b152da4cdb
when possible since that allows us to support the stay_setuid option and we always know exactly what the semantics will be (various Linux kernels have broken POSIX saved uid support).
432 lines
11 KiB
C
432 lines
11 KiB
C
/*
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* Copyright (c) 1994-1996,1998-2001 Todd C. Miller <Todd.Miller@courtesan.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* 4. Products derived from this software may not be called "Sudo" nor
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* may "Sudo" appear in their names without specific prior written
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* permission from the author.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "config.h"
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <stdio.h>
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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# include <stddef.h>
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#else
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# ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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# endif
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#endif /* STDC_HEADERS */
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#ifdef HAVE_STRING_H
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# include <string.h>
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#else
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# ifdef HAVE_STRINGS_H
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# include <strings.h>
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# endif
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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#include <pwd.h>
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#include <errno.h>
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#include <grp.h>
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#ifdef HAVE_LOGIN_CAP_H
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# include <login_cap.h>
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#endif
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#include "sudo.h"
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#ifndef lint
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static const char rcsid[] = "$Sudo$";
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#endif /* lint */
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/*
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* Prototypes
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*/
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static void runas_setup __P((void));
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static void fatal __P((char *, int));
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#if !defined(NO_SAVED_IDS) && defined(_SC_SAVED_IDS) && defined(_SC_VERSION)
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/*
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* Set real and effective uids and gids based on perm.
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* Since we have POSIX saved IDs we can get away with just
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* toggling the effective uid/gid unless we are headed for an exec().
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*/
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void
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set_perms_posix(perm)
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int perm;
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{
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int error;
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switch (perm) {
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case PERM_ROOT:
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if (seteuid(0))
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fatal("seteuid(0) failed, your operating system may have broken POSIX saved ID support\nTry running configure with --disable-saved-ids", 0);
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break;
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case PERM_FULL_ROOT:
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/* headed for exec() */
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(void) seteuid(0);
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if (setuid(0))
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fatal("setuid(0)", 1);
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break;
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case PERM_USER:
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(void) setegid(user_gid);
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if (seteuid(user_uid))
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fatal("seteuid(user_uid)", 1);
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break;
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case PERM_FULL_USER:
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/* headed for exec() */
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(void) setgid(user_gid);
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if (setuid(user_uid))
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fatal("setuid(user_uid)", 1);
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break;
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case PERM_RUNAS:
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/* headed for exec(), assume euid == 0 */
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runas_setup();
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if (def_flag(I_STAY_SETUID))
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error = seteuid(runas_pw->pw_uid);
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else
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error = setuid(runas_pw->pw_uid);
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if (error)
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fatal("unable to change to runas uid", 1);
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break;
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case PERM_SUDOERS:
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/* assume euid == 0, ruid == user */
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if (setegid(SUDOERS_GID))
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fatal("unable to change to sudoers gid", 1);
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/*
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* If SUDOERS_UID == 0 and SUDOERS_MODE
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* is group readable we use a non-zero
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* uid in order to avoid NFS lossage.
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* Using uid 1 is a bit bogus but should
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* work on all OS's.
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*/
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if (SUDOERS_UID == 0) {
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if ((SUDOERS_MODE & 040) && seteuid(1))
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fatal("seteuid(1)", 1);
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} else {
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if (seteuid(SUDOERS_UID))
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fatal("seteuid(SUDOERS_UID)", 1);
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}
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break;
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case PERM_TIMESTAMP:
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if (seteuid(timestamp_uid))
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fatal("seteuid(timestamp_uid)", 1);
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break;
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}
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}
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#endif /* !NO_SAVED_IDS && _SC_SAVED_IDS && _SC_VERSION */
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#ifdef HAVE_SETRESUID
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/*
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* Set real and effective and saved uids and gids based on perm.
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* We always retain a saved uid of 0 unless we are headed for an exec().
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* We only flip the effective gid since it only changes for PERM_SUDOERS.
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* This version of set_perms() works fine with the "stay_setuid" option.
