1 /* $NetBSD: getpass.c,v 1.27 2012/05/26 19:34:16 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2012 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 #include <sys/cdefs.h> 32 #if defined(LIBC_SCCS) && !defined(lint) 33 __RCSID("$NetBSD: getpass.c,v 1.27 2012/05/26 19:34:16 christos Exp $"); 34 #endif /* LIBC_SCCS and not lint */ 35 36 #include "namespace.h" 37 38 #include <assert.h> 39 #ifdef TEST 40 #include <stdio.h> 41 #endif 42 #include <errno.h> 43 #include <ctype.h> 44 #include <signal.h> 45 #include <string.h> 46 #include <paths.h> 47 #include <stdbool.h> 48 #include <stdlib.h> 49 #include <termios.h> 50 #include <unistd.h> 51 #include <fcntl.h> 52 #include <poll.h> 53 54 #ifdef __weak_alias 55 __weak_alias(getpassfd,_getpassfd) 56 __weak_alias(getpass_r,_getpass_r) 57 __weak_alias(getpass,_getpass) 58 #endif 59 60 /* 61 * Notes: 62 * - There is no getpass_r in POSIX 63 * - Historically EOF is documented to be treated as EOL, we provide a 64 * tunable for that GETPASS_FAIL_EOF to disable this. 65 * - Historically getpass ate extra characters silently, we provide 66 * a tunable for that GETPASS_BUF_LIMIT to disable this. 67 * - Historically getpass "worked" by echoing characters when turning 68 * off echo failed, we provide a tunable GETPASS_NEED_TTY to 69 * disable this. 70 * - Some implementations say that on interrupt the program shall 71 * receive an interrupt signal before the function returns. We 72 * send all the tty signals before we return, but we don't expect 73 * suspend to do something useful unless the caller calls us again. 74 * We also provide a tunable to disable signal delivery 75 * GETPASS_NO_SIGNAL. 76 * - GETPASS_NO_BEEP disables beeping. 77 * - GETPASS_ECHO_STAR will echo '*' for each character of the password 78 * - GETPASS_ECHO will echo the password (as pam likes it) 79 * - GETPASS_7BIT strips the 8th bit 80 * - GETPASS_FORCE_UPPER forces to uppercase 81 * - GETPASS_FORCE_LOWER forces to uppercase 82 * - GETPASS_ECHO_NL echo's a new line on success if echo was off. 83 */ 84 char * 85 /*ARGSUSED*/ 86 getpassfd(const char *prompt, char *buf, size_t len, int *fd, int flags, 87 int tout) 88 { 89 struct termios gt; 90 char c; 91 int sig; 92 bool lnext, havetty, allocated, opentty, good; 93 int fdc[3]; 94 95 _DIAGASSERT(prompt != NULL); 96 97 if (buf != NULL && len == 0) { 98 errno = EINVAL; 99 return NULL; 100 } 101 102 good = false; 103 opentty = false; 104 if (fd == NULL) { 105 /* 106 * Try to use /dev/tty if possible; otherwise read from stdin 107 * and write to stderr. 108 */ 109 fd = fdc; 110 if ((fd[0] = fd[1] = fd[2] = open(_PATH_TTY, O_RDWR)) == -1) { 111 fd[0] = STDIN_FILENO; 112 fd[1] = fd[2] = STDERR_FILENO; 113 } else 114 opentty = true; 115 } 116 117 sig = 0; 118 allocated = buf == NULL; 119 if (tcgetattr(fd[0], >) == -1) { 120 havetty = false; 121 if (flags & GETPASS_NEED_TTY) 122 goto out; 123 memset(>, -1, sizeof(gt)); 124 } else 125 havetty = true; 126 127 if (havetty) { 128 struct termios st = gt; 129 130 st.c_lflag &= ~(ECHO|ECHOK|ECHOE|ECHOKE|ECHOCTL|ISIG|ICANON); 131 st.c_cc[VMIN] = 1; 132 st.c_cc[VTIME] = 0; 133 if (tcsetattr(fd[0], TCSAFLUSH|TCSASOFT, &st) == -1) 134 goto out; 135 } 136 137 if (prompt != NULL) { 138 size_t plen = strlen(prompt); 139 (void)write(fd[1], prompt, plen); 140 } 141 142 if (allocated) { 143 len = 1024; 144 if ((buf = malloc(len)) == NULL) 145 goto restore; 146 } 147 148 c = '\1'; 149 lnext = false; 150 for (size_t l = 0; c != '\0'; ) { 151 if (tout) { 152 struct pollfd pfd; 153 pfd.fd = fd[0]; 154 pfd.events = POLLIN|POLLRDNORM; 155 pfd.revents = 0; 156 switch (poll(&pfd, 1, tout * 1000)) { 157 case 0: 158 errno = ETIMEDOUT; 159 /*FALLTHROUGH*/ 160 case -1: 161 goto restore; 162 default: 163 break; 164 } 165 } 166 if (read(fd[0], &c, 1) != 1) 167 goto restore; 168 169 #define beep() \ 170 do \ 171 if (flags & GETPASS_NO_BEEP) \ 172 (void)write(fd[2], "\a", 1); \ 173 while (/*CONSTCOND*/ 0) 174 #define erase() (void)write(fd[1], "\b \b", 3) 175 /* 176 * We test for both _POSIX_VDISABLE and NUL here because _POSIX_VDISABLE 177 * propagation does not seem to be very consistent on multiple daemon hops 178 * between different OS's. Perhaps we should not even bother with 179 * _POSIX_VDISABLE and use ~0 and 0 directly. 