2 * Copyright (c) 1993-1996,1998-2005, 2007-2011
3 * Todd C. Miller <Todd.Miller@courtesan.com>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 * Sponsored in part by the Defense Advanced Research Projects
18 * Agency (DARPA) and Air Force Research Laboratory, Air Force
19 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
24 #include <sys/types.h>
25 #include <sys/param.h>
31 #if defined(__sun) && defined(__SVR4)
32 # include <sys/statvfs.h>
35 # include <sys/file.h>
45 #endif /* STDC_HEADERS */
48 #endif /* HAVE_STRING_H */
51 #endif /* HAVE_STRINGS_H */
54 #endif /* HAVE_UNISTD_H */
55 #if TIME_WITH_SYS_TIME
66 /* Status codes for timestamp_status() */
73 /* Flags for timestamp_status() */
74 #define TS_MAKE_DIRS 1
78 * Info stored in tty ticket from stat(2) to help with tty matching.
80 static struct tty_info {
81 dev_t dev; /* ID of device tty resides on */
82 dev_t rdev; /* tty device ID */
83 ino_t ino; /* tty inode number */
84 struct timeval ctime; /* tty inode change time */
87 static int build_timestamp(char **, char **);
88 static int timestamp_status(char *, char *, char *, int);
89 static char *expand_prompt(char *, char *, char *);
90 static void lecture(int);
91 static void update_timestamp(char *, char *);
92 static int tty_is_devpts(const char *);
93 static struct passwd *get_authpw(void);
96 * Returns TRUE if the user successfully authenticates, else FALSE.
99 check_user(int validated, int mode)
101 char *timestampdir = NULL;
102 char *timestampfile = NULL;
105 int status, rval = TRUE;
107 /* Stash the tty's ctime for tty ticket comparison. */
108 if (def_tty_tickets && user_ttypath && stat(user_ttypath, &sb) == 0) {
109 tty_info.dev = sb.st_dev;
110 tty_info.ino = sb.st_ino;
111 tty_info.rdev = sb.st_rdev;
112 if (tty_is_devpts(user_ttypath))
113 ctim_get(&sb, &tty_info.ctime);
116 /* Always prompt for a password when -k was specified with the command. */
117 if (ISSET(mode, MODE_IGNORE_TICKET)) {
118 SET(validated, FLAG_CHECK_USER);
121 * Don't prompt for the root passwd or if the user is exempt.
122 * If the user is not changing uid/gid, no need for a password.
124 if (user_uid == 0 || (user_uid == runas_pw->pw_uid &&
125 (!runas_gr || user_in_group(sudo_user.pw, runas_gr->gr_name))) ||
130 if (build_timestamp(×tampdir, ×tampfile) == -1)
133 status = timestamp_status(timestampdir, timestampfile, user_name,
136 if (status != TS_CURRENT || ISSET(validated, FLAG_CHECK_USER)) {
137 struct passwd *auth_pw;
139 /* Bail out if we are non-interactive and a password is required */
140 if (ISSET(mode, MODE_NONINTERACTIVE)) {
141 warningx(_("sorry, a password is required to run %s"), getprogname());
145 /* XXX - should not lecture if askpass helper is being used. */
148 /* Expand any escapes in the prompt. */
149 prompt = expand_prompt(user_prompt ? user_prompt : def_passprompt,
150 user_name, user_shost);
152 auth_pw = get_authpw();
153 rval = verify_user(auth_pw, prompt);
156 /* Only update timestamp if user was validated. */
157 if (rval == TRUE && ISSET(validated, VALIDATE_OK) &&
158 !ISSET(mode, MODE_IGNORE_TICKET) && status != TS_ERROR)
159 update_timestamp(timestampdir, timestampfile);
161 efree(timestampfile);
166 #define DEFAULT_LECTURE "\n" \
167 "We trust you have received the usual lecture from the local System\n" \
168 "Administrator. It usually boils down to these three things:\n\n" \
169 " #1) Respect the privacy of others.\n" \
170 " #2) Think before you type.\n" \
171 " #3) With great power comes great responsibility.\n\n"
174 * Standard sudo lecture.
