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;
108 /* Stash the tty's ctime for tty ticket comparison. */
109 if (def_tty_tickets && user_ttypath && stat(user_ttypath, &sb) == 0) {
110 tty_info.dev = sb.st_dev;
111 tty_info.ino = sb.st_ino;
112 tty_info.rdev = sb.st_rdev;
113 if (tty_is_devpts(user_ttypath))
114 ctim_get(&sb, &tty_info.ctime);
117 /* Init authentication system regardless of whether we need a password. */
118 auth_pw = get_authpw();
119 if (sudo_auth_init(auth_pw) == -1) {
124 /* Always prompt for a password when -k was specified with the command. */
125 if (ISSET(mode, MODE_IGNORE_TICKET)) {
126 SET(validated, FLAG_CHECK_USER);
129 * Don't prompt for the root passwd or if the user is exempt.
130 * If the user is not changing uid/gid, no need for a password.
132 if (user_uid == 0 || (user_uid == runas_pw->pw_uid &&
133 (!runas_gr || user_in_group(sudo_user.pw, runas_gr->gr_name))) ||
138 if (build_timestamp(×tampdir, ×tampfile) == -1) {
143 status = timestamp_status(timestampdir, timestampfile, user_name,
146 if (status != TS_CURRENT || ISSET(validated, FLAG_CHECK_USER)) {
147 /* Bail out if we are non-interactive and a password is required */
148 if (ISSET(mode, MODE_NONINTERACTIVE)) {
149 warningx(_("sorry, a password is required to run %s"), getprogname());
154 /* XXX - should not lecture if askpass helper is being used. */
157 /* Expand any escapes in the prompt. */
158 prompt = expand_prompt(user_prompt ? user_prompt : def_passprompt,
159 user_name, user_shost);
161 rval = verify_user(auth_pw, prompt);
163 /* Only update timestamp if user was validated. */
164 if (rval == TRUE && ISSET(validated, VALIDATE_OK) &&
165 !ISSET(mode, MODE_IGNORE_TICKET) && status != TS_ERROR)
166 update_timestamp(timestampdir, timestampfile);
168 efree(timestampfile);
171 sudo_auth_cleanup(auth_pw);
177 #define DEFAULT_LECTURE "\n" \
178 "We trust you have received the usual lecture from the local System\n" \
179 "Administrator. It usually boils down to these three things:\n\n" \
180 " #1) Respect the privacy of others.\n" \
181 " #2) Think before you type.\n" \
182 " #3) With great power comes great responsibility.\n\n"
185 * Standard sudo lecture.
193 struct sudo_conv_message msg;
194 struct sudo_conv_reply repl;
196 if (def_lecture == never ||
197 (def_lecture == once && status != TS_MISSING && status != TS_ERROR))
200 memset(&msg, 0, sizeof(msg));
201 memset(&repl, 0, sizeof(repl));
203 if (def_lecture_file && (fp = fopen(def_lecture_file, "r")) != NULL) {
204 while ((nread = fread(buf, sizeof(char), sizeof(buf) - 1, fp)) != 0) {
205 buf[sizeof(buf) - 1] = '\0';
206 msg.msg_type = SUDO_CONV_ERROR_MSG;
208 sudo_conv(1, &msg, &repl);
212 msg.msg_type = SUDO_CONV_ERROR_MSG;
213 msg.msg = _(DEFAULT_LECTURE);
214 sudo_conv(1, &msg, &repl);
219 * Update the time on the timestamp file/dir or create it if necessary.
