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 <rtld_paths.h>
50 #include <stdbool.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55
56 /*
57 * 32-bit ELF data structures can only be used if the system header[s] declare
58 * them. There is no official macro for determining whether they are declared,
59 * so check for the existence of one of the 32-macros defined in elf(5).
60 */
61 #ifdef ELF32_R_TYPE
62 #define ELF32_SUPPORTED
63 #endif
64
65 #define LDD_SETENV(name, value, overwrite) do { \
66 setenv("LD_" name, value, overwrite); \
67 setenv("LD_32_" name, value, overwrite); \
68 } while (0)
69
70 #define LDD_UNSETENV(name) do { \
71 unsetenv("LD_" name); \
72 unsetenv("LD_32_" name); \
73 } while (0)
74
75 static int is_executable(const char *fname, int fd, int *is_shlib,
76 int *type);
77 static void usage(void);
78
79 #define TYPE_UNKNOWN 0
80 #define TYPE_ELF 1 /* Architecture default */
81 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
82 #define TYPE_ELF32 2 /* Explicit 32 bits on architectures >32 bits */
83
84 #define _PATH_LDD32 "/usr/bin/ldd32"
85
86 static int
execldd32(char * file,char * fmt1,char * fmt2,int aflag)87 execldd32(char *file, char *fmt1, char *fmt2, int aflag)
88 {
89 char *argv[9];
90 int i, rval, status;
91
92 LDD_UNSETENV("TRACE_LOADED_OBJECTS");
93 rval = 0;
94 i = 0;
95 argv[i++] = strdup(_PATH_LDD32);
96 if (aflag)
97 argv[i++] = strdup("-a");
98 if (fmt1 != NULL) {
99 argv[i++] = strdup("-f");
100 argv[i++] = strdup(fmt1);
101 }
102 if (fmt2 != NULL) {
103 argv[i++] = strdup("-f");
104 argv[i++] = strdup(fmt2);
105 }
106 argv[i++] = strdup(file);
107 argv[i++] = NULL;
108
109 switch (fork()) {
110 case -1:
111 err(1, "fork");
112 break;
113 case 0:
114 execv(_PATH_LDD32, argv);
115 warn("%s", _PATH_LDD32);
116 _exit(127);
117 break;
118 default:
119 if (wait(&status) < 0)
120 rval = 1;
121 else if (WIFSIGNALED(status))
122 rval = 1;
123 else if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
124 rval = 1;
125 break;
126 }
127 while (i--)
128 free(argv[i]);
129 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1);
130 return (rval);
131 }
132 #endif
133
134 int
main(int argc,char * argv[])135 main(int argc, char *argv[])
136 {
137 char *fmt1, *fmt2;
138 const char *rtld;
139 int aflag, c, fd, rval, status, is_shlib, rv, type;
140
141 aflag = 0;
142 fmt1 = fmt2 = NULL;
143
144 while ((c = getopt(argc, argv, "af:")) != -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 default:
158 usage();
159 /* NOTREACHED */
160 }
161 }
162 argc -= optind;
163 argv += optind;
164
165 if (argc <= 0) {
166 usage();
167 /* NOTREACHED */
168 }
169
170 rval = 0;
171 for (; argc > 0; argc--, argv++) {
172 if ((fd = open(*argv, O_RDONLY, 0)) < 0) {
173 warn("%s", *argv);
174 rval |= 1;
175 continue;
176 }
177 rv = is_executable(*argv, fd, &is_shlib, &type);
178 close(fd);
179 if (rv == 0) {
180 rval |= 1;
181 continue;
182 }
183
184 switch (type) {
185 case TYPE_ELF:
186 break;
187 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
188 case TYPE_ELF32:
189 rval |= execldd32(*argv, fmt1, fmt2, aflag);
190 continue;
191 #endif
192 case TYPE_UNKNOWN:
193 default:
194 /*
195 * This shouldn't happen unless is_executable()
196 * is broken.
197 */
198 errx(EDOOFUS, "unknown executable type");
199 }
200
201 /* ld.so magic */
202 LDD_SETENV("TRACE_LOADED_OBJECTS", "yes", 1);
203 if (fmt1 != NULL)
204 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT1", fmt1, 1);
205 if (fmt2 != NULL)
206 LDD_SETENV("TRACE_LOADED_OBJECTS_FMT2", fmt2, 1);
207
208 LDD_SETENV("TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1);
209 if (aflag)
210 LDD_SETENV("TRACE_LOADED_OBJECTS_ALL", "1", 1);
211 else if (fmt1 == NULL && fmt2 == NULL)
212 /* Default formats */
213 printf("%s:\n", *argv);
214 fflush(stdout);
215
216 switch (fork()) {
217 case -1:
218 err(1, "fork");
219 break;
220 default:
221 if (wait(&status) < 0) {
222 warn("wait");
223 rval |= 1;
224 } else if (WIFSIGNALED(status)) {
225 fprintf(stderr, "%s: signal %d\n", *argv,
226 WTERMSIG(status));
227 rval |= 1;
228 } else if (WIFEXITED(status) &&
229 WEXITSTATUS(status) != 0) {
230 fprintf(stderr, "%s: exit status %d\n", *argv,
231 WEXITSTATUS(status));
232 rval |= 1;
233 }
234 break;
235 case 0:
236 if (is_shlib == 0) {
237 execl(*argv, *argv, (char *)NULL);
238 warn("%s", *argv);
239 } else if (fmt1 == NULL && fmt2 == NULL && !aflag) {
240 dlopen(*argv, RTLD_TRACE);
241 warnx("%s: %s", *argv, dlerror());
242 } else {
243 rtld = _PATH_RTLD;
244 #if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
245 if (type == TYPE_ELF32)
246 rtld = _COMPAT32_PATH_RTLD;
247 #endif
248 execl(rtld, rtld, "-d", "--",
249 *argv, (char *)NULL);
250 }
251 _exit(1);
252 }
253 }
254
255 return (rval);
256 }
257
258 static void
usage(void)259 usage(void)
260 {
261
262 fprintf(stderr, "usage: ldd [-a] [-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