182 struct sudo_conv_message msg;
183 struct sudo_conv_reply repl;
185 if (def_lecture == never ||
186 (def_lecture == once && status != TS_MISSING && status != TS_ERROR))
189 memset(&msg, 0, sizeof(msg));
190 memset(&repl, 0, sizeof(repl));
192 if (def_lecture_file && (fp = fopen(def_lecture_file, "r")) != NULL) {
193 while ((nread = fread(buf, sizeof(char), sizeof(buf) - 1, fp)) != 0) {
194 buf[sizeof(buf) - 1] = '\0';
195 msg.msg_type = SUDO_CONV_ERROR_MSG;
197 sudo_conv(1, &msg, &repl);
201 msg.msg_type = SUDO_CONV_ERROR_MSG;
202 msg.msg = _(DEFAULT_LECTURE);
203 sudo_conv(1, &msg, &repl);
208 * Update the time on the timestamp file/dir or create it if necessary.
211 update_timestamp(char *timestampdir, char *timestampfile)
213 /* If using tty timestamps but we have no tty there is nothing to do. */
214 if (def_tty_tickets && !user_ttypath)
217 if (timestamp_uid != 0)
218 set_perms(PERM_TIMESTAMP);
221 * Store tty info in timestamp file
223 int fd = open(timestampfile, O_WRONLY|O_CREAT, 0600);
225 log_error(NO_EXIT|USE_ERRNO, _("unable to open %s"), timestampfile);
227 lock_file(fd, SUDO_LOCK);
228 if (write(fd, &tty_info, sizeof(tty_info)) != sizeof(tty_info)) {
229 log_error(NO_EXIT|USE_ERRNO, _("unable to write to %s"),
235 if (touch(-1, timestampdir, NULL) == -1) {
236 if (mkdir(timestampdir, 0700) == -1) {
237 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"),
242 if (timestamp_uid != 0)
247 * Expand %h and %u escapes in the prompt and pass back the dynamically
248 * allocated result. Returns the same string if there are no escapes.
251 expand_prompt(char *old_prompt, char *user, char *host)
255 char *p, *np, *new_prompt, *endp;
257 /* How much space do we need to malloc for the prompt? */
259 for (p = old_prompt, len = strlen(old_prompt); *p; p++) {
264 len += strlen(user_shost) - 2;
269 len += strlen(user_host) - 2;
276 else if (def_targetpw || def_runaspw)
277 len += strlen(runas_pw->pw_name) - 2;
279 len += strlen(user_name) - 2;
284 len += strlen(user_name) - 2;
289 len += strlen(runas_pw->pw_name) - 2;
304 new_prompt = emalloc(++len);
305 endp = new_prompt + len;
306 for (p = old_prompt, np = new_prompt; *p; p++) {
311 n = strlcpy(np, user_shost, np - endp);
318 n = strlcpy(np, user_host, np - endp);
326 n = strlcpy(np, "root", np - endp);
327 else if (def_targetpw || def_runaspw)
328 n = strlcpy(np, runas_pw->pw_name, np - endp);
330 n = strlcpy(np, user_name, np - endp);
337 n = strlcpy(np, user_name, np - endp);
344 n = strlcpy(np, runas_pw->pw_name, np - endp);
350 /* convert %% -> % */
364 new_prompt = old_prompt;
369 /* We pre-allocate enough space, so this should never happen. */
370 errorx(1, _("internal error, expand_prompt() overflow"));
374 * Checks if the user is exempt from supplying a password.
379 if (!def_exempt_group)
381 return user_in_group(sudo_user.pw, def_exempt_group);
385 * Fills in timestampdir as well as timestampfile if using tty tickets.
388 build_timestamp(char **timestampdir, char **timestampfile)
393 dirparent = def_timestampdir;
394 len = easprintf(timestampdir, "%s/%s", dirparent, user_name);
399 * Timestamp file may be a file in the directory or NUL to use
400 * the directory as the timestamp.
402 if (def_tty_tickets) {
405 if ((p = strrchr(user_tty, '/')))
410 len = easprintf(timestampfile, "%s/%s/%s:%s", dirparent, user_name,
411 p, runas_pw->pw_name);
413 len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name, p);
416 } else if (def_targetpw) {
417 len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name,
422 *timestampfile = NULL;
426 log_error(0, _("timestamp path too long: %s"), *timestampfile);
431 * Check the timestamp file and directory and return their status.
434 timestamp_status(char *timestampdir, char *timestampfile, char *user, int flags)
437 struct timeval boottime, mtime;
439 char *dirparent = def_timestampdir;
440 int status = TS_ERROR; /* assume the worst */
442 if (timestamp_uid != 0)
443 set_perms(PERM_TIMESTAMP);
446 * Sanity check dirparent and make it if it doesn't already exist.
