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/*
* Copyright (c) 1994-1996,1998-2003 Todd C. Miller <Todd.Miller@courtesan.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 4. Products derived from this software may not be called "Sudo" nor
* may "Sudo" appear in their names without specific prior written
* permission from the author.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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>
#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 <pwd.h>
#include <errno.h>
#include <grp.h>
#ifdef HAVE_LOGIN_CAP_H
# include <login_cap.h>
#endif
#include "sudo.h"
#ifndef lint
static const char rcsid[] = "$Sudo: set_perms.c,v 1.21 2003/04/16 00:42:10 millert Exp $";
#endif /* lint */
/*
* Prototypes
*/
static void runas_setup __P((void));
static void fatal __P((char *, int));
#if !defined(HAVE_SETRESUID) && !defined(HAVE_SETREUID) && \
!defined(NO_SAVED_IDS) && defined(_SC_SAVED_IDS) && defined(_SC_VERSION)
/*
* Set real and effective uids and gids based on perm.
* Since we have POSIX saved IDs we can get away with just
* toggling the effective uid/gid unless we are headed for an exec().
*/
void
set_perms_posix(perm)
int perm;
{
int error;
switch (perm) {
case PERM_ROOT:
if (seteuid(0))
fatal("seteuid(0) failed, your operating system may have broken POSIX saved ID support\nTry running configure with --disable-saved-ids", 0);
break;
case PERM_FULL_ROOT:
/* headed for exec() */
(void) seteuid(0);
if (setuid(0))
fatal("setuid(0)", 1);
break;
case PERM_USER:
(void) setegid(user_gid);
if (seteuid(user_uid))
fatal("seteuid(user_uid)", 1);
break;
case PERM_FULL_USER:
/* headed for exec() */
(void) setgid(user_gid);
if (setuid(user_uid))
fatal("setuid(user_uid)", 1);
break;
case PERM_RUNAS:
/* headed for exec(), assume euid == 0 */
runas_setup();
if (def_flag(I_STAY_SETUID))
error = seteuid(runas_pw->pw_uid);
else
error = setuid(runas_pw->pw_uid);
if (error)
fatal("unable to change to runas uid", 1);
break;
case PERM_SUDOERS:
/* assume euid == 0, ruid == user */
if (setegid(SUDOERS_GID))
fatal("unable to change to sudoers gid", 1);
/*
* If SUDOERS_UID == 0 and SUDOERS_MODE
* is group readable we use a non-zero
* uid in order to avoid NFS lossage.
* Using uid 1 is a bit bogus but should
* work on all OS's.
*/
if (SUDOERS_UID == 0) {
if ((SUDOERS_MODE & 040) && seteuid(1))
fatal("seteuid(1)", 1);
} else {
if (seteuid(SUDOERS_UID))
fatal("seteuid(SUDOERS_UID)", 1);
}
break;
case PERM_TIMESTAMP:
if (seteuid(timestamp_uid))
fatal("seteuid(timestamp_uid)", 1);
break;
}
}
#endif /* !NO_SAVED_IDS && _SC_SAVED_IDS && _SC_VERSION */
#ifdef HAVE_SETRESUID
/*
* Set real and effective and saved uids and gids based on perm.
* We always retain a saved uid of 0 unless we are headed for an exec().
* We only flip the effective gid since it only changes for PERM_SUDOERS.
* This version of set_perms() works fine with the "stay_setuid" option.
*/
void
set_perms_suid(perm)
int perm;
{
int error;
switch (perm) {
case PERM_FULL_ROOT:
case PERM_ROOT:
if (setresuid(0, 0, 0))
fatal("setresuid(0, 0, 0) failed, your operating system may have a broken setresuid() function\nTry running configure with --disable-setresuid", 0);
break;
case PERM_USER:
(void) setresgid(-1, user_gid, -1);
if (setresuid(user_uid, user_uid, 0))
fatal("setresuid(user_uid, user_uid, 0)", 1);
break;
case PERM_FULL_USER:
/* headed for exec() */
(void) setgid(user_gid);
if (setresuid(user_uid, user_uid, user_uid))
fatal("setresuid(user_uid, user_uid, user_uid)", 1);
break;
case PERM_RUNAS:
/* headed for exec(), assume euid == 0 */
runas_setup();
error = setresuid(def_flag(I_STAY_SETUID) ?
user_uid : runas_pw->pw_uid,
runas_pw->pw_uid, runas_pw->pw_uid);
if (error)
fatal("unable to change to runas uid", 1);
break;
case PERM_SUDOERS:
/* assume euid == 0, ruid == user */
if (setresgid(-1, SUDOERS_GID, -1))
fatal("unable to change to sudoers gid", 1);
/*
* If SUDOERS_UID == 0 and SUDOERS_MODE
* is group readable we use a non-zero
* uid in order to avoid NFS lossage.
* Using uid 1 is a bit bogus but should
* work on all OS's.
*/
if (SUDOERS_UID == 0) {
if ((SUDOERS_MODE & 040) && setresuid(0, 1, 0))
fatal("setresuid(0, 1, 0)", 1);
} else {
if (setresuid(0, SUDOERS_UID, 0))
fatal("setresuid(0, SUDOERS_UID, 0)", 1);
}
break;
case PERM_TIMESTAMP:
if (setresuid(0, timestamp_uid, 0))
fatal("setresuid(0, timestamp_uid, 0)", 1);
break;
}
}
#else
# ifdef HAVE_SETREUID
/*
* Set real and effective uids and gids based on perm.
