| 1 | /* |
| 2 | * uxcons.c: various interactive-prompt routines shared between the |
| 3 | * Unix console PuTTY tools |
| 4 | */ |
| 5 | |
| 6 | #include <stdio.h> |
| 7 | #include <stdlib.h> |
| 8 | #include <stdarg.h> |
| 9 | #include <assert.h> |
| 10 | |
| 11 | #include <termios.h> |
| 12 | #include <unistd.h> |
| 13 | #include <fcntl.h> |
| 14 | |
| 15 | #include "putty.h" |
| 16 | #include "storage.h" |
| 17 | #include "ssh.h" |
| 18 | |
| 19 | int console_batch_mode = FALSE; |
| 20 | |
| 21 | static void *console_logctx = NULL; |
| 22 | |
| 23 | static struct termios orig_termios_stderr; |
| 24 | static int stderr_is_a_tty; |
| 25 | |
| 26 | void stderr_tty_init() |
| 27 | { |
| 28 | /* Ensure that if stderr is a tty, we can get it back to a sane state. */ |
| 29 | if ((flags & FLAG_STDERR_TTY) && isatty(STDERR_FILENO)) { |
| 30 | stderr_is_a_tty = TRUE; |
| 31 | tcgetattr(STDERR_FILENO, &orig_termios_stderr); |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | void premsg(struct termios *cf) |
| 36 | { |
| 37 | if (stderr_is_a_tty) { |
| 38 | tcgetattr(STDERR_FILENO, cf); |
| 39 | tcsetattr(STDERR_FILENO, TCSADRAIN, &orig_termios_stderr); |
| 40 | } |
| 41 | } |
| 42 | void postmsg(struct termios *cf) |
| 43 | { |
| 44 | if (stderr_is_a_tty) |
| 45 | tcsetattr(STDERR_FILENO, TCSADRAIN, cf); |
| 46 | } |
| 47 | |
| 48 | /* |
| 49 | * Clean up and exit. |
| 50 | */ |
| 51 | void cleanup_exit(int code) |
| 52 | { |
| 53 | /* |
| 54 | * Clean up. |
| 55 | */ |
| 56 | sk_cleanup(); |
| 57 | random_save_seed(); |
| 58 | exit(code); |
| 59 | } |
| 60 | |
| 61 | void set_busy_status(void *frontend, int status) |
| 62 | { |
| 63 | } |
| 64 | |
| 65 | void update_specials_menu(void *frontend) |
| 66 | { |
| 67 | } |
| 68 | |
| 69 | void notify_remote_exit(void *frontend) |
| 70 | { |
| 71 | } |
| 72 | |
| 73 | void timer_change_notify(long next) |
| 74 | { |
| 75 | } |
| 76 | |
| 77 | int verify_ssh_host_key(void *frontend, char *host, int port, char *keytype, |
| 78 | char *keystr, char *fingerprint, |
| 79 | void (*callback)(void *ctx, int result), void *ctx) |
| 80 | { |
| 81 | int ret; |
| 82 | |
| 83 | static const char absentmsg_batch[] = |
| 84 | "The server's host key is not cached. You have no guarantee\n" |
| 85 | "that the server is the computer you think it is.\n" |
| 86 | "The server's %s key fingerprint is:\n" |
| 87 | "%s\n" |
| 88 | "Connection abandoned.\n"; |
| 89 | static const char absentmsg[] = |
| 90 | "The server's host key is not cached. You have no guarantee\n" |
| 91 | "that the server is the computer you think it is.\n" |
| 92 | "The server's %s key fingerprint is:\n" |
| 93 | "%s\n" |
| 94 | "If you trust this host, enter \"y\" to add the key to\n" |
| 95 | "PuTTY's cache and carry on connecting.\n" |
| 96 | "If you want to carry on connecting just once, without\n" |
| 97 | "adding the key to the cache, enter \"n\".\n" |
| 98 | "If you do not trust this host, press Return to abandon the\n" |
| 99 | "connection.\n" |
| 100 | "Store key in cache? (y/n) "; |
