1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1999-2001, 2008 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 /* 29 * Support functionality for the POSIX.1e ACL interface 30 * These calls are intended only to be called within the library. 31 */ 32 33 #include <sys/cdefs.h> 34 #if 0 35 __FBSDID("$FreeBSD: head/lib/libc/posix1e/acl_support.c 326193 2017-11-25 17:12:48Z pfg $"); 36 #else 37 __RCSID("$NetBSD: acl_support.c,v 1.1 2020/05/16 18:31:47 christos Exp $"); 38 #endif 39 40 #include "namespace.h" 41 #include <sys/types.h> 42 #include <sys/acl.h> 43 #include <errno.h> 44 #include <grp.h> 45 #include <pwd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <assert.h> 50 51 #include "acl_support.h" 52 53 #define ACL_STRING_PERM_WRITE 'w' 54 #define ACL_STRING_PERM_READ 'r' 55 #define ACL_STRING_PERM_EXEC 'x' 56 #define ACL_STRING_PERM_NONE '-' 57 58 /* 59 * Return 0, if both ACLs are identical. 60 */ 61 int 62 _acl_differs(const acl_t a, const acl_t b) 63 { 64 size_t i; 65 struct acl_entry *entrya, *entryb; 66 67 assert(_acl_brand(a) == _acl_brand(b)); 68 assert(_acl_brand(a) != ACL_BRAND_UNKNOWN); 69 assert(_acl_brand(b) != ACL_BRAND_UNKNOWN); 70 71 if (a->ats_acl.acl_cnt != b->ats_acl.acl_cnt) 72 return (1); 73 74 for (i = 0; i < b->ats_acl.acl_cnt; i++) { 75 entrya = &(a->ats_acl.acl_entry[i]); 76 entryb = &(b->ats_acl.acl_entry[i]); 77 78 if (entrya->ae_tag != entryb->ae_tag || 79 entrya->ae_id != entryb->ae_id || 80 entrya->ae_perm != entryb->ae_perm || 81 entrya->ae_entry_type != entryb->ae_entry_type || 82 entrya->ae_flags != entryb->ae_flags) 83 return (1); 84 } 85 86 return (0); 87 } 88 89 /* 90 * _posix1e_acl_entry_compare -- compare two acl_entry structures to 91 * determine the order they should appear in. Used by _posix1e_acl_sort to 92 * sort ACL entries into the kernel-desired order -- i.e., the order useful 93 * for evaluation and O(n) validity checking. Beter to have an O(nlogn) sort 94 * in userland and an O(n) in kernel than to have both in kernel. 95 */ 96 typedef int (*compare)(const void *, const void *); 97 static int 98 _posix1e_acl_entry_compare(struct acl_entry *a, struct acl_entry *b) 99 { 100 101 assert(_entry_brand(a) == ACL_BRAND_POSIX); 102 assert(_entry_brand(b) == ACL_BRAND_POSIX); 103 104 /* 105 * First, sort between tags -- conveniently defined in the correct 106 * order for verification. 107 */ 108 if (a->ae_tag < b->ae_tag) 109 return (-1); 110 if (a->ae_tag > b->ae_tag) 111 return (1); 112 113 /* 114 * Next compare uids/gids on appropriate types. 115 */ 116 117 if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) { 118 if (a->ae_id < b->ae_id) 119 return (-1); 120 if (a->ae_id > b->ae_id) 121 return (1); 122 123 /* shouldn't be equal, fall through to the invalid case */ 124 } 125 126 /* 127 * Don't know how to sort multiple entries of the rest--either it's 128 * a bad entry, or there shouldn't be more than one. Ignore and the 129 * validity checker can get it later. 130 */ 131 return (0); 132 } 133 134 /* 135 * _posix1e_acl_sort -- sort ACL entries in POSIX.1e-formatted ACLs. 136 */ 137 void 138 _posix1e_acl_sort(acl_t acl) 139 { 140 struct acl *acl_int; 141 142 acl_int = &acl->ats_acl; 143 144 qsort(&acl_int->acl_entry[0], acl_int->acl_cnt, 145 sizeof(struct acl_entry), (compare) _posix1e_acl_entry_compare); 146 } 147 148 /* 149 * acl_posix1e -- in what situations should we acl_sort before submission? 