1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/param.h> 29 #include <sys/types.h> 30 #include <sys/sysmacros.h> 31 #include <sys/systm.h> 32 #include <sys/cred_impl.h> 33 #include <sys/errno.h> 34 #include <sys/proc.h> 35 #include <sys/priv_impl.h> 36 #include <sys/policy.h> 37 #include <sys/ddi.h> 38 #include <sys/thread.h> 39 #include <c2/audit.h> 40 41 /* 42 * System call support for manipulating privileges. 43 * 44 * 45 * setppriv(2) - set process privilege set 46 * getppriv(2) - get process privilege set 47 * getprivimplinfo(2) - get process privilege implementation information 48 * setpflags(2) - set process (privilege) flags 49 * getpflags(2) - get process (privilege) flags 50 */ 51 52 /* 53 * setppriv (priv_op_t, priv_ptype_t, priv_set_t) 54 */ 55 static int 56 setppriv(priv_op_t op, priv_ptype_t type, priv_set_t *in_pset) 57 { 58 priv_set_t pset, *target; 59 cred_t *cr, *pcr; 60 proc_t *p; 61 boolean_t donocd; 62 63 if (!PRIV_VALIDSET(type) || !PRIV_VALIDOP(op)) 64 return (set_errno(EINVAL)); 65 66 if (copyin(in_pset, &pset, sizeof (priv_set_t))) 67 return (set_errno(EFAULT)); 68 69 p = ttoproc(curthread); 70 cr = cralloc(); 71 mutex_enter(&p->p_crlock); 72 73 pcr = p->p_cred; 74 75 if (audit_active) 76 audit_setppriv(op, type, &pset, pcr); 77 78 /* 79 * Filter out unallowed request (bad op and bad type) 80 */ 81 switch (op) { 82 case PRIV_ON: 83 case PRIV_SET: 84 /* 85 * Turning on privileges; the limit set cannot grow, 86 * other sets can but only as long as they remain subsets 87 * of P. Only immediately after exec holds that P <= L. 88 */ 89 if (((type == PRIV_LIMIT && 90 !priv_issubset(&pset, &CR_LPRIV(pcr))) || 91 !priv_issubset(&pset, &CR_OPPRIV(pcr))) && 92 !priv_issubset(&pset, priv_getset(pcr, type))) { 93 mutex_exit(&p->p_crlock); 94 crfree(cr); 95 return (set_errno(EPERM)); 96 } 97 break; 98 99 case PRIV_OFF: 100 /* PRIV_OFF is always allowed */ 101 break; 102 } 103 104 /* 105 * OK! everything is cool. 106 * Do cred COW. 107 */ 108 crcopy_to(pcr, cr); 109 110 /* 111 * If we change the effective, permitted or limit set, we attain 112 * "privilege awareness". 113 */ 114 if (type != PRIV_INHERITABLE) 115 priv_set_PA(cr); 116 117 target = &(CR_PRIVS(cr)->crprivs[type]); 118 119 switch (op) { 120 case PRIV_ON: 121 priv_union(&pset, target); 122 break; 123 case PRIV_OFF: 124 priv_inverse(&pset); 125 priv_intersect(target, &pset); 126 127 /* 128 * Fall-thru to set target and change other process 129 * privilege sets. 130 */ 131 /*FALLTHRU*/ 132 133 case PRIV_SET: 134 *target = pset; 135 136 /* 137 * Take privileges no longer permitted out 138 * of other effective sets as well. 139 * Limit set is enforced at exec() time. 140 */ 141 if (type == PRIV_PERMITTED) 142 priv_intersect(&pset, &CR_EPRIV(cr)); 143 break; 144 } 145 146 /* 147 * When we give up privileges not in the inheritable set, 148 * set SNOCD if not already set; first we compute the 149 * privileges removed from P using Diff = (~P') & P 150 * and then we check whether the removed privileges are 151 * a subset of I. If we retain uid 0, all privileges 152 * are required anyway so don't set SNOCD. 153 */ 154 if (type == PRIV_PERMITTED && (p->p_flag & SNOCD) == 0 && 155 cr->cr_uid != 0 && cr->cr_ruid != 0 && cr->cr_suid != 0) { 156 priv_set_t diff = CR_OPPRIV(cr); 157 priv_inverse(&diff); 158 priv_intersect(&CR_OPPRIV(pcr), &diff); 159 donocd = !priv_issubset(&diff, &CR_IPRIV(cr)); 160 } else { 161 donocd = B_FALSE; 162 } 163 164 p->p_cred = cr; 165 mutex_exit(&p->p_crlock); 166 167 if (donocd) { 168 mutex_enter(&p->p_lock); 169 p->p_flag |= SNOCD; 170 mutex_exit(&p->p_lock); 171 } 172 173 crset(p, cr); /* broadcast to process threads */ 174 175 return (0); 176 } 177 178 /* 179 * getppriv (priv_ptype_t, priv_set_t *) 180 */ 181 static int 182 getppriv(priv_ptype_t type, priv_set_t *pset) 183 { 184 if (!PRIV_VALIDSET(type)) 185 return (set_errno(EINVAL)); 186 187 if (copyout(priv_getset(CRED(), type), pset, sizeof (priv_set_t)) != 0) 188 return (set_errno(EFAULT)); 189 190 return (0); 191 } 192 193 static int 194 getprivimplinfo(void *buf, size_t bufsize) 195 { 196 int err; 197 198 err = copyout(priv_hold_implinfo(), buf, min(bufsize, privinfosize)); 199 200 priv_release_implinfo(); 201 202 if (err) 203 return (set_errno(EFAULT)); 204 205 return (0); 206 } 207 208 /* 209 * Set process flags in the given target cred. If NULL is specified, then 210 * CRED() is used; otherwise the cred is assumed to be modifiable (i.e. newly 211 * crdup'ed, or equivalent). Some flags are set in the proc rather than cred; 212 * for these, curproc is always used. 213 * 214 * For now we cheat: the flags are actually bit masks so we can simplify 215 * some; we do make sure that the arguments are valid, though. 