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Rework source layout in preparation for modular sudo.

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This commit is contained in:
Todd C. Miller
2010-02-20 09:14:01 -05:00
parent 28c24027ec
commit e90fa482f9
151 changed files with 0 additions and 0 deletions
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plugins/sudoers/check.c Normal file
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/*
* Copyright (c) 1993-1996,1998-2005, 2007-2009
* Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include <config.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#ifndef __TANDEM
# include <sys/file.h>
#endif
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#ifdef HAVE_STRING_H
# include <string.h>
#else
# ifdef HAVE_STRINGS_H
# include <strings.h>
# endif
#endif /* HAVE_STRING_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#ifndef HAVE_TIMESPEC
# include <emul/timespec.h>
#endif
#include "sudo.h"
/* Status codes for timestamp_status() */
#define TS_CURRENT 0
#define TS_OLD 1
#define TS_MISSING 2
#define TS_NOFILE 3
#define TS_ERROR 4
/* Flags for timestamp_status() */
#define TS_MAKE_DIRS 1
#define TS_REMOVE 2
static void build_timestamp __P((char **, char **));
static int timestamp_status __P((char *, char *, char *, int));
static char *expand_prompt __P((char *, char *, char *));
static void lecture __P((int));
static void update_timestamp __P((char *, char *));
/*
* This function only returns if the user can successfully
* verify who he/she is.
*/
void
check_user(validated, mode)
int validated;
int mode;
{
char *timestampdir = NULL;
char *timestampfile = NULL;
char *prompt;
int status;
/* Always prompt for a password when -k was specified with the command. */
if (ISSET(mode, MODE_INVALIDATE)) {
SET(validated, FLAG_CHECK_USER);
} else {
if (user_uid == 0 || user_uid == runas_pw->pw_uid || user_is_exempt())
return;
}
build_timestamp(&timestampdir, &timestampfile);
status = timestamp_status(timestampdir, timestampfile, user_name,
TS_MAKE_DIRS);
if (status != TS_CURRENT || ISSET(validated, FLAG_CHECK_USER)) {
/* Bail out if we are non-interactive and a password is required */
if (ISSET(mode, MODE_NONINTERACTIVE))
errorx(1, "sorry, a password is required to run %s", getprogname());
/* If user specified -A, make sure we have an askpass helper. */
if (ISSET(tgetpass_flags, TGP_ASKPASS)) {
if (user_askpass == NULL)
log_error(NO_MAIL,
"no askpass program specified, try setting SUDO_ASKPASS");
} else if (!ISSET(tgetpass_flags, TGP_STDIN)) {
/* If no tty but DISPLAY is set, use askpass if we have it. */
if (!user_ttypath && !tty_present()) {
if (user_askpass && user_display && *user_display != '\0') {
SET(tgetpass_flags, TGP_ASKPASS);
} else if (!def_visiblepw) {
log_error(NO_MAIL,
"no tty present and no askpass program specified");
}
}
}
if (!ISSET(tgetpass_flags, TGP_ASKPASS))
lecture(status);
/* Expand any escapes in the prompt. */
prompt = expand_prompt(user_prompt ? user_prompt : def_passprompt,
user_name, user_shost);
verify_user(auth_pw, prompt);
}
/* Only update timestamp if user was validated. */
if (ISSET(validated, VALIDATE_OK) && !ISSET(mode, MODE_INVALIDATE) && status != TS_ERROR)
update_timestamp(timestampdir, timestampfile);
efree(timestampdir);
efree(timestampfile);
}
/*
* Standard sudo lecture.
*/
static void
lecture(status)
int status;
{
FILE *fp;
char buf[BUFSIZ];
ssize_t nread;
if (def_lecture == never ||
(def_lecture == once && status != TS_MISSING && status != TS_ERROR))
return;
if (def_lecture_file && (fp = fopen(def_lecture_file, "r")) != NULL) {
while ((nread = fread(buf, sizeof(char), sizeof(buf), fp)) != 0)
fwrite(buf, nread, 1, stderr);
fclose(fp);
} else {
(void) fputs("\n\
We trust you have received the usual lecture from the local System\n\
Administrator. It usually boils down to these three things:\n\
\n\
#1) Respect the privacy of others.\n\
#2) Think before you type.\n\
#3) With great power comes great responsibility.\n\n",
stderr);
}
}
/*
* Update the time on the timestamp file/dir or create it if necessary.
