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Diffstat (limited to 'usr.bin/at/privs.c')
| -rw-r--r-- | usr.bin/at/privs.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/usr.bin/at/privs.c b/usr.bin/at/privs.c new file mode 100644 index 0000000..1b7e12d --- /dev/null +++ b/usr.bin/at/privs.c @@ -0,0 +1,104 @@ +/* $NetBSD: privs.c,v 1.3 2018/02/25 23:48:16 htodd Exp $ */ + +/* + * privs.c - privileged operations + * Copyright (C) 1993 Thomas Koenig + * + * 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. The name of the author(s) may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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(S) 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, WETHER 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. + * + * From: OpenBSD: privs.h,v 1.4 1997/03/01 23:40:12 millert Exp + */ + +#include <unistd.h> + +#include "privs.h" + +/* + * Used by: usr.bin/at + * Used by: libexec/atrun + */ + +/* + * Relinquish privileges temporarily for a setuid or setgid program + * with the option of getting them back later. This is done by + * using POSIX saved user and groups ids. Call RELINQUISH_PRIVS once + * at the beginning of the main program. This will cause all operations + * to be executed with the real userid. When you need the privileges + * of the setuid/setgid invocation, call PRIV_START; when you no longer + * need it, call PRIV_END. Note that it is an error to call PRIV_START + * and not PRIV_END within the same function. + * + * Use RELINQUISH_PRIVS_ROOT(a,b) if your program started out running + * as root, and you want to drop back the effective userid to a + * and the effective group id to b, with the option to get them back + * later. + * + * Problems: Do not use return between PRIV_START and PRIV_END; this + * will cause the program to continue running in an unprivileged + * state. + * + * It is NOT safe to call exec(), system() or popen() with a user- + * supplied program (i.e. without carefully checking PATH and any + * library load paths) with relinquished privileges; the called program + * can acquire them just as easily. Set both effective and real userid + * to the real userid before calling any of them. + */ + +uid_t real_uid, effective_uid; +gid_t real_gid, effective_gid; + +void +privs_enter(void) +{ + if (seteuid(effective_uid) == -1) + privs_fail("Cannot get user privs"); + if (setegid(effective_gid) == -1) + privs_fail("Cannot get group privs"); +} + +void +privs_exit(void) +{ + if (setegid(real_gid) == -1) + privs_fail("Cannot relinquish group privs"); + if (seteuid(real_uid) == -1) + privs_fail("Cannot relinquish user privs"); +} + +void +privs_relinquish(void) +{ + real_uid = getuid(); + effective_uid = geteuid(); + real_gid = getgid(); + effective_gid = getegid(); + privs_exit(); +} + +void +privs_relinquish_root(uid_t ruid, gid_t rgid) +{ + real_uid = ruid; + real_gid = rgid; + effective_uid = geteuid(); + effective_gid = getegid(); + privs_exit(); +} |