| 1 | #define _XOPEN_SOURCE |
| 2 | #define _XOPEN_SOURCE_EXTENDED |
| 3 | #include <features.h> |
| 4 | |
| 5 | #include <stdio.h> |
| 6 | #include <stdlib.h> |
| 7 | #include <string.h> |
| 8 | #include <unistd.h> |
| 9 | #include <signal.h> |
| 10 | #include <fcntl.h> |
| 11 | #include <termios.h> |
| 12 | #include <grp.h> |
| 13 | #include <utmp.h> |
| 14 | #include <pwd.h> |
| 15 | #include <time.h> |
| 16 | #include <sys/types.h> |
| 17 | #include <sys/wait.h> |
| 18 | #include <sys/ioctl.h> |
| 19 | |
| 20 | #include "putty.h" |
| 21 | |
| 22 | #ifndef FALSE |
| 23 | #define FALSE 0 |
| 24 | #endif |
| 25 | #ifndef TRUE |
| 26 | #define TRUE 1 |
| 27 | #endif |
| 28 | |
| 29 | #ifndef UTMP_FILE |
| 30 | #define UTMP_FILE "/var/run/utmp" |
| 31 | #endif |
| 32 | #ifndef WTMP_FILE |
| 33 | #define WTMP_FILE "/var/log/wtmp" |
| 34 | #endif |
| 35 | #ifndef LASTLOG_FILE |
| 36 | #ifdef _PATH_LASTLOG |
| 37 | #define LASTLOG_FILE _PATH_LASTLOG |
| 38 | #else |
| 39 | #define LASTLOG_FILE "/var/log/lastlog" |
| 40 | #endif |
| 41 | #endif |
| 42 | |
| 43 | /* |
| 44 | * Set up a default for vaguely sane systems. The idea is that if |
| 45 | * OMIT_UTMP is not defined, then at least one of the symbols which |
| 46 | * enable particular forms of utmp processing should be, if only so |
| 47 | * that a link error can warn you that you should have defined |
| 48 | * OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is |
| 49 | * the only such symbol. |
| 50 | */ |
| 51 | #ifndef OMIT_UTMP |
| 52 | #if !defined HAVE_PUTUTLINE |
| 53 | #define HAVE_PUTUTLINE |
| 54 | #endif |
| 55 | #endif |
| 56 | |
| 57 | int pty_master_fd; |
| 58 | int pty_stamp_utmp = 1; |
| 59 | static int pty_stamped_utmp = 0; |
| 60 | static int pty_child_pid; |
| 61 | static sig_atomic_t pty_child_dead; |
| 62 | #ifndef OMIT_UTMP |
| 63 | static struct utmp utmp_entry; |
| 64 | #endif |
| 65 | char **pty_argv; |
| 66 | |
| 67 | int pty_child_is_dead(void) |
| 68 | { |
| 69 | return pty_child_dead; |
| 70 | } |
| 71 | |
| 72 | static void pty_size(void); |
| 73 | |
| 74 | static void setup_utmp(char *ttyname) |
| 75 | { |
| 76 | #ifndef OMIT_UTMP |
| 77 | #ifdef HAVE_LASTLOG |
| 78 | struct lastlog lastlog_entry; |
| 79 | FILE *lastlog; |
| 80 | #endif |
| 81 | struct passwd *pw; |
| 82 | char *location; |
| 83 | FILE *wtmp; |
| 84 | |
| 85 | if (!pty_stamp_utmp) |
| 86 | return; |
| 87 | |
| 88 | pw = getpwuid(getuid()); |
| 89 | location = get_x_display(); |
| 90 | memset(&utmp_entry, 0, sizeof(utmp_entry)); |
| 91 | utmp_entry.ut_type = USER_PROCESS; |
| 92 | utmp_entry.ut_pid = getpid(); |
| 93 | strncpy(utmp_entry.ut_line, ttyname+5, lenof(utmp_entry.ut_line)); |
| 94 | strncpy(utmp_entry.ut_id, ttyname+8, lenof(utmp_entry.ut_id)); |
| 95 | strncpy(utmp_entry.ut_user, pw->pw_name, lenof(utmp_entry.ut_user)); |
| 96 | strncpy(utmp_entry.ut_host, location, lenof(utmp_entry.ut_host)); |
| 97 | time(&utmp_entry.ut_time); |
| 98 | |
| 99 | #if defined HAVE_PUTUTLINE |
| 100 | utmpname(UTMP_FILE); |
| 101 | setutent(); |
| 102 | pututline(&utmp_entry); |
| 103 | endutent(); |
| 104 | #endif |
| 105 | |
| 106 | if ((wtmp = fopen(WTMP_FILE, "a")) != NULL) { |
| 107 | fwrite(&utmp_entry, 1, sizeof(utmp_entry), wtmp); |
