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 struct passwd *auth_pw;
102 char *timestampdir = NULL;
103 char *timestampfile = NULL;
106 int status, rval = TRUE;
107 int need_pass = def_authenticate;
110 * Init authentication system regardless of whether we need a password.
111 * Required for proper PAM session support.
113 auth_pw = get_authpw();
114 if (sudo_auth_init(auth_pw) == -1) {
120 /* Always need a password when -k was specified with the command. */
121 if (ISSET(mode, MODE_IGNORE_TICKET)) {
122 SET(validated, FLAG_CHECK_USER);
125 * Don't prompt for the root passwd or if the user is exempt.
126 * If the user is not changing uid/gid, no need for a password.
128 if (user_uid == 0 || (user_uid == runas_pw->pw_uid &&
129 (!runas_gr || user_in_group(sudo_user.pw, runas_gr->gr_name)))
137 /* Stash the tty's ctime for tty ticket comparison. */
138 if (def_tty_tickets && user_ttypath && stat(user_ttypath, &sb) == 0) {
139 tty_info.dev = sb.st_dev;
140 tty_info.ino = sb.st_ino;
141 tty_info.rdev = sb.st_rdev;
142 if (tty_is_devpts(user_ttypath))
143 ctim_get(&sb, &tty_info.ctime);
146 if (build_timestamp(×tampdir, ×tampfile) == -1) {
151 status = timestamp_status(timestampdir, timestampfile, user_name,
154 if (status != TS_CURRENT || ISSET(validated, FLAG_CHECK_USER)) {
155 /* Bail out if we are non-interactive and a password is required */
156 if (ISSET(mode, MODE_NONINTERACTIVE)) {
157 warningx(_("sorry, a password is required to run %s"), getprogname());
162 /* XXX - should not lecture if askpass helper is being used. */
165 /* Expand any escapes in the prompt. */
166 prompt = expand_prompt(user_prompt ? user_prompt : def_passprompt,
167 user_name, user_shost);
169 rval = verify_user(auth_pw, prompt);
171 /* Only update timestamp if user was validated. */
172 if (rval == TRUE && ISSET(validated, VALIDATE_OK) &&
173 !ISSET(mode, MODE_IGNORE_TICKET) && status != TS_ERROR)
174 update_timestamp(timestampdir, timestampfile);
176 efree(timestampfile);
179 sudo_auth_cleanup(auth_pw);
185 #define DEFAULT_LECTURE "\n" \
186 "We trust you have received the usual lecture from the local System\n" \
187 "Administrator. It usually boils down to these three things:\n\n" \
188 " #1) Respect the privacy of others.\n" \
189 " #2) Think before you type.\n" \
190 " #3) With great power comes great responsibility.\n\n"
193 * Standard sudo lecture.
201 struct sudo_conv_message msg;
202 struct sudo_conv_reply repl;
204 if (def_lecture == never ||
205 (def_lecture == once && status != TS_MISSING && status != TS_ERROR))
208 memset(&msg, 0, sizeof(msg));
209 memset(&repl, 0, sizeof(repl));
211 if (def_lecture_file && (fp = fopen(def_lecture_file, "r")) != NULL) {
212 while ((nread = fread(buf, sizeof(char), sizeof(buf) - 1, fp)) != 0) {
213 buf[sizeof(buf) - 1] = '\0';
214 msg.msg_type = SUDO_CONV_ERROR_MSG;
216 sudo_conv(1, &msg, &repl);
220 msg.msg_type = SUDO_CONV_ERROR_MSG;
221 msg.msg = _(DEFAULT_LECTURE);
222 sudo_conv(1, &msg, &repl);
227 * Update the time on the timestamp file/dir or create it if necessary.
