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 #include <sys/param.h>
35 #include <sys/wait.h>
36
37 #include <machine/elf.h>
38
39 #include <arpa/inet.h>
40
41 #include <dlfcn.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <gelf.h>
46 #include <libelf.h>
47 #include <rtld_paths.h>
48 #include <stdbool.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53
54 /*
55 * 32-bit ELF data structures can only be used if the system header[s] declare
56 * them. There is no official macro for determining whether they are declared,
57 * so check for the existence of one of the 32-macros defined in elf(5).
58 */
59 #ifdef ELF32_R_TYPE
60 #define ELF32_SUPPORTED
61 #endif
62
63 #define LDD_SETENV(name, value, overwrite) do { \
64 setenv("LD_" name, value, overwrite); \
65 setenv("LD_32_" name, value, overwrite); \
66 } while (0)
67
68 #define LDD_UNSETENV(name) do { \
69 unsetenv("LD_" name); \
70 unsetenv("LD_32_" name); \
71 } while (0)
72
73 static int is_executable(const char *fname, int fd, int *is_shlib,
74 int *type);
75 static void usage(void);
76
77 #define TYPE_UNKNOWN 0
78 #define TYPE_ELF 1 /* Architecture default */
79 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
80 #define TYPE_ELF32 2 /* Explicit 32 bits on architectures >32 bits */
81
82 #define _PATH_LDD32 "/usr/bin/ldd32"
83
84 static int
execldd32(char * file,char * fmt1,char * fmt2,int aflag)85 execldd32(char *file, char *fmt1, char *fmt2, int aflag)
86 {
87 char *argv[9];
88 int i, rval, status;
89
90 LDD_UNSETENV("TRACE_LOADED_OBJECTS");
91 rval = 0;
92 i = 0;
93 argv[i++] = strdup(_PATH_LDD32);
94 if (aflag)
95 argv[i++] = strdup("-a");
96 if (fmt1 != NULL) {
97 argv[i++] = strdup("-f");
98 argv[i++] = strdup(fmt1);
99 }
100 if (fmt2 != NULL) {
101 argv[i++] = strdup("-f");
102 argv[i++] = strdup(fmt2);
103 }
104 argv[i++] = strdup(file);
105 argv[i++] = NULL;
106
107 switch (fork()) {
108 case -1:
109 err(1, "fork");
110 break;
111 case 0:
112 execv(_PATH_LDD32, argv);
113 warn("%s", _PATH_LDD32);
114 _exit(127);
115 break;
116 default:
117 if (wait(&status) < 0)
118 rval = 1;
119 else if (WIFSIGNALED(status))
120 rval = 1;
121 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
122 rval = 1;
123 break;
124 }
125 while (i--)
126 free(argv[i]);
127 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1);
128 return (rval);
129 }
130 #endif
131
132 int
main(int argc,char * argv[])133 main(int argc, char *argv[])
134 {
135 char *fmt1, *fmt2;
136 const char *rtld;
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 | O_VERIFY, 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 rtld = _PATH_RTLD;
235 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
236 if (type == TYPE_ELF32)
237 rtld = __PATH_RTLD("32");
238 #endif
239 if (is_shlib == 0) {
240 execl(rtld, rtld, "--",
241 *argv, (char *)NULL);
242 warn("%s", *argv);
243 } else if (fmt1 == NULL && fmt2 == NULL && !aflag) {
244 dlopen(*argv, RTLD_TRACE);
245 warnx("%s: %s", *argv, dlerror());
246 } else {
247 execl(rtld, rtld, "-d", "--",
248 *argv, (char *)NULL);
249 }
250 _exit(1);
251 }
252 }
253
254 return (rval);
255 }
256
257 static void
usage(void)258 usage(void)
259 {
260
261 fprintf(stderr,
262 "usage: ldd [-a] [-f format [-f format]] program ...\n");
263 exit(1);
264 }
265
266 static bool
has_freebsd_abi_tag(const char * fname,Elf * elf,GElf_Ehdr * ehdr,off_t offset,size_t len)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
is_pie(const char * fname,Elf * elf,GElf_Ehdr * ehdr,off_t offset,size_t len)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
is_executable(const char * fname,int fd,int * is_shlib,int * type)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