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*/
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void
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set_perms_suid(perm)
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int perm;
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{
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int error;
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switch (perm) {
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case PERM_FULL_ROOT:
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case PERM_ROOT:
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if (setresuid(0, 0, 0))
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fatal("setresuid(0, 0, 0) failed, your operating system may have a broken setresuid() function\nTry running configure with --disable-setresuid", 0);
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break;
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case PERM_USER:
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(void) setresgid(user_gid, -1, -1);
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if (setresuid(user_uid, user_uid, 0))
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fatal("setresuid(user_uid, user_uid, 0)", 1);
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break;
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case PERM_FULL_USER:
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/* headed for exec() */
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(void) setgid(user_gid);
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if (setresuid(user_uid, user_uid, user_uid))
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fatal("setresuid(user_uid, user_uid, user_uid)", 1);
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break;
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case PERM_RUNAS:
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/* headed for exec(), assume euid == 0 */
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runas_setup();
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error = setresuid(def_flag(I_STAY_SETUID) ?
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user_uid : runas_pw->pw_uid,
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runas_pw->pw_uid, runas_pw->pw_uid);
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if (error)
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fatal("unable to change to runas uid", 1);
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break;
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case PERM_SUDOERS:
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/* assume euid == 0, ruid == user */
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if (setresgid(SUDOERS_GID, -1, -1))
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fatal("unable to change to sudoers gid", 1);
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/*
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* If SUDOERS_UID == 0 and SUDOERS_MODE
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* is group readable we use a non-zero
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* uid in order to avoid NFS lossage.
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* Using uid 1 is a bit bogus but should
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* work on all OS's.
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*/
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if (SUDOERS_UID == 0) {
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if ((SUDOERS_MODE & 040) && setresuid(0, 1, 0))
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fatal("setresuid(0, 1, 0)", 1);
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} else {
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if (setresuid(0, SUDOERS_UID, 0))
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fatal("setresuid(0, SUDOERS_UID, 0)", 1);
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}
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break;
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case PERM_TIMESTAMP:
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if (setresuid(0, timestamp_uid, 0))
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fatal("setresuid(0, timestamp_uid, 0)", 1);
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break;
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}
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}
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#else
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# ifdef HAVE_SETREUID
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/*
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* Set real and effective uids and gids based on perm.
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* We always retain a real or effective uid of 0 unless
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* we are headed for an exec().
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* This version of set_perms() works fine with the "stay_setuid" option.
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*/
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void
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set_perms_suid(perm)
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int perm;
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{
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int error;
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switch (perm) {
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case PERM_FULL_ROOT:
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case PERM_ROOT:
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if (setreuid(0, 0))
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fatal("setreuid(0, 0) failed, your operating system may have a broken setreuid() function\nTry running configure with --disable-setreuid", 0);
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break;
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case PERM_USER:
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(void) setregid(user_gid, -1);
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if (setreuid(0, user_uid))
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fatal("setreuid(0, user_uid)", 1);
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break;
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case PERM_FULL_USER:
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/* headed for exec() */
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(void) setgid(user_gid);
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if (setreuid(user_uid, user_uid))
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fatal("setreuid(user_uid, user_uid)", 1);
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break;
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case PERM_RUNAS:
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/* headed for exec(), assume euid == 0 */
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runas_setup();
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error = setreuid(def_flag(I_STAY_SETUID) ?
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user_uid : runas_pw->pw_uid,
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runas_pw->pw_uid);
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if (error)
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fatal("unable to change to runas uid", 1);
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break;
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case PERM_SUDOERS:
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/* assume euid == 0, ruid == user */
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if (setregid(SUDOERS_GID, -1))
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fatal("unable to change to sudoers gid", 1);
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/*
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* If SUDOERS_UID == 0 and SUDOERS_MODE
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* is group readable we use a non-zero
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* uid in order to avoid NFS lossage.
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* Using uid 1 is a bit bogus but should
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* work on all OS's.
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*/
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if (SUDOERS_UID == 0) {
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if ((SUDOERS_MODE & 040) && setreuid(0, 1))
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fatal("setreuid(0, 1)", 1);
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} else {
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if (setreuid(0, SUDOERS_UID))
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fatal("setreuid(0, SUDOERS_UID)", 1);
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}
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break;
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case PERM_TIMESTAMP:
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if (setreuid(0, timestamp_uid))
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fatal("setreuid(0, timestamp_uid)", 1);
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break;
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}
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}
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# else
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/*
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* Set real and effective uids and gids based on perm.
