1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2011 The FreeBSD Foundation 5 * All rights reserved. 6 * 7 * This software was developed by Edward Tomasz Napierala under sponsorship 8 * from the FreeBSD Foundation. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $FreeBSD$ 32 */ 33 34 /* 35 * Processes may set login class name using setloginclass(2). This 36 * is usually done through call to setusercontext(3), by programs 37 * such as login(1), based on information from master.passwd(5). Kernel 38 * uses this information to enforce per-class resource limits. Current 39 * login class can be determined using id(1). Login class is inherited 40 * from the parent process during fork(2). If not set, it defaults 41 * to "default". 42 * 43 * Code in this file implements setloginclass(2) and getloginclass(2) 44 * system calls, and maintains class name storage and retrieval. 45 */ 46 47 #include <sys/cdefs.h> 48 __FBSDID("$FreeBSD$"); 49 50 #include <sys/param.h> 51 #include <sys/eventhandler.h> 52 #include <sys/kernel.h> 53 #include <sys/lock.h> 54 #include <sys/loginclass.h> 55 #include <sys/malloc.h> 56 #include <sys/types.h> 57 #include <sys/priv.h> 58 #include <sys/proc.h> 59 #include <sys/queue.h> 60 #include <sys/racct.h> 61 #include <sys/rctl.h> 62 #include <sys/refcount.h> 63 #include <sys/rwlock.h> 64 #include <sys/sysproto.h> 65 #include <sys/systm.h> 66 67 static MALLOC_DEFINE(M_LOGINCLASS, "loginclass", "loginclass structures"); 68 69 LIST_HEAD(, loginclass) loginclasses; 70 71 /* 72 * Lock protecting loginclasses list. 73 */ 74 static struct rwlock loginclasses_lock; 75 RW_SYSINIT(loginclasses_init, &loginclasses_lock, "loginclasses lock"); 76 77 void 78 loginclass_hold(struct loginclass *lc) 79 { 80 81 refcount_acquire(&lc->lc_refcount); 82 } 83 84 void 85 loginclass_free(struct loginclass *lc) 86 { 87 88 if (refcount_release_if_not_last(&lc->lc_refcount)) 89 return; 90 91 rw_wlock(&loginclasses_lock); 92 if (!refcount_release(&lc->lc_refcount)) { 93 rw_wunlock(&loginclasses_lock); 94 return; 95 } 96 97 racct_destroy(&lc->lc_racct); 98 LIST_REMOVE(lc, lc_next); 99 rw_wunlock(&loginclasses_lock); 100 101 free(lc, M_LOGINCLASS); 102 } 103 104 /* 105 * Look up a loginclass struct for the parameter name. 106 * loginclasses_lock must be locked. 107 * Increase refcount on loginclass struct returned. 108 */ 109 static struct loginclass * 110 loginclass_lookup(const char *name) 111 { 112 struct loginclass *lc; 113 114 rw_assert(&loginclasses_lock, RA_LOCKED); 115 LIST_FOREACH(lc, &loginclasses, lc_next) 116 if (strcmp(name, lc->lc_name) == 0) { 117 loginclass_hold(lc); 118 break; 119 } 120 121 return (lc); 122 } 123 124 /* 125 * Return loginclass structure with a corresponding name. Not 126 * performance critical, as it's used mainly by setloginclass(2), 127 * which happens once per login session. Caller has to use 128 * loginclass_free() on the returned value when it's no longer 129 * needed. 