| 101 | |
| 102 | static const char wrongmsg_batch[] = |
| 103 | "WARNING - POTENTIAL SECURITY BREACH!\n" |
| 104 | "The server's host key does not match the one PuTTY has\n" |
| 105 | "cached. This means that either the server administrator\n" |
| 106 | "has changed the host key, or you have actually connected\n" |
| 107 | "to another computer pretending to be the server.\n" |
| 108 | "The new %s key fingerprint is:\n" |
| 109 | "%s\n" |
| 110 | "Connection abandoned.\n"; |
| 111 | static const char wrongmsg[] = |
| 112 | "WARNING - POTENTIAL SECURITY BREACH!\n" |
| 113 | "The server's host key does not match the one PuTTY has\n" |
| 114 | "cached. This means that either the server administrator\n" |
| 115 | "has changed the host key, or you have actually connected\n" |
| 116 | "to another computer pretending to be the server.\n" |
| 117 | "The new %s key fingerprint is:\n" |
| 118 | "%s\n" |
| 119 | "If you were expecting this change and trust the new key,\n" |
| 120 | "enter \"y\" to update PuTTY's cache and continue connecting.\n" |
| 121 | "If you want to carry on connecting but without updating\n" |
| 122 | "the cache, enter \"n\".\n" |
| 123 | "If you want to abandon the connection completely, press\n" |
| 124 | "Return to cancel. Pressing Return is the ONLY guaranteed\n" |
| 125 | "safe choice.\n" |
| 126 | "Update cached key? (y/n, Return cancels connection) "; |
| 127 | |
| 128 | static const char abandoned[] = "Connection abandoned.\n"; |
| 129 | |
| 130 | char line[32]; |
| 131 | struct termios cf; |
| 132 | |
| 133 | /* |
| 134 | * Verify the key. |
| 135 | */ |
| 136 | ret = verify_host_key(host, port, keytype, keystr); |
| 137 | |
| 138 | if (ret == 0) /* success - key matched OK */ |
| 139 | return 1; |
| 140 | |
| 141 | premsg(&cf); |
| 142 | if (ret == 2) { /* key was different */ |
| 143 | if (console_batch_mode) { |
| 144 | fprintf(stderr, wrongmsg_batch, keytype, fingerprint); |
| 145 | return 0; |
| 146 | } |
| 147 | fprintf(stderr, wrongmsg, keytype, fingerprint); |
| 148 | fflush(stderr); |
| 149 | } |
| 150 | if (ret == 1) { /* key was absent */ |
| 151 | if (console_batch_mode) { |
| 152 | fprintf(stderr, absentmsg_batch, keytype, fingerprint); |
| 153 | return 0; |
| 154 | } |
| 155 | fprintf(stderr, absentmsg, keytype, fingerprint); |
| 156 | fflush(stderr); |
| 157 | } |
| 158 | |
| 159 | { |
| 160 | struct termios oldmode, newmode; |
| 161 | tcgetattr(0, &oldmode); |
| 162 | newmode = oldmode; |
| 163 | newmode.c_lflag |= ECHO | ISIG | ICANON; |
| 164 | tcsetattr(0, TCSANOW, &newmode); |
| 165 | line[0] = '\0'; |
| 166 | if (read(0, line, sizeof(line) - 1) <= 0) |
| 167 | /* handled below */; |
| 168 | tcsetattr(0, TCSANOW, &oldmode); |
| 169 | } |
| 170 | |
| 171 | if (line[0] != '\0' && line[0] != '\r' && line[0] != '\n') { |
| 172 | if (line[0] == 'y' || line[0] == 'Y') |
| 173 | store_host_key(host, port, keytype, keystr); |
| 174 | postmsg(&cf); |
| 175 | return 1; |
| 176 | } else { |
| 177 | fprintf(stderr, abandoned); |
| 178 | postmsg(&cf); |
