1 /* 2 * Copyright (c) 1989, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Dave Borman at Cray Research, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "namespace.h" 40 #include <sys/types.h> 41 #include <sys/stat.h> 42 43 #include <ctype.h> 44 #include <errno.h> 45 #include <limits.h> 46 #include <signal.h> 47 #include <stddef.h> 48 #include <stdlib.h> 49 #include <unistd.h> 50 51 #ifdef SETMODE_DEBUG 52 #include <stdio.h> 53 #endif 54 #include "un-namespace.h" 55 56 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 57 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 58 59 typedef struct bitcmd { 60 char cmd; 61 char cmd2; 62 mode_t bits; 63 } BITCMD; 64 65 #define CMD2_CLR 0x01 66 #define CMD2_SET 0x02 67 #define CMD2_GBITS 0x04 68 #define CMD2_OBITS 0x08 69 #define CMD2_UBITS 0x10 70 71 static BITCMD *addcmd(BITCMD *, mode_t, mode_t, mode_t, mode_t); 72 static void compress_mode(BITCMD *); 73 #ifdef SETMODE_DEBUG 74 static void dumpmode(BITCMD *); 75 #endif 76 77 /* 78 * Given the old mode and an array of bitcmd structures, apply the operations 79 * described in the bitcmd structures to the old mode, and return the new mode. 80 * Note that there is no '=' command; a strict assignment is just a '-' (clear 81 * bits) followed by a '+' (set bits). 82 */ 83 mode_t 84 getmode(const void *bbox, mode_t omode) 85 { 86 const BITCMD *set; 87 mode_t clrval, newmode, value; 88 89 set = (const BITCMD *)bbox; 90 newmode = omode; 91 for (value = 0;; set++) 92 switch(set->cmd) { 93 /* 94 * When copying the user, group or other bits around, we "know" 95 * where the bits are in the mode so that we can do shifts to 96 * copy them around. If we don't use shifts, it gets real 97 * grundgy with lots of single bit checks and bit sets. 98 */ 99 case 'u': 100 value = (newmode & S_IRWXU) >> 6; 101 goto common; 102 103 case 'g': 104 value = (newmode & S_IRWXG) >> 3; 105 goto common; 106 107 case 'o': 108 value = newmode & S_IRWXO; 109 common: if (set->cmd2 & CMD2_CLR) { 110 clrval = 111 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 112 if (set->cmd2 & CMD2_UBITS) 113 newmode &= ~((clrval<<6) & set->bits); 114 if (set->cmd2 & CMD2_GBITS) 115 newmode &= ~((clrval<<3) & set->bits); 116 if (set->cmd2 & CMD2_OBITS) 117 newmode &= ~(clrval & set->bits); 118 } 119 if (set->cmd2 & CMD2_SET) { 120 if (set->cmd2 & CMD2_UBITS) 121 newmode |= (value<<6) & set->bits; 122 if (set->cmd2 & CMD2_GBITS) 123 newmode |= (value<<3) & set->bits; 124 if (set->cmd2 & CMD2_OBITS) 125 newmode |= value & set->bits; 126 } 127 break; 128 129 case '+': 130 newmode |= set->bits; 131 break; 132 133 case '-': 134 newmode &= ~set->bits; 135 break; 136 137 case 'X': 138 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 139 newmode |= set->bits; 140 break; 141 142 case '\0': 143 default: 144 #ifdef SETMODE_DEBUG 145 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 146 #endif 147 return (newmode); 148 } 149 } 150 151 #define ADDCMD(a, b, c, d) \ 152 if (set >= endset) { \ 153 BITCMD *newset; \ 154 setlen += SET_LEN_INCR; \ 155 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 156 if (newset == NULL) \ 157 goto out; \ 158 set = newset + (set - saveset); \ 159 saveset = newset; \ 160 endset = newset + (setlen - 2); \ 161 } \ 162 set = addcmd(set, (mode_t)(a), (mode_t)(b), (mode_t)(c), (d)) 163 164 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 165 166 void * 167 setmode(const char *p) 168 { 169 int serrno; 170 char op, *ep; 171 BITCMD *set, *saveset, *endset; 172 sigset_t sigset, sigoset; 173 mode_t mask, perm, permXbits, who; 174 long perml; 175 int equalopdone; 176 int setlen; 177 178 if (!