337         int failure = 0;
 338
 339         *n_bytes_ptr = packet_get_int();
 340         if (*n_bytes_ptr == 0)
 341                 return;
 342
 343         /*
 344          * Get old attributes for the terminal.  We will modify these
 345          * flags. I am hoping that if there are any machine-specific
 346          * modes, they will initially have reasonable values.
 347          */
 348         if (tcgetattr(fd, &tio) == -1) {
 349                 logit("tcgetattr: %.100s", strerror(errno));
 350                 failure = -1;
 351         }
 352
 353         for (;;) {
 354                 n_bytes += 1;
 355                 opcode = packet_get_char();
 356                 switch (opcode) {
 357                 case TTY_OP_END:
 358                         goto set;
 359
 360                 case TTY_OP_ISPEED:
 361                         n_bytes += 4;
 362                         baud = packet_get_int();
 363                         if (failure != -1 &&
 364                             cfsetispeed(&tio, baud_to_speed(baud)) == -1)
 365                                 error("cfsetispeed failed for %d", baud);
 366                         break;
 367
 368                 case TTY_OP_OSPEED:
 369                         n_bytes += 4;
 370                         baud = packet_get_int();
 371                         if (failure != -1 &&
 372                             cfsetospeed(&tio, baud_to_speed(baud)) == -1)
 373                                 error("cfsetospeed failed for %d", baud);
 374                         break;
 375
 376 #define TTYCHAR(NAME, OP) \
 377         case OP: \
 378           n_bytes += 4; \
 379           tio.c_cc[NAME] = special_char_decode(packet_get_int()); \
 380           break;
 381 #define TTYMODE(NAME, FIELD, OP) \
 382         case OP: \
 383           n_bytes += 4; \
 384           if (packet_get_int()) \
 385             tio.FIELD |= NAME; \
 386           else \
 387             tio.FIELD &= ~NAME; \
 388           break;
 389
 390 #include "ttymodes.h"
 391
 392 #undef TTYCHAR
 393 #undef TTYMODE
 394
 395                 default:
 396                         debug("Ignoring unsupported tty mode opcode %d (0x%x)",
 397                             opcode, opcode);
 398                         /*
 399                          * SSH2:
 400                          * Opcodes 1 to 159 are defined to have a uint32
 401                          * argument.
 402                          * Opcodes 160 to 255 are undefined and cause parsing
 403                          * to stop.
 404                          */
 405                         if (opcode > 0 && opcode < 160) {
 406                                 n_bytes += 4;
 407                                 (void) packet_get_int();
 408                                 break;
 409                         } else {
 410                                 logit("parse_tty_modes: unknown opcode %d",
 411                                     opcode);
 412                                 goto set;
 413                         }
 414                 }
 415         }
 416
 417 set:
 418         if (*n_bytes_ptr != n_bytes) {
 419                 *n_bytes_ptr = n_bytes;
 420                 logit("parse_tty_modes: n_bytes_ptr != n_bytes: %d %d",
 421                     *n_bytes_ptr, n_bytes);
 422                 return;         /* Don't process bytes passed */
 423         }
 424         if (failure == -1)
 425                 return;         /* Packet parsed ok but tcgetattr() failed */
 426
 427         /* Set the new modes for the terminal. */
 428         if (tcsetattr(fd, TCSANOW, &tio) == -1)
 429                 logit("Setting tty modes failed: %.100s", strerror(errno));
 430 }