1/* $Id: platform.c,v 1.19 2013/03/12 00:31:05 dtucker 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 "servconf.h"
29#include "key.h"
30#include "hostfile.h"
31#include "auth.h"
32#include "auth-pam.h"
33#include "platform.h"
34
35#include "openbsd-compat/openbsd-compat.h"
36
37extern int use_privsep;
38extern ServerOptions options;
39
40void
41platform_pre_listen(void)
42{
43#ifdef LINUX_OOM_ADJUST
44	/* Adjust out-of-memory killer so listening process is not killed */
45	oom_adjust_setup();
46#endif
47}
48
49void
50platform_pre_fork(void)
51{
52#ifdef USE_SOLARIS_PROCESS_CONTRACTS
53	solaris_contract_pre_fork();
54#endif
55}
56
57void
58platform_post_fork_parent(pid_t child_pid)
59{
60#ifdef USE_SOLARIS_PROCESS_CONTRACTS
61	solaris_contract_post_fork_parent(child_pid);
62#endif
63}
64
65void
66platform_post_fork_child(void)
67{
68#ifdef USE_SOLARIS_PROCESS_CONTRACTS
69	solaris_contract_post_fork_child();
70#endif
71#ifdef LINUX_OOM_ADJUST
72	oom_adjust_restore();
73#endif
74}
75
76/* return 1 if we are running with privilege to swap UIDs, 0 otherwise */
77int
78platform_privileged_uidswap(void)
79{
80#ifdef HAVE_CYGWIN
81	/* uid 0 is not special on Cygwin so always try */
82	return 1;
83#else
84	return (getuid() == 0 || geteuid() == 0);
85#endif
86}
87
88/*
89 * This gets called before switching UIDs, and is called even when sshd is
90 * not running as root.
91 */
92void
93platform_setusercontext(struct passwd *pw)
94{
95#ifdef WITH_SELINUX
96	/* Cache selinux status for later use */
97	(void)ssh_selinux_enabled();
98#endif
99
100#ifdef USE_SOLARIS_PROJECTS
101	/* if solaris projects were detected, set the default now */
102	if (getuid() == 0 || geteuid() == 0)
103		solaris_set_default_project(pw);
104#endif
105
106#if defined(HAVE_LOGIN_CAP) && defined (__bsdi__)
107	if (getuid() == 0 || geteuid() == 0)
108		setpgid(0, 0);
109# endif
110
111#if defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
112	/*
113	 * If we have both LOGIN_CAP and PAM, we want to establish creds
114	 * before calling setusercontext (in session.c:do_setusercontext).
115	 */
116	if (getuid() == 0 || geteuid() == 0) {
117		if (options.use_pam) {
118			do_pam_setcred(use_privsep);
119		}
120	}
121# endif /* USE_PAM */
122
123#if !defined(HAVE_LOGIN_CAP) && defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
124	if (getuid() == 0 || geteuid() == 0) {
125		/* Sets login uid for accounting */
126		if (getluid() == -1 && setluid(pw->pw_uid) == -1)
127			error("setluid: %s", strerror(errno));
128	}
129#endif
130}
131
132/*
133 * This gets called after we've established the user's groups, and is only
134 * called if sshd is running as root.
135 */
136void
137platform_setusercontext_post_groups(struct passwd *pw)
138{
139#if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
140	/*
141	 * PAM credentials may take the form of supplementary groups.
142	 * These will have been wiped by the above initgroups() call.
143	 * Reestablish them here.
144	 */
145	if (options.use_pam) {
146		do_pam_setcred(use_privsep);
147	}
148#endif /* USE_PAM */
149
150#if !defined(HAVE_LOGIN_CAP) && (defined(WITH_IRIX_PROJECT) || \
151    defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY))
152	irix_setusercontext(pw);
153#endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
154
155#ifdef _AIX
156	aix_usrinfo(pw);
157#endif /* _AIX */
158
159#if !defined(HAVE_LOGIN_CAP) && defined(USE_LIBIAF)
160	if (set_id(pw->pw_name) != 0) {
161		exit(1);
162	}
163# endif /* USE_LIBIAF */
164
165#ifdef HAVE_SETPCRED
166	/*
167	 * If we have a chroot directory, we set all creds except real
168	 * uid which we will need for chroot.  If we don't have a
169	 * chroot directory, we don't override anything.
170	 */
171	{
172		char **creds = NULL, *chroot_creds[] =
173		    { "REAL_USER=root", NULL };
174
175		if (options.chroot_directory != NULL &&
176		    strcasecmp(options.chroot_directory, "none") != 0)
177			creds = chroot_creds;
178
179		if (setpcred(pw->pw_name, creds) == -1)
180			fatal("Failed to set process credentials");
181	}
182#endif /* HAVE_SETPCRED */
183#ifdef WITH_SELINUX
184	ssh_selinux_setup_exec_context(pw->pw_name);
185#endif
186}
187
188char *
189platform_krb5_get_principal_name(const char *pw_name)
190{
191#ifdef USE_AIX_KRB_NAME
192	return aix_krb5_get_principal_name(pw_name);
193#else
194	return NULL;
195#endif
196}
197
198/*
199 * return 1 if the specified uid is a uid that may own a system directory
200 * otherwise 0.
201 */
202int
203platform_sys_dir_uid(uid_t uid)
204{
205	if (uid == 0)
206		return 1;
207#ifdef PLATFORM_SYS_DIR_UID
208	if (uid == PLATFORM_SYS_DIR_UID)
209		return 1;
210#endif
211	return 0;
212}
213