*p) { 179 errno = EINVAL; 180 return (NULL); 181 } 182 183 /* 184 * Get a copy of the mask for the permissions that are mask relative. 185 * Flip the bits, we want what's not set. Since it's possible that 186 * the caller is opening files inside a signal handler, protect them 187 * as best we can. 188 */ 189 sigfillset(&sigset); 190 (void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset); 191 (void)umask(mask = umask(0)); 192 mask = ~mask; 193 (void)_sigprocmask(SIG_SETMASK, &sigoset, NULL); 194 195 setlen = SET_LEN + 2; 196 197 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 198 return (NULL); 199 saveset = set; 200 endset = set + (setlen - 2); 201 202 /* 203 * If an absolute number, get it and return; disallow non-octal digits 204 * or illegal bits. 205 */ 206 if (isdigit((unsigned char)*p)) { 207 errno = 0; 208 perml = strtol(p, &ep, 8); 209 if (*ep) { 210 errno = EINVAL; 211 goto out; 212 } 213 if (errno == ERANGE && (perml == LONG_MAX || perml == LONG_MIN)) 214 goto out; 215 if (perml & ~(STANDARD_BITS|S_ISTXT)) { 216 errno = EINVAL; 217 goto out; 218 } 219 perm = (mode_t)perml; 220 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 221 set->cmd = 0; 222 return (saveset); 223 } 224 225 /* 226 * Build list of structures to set/clear/copy bits as described by 227 * each clause of the symbolic mode. 228 */ 229 equalopdone = 0; 230 for (;;) { 231 /* First, find out which bits might be modified. */ 232 for (who = 0;; ++p) { 233 switch (*p) { 234 case 'a': 235 who |= STANDARD_BITS; 236 break; 237 case 'u': 238 who |= S_ISUID|S_IRWXU; 239 break; 240 case 'g': 241 who |= S_ISGID|S_IRWXG; 242 break; 243 case 'o': 244 who |= S_IRWXO; 245 break; 246 default: 247 goto getop; 248 } 249 } 250 251 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 252 errno = EINVAL; 253 goto out; 254 } 255 if (op == '=') 256 equalopdone = 0; 257 258 who &= ~S_ISTXT; 259 for (perm = 0, permXbits = 0;; ++p) { 260 switch (*p) { 261 case 'r': 262 perm |= S_IRUSR|S_IRGRP|S_IROTH; 263 break; 264 case 's': 265 /* If only "other" bits ignore set-id. */ 266 if (!who || who & ~S_IRWXO) 267 perm |= S_ISUID|S_ISGID; 268 break; 269 case 't': 270 /* If only "other" bits ignore sticky. */ 271 if (!who || who & ~S_IRWXO) { 272 who |= S_ISTXT; 273 perm |= S_ISTXT; 274 } 275 break; 276 case 'w': 277 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 278 break; 279 case 'X': 280 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 281 break; 282 case 'x': 283 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 284 break; 285 case 'u': 286 case 'g': 287 case 'o': 288 /* 289 * When ever we hit 'u', 'g', or 'o', we have 290 * to flush out any partial mode that we have, 291 * and then do the copying of the mode bits. 292 */ 293 if (perm) { 294 ADDCMD(op, who, perm, mask); 295 perm = 0; 296 } 297 if (op == '=') 298 equalopdone = 1; 299 if (op == '+' && permXbits) { 300 ADDCMD('X', who, permXbits, mask); 301 permXbits = 0; 302 } 303 ADDCMD(*p, who, op, mask); 304 break; 305 306 default: 307 /* 308 * Add any permissions that we haven't already 309 * done. 310 */ 311 if (perm || (op == '=' && !equalopdone)) { 312 if (op == '=') 313 equalopdone = 1; 314 ADDCMD(op, who, perm, mask); 315 perm = 0; 316 } 317 if (permXbits) { 318 ADDCMD('X', who, permXbits, mask); 319 permXbits = 0; 320 } 321 goto apply; 322 } 323 } 324 325 apply: if (!