1 /* $OpenBSD: ttymodes.c,v 1.36 2021/01/27 09:26:54 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 "sshbuf.h" 59 #include "ssherr.h" 60 61 #define TTY_OP_END 0 62 /* 63 * uint32 (u_int) follows speed. 64 */ 65 #define TTY_OP_ISPEED 128 66 #define TTY_OP_OSPEED 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 ssh_tty_make_modes(struct ssh *ssh, int fd, struct termios *tiop) 280 { 281 struct termios tio; 282 struct sshbuf *buf; 283 int r, ibaud, obaud; 284 285 if ((buf = sshbuf_new()) == NULL) 286 fatal_f("sshbuf_new failed"); 287 288 if (tiop == NULL) { 289 if (fd == -1) { 290 debug_f("no fd or tio"); 291 goto end; 292 } 293 if (tcgetattr(fd, &tio) == -1) { 294 logit("tcgetattr: %.100s", strerror(errno)); 295 goto end; 296 } 297 } else 298 tio = *tiop; 299 300 /* Store input and output baud rates. */ 301 obaud = speed_to_baud(cfgetospeed(&tio)); 302 ibaud = speed_to_baud(cfgetispeed(&tio)); 303 if ((r = sshbuf_put_u8(buf, TTY_OP_OSPEED)) != 0 || 304 (r = sshbuf_put_u32(buf, obaud)) != 0 || 305 (r = sshbuf_put_u8(buf, TTY_OP_ISPEED)) != 0 || 306 (r = sshbuf_put_u32(buf, ibaud)) != 0) 307 fatal_fr(r, "compose"); 308 309 /* Store values of mode flags. */ 310 #define TTYCHAR(NAME, OP) \ 311 if ((r = sshbuf_put_u8(buf, OP)) != 0 || \ 312 (r = sshbuf_put_u32(buf, \ 313 special_char_encode(tio.c_cc[NAME]))) != 0) \ 314 fatal_fr(r, "compose %s", #NAME); 315 316 #define SSH_TTYMODE_IUTF8 42 /* for SSH_BUG_UTF8TTYMODE */ 317 318 #define TTYMODE(NAME, FIELD, OP) \ 319 if (OP == SSH_TTYMODE_IUTF8 && (ssh->compat & SSH_BUG_UTF8TTYMODE)) { \ 320 debug3_f("SSH_BUG_UTF8TTYMODE"); \ 321 } else if ((r = sshbuf_put_u8(buf, OP)) != 0 || \ 322 (r = sshbuf_put_u32(buf, ((tio.FIELD & NAME) != 0))) != 0) \ 323 fatal_fr(r, "compose %s", #NAME); 324 325 #include "ttymodes.h" 326 327 #undef TTYCHAR 328 #undef TTYMODE 329 330 end: 331 /* Mark end of mode data. */ 332 if ((r = sshbuf_put_u8(buf, TTY_OP_END)) != 0 || 333 (r = sshpkt_put_stringb(ssh, buf)) != 0) 334 fatal_fr(r, "compose end"); 335 sshbuf_free(buf); 336 } 337 338 /* 339 * Decodes terminal modes for the terminal referenced by fd in a portable 340 * manner from a packet being read. 341 */ 342 void 343 ssh_tty_parse_modes(struct ssh *ssh, int fd) 344 { 345 struct termios tio; 346 struct sshbuf *buf; 347 const u_char *data; 348 u_char opcode; 349 u_int baud, u; 350 int r, failure = 0; 351 size_t len; 352 353 if ((r = sshpkt_get_string_direct(ssh, &data, &len)) != 0) 354 fatal_fr(r, "parse"); 355 if (len == 0) 356 return; 357 if ((buf = sshbuf_from(data, len)) == NULL) { 358 error_f("sshbuf_from failed"); 359 return; 360 } 361 362 /* 363 * Get old attributes for the terminal. We will modify these 364 * flags. I am hoping that if there are any machine-specific 365 * modes, they will initially have reasonable values. 366 */ 367 if (tcgetattr(fd, &tio) == -1) { 368 logit("tcgetattr: %.100s", strerror(errno)); 369 failure = -1; 370 } 371 372 while (sshbuf_len(buf) > 0) { 373 if ((r = sshbuf_get_u8(buf, &opcode)) != 0) 374 fatal_fr(r, "parse opcode"); 375 switch (opcode) { 376 case TTY_OP_END: 377 goto set; 378 379 case TTY_OP_ISPEED: 380 if ((r = sshbuf_get_u32(buf, &baud)) != 0) 381 fatal_fr(r, "parse ispeed"); 382 if (failure != -1 && 383 cfsetispeed(&tio, baud_to_speed(baud)) == -1) 384 error("cfsetispeed failed for %d", baud); 385 break; 386 387 case TTY_OP_OSPEED: 388 if ((r = sshbuf_get_u32(buf, &baud)) != 0) 389 fatal_fr(r, "parse ospeed"); 390 if (failure != -1 && 391 cfsetospeed(&tio, baud_to_speed(baud)) == -1) 392 error("cfsetospeed failed for %d", baud); 393 break; 394 395 #define TTYCHAR(NAME, OP) \ 396 case OP: \ 397 if ((r = sshbuf_get_u32(buf, &u)) != 0) \ 398 fatal_fr(r, "parse %s", #NAME); \ 399 tio.c_cc[NAME] = special_char_decode(u); \ 400 break; 401 #define TTYMODE(NAME, FIELD, OP) \ 402 case OP: \ 403 if ((r = sshbuf_get_u32(buf, &u)) != 0) \ 404 fatal_fr(r, "parse %s", #NAME); \ 405 if (u) \ 406 tio.FIELD |= NAME; \ 407 else \ 408 tio.FIELD &= ~NAME; \ 409 break; 410 411 #include "ttymodes.h" 412 413 #undef TTYCHAR 414 #undef TTYMODE 415 416 default: 417 debug("Ignoring unsupported tty mode opcode %d (0x%x)", 418 opcode, opcode); 419 /* 420 * SSH2: 421 * Opcodes 1 to 159 are defined to have a uint32 422 * argument. 423 * Opcodes 160 to 255 are undefined and cause parsing 424 * to stop. 425 */ 426 if (opcode > 0 && opcode < 160) { 427 if ((r = sshbuf_get_u32(buf, NULL)) != 0) 428 fatal_fr(r, "parse arg"); 429 break; 430 } else { 431 logit_f("unknown opcode %d", opcode); 432 goto set; 433 } 434 } 435 } 436 437 set: 438 len = sshbuf_len(buf); 439 sshbuf_free(buf); 440 if (len > 0) { 441 logit_f("%zu bytes left", len); 442 return; /* Don't process bytes passed */ 443 } 444 if (failure == -1) 445 return; /* Packet parsed ok but tcgetattr() failed */ 446 447 /* Set the new modes for the terminal. */ 448 if (tcsetattr(fd, TCSANOW, &tio) == -1) 449 logit("Setting tty modes failed: %.100s", strerror(errno)); 450 } 451