*/
static void
update_timestamp(timestampdir, timestampfile)
char *timestampdir;
char *timestampfile;
{
if (timestamp_uid != 0)
set_perms(PERM_TIMESTAMP);
if (touch(-1, timestampfile ? timestampfile : timestampdir, NULL) == -1) {
if (timestampfile) {
int fd = open(timestampfile, O_WRONLY|O_CREAT|O_TRUNC, 0600);
if (fd == -1)
log_error(NO_EXIT|USE_ERRNO, "Can't open %s", timestampfile);
else
close(fd);
} else {
if (mkdir(timestampdir, 0700) == -1)
log_error(NO_EXIT|USE_ERRNO, "Can't mkdir %s", timestampdir);
}
}
if (timestamp_uid != 0)
set_perms(PERM_ROOT);
}
/*
* Expand %h and %u escapes in the prompt and pass back the dynamically
* allocated result. Returns the same string if there are no escapes.
*/
static char *
expand_prompt(old_prompt, user, host)
char *old_prompt;
char *user;
char *host;
{
size_t len, n;
int subst;
char *p, *np, *new_prompt, *endp;
/* How much space do we need to malloc for the prompt? */
subst = 0;
for (p = old_prompt, len = strlen(old_prompt); *p; p++) {
if (p[0] =='%') {
switch (p[1]) {
case 'h':
p++;
len += strlen(user_shost) - 2;
subst = 1;
break;
case 'H':
p++;
len += strlen(user_host) - 2;
subst = 1;
break;
case 'p':
p++;
if (def_rootpw)
len += 2;
else if (def_targetpw || def_runaspw)
len += strlen(runas_pw->pw_name) - 2;
else
len += strlen(user_name) - 2;
subst = 1;
break;
case 'u':
p++;
len += strlen(user_name) - 2;
subst = 1;
break;
case 'U':
p++;
len += strlen(runas_pw->pw_name) - 2;
subst = 1;
break;
case '%':
p++;
len--;
subst = 1;
break;
default:
break;
}
}
}
if (subst) {
new_prompt = (char *) emalloc(++len);
endp = new_prompt + len;
for (p = old_prompt, np = new_prompt; *p; p++) {
if (p[0] =='%') {
switch (p[1]) {
case 'h':
p++;
n = strlcpy(np, user_shost, np - endp);
if (n >= np - endp)
goto oflow;
np += n;
continue;
case 'H':
p++;
n = strlcpy(np, user_host, np - endp);
if (n >= np - endp)
goto oflow;
np += n;
continue;
case 'p':
p++;
if (def_rootpw)
n = strlcpy(np, "root", np - endp);
else if (def_targetpw || def_runaspw)
n = strlcpy(np, runas_pw->pw_name, np - endp);
else
n = strlcpy(np, user_name, np - endp);
if (n >= np - endp)
goto oflow;
np += n;
continue;
case 'u':
p++;
n = strlcpy(np, user_name, np - endp);
if (n >= np - endp)
goto oflow;
np += n;
continue;
case 'U':
p++;
n = strlcpy(np, runas_pw->pw_name, np - endp);
if (n >= np - endp)
goto oflow;
np += n;
continue;
case '%':
/* convert %% -> % */
p++;
break;
default:
/* no conversion */
break;
}
}
*np++ = *p;
if (np >= endp)
goto oflow;
}
*np = '\0';
} else
new_prompt = old_prompt;
return(new_prompt);
oflow:
/* We pre-allocate enough space, so this should never happen. */
errorx(1, "internal error, expand_prompt() overflow");
}
/*
* Checks if the user is exempt from supplying a password.
*/
int
user_is_exempt()
{
if (!def_exempt_group)
return(FALSE);
return(user_in_group(sudo_user.pw, def_exempt_group));
}
/*
* Fills in timestampdir as well as timestampfile if using tty tickets.
*/
static void
build_timestamp(timestampdir, timestampfile)
char **timestampdir;
char **timestampfile;
{
char *dirparent;
int len;
dirparent = def_timestampdir;
len = easprintf(timestampdir, "%s/%s", dirparent, user_name);
if (len >= PATH_MAX)
log_error(0, "timestamp path too long: %s", *timestampdir);
/*
* Timestamp file may be a file in the directory or NUL to use
* the directory as the timestamp.