230 update_timestamp(char *timestampdir, char *timestampfile)
232 /* If using tty timestamps but we have no tty there is nothing to do. */
233 if (def_tty_tickets && !user_ttypath)
236 if (timestamp_uid != 0)
237 set_perms(PERM_TIMESTAMP);
240 * Store tty info in timestamp file
242 int fd = open(timestampfile, O_WRONLY|O_CREAT, 0600);
244 log_error(NO_EXIT|USE_ERRNO, _("unable to open %s"), timestampfile);
246 lock_file(fd, SUDO_LOCK);
247 if (write(fd, &tty_info, sizeof(tty_info)) != sizeof(tty_info)) {
248 log_error(NO_EXIT|USE_ERRNO, _("unable to write to %s"),
254 if (touch(-1, timestampdir, NULL) == -1) {
255 if (mkdir(timestampdir, 0700) == -1) {
256 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"),
261 if (timestamp_uid != 0)
266 * Expand %h and %u escapes in the prompt and pass back the dynamically
267 * allocated result. Returns the same string if there are no escapes.
270 expand_prompt(char *old_prompt, char *user, char *host)
274 char *p, *np, *new_prompt, *endp;
276 /* How much space do we need to malloc for the prompt? */
278 for (p = old_prompt, len = strlen(old_prompt); *p; p++) {
283 len += strlen(user_shost) - 2;
288 len += strlen(user_host) - 2;
295 else if (def_targetpw || def_runaspw)
296 len += strlen(runas_pw->pw_name) - 2;
298 len += strlen(user_name) - 2;
303 len += strlen(user_name) - 2;
308 len += strlen(runas_pw->pw_name) - 2;
323 new_prompt = emalloc(++len);
324 endp = new_prompt + len;
325 for (p = old_prompt, np = new_prompt; *p; p++) {
330 n = strlcpy(np, user_shost, np - endp);
337 n = strlcpy(np, user_host, np - endp);
345 n = strlcpy(np, "root", np - endp);
346 else if (def_targetpw || def_runaspw)
347 n = strlcpy(np, runas_pw->pw_name, np - endp);
349 n = strlcpy(np, user_name, np - endp);
356 n = strlcpy(np, user_name, np - endp);
363 n = strlcpy(np, runas_pw->pw_name, np - endp);
369 /* convert %% -> % */
383 new_prompt = old_prompt;
388 /* We pre-allocate enough space, so this should never happen. */
389 errorx(1, _("internal error, expand_prompt() overflow"));
393 * Checks if the user is exempt from supplying a password.
398 if (!def_exempt_group)
400 return user_in_group(sudo_user.pw, def_exempt_group);
404 * Fills in timestampdir as well as timestampfile if using tty tickets.
407 build_timestamp(char **timestampdir, char **timestampfile)
412 dirparent = def_timestampdir;
413 len = easprintf(timestampdir, "%s/%s", dirparent, user_name);
418 * Timestamp file may be a file in the directory or NUL to use
419 * the directory as the timestamp.
421 if (def_tty_tickets) {
424 if ((p = strrchr(user_tty, '/')))
429 len = easprintf(timestampfile, "%s/%s/%s:%s", dirparent, user_name,
430 p, runas_pw->pw_name);
432 len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name, p);
435 } else if (def_targetpw) {
436 len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name,
441 *timestampfile = NULL;
445 log_error(0, _("timestamp path too long: %s"), *timestampfile);
450 * Check the timestamp file and directory and return their status.
453 timestamp_status(char *timestampdir, char *timestampfile, char *user, int flags)
456 struct timeval boottime, mtime;
458 char *dirparent = def_timestampdir;
459 int status = TS_ERROR; /* assume the worst */
461 if (timestamp_uid != 0)
462 set_perms(PERM_TIMESTAMP);
465 * Sanity check dirparent and make it if it doesn't already exist.
466 * We start out assuming the worst (that the dir is not sane) and
467 * if it is ok upgrade the status to ``no timestamp file''.
468 * Note that we don't check the parent(s) of dirparent for
469 * sanity since the sudo dir is often just located in /tmp.
