1 | /* $NetBSD: linux_exec_elf32.c,v 1.93 2015/06/11 02:54:00 matt 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 | * |
20 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
22 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
23 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
24 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
30 | * POSSIBILITY OF SUCH DAMAGE. |
31 | */ |
32 | |
33 | /* |
34 | * based on exec_aout.c, sunos_exec.c and svr4_exec.c |
35 | */ |
36 | |
37 | #include <sys/cdefs.h> |
38 | __KERNEL_RCSID(0, "$NetBSD: linux_exec_elf32.c,v 1.93 2015/06/11 02:54:00 matt Exp $" ); |
39 | |
40 | #ifndef ELFSIZE |
41 | /* XXX should die */ |
42 | #define ELFSIZE 32 |
43 | #endif |
44 | |
45 | #include <sys/param.h> |
46 | #include <sys/systm.h> |
47 | #include <sys/kernel.h> |
48 | #include <sys/proc.h> |
49 | #include <sys/malloc.h> |
50 | #include <sys/namei.h> |
51 | #include <sys/vnode.h> |
52 | #include <sys/mount.h> |
53 | #include <sys/exec.h> |
54 | #include <sys/exec_elf.h> |
55 | #include <sys/stat.h> |
56 | #include <sys/kauth.h> |
57 | #include <sys/cprng.h> |
58 | |
59 | #include <sys/mman.h> |
60 | #include <sys/syscallargs.h> |
61 | |
62 | #include <sys/cpu.h> |
63 | #include <machine/reg.h> |
64 | |
65 | #include <compat/linux/common/linux_types.h> |
66 | #include <compat/linux/common/linux_signal.h> |
67 | #include <compat/linux/common/linux_util.h> |
68 | #include <compat/linux/common/linux_exec.h> |
69 | #include <compat/linux/common/linux_machdep.h> |
70 | #include <compat/linux/common/linux_ipc.h> |
71 | #include <compat/linux/common/linux_sem.h> |
72 | |
73 | #include <compat/linux/linux_syscallargs.h> |
74 | #include <compat/linux/linux_syscall.h> |
75 | |
76 | #ifdef DEBUG_LINUX |
77 | #define DPRINTF(a) uprintf a |
78 | #else |
79 | #define DPRINTF(a) |
80 | #endif |
81 | |
82 | #ifdef LINUX_ATEXIT_SIGNATURE |
83 | /* |
84 | * On the PowerPC, statically linked Linux binaries are not recognized |
85 | * by linux_signature nor by linux_gcc_signature. Fortunately, thoses |
86 | * binaries features a __libc_atexit ELF section. We therefore assume we |
87 | * have a Linux binary if we find this section. |
88 | */ |
89 | int |
90 | ELFNAME2(linux,atexit_signature)( |
91 | struct lwp *l, |
92 | struct exec_package *epp, |
93 | Elf_Ehdr *eh) |
94 | { |
95 | Elf_Shdr *sh; |
96 | size_t shsize; |
97 | u_int shstrndx; |
98 | size_t i; |
99 | static const char signature[] = "__libc_atexit" ; |
100 | const size_t sigsz = sizeof(signature); |
101 | char tbuf[sizeof(signature)]; |
102 | int error; |
103 | |
104 | /* Load the section header table. */ |
105 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
106 | sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); |
107 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
108 | if (error) |
109 | goto out; |
110 | |
111 | /* Now let's find the string table. If it does not exist, give up. */ |
112 | shstrndx = eh->e_shstrndx; |
113 | if (shstrndx == SHN_UNDEF || shstrndx >= eh->e_shnum) { |
114 | error = ENOEXEC; |
115 | goto out; |
116 | } |
117 | |
118 | /* Check if any section has the name we're looking for. */ |
119 | const off_t stroff = sh[shstrndx].sh_offset; |
120 | for (i = 0; i < eh->e_shnum; i++) { |
121 | Elf_Shdr *s = &sh[i]; |
122 | |
123 | if (s->sh_name + sigsz > sh[shstrndx].sh_size) |
124 | continue; |
125 | |
126 | error = exec_read_from(l, epp->ep_vp, stroff + s->sh_name, tbuf, |
127 | sigsz); |
128 | if (error) |
129 | goto out; |
130 | if (!memcmp(tbuf, signature, sigsz)) { |
131 | DPRINTF(("linux_atexit_sig=%s\n" , tbuf)); |
132 | error = 0; |
133 | goto out; |
134 | } |
135 | } |
136 | error = ENOEXEC; |
137 | |
138 | out: |
139 | free(sh, M_TEMP); |
140 | return (error); |
