linux_exec_elf32.c revision 1.69.2.5 1 /* $NetBSD: linux_exec_elf32.c,v 1.69.2.5 2007/10/27 11:29:35 yamt Exp $ */
2
3 /*-
4 * Copyright (c) 1995, 1998, 2000, 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas, Frank van der Linden, Eric Haszlakiewicz and
9 * Emmanuel Dreyfus.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 /*
41 * based on exec_aout.c, sunos_exec.c and svr4_exec.c
42 */
43
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: linux_exec_elf32.c,v 1.69.2.5 2007/10/27 11:29:35 yamt Exp $");
46
47 #ifndef ELFSIZE
48 /* XXX should die */
49 #define ELFSIZE 32
50 #endif
51
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/kernel.h>
55 #include <sys/proc.h>
56 #include <sys/malloc.h>
57 #include <sys/namei.h>
58 #include <sys/vnode.h>
59 #include <sys/mount.h>
60 #include <sys/exec.h>
61 #include <sys/exec_elf.h>
62 #include <sys/stat.h>
63 #include <sys/kauth.h>
64
65 #include <sys/mman.h>
66 #include <sys/syscallargs.h>
67
68 #include <sys/cpu.h>
69 #include <machine/reg.h>
70
71 #include <compat/linux/common/linux_types.h>
72 #include <compat/linux/common/linux_signal.h>
73 #include <compat/linux/common/linux_util.h>
74 #include <compat/linux/common/linux_exec.h>
75 #include <compat/linux/common/linux_machdep.h>
76
77 #include <compat/linux/linux_syscallargs.h>
78 #include <compat/linux/linux_syscall.h>
79
80 #ifdef DEBUG_LINUX
81 #define DPRINTF(a) uprintf a
82 #else
83 #define DPRINTF(a)
84 #endif
85
86 #ifdef LINUX_ATEXIT_SIGNATURE
87 /*
88 * On the PowerPC, statically linked Linux binaries are not recognized
89 * by linux_signature nor by linux_gcc_signature. Fortunately, thoses
90 * binaries features a __libc_atexit ELF section. We therefore assume we
91 * have a Linux binary if we find this section.
92 */
93 int
94 ELFNAME2(linux,atexit_signature)(l, epp, eh)
95 struct lwp *l;
96 struct exec_package *epp;
97 Elf_Ehdr *eh;
98 {
99 size_t shsize;
100 int strndx;
101 size_t i;
102 static const char signature[] = "__libc_atexit";
103 char *strtable = NULL;
104 Elf_Shdr *sh;
105
106 int error;
107
108 /*
109 * load the section header table
110 */
111 shsize = eh->e_shnum * sizeof(Elf_Shdr);
112 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK);
113 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize);
114 if (error)
115 goto out;
116
117 /*
118 * Now let's find the string table. If it does not exists, give up.
119 */
120 strndx = (int)(eh->e_shstrndx);
121 if (strndx == SHN_UNDEF) {
122 error = ENOEXEC;
123 goto out;
124 }
125
126 /*
127 * strndx is the index in section header table of the string table
128 * section get the whole string table in strtable, and then we get access to the names
129 * s->sh_name is the offset of the section name in strtable.
130 */
131 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK);
132 error = exec_read_from(l, epp->ep_vp, sh[strndx].sh_offset, strtable,
133 sh[strndx].sh_size);
134 if (error)
135 goto out;
136
137 for (i = 0; i < eh->e_shnum; i++) {
138 Elf_Shdr *s = &sh[i];
139 if (!memcmp((void*)(&(strtable[s->sh_name])), signature,
140 sizeof(signature))) {
141 DPRINTF(("linux_atexit_sig=%s\n",
142 &(strtable[s->sh_name])));
143 error = 0;
144 goto out;
145 }
146 }
147 error = ENOEXEC;
148
149 out:
150 free(sh, M_TEMP);
151 if (strtable)
152 free(strtable, M_TEMP);
153 return (error);
154 }
155 #endif
156
157 #ifdef LINUX_GCC_SIGNATURE
158 /*
159 * Take advantage of the fact that all the linux binaries are compiled
160 * with gcc, and gcc sticks in the comment field a signature. Note that
161 * on SVR4 binaries, the gcc signature will follow the OS name signature,
162 * that will not be a problem. We don't bother to read in the string table,
163 * but we check all the progbits headers.
164 *
165 * XXX This only works in the i386. On the alpha (at least)
166 * XXX we have the same gcc signature which incorrectly identifies
167 * XXX NetBSD binaries as Linux.
168 */
169 int
170 ELFNAME2(linux,gcc_signature)(l, epp, eh)
171 struct lwp *l;
172 struct exec_package *epp;
173 Elf_Ehdr *eh;
174 {
175 size_t shsize;
176 size_t i;
177 static const char signature[] = "\0GCC: (GNU) ";
178 char tbuf[sizeof(signature) - 1];
179 Elf_Shdr *sh;
180 int error;
181
182 shsize = eh->e_shnum * sizeof(Elf_Shdr);
183 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK);
184 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize);
185 if (error)
186 goto out;
187
188 for (i = 0; i < eh->e_shnum; i++) {
189 Elf_Shdr *s = &sh[i];
190
191 /*
192 * Identify candidates for the comment header;
193 * Header cannot have a load address, or flags and
194 * it must be large enough.
