1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2011 The FreeBSD Foundation 5 * 6 * This software was developed by Edward Tomasz Napierala under sponsorship 7 * from the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31/* 32 * Processes may set login class name using setloginclass(2). This 33 * is usually done through call to setusercontext(3), by programs 34 * such as login(1), based on information from master.passwd(5). Kernel 35 * uses this information to enforce per-class resource limits. Current 36 * login class can be determined using id(1). Login class is inherited 37 * from the parent process during fork(2). If not set, it defaults 38 * to "default". 39 * 40 * Code in this file implements setloginclass(2) and getloginclass(2) 41 * system calls, and maintains class name storage and retrieval. 42 */ 43 44#include <sys/param.h> 45#include <sys/eventhandler.h> 46#include <sys/kernel.h> 47#include <sys/lock.h> 48#include <sys/loginclass.h> 49#include <sys/malloc.h> 50#include <sys/types.h> 51#include <sys/priv.h> 52#include <sys/proc.h> 53#include <sys/queue.h> 54#include <sys/racct.h> 55#include <sys/rctl.h> 56#include <sys/refcount.h> 57#include <sys/rwlock.h> 58#include <sys/sysproto.h> 59#include <sys/systm.h> 60 61static MALLOC_DEFINE(M_LOGINCLASS, "loginclass", "loginclass structures"); 62 63LIST_HEAD(, loginclass) loginclasses; 64 65/* 66 * Lock protecting loginclasses list. 67 */ 68static struct rwlock loginclasses_lock; 69RW_SYSINIT(loginclasses_init, &loginclasses_lock, "loginclasses lock"); 70 71void 72loginclass_hold(struct loginclass *lc) 73{ 74 75 refcount_acquire(&lc->lc_refcount); 76} 77 78void 79loginclass_free(struct loginclass *lc) 80{ 81 82 if (refcount_release_if_not_last(&lc->lc_refcount)) 83 return; 84 85 rw_wlock(&loginclasses_lock); 86 if (!refcount_release(&lc->lc_refcount)) { 87 rw_wunlock(&loginclasses_lock); 88 return; 89 } 90 91 racct_destroy(&lc->lc_racct); 92 LIST_REMOVE(lc, lc_next); 93 rw_wunlock(&loginclasses_lock); 94 95 free(lc, M_LOGINCLASS); 96} 97 98/* 99 * Look up a loginclass struct for the parameter name. 100 * loginclasses_lock must be locked. 101 * Increase refcount on loginclass struct returned. 102 */ 103static struct loginclass * 104loginclass_lookup(const char *name) 105{ 106 struct loginclass *lc; 107 108 rw_assert(&loginclasses_lock, RA_LOCKED); 109 LIST_FOREACH(lc, &loginclasses, lc_next) 110 if (strcmp(name, lc->lc_name) == 0) { 111 loginclass_hold(lc); 112 break; 113 } 114 115 return (lc); 116} 117 118/* 119 * Return loginclass structure with a corresponding name. Not 120 * performance critical, as it's used mainly by setloginclass(2), 121 * which happens once per login session. Caller has to use 122 * loginclass_free() on the returned value when it's no longer 123 * needed. 124 */ 125struct loginclass * 126loginclass_find(const char *name) 127{ 128 struct loginclass *lc, *new_lc; 129 130 if (name[0] == '\0' || strlen(name) >= MAXLOGNAME) 131 return (NULL); 132 133 lc = curthread->td_ucred->cr_loginclass; 134 if (strcmp(name, lc->lc_name) == 0) { 135 loginclass_hold(lc); 136 return (lc); 137 } 138 139 rw_rlock(&loginclasses_lock); 140 lc = loginclass_lookup(name); 141 rw_runlock(&loginclasses_lock); 142 if (lc != NULL) 143 return (lc); 144 145 new_lc = malloc(sizeof(*new_lc), M_LOGINCLASS, M_ZERO | M_WAITOK); 146 racct_create(&new_lc->lc_racct); 147 refcount_init(&new_lc->lc_refcount, 1); 148 strcpy(new_lc->lc_name, name); 149 150 rw_wlock(&loginclasses_lock); 151 /* 152 * There's a chance someone created our loginclass while we 153 * were in malloc and not holding the lock, so we have to 154 * make sure we don't insert a duplicate loginclass. 155 */ 156 if ((lc = loginclass_lookup(name)) == NULL) { 157 LIST_INSERT_HEAD(&loginclasses, new_lc, lc_next); 158 rw_wunlock(&loginclasses_lock); 159 lc = new_lc; 160 } else { 161 rw_wunlock(&loginclasses_lock); 162 racct_destroy(&new_lc->lc_racct); 163 free(new_lc, M_LOGINCLASS); 164 } 165 166 return (lc); 167} 168 169/* 170 * Get login class name. 171 */ 172#ifndef _SYS_SYSPROTO_H_ 173struct getloginclass_args { 174 char *namebuf; 175 size_t namelen; 176}; 177#endif 178/* ARGSUSED */ 179int 180sys_getloginclass(struct thread *td, struct getloginclass_args *uap) 181{ 182 struct loginclass *lc; 183 size_t lcnamelen; 184 185 lc = td->td_ucred->cr_loginclass; 186 lcnamelen = strlen(lc->lc_name) + 1; 187 if (lcnamelen > uap->namelen) 188 return (ERANGE); 189 return (copyout(lc->lc_name, uap->namebuf, lcnamelen)); 190} 191 192/* 193 * Set login class name. 194 */ 195#ifndef _SYS_SYSPROTO_H_ 196struct setloginclass_args { 197 const char *namebuf; 198}; 199#endif 200/* ARGSUSED */ 201int 202sys_setloginclass(struct thread *td, struct setloginclass_args *uap) 203{ 204 struct proc *p = td->td_proc; 205 int error; 206 char lcname[MAXLOGNAME]; 207 struct loginclass *newlc; 208 struct ucred *newcred, *oldcred; 209 210 error = priv_check(td, PRIV_PROC_SETLOGINCLASS); 211 if (error != 0) 212 return (error); 213 error = copyinstr(uap->namebuf, lcname, sizeof(lcname), NULL); 214 if (error != 0) 215 return (error); 216 217 newlc = loginclass_find(lcname); 218 if (newlc == NULL) 219 return (EINVAL); 220 newcred = crget(); 221 222 PROC_LOCK(p); 223 oldcred = crcopysafe(p, newcred); 224 newcred->cr_loginclass = newlc; 225 proc_set_cred(p, newcred); 226#ifdef RACCT 227 racct_proc_ucred_changed(p, oldcred, newcred); 228 crhold(newcred); 229#endif 230 PROC_UNLOCK(p); 231#ifdef RCTL 232 rctl_proc_ucred_changed(p, newcred); 233 crfree(newcred); 234#endif 235 loginclass_free(oldcred->cr_loginclass); 236 crfree(oldcred); 237 238 return (0); 239} 240 241void 242loginclass_racct_foreach(void (*callback)(struct racct *racct, 243 void *arg2, void *arg3), void (*pre)(void), void (*post)(void), 244 void *arg2, void *arg3) 245{ 246 struct loginclass *lc; 247 248 rw_rlock(&loginclasses_lock); 249 if (pre != NULL) 250 (pre)(); 251 LIST_FOREACH(lc, &loginclasses, lc_next) 252 (callback)(lc->lc_racct, arg2, arg3); 253 if (post != NULL) 254 (post)(); 255 rw_runlock(&loginclasses_lock); 256} 257