masqmail

view src/permissions.c @ 221:8742d2cee364

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added a note to the long vs. int question in md5.h Solar Designer explained to me in privat conversation that the int had performed much better on some systems and that 16bit ints are very rare. Still I like using the long.
author meillo@marmaro.de
date Fri, 23 Jul 2010 10:53:04 +0200
parents ffeff2c33799
children 996b53a50f55
line source
1 /* MasqMail
2 Copyright (C) 2000 Oliver Kurth
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19 #include <pwd.h>
20 #include <grp.h>
21
22 #include "masqmail.h"
23
24 /* is there really no function in libc for this? */
25 gboolean
26 is_ingroup(uid_t uid, gid_t gid)
27 {
28 struct group *grent = getgrgid(gid);
29 struct passwd *pwent = getpwuid(uid);
30 char *entry;
31 int i = 0;
32
33 if (!grent) {
34 return FALSE;
35 }
36 if (!pwent) {
37 return FALSE;
38 }
39 /* check primary group */
40 if (pwent->pw_gid == gid) {
41 return TRUE;
42 }
43 /* check secondary groups */
44 while ((entry = grent->gr_mem[i++])) {
45 if (strcmp(pwent->pw_name, entry) == 0)
46 return TRUE;
47 }
48 return FALSE;
49 }
50
51 gboolean
52 is_privileged_user(uid_t uid)
53 {
54 /* uncomment these lines if you need the `uucp' group to be trusted too
55 struct group* grent = getgrnam("uucp");
56
57 if (is_ingroup(uid, grent->gr_gid)) {
58 return TRUE;
59 }
60 */
61
62 return (uid == 0) || (uid == conf.mail_uid) || (is_ingroup(uid, conf.mail_gid));
63 }
64
65 void
66 set_euidgid(gint uid, gint gid, uid_t * old_uid, gid_t * old_gid)
67 {
68 if (old_uid)
69 *old_uid = geteuid();
70 if (old_gid)
71 *old_gid = getegid();
72
73 seteuid(0);
74
75 if (setegid(gid) != 0) {
76 logwrite(LOG_ALERT, "could not change gid to %d: %s\n", gid, strerror(errno));
77 exit(EXIT_FAILURE);
78 }
79 if (seteuid(uid) != 0) {
80 logwrite(LOG_ALERT, "could not change uid to %d: %s\n", uid, strerror(errno));
81 exit(EXIT_FAILURE);
82 }
83 }
84
85 void
86 set_identity(uid_t old_uid, gchar * task_name)
87 {
88 if (!conf.run_as_user) {
89 if (!is_privileged_user(old_uid)) {
90 fprintf(stderr, "must be root, %s or in group %s for %s.\n", DEF_MAIL_USER, DEF_MAIL_GROUP, task_name);
91 exit(EXIT_FAILURE);
92 }
93
94 set_euidgid(conf.mail_uid, conf.mail_gid, NULL, NULL);
95 }
96 }