| 108 | fclose(wtmp); |
| 109 | } |
| 110 | |
| 111 | #ifdef HAVE_LASTLOG |
| 112 | memset(&lastlog_entry, 0, sizeof(lastlog_entry)); |
| 113 | strncpy(lastlog_entry.ll_line, ttyname+5, lenof(lastlog_entry.ll_line)); |
| 114 | strncpy(lastlog_entry.ll_host, location, lenof(lastlog_entry.ll_host)); |
| 115 | time(&lastlog_entry.ll_time); |
| 116 | if ((lastlog = fopen(LASTLOG_FILE, "r+")) != NULL) { |
| 117 | fseek(lastlog, sizeof(lastlog_entry) * getuid(), SEEK_SET); |
| 118 | fwrite(&lastlog_entry, 1, sizeof(lastlog_entry), lastlog); |
| 119 | fclose(lastlog); |
| 120 | } |
| 121 | #endif |
| 122 | |
| 123 | pty_stamped_utmp = 1; |
| 124 | |
| 125 | #endif |
| 126 | } |
| 127 | |
| 128 | static void cleanup_utmp(void) |
| 129 | { |
| 130 | #ifndef OMIT_UTMP |
| 131 | FILE *wtmp; |
| 132 | |
| 133 | if (!pty_stamp_utmp || !pty_stamped_utmp) |
| 134 | return; |
| 135 | |
| 136 | utmp_entry.ut_type = DEAD_PROCESS; |
| 137 | memset(utmp_entry.ut_user, 0, lenof(utmp_entry.ut_user)); |
| 138 | time(&utmp_entry.ut_time); |
| 139 | |
| 140 | if ((wtmp = fopen(WTMP_FILE, "a")) != NULL) { |
| 141 | fwrite(&utmp_entry, 1, sizeof(utmp_entry), wtmp); |
| 142 | fclose(wtmp); |
| 143 | } |
| 144 | |
| 145 | memset(utmp_entry.ut_line, 0, lenof(utmp_entry.ut_line)); |
| 146 | utmp_entry.ut_time = 0; |
| 147 | |
| 148 | #if defined HAVE_PUTUTLINE |
| 149 | utmpname(UTMP_FILE); |
| 150 | setutent(); |
| 151 | pututline(&utmp_entry); |
| 152 | endutent(); |
| 153 | #endif |
| 154 | |
| 155 | pty_stamped_utmp = 0; /* ensure we never double-cleanup */ |
| 156 | #endif |
| 157 | } |
| 158 | |
| 159 | static void sigchld_handler(int signum) |
| 160 | { |
| 161 | pid_t pid; |
| 162 | int status; |
| 163 | pid = waitpid(-1, &status, WNOHANG); |
| 164 | if (pid == pty_child_pid && (WIFEXITED(status) || WIFSIGNALED(status))) |
| 165 | pty_child_dead = TRUE; |
| 166 | } |
| 167 | |
| 168 | static void fatal_sig_handler(int signum) |
| 169 | { |
| 170 | signal(signum, SIG_DFL); |
| 171 | cleanup_utmp(); |
| 172 | setuid(getuid()); |
| 173 | raise(signum); |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * Called to set up the pty. |
| 178 | * |
| 179 | * Returns an error message, or NULL on success. |
| 180 | * |
| 181 | * Also places the canonical host name into `realhost'. It must be |
| 182 | * freed by the caller. |
| 183 | */ |
| 184 | static char *pty_init(char *host, int port, char **realhost, int nodelay) |
| 185 | { |
| 186 | int slavefd; |
| 187 | char name[FILENAME_MAX]; |
| 188 | pid_t pid, pgrp; |
| 189 | |
| 190 | #ifdef BSD_PTYS |
| 191 | { |
| 192 | const char chars1[] = "pqrstuvwxyz"; |
| 193 | const char chars2[] = "0123456789abcdef"; |
| 194 | const char *p1, *p2; |
| 195 | char master_name[20]; |
| 196 | |
| 197 | for (p1 = chars1; *p1; p1++) |
| 198 | for (p2 = chars2; *p2; p2++) { |
| 199 | sprintf(master_name, "/dev/pty%c%c", *p1, *p2); |
| 200 | pty_master_fd = open(master_name, O_RDWR); |
| 201 | if (pty_master_fd >= 0) { |
| 202 | if (geteuid() == 0 || |
| 203 | access(master_name, R_OK | W_OK) == 0) |
| 204 | goto got_one; |
| 205 | close(pty_master_fd); |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | /* If we get here, we couldn't get a tty at all. */ |