*/
if (def_tty_tickets) {
char *p;
if ((p = strrchr(user_tty, '/')))
p++;
else
p = user_tty;
if (def_targetpw)
len = easprintf(timestampfile, "%s/%s/%s:%s", dirparent, user_name,
p, runas_pw->pw_name);
else
len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name, p);
if (len >= PATH_MAX)
log_error(0, "timestamp path too long: %s", *timestampfile);
} else if (def_targetpw) {
len = easprintf(timestampfile, "%s/%s/%s", dirparent, user_name,
runas_pw->pw_name);
if (len >= PATH_MAX)
log_error(0, "timestamp path too long: %s", *timestampfile);
} else
*timestampfile = NULL;
}
/*
* Check the timestamp file and directory and return their status.
*/
static int
timestamp_status(timestampdir, timestampfile, user, flags)
char *timestampdir;
char *timestampfile;
char *user;
int flags;
{
struct stat sb;
time_t boottime, now;
char *dirparent = def_timestampdir;
int status = TS_ERROR; /* assume the worst */
if (timestamp_uid != 0)
set_perms(PERM_TIMESTAMP);
/*
* Sanity check dirparent and make it if it doesn't already exist.
* We start out assuming the worst (that the dir is not sane) and
* if it is ok upgrade the status to ``no timestamp file''.
* Note that we don't check the parent(s) of dirparent for
* sanity since the sudo dir is often just located in /tmp.
*/
if (lstat(dirparent, &sb) == 0) {
if (!S_ISDIR(sb.st_mode))
log_error(NO_EXIT, "%s exists but is not a directory (0%o)",
dirparent, (unsigned int) sb.st_mode);
else if (sb.st_uid != timestamp_uid)
log_error(NO_EXIT, "%s owned by uid %lu, should be uid %lu",
dirparent, (unsigned long) sb.st_uid,
(unsigned long) timestamp_uid);
else if ((sb.st_mode & 0000022))
log_error(NO_EXIT,
"%s writable by non-owner (0%o), should be mode 0700",
dirparent, (unsigned int) sb.st_mode);
else {
if ((sb.st_mode & 0000777) != 0700)
(void) chmod(dirparent, 0700);
status = TS_MISSING;
}
} else if (errno != ENOENT) {
log_error(NO_EXIT|USE_ERRNO, "can't stat %s", dirparent);
} else {
/* No dirparent, try to make one. */
if (ISSET(flags, TS_MAKE_DIRS)) {
if (mkdir(dirparent, S_IRWXU))
log_error(NO_EXIT|USE_ERRNO, "can't mkdir %s",
dirparent);
else
status = TS_MISSING;
}
}
if (status == TS_ERROR) {
if (timestamp_uid != 0)
set_perms(PERM_ROOT);
return(status);
}
/*
* Sanity check the user's ticket dir. We start by downgrading
* the status to TS_ERROR. If the ticket dir exists and is sane
* this will be upgraded to TS_OLD. If the dir does not exist,
* it will be upgraded to TS_MISSING.
*/
status = TS_ERROR; /* downgrade status again */
if (lstat(timestampdir, &sb) == 0) {
if (!S_ISDIR(sb.st_mode)) {
if (S_ISREG(sb.st_mode)) {
/* convert from old style */
if (unlink(timestampdir) == 0)
status = TS_MISSING;
} else
log_error(NO_EXIT, "%s exists but is not a directory (0%o)",
timestampdir, (unsigned int) sb.st_mode);
} else if (sb.st_uid != timestamp_uid)
log_error(NO_EXIT, "%s owned by uid %lu, should be uid %lu",
timestampdir, (unsigned long) sb.st_uid,
(unsigned long) timestamp_uid);
else if ((sb.st_mode & 0000022))
log_error(NO_EXIT,
"%s writable by non-owner (0%o), should be mode 0700",
timestampdir, (unsigned int) sb.st_mode);
else {
if ((sb.st_mode & 0000777) != 0700)
(void) chmod(timestampdir, 0700);
status = TS_OLD; /* do date check later */
}
} else if (errno != ENOENT) {
log_error(NO_EXIT|USE_ERRNO, "can't stat %s", timestampdir);
} else
status = TS_MISSING;
/*
* If there is no user ticket dir, AND we are in tty ticket mode,
* AND the TS_MAKE_DIRS flag is set, create the user ticket dir.
