1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1993 Paul Kranenburg 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 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Paul Kranenburg. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/param.h> 37 #include <sys/wait.h> 38 39 #include <machine/elf.h> 40 41 #include <arpa/inet.h> 42 43 #include <dlfcn.h> 44 #include <err.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <gelf.h> 48 #include <libelf.h> 49 #include <rtld_paths.h> 50 #include <stdbool.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 /* 57 * 32-bit ELF data structures can only be used if the system header[s] declare 58 * them. There is no official macro for determining whether they are declared, 59 * so check for the existence of one of the 32-macros defined in elf(5). 60 */ 61 #ifdef ELF32_R_TYPE 62 #define ELF32_SUPPORTED 63 #endif 64 65 #define LDD_SETENV(name, value, overwrite) do { \ 66 setenv("LD_" name, value, overwrite); \ 67 setenv("LD_32_" name, value, overwrite); \ 68 } while (0) 69 70 #define LDD_UNSETENV(name) do { \ 71 unsetenv("LD_" name); \ 72 unsetenv("LD_32_" name); \ 73 } while (0) 74 75 static int is_executable(const char *fname, int fd, int *is_shlib, 76 int *type); 77 static void usage(void); 78 79 #define TYPE_UNKNOWN 0 80 #define TYPE_ELF 1 /* Architecture default */ 81 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 82 #define TYPE_ELF32 2 /* Explicit 32 bits on architectures >32 bits */ 83 84 #define _PATH_LDD32 "/usr/bin/ldd32" 85 86 static int 87 execldd32(char *file, char *fmt1, char *fmt2, int aflag) 88 { 89 char *argv[9]; 90 int i, rval, status; 91 92 LDD_UNSETENV("TRACE_LOADED_OBJECTS"); 93 rval = 0; 94 i = 0; 95 argv[i++] = strdup(_PATH_LDD32); 96 if (aflag) 97 argv[i++] = strdup("-a"); 98 if (fmt1 != NULL) { 99 argv[i++] = strdup("-f"); 100 argv[i++] = strdup(fmt1); 101 } 102 if (fmt2 != NULL) { 103 argv[i++] = strdup("-f"); 104 argv[i++] = strdup(fmt2); 105 } 106 argv[i++] = strdup(file); 107 argv[i++] = NULL; 108 109 switch (fork()) { 110 case -1: 111 err(1, "fork"); 112 break; 113 case 0: 114 execv(_PATH_LDD32, argv); 115 warn("%s", _PATH_LDD32); 116 _exit(127); 117 break; 118 default: 119 if (wait(&status) < 0) 120 rval = 1; 121 else if (WIFSIGNALED(status)) 122 rval = 1; 123 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) 124 rval = 1; 125 break; 126 } 127 while (i--) 128 free(argv[i]); 129 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 130 return (rval); 131 } 132 #endif 133 134 int 135 main(int argc, char *argv[]) 136 { 137 char *fmt1, *fmt2; 138 const char *rtld; 139 int aflag, c, fd, rval, status, is_shlib, rv, type; 140 141 aflag = 0; 142 fmt1 = fmt2 = NULL; 143 144 while ((c = getopt(argc, argv, "af:")) != -1) { 145 switch (c) { 146 case 'a': 147 aflag++; 148 break; 149 case 'f': 150 if (fmt1 != NULL) { 151 if (fmt2 != NULL) 152 errx(1, "too many formats"); 153 fmt2 = optarg; 154 } else 155 fmt1 = optarg; 156 break; 157 default: 158 usage(); 159 /* NOTREACHED */ 160 } 161 } 162 argc -= optind; 163 argv += optind; 164 165 if (argc <= 0) { 166 usage(); 167 /* NOTREACHED */ 168 } 169 170 rval = 0; 171 for (; argc > 0; argc--, argv++) { 172 if ((fd = open(*argv, O_RDONLY | O_VERIFY, 0)) < 0) { 173 warn("%s", *argv); 174 rval |= 1; 175 continue; 176 } 177 rv = is_executable(*argv, fd, &is_shlib, &type); 178 close(fd); 179 if (rv == 0) { 180 rval |= 1; 181 continue; 182 } 183 184 switch (type) { 185 case TYPE_ELF: 186 break; 187 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 188 case TYPE_ELF32: 189 rval |= execldd32(*argv, fmt1, fmt2, aflag); 190 continue; 191 #endif 192 case TYPE_UNKNOWN: 193 default: 194 /* 195 * This shouldn't happen unless is_executable() 196 * is broken. 