*p) 326 break; 327 if (*p != ',') 328 goto getop; 329 ++p; 330 } 331 set->cmd = 0; 332 #ifdef SETMODE_DEBUG 333 (void)printf("Before compress_mode()\n"); 334 dumpmode(saveset); 335 #endif 336 compress_mode(saveset); 337 #ifdef SETMODE_DEBUG 338 (void)printf("After compress_mode()\n"); 339 dumpmode(saveset); 340 #endif 341 return (saveset); 342 out: 343 serrno = errno; 344 free(saveset); 345 errno = serrno; 346 return NULL; 347 } 348 349 static BITCMD * 350 addcmd(BITCMD *set, mode_t op, mode_t who, mode_t oparg, mode_t mask) 351 { 352 switch (op) { 353 case '=': 354 set->cmd = '-'; 355 set->bits = who ? who : STANDARD_BITS; 356 set++; 357 358 op = '+'; 359 /* FALLTHROUGH */ 360 case '+': 361 case '-': 362 case 'X': 363 set->cmd = op; 364 set->bits = (who ? who : mask) & oparg; 365 break; 366 367 case 'u': 368 case 'g': 369 case 'o': 370 set->cmd = op; 371 if (who) { 372 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 373 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 374 ((who & S_IROTH) ? CMD2_OBITS : 0); 375 set->bits = (mode_t)~0; 376 } else { 377 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 378 set->bits = mask; 379 } 380 381 if (oparg == '+') 382 set->cmd2 |= CMD2_SET; 383 else if (oparg == '-') 384 set->cmd2 |= CMD2_CLR; 385 else if (oparg == '=') 386 set->cmd2 |= CMD2_SET|CMD2_CLR; 387 break; 388 } 389 return (set + 1); 390 } 391 392 #ifdef SETMODE_DEBUG 393 static void 394 dumpmode(BITCMD *set) 395 { 396 for (; set->cmd; ++set) 397 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 398 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 399 set->cmd2 & CMD2_CLR ? " CLR" : "", 400 set->cmd2 & CMD2_SET ? " SET" : "", 401 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 402 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 403 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 404 } 405 #endif 406 407 /* 408 * Given an array of bitcmd structures, compress by compacting consecutive 409 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 410 * 'g' and 'o' commands continue to be separate. They could probably be 411 * compacted, but it's not worth the effort. 412 */ 413 static void 414 compress_mode(BITCMD *set) 415 { 416 BITCMD *nset; 417 int setbits, clrbits, Xbits, op; 418 419 for (nset = set;;) { 420 /* Copy over any 'u', 'g' and 'o' commands. */ 421 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 422 *set++ = *nset++; 423 if (!op) 424 return; 425 } 426 427 for (setbits = clrbits = Xbits = 0;; nset++) { 428 if ((op = nset->cmd) == '-') { 429 clrbits |= nset->bits; 430 setbits &= ~nset->bits; 431 Xbits &= ~nset->bits; 432 } else if (op == '+') { 433 setbits |= nset->bits; 434 clrbits &= ~nset->bits; 435 Xbits &= ~nset->bits; 436 } else if (op == 'X') 437 Xbits |= nset->bits & ~setbits; 438 else 439 break; 440 } 441 if (clrbits) { 442 set->cmd = '-'; 443 set->cmd2 = 0; 444 set->bits = clrbits; 445 set++; 446 } 447 if (setbits) { 448 set->cmd = '+'; 449 set->cmd2 = 0; 450 set->bits = setbits; 451 set++; 452 } 453 if (Xbits) { 454 set->cmd = 'X'; 455 set->cmd2 = 0; 456 set->bits = Xbits; 457 set++; 458 } 459 } 460 } 461