195 */
196 if (s->sh_type != SHT_PROGBITS ||
197 s->sh_addr != 0 ||
198 s->sh_flags != 0 ||
199 s->sh_size < sizeof(signature) - 1)
200 continue;
201
202 error = exec_read_from(l, epp->ep_vp, s->sh_offset, tbuf,
203 sizeof(signature) - 1);
204 if (error)
205 continue;
206
207 /*
208 * error is 0, if the signatures match we are done.
209 */
210 DPRINTF(("linux_gcc_sig: sig=%s\n", tbuf));
211 if (!memcmp(tbuf, signature, sizeof(signature) - 1)) {
212 error = 0;
213 goto out;
214 }
215 }
216 error = ENOEXEC;
217
218 out:
219 free(sh, M_TEMP);
220 return (error);
221 }
222 #endif
223
224 #ifdef LINUX_DEBUGLINK_SIGNATURE
225 /*
226 * Look for a .gnu_debuglink, specific to x86_64 interpeter
227 */
228 int
229 ELFNAME2(linux,debuglink_signature)(l, epp, eh)
230 struct lwp *l;
231 struct exec_package *epp;
232 Elf_Ehdr *eh;
233 {
234 size_t shsize;
235 int strndx;
236 size_t i;
237 static const char signature[] = ".gnu_debuglink";
238 char *strtable = NULL;
239 Elf_Shdr *sh;
240
241 int error;
242
243 /*
244 * load the section header table
245 */
246 shsize = eh->e_shnum * sizeof(Elf_Shdr);
247 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK);
248 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize);
249 if (error)
250 goto out;
251
252 /*
253 * Now let's find the string table. If it does not exists, give up.
254 */
255 strndx = (int)(eh->e_shstrndx);
256 if (strndx == SHN_UNDEF) {
257 error = ENOEXEC;
258 goto out;
259 }
260
261 /*
262 * strndx is the index in section header table of the string table
263 * section get the whole string table in strtable, and then we get access to the names
264 * s->sh_name is the offset of the section name in strtable.
265 */
266 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK);
267 error = exec_read_from(l, epp->ep_vp, sh[strndx].sh_offset, strtable,
268 sh[strndx].sh_size);
269 if (error)
270 goto out;
271
272 for (i = 0; i < eh->e_shnum; i++) {
273 Elf_Shdr *s = &sh[i];
274
275 if (!memcmp((void*)(&(strtable[s->sh_name])), signature,
276 sizeof(signature))) {
277 DPRINTF(("linux_debuglink_sig=%s\n",
278 &(strtable[s->sh_name])));
279 error = 0;
280 goto out;
281 }
282 }
283 error = ENOEXEC;
284
285 out:
286 free(sh, M_TEMP);
287 if (strtable)
288 free(strtable, M_TEMP);
289 return (error);
290 }
291 #endif
292
293 int
294 ELFNAME2(linux,signature)(l, epp, eh, itp)
295 struct lwp *l;
296 struct exec_package *epp;
297 Elf_Ehdr *eh;
298 char *itp;
299 {
300 size_t i;
301 Elf_Phdr *ph;
302 size_t phsize;
303 int error;
304 static const char linux[] = "Linux";
305
306 if (eh->e_ident[EI_OSABI] == 3 ||
307 memcmp(&eh->e_ident[EI_ABIVERSION], linux, sizeof(linux)) == 0)
308 return 0;
309
310 phsize = eh->e_phnum * sizeof(Elf_Phdr);
311 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
312 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize);
313 if (error)
314 goto out;
315
316 for (i = 0; i < eh->e_phnum; i++) {
317 Elf_Phdr *ephp = &ph[i];
318 Elf_Nhdr *np;
319 u_int32_t *abi;
320
321 if (ephp->p_type != PT_NOTE ||
322 ephp->p_filesz > 1024 ||
323 ephp->p_filesz < sizeof(Elf_Nhdr) + 20)
324 continue;
325
326 np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK);
327 error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np,
328 ephp->p_filesz);
329 if (error)
330 goto next;
331
332 if (np->n_type != ELF_NOTE_TYPE_ABI_TAG ||
333 np->n_namesz != ELF_NOTE_ABI_NAMESZ ||
334 np->n_descsz != ELF_NOTE_ABI_DESCSZ ||
335 memcmp((void *)(np + 1), ELF_NOTE_ABI_NAME,
336 ELF_NOTE_ABI_NAMESZ))
337 goto next;
338