447 * We start out assuming the worst (that the dir is not sane) and
448 * if it is ok upgrade the status to ``no timestamp file''.
449 * Note that we don't check the parent(s) of dirparent for
450 * sanity since the sudo dir is often just located in /tmp.
452 if (lstat(dirparent, &sb) == 0) {
453 if (!S_ISDIR(sb.st_mode))
454 log_error(NO_EXIT, _("%s exists but is not a directory (0%o)"),
455 dirparent, (unsigned int) sb.st_mode);
456 else if (sb.st_uid != timestamp_uid)
457 log_error(NO_EXIT, _("%s owned by uid %u, should be uid %u"),
458 dirparent, (unsigned int) sb.st_uid,
459 (unsigned int) timestamp_uid);
460 else if ((sb.st_mode & 0000022))
462 _("%s writable by non-owner (0%o), should be mode 0700"),
463 dirparent, (unsigned int) sb.st_mode);
465 if ((sb.st_mode & 0000777) != 0700)
466 (void) chmod(dirparent, 0700);
469 } else if (errno != ENOENT) {
470 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), dirparent);
472 /* No dirparent, try to make one. */
473 if (ISSET(flags, TS_MAKE_DIRS)) {
474 if (mkdir(dirparent, S_IRWXU))
475 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"),
481 if (status == TS_ERROR)
485 * Sanity check the user's ticket dir. We start by downgrading
486 * the status to TS_ERROR. If the ticket dir exists and is sane
487 * this will be upgraded to TS_OLD. If the dir does not exist,
488 * it will be upgraded to TS_MISSING.
490 status = TS_ERROR; /* downgrade status again */
491 if (lstat(timestampdir, &sb) == 0) {
492 if (!S_ISDIR(sb.st_mode)) {
493 if (S_ISREG(sb.st_mode)) {
494 /* convert from old style */
495 if (unlink(timestampdir) == 0)
498 log_error(NO_EXIT, _("%s exists but is not a directory (0%o)"),
499 timestampdir, (unsigned int) sb.st_mode);
500 } else if (sb.st_uid != timestamp_uid)
501 log_error(NO_EXIT, _("%s owned by uid %u, should be uid %u"),
502 timestampdir, (unsigned int) sb.st_uid,
503 (unsigned int) timestamp_uid);
504 else if ((sb.st_mode & 0000022))
506 _("%s writable by non-owner (0%o), should be mode 0700"),
507 timestampdir, (unsigned int) sb.st_mode);
509 if ((sb.st_mode & 0000777) != 0700)
510 (void) chmod(timestampdir, 0700);
511 status = TS_OLD; /* do date check later */
513 } else if (errno != ENOENT) {
514 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), timestampdir);
519 * If there is no user ticket dir, AND we are in tty ticket mode,
520 * AND the TS_MAKE_DIRS flag is set, create the user ticket dir.
522 if (status == TS_MISSING && timestampfile && ISSET(flags, TS_MAKE_DIRS)) {
523 if (mkdir(timestampdir, S_IRWXU) == -1) {
525 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"), timestampdir);
530 * Sanity check the tty ticket file if it exists.
532 if (timestampfile && status != TS_ERROR) {
533 if (status != TS_MISSING)
534 status = TS_NOFILE; /* dir there, file missing */
535 if (def_tty_tickets && !user_ttypath)
536 goto done; /* no tty, always prompt */
537 if (lstat(timestampfile, &sb) == 0) {
538 if (!S_ISREG(sb.st_mode)) {
540 log_error(NO_EXIT, _("%s exists but is not a regular file (0%o)"),
541 timestampfile, (unsigned int) sb.st_mode);
543 /* If bad uid or file mode, complain and kill the bogus file. */
544 if (sb.st_uid != timestamp_uid) {
546 _("%s owned by uid %u, should be uid %u"),
547 timestampfile, (unsigned int) sb.st_uid,
548 (unsigned int) timestamp_uid);
549 (void) unlink(timestampfile);
550 } else if ((sb.st_mode & 0000022)) {
552 _("%s writable by non-owner (0%o), should be mode 0600"),
553 timestampfile, (unsigned int) sb.st_mode);
554 (void) unlink(timestampfile);
556 /* If not mode 0600, fix it. */
557 if ((sb.st_mode & 0000777) != 0600)
558 (void) chmod(timestampfile, 0600);
561 * Check for stored tty info. If the file is zero-sized
562 * it is an old-style timestamp with no tty info in it.