197 */ 198 errx(EDOOFUS, "unknown executable type"); 199 } 200 201 /* ld.so magic */ 202 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 203 if (fmt1 != NULL) 204 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT1", fmt1, 1); 205 if (fmt2 != NULL) 206 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT2", fmt2, 1); 207 208 LDD_SETENV("TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1); 209 if (aflag) 210 LDD_SETENV("TRACE_LOADED_OBJECTS_ALL", "1", 1); 211 else if (fmt1 == NULL && fmt2 == NULL) 212 /* Default formats */ 213 printf("%s:\n", *argv); 214 fflush(stdout); 215 216 switch (fork()) { 217 case -1: 218 err(1, "fork"); 219 break; 220 default: 221 if (wait(&status) < 0) { 222 warn("wait"); 223 rval |= 1; 224 } else if (WIFSIGNALED(status)) { 225 fprintf(stderr, "%s: signal %d\n", *argv, 226 WTERMSIG(status)); 227 rval |= 1; 228 } else if (WIFEXITED(status) && 229 WEXITSTATUS(status) != 0) { 230 fprintf(stderr, "%s: exit status %d\n", *argv, 231 WEXITSTATUS(status)); 232 rval |= 1; 233 } 234 break; 235 case 0: 236 rtld = _PATH_RTLD; 237 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 238 if (type == TYPE_ELF32) 239 rtld = _COMPAT32_PATH_RTLD; 240 #endif 241 if (is_shlib == 0) { 242 execl(rtld, rtld, "--", 243 *argv, (char *)NULL); 244 warn("%s", *argv); 245 } else if (fmt1 == NULL && fmt2 == NULL && !aflag) { 246 dlopen(*argv, RTLD_TRACE); 247 warnx("%s: %s", *argv, dlerror()); 248 } else { 249 execl(rtld, rtld, "-d", "--", 250 *argv, (char *)NULL); 251 } 252 _exit(1); 253 } 254 } 255 256 return (rval); 257 } 258 259 static void 260 usage(void) 261 { 262 263 fprintf(stderr, "usage: ldd [-a] [-f format] program ...\n"); 264 exit(1); 265 } 266 267 static bool 268 has_freebsd_abi_tag(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, 269 size_t len) 270 { 271 Elf_Data dst, src; 272 const Elf_Note *note; 273 char *buf; 274 const char *name; 275 void *copy; 276 size_t namesz, descsz; 277 bool has_abi_tag; 278 279 buf = elf_rawfile(elf, NULL); 280 if (buf == NULL) { 281 warnx("%s: %s", fname, elf_errmsg(0)); 282 return (false); 283 } 284 285 memset(&src, 0, sizeof(src)); 286 src.d_buf = buf + offset; 287 src.d_size = len; 288 src.d_type = ELF_T_NOTE; 289 src.d_version = EV_CURRENT; 290 291 memset(&dst, 0, sizeof(dst)); 292 dst.d_buf = copy = malloc(len); 293 dst.d_size = len; 294 dst.d_type = ELF_T_NOTE; 295 dst.d_version = EV_CURRENT; 296 297 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 298 warnx("%s: failed to parse notes: %s", fname, elf_errmsg(0)); 299 free(copy); 300 return (false); 301 } 302 303 buf = copy; 304 has_abi_tag = false; 305 for (;;) { 306 if (len < sizeof(*note)) 307 break; 308 309 note = (const void *)buf; 310 buf += sizeof(*note); 311 len -= sizeof(*note); 312 313 namesz = roundup2(note->n_namesz, sizeof(uint32_t)); 314 descsz = roundup2(note->n_descsz, sizeof(uint32_t)); 315 if (len < namesz + descsz) 316 break; 317 318 name = buf; 319 if (note->n_namesz == sizeof(ELF_NOTE_FREEBSD) && 320 strncmp(name, ELF_NOTE_FREEBSD, note->n_namesz) == 0 && 321 note->n_type == NT_FREEBSD_ABI_TAG && 