* We always retain a real or effective uid of 0 unless
* we are headed for an exec().
* This version of set_perms() works fine with the "stay_setuid" option.
*/
void
set_perms_suid(perm)
int perm;
{
int error;
switch (perm) {
case PERM_FULL_ROOT:
case PERM_ROOT:
if (setreuid(0, 0))
fatal("setreuid(0, 0) failed, your operating system may have a broken setreuid() function\nTry running configure with --disable-setreuid", 0);
break;
case PERM_USER:
(void) setregid(-1, user_gid);
if (setreuid(0, user_uid))
fatal("setreuid(0, user_uid)", 1);
break;
case PERM_FULL_USER:
/* headed for exec() */
(void) setgid(user_gid);
if (setreuid(user_uid, user_uid))
fatal("setreuid(user_uid, user_uid)", 1);
break;
case PERM_RUNAS:
/* headed for exec(), assume euid == 0 */
runas_setup();
error = setreuid(def_flag(I_STAY_SETUID) ?
user_uid : runas_pw->pw_uid,
runas_pw->pw_uid);
if (error)
fatal("unable to change to runas uid", 1);
break;
case PERM_SUDOERS:
/* assume euid == 0, ruid == user */
if (setregid(-1, SUDOERS_GID))
fatal("unable to change to sudoers gid", 1);
/*
* If SUDOERS_UID == 0 and SUDOERS_MODE
* is group readable we use a non-zero
* uid in order to avoid NFS lossage.
* Using uid 1 is a bit bogus but should
* work on all OS's.
*/
if (SUDOERS_UID == 0) {
if ((SUDOERS_MODE & 040) && setreuid(0, 1))
fatal("setreuid(0, 1)", 1);
} else {
if (setreuid(0, SUDOERS_UID))
fatal("setreuid(0, SUDOERS_UID)", 1);
}
break;
case PERM_TIMESTAMP:
if (setreuid(0, timestamp_uid))
fatal("setreuid(0, timestamp_uid)", 1);
break;
}
}
# else
/*
* Set real and effective uids and gids based on perm.
* NOTE: does not support the "stay_setuid" option.
*/
void
set_perms_nosuid(perm)
int perm;
{
/*
* Since we only have setuid() and seteuid() we have to set
* real and effective uids to 0 initially.
*/
if (setuid(0))
fatal("setuid(0)", 1);
switch (perm) {
case PERM_USER:
(void) setegid(user_gid);
if (seteuid(user_uid))
fatal("seteuid(user_uid)", 1);
break;
case PERM_FULL_USER:
/* headed for exec() */
(void) setgid(user_gid);
if (setuid(user_uid))
fatal("setuid(user_uid)", 1);
break;
case PERM_RUNAS:
/* headed for exec(), assume euid == 0 */
runas_setup();
if (setuid(runas_pw->pw_uid))
fatal("unable to change to runas uid", 1);
break;
case PERM_SUDOERS:
/* assume euid == 0, ruid == user */
if (setegid(SUDOERS_GID))
fatal("unable to change to sudoers gid", 1);
/*
* If SUDOERS_UID == 0 and SUDOERS_MODE
* is group readable we use a non-zero
* uid in order to avoid NFS lossage.
* Using uid 1 is a bit bogus but should
* work on all OS's.
*/
if (SUDOERS_UID == 0) {
if ((SUDOERS_MODE & 040) && seteuid(1))
fatal("seteuid(1)", 1);
} else {
if (seteuid(SUDOERS_UID))
fatal("seteuid(SUDOERS_UID)", 1);
}
break;
case PERM_TIMESTAMP:
if (seteuid(timestamp_uid))
fatal("seteuid(timestamp_uid)", 1);
break;
}
}
# endif /* HAVE_SETREUID */
#endif /* HAVE_SETRESUID */
static void
runas_setup()
{
#ifdef HAVE_LOGIN_CAP_H
int error, flags;
extern login_cap_t *lc;
#endif
if (runas_pw->pw_name != NULL) {
#ifdef HAVE_PAM
pam_prep_user(runas_pw);
#endif /* HAVE_PAM */
#ifdef HAVE_LOGIN_CAP_H
if (def_flag(I_USE_LOGINCLASS)) {
/*
* We don't have setusercontext() set the user since we
* may only want to set the effective uid. Depending on
* sudoers and/or command line arguments we may not want
* setusercontext() to call initgroups().
*/
flags = LOGIN_SETRESOURCES|LOGIN_SETPRIORITY;
if (!def_flag(I_PRESERVE_GROUPS))
flags |= LOGIN_SETGROUP;
else if (setgid(runas_pw->pw_gid))
perror("cannot set gid to runas gid");
error = setusercontext(lc, runas_pw,
runas_pw->pw_uid, flags);
if (error) {
if (runas_pw->pw_uid != 0)
fatal("unable to set user context", 1);
else
perror("unable to set user context");
}
} else
#endif /* HAVE_LOGIN_CAP_H */
{
if (setgid(runas_pw->pw_gid))
perror("cannot set gid to runas gid");
#ifdef HAVE_INITGROUPS
/*
* Initialize group vector unless asked not to.
*/
if (!def_flag(I_PRESERVE_GROUPS) &&
initgroups(*user_runas, runas_pw->pw_gid) < 0)
perror("cannot set group vector");
#endif /* HAVE_INITGROUPS */
}
}
}
static void
fatal(str, printerr)
char *str;
int printerr;
{
if (str) {
if (printerr)
perror(str);
else {
fputs(str, stderr);
fputc('\n', stderr);
}
}
exit(1);
}
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