| 210 | fprintf(stderr, "pterm: unable to open a pseudo-terminal device\n"); |
| 211 | exit(1); |
| 212 | |
| 213 | got_one: |
| 214 | strcpy(name, master_name); |
| 215 | name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */ |
| 216 | } |
| 217 | #else |
| 218 | pty_master_fd = open("/dev/ptmx", O_RDWR); |
| 219 | |
| 220 | if (pty_master_fd < 0) { |
| 221 | perror("/dev/ptmx: open"); |
| 222 | exit(1); |
| 223 | } |
| 224 | |
| 225 | if (grantpt(pty_master_fd) < 0) { |
| 226 | perror("grantpt"); |
| 227 | exit(1); |
| 228 | } |
| 229 | |
| 230 | if (unlockpt(pty_master_fd) < 0) { |
| 231 | perror("unlockpt"); |
| 232 | exit(1); |
| 233 | } |
| 234 | |
| 235 | name[FILENAME_MAX-1] = '\0'; |
| 236 | strncpy(name, ptsname(pty_master_fd), FILENAME_MAX-1); |
| 237 | #endif |
| 238 | |
| 239 | /* |
| 240 | * Trap as many fatal signals as we can in the hope of having |
| 241 | * the best chance to clean up utmp before termination. |
| 242 | */ |
| 243 | signal(SIGHUP, fatal_sig_handler); |
| 244 | signal(SIGINT, fatal_sig_handler); |
| 245 | signal(SIGQUIT, fatal_sig_handler); |
| 246 | signal(SIGILL, fatal_sig_handler); |
| 247 | signal(SIGABRT, fatal_sig_handler); |
| 248 | signal(SIGFPE, fatal_sig_handler); |
| 249 | signal(SIGPIPE, fatal_sig_handler); |
| 250 | signal(SIGALRM, fatal_sig_handler); |
| 251 | signal(SIGTERM, fatal_sig_handler); |
| 252 | signal(SIGSEGV, fatal_sig_handler); |
| 253 | signal(SIGUSR1, fatal_sig_handler); |
| 254 | signal(SIGUSR2, fatal_sig_handler); |
| 255 | #ifdef SIGBUS |
| 256 | signal(SIGBUS, fatal_sig_handler); |
| 257 | #endif |
| 258 | #ifdef SIGPOLL |
| 259 | signal(SIGPOLL, fatal_sig_handler); |
| 260 | #endif |
| 261 | #ifdef SIGPROF |
| 262 | signal(SIGPROF, fatal_sig_handler); |
| 263 | #endif |
| 264 | #ifdef SIGSYS |
| 265 | signal(SIGSYS, fatal_sig_handler); |
| 266 | #endif |
| 267 | #ifdef SIGTRAP |
| 268 | signal(SIGTRAP, fatal_sig_handler); |
| 269 | #endif |
| 270 | #ifdef SIGVTALRM |
| 271 | signal(SIGVTALRM, fatal_sig_handler); |
| 272 | #endif |
| 273 | #ifdef SIGXCPU |
| 274 | signal(SIGXCPU, fatal_sig_handler); |
| 275 | #endif |
| 276 | #ifdef SIGXFSZ |
| 277 | signal(SIGXFSZ, fatal_sig_handler); |
| 278 | #endif |
| 279 | #ifdef SIGIO |
| 280 | signal(SIGIO, fatal_sig_handler); |
| 281 | #endif |
| 282 | /* Also clean up utmp on normal exit. */ |
| 283 | atexit(cleanup_utmp); |
| 284 | setup_utmp(name); |
| 285 | |
| 286 | /* |
| 287 | * Fork and execute the command. |
| 288 | */ |
| 289 | pid = fork(); |
| 290 | if (pid < 0) { |
| 291 | perror("fork"); |
| 292 | exit(1); |
| 293 | } |
| 294 | |
| 295 | if (pid == 0) { |
| 296 | int i; |
| 297 | /* |
| 298 | * We are the child. |
| 299 | */ |
| 300 | |
| 301 | slavefd = open(name, O_RDWR); |
| 302 | if (slavefd < 0) { |
| 303 | perror("slave pty: open"); |
| 304 | exit(1); |
| 305 | } |
| 306 | |
| 307 | #ifdef BSD_PTYS |
| 308 | /* We need to chown/chmod the /dev/ttyXX device. */ |
| 309 | { |
| 310 | struct group *gp = getgrnam("tty"); |
| 311 | fchown(slavefd, getuid(), gp ? gp->gr_gid : -1); |
| 312 | fchmod(slavefd, 0600); |
| 313 | } |
| 314 | #endif |
| 315 | |
| 316 | close(pty_master_fd); |
| 317 | close(0); |
| 318 | close(1); |
| 319 | close(2); |