*/
if (status == TS_MISSING && timestampfile && ISSET(flags, TS_MAKE_DIRS)) {
if (mkdir(timestampdir, S_IRWXU) == -1) {
status = TS_ERROR;
log_error(NO_EXIT|USE_ERRNO, "can't mkdir %s", timestampdir);
}
}
/*
* Sanity check the tty ticket file if it exists.
*/
if (timestampfile && status != TS_ERROR) {
if (status != TS_MISSING)
status = TS_NOFILE; /* dir there, file missing */
if (!user_ttypath)
goto done; /* no tty, always prompt */
if (lstat(timestampfile, &sb) == 0) {
if (!S_ISREG(sb.st_mode)) {
status = TS_ERROR;
log_error(NO_EXIT, "%s exists but is not a regular file (0%o)",
timestampfile, (unsigned int) sb.st_mode);
} else {
/* If bad uid or file mode, complain and kill the bogus file. */
if (sb.st_uid != timestamp_uid) {
log_error(NO_EXIT,
"%s owned by uid %lu, should be uid %lu",
timestampfile, (unsigned long) sb.st_uid,
(unsigned long) timestamp_uid);
(void) unlink(timestampfile);
} else if ((sb.st_mode & 0000022)) {
log_error(NO_EXIT,
"%s writable by non-owner (0%o), should be mode 0600",
timestampfile, (unsigned int) sb.st_mode);
(void) unlink(timestampfile);
} else {
/* If not mode 0600, fix it. */
if ((sb.st_mode & 0000777) != 0600)
(void) chmod(timestampfile, 0600);
status = TS_OLD; /* actually check mtime below */
}
}
} else if (errno != ENOENT) {
log_error(NO_EXIT|USE_ERRNO, "can't stat %s", timestampfile);
status = TS_ERROR;
}
}
/*
* If the file/dir exists and we are not removing it, check its mtime.
*/
if (status == TS_OLD && !ISSET(flags, TS_REMOVE)) {
/* Negative timeouts only expire manually (sudo -k). */
if (def_timestamp_timeout < 0 && sb.st_mtime != 0)
status = TS_CURRENT;
else {
/* XXX - should use timespec here */
now = time(NULL);
boottime = get_boottime();
if (def_timestamp_timeout &&
now - sb.st_mtime < 60 * def_timestamp_timeout) {
/*
* Check for bogus time on the stampfile. The clock may
* have been set back or someone could be trying to spoof us.
*/
if (sb.st_mtime > now + 60 * def_timestamp_timeout * 2) {
log_error(NO_EXIT,
"timestamp too far in the future: %20.20s",
4 + ctime(&sb.st_mtime));
if (timestampfile)
(void) unlink(timestampfile);
else
(void) rmdir(timestampdir);
status = TS_MISSING;
} else if (sb.st_mtime < boottime) {
status = TS_OLD;
} else {
status = TS_CURRENT;
}
}
}
}
done:
if (timestamp_uid != 0)
set_perms(PERM_ROOT);
return(status);
}
/*
* Remove the timestamp ticket file/dir.
*/
void
remove_timestamp(remove)
int remove;
{
struct timespec ts;
char *timestampdir, *timestampfile, *path;
int status;
build_timestamp(&timestampdir, &timestampfile);
status = timestamp_status(timestampdir, timestampfile, user_name,
TS_REMOVE);
if (status == TS_OLD || status == TS_CURRENT) {
path = timestampfile ? timestampfile : timestampdir;
if (remove) {
if (timestampfile)
status = unlink(timestampfile);
else
status = rmdir(timestampdir);
if (status == -1 && errno != ENOENT) {
log_error(NO_EXIT, "can't remove %s (%s), will reset to Epoch",
path, strerror(errno));
remove = FALSE;
}
} else {
timespecclear(&ts);
if (touch(-1, path, &ts) == -1)
error(1, "can't reset %s to Epoch", path);
}
}
efree(timestampdir);
efree(timestampfile);
}