1 /* $NetBSD: funcs.c,v 1.16 2019/05/22 17:26:05 christos Exp $ */ 2 3 /* 4 * Copyright (c) Christos Zoulas 2003. 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 immediately at the beginning of the file, without modification, 12 * 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 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 #include "file.h" 30 31 #ifndef lint 32 #if 0 33 FILE_RCSID("@(#)$File: funcs.c,v 1.104 2019/05/07 02:27:11 christos Exp $") 34 #else 35 __RCSID("$NetBSD: funcs.c,v 1.16 2019/05/22 17:26:05 christos Exp $"); 36 #endif 37 #endif /* lint */ 38 39 #include "magic.h" 40 #include <assert.h> 41 #include <stdarg.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <ctype.h> 45 #if defined(HAVE_WCHAR_H) 46 #include <wchar.h> 47 #endif 48 #if defined(HAVE_WCTYPE_H) 49 #include <wctype.h> 50 #endif 51 #include <limits.h> 52 53 #ifndef SIZE_MAX 54 #define SIZE_MAX ((size_t)~0) 55 #endif 56 57 /* 58 * Like printf, only we append to a buffer. 59 */ 60 protected int 61 file_vprintf(struct magic_set *ms, const char *fmt, va_list ap) 62 { 63 int len; 64 char *buf, *newstr; 65 66 if (ms->event_flags & EVENT_HAD_ERR) 67 return 0; 68 len = vasprintf(&buf, fmt, ap); 69 if (len < 0) 70 goto out; 71 72 if (ms->o.buf != NULL) { 73 len = asprintf(&newstr, "%s%s", ms->o.buf, buf); 74 free(buf); 75 if (len < 0) 76 goto out; 77 free(ms->o.buf); 78 buf = newstr; 79 } 80 ms->o.buf = buf; 81 return 0; 82 out: 83 fprintf(stderr, "vasprintf failed (%s)", strerror(errno)); 84 return -1; 85 } 86 87 protected int 88 file_printf(struct magic_set *ms, const char *fmt, ...) 89 { 90 int rv; 91 va_list ap; 92 93 va_start(ap, fmt); 94 rv = file_vprintf(ms, fmt, ap); 95 va_end(ap); 96 return rv; 97 } 98 99 /* 100 * error - print best error message possible 101 */ 102 /*VARARGS*/ 103 __attribute__((__format__(__printf__, 3, 0))) 104 private void 105 file_error_core(struct magic_set *ms, int error, const char *f, va_list va, 106 size_t lineno) 107 { 108 /* Only the first error is ok */ 109 if (ms->event_flags & EVENT_HAD_ERR) 110 return; 111 if (lineno != 0) { 112 free(ms->o.buf); 113 ms->o.buf = NULL; 114 (void)file_printf(ms, "line %" SIZE_T_FORMAT "u:", lineno); 115 } 116 if (ms->o.buf && *ms->o.buf) 117 (void)file_printf(ms, " "); 118 (void)file_vprintf(ms, f, va); 119 if (error > 0) 120 (void)file_printf(ms, " (%s)", strerror(error)); 121 ms->event_flags |= EVENT_HAD_ERR; 122 ms->error = error; 123 } 124 125 /*VARARGS*/ 126 protected void 127 file_error(struct magic_set *ms, int error, const char *f, ...) 128 { 129 va_list va; 130 va_start(va, f); 131 file_error_core(ms, error, f, va, 0); 132 va_end(va); 133 } 134 135 /* 136 * Print an error with magic line number. 137 */ 138 /*VARARGS*/ 139 protected void 140 file_magerror(struct magic_set *ms, const char *f, ...) 