339 /* Make sure the OS is Linux. */
340 abi = (u_int32_t *)((char *)np + sizeof(Elf_Nhdr) +
341 np->n_namesz);
342 if (abi[0] == ELF_NOTE_ABI_OS_LINUX)
343 error = 0;
344 else
345 error = ENOEXEC;
346 free(np, M_TEMP);
347 goto out;
348
349 next:
350 free(np, M_TEMP);
351 continue;
352 }
353
354 /* Check for certain intepreter names. */
355 if (itp) {
356 if (!strncmp(itp, "/lib/ld-linux", 13) ||
357 #if (ELFSIZE == 64)
358 !strncmp(itp, "/lib64/ld-linux", 15) ||
359 #endif
360 !strncmp(itp, "/lib/ld.so.", 11))
361 error = 0;
362 else
363 error = ENOEXEC;
364 goto out;
365 }
366
367 error = ENOEXEC;
368 out:
369 free(ph, M_TEMP);
370 return (error);
371 }
372
373 int
374 ELFNAME2(linux,probe)(struct lwp *l, struct exec_package *epp, void *eh,
375 char *itp, vaddr_t *pos)
376 {
377 int error;
378
379 if (((error = ELFNAME2(linux,signature)(l, epp, eh, itp)) != 0) &&
380 #ifdef LINUX_GCC_SIGNATURE
381 ((error = ELFNAME2(linux,gcc_signature)(l, epp, eh)) != 0) &&
382 #endif
383 #ifdef LINUX_ATEXIT_SIGNATURE
384 ((error = ELFNAME2(linux,atexit_signature)(l, epp, eh)) != 0) &&
385 #endif
386 #ifdef LINUX_DEBUGLINK_SIGNATURE
387 ((error = ELFNAME2(linux,debuglink_signature)(l, epp, eh)) != 0) &&
388 #endif
389 1) {
390 DPRINTF(("linux_probe: returning %d\n", error));
391 return error;
392 }
393
394 if (itp) {
395 if ((error = emul_find_interp(l, epp, itp)))
396 return (error);
397 }
398 DPRINTF(("linux_probe: returning 0\n"));
399 return 0;
400 }
401
402 #ifndef LINUX_MACHDEP_ELF_COPYARGS
403 /*
404 * Copy arguments onto the stack in the normal way, but add some
405 * extra information in case of dynamic binding.
406 */
407 int
408 ELFNAME2(linux,copyargs)(struct lwp *l, struct exec_package *pack,
409 struct ps_strings *arginfo, char **stackp, void *argp)
410 {
411 size_t len;
412 AuxInfo ai[LINUX_ELF_AUX_ENTRIES], *a;
413 struct elf_args *ap;
414 int error;
415 struct vattr *vap;
416
417 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0)
418 return error;
419
420 a = ai;
421
422 /*
423 * Push extra arguments used by glibc on the stack.
424 */
425
426 a->a_type = AT_PAGESZ;
427 a->a_v = PAGE_SIZE;
428 a++;
429
430 if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
431
432 a->a_type = AT_PHDR;
433 a->a_v = ap->arg_phaddr;
434 a++;
435
436 a->a_type = AT_PHENT;
437 a->a_v = ap->arg_phentsize;
438 a++;
439
440 a->a_type = AT_PHNUM;
441 a->a_v = ap->arg_phnum;
442 a++;
443
444 a->a_type = AT_BASE;
445 a->a_v = ap->arg_interp;
446 a++;
447
448 a->a_type = AT_FLAGS;
449 a->a_v = 0;
450 a++;
451
452 a->a_type = AT_ENTRY;
453 a->a_v = ap->arg_entry;
454 a++;
455
456 free(pack->ep_emul_arg, M_TEMP);
457 pack->ep_emul_arg = NULL;
458 }
459
460 /* Linux-specific items */
461 a->a_type = LINUX_AT_CLKTCK;
462 a->a_v = hz;
463 a++;
464
465 vap = pack->ep_vap;
466
467 a->a_type = LINUX_AT_UID;
468 a->a_v = kauth_cred_getuid(l->l_cred);
469 a++;
470
471 a->a_type = LINUX_AT_EUID;
472 if (vap->va_mode & S_ISUID)
473 a->a_v = vap->va_uid;
474 else
475 a->a_v = kauth_cred_geteuid(l->l_cred);
476 a++;
477
478 a->a_type = LINUX_AT_GID;
479 a->a_v = kauth_cred_getgid(l->l_cred);
480 a++;
481
482 a->a_type = LINUX_AT_EGID;
483 if (vap->va_mode & S_ISGID)
484 a->a_v = vap->va_gid;
485 else
486 a->a_v = kauth_cred_getegid(l->l_cred);
487 a++;
488
489 a->a_type = AT_NULL;
490 a->a_v = 0;
491 a++;
492
493 len = (a - ai) * sizeof(AuxInfo);
494 if ((error = copyout(ai, *stackp, len)) != 0)
495 return error;
496 *stackp += len;
497
498 return 0;
499 }
500 #endif /* !LINUX_MACHDEP_ELF_COPYARGS */
501