150 * We apply posix1e ACL semantics for any ACL of type ACL_TYPE_ACCESS or 151 * ACL_TYPE_DEFAULT 152 */ 153 int 154 _posix1e_acl(acl_t acl, acl_type_t type) 155 { 156 157 if (_acl_brand(acl) != ACL_BRAND_POSIX) 158 return (0); 159 160 return ((type == ACL_TYPE_ACCESS) || (type == ACL_TYPE_DEFAULT)); 161 } 162 163 /* 164 * _posix1e_acl_check -- given an ACL, check its validity. This is mirrored 165 * from code in sys/kern/kern_acl.c, and if changes are made in one, they 166 * should be made in the other also. This copy of acl_check is made 167 * available * in userland for the benefit of processes wanting to check ACLs 168 * for validity before submitting them to the kernel, or for performing 169 * in userland file system checking. Needless to say, the kernel makes 170 * the real checks on calls to get/setacl. 171 * 172 * See the comments in kernel for explanation -- just briefly, it assumes 173 * an already sorted ACL, and checks based on that assumption. The 174 * POSIX.1e interface, acl_valid(), will perform the sort before calling 175 * this. Returns 0 on success, EINVAL on failure. 176 */ 177 int 178 _posix1e_acl_check(acl_t acl) 179 { 180 struct acl *acl_int; 181 struct acl_entry *entry; /* current entry */ 182 uid_t highest_uid=0, highest_gid=0; 183 int stage = ACL_USER_OBJ; 184 size_t i = 0; 185 int count_user_obj=0, count_user=0, count_group_obj=0, 186 count_group=0, count_mask=0, count_other=0; 187 188 acl_int = &acl->ats_acl; 189 190 /* printf("_posix1e_acl_check: checking acl with %d entries\n", 191 acl->acl_cnt); */ 192 while (i < acl_int->acl_cnt) { 193 entry = &acl_int->acl_entry[i]; 194 195 if ((entry->ae_perm | ACL_PERM_BITS) != ACL_PERM_BITS) 196 return (EINVAL); 197 198 switch(entry->ae_tag) { 199 case ACL_USER_OBJ: 200 /* printf("_posix1e_acl_check: %d: ACL_USER_OBJ\n", 201 i); */ 202 if (stage > ACL_USER_OBJ) 203 return (EINVAL); 204 stage = ACL_USER; 205 count_user_obj++; 206 break; 207 208 case ACL_USER: 209 /* printf("_posix1e_acl_check: %d: ACL_USER\n", i); */ 210 if (stage > ACL_USER) 211 return (EINVAL); 212 stage = ACL_USER; 213 if (count_user && (entry->ae_id <= highest_uid)) 214 return (EINVAL); 215 highest_uid = entry->ae_id; 216 count_user++; 217 break; 218 219 case ACL_GROUP_OBJ: 220 /* printf("_posix1e_acl_check: %d: ACL_GROUP_OBJ\n", 221 i); */ 222 if (stage > ACL_GROUP_OBJ) 223 return (EINVAL); 224 stage = ACL_GROUP; 225 count_group_obj++; 226 break; 227 228 case ACL_GROUP: 229 /* printf("_posix1e_acl_check: %d: ACL_GROUP\n", i); */ 230 if (stage > ACL_GROUP) 231 return (EINVAL); 232 stage = ACL_GROUP; 233 if (count_group && (entry->ae_id <= highest_gid)) 234 return (EINVAL); 235 highest_gid = entry->ae_id; 236 count_group++; 237 break; 238 239 case ACL_MASK: 240 /* printf("_posix1e_acl_check: %d: ACL_MASK\n", i); */ 241 if (stage > ACL_MASK) 242 return (EINVAL); 243 stage = ACL_MASK; 244 count_mask++; 245 break; 246 247 case ACL_OTHER: 248 /* printf("_posix1e_acl_check: %d: ACL_OTHER\n", i); */ 249 if (stage > ACL_OTHER) 250 return (EINVAL); 251 stage = ACL_OTHER; 252 count_other++; 253 break; 254 255 default: 256 /* printf("_posix1e_acl_check: %d: INVALID\n", i); */ 257 return (EINVAL); 258 } 259 i++; 260 } 261 262 if (count_user_obj != 1) 263 return (EINVAL); 264 265 if (count_group_obj != 1) 266 return (EINVAL); 267 268 if (count_mask != 0 && count_mask != 1) 269 return (EINVAL); 270 271 if (count_other != 1) 272 return (EINVAL); 273 274 return (0); 275 } 276 277 /* 278 * Given a right-shifted permission (i.e., direct ACL_PERM_* mask), fill 279 * in a string describing the permissions. 