471 if (lstat(dirparent, &sb) == 0) {
472 if (!S_ISDIR(sb.st_mode))
473 log_error(NO_EXIT, _("%s exists but is not a directory (0%o)"),
474 dirparent, (unsigned int) sb.st_mode);
475 else if (sb.st_uid != timestamp_uid)
476 log_error(NO_EXIT, _("%s owned by uid %u, should be uid %u"),
477 dirparent, (unsigned int) sb.st_uid,
478 (unsigned int) timestamp_uid);
479 else if ((sb.st_mode & 0000022))
481 _("%s writable by non-owner (0%o), should be mode 0700"),
482 dirparent, (unsigned int) sb.st_mode);
484 if ((sb.st_mode & 0000777) != 0700)
485 (void) chmod(dirparent, 0700);
488 } else if (errno != ENOENT) {
489 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), dirparent);
491 /* No dirparent, try to make one. */
492 if (ISSET(flags, TS_MAKE_DIRS)) {
493 if (mkdir(dirparent, S_IRWXU))
494 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"),
500 if (status == TS_ERROR)
504 * Sanity check the user's ticket dir. We start by downgrading
505 * the status to TS_ERROR. If the ticket dir exists and is sane
506 * this will be upgraded to TS_OLD. If the dir does not exist,
507 * it will be upgraded to TS_MISSING.
509 status = TS_ERROR; /* downgrade status again */
510 if (lstat(timestampdir, &sb) == 0) {
511 if (!S_ISDIR(sb.st_mode)) {
512 if (S_ISREG(sb.st_mode)) {
513 /* convert from old style */
514 if (unlink(timestampdir) == 0)
517 log_error(NO_EXIT, _("%s exists but is not a directory (0%o)"),
518 timestampdir, (unsigned int) sb.st_mode);
519 } else if (sb.st_uid != timestamp_uid)
520 log_error(NO_EXIT, _("%s owned by uid %u, should be uid %u"),
521 timestampdir, (unsigned int) sb.st_uid,
522 (unsigned int) timestamp_uid);
523 else if ((sb.st_mode & 0000022))
525 _("%s writable by non-owner (0%o), should be mode 0700"),
526 timestampdir, (unsigned int) sb.st_mode);
528 if ((sb.st_mode & 0000777) != 0700)
529 (void) chmod(timestampdir, 0700);
530 status = TS_OLD; /* do date check later */
532 } else if (errno != ENOENT) {
533 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), timestampdir);
538 * If there is no user ticket dir, AND we are in tty ticket mode,
539 * AND the TS_MAKE_DIRS flag is set, create the user ticket dir.
541 if (status == TS_MISSING && timestampfile && ISSET(flags, TS_MAKE_DIRS)) {
542 if (mkdir(timestampdir, S_IRWXU) == -1) {
544 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"), timestampdir);
549 * Sanity check the tty ticket file if it exists.
551 if (timestampfile && status != TS_ERROR) {
552 if (status != TS_MISSING)
553 status = TS_NOFILE; /* dir there, file missing */
554 if (def_tty_tickets && !user_ttypath)
555 goto done; /* no tty, always prompt */
556 if (lstat(timestampfile, &sb) == 0) {
557 if (!S_ISREG(sb.st_mode)) {
559 log_error(NO_EXIT, _("%s exists but is not a regular file (0%o)"),
560 timestampfile, (unsigned int) sb.st_mode);
562 /* If bad uid or file mode, complain and kill the bogus file. */
563 if (sb.st_uid != timestamp_uid) {
565 _("%s owned by uid %u, should be uid %u"),
566 timestampfile, (unsigned int) sb.st_uid,
567 (unsigned int) timestamp_uid);
568 (void) unlink(timestampfile);
569 } else if ((sb.st_mode & 0000022)) {
571 _("%s writable by non-owner (0%o), should be mode 0600"),
572 timestampfile, (unsigned int) sb.st_mode);
573 (void) unlink(timestampfile);
575 /* If not mode 0600, fix it. */
576 if ((sb.st_mode & 0000777) != 0600)
577 (void) chmod(timestampfile, 0600);
580 * Check for stored tty info. If the file is zero-sized
581 * it is an old-style timestamp with no tty info in it.
582 * If removing, we don't care about the contents.
583 * The actual mtime check is done later.