141 { 142 va_list va; 143 va_start(va, f); 144 file_error_core(ms, 0, f, va, ms->line); 145 va_end(va); 146 } 147 148 protected void 149 file_oomem(struct magic_set *ms, size_t len) 150 { 151 file_error(ms, errno, "cannot allocate %" SIZE_T_FORMAT "u bytes", 152 len); 153 } 154 155 protected void 156 file_badseek(struct magic_set *ms) 157 { 158 file_error(ms, errno, "error seeking"); 159 } 160 161 protected void 162 file_badread(struct magic_set *ms) 163 { 164 file_error(ms, errno, "error reading"); 165 } 166 167 #ifndef COMPILE_ONLY 168 169 protected int 170 file_separator(struct magic_set *ms) 171 { 172 return file_printf(ms, "\n- "); 173 } 174 175 static int 176 checkdone(struct magic_set *ms, int *rv) 177 { 178 if ((ms->flags & MAGIC_CONTINUE) == 0) 179 return 1; 180 if (file_separator(ms) == -1) 181 *rv = -1; 182 return 0; 183 } 184 185 protected int 186 file_default(struct magic_set *ms, size_t nb) 187 { 188 if (ms->flags & MAGIC_MIME) { 189 if ((ms->flags & MAGIC_MIME_TYPE) && 190 file_printf(ms, "application/%s", 191 nb ? "octet-stream" : "x-empty") == -1) 192 return -1; 193 return 1; 194 } 195 if (ms->flags & MAGIC_APPLE) { 196 if (file_printf(ms, "UNKNUNKN") == -1) 197 return -1; 198 return 1; 199 } 200 if (ms->flags & MAGIC_EXTENSION) { 201 if (file_printf(ms, "???") == -1) 202 return -1; 203 return 1; 204 } 205 return 0; 206 } 207 208 /* 209 * The magic detection functions return: 210 * 1: found 211 * 0: not found 212 * -1: error 213 */ 214 /*ARGSUSED*/ 215 protected int 216 file_buffer(struct magic_set *ms, int fd, struct stat *st, 217 const char *inname __attribute__ ((__unused__)), 218 const void *buf, size_t nb) 219 { 220 int m = 0, rv = 0, looks_text = 0; 221 const char *code = NULL; 222 const char *code_mime = "binary"; 223 const char *def = "data"; 224 const char *ftype = NULL; 225 char *rbuf = NULL; 226 struct buffer b; 227 228 buffer_init(&b, fd, st, buf, nb); 229 ms->mode = b.st.st_mode; 230 231 if (nb == 0) { 232 def = "empty"; 233 goto simple; 234 } else if (nb == 1) { 235 def = "very short file (no magic)"; 236 goto simple; 237 } 238 239 if ((ms->flags & MAGIC_NO_CHECK_ENCODING) == 0) { 240 looks_text = file_encoding(ms, &b, NULL, 0, 241 &code, &code_mime, &ftype); 242 } 243 244 #ifdef __EMX__ 245 if ((ms->flags & MAGIC_NO_CHECK_APPTYPE) == 0 && inname) { 246 m = file_os2_apptype(ms, inname, &b); 247 if ((ms->flags & MAGIC_DEBUG) != 0) 248 (void)fprintf(stderr, "[try os2_apptype %d]\n", m); 249 switch (m) { 250 case -1: 251 return -1; 252 case 0: 253 break; 254 default: 255 return 1; 256 } 257 } 258 #endif 259 #if HAVE_FORK 260 /* try compression stuff */ 261 if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) == 0) { 262 m = file_zmagic(ms, &b, inname); 263 if ((ms->flags & MAGIC_DEBUG) != 0) 264 (void)fprintf(stderr, "[try zmagic %d]\n", m); 265 if (m) { 266 goto done_encoding; 267 } 268 } 269 #endif 270 /* Check if we have a tar file */ 271 if ((ms->flags & MAGIC_NO_CHECK_TAR) == 0) { 272 m = file_is_tar(ms, &b); 273 if ((ms->flags & MAGIC_DEBUG) != 0) 274 (void)fprintf(stderr, "[try tar %d]\n", m); 275 if (m) { 276 if (checkdone(ms, &rv)) 277 goto done; 278 } 279 } 280 281 /* Check