216 */ 217 218 int 219 setpflags(uint_t flag, uint_t val, cred_t *tcr) 220 { 221 cred_t *cr, *pcr; 222 proc_t *p = curproc; 223 uint_t newflags; 224 boolean_t use_curcred = (tcr == NULL); 225 226 if (val > 1 || (flag != PRIV_DEBUG && flag != PRIV_AWARE && 227 flag != NET_MAC_AWARE && flag != NET_MAC_AWARE_INHERIT && 228 flag != __PROC_PROTECT)) { 229 return (EINVAL); 230 } 231 232 if (flag == __PROC_PROTECT) { 233 mutex_enter(&p->p_lock); 234 if (val == 0) 235 p->p_flag &= ~SNOCD; 236 else 237 p->p_flag |= SNOCD; 238 mutex_exit(&p->p_lock); 239 return (0); 240 } 241 242 if (use_curcred) { 243 cr = cralloc(); 244 mutex_enter(&p->p_crlock); 245 pcr = p->p_cred; 246 } else { 247 cr = pcr = tcr; 248 } 249 250 newflags = CR_FLAGS(pcr); 251 252 if (val != 0) 253 newflags |= flag; 254 else 255 newflags &= ~flag; 256 257 /* No change */ 258 if (CR_FLAGS(pcr) == newflags) { 259 if (use_curcred) { 260 mutex_exit(&p->p_crlock); 261 crfree(cr); 262 } 263 return (0); 264 } 265 266 /* 267 * Setting either the NET_MAC_AWARE or NET_MAC_AWARE_INHERIT 268 * flags is a restricted operation. 269 * 270 * When invoked via the PRIVSYS_SETPFLAGS syscall 271 * we require that the current cred has the net_mac_aware 272 * privilege in its effective set. 273 * 274 * When called from within the kernel by label-aware 275 * services such as NFS, we don't require a privilege check. 276 * 277 */ 278 if ((flag == NET_MAC_AWARE || flag == NET_MAC_AWARE_INHERIT) && 279 (val == 1) && use_curcred) { 280 if (secpolicy_net_mac_aware(pcr) != 0) { 281 mutex_exit(&p->p_crlock); 282 crfree(cr); 283 return (EPERM); 284 } 285 } 286 287 /* Trying to unset PA; if we can't, return an error */ 288 if (flag == PRIV_AWARE && val == 0 && !priv_can_clear_PA(pcr)) { 289 if (use_curcred) { 290 mutex_exit(&p->p_crlock); 291 crfree(cr); 292 } 293 return (EPERM); 294 } 295 296 /* Committed to changing the flag */ 297 if (use_curcred) 298 crcopy_to(pcr, cr); 299 if (flag == PRIV_AWARE) { 300 if (val != 0) 301 priv_set_PA(cr); 302 else 303 priv_adjust_PA(cr); 304 } else { 305 CR_FLAGS(cr) = newflags; 306 } 307 308 if (use_curcred) { 309 p->p_cred = cr; 310 mutex_exit(&p->p_crlock); 311 crset(p, cr); 312 } 313 314 return (0); 315 } 316 317 /* 318 * Getpflags. Currently only implements single bit flags. 319 */ 320 uint_t 321 getpflags(uint_t flag, const cred_t *cr) 322 { 323 if (flag != PRIV_DEBUG && flag != PRIV_AWARE && 324 flag != NET_MAC_AWARE && flag != NET_MAC_AWARE_INHERIT) 325 return ((uint_t)-1); 326 327 return ((CR_FLAGS(cr) & flag) != 0); 328 } 329 330 /* 331 * Privilege system call entry point 332 */ 333 int 334 privsys(int code, priv_op_t op, priv_ptype_t type, void *buf, size_t bufsize) 335 { 336 int retv; 337 extern int issetugid(void); 338 339 switch (code) { 340 case PRIVSYS_SETPPRIV: 341 if (bufsize < sizeof (priv_set_t)) 342 return (set_errno(ENOMEM)); 343 return (setppriv(op, type, buf)); 344 case PRIVSYS_GETPPRIV: 345 if (bufsize < sizeof (priv_set_t)) 346 return (set_errno(ENOMEM)); 347 return (getppriv(type, buf)); 348 case PRIVSYS_GETIMPLINFO: 349 return (getprivimplinfo(buf, bufsize)); 350 case PRIVSYS_SETPFLAGS: 351 retv = setpflags((uint_t)op, (uint_t)type, NULL); 352 return (retv != 0 ? set_errno(retv) : 0); 353 case PRIVSYS_GETPFLAGS: 354 retv = (int)getpflags((uint_t)op, CRED()); 355 return (retv == -1 ? set_errno(EINVAL) : retv); 356 case PRIVSYS_ISSETUGID: 357 return (issetugid()); 358 } 359 return (set_errno(EINVAL)); 360 } 361 362 #ifdef _SYSCALL32_IMPL 363 int 364 privsys32(int code, priv_op_t op, priv_ptype_t type, caddr32_t *buf, 365 size32_t bufsize) 366 { 367 return (privsys(code, op, type, (void *)buf, (size_t)bufsize)); 368 } 369 #endif 370