| 179 | return 0; |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * Ask whether the selected algorithm is acceptable (since it was |
| 185 | * below the configured 'warn' threshold). |
| 186 | */ |
| 187 | int askalg(void *frontend, const char *algtype, const char *algname, |
| 188 | void (*callback)(void *ctx, int result), void *ctx) |
| 189 | { |
| 190 | static const char msg[] = |
| 191 | "The first %s supported by the server is\n" |
| 192 | "%s, which is below the configured warning threshold.\n" |
| 193 | "Continue with connection? (y/n) "; |
| 194 | static const char msg_batch[] = |
| 195 | "The first %s supported by the server is\n" |
| 196 | "%s, which is below the configured warning threshold.\n" |
| 197 | "Connection abandoned.\n"; |
| 198 | static const char abandoned[] = "Connection abandoned.\n"; |
| 199 | |
| 200 | char line[32]; |
| 201 | struct termios cf; |
| 202 | |
| 203 | premsg(&cf); |
| 204 | if (console_batch_mode) { |
| 205 | fprintf(stderr, msg_batch, algtype, algname); |
| 206 | return 0; |
| 207 | } |
| 208 | |
| 209 | fprintf(stderr, msg, algtype, algname); |
| 210 | fflush(stderr); |
| 211 | |
| 212 | { |
| 213 | struct termios oldmode, newmode; |
| 214 | tcgetattr(0, &oldmode); |
| 215 | newmode = oldmode; |
| 216 | newmode.c_lflag |= ECHO | ISIG | ICANON; |
| 217 | tcsetattr(0, TCSANOW, &newmode); |
| 218 | line[0] = '\0'; |
| 219 | if (read(0, line, sizeof(line) - 1) <= 0) |
| 220 | /* handled below */; |
| 221 | tcsetattr(0, TCSANOW, &oldmode); |
| 222 | } |
| 223 | |
| 224 | if (line[0] == 'y' || line[0] == 'Y') { |
| 225 | postmsg(&cf); |
| 226 | return 1; |
| 227 | } else { |
| 228 | fprintf(stderr, abandoned); |
| 229 | postmsg(&cf); |
| 230 | return 0; |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * Ask whether to wipe a session log file before writing to it. |
| 236 | * Returns 2 for wipe, 1 for append, 0 for cancel (don't log). |
| 237 | */ |
| 238 | int askappend(void *frontend, Filename *filename, |
| 239 | void (*callback)(void *ctx, int result), void *ctx) |
| 240 | { |
| 241 | static const char msgtemplate[] = |
| 242 | "The session log file \"%.*s\" already exists.\n" |
| 243 | "You can overwrite it with a new session log,\n" |
| 244 | "append your session log to the end of it,\n" |
| 245 | "or disable session logging for this session.\n" |
| 246 | "Enter \"y\" to wipe the file, \"n\" to append to it,\n" |
| 247 | "or just press Return to disable logging.\n" |
| 248 | "Wipe the log file? (y/n, Return cancels logging) "; |
| 249 | |
| 250 | static const char msgtemplate_batch[] = |
| 251 | "The session log file \"%.*s\" already exists.\n" |
| 252 | "Logging will not be enabled.\n"; |
| 253 | |
| 254 | char line[32]; |
| 255 | struct termios cf; |
| 256 | |
| 257 | premsg(&cf); |
| 258 | if (console_batch_mode) { |
| 259 | fprintf(stderr, msgtemplate_batch, FILENAME_MAX, filename->path); |
| 260 | fflush(stderr); |
| 261 | return 0; |
| 262 | } |
| 263 | fprintf(stderr, msgtemplate, FILENAME_MAX, filename->path); |
| 264 | fflush(stderr); |
