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