322 note->n_descsz == sizeof(uint32_t)) { 323 has_abi_tag = true; 324 break; 325 } 326 327 buf += namesz + descsz; 328 len -= namesz + descsz; 329 } 330 331 free(copy); 332 return (has_abi_tag); 333 } 334 335 static bool 336 is_pie(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, size_t len) 337 { 338 Elf_Data dst, src; 339 char *buf; 340 void *copy; 341 const GElf_Dyn *dyn; 342 size_t dynsize; 343 u_int count, i; 344 bool pie; 345 346 buf = elf_rawfile(elf, NULL); 347 if (buf == NULL) { 348 warnx("%s: %s", fname, elf_errmsg(0)); 349 return (false); 350 } 351 352 dynsize = gelf_fsize(elf, ELF_T_DYN, 1, EV_CURRENT); 353 if (dynsize == 0) { 354 warnx("%s: %s", fname, elf_errmsg(0)); 355 return (false); 356 } 357 count = len / dynsize; 358 359 memset(&src, 0, sizeof(src)); 360 src.d_buf = buf + offset; 361 src.d_size = len; 362 src.d_type = ELF_T_DYN; 363 src.d_version = EV_CURRENT; 364 365 memset(&dst, 0, sizeof(dst)); 366 dst.d_buf = copy = malloc(count * sizeof(*dyn)); 367 dst.d_size = count * sizeof(*dyn); 368 dst.d_type = ELF_T_DYN; 369 dst.d_version = EV_CURRENT; 370 371 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 372 warnx("%s: failed to parse .dynamic: %s", fname, elf_errmsg(0)); 373 free(copy); 374 return (false); 375 } 376 377 dyn = copy; 378 pie = false; 379 for (i = 0; i < count; i++) { 380 if (dyn[i].d_tag != DT_FLAGS_1) 381 continue; 382 383 pie = (dyn[i].d_un.d_val & DF_1_PIE) != 0; 384 break; 385 } 386 387 free(copy); 388 return (pie); 389 } 390 391 static int 392 is_executable(const char *fname, int fd, int *is_shlib, int *type) 393 { 394 Elf *elf; 395 GElf_Ehdr ehdr; 396 GElf_Phdr phdr; 397 bool dynamic, freebsd, pie; 398 int i; 399 400 *is_shlib = 0; 401 *type = TYPE_UNKNOWN; 402 dynamic = false; 403 freebsd = false; 404 pie = false; 405 406 if (elf_version(EV_CURRENT) == EV_NONE) { 407 warnx("unsupported libelf"); 408 return (0); 409 } 410 elf = elf_begin(fd, ELF_C_READ, NULL); 411 if (elf == NULL) { 412 warnx("%s: %s", fname, elf_errmsg(0)); 413 return (0); 414 } 415 if (elf_kind(elf) != ELF_K_ELF) { 416 elf_end(elf); 417 warnx("%s: not a dynamic ELF executable", fname); 418 return (0); 419 } 420 if (gelf_getehdr(elf, &ehdr) == NULL) { 421 warnx("%s: %s", fname, elf_errmsg(0)); 422 elf_end(elf); 423 return (0); 424 } 425 426 *type = TYPE_ELF; 427 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 428 if (gelf_getclass(elf) == ELFCLASS32) { 429 *type = TYPE_ELF32; 430 } 431 #endif 432 433 freebsd = ehdr.e_ident[EI_OSABI] == ELFOSABI_FREEBSD; 434 for (i = 0; i < ehdr.e_phnum; i++) { 435 if (gelf_getphdr(elf, i, &phdr) == NULL) { 436 warnx("%s: %s", fname, elf_errmsg(0)); 437 elf_end(elf); 438 return (0); 439 } 440 switch (phdr.p_type) { 441 case PT_NOTE: 442 if (ehdr.e_ident[EI_OSABI] == ELFOSABI_NONE && !freebsd) 443 freebsd = has_freebsd_abi_tag(fname, elf, &ehdr, 444 phdr.p_offset, phdr.p_filesz); 445 break; 446 case PT_DYNAMIC: 447 dynamic = true; 448 if (ehdr.e_type == ET_DYN) 449 pie = is_pie(fname, elf, &ehdr, phdr.p_offset, 450 phdr.p_filesz); 451 break; 452 } 453 } 454 455 if (!dynamic) { 456 elf_end(elf); 457 warnx("%s: not a dynamic ELF executable", fname); 458 return (0); 459 } 460 461 if (ehdr.e_type == ET_DYN && !pie) { 462 *is_shlib = 1; 463 464 if (!freebsd) { 465 elf_end(elf); 466 warnx("%s: not a FreeBSD ELF shared object", fname); 467 return (0); 468 } 469 } 470 471 elf_end(elf); 472 return (1); 473 } 474