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