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
execldd32(char * file,char * fmt1,char * fmt2,int aflag)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
main(int argc,char * argv[])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
usage(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
has_freebsd_abi_tag(const char * fname,Elf * elf,GElf_Ehdr * ehdr,off_t offset,size_t len)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
is_pie(const char * fname,Elf * elf,GElf_Ehdr * ehdr,off_t offset,size_t len)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
is_executable(const char * fname,int fd,int * is_shlib,int * type)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