1 /* $Id: platform.c,v 1.22 2014/07/18 04:11:26 djm Exp $ */
2
3 /*
4 * Copyright (c) 2006 Darren Tucker. All rights reserved.
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include "includes.h"
20
21 #include <sys/types.h>
22
23 #include <stdarg.h>
24 #include <unistd.h>
25
26 #include "log.h"
27 #include "buffer.h"
28 #include "misc.h"
29 #include "servconf.h"
30 #include "key.h"
31 #include "hostfile.h"
32 #include "auth.h"
33 #include "auth-pam.h"
34 #include "platform.h"
35
36 #include "openbsd-compat/openbsd-compat.h"
37
38 extern int use_privsep;
39 extern ServerOptions options;
40
41 void
platform_pre_listen(void)42 platform_pre_listen(void)
43 {
44 #ifdef LINUX_OOM_ADJUST
45 /* Adjust out-of-memory killer so listening process is not killed */
46 oom_adjust_setup();
47 #endif
48 }
49
50 void
platform_pre_fork(void)51 platform_pre_fork(void)
52 {
53 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
54 solaris_contract_pre_fork();
55 #endif
56 }
57
58 void
platform_pre_restart(void)59 platform_pre_restart(void)
60 {
61 #ifdef LINUX_OOM_ADJUST
62 oom_adjust_restore();
63 #endif
64 }
65
66 void
platform_post_fork_parent(pid_t child_pid)67 platform_post_fork_parent(pid_t child_pid)
68 {
69 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
70 solaris_contract_post_fork_parent(child_pid);
71 #endif
72 }
73
74 void
platform_post_fork_child(void)75 platform_post_fork_child(void)
76 {
77 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
78 solaris_contract_post_fork_child();
79 #endif
80 #ifdef LINUX_OOM_ADJUST
81 oom_adjust_restore();
82 #endif
83 }
84
85 /* return 1 if we are running with privilege to swap UIDs, 0 otherwise */
86 int
platform_privileged_uidswap(void)87 platform_privileged_uidswap(void)
88 {
89 #ifdef HAVE_CYGWIN
90 /* uid 0 is not special on Cygwin so always try */
91 return 1;
92 #else
93 return (getuid() == 0 || geteuid() == 0);
94 #endif
95 }
96
97 /*
98 * This gets called before switching UIDs, and is called even when sshd is
99 * not running as root.
100 */
101 void
platform_setusercontext(struct passwd * pw)102 platform_setusercontext(struct passwd *pw)
103 {
104 #ifdef WITH_SELINUX
105 /* Cache selinux status for later use */
106 (void)ssh_selinux_enabled();
107 #endif
108
109 #ifdef USE_SOLARIS_PROJECTS
110 /* if solaris projects were detected, set the default now */
111 if (getuid() == 0 || geteuid() == 0)
112 solaris_set_default_project(pw);
113 #endif
114
115 #if defined(HAVE_LOGIN_CAP) && defined (__bsdi__)
116 if (getuid() == 0 || geteuid() == 0)
117 setpgid(0, 0);
118 # endif
119
120 #if defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
121 /*
122 * If we have both LOGIN_CAP and PAM, we want to establish creds
123 * before calling setusercontext (in session.c:do_setusercontext).
124 */
125 if (getuid() == 0 || geteuid() == 0) {
126 if (options.use_pam) {
127 do_pam_setcred(use_privsep);
128 }
129 }
130 # endif /* USE_PAM */
131
132 #if !defined(HAVE_LOGIN_CAP) && defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
133 if (getuid() == 0 || geteuid() == 0) {
134 /* Sets login uid for accounting */
135 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
136 error("setluid: %s", strerror(errno));
137 }
138 #endif
139 }
140
141 /*
142 * This gets called after we've established the user's groups, and is only
143 * called if sshd is running as root.
144 */
145 void
platform_setusercontext_post_groups(struct passwd * pw)146 platform_setusercontext_post_groups(struct passwd *pw)
147 {
148 #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
149 /*
150 * PAM credentials may take the form of supplementary groups.
151 * These will have been wiped by the above initgroups() call.
152 * Reestablish them here.
153 */
154 if (options.use_pam) {
155 do_pam_setcred(use_privsep);
156 }
157 #endif /* USE_PAM */
158
159 #if !defined(HAVE_LOGIN_CAP) && (defined(WITH_IRIX_PROJECT) || \
160 defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY))
161 irix_setusercontext(pw);
162 #endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
163
164 #ifdef _AIX
165 aix_usrinfo(pw);
166 #endif /* _AIX */
167
168 #ifdef HAVE_SETPCRED
169 /*
170 * If we have a chroot directory, we set all creds except real
171 * uid which we will need for chroot. If we don't have a
172 * chroot directory, we don't override anything.
173 */
174 {
175 char **creds = NULL, *chroot_creds[] =
176 { "REAL_USER=root", NULL };
177
178 if (options.chroot_directory != NULL &&
179 strcasecmp(options.chroot_directory, "none") != 0)
180 creds = chroot_creds;
181
182 if (setpcred(pw->pw_name, creds) == -1)
183 fatal("Failed to set process credentials");
184 }
185 #endif /* HAVE_SETPCRED */
186 #ifdef WITH_SELINUX
187 ssh_selinux_setup_exec_context(pw->pw_name);
188 #endif
189 }
190
191 char *
platform_krb5_get_principal_name(const char * pw_name)192 platform_krb5_get_principal_name(const char *pw_name)
193 {
194 #ifdef USE_AIX_KRB_NAME
195 return aix_krb5_get_principal_name(pw_name);
196 #else
197 return NULL;
198 #endif
199 }
200
201 /*
202 * return 1 if the specified uid is a uid that may own a system directory
203 * otherwise 0.
204 */
205 int
platform_sys_dir_uid(uid_t uid)206 platform_sys_dir_uid(uid_t uid)
207 {
208 if (uid == 0)
209 return 1;
210 #ifdef PLATFORM_SYS_DIR_UID
211 if (uid == PLATFORM_SYS_DIR_UID)
212 return 1;
213 #endif
214 return 0;
215 }
216