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, 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 if (is_shlib == 0) { 237 execl(*argv, *argv, (char *)NULL); 238 warn("%s", *argv); 239 } else if (fmt1 == NULL && fmt2 == NULL) { 240 dlopen(*argv, RTLD_TRACE); 241 warnx("%s: %s", *argv, dlerror()); 242 } else { 243 rtld = _PATH_RTLD; 244 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 245 if (type == TYPE_ELF32) 246 rtld = _COMPAT32_PATH_RTLD; 247 #endif 248 execl(rtld, rtld, "-d", "--", 249 *argv, (char *)NULL); 250 } 251 _exit(1); 252 } 253 } 254 255 return (rval); 256 } 257 258 static void 259 usage(void) 260 { 261 262 fprintf(stderr, "usage: ldd [-a] [-f format] program ...\n"); 263 exit(1); 264 } 265 266 static bool 267 has_freebsd_abi_tag(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, 268 size_t len) 269 { 270 Elf_Data dst, src; 271 const Elf_Note *note; 272 char *buf; 273 const char *name; 274 void *copy; 275 size_t namesz, descsz; 276 bool has_abi_tag; 277 278 buf = elf_rawfile(elf, NULL); 279 if (buf == NULL) { 280 warnx("%s: %s", fname, elf_errmsg(0)); 281 return (false); 282 } 283 284 memset(&src, 0, sizeof(src)); 285 src.d_buf = buf + offset; 286 src.d_size = len; 287 src.d_type = ELF_T_NOTE; 288 src.d_version = EV_CURRENT; 289 290 memset(&dst, 0, sizeof(dst)); 291 dst.d_buf = copy = malloc(len); 292 dst.d_size = len; 293 dst.d_type = ELF_T_NOTE; 294 dst.d_version = EV_CURRENT; 295 296 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 297 warnx("%s: failed to parse notes: %s", fname, elf_errmsg(0)); 298 free(copy); 299 return (false); 300 } 301 302 buf = copy; 303 has_abi_tag = false; 304 for (;;) { 305 if (len < sizeof(*note)) 306 break; 307 308 note = (const void *)buf; 309 buf += sizeof(*note); 310 len -= sizeof(*note); 311 312 namesz = roundup2(note->n_namesz, sizeof(uint32_t)); 313 descsz = roundup2(note->n_descsz, sizeof(uint32_t)); 314 if (len < namesz + descsz) 315 break; 316 317 name = buf; 318 if (note->n_namesz == sizeof(ELF_NOTE_FREEBSD) && 319 strncmp(name, ELF_NOTE_FREEBSD, note->n_namesz) == 0 && 320 note->n_type == NT_FREEBSD_ABI_TAG && 321 note->n_descsz == sizeof(uint32_t)) { 322 has_abi_tag = true; 323 break; 324 } 325 326 buf += namesz + descsz; 327 len -= namesz + descsz; 328 } 329 330 free(copy); 331 return (has_abi_tag); 332 } 333 334 static bool 335 is_pie(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, size_t len) 336 { 337 Elf_Data dst, src; 338 char *buf; 339 void *copy; 340 const GElf_Dyn *dyn; 341 size_t dynsize; 342 u_int count, i; 343 bool pie; 344 345 buf = elf_rawfile(elf, NULL); 346 if (buf == NULL) { 347 warnx("%s: %s", fname, elf_errmsg(0)); 348 return (false); 349 } 350 351 dynsize = gelf_fsize(elf, ELF_T_DYN, 1, EV_CURRENT); 352 if (dynsize == 0) { 353 warnx("%s: %s", fname, elf_errmsg(0)); 354 return (false); 355 } 356 count = len / dynsize; 357 358 memset(&src, 0, sizeof(src)); 359 src.d_buf = buf + offset; 360 src.d_size = len; 361 src.d_type = ELF_T_DYN; 362 src.d_version = EV_CURRENT; 363 364 memset(&dst, 0, sizeof(dst)); 365 dst.d_buf = copy = malloc(count * sizeof(*dyn)); 366 dst.d_size = count * sizeof(*dyn); 367 dst.d_type = ELF_T_DYN; 368 dst.d_version = EV_CURRENT; 369 370 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 371 warnx("%s: failed to parse .dynamic: %s", fname, elf_errmsg(0)); 372 free(copy); 373 return (false); 374 } 375 376 dyn = copy; 377 pie = false; 378 for (i = 0; i < count; i++) { 379 if (dyn[i].d_tag != DT_FLAGS_1) 380 continue; 381 382 pie = (dyn[i].d_un.d_val & DF_1_PIE) != 0; 383 break; 384 } 385 386 free(copy); 387 return (pie); 388 } 389 390 static int 391 is_executable(const char *fname, int fd, int *is_shlib, int *type) 392 { 393 Elf *elf; 394 GElf_Ehdr ehdr; 395 GElf_Phdr phdr; 396 bool dynamic, freebsd, pie; 397 int i; 398 399 *is_shlib = 0; 400 *type = TYPE_UNKNOWN; 401 dynamic = false; 402 freebsd = false; 403 pie = false; 404 405 if (elf_version(EV_CURRENT) == EV_NONE) { 406 warnx("unsupported libelf"); 407 return (0); 408 } 409 elf = elf_begin(fd, ELF_C_READ, NULL); 410 if (elf == NULL) { 411 warnx("%s: %s", fname, elf_errmsg(0)); 412 return (0); 413 } 414 if (elf_kind(elf) != ELF_K_ELF) { 415 elf_end(elf); 416 warnx("%s: not a dynamic ELF executable", fname); 417 return (0); 418 } 419 if (gelf_getehdr(elf, &ehdr) == NULL) { 420 warnx("%s: %s", fname, elf_errmsg(0)); 421 elf_end(elf); 422 return (0); 423 } 424 425 *type = TYPE_ELF; 426 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 427 if (gelf_getclass(elf) == ELFCLASS32) { 428 *type = TYPE_ELF32; 429 } 430 #endif 431 432 freebsd = ehdr.e_ident[EI_OSABI] == ELFOSABI_FREEBSD; 433 for (i = 0; i < ehdr.e_phnum; i++) { 434 if (gelf_getphdr(elf, i, &phdr) == NULL) { 435 warnx("%s: %s", fname, elf_errmsg(0)); 436 elf_end(elf); 437 return (0); 438 } 439 switch (phdr.p_type) { 440 case PT_NOTE: 441 if (ehdr.e_ident[EI_OSABI] == ELFOSABI_NONE && !freebsd) 442 freebsd = has_freebsd_abi_tag(fname, elf, &ehdr, 443 phdr.p_offset, phdr.p_filesz); 444 break; 445 case PT_DYNAMIC: 446 dynamic = true; 447 if (ehdr.e_type == ET_DYN) 448 pie = is_pie(fname, elf, &ehdr, phdr.p_offset, 449 phdr.p_filesz); 450 break; 451 } 452 } 453 454 if (!dynamic) { 455 elf_end(elf); 456 warnx("%s: not a dynamic ELF executable", fname); 457 return (0); 458 } 459 460 if (ehdr.e_type == ET_DYN && !pie) { 461 *is_shlib = 1; 462 463 if (!freebsd) { 464 elf_end(elf); 465 warnx("%s: not a FreeBSD ELF shared object", fname); 466 return (0); 467 } 468 } 469 470 elf_end(elf); 471 return (1); 472 } 473