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) 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 (fmt1 != NULL) { 98 argv[i++] = strdup("-f"); 99 argv[i++] = strdup(fmt1); 100 } 101 if (fmt2 != NULL) { 102 argv[i++] = strdup("-f"); 103 argv[i++] = strdup(fmt2); 104 } 105 argv[i++] = strdup(file); 106 argv[i++] = NULL; 107 108 switch (fork()) { 109 case -1: 110 err(1, "fork"); 111 break; 112 case 0: 113 execv(_PATH_LDD32, argv); 114 warn("%s", _PATH_LDD32); 115 _exit(127); 116 break; 117 default: 118 if (wait(&status) < 0) 119 rval = 1; 120 else if (WIFSIGNALED(status)) 121 rval = 1; 122 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) 123 rval = 1; 124 break; 125 } 126 while (i--) 127 free(argv[i]); 128 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 129 return (rval); 130 } 131 #endif 132 133 int 134 main(int argc, char *argv[]) 135 { 136 char *fmt1, *fmt2; 137 int aflag, c, fd, rval, status, is_shlib, rv, type; 138 139 aflag = 0; 140 fmt1 = fmt2 = NULL; 141 142 while ((c = getopt(argc, argv, "af:")) != -1) { 143 switch (c) { 144 case 'a': 145 aflag++; 146 break; 147 case 'f': 148 if (fmt1 != NULL) { 149 if (fmt2 != NULL) 150 errx(1, "too many formats"); 151 fmt2 = optarg; 152 } else 153 fmt1 = optarg; 154 break; 155 default: 156 usage(); 157 /* NOTREACHED */ 158 } 159 } 160 argc -= optind; 161 argv += optind; 162 163 if (argc <= 0) { 164 usage(); 165 /* NOTREACHED */ 166 } 167 168 rval = 0; 169 for (; argc > 0; argc--, argv++) { 170 if ((fd = open(*argv, O_RDONLY, 0)) < 0) { 171 warn("%s", *argv); 172 rval |= 1; 173 continue; 174 } 175 rv = is_executable(*argv, fd, &is_shlib, &type); 176 close(fd); 177 if (rv == 0) { 178 rval |= 1; 179 continue; 180 } 181 182 switch (type) { 183 case TYPE_ELF: 184 break; 185 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 186 case TYPE_ELF32: 187 rval |= execldd32(*argv, fmt1, fmt2, aflag); 188 continue; 189 #endif 190 case TYPE_UNKNOWN: 191 default: 192 /* 193 * This shouldn't happen unless is_executable() 194 * is broken. 195 */ 196 errx(EDOOFUS, "unknown executable type"); 197 } 198 199 /* ld.so magic */ 200 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1); 201 if (fmt1 != NULL) 202 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT1", fmt1, 1); 203 if (fmt2 != NULL) 204 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT2", fmt2, 1); 205 206 LDD_SETENV("TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1); 207 if (aflag) 208 LDD_SETENV("TRACE_LOADED_OBJECTS_ALL", "1", 1); 209 else if (fmt1 == NULL && fmt2 == NULL) 210 /* Default formats */ 211 printf("%s:\n", *argv); 212 fflush(stdout); 213 214 switch (fork()) { 215 case -1: 216 err(1, "fork"); 217 break; 218 default: 219 if (wait(&status) < 0) { 220 warn("wait"); 221 rval |= 1; 222 } else if (WIFSIGNALED(status)) { 223 fprintf(stderr, "%s: signal %d\n", *argv, 224 WTERMSIG(status)); 225 rval |= 1; 226 } else if (WIFEXITED(status) && 227 WEXITSTATUS(status) != 0) { 228 fprintf(stderr, "%s: exit status %d\n", *argv, 229 WEXITSTATUS(status)); 230 rval |= 1; 231 } 232 break; 233 case 0: 234 if (is_shlib == 0) { 235 execl(*argv, *argv, (char *)NULL); 236 warn("%s", *argv); 237 } else { 238 dlopen(*argv, RTLD_TRACE); 239 warnx("%s: %s", *argv, dlerror()); 240 } 241 _exit(1); 242 } 243 } 244 245 return (rval); 246 } 247 248 static void 249 usage(void) 250 { 251 252 fprintf(stderr, "usage: ldd [-a] [-f format] program ...\n"); 253 exit(1); 254 } 255 256 static bool 257 has_freebsd_abi_tag(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, 258 size_t len) 259 { 260 Elf_Data dst, src; 261 const Elf_Note *note; 262 char *buf; 263 const char *name; 264 void *copy; 265 size_t namesz, descsz; 266 bool has_abi_tag; 267 268 buf = elf_rawfile(elf, NULL); 269 if (buf == NULL) { 270 warnx("%s: %s", fname, elf_errmsg(0)); 271 return (false); 272 } 273 274 memset(&src, 0, sizeof(src)); 275 src.d_buf = buf + offset; 276 src.d_size = len; 277 src.d_type = ELF_T_NOTE; 278 src.d_version = EV_CURRENT; 279 280 memset(&dst, 0, sizeof(dst)); 281 dst.d_buf = copy = malloc(len); 282 dst.d_size = len; 283 dst.d_type = ELF_T_NOTE; 284 dst.d_version = EV_CURRENT; 285 286 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 287 warnx("%s: failed to parse notes: %s", fname, elf_errmsg(0)); 288 free(copy); 289 return (false); 290 } 291 292 buf = copy; 293 has_abi_tag = false; 294 for (;;) { 295 if (len < sizeof(*note)) 296 break; 297 298 note = (const void *)buf; 299 buf += sizeof(*note); 300 len -= sizeof(*note); 301 302 namesz = roundup2(note->n_namesz, sizeof(uint32_t)); 303 descsz = roundup2(note->n_descsz, sizeof(uint32_t)); 304 if (len < namesz + descsz) 305 break; 306 307 name = buf; 308 if (note->n_namesz == sizeof(ELF_NOTE_FREEBSD) && 309 strncmp(name, ELF_NOTE_FREEBSD, note->n_namesz) == 0 && 310 note->n_type == NT_FREEBSD_ABI_TAG && 311 note->n_descsz == sizeof(uint32_t)) { 312 has_abi_tag = true; 313 break; 314 } 315 316 buf += namesz + descsz; 317 len -= namesz + descsz; 318 } 319 320 free(copy); 321 return (has_abi_tag); 322 } 323 324 static bool 325 is_pie(const char *fname, Elf *elf, GElf_Ehdr *ehdr, off_t offset, size_t len) 326 { 327 Elf_Data dst, src; 328 char *buf; 329 void *copy; 330 const GElf_Dyn *dyn; 331 size_t dynsize; 332 u_int count, i; 333 bool pie; 334 335 buf = elf_rawfile(elf, NULL); 336 if (buf == NULL) { 337 warnx("%s: %s", fname, elf_errmsg(0)); 338 return (false); 339 } 340 341 dynsize = gelf_fsize(elf, ELF_T_DYN, 1, EV_CURRENT); 342 if (dynsize == 0) { 343 warnx("%s: %s", fname, elf_errmsg(0)); 344 return (false); 345 } 346 count = len / dynsize; 347 348 memset(&src, 0, sizeof(src)); 349 src.d_buf = buf + offset; 350 src.d_size = len; 351 src.d_type = ELF_T_DYN; 352 src.d_version = EV_CURRENT; 353 354 memset(&dst, 0, sizeof(dst)); 355 dst.d_buf = copy = malloc(count * sizeof(*dyn)); 356 dst.d_size = count * sizeof(*dyn); 357 dst.d_type = ELF_T_DYN; 358 dst.d_version = EV_CURRENT; 359 360 if (gelf_xlatetom(elf, &dst, &src, ehdr->e_ident[EI_DATA]) == NULL) { 361 warnx("%s: failed to parse .dynamic: %s", fname, elf_errmsg(0)); 362 free(copy); 363 return (false); 364 } 365 366 dyn = copy; 367 pie = false; 368 for (i = 0; i < count; i++) { 369 if (dyn[i].d_tag != DT_FLAGS_1) 370 continue; 371 372 pie = (dyn[i].d_un.d_val & DF_1_PIE) != 0; 373 break; 374 } 375 376 free(copy); 377 return (pie); 378 } 379 380 static int 381 is_executable(const char *fname, int fd, int *is_shlib, int *type) 382 { 383 Elf *elf; 384 GElf_Ehdr ehdr; 385 GElf_Phdr phdr; 386 bool dynamic, freebsd, pie; 387 int i; 388 389 *is_shlib = 0; 390 *type = TYPE_UNKNOWN; 391 dynamic = false; 392 freebsd = false; 393 pie = false; 394 395 if (elf_version(EV_CURRENT) == EV_NONE) { 396 warnx("unsupported libelf"); 397 return (0); 398 } 399 elf = elf_begin(fd, ELF_C_READ, NULL); 400 if (elf == NULL) { 401 warnx("%s: %s", fname, elf_errmsg(0)); 402 return (0); 403 } 404 if (elf_kind(elf) != ELF_K_ELF) { 405 elf_end(elf); 406 warnx("%s: not a dynamic ELF executable", fname); 407 return (0); 408 } 409 if (gelf_getehdr(elf, &ehdr) == NULL) { 410 warnx("%s: %s", fname, elf_errmsg(0)); 411 elf_end(elf); 412 return (0); 413 } 414 415 *type = TYPE_ELF; 416 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) 417 if (gelf_getclass(elf) == ELFCLASS32) { 418 *type = TYPE_ELF32; 419 } 420 #endif 421 422 freebsd = ehdr.e_ident[EI_OSABI] == ELFOSABI_FREEBSD; 423 for (i = 0; i < ehdr.e_phnum; i++) { 424 if (gelf_getphdr(elf, i, &phdr) == NULL) { 425 warnx("%s: %s", fname, elf_errmsg(0)); 426 elf_end(elf); 427 return (0); 428 } 429 switch (phdr.p_type) { 430 case PT_NOTE: 431 if (ehdr.e_ident[EI_OSABI] == ELFOSABI_NONE && !freebsd) 432 freebsd = has_freebsd_abi_tag(fname, elf, &ehdr, 433 phdr.p_offset, phdr.p_filesz); 434 break; 435 case PT_DYNAMIC: 436 dynamic = true; 437 if (ehdr.e_type == ET_DYN) 438 pie = is_pie(fname, elf, &ehdr, phdr.p_offset, 439 phdr.p_filesz); 440 break; 441 } 442 } 443 444 if (!dynamic) { 445 elf_end(elf); 446 warnx("%s: not a dynamic ELF executable", fname); 447 return (0); 448 } 449 450 if (ehdr.e_type == ET_DYN && !pie) { 451 *is_shlib = 1; 452 453 if (!freebsd) { 454 elf_end(elf); 455 warnx("%s: not a FreeBSD ELF shared object", fname); 456 return (0); 457 } 458 } 459 460 elf_end(elf); 461 return (1); 462 } 463