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 <stdbool.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 55 /* 56 * 32-bit ELF data structures can only be used if the system header[s] declare 57 * them. There is no official macro for determining whether they are declared, 58 * so check for the existence of one of the 32-macros defined in elf(5). 59 */ 60 #ifdef ELF32_R_TYPE 61 #define ELF32_SUPPORTED 62 #endif 63 64 #define LDD_SETENV(name, value, overwrite) do { \ 65 setenv("LD_" name, value, overwrite); \ 66 setenv("LD_32_" name, value, overwrite); \ 67 } while (0) 68 69 #define LDD_UNSETENV(name) do { \ 70 unsetenv("LD_" name); \ 71 unsetenv("LD_32_" name); \ 72 } while (0) 73 74 static int is_executable(const char *fname, int fd, int *is_shlib, 75 int *type); 76 static void usage(void); 77 78 #define TYPE_UNKNOWN 0 79 #define TYPE_ELF 1 /* Architecture default */ 80 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 81 #define TYPE_ELF32 2 /* Explicit 32 bits on architectures >32 bits */ 82 83 #define _PATH_LDD32 "/usr/bin/ldd32" 84 85 static int 86 execldd32(char *file, char *fmt1, char *fmt2, int aflag, int vflag) 87 { 88 char *argv[9]; 89 int i, rval, status; 90 91 LDD_UNSETENV("TRACE_LOADED_OBJECTS"); 92 rval = 0; 93 i = 0; 94 argv[i++] = strdup(_PATH_LDD32); 95 if (aflag) 96 argv[i++] = strdup("-a"); 97 if (vflag) 98 argv[i++] = strdup("-v"); 99 if (fmt1 != NULL) { 100 argv[i++] = strdup("-f"); 101 argv[i++] = strdup(fmt1); 102 } 103 if (fmt2 != NULL) { 104 argv[i++] = strdup("-f"); 105 argv[i++] = strdup(fmt2); 106 } 107 argv[i++] = strdup(file); 108 argv[i++] = NULL; 109 110 switch (fork()) { 111 case -1: 112 err(1, "fork"); 113 break; 114 case 0: 115 execv(_PATH_LDD32, argv); 116 warn("%s", _PATH_LDD32); 117 _exit(127); 118 break; 119 default: 120 if (wait(&status) < 0) 121 rval = 1; 122 else if (WIFSIGNALED(status)) 123 rval = 1; 124 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) 125 rval = 1; 126 break; 127 } 128 while (i--) 129 free(argv[i]); 130 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 131 return (rval); 132 } 133 #endif 134 135 int 136 main(int argc, char *argv[]) 137 { 138 char *fmt1, *fmt2; 139 int rval, c, aflag, vflag; 140 141 aflag = vflag = 0; 142 fmt1 = fmt2 = NULL; 143 144 while ((c = getopt(argc, argv, "af:v")) != -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 case 'v': 158 vflag++; 159 break; 160 default: 161 usage(); 162 /* NOTREACHED */ 163 } 164 } 165 argc -= optind; 166 argv += optind; 167 168 if (vflag && fmt1 != NULL) 169 errx(1, "-v may not be used with -f"); 170 171 if (argc <= 0) { 172 usage(); 173 /* NOTREACHED */ 174 } 175 176 rval = 0; 177 for (; argc > 0; argc--, argv++) { 178 int fd, status, is_shlib, rv, type; 179 180 if ((fd = open(*argv, O_RDONLY, 0)) < 0) { 181 warn("%s", *argv); 182 rval |= 1; 183 continue; 184 } 185 rv = is_executable(*argv, fd, &is_shlib, &type); 186 close(fd); 187 if (rv == 0) { 188 rval |= 1; 189 continue; 190 } 191 192 switch (type) { 193 case TYPE_ELF: 194 break; 195 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 196 case TYPE_ELF32: 197 rval |= execldd32(*argv, fmt1, fmt2, aflag, vflag); 198 continue; 199 #endif 200 case TYPE_UNKNOWN: 201 default: 202 /* 203 * This shouldn't happen unless is_executable() 204 * is broken. 205 */ 206 errx(EDOOFUS, "unknown executable type"); 207 } 208 209 /* ld.so magic */ 210 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 211 if (fmt1 != NULL) 212 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT1", fmt1, 1); 213 if (fmt2 != NULL) 214 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT2", fmt2, 1); 215 216 LDD_SETENV("TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1); 217 if (aflag) 218 LDD_SETENV("TRACE_LOADED_OBJECTS_ALL", "1", 1); 219 else if (fmt1 == NULL && fmt2 == NULL) 220 /* Default formats */ 221 printf("%s:\n", *argv); 222 fflush(stdout); 223 224 switch (fork()) { 225 case -1: 226 err(1, "fork"); 227 break; 228 default: 229 if (wait(&status) < 0) { 230 warn("wait"); 231 rval |= 1; 232 } else if (WIFSIGNALED(status)) { 233 fprintf(stderr, "%s: signal %d\n", *argv, 234 WTERMSIG(status)); 235 rval |= 1; 236 } else if (WIFEXITED(status) && 237 WEXITSTATUS(status) != 0) { 238 fprintf(stderr, "%s: exit status %d\n", *argv, 239 WEXITSTATUS(status)); 240 rval |= 1; 241 } 242 break; 243 case 0: 244 if (is_shlib == 0) { 245 execl(*argv, *argv, (char *)NULL); 246 warn("%s", *argv); 247 } else { 248 dlopen(*argv, RTLD_TRACE); 249 warnx("%s: %s", *argv, dlerror()); 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] [-v] [-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