130 */ 131 struct loginclass * 132 loginclass_find(const char *name) 133 { 134 struct loginclass *lc, *new_lc; 135 136 if (name[0] == '\0' || strlen(name) >= MAXLOGNAME) 137 return (NULL); 138 139 lc = curthread->td_ucred->cr_loginclass; 140 if (strcmp(name, lc->lc_name) == 0) { 141 loginclass_hold(lc); 142 return (lc); 143 } 144 145 rw_rlock(&loginclasses_lock); 146 lc = loginclass_lookup(name); 147 rw_runlock(&loginclasses_lock); 148 if (lc != NULL) 149 return (lc); 150 151 new_lc = malloc(sizeof(*new_lc), M_LOGINCLASS, M_ZERO | M_WAITOK); 152 racct_create(&new_lc->lc_racct); 153 refcount_init(&new_lc->lc_refcount, 1); 154 strcpy(new_lc->lc_name, name); 155 156 rw_wlock(&loginclasses_lock); 157 /* 158 * There's a chance someone created our loginclass while we 159 * were in malloc and not holding the lock, so we have to 160 * make sure we don't insert a duplicate loginclass. 161 */ 162 if ((lc = loginclass_lookup(name)) == NULL) { 163 LIST_INSERT_HEAD(&loginclasses, new_lc, lc_next); 164 rw_wunlock(&loginclasses_lock); 165 lc = new_lc; 166 } else { 167 rw_wunlock(&loginclasses_lock); 168 racct_destroy(&new_lc->lc_racct); 169 free(new_lc, M_LOGINCLASS); 170 } 171 172 return (lc); 173 } 174 175 /* 176 * Get login class name. 177 */ 178 #ifndef _SYS_SYSPROTO_H_ 179 struct getloginclass_args { 180 char *namebuf; 181 size_t namelen; 182 }; 183 #endif 184 /* ARGSUSED */ 185 int 186 sys_getloginclass(struct thread *td, struct getloginclass_args *uap) 187 { 188 struct loginclass *lc; 189 size_t lcnamelen; 190 191 lc = td->td_ucred->cr_loginclass; 192 lcnamelen = strlen(lc->lc_name) + 1; 193 if (lcnamelen > uap->namelen) 194 return (ERANGE); 195 return (copyout(lc->lc_name, uap->namebuf, lcnamelen)); 196 } 197 198 /* 199 * Set login class name. 200 */ 201 #ifndef _SYS_SYSPROTO_H_ 202 struct setloginclass_args { 203 const char *namebuf; 204 }; 205 #endif 206 /* ARGSUSED */ 207 int 208 sys_setloginclass(struct thread *td, struct setloginclass_args *uap) 209 { 210 struct proc *p = td->td_proc; 211 int error; 212 char lcname[MAXLOGNAME]; 213 struct loginclass *newlc; 214 struct ucred *newcred, *oldcred; 215 216 error = priv_check(td, PRIV_PROC_SETLOGINCLASS); 217 if (error != 0) 218 return (error); 219 error = copyinstr(uap->namebuf, lcname, sizeof(lcname), NULL); 220 if (error != 0) 221 return (error); 222 223 newlc = loginclass_find(lcname); 224 if (newlc == NULL) 225 return (EINVAL); 226 newcred = crget(); 227 228 PROC_LOCK(p); 229 oldcred = crcopysafe(p, newcred); 230 newcred->cr_loginclass = newlc; 231 proc_set_cred(p, newcred); 232 #ifdef RACCT 233 racct_proc_ucred_changed(p, oldcred, newcred); 234 crhold(newcred); 235 #endif 236 PROC_UNLOCK(p); 237 #ifdef RCTL 238 rctl_proc_ucred_changed(p, newcred); 239 crfree(newcred); 240 #endif 241 loginclass_free(oldcred->cr_loginclass); 242 crfree(oldcred); 243 244 return (0); 245 } 246 247 void 248 loginclass_racct_foreach(void (*callback)(struct racct *racct, 249 void *arg2, void *arg3), void (*pre)(void), void (*post)(void), 250 void *arg2, void *arg3) 251 { 252 struct loginclass *lc; 253 254 rw_rlock(&loginclasses_lock); 255 if (pre != NULL) 256 (pre)(); 257 LIST_FOREACH(lc, &loginclasses, lc_next) 258 (callback)(lc->lc_racct, arg2, arg3); 259 if (post != NULL) 260 (post)(); 261 rw_runlock(&loginclasses_lock); 262 } 263