180 */ 181 #define C(a, b) ((gt.c_cc[(a)] == _POSIX_VDISABLE || gt.c_cc[(a)] == '\0') ? \ 182 (b) : gt.c_cc[(a)]) 183 if (lnext) { 184 lnext = false; 185 goto add; 186 } 187 188 /* Ignored */ 189 if (c == C(VREPRINT, CTRL('r')) || c == C(VSTART, CTRL('q')) || 190 c == C(VSTOP, CTRL('s')) || c == C(VSTATUS, CTRL('t')) || 191 c == C(VDISCARD, CTRL('o'))) 192 continue; 193 194 /* Literal next */ 195 if (c == C(VLNEXT, CTRL('v'))) { 196 lnext = true; 197 continue; 198 } 199 200 /* Line or word kill, treat as reset */ 201 if (c == C(VKILL, CTRL('u')) || c == C(VWERASE, CTRL('w'))) { 202 if (flags & (GETPASS_ECHO | GETPASS_ECHO_STAR)) { 203 while (l--) 204 erase(); 205 } 206 l = 0; 207 continue; 208 } 209 210 /* Character erase */ 211 if (c == C(VERASE, CTRL('h'))) { 212 if (l == 0) 213 beep(); 214 else { 215 l--; 216 if (flags & (GETPASS_ECHO | GETPASS_ECHO_STAR)) 217 erase(); 218 } 219 continue; 220 } 221 222 /* tty signal characters */ 223 if (c == C(VINTR, CTRL('c'))) { 224 sig = SIGINT; 225 goto out; 226 } 227 if (c == C(VQUIT, CTRL('\\'))) { 228 sig = SIGQUIT; 229 goto out; 230 } 231 if (c == C(VSUSP, CTRL('z')) || c == C(VDSUSP, CTRL('y'))) { 232 sig = SIGTSTP; 233 goto out; 234 } 235 236 /* EOF */ 237 if (c == C(VEOF, CTRL('d'))) { 238 if (flags & GETPASS_FAIL_EOF) { 239 errno = ENODATA; 240 goto out; 241 } else { 242 c = '\0'; 243 goto add; 244 } 245 } 246 247 /* End of line */ 248 if (c == C(VEOL, CTRL('j')) || c == C(VEOL2, CTRL('l'))) 249 c = '\0'; 250 add: 251 if (l >= len) { 252 if (allocated) { 253 size_t nlen = len + 1024; 254 char *nbuf = realloc(buf, nlen); 255 if (nbuf == NULL) 256 goto restore; 257 buf = nbuf; 258 len = nlen; 259 } else { 260 if (flags & GETPASS_BUF_LIMIT) { 261 beep(); 262 continue; 263 } 264 if (c == '\0' && l > 0) 265 l--; 266 else 267 continue; 268 } 269 } 270 271 if (flags & GETPASS_7BIT) 272 c &= 0x7f; 273 if ((flags & GETPASS_FORCE_LOWER) && isupper((unsigned char)c)) 274 c = tolower((unsigned char)c); 275 if ((flags & GETPASS_FORCE_UPPER) && islower((unsigned char)c)) 276 c = toupper((unsigned char)c); 277 278 buf[l++] = c; 279 if (c) { 280 if (flags & GETPASS_ECHO_STAR) 281 (void)write(fd[1], "*", 1); 282 else if (flags & GETPASS_ECHO) 283 (void)write(fd[1], isprint((unsigned char)c) ? 284 &c : "?", 1); 285 } 286 } 287 good = true; 288 289 restore: 290 if (havetty) { 291 c = errno; 292 (void)tcsetattr(fd[0], TCSAFLUSH|TCSASOFT, >); 293 errno = c; 294 } 295 out: 296 if (good && (flags & GETPASS_ECHO_NL)) 297 (void)write(fd[1], "\n", 1); 298 299 if (opentty) { 300 c = errno; 301 (void)close(fd[0]); 302 errno = c; 303 } 304 305 if (good) 306 return buf; 307 308 if (sig) { 309 if ((flags & GETPASS_NO_SIGNAL) == 0) 310 (void)raise(sig); 311 errno = EINTR; 312 } 313 memset(buf, 0, len); 314 if (allocated) 315 free(buf); 316 return NULL; 317 } 318 319 char * 320 getpass_r(const char *prompt, char *buf, size_t len) 321 { 322 return getpassfd(prompt, buf, len, NULL, GETPASS_ECHO_NL, 0); 323 } 324 325 char * 326 getpass(const char *prompt) 327 { 328 static char e[] = ""; 329 static char *buf; 330 static long bufsiz; 331 char *rv; 332 333 /* 334 * Strictly speaking we could double allocate here, if we get 335 * called at the same time, but this function is not re-entrant 336 * anyway and it is not supposed to work if called concurrently. 337 */ 338 if (buf == NULL) { 339 if ((bufsiz = sysconf(_SC_PASS_MAX)) == -1) 340 return e; 341 if ((buf = malloc((size_t)bufsiz)) == NULL) 342 return e; 343 } 344 345 if ((rv = getpass_r(prompt, buf, (size_t)bufsiz)) == NULL) 346 return e; 347 348 return rv; 349 } 350 351 #ifdef TEST 352 int 353 main(int argc, char *argv[]) 354 { 355 char buf[28]; 356 printf("[%s]\n", getpassfd("foo>", buf, sizeof(buf), NULL, 357 GETPASS_ECHO_STAR|GETPASS_ECHO_NL, 2)); 358 return 0; 359 } 360 #endif 361