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: stable/10/sys/kern/kern_loginclass.c 302229 2016-06-27 21:25:01Z bdrewery $
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: stable/10/sys/kern/kern_loginclass.c 302229 2016-06-27 21:25:01Z bdrewery $");
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/racct.h>
60 #include <sys/refcount.h>
61 #include <sys/sysproto.h>
62 #include <sys/systm.h>
63
64 static MALLOC_DEFINE(M_LOGINCLASS, "loginclass", "loginclass structures");
65
66 LIST_HEAD(, loginclass) loginclasses;
67
68 /*
69 * Lock protecting loginclasses list.
70 */
71 static struct mtx loginclasses_lock;
72 MTX_SYSINIT(loginclasses_init, &loginclasses_lock, "loginclasses lock", MTX_DEF);
73
74 void
loginclass_hold(struct loginclass * lc)75 loginclass_hold(struct loginclass *lc)
76 {
77
78 refcount_acquire(&lc->lc_refcount);
79 }
80
81 void
loginclass_free(struct loginclass * lc)82 loginclass_free(struct loginclass *lc)
83 {
84 int old;
85
86 old = lc->lc_refcount;
87 if (old > 1 && atomic_cmpset_int(&lc->lc_refcount, old, old - 1))
88 return;
89
90 mtx_lock(&loginclasses_lock);
91 if (refcount_release(&lc->lc_refcount)) {
92 racct_destroy(&lc->lc_racct);
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 */
109 struct loginclass *
loginclass_find(const char * name)110 loginclass_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 racct_create(&newlc->lc_racct);
119
120 mtx_lock(&loginclasses_lock);
121 LIST_FOREACH(lc, &loginclasses, lc_next) {
122 if (strcmp(name, lc->lc_name) != 0)
123 continue;
124
125 /* Found loginclass with a matching name? */
126 loginclass_hold(lc);
127 mtx_unlock(&loginclasses_lock);
128 racct_destroy(&newlc->lc_racct);
129 free(newlc, M_LOGINCLASS);
130 return (lc);
131 }
132
133 /* Add new loginclass. */
134 strcpy(newlc->lc_name, name);
135 refcount_init(&newlc->lc_refcount, 1);
136 LIST_INSERT_HEAD(&loginclasses, newlc, lc_next);
137 mtx_unlock(&loginclasses_lock);
138
139 return (newlc);
140 }
141
142 /*
143 * Get login class name.
144 */
145 #ifndef _SYS_SYSPROTO_H_
146 struct getloginclass_args {
147 char *namebuf;
148 size_t namelen;
149 };
150 #endif
151 /* ARGSUSED */
152 int
sys_getloginclass(struct thread * td,struct getloginclass_args * uap)153 sys_getloginclass(struct thread *td, struct getloginclass_args *uap)
154 {
155 int error = 0;
156 size_t lcnamelen;
157 struct proc *p;
158 struct loginclass *lc;
159
160 p = td->td_proc;
161 PROC_LOCK(p);
162 lc = p->p_ucred->cr_loginclass;
163 loginclass_hold(lc);
164 PROC_UNLOCK(p);
165
166 lcnamelen = strlen(lc->lc_name) + 1;
167 if (lcnamelen > uap->namelen)
168 error = ERANGE;
169 if (error == 0)
170 error = copyout(lc->lc_name, uap->namebuf, lcnamelen);
171 loginclass_free(lc);
172 return (error);
173 }
174
175 /*
176 * Set login class name.
177 */
178 #ifndef _SYS_SYSPROTO_H_
179 struct setloginclass_args {
180 const char *namebuf;
181 };
182 #endif
183 /* ARGSUSED */
184 int
sys_setloginclass(struct thread * td,struct setloginclass_args * uap)185 sys_setloginclass(struct thread *td, struct setloginclass_args *uap)
186 {
187 struct proc *p = td->td_proc;
188 int error;
189 char lcname[MAXLOGNAME];
190 struct loginclass *newlc;
191 struct ucred *newcred, *oldcred;
192
193 error = priv_check(td, PRIV_PROC_SETLOGINCLASS);
194 if (error != 0)
195 return (error);
196 error = copyinstr(uap->namebuf, lcname, sizeof(lcname), NULL);
197 if (error != 0)
198 return (error);
199
200 newlc = loginclass_find(lcname);
201 if (newlc == NULL)
202 return (EINVAL);
203 newcred = crget();
204
205 PROC_LOCK(p);
206 oldcred = crcopysafe(p, newcred);
207 newcred->cr_loginclass = newlc;
208 proc_set_cred(p, newcred);
209 PROC_UNLOCK(p);
210 #ifdef RACCT
211 racct_proc_ucred_changed(p, oldcred, newcred);
212 #endif
213 loginclass_free(oldcred->cr_loginclass);
214 crfree(oldcred);
215
216 return (0);
217 }
218
219 void
loginclass_racct_foreach(void (* callback)(struct racct * racct,void * arg2,void * arg3),void * arg2,void * arg3)220 loginclass_racct_foreach(void (*callback)(struct racct *racct,
221 void *arg2, void *arg3), void *arg2, void *arg3)
222 {
223 struct loginclass *lc;
224
225 mtx_lock(&loginclasses_lock);
226 LIST_FOREACH(lc, &loginclasses, lc_next)
227 (callback)(lc->lc_racct, arg2, arg3);
228 mtx_unlock(&loginclasses_lock);
229 }
230