222 update_timestamp(char *timestampdir, char *timestampfile)
224 /* If using tty timestamps but we have no tty there is nothing to do. */
225 if (def_tty_tickets && !user_ttypath)
228 if (timestamp_uid != 0)
229 set_perms(PERM_TIMESTAMP);
232 * Store tty info in timestamp file
234 int fd = open(timestampfile, O_WRONLY|O_CREAT, 0600);
236 log_error(NO_EXIT|USE_ERRNO, _("unable to open %s"), timestampfile);
238 lock_file(fd, SUDO_LOCK);
239 if (write(fd, &tty_info, sizeof(tty_info)) != sizeof(tty_info)) {
240 log_error(NO_EXIT|USE_ERRNO, _("unable to write to %s"),
246 if (touch(-1, timestampdir, NULL) == -1) {
247 if (mkdir(timestampdir, 0700) == -1) {
248 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"),
253 if (timestamp_uid != 0)
258 * Expand %h and %u escapes in the prompt and pass back the dynamically
259 * allocated result. Returns the same string if there are no escapes.
262 expand_prompt(char *old_prompt, char *user, char *host)
266 char *p, *np, *new_prompt, *endp;
268 /* How much space do we need to malloc for the prompt? */
270 for (p = old_prompt, len = strlen(old_prompt); *p; p++) {
275 len += strlen(user_shost) - 2;
280 len += strlen(user_host) - 2;
287 else if (def_targetpw || def_runaspw)
288 len += strlen(runas_pw->pw_name) - 2;
290 len += strlen(user_name) - 2;
295 len += strlen(user_name) - 2;
300 len += strlen(runas_pw->pw_name) - 2;
315 new_prompt = emalloc(++len);
316 endp = new_prompt + len;
317 for (p = old_prompt, np = new_prompt; *p; p++) {
322 n = strlcpy(np, user_shost, np - endp);
329 n = strlcpy(np, user_host, np - endp);
337 n = strlcpy(np, "root", np - endp);
338 else if (def_targetpw || def_runaspw)
339 n = strlcpy(np, runas_pw->pw_name, np - endp);
341 n = strlcpy(np, user_name, np - endp);
348 n = strlcpy(np, user_name, np - endp);
355 n = strlcpy(np, runas_pw->pw_name, np - endp);
361 /* convert %% -> % */
375 new_prompt = old_prompt;
380 /* We pre-allocate enough space, so this should never happen. */
381 errorx(1, _("internal error, expand_prompt() overflow"));
385 * Checks if the user is exempt from supplying a password.
390 if (!def_exempt_group)
392 return user_in_group(sudo_user.pw, def_exempt_group);
396 * Fills in timestampdir as well as timestampfile if using tty tickets.
399 build_timestamp(char **timestampdir, char **timestampfile)
404 dirparent = def_timestampdir;
405 len = easprintf(timestampdir, "%s/%s", dirparent, user_name);
410 * Timestamp file may be a file in the directory or NUL to use
411 * the directory as the timestamp.
413 if (def_tty_tickets) {
416 if ((p = strrchr(user_tty, '/')))
421 len = easprintf(timestampfile, "%s/%s/%s:%s", dirparent, user_name,
422 p, runas_pw->pw_name);
424 len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name, p);
427 } else if (def_targetpw) {
428 len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name,
433 *timestampfile = NULL;
437 log_error(0, _("timestamp path too long: %s"), *timestampfile);
442 * Check the timestamp file and directory and return their status.
445 timestamp_status(char *timestampdir, char *timestampfile, char *user, int flags)
448 struct timeval boottime, mtime;
450 char *dirparent = def_timestampdir;
451 int status = TS_ERROR; /* assume the worst */
453 if (timestamp_uid != 0)
454 set_perms(PERM_TIMESTAMP);
457 * Sanity check dirparent and make it if it doesn't already exist.
458 * We start out assuming the worst (that the dir is not sane) and
459 * if it is ok upgrade the status to ``no timestamp file''.
460 * Note that we don't check the parent(s) of dirparent for
461 * sanity since the sudo dir is often just located in /tmp.
