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9dd887f1a6
Fixed macros for temporarily relinquishing and restoring setuid/setgid privileges so that they never change the real user and group IDs of the calling process. The setre[ug]id() calls are still used in the REDUCE_PERM macro (with the r[ug]id arguments of -1) so that the call changes the saved user and group IDs of the process to that specified. Also, the panic() and perr() functions had insufficient privileges to delete the problematic file under /var/at.
109 lines
3.5 KiB
C
109 lines
3.5 KiB
C
/*
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* privs.h - header for privileged operations
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* Copyright (C) 1993 Thomas Koenig
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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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* 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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* 2. The name of the author(s) may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _PRIVS_H
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#define _PRIVS_H
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#include <unistd.h>
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/* Relinquish privileges temporarily for a setuid or setgid program
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* with the option of getting them back later. This is done by
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* utilizing POSIX saved user and group IDs. Call RELINQUISH_PRIVS once
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* at the beginning of the main program. This will cause all operations
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* to be executed with the real userid. When you need the privileges
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* of the setuid/setgid invocation, call PRIV_START; when you no longer
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* need it, call PRIV_END. Note that it is an error to call PRIV_START
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* and not PRIV_END within the same function.
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*
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* Use RELINQUISH_PRIVS_ROOT(a,b) if your program started out running
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* as root, and you want to drop back the effective userid to a
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* and the effective group id to b, with the option to get them back
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* later.
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*
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* If you no longer need root privileges, but those of some other
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* userid/groupid, you can call REDUCE_PRIV(a,b) when your effective
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* is the user's.
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*
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* Problems: Do not use return between PRIV_START and PRIV_END; this
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* will cause the program to continue running in an unprivileged
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* state.
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*
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* It is NOT safe to call exec(), system() or popen() with a user-
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* supplied program (i.e. without carefully checking PATH and any
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* library load paths) with relinquished privileges; the called program
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* can acquire them just as easily. Set both effective and real userid
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* to the real userid before calling any of them.
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*/
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#ifndef MAIN
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extern
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#endif
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uid_t real_uid, effective_uid;
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#ifndef MAIN
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extern
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#endif
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gid_t real_gid, effective_gid;
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#define RELINQUISH_PRIVS { \
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real_uid = getuid(); \
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effective_uid = geteuid(); \
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real_gid = getgid(); \
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effective_gid = getegid(); \
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seteuid(real_uid); \
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setegid(real_gid); \
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}
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#define RELINQUISH_PRIVS_ROOT(a, b) { \
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real_uid = (a); \
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effective_uid = geteuid(); \
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real_gid = (b); \
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effective_gid = getegid(); \
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setegid(real_gid); \
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seteuid(real_uid); \
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}
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#define PRIV_START { \
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seteuid(effective_uid); \
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setegid(effective_gid); \
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}
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#define PRIV_END { \
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setegid(real_gid); \
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seteuid(real_uid); \
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}
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#define REDUCE_PRIV(a, b) { \
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PRIV_START \
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effective_uid = (a); \
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effective_gid = (b); \
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setreuid((uid_t)-1, effective_uid); \
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setregid((gid_t)-1, effective_gid); \
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PRIV_END \
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}
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#endif
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