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* NOTE: does not support the "stay_setuid" option.
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*/
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void
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set_perms_nosuid(perm)
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int perm;
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{
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/*
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* Since we only have setuid() and seteuid() we have to set
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* real and effective uids to 0 initially.
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*/
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if (setuid(0))
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fatal("setuid(0)", 1);
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switch (perm) {
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case PERM_USER:
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(void) setegid(user_gid);
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if (seteuid(user_uid))
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fatal("seteuid(user_uid)", 1);
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break;
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case PERM_FULL_USER:
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/* headed for exec() */
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(void) setgid(user_gid);
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if (setuid(user_uid))
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fatal("setuid(user_uid)", 1);
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break;
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case PERM_RUNAS:
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/* headed for exec(), assume euid == 0 */
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runas_setup();
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if (setuid(runas_pw->pw_uid))
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fatal("unable to change to runas uid", 1);
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break;
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case PERM_SUDOERS:
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/* assume euid == 0, ruid == user */
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if (setegid(SUDOERS_GID))
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fatal("unable to change to sudoers gid", 1);
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/*
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* If SUDOERS_UID == 0 and SUDOERS_MODE
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* is group readable we use a non-zero
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* uid in order to avoid NFS lossage.
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* Using uid 1 is a bit bogus but should
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* work on all OS's.
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*/
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if (SUDOERS_UID == 0) {
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if ((SUDOERS_MODE & 040) && seteuid(1))
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fatal("seteuid(1)", 1);
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} else {
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if (seteuid(SUDOERS_UID))
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fatal("seteuid(SUDOERS_UID)", 1);
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}
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break;
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case PERM_TIMESTAMP:
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if (seteuid(timestamp_uid))
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fatal("seteuid(timestamp_uid)", 1);
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break;
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}
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}
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# endif /* HAVE_SETREUID */
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#endif /* HAVE_SETRESUID */
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static void
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runas_setup()
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{
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#ifdef HAVE_LOGIN_CAP_H
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int error, flags;
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extern login_cap_t *lc;
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#endif
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if (runas_pw->pw_name != NULL) {
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#ifdef HAVE_PAM
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pam_prep_user(runas_pw);
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#endif /* HAVE_PAM */
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#ifdef HAVE_LOGIN_CAP_H
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if (def_flag(I_USE_LOGINCLASS)) {
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/*
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* We don't have setusercontext() set the user since we
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* may only want to set the effective uid. Depending on
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* sudoers and/or command line arguments we may not want
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* setusercontext() to call initgroups().
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*/
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flags = LOGIN_SETRESOURCES|LOGIN_SETPRIORITY;
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if (!def_flag(I_PRESERVE_GROUPS))
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flags |= LOGIN_SETGROUP;
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else if (setgid(runas_pw->pw_gid))
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perror("cannot set gid to runas gid");
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error = setusercontext(lc, runas_pw,
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runas_pw->pw_uid, flags);
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if (error) {
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if (runas_pw->pw_gid != 0)
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fatal("unable to set user context", 1);
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else
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perror("unable to set user context");
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}
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} else
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#endif /* HAVE_LOGIN_CAP_H */
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{
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if (setgid(runas_pw->pw_gid))
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perror("cannot set gid to runas gid");
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#ifdef HAVE_INITGROUPS
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/*
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* Initialize group vector unless asked not to.
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*/
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if (!def_flag(I_PRESERVE_GROUPS) &&
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initgroups(*user_runas, runas_pw->pw_gid) < 0)
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perror("cannot set group vector");
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#endif /* HAVE_INITGROUPS */
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}
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}
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}
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static void
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fatal(str, printerr)
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char *str;
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{
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if (str) {
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if (printerr)
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perror(str);
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else {
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fputs(str, stderr);
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fputc('\n', stderr);
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}
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}
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exit(1);
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}
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