| 265 | |
| 266 | { |
| 267 | struct termios oldmode, newmode; |
| 268 | tcgetattr(0, &oldmode); |
| 269 | newmode = oldmode; |
| 270 | newmode.c_lflag |= ECHO | ISIG | ICANON; |
| 271 | tcsetattr(0, TCSANOW, &newmode); |
| 272 | line[0] = '\0'; |
| 273 | if (read(0, line, sizeof(line) - 1) <= 0) |
| 274 | /* handled below */; |
| 275 | tcsetattr(0, TCSANOW, &oldmode); |
| 276 | } |
| 277 | |
| 278 | postmsg(&cf); |
| 279 | if (line[0] == 'y' || line[0] == 'Y') |
| 280 | return 2; |
| 281 | else if (line[0] == 'n' || line[0] == 'N') |
| 282 | return 1; |
| 283 | else |
| 284 | return 0; |
| 285 | } |
| 286 | |
| 287 | /* |
| 288 | * Warn about the obsolescent key file format. |
| 289 | * |
| 290 | * Uniquely among these functions, this one does _not_ expect a |
| 291 | * frontend handle. This means that if PuTTY is ported to a |
| 292 | * platform which requires frontend handles, this function will be |
| 293 | * an anomaly. Fortunately, the problem it addresses will not have |
| 294 | * been present on that platform, so it can plausibly be |
| 295 | * implemented as an empty function. |
| 296 | */ |
| 297 | void old_keyfile_warning(void) |
| 298 | { |
| 299 | static const char message[] = |
| 300 | "You are loading an SSH-2 private key which has an\n" |
| 301 | "old version of the file format. This means your key\n" |
| 302 | "file is not fully tamperproof. Future versions of\n" |
| 303 | "PuTTY may stop supporting this private key format,\n" |
| 304 | "so we recommend you convert your key to the new\n" |
| 305 | "format.\n" |
| 306 | "\n" |
| 307 | "Once the key is loaded into PuTTYgen, you can perform\n" |
| 308 | "this conversion simply by saving it again.\n"; |
| 309 | |
| 310 | struct termios cf; |
| 311 | premsg(&cf); |
| 312 | fputs(message, stderr); |
| 313 | postmsg(&cf); |
| 314 | } |
| 315 | |
| 316 | void console_provide_logctx(void *logctx) |
| 317 | { |
| 318 | console_logctx = logctx; |
| 319 | } |
| 320 | |
| 321 | void logevent(void *frontend, const char *string) |
| 322 | { |
| 323 | struct termios cf; |
| 324 | premsg(&cf); |
| 325 | if (console_logctx) |
| 326 | log_eventlog(console_logctx, string); |
| 327 | postmsg(&cf); |
| 328 | } |
| 329 | |
| 330 | /* |
| 331 | * Special functions to read and print to the console for password |
| 332 | * prompts and the like. Uses /dev/tty or stdin/stderr, in that order |
| 333 | * of preference; also sanitises escape sequences out of the text, on |
| 334 | * the basis that it might have been sent by a hostile SSH server |
| 335 | * doing malicious keyboard-interactive. |
| 336 | */ |
| 337 | static void console_open(FILE **outfp, int *infd) |
| 338 | { |
| 339 | int fd; |
| 340 | |
| 341 | if ((fd = open("/dev/tty", O_RDWR)) >= 0) { |
| 342 | *infd = fd; |
| 343 | *outfp = fdopen(*infd, "w"); |
| 344 | } else { |
| 345 | *infd = 0; |
| 346 | *outfp = stderr; |
| 347 | } |
| 348 | } |
| 349 | static void console_close(FILE *outfp, int infd) |
| 350 | { |
| 351 | if (outfp != stderr) |
| 352 | fclose(outfp); /* will automatically close infd too */ |