585 if (ISSET(flags, TS_REMOVE)) {
587 } else if (sb.st_size != 0) {
588 struct tty_info info;
589 int fd = open(timestampfile, O_RDONLY, 0644);
591 if (read(fd, &info, sizeof(info)) == sizeof(info) &&
592 memcmp(&info, &tty_info, sizeof(info)) == 0) {
600 } else if (errno != ENOENT) {
601 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), timestampfile);
607 * If the file/dir exists and we are not removing it, check its mtime.
609 if (status == TS_OLD && !ISSET(flags, TS_REMOVE)) {
610 mtim_get(&sb, &mtime);
611 /* Negative timeouts only expire manually (sudo -k). */
612 if (def_timestamp_timeout < 0 && mtime.tv_sec != 0)
616 if (def_timestamp_timeout &&
617 now - mtime.tv_sec < 60 * def_timestamp_timeout) {
619 * Check for bogus time on the stampfile. The clock may
620 * have been set back or someone could be trying to spoof us.
622 if (mtime.tv_sec > now + 60 * def_timestamp_timeout * 2) {
623 time_t tv_sec = (time_t)mtime.tv_sec;
625 _("timestamp too far in the future: %20.20s"),
628 (void) unlink(timestampfile);
630 (void) rmdir(timestampdir);
632 } else if (get_boottime(&boottime) && timevalcmp(&mtime, &boottime, <)) {
642 if (timestamp_uid != 0)
648 * Remove the timestamp ticket file/dir.
651 remove_timestamp(int remove)
654 char *timestampdir, *timestampfile, *path;
657 if (build_timestamp(×tampdir, ×tampfile) == -1)
660 status = timestamp_status(timestampdir, timestampfile, user_name,
662 if (status != TS_MISSING && status != TS_ERROR) {
663 path = timestampfile ? timestampfile : timestampdir;
666 status = unlink(timestampfile);
668 status = rmdir(timestampdir);
669 if (status == -1 && errno != ENOENT) {
671 _("unable to remove %s (%s), will reset to the epoch"),
672 path, strerror(errno));
678 if (touch(-1, path, &tv) == -1 && errno != ENOENT)
679 error(1, _("unable to reset %s to the epoch"), path);
684 efree(timestampfile);
688 * Returns TRUE if tty lives on a devpts or /devices filesystem, else FALSE.
689 * Unlike most filesystems, the ctime of devpts nodes is not updated when
690 * the device node is written to, only when the inode's status changes,
691 * typically via the chmod, chown, link, rename, or utimes system calls.
692 * Since the ctime is "stable" in this case, we can stash it the tty ticket
693 * file and use it to determine whether the tty ticket file is stale.
696 tty_is_devpts(const char *tty)
702 #ifndef DEVPTS_SUPER_MAGIC
703 # define DEVPTS_SUPER_MAGIC 0x1cd1
706 if (statfs(tty, &sfs) == 0) {
707 if (sfs.f_type == DEVPTS_SUPER_MAGIC)
710 #elif defined(__sun) && defined(__SVR4)
713 if (statvfs(tty, &sfs) == 0) {
714 if (strcmp(sfs.f_fstr, "devices") == 0)
717 #endif /* __linux__ */
722 * Get passwd entry for the user we are going to authenticate as.
723 * By default, this is the user invoking sudo. In the most common
724 * case, this matches sudo_user.pw or runas_pw.
726 static struct passwd *
732 if ((pw = sudo_getpwuid(ROOT_UID)) == NULL)
733 log_error(0, _("unknown uid: %u"), ROOT_UID);
734 } else if (def_runaspw) {
735 if ((pw = sudo_getpwnam(def_runas_default)) == NULL)
736 log_error(0, _("unknown user: %s"), def_runas_default);
737 } else if (def_targetpw) {
738 if (runas_pw->pw_name == NULL)
739 log_error(NO_MAIL|MSG_ONLY, _("unknown uid: %u"),
740 (unsigned int) runas_pw->pw_uid);
744 pw_addref(sudo_user.pw);