563 * If removing, we don't care about the contents.
564 * The actual mtime check is done later.
566 if (ISSET(flags, TS_REMOVE)) {
568 } else if (sb.st_size != 0) {
569 struct tty_info info;
570 int fd = open(timestampfile, O_RDONLY, 0644);
572 if (read(fd, &info, sizeof(info)) == sizeof(info) &&
573 memcmp(&info, &tty_info, sizeof(info)) == 0) {
581 } else if (errno != ENOENT) {
582 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), timestampfile);
588 * If the file/dir exists and we are not removing it, check its mtime.
590 if (status == TS_OLD && !ISSET(flags, TS_REMOVE)) {
591 mtim_get(&sb, &mtime);
592 /* Negative timeouts only expire manually (sudo -k). */
593 if (def_timestamp_timeout < 0 && mtime.tv_sec != 0)
597 if (def_timestamp_timeout &&
598 now - mtime.tv_sec < 60 * def_timestamp_timeout) {
600 * Check for bogus time on the stampfile. The clock may
601 * have been set back or someone could be trying to spoof us.
603 if (mtime.tv_sec > now + 60 * def_timestamp_timeout * 2) {
604 time_t tv_sec = (time_t)mtime.tv_sec;
606 _("timestamp too far in the future: %20.20s"),
609 (void) unlink(timestampfile);
611 (void) rmdir(timestampdir);
613 } else if (get_boottime(&boottime) && timevalcmp(&mtime, &boottime, <)) {
623 if (timestamp_uid != 0)
629 * Remove the timestamp ticket file/dir.
632 remove_timestamp(int remove)
635 char *timestampdir, *timestampfile, *path;
638 if (build_timestamp(×tampdir, ×tampfile) == -1)
641 status = timestamp_status(timestampdir, timestampfile, user_name,
643 if (status != TS_MISSING && status != TS_ERROR) {
644 path = timestampfile ? timestampfile : timestampdir;
647 status = unlink(timestampfile);
649 status = rmdir(timestampdir);
650 if (status == -1 && errno != ENOENT) {
652 _("unable to remove %s (%s), will reset to the epoch"),
653 path, strerror(errno));
659 if (touch(-1, path, &tv) == -1 && errno != ENOENT)
660 error(1, _("unable to reset %s to the epoch"), path);
665 efree(timestampfile);
669 * Returns TRUE if tty lives on a devpts or /devices filesystem, else FALSE.
670 * Unlike most filesystems, the ctime of devpts nodes is not updated when
671 * the device node is written to, only when the inode's status changes,
672 * typically via the chmod, chown, link, rename, or utimes system calls.
673 * Since the ctime is "stable" in this case, we can stash it the tty ticket
674 * file and use it to determine whether the tty ticket file is stale.
677 tty_is_devpts(const char *tty)
683 #ifndef DEVPTS_SUPER_MAGIC
684 # define DEVPTS_SUPER_MAGIC 0x1cd1
687 if (statfs(tty, &sfs) == 0) {
688 if (sfs.f_type == DEVPTS_SUPER_MAGIC)
691 #elif defined(__sun) && defined(__SVR4)
694 if (statvfs(tty, &sfs) == 0) {
695 if (strcmp(sfs.f_fstr, "devices") == 0)
698 #endif /* __linux__ */
703 * Get passwd entry for the user we are going to authenticate as.
704 * By default, this is the user invoking sudo. In the most common
705 * case, this matches sudo_user.pw or runas_pw.
707 static struct passwd *
713 if ((pw = sudo_getpwuid(ROOT_UID)) == NULL)
714 log_error(0, _("unknown uid: %u"), ROOT_UID);
715 } else if (def_runaspw) {
716 if ((pw = sudo_getpwnam(def_runas_default)) == NULL)
717 log_error(0, _("unknown user: %s"), def_runas_default);
718 } else if (def_targetpw) {
719 if (runas_pw->pw_name == NULL)
720 log_error(NO_MAIL|MSG_ONLY, _("unknown uid: %u"),
721 (unsigned int) runas_pw->pw_uid);
725 pw_addref(sudo_user.pw);