| 353 | } |
| 354 | |
| 355 | static void console_prompt_text(FILE *outfp, const char *data, int len) |
| 356 | { |
| 357 | int i; |
| 358 | |
| 359 | for (i = 0; i < len; i++) |
| 360 | if ((data[i] & 0x60) || (data[i] == '\n')) |
| 361 | fputc(data[i], outfp); |
| 362 | fflush(outfp); |
| 363 | } |
| 364 | |
| 365 | int console_get_userpass_input(prompts_t *p, unsigned char *in, int inlen) |
| 366 | { |
| 367 | size_t curr_prompt; |
| 368 | FILE *outfp = NULL; |
| 369 | int infd; |
| 370 | |
| 371 | /* |
| 372 | * Zero all the results, in case we abort half-way through. |
| 373 | */ |
| 374 | { |
| 375 | int i; |
| 376 | for (i = 0; i < p->n_prompts; i++) |
| 377 | memset(p->prompts[i]->result, 0, p->prompts[i]->result_len); |
| 378 | } |
| 379 | |
| 380 | if (p->n_prompts && console_batch_mode) |
| 381 | return 0; |
| 382 | |
| 383 | console_open(&outfp, &infd); |
| 384 | |
| 385 | /* |
| 386 | * Preamble. |
| 387 | */ |
| 388 | /* We only print the `name' caption if we have to... */ |
| 389 | if (p->name_reqd && p->name) { |
| 390 | size_t l = strlen(p->name); |
| 391 | console_prompt_text(outfp, p->name, l); |
| 392 | if (p->name[l-1] != '\n') |
| 393 | console_prompt_text(outfp, "\n", 1); |
| 394 | } |
| 395 | /* ...but we always print any `instruction'. */ |
| 396 | if (p->instruction) { |
| 397 | size_t l = strlen(p->instruction); |
| 398 | console_prompt_text(outfp, p->instruction, l); |
| 399 | if (p->instruction[l-1] != '\n') |
| 400 | console_prompt_text(outfp, "\n", 1); |
| 401 | } |
| 402 | |
| 403 | for (curr_prompt = 0; curr_prompt < p->n_prompts; curr_prompt++) { |
| 404 | |
| 405 | struct termios oldmode, newmode; |
| 406 | int i; |
| 407 | prompt_t *pr = p->prompts[curr_prompt]; |
| 408 | |
| 409 | tcgetattr(infd, &oldmode); |
| 410 | newmode = oldmode; |
| 411 | newmode.c_lflag |= ISIG | ICANON; |
| 412 | if (!pr->echo) |
| 413 | newmode.c_lflag &= ~ECHO; |
| 414 | else |
| 415 | newmode.c_lflag |= ECHO; |
| 416 | tcsetattr(infd, TCSANOW, &newmode); |
| 417 | |
| 418 | console_prompt_text(outfp, pr->prompt, strlen(pr->prompt)); |
| 419 | |
| 420 | i = read(infd, pr->result, pr->result_len - 1); |
| 421 | |
| 422 | tcsetattr(infd, TCSANOW, &oldmode); |
| 423 | |
| 424 | if (i > 0 && pr->result[i-1] == '\n') |
| 425 | i--; |
| 426 | pr->result[i] = '\0'; |
| 427 | |
| 428 | if (!pr->echo) |
| 429 | console_prompt_text(outfp, "\n", 1); |
| 430 | |
| 431 | } |
| 432 | |
| 433 | console_close(outfp, infd); |
| 434 | |
| 435 | return 1; /* success */ |
| 436 | } |
| 437 | |
| 438 | void frontend_keypress(void *handle) |
| 439 | { |
| 440 | /* |
| 441 | * This is nothing but a stub, in console code. |
| 442 | */ |
| 443 | return; |
| 444 | } |
| 445 | |
| 446 | int is_interactive(void) |
| 447 | { |
| 448 | return isatty(0); |
| 449 | } |
| 450 | |
| 451 | /* |
| 452 | * X11-forwarding-related things suitable for console. |
| 453 | */ |
| 454 | |
| 455 | char *platform_get_x_display(void) { |
| 456 | return dupstr(getenv("DISPLAY")); |
| 457 | } |