463 if (lstat(dirparent, &sb) == 0) {
464 if (!S_ISDIR(sb.st_mode))
465 log_error(NO_EXIT, _("%s exists but is not a directory (0%o)"),
466 dirparent, (unsigned int) sb.st_mode);
467 else if (sb.st_uid != timestamp_uid)
468 log_error(NO_EXIT, _("%s owned by uid %u, should be uid %u"),
469 dirparent, (unsigned int) sb.st_uid,
470 (unsigned int) timestamp_uid);
471 else if ((sb.st_mode & 0000022))
473 _("%s writable by non-owner (0%o), should be mode 0700"),
474 dirparent, (unsigned int) sb.st_mode);
476 if ((sb.st_mode & 0000777) != 0700)
477 (void) chmod(dirparent, 0700);
480 } else if (errno != ENOENT) {
481 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), dirparent);
483 /* No dirparent, try to make one. */
484 if (ISSET(flags, TS_MAKE_DIRS)) {
485 if (mkdir(dirparent, S_IRWXU))
486 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"),
492 if (status == TS_ERROR)
496 * Sanity check the user's ticket dir. We start by downgrading
497 * the status to TS_ERROR. If the ticket dir exists and is sane
498 * this will be upgraded to TS_OLD. If the dir does not exist,
499 * it will be upgraded to TS_MISSING.
501 status = TS_ERROR; /* downgrade status again */
502 if (lstat(timestampdir, &sb) == 0) {
503 if (!S_ISDIR(sb.st_mode)) {
504 if (S_ISREG(sb.st_mode)) {
505 /* convert from old style */
506 if (unlink(timestampdir) == 0)
509 log_error(NO_EXIT, _("%s exists but is not a directory (0%o)"),
510 timestampdir, (unsigned int) sb.st_mode);
511 } else if (sb.st_uid != timestamp_uid)
512 log_error(NO_EXIT, _("%s owned by uid %u, should be uid %u"),
513 timestampdir, (unsigned int) sb.st_uid,
514 (unsigned int) timestamp_uid);
515 else if ((sb.st_mode & 0000022))
517 _("%s writable by non-owner (0%o), should be mode 0700"),
518 timestampdir, (unsigned int) sb.st_mode);
520 if ((sb.st_mode & 0000777) != 0700)
521 (void) chmod(timestampdir, 0700);
522 status = TS_OLD; /* do date check later */
524 } else if (errno != ENOENT) {
525 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), timestampdir);
530 * If there is no user ticket dir, AND we are in tty ticket mode,
531 * AND the TS_MAKE_DIRS flag is set, create the user ticket dir.
533 if (status == TS_MISSING && timestampfile && ISSET(flags, TS_MAKE_DIRS)) {
534 if (mkdir(timestampdir, S_IRWXU) == -1) {
536 log_error(NO_EXIT|USE_ERRNO, _("unable to mkdir %s"), timestampdir);
541 * Sanity check the tty ticket file if it exists.
543 if (timestampfile && status != TS_ERROR) {
544 if (status != TS_MISSING)
545 status = TS_NOFILE; /* dir there, file missing */
546 if (def_tty_tickets && !user_ttypath)
547 goto done; /* no tty, always prompt */
548 if (lstat(timestampfile, &sb) == 0) {
549 if (!S_ISREG(sb.st_mode)) {
551 log_error(NO_EXIT, _("%s exists but is not a regular file (0%o)"),
552 timestampfile, (unsigned int) sb.st_mode);
554 /* If bad uid or file mode, complain and kill the bogus file. */
555 if (sb.st_uid != timestamp_uid) {
557 _("%s owned by uid %u, should be uid %u"),
558 timestampfile, (unsigned int) sb.st_uid,
559 (unsigned int) timestamp_uid);
560 (void) unlink(timestampfile);
561 } else if ((sb.st_mode & 0000022)) {
563 _("%s writable by non-owner (0%o), should be mode 0600"),
564 timestampfile, (unsigned int) sb.st_mode);
565 (void) unlink(timestampfile);
567 /* If not mode 0600, fix it. */
568 if ((sb.st_mode & 0000777) != 0600)
569 (void) chmod(timestampfile, 0600);
572 * Check for stored tty info. If the file is zero-sized
573 * it is an old-style timestamp with no tty info in it.
574 * If removing, we don't care about the contents.
575 * The actual mtime check is done later.