280 */ 281 int 282 _posix1e_acl_perm_to_string(acl_perm_t perm, ssize_t buf_len, char *buf) 283 { 284 285 if (buf_len < _POSIX1E_ACL_STRING_PERM_MAXSIZE + 1) { 286 errno = ENOMEM; 287 return (-1); 288 } 289 290 if ((perm | ACL_PERM_BITS) != ACL_PERM_BITS) { 291 errno = EINVAL; 292 return (-1); 293 } 294 295 buf[3] = 0; /* null terminate */ 296 297 if (perm & ACL_READ) 298 buf[0] = ACL_STRING_PERM_READ; 299 else 300 buf[0] = ACL_STRING_PERM_NONE; 301 302 if (perm & ACL_WRITE) 303 buf[1] = ACL_STRING_PERM_WRITE; 304 else 305 buf[1] = ACL_STRING_PERM_NONE; 306 307 if (perm & ACL_EXECUTE) 308 buf[2] = ACL_STRING_PERM_EXEC; 309 else 310 buf[2] = ACL_STRING_PERM_NONE; 311 312 return (0); 313 } 314 315 /* 316 * given a string, return a permission describing it 317 */ 318 int 319 _posix1e_acl_string_to_perm(char *string, acl_perm_t *perm) 320 { 321 acl_perm_t myperm = ACL_PERM_NONE; 322 char *ch; 323 324 ch = string; 325 while (*ch) { 326 switch(*ch) { 327 case ACL_STRING_PERM_READ: 328 myperm |= ACL_READ; 329 break; 330 case ACL_STRING_PERM_WRITE: 331 myperm |= ACL_WRITE; 332 break; 333 case ACL_STRING_PERM_EXEC: 334 myperm |= ACL_EXECUTE; 335 break; 336 case ACL_STRING_PERM_NONE: 337 break; 338 default: 339 return (EINVAL); 340 } 341 ch++; 342 } 343 344 *perm = myperm; 345 return (0); 346 } 347 348 /* 349 * Add an ACL entry without doing much checking, et al 350 */ 351 int 352 _posix1e_acl_add_entry(acl_t acl, acl_tag_t tag, uid_t id, acl_perm_t perm) 353 { 354 struct acl *acl_int; 355 struct acl_entry *e; 356 357 acl_int = &acl->ats_acl; 358 359 if (acl_int->acl_cnt >= ACL_MAX_ENTRIES) { 360 errno = ENOMEM; 361 return (-1); 362 } 363 364 e = &(acl_int->acl_entry[acl_int->acl_cnt]); 365 e->ae_perm = perm; 366 e->ae_tag = tag; 367 e->ae_id = id; 368 acl_int->acl_cnt++; 369 370 return (0); 371 } 372 373 /* 374 * Convert "old" type - ACL_TYPE_{ACCESS,DEFAULT}_OLD - into its "new" 375 * counterpart. It's necessary for the old (pre-NFSv4 ACLs) binaries 376 * to work with new libc and kernel. Fixing 'type' for old binaries with 377 * old libc and new kernel is being done by kern/vfs_acl.c:type_unold(). 378 */ 379 int 380 _acl_type_unold(acl_type_t type) 381 { 382 383 switch (type) { 384 case ACL_TYPE_ACCESS_OLD: 385 return (ACL_TYPE_ACCESS); 386 case ACL_TYPE_DEFAULT_OLD: 387 return (ACL_TYPE_DEFAULT); 388 default: 389 return (type); 390 } 391 } 392 393 char * 394 string_skip_whitespace(char *string) 395 { 396 397 while (*string && ((*string == ' ') || (*string == '\t'))) 398 string++; 399 400 return (string); 401 } 402 403 void 404 string_trim_trailing_whitespace(char *string) 405 { 406 char *end; 407 408 if (*string == '\0') 409 return; 410 411 end = string + strlen(string) - 1; 412 413 while (end != string) { 414 if ((*end == ' ') || (*end == '\t')) { 415 *end = '\0'; 416 end--; 417 } else { 418 return; 419 } 420 } 421 422 return; 423 } 424
Indexes created Sat Sep 20 22:09:52 GMT 2025