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