if we have a JSON file */ 282 if ((ms->flags & MAGIC_NO_CHECK_JSON) == 0) { 283 m = file_is_json(ms, &b); 284 if ((ms->flags & MAGIC_DEBUG) != 0) 285 (void)fprintf(stderr, "[try json %d]\n", m); 286 if (m) { 287 if (checkdone(ms, &rv)) 288 goto done; 289 } 290 } 291 292 /* Check if we have a CDF file */ 293 if ((ms->flags & MAGIC_NO_CHECK_CDF) == 0) { 294 m = file_trycdf(ms, &b); 295 if ((ms->flags & MAGIC_DEBUG) != 0) 296 (void)fprintf(stderr, "[try cdf %d]\n", m); 297 if (m) { 298 if (checkdone(ms, &rv)) 299 goto done; 300 } 301 } 302 #ifdef BUILTIN_ELF 303 if ((ms->flags & MAGIC_NO_CHECK_ELF) == 0 && nb > 5 && fd != -1) { 304 file_pushbuf_t *pb; 305 /* 306 * We matched something in the file, so this 307 * *might* be an ELF file, and the file is at 308 * least 5 bytes long, so if it's an ELF file 309 * it has at least one byte past the ELF magic 310 * number - try extracting information from the 311 * ELF headers that cannot easily be extracted 312 * with rules in the magic file. We we don't 313 * print the information yet. 314 */ 315 if ((pb = file_push_buffer(ms)) == NULL) 316 return -1; 317 318 rv = file_tryelf(ms, &b); 319 rbuf = file_pop_buffer(ms, pb); 320 if (rv == -1) { 321 free(rbuf); 322 rbuf = NULL; 323 } 324 if ((ms->flags & MAGIC_DEBUG) != 0) 325 (void)fprintf(stderr, "[try elf %d]\n", m); 326 } 327 #endif 328 329 /* try soft magic tests */ 330 if ((ms->flags & MAGIC_NO_CHECK_SOFT) == 0) { 331 m = file_softmagic(ms, &b, NULL, NULL, BINTEST, looks_text); 332 if ((ms->flags & MAGIC_DEBUG) != 0) 333 (void)fprintf(stderr, "[try softmagic %d]\n", m); 334 if (m == 1 && rbuf) { 335 if (file_printf(ms, "%s", rbuf) == -1) 336 goto done; 337 } 338 if (m) { 339 if (checkdone(ms, &rv)) 340 goto done; 341 } 342 } 343 344 /* try text properties */ 345 if ((ms->flags & MAGIC_NO_CHECK_TEXT) == 0) { 346 347 m = file_ascmagic(ms, &b, looks_text); 348 if ((ms->flags & MAGIC_DEBUG) != 0) 349 (void)fprintf(stderr, "[try ascmagic %d]\n", m); 350 if (m) { 351 goto done; 352 } 353 } 354 355 simple: 356 /* give up */ 357 if (m == 0) { 358 m = 1; 359 rv = file_default(ms, nb); 360 if (rv == 0) 361 if (file_printf(ms, "%s", def) == -1) 362 rv = -1; 363 } 364 done: 365 if ((ms->flags & MAGIC_MIME_ENCODING) != 0) { 366 if (ms->flags & MAGIC_MIME_TYPE) 367 if (file_printf(ms, "; charset=") == -1) 368 rv = -1; 369 if (file_printf(ms, "%s", code_mime) == -1) 370 rv = -1; 371 } 372 #if HAVE_FORK 373 done_encoding: 374 #endif 375 free(rbuf); 376 buffer_fini(&b); 377 if (rv) 378 return rv; 379 380 return m; 381 } 382 #endif 383 384 protected int 385 file_reset(struct magic_set *ms, int checkloaded) 386 { 387 if (checkloaded && ms->mlist[0] == NULL) { 388 file_error(ms, 0, "no magic files loaded"); 389 return -1; 390 } 391 if (ms->o.buf) { 392 free(ms->o.buf); 393 ms->o.buf = NULL; 394 } 395 if (ms->o.pbuf) { 396 free(ms->o.pbuf); 397 ms->o.pbuf = NULL; 398 } 399 ms->event_flags &= ~EVENT_HAD_ERR; 400 ms->error = -1; 401 return 0; 402 } 403 404 #define OCTALIFY(n, o) \ 