masqmail-0.2

view src/permissions.c @ 179:ec3fe72a3e99

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Fixed an important bug with folded headers! g_strconcat() returns a *copy* of the string, but hdr->value still pointed to the old header (which probably was a memory leak, too). If the folded part had been quite small it was likely that the new string was at the same position as the old one, thus making everything go well. But if pretty long headers were folded several times it was likely that the new string was allocated somewhere else in memory, thus breaking things. In result mails to lots of recipients (folded header) were frequently only sent to the ones in the first line. Sorry for the inconvenience.
author meillo@marmaro.de
date Fri, 03 Jun 2011 09:52:17 +0200
parents 3cbcc46c7d49
children
line source
1 /* MasqMail
2 Copyright (C) 2000 Oliver Kurth
3 Copyright (C) 2010 markus schnalke <meillo@marmaro.de>
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 */
19
20 #include <pwd.h>
21 #include <grp.h>
22
23 #include "masqmail.h"
24
25 /* is there really no function in libc for this? */
26 gboolean
27 is_ingroup(uid_t uid, gid_t gid)
28 {
29 struct group *grent = getgrgid(gid);
30 struct passwd *pwent = getpwuid(uid);
31 char *entry;
32 int i = 0;
33
34 if (!grent) {
35 return FALSE;
36 }
37 if (!pwent) {
38 return FALSE;
39 }
40 /* check primary group */
41 if (pwent->pw_gid == gid) {
42 return TRUE;
43 }
44 /* check secondary groups */
45 while ((entry = grent->gr_mem[i++])) {
46 if (strcmp(pwent->pw_name, entry) == 0)
47 return TRUE;
48 }
49 return FALSE;
50 }
51
52 gboolean
53 is_privileged_user(uid_t uid)
54 {
55 /* uncomment these lines if you need the `uucp' group to be trusted too
56 struct group* grent = getgrnam("uucp");
57
58 if (is_ingroup(uid, grent->gr_gid)) {
59 return TRUE;
60 }
61 */
62
63 return (uid == 0) || (uid == conf.mail_uid) || (is_ingroup(uid, conf.mail_gid));
64 }
65
66 void
67 set_euidgid(gint uid, gint gid, uid_t * old_uid, gid_t * old_gid)
68 {
69 if (old_uid)
70 *old_uid = geteuid();
71 if (old_gid)
72 *old_gid = getegid();
73
74 seteuid(0);
75
76 if (setegid(gid) != 0) {
77 logwrite(LOG_ALERT, "could not change gid to %d: %s\n", gid, strerror(errno));
78 exit(EXIT_FAILURE);
79 }
80 if (seteuid(uid) != 0) {
81 logwrite(LOG_ALERT, "could not change uid to %d: %s\n", uid, strerror(errno));
82 exit(EXIT_FAILURE);
83 }
84 }
85
86 void
87 set_identity(uid_t old_uid, gchar * task_name)
88 {
89 if (!conf.run_as_user) {
90 if (!is_privileged_user(old_uid)) {
91 fprintf(stderr, "must be root, %s or in group %s for %s.\n", DEF_MAIL_USER, DEF_MAIL_GROUP, task_name);
92 exit(EXIT_FAILURE);
93 }
94
95 set_euidgid(conf.mail_uid, conf.mail_gid, NULL, NULL);
96 }
97 }