| 320 | fcntl(slavefd, F_SETFD, 0); /* don't close on exec */ |
| 321 | dup2(slavefd, 0); |
| 322 | dup2(slavefd, 1); |
| 323 | dup2(slavefd, 2); |
| 324 | setsid(); |
| 325 | ioctl(slavefd, TIOCSCTTY, 1); |
| 326 | pgrp = getpid(); |
| 327 | tcsetpgrp(slavefd, pgrp); |
| 328 | setpgrp(); |
| 329 | close(open(name, O_WRONLY, 0)); |
| 330 | setpgrp(); |
| 331 | /* In case we were setgid-utmp or setuid-root, drop privs. */ |
| 332 | setgid(getgid()); |
| 333 | setuid(getuid()); |
| 334 | /* Close everything _else_, for tidiness. */ |
| 335 | for (i = 3; i < 1024; i++) |
| 336 | close(i); |
| 337 | { |
| 338 | char term_env_var[10 + sizeof(cfg.termtype)]; |
| 339 | sprintf(term_env_var, "TERM=%s", cfg.termtype); |
| 340 | putenv(term_env_var); |
| 341 | } |
| 342 | if (pty_argv) |
| 343 | execvp(pty_argv[0], pty_argv); |
| 344 | else |
| 345 | execl(getenv("SHELL"), getenv("SHELL"), NULL); |
| 346 | /* |
| 347 | * If we're here, exec has gone badly foom. |
| 348 | */ |
| 349 | perror("exec"); |
| 350 | exit(127); |
| 351 | } else { |
| 352 | close(slavefd); |
| 353 | pty_child_pid = pid; |
| 354 | pty_child_dead = FALSE; |
| 355 | signal(SIGCHLD, sigchld_handler); |
| 356 | } |
| 357 | |
| 358 | return NULL; |
| 359 | } |
| 360 | |
| 361 | /* |
| 362 | * Called to send data down the pty. |
| 363 | */ |
| 364 | static int pty_send(char *buf, int len) |
| 365 | { |
| 366 | while (len > 0) { |
| 367 | int ret = write(pty_master_fd, buf, len); |
| 368 | if (ret < 0) { |
| 369 | perror("write pty master"); |
| 370 | exit(1); |
| 371 | } |
| 372 | buf += ret; |
| 373 | len -= ret; |
| 374 | } |
| 375 | return 0; |
| 376 | } |
| 377 | |
| 378 | /* |
| 379 | * Called to query the current socket sendability status. |
| 380 | */ |
| 381 | static int pty_sendbuffer(void) |
| 382 | { |
| 383 | return 0; |
| 384 | } |
| 385 | |
| 386 | /* |
| 387 | * Called to set the size of the window |
| 388 | */ |
| 389 | static void pty_size(void) |
| 390 | { |
| 391 | struct winsize size; |
| 392 | |
| 393 | size.ws_row = (unsigned short)rows; |
| 394 | size.ws_col = (unsigned short)cols; |
| 395 | ioctl(pty_master_fd, TIOCSWINSZ, (void *)&size); |
| 396 | return; |
| 397 | } |
| 398 | |
| 399 | /* |
| 400 | * Send special codes. |
| 401 | */ |
| 402 | static void pty_special(Telnet_Special code) |
| 403 | { |
| 404 | /* Do nothing! */ |
| 405 | return; |
| 406 | } |
| 407 | |
| 408 | static Socket pty_socket(void) |
| 409 | { |
| 410 | return NULL; /* shouldn't ever be needed */ |
| 411 | } |
| 412 | |
| 413 | static int pty_sendok(void) |
| 414 | { |
| 415 | return 1; |
| 416 | } |
| 417 | |
| 418 | static void pty_unthrottle(int backlog) |
| 419 | { |
| 420 | /* do nothing */ |
| 421 | } |
| 422 | |
| 423 | static int pty_ldisc(int option) |
| 424 | { |
| 425 | return 0; /* neither editing nor echoing */ |
| 426 | } |
| 427 | |
| 428 | static int pty_exitcode(void) |
| 429 | { |
| 430 | /* Shouldn't ever be required */ |
| 431 | return 0; |
| 432 | } |
| 433 | |
| 434 | Backend pty_backend = { |
| 435 | pty_init, |
| 436 | pty_send, |
| 437 | pty_sendbuffer, |
| 438 | pty_size, |
| 439 | pty_special, |
| 440 | pty_socket, |
| 441 | pty_exitcode, |
| 442 | pty_sendok, |
| 443 | pty_ldisc, |
| 444 | pty_unthrottle, |
| 445 | 1 |
| 446 | }; |