577 if (ISSET(flags, TS_REMOVE)) {
579 } else if (sb.st_size != 0) {
580 struct tty_info info;
581 int fd = open(timestampfile, O_RDONLY, 0644);
583 if (read(fd, &info, sizeof(info)) == sizeof(info) &&
584 memcmp(&info, &tty_info, sizeof(info)) == 0) {
592 } else if (errno != ENOENT) {
593 log_error(NO_EXIT|USE_ERRNO, _("unable to stat %s"), timestampfile);
599 * If the file/dir exists and we are not removing it, check its mtime.
601 if (status == TS_OLD && !ISSET(flags, TS_REMOVE)) {
602 mtim_get(&sb, &mtime);
603 /* Negative timeouts only expire manually (sudo -k). */
604 if (def_timestamp_timeout < 0 && mtime.tv_sec != 0)
608 if (def_timestamp_timeout &&
609 now - mtime.tv_sec < 60 * def_timestamp_timeout) {
611 * Check for bogus time on the stampfile. The clock may
612 * have been set back or someone could be trying to spoof us.
614 if (mtime.tv_sec > now + 60 * def_timestamp_timeout * 2) {
615 time_t tv_sec = (time_t)mtime.tv_sec;
617 _("timestamp too far in the future: %20.20s"),
620 (void) unlink(timestampfile);
622 (void) rmdir(timestampdir);
624 } else if (get_boottime(&boottime) && timevalcmp(&mtime, &boottime, <)) {
634 if (timestamp_uid != 0)
640 * Remove the timestamp ticket file/dir.
643 remove_timestamp(int remove)
646 char *timestampdir, *timestampfile, *path;
649 if (build_timestamp(×tampdir, ×tampfile) == -1)
652 status = timestamp_status(timestampdir, timestampfile, user_name,
654 if (status != TS_MISSING && status != TS_ERROR) {
655 path = timestampfile ? timestampfile : timestampdir;
658 status = unlink(timestampfile);
660 status = rmdir(timestampdir);
661 if (status == -1 && errno != ENOENT) {
663 _("unable to remove %s (%s), will reset to the epoch"),
664 path, strerror(errno));
670 if (touch(-1, path, &tv) == -1 && errno != ENOENT)
671 error(1, _("unable to reset %s to the epoch"), path);
676 efree(timestampfile);
680 * Returns TRUE if tty lives on a devpts or /devices filesystem, else FALSE.
681 * Unlike most filesystems, the ctime of devpts nodes is not updated when
682 * the device node is written to, only when the inode's status changes,
683 * typically via the chmod, chown, link, rename, or utimes system calls.
684 * Since the ctime is "stable" in this case, we can stash it the tty ticket
685 * file and use it to determine whether the tty ticket file is stale.
688 tty_is_devpts(const char *tty)
694 #ifndef DEVPTS_SUPER_MAGIC
695 # define DEVPTS_SUPER_MAGIC 0x1cd1
698 if (statfs(tty, &sfs) == 0) {
699 if (sfs.f_type == DEVPTS_SUPER_MAGIC)
702 #elif defined(__sun) && defined(__SVR4)
705 if (statvfs(tty, &sfs) == 0) {
706 if (strcmp(sfs.f_fstr, "devices") == 0)
709 #endif /* __linux__ */
714 * Get passwd entry for the user we are going to authenticate as.
715 * By default, this is the user invoking sudo. In the most common
716 * case, this matches sudo_user.pw or runas_pw.
718 static struct passwd *
724 if ((pw = sudo_getpwuid(ROOT_UID)) == NULL)
725 log_error(0, _("unknown uid: %u"), ROOT_UID);
726 } else if (def_runaspw) {
727 if ((pw = sudo_getpwnam(def_runas_default)) == NULL)
728 log_error(0, _("unknown user: %s"), def_runas_default);
729 } else if (def_targetpw) {
730 if (runas_pw->pw_name == NULL)
731 log_error(NO_MAIL|MSG_ONLY, _("unknown uid: %u"),
732 (unsigned int) runas_pw->pw_uid);
736 pw_addref(sudo_user.pw);