405 /*LINTED*/ \ 406 (void)(*(n)++ = '\\', \ 407 *(n)++ = ((CAST(uint32_t, *(o)) >> 6) & 3) + '0', \ 408 *(n)++ = ((CAST(uint32_t, *(o)) >> 3) & 7) + '0', \ 409 *(n)++ = ((CAST(uint32_t, *(o)) >> 0) & 7) + '0', \ 410 (o)++) 411 412 protected const char * 413 file_getbuffer(struct magic_set *ms) 414 { 415 char *pbuf, *op, *np; 416 size_t psize, len; 417 418 if (ms->event_flags & EVENT_HAD_ERR) 419 return NULL; 420 421 if (ms->flags & MAGIC_RAW) 422 return ms->o.buf; 423 424 if (ms->o.buf == NULL) 425 return NULL; 426 427 /* * 4 is for octal representation, + 1 is for NUL */ 428 len = strlen(ms->o.buf); 429 if (len > (SIZE_MAX - 1) / 4) { 430 file_oomem(ms, len); 431 return NULL; 432 } 433 psize = len * 4 + 1; 434 if ((pbuf = CAST(char *, realloc(ms->o.pbuf, psize))) == NULL) { 435 file_oomem(ms, psize); 436 return NULL; 437 } 438 ms->o.pbuf = pbuf; 439 440 #if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH) 441 { 442 mbstate_t state; 443 wchar_t nextchar; 444 int mb_conv = 1; 445 size_t bytesconsumed; 446 char *eop; 447 (void)memset(&state, 0, sizeof(mbstate_t)); 448 449 np = ms->o.pbuf; 450 op = ms->o.buf; 451 eop = op + len; 452 453 while (op < eop) { 454 bytesconsumed = mbrtowc(&nextchar, op, 455 CAST(size_t, eop - op), &state); 456 if (bytesconsumed == CAST(size_t, -1) || 457 bytesconsumed == CAST(size_t, -2)) { 458 mb_conv = 0; 459 break; 460 } 461 462 if (iswprint(nextchar)) { 463 (void)memcpy(np, op, bytesconsumed); 464 op += bytesconsumed; 465 np += bytesconsumed; 466 } else { 467 while (bytesconsumed-- > 0) 468 OCTALIFY(np, op); 469 } 470 } 471 *np = '\0'; 472 473 /* Parsing succeeded as a multi-byte sequence */ 474 if (mb_conv != 0) 475 return ms->o.pbuf; 476 } 477 #endif 478 479 for (np = ms->o.pbuf, op = ms->o.buf; *op;) { 480 if (isprint(CAST(unsigned char, *op))) { 481 *np++ = *op++; 482 } else { 483 OCTALIFY(np, op); 484 } 485 } 486 *np = '\0'; 487 return ms->o.pbuf; 488 } 489 490 protected int 491 file_check_mem(struct magic_set *ms, unsigned int level) 492 { 493 size_t len; 494 495 if (level >= ms->c.len) { 496 len = (ms->c.len = 20 + level) * sizeof(*ms->c.li); 497 ms->c.li = CAST(struct level_info *, (ms->c.li == NULL) ? 498 malloc(len) : 499 realloc(ms->c.li, len)); 500 if (ms->c.li == NULL) { 501 file_oomem(ms, len); 502 return -1; 503 } 504 } 505 ms->c.li[level].got_match = 0; 506 #ifdef ENABLE_CONDITIONALS 507 ms->c.li[level].last_match = 0; 508 ms->c.li[level].last_cond = COND_NONE; 509 #endif /* ENABLE_CONDITIONALS */ 510 return 0; 511 } 512 513 protected size_t 514 file_printedlen(const struct magic_set *ms) 515 { 516 return ms->o.buf == NULL ? 