1/*-
2 * Copyright (c) 2011 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Edward Tomasz Napierala under sponsorship
6 * from the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: head/sys/kern/kern_loginclass.c 219304 2011-03-05 12:40:35Z trasz $
30 */
31
32/*
33 * Processes may set login class name using setloginclass(2). This
34 * is usually done through call to setusercontext(3), by programs
35 * such as login(1), based on information from master.passwd(5). Kernel
36 * uses this information to enforce per-class resource limits. Current
37 * login class can be determined using id(1). Login class is inherited
38 * from the parent process during fork(2). If not set, it defaults
39 * to "default".
40 *
41 * Code in this file implements setloginclass(2) and getloginclass(2)
42 * system calls, and maintains class name storage and retrieval.
43 */
44
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD: head/sys/kern/kern_loginclass.c 219304 2011-03-05 12:40:35Z trasz $");
47
48#include <sys/param.h>
49#include <sys/eventhandler.h>
50#include <sys/kernel.h>
51#include <sys/lock.h>
52#include <sys/loginclass.h>
53#include <sys/malloc.h>
54#include <sys/mutex.h>
55#include <sys/types.h>
56#include <sys/priv.h>
57#include <sys/proc.h>
58#include <sys/queue.h>
59#include <sys/refcount.h>
60#include <sys/sysproto.h>
61#include <sys/systm.h>
62
63static MALLOC_DEFINE(M_LOGINCLASS, "loginclass", "loginclass structures");
64
65LIST_HEAD(, loginclass) loginclasses;
66
67/*
68 * Lock protecting loginclasses list.
69 */
70static struct mtx loginclasses_lock;
71
72static void lc_init(void);
73SYSINIT(loginclass, SI_SUB_CPU, SI_ORDER_FIRST, lc_init, NULL);
74
75void
76loginclass_hold(struct loginclass *lc)
77{
78
79 refcount_acquire(&lc->lc_refcount);
80}
81
82void
83loginclass_free(struct loginclass *lc)
84{
85 int old;
86
87 old = lc->lc_refcount;
88 if (old > 1 && atomic_cmpset_int(&lc->lc_refcount, old, old - 1))
89 return;
90
91 mtx_lock(&loginclasses_lock);
92 if (refcount_release(&lc->lc_refcount)) {
93 LIST_REMOVE(lc, lc_next);
94 mtx_unlock(&loginclasses_lock);
95 free(lc, M_LOGINCLASS);
96
97 return;
98 }
99 mtx_unlock(&loginclasses_lock);
100}
101
102/*
103 * Return loginclass structure with a corresponding name. Not
104 * performance critical, as it's used mainly by setloginclass(2),
105 * which happens once per login session. Caller has to use
106 * loginclass_free() on the returned value when it's no longer
107 * needed.
108 */
109struct loginclass *
110loginclass_find(const char *name)
111{
112 struct loginclass *lc, *newlc;
113
114 if (name[0] == '\0' || strlen(name) >= MAXLOGNAME)
115 return (NULL);
116
117 newlc = malloc(sizeof(*newlc), M_LOGINCLASS, M_ZERO | M_WAITOK);
118
119 mtx_lock(&loginclasses_lock);
120 LIST_FOREACH(lc, &loginclasses, lc_next) {
121 if (strcmp(name, lc->lc_name) != 0)
122 continue;
123
124 /* Found loginclass with a matching name? */
125 loginclass_hold(lc);
126 mtx_unlock(&loginclasses_lock);
127 free(newlc, M_LOGINCLASS);
128 return (lc);
129 }
130
131 /* Add new loginclass. */
132 strcpy(newlc->lc_name, name);
133 refcount_init(&newlc->lc_refcount, 1);
134 LIST_INSERT_HEAD(&loginclasses, newlc, lc_next);
135 mtx_unlock(&loginclasses_lock);
136
137 return (newlc);
138}
139
140/*
141 * Get login class name.
142 */
143#ifndef _SYS_SYSPROTO_H_
144struct getloginclass_args {
145 char *namebuf;
146 size_t namelen;
147};
148#endif
149/* ARGSUSED */
150int
151getloginclass(struct thread *td, struct getloginclass_args *uap)
152{
153 int error = 0;
154 size_t lcnamelen;
155 struct proc *p;
156 struct loginclass *lc;
157
158 p = td->td_proc;
159 PROC_LOCK(p);
160 lc = p->p_ucred->cr_loginclass;
161 loginclass_hold(lc);
162 PROC_UNLOCK(p);
163
164 lcnamelen = strlen(lc->lc_name) + 1;
165 if (lcnamelen > uap->namelen)
166 error = ERANGE;
167 if (error == 0)
168 error = copyout(lc->lc_name, uap->namebuf, lcnamelen);
169 loginclass_free(lc);
170 return (error);
171}
172
173/*
174 * Set login class name.
175 */
176#ifndef _SYS_SYSPROTO_H_
177struct setloginclass_args {
178 const char *namebuf;
179};
180#endif
181/* ARGSUSED */
182int
183setloginclass(struct thread *td, struct setloginclass_args *uap)
184{
185 struct proc *p = td->td_proc;
186 int error;
187 char lcname[MAXLOGNAME];
188 struct loginclass *newlc;
189 struct ucred *newcred, *oldcred;
190
191 error = priv_check(td, PRIV_PROC_SETLOGINCLASS);
192 if (error != 0)
193 return (error);
194 error = copyinstr(uap->namebuf, lcname, sizeof(lcname), NULL);
195 if (error != 0)
196 return (error);
197
198 newlc = loginclass_find(lcname);
199 if (newlc == NULL)
200 return (EINVAL);
201 newcred = crget();
202
203 PROC_LOCK(p);
204 oldcred = crcopysafe(p, newcred);
205 newcred->cr_loginclass = newlc;
206 p->p_ucred = newcred;
207 PROC_UNLOCK(p);
208
209 loginclass_free(oldcred->cr_loginclass);
210 crfree(oldcred);
211
212 return (0);
213}
214
215static void
216lc_init(void)
217{
218
219 mtx_init(&loginclasses_lock, "loginclasses lock", NULL, MTX_DEF);
220}