0 : strlen(ms->o.buf); 517 } 518 519 protected int 520 file_replace(struct magic_set *ms, const char *pat, const char *rep) 521 { 522 file_regex_t rx; 523 int rc, rv = -1; 524 525 rc = file_regcomp(&rx, pat, REG_EXTENDED); 526 if (rc) { 527 file_regerror(&rx, rc, ms); 528 } else { 529 regmatch_t rm; 530 int nm = 0; 531 while (file_regexec(&rx, ms->o.buf, 1, &rm, 0) == 0) { 532 ms->o.buf[rm.rm_so] = '\0'; 533 if (file_printf(ms, "%s%s", rep, 534 rm.rm_eo != 0 ? ms->o.buf + rm.rm_eo : "") == -1) 535 goto out; 536 nm++; 537 } 538 rv = nm; 539 } 540 out: 541 file_regfree(&rx); 542 return rv; 543 } 544 545 protected int 546 file_regcomp(file_regex_t *rx, const char *pat, int flags) 547 { 548 #ifdef USE_C_LOCALE 549 rx->c_lc_ctype = newlocale(LC_CTYPE_MASK, "C", 0); 550 assert(rx->c_lc_ctype != NULL); 551 rx->old_lc_ctype = uselocale(rx->c_lc_ctype); 552 assert(rx->old_lc_ctype != NULL); 553 #else 554 rx->old_lc_ctype = setlocale(LC_CTYPE, "C"); 555 #endif 556 rx->pat = pat; 557 558 return rx->rc = regcomp(&rx->rx, pat, flags); 559 } 560 561 protected int 562 file_regexec(file_regex_t *rx, const char *str, size_t nmatch, 563 regmatch_t* pmatch, int eflags) 564 { 565 assert(rx->rc == 0); 566 /* XXX: force initialization because glibc does not always do this */ 567 memset(pmatch, 0, nmatch * sizeof(*pmatch)); 568 return regexec(&rx->rx, str, nmatch, pmatch, eflags); 569 } 570 571 protected void 572 file_regfree(file_regex_t *rx) 573 { 574 if (rx->rc == 0) 575 regfree(&rx->rx); 576 #ifdef USE_C_LOCALE 577 (void)uselocale(rx->old_lc_ctype); 578 freelocale(rx->c_lc_ctype); 579 #else 580 (void)setlocale(LC_CTYPE, rx->old_lc_ctype); 581 #endif 582 } 583 584 protected void 585 file_regerror(file_regex_t *rx, int rc, struct magic_set *ms) 586 { 587 char errmsg[512]; 588 589 (void)regerror(rc, &rx->rx, errmsg, sizeof(errmsg)); 590 file_magerror(ms, "regex error %d for `%s', (%s)", rc, rx->pat, 591 errmsg); 592 } 593 594 protected file_pushbuf_t * 595 file_push_buffer(struct magic_set *ms) 596 { 597 file_pushbuf_t *pb; 598 599 if (ms->event_flags & EVENT_HAD_ERR) 600 return NULL; 601 602 if ((pb = (CAST(file_pushbuf_t *, malloc(sizeof(*pb))))) == NULL) 603 return NULL; 604 605 pb->buf = ms->o.buf; 606 pb->offset = ms->offset; 607 608 ms->o.buf = NULL; 609 ms->offset = 0; 610 611 return pb; 612 } 613 614 protected char * 615 file_pop_buffer(struct magic_set *ms, file_pushbuf_t *pb) 616 { 617 char *rbuf; 618 619 if (ms->event_flags & EVENT_HAD_ERR) { 620 free(pb->buf); 621 free(pb); 622 return NULL; 623 } 624 625 rbuf = ms->o.buf; 626 627 ms->o.buf = pb->buf; 628 ms->offset = pb->offset; 629 630 free(pb); 631 return rbuf; 632 } 633 634 /* 635 * convert string to ascii printable format. 636 */ 637 protected char * 638 file_printable(char *buf, size_t bufsiz, const char *str, size_t slen) 639 { 640 char *ptr, *eptr = buf + bufsiz - 1; 641 const unsigned char *s = RCAST(const unsigned char *, str); 642 const unsigned char *es = s + slen; 643 644 for (ptr = buf; ptr < eptr && s < es && *s; s++) { 645 if (isprint(*s)) { 646 *ptr++ = *s; 647 continue; 648 } 649 if (ptr >= eptr - 3) 650 break; 651 *ptr++ = '\\'; 652 *ptr++ = ((CAST(unsigned int, *s) >> 6) & 7) + '0'; 653 *ptr++ = ((CAST(unsigned int, *s) >> 3) & 7) + '0'; 654 *ptr++ = ((CAST(unsigned int, *s) >> 0) & 7) + '0'; 655 } 656 *ptr = '\0'; 657 return buf; 658 } 659