141 | } |
142 | #endif |
143 | |
144 | #ifdef LINUX_GCC_SIGNATURE |
145 | /* |
146 | * Take advantage of the fact that all the linux binaries are compiled |
147 | * with gcc, and gcc sticks in the comment field a signature. Note that |
148 | * on SVR4 binaries, the gcc signature will follow the OS name signature, |
149 | * that will not be a problem. We don't bother to read in the string table, |
150 | * but we check all the progbits headers. |
151 | * |
152 | * XXX This only works in the i386. On the alpha (at least) |
153 | * XXX we have the same gcc signature which incorrectly identifies |
154 | * XXX NetBSD binaries as Linux. |
155 | */ |
156 | int |
157 | ELFNAME2(linux,gcc_signature)( |
158 | struct lwp *l, |
159 | struct exec_package *epp, |
160 | Elf_Ehdr *eh) |
161 | { |
162 | size_t shsize; |
163 | size_t i; |
164 | static const char signature[] = "\0GCC: (GNU) " ; |
165 | char tbuf[sizeof(signature) - 1]; |
166 | Elf_Shdr *sh; |
167 | int error; |
168 | |
169 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
170 | sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); |
171 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
172 | if (error) |
173 | goto out; |
174 | |
175 | for (i = 0; i < eh->e_shnum; i++) { |
176 | Elf_Shdr *s = &sh[i]; |
177 | |
178 | /* |
179 | * Identify candidates for the comment header; |
180 | * Header cannot have a load address, or flags and |
181 | * it must be large enough. |
182 | */ |
183 | if (s->sh_type != SHT_PROGBITS || |
184 | s->sh_addr != 0 || |
185 | s->sh_flags != 0 || |
186 | s->sh_size < sizeof(signature) - 1) |
187 | continue; |
188 | |
189 | error = exec_read_from(l, epp->ep_vp, s->sh_offset, tbuf, |
190 | sizeof(signature) - 1); |
191 | if (error) |
192 | continue; |
193 | |
194 | /* |
195 | * error is 0, if the signatures match we are done. |
196 | */ |
197 | DPRINTF(("linux_gcc_sig: sig=%s\n" , tbuf)); |
198 | if (!memcmp(tbuf, signature, sizeof(signature) - 1)) { |
199 | error = 0; |
200 | goto out; |
201 | } |
202 | } |
203 | error = ENOEXEC; |
204 | |
205 | out: |
206 | free(sh, M_TEMP); |
207 | return (error); |
208 | } |
209 | #endif |
210 | |
211 | #ifdef LINUX_DEBUGLINK_SIGNATURE |
212 | /* |
213 | * Look for a .gnu_debuglink, specific to x86_64 interpreter |
214 | */ |
215 | int |
216 | ELFNAME2(linux,debuglink_signature)(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh) |
217 | { |
218 | Elf_Shdr *sh; |
219 | size_t shsize; |
220 | u_int shstrndx; |
221 | size_t i; |
222 | static const char signature[] = ".gnu_debuglink" ; |
223 | const size_t sigsz = sizeof(signature); |
224 | char tbuf[sizeof(signature)]; |
225 | int error; |
226 | |
227 | /* Load the section header table. */ |
228 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
229 | sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); |
230 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
231 | if (error) |
232 | goto out; |
233 | |
234 | /* Now let's find the string table. If it does not exist, give up. */ |
235 | shstrndx = eh->e_shstrndx; |
236 | if (shstrndx == SHN_UNDEF || shstrndx >= eh->e_shnum) { |
237 | error = ENOEXEC; |
238 | goto out; |
239 | } |
240 | |
241 | /* Check if any section has the name we're looking for. */ |
242 | const off_t stroff = sh[shstrndx].sh_offset; |
243 | for (i = 0; i < eh->e_shnum; i++) { |
244 | Elf_Shdr *s = &sh[i]; |
245 | |
246 | if (s->sh_name + sigsz > sh[shstrndx].sh_size) |
247 | continue; |
248 | |
249 | error = exec_read_from(l, epp->ep_vp, stroff + s->sh_name, tbuf, |
250 | sigsz); |
251 | if (error) |
252 | goto out; |
253 | if (!memcmp(tbuf, signature, sigsz)) { |
254 | DPRINTF(("linux_debuglink_sig=%s\n" , tbuf)); |
255 | error = 0; |
256 | goto out; |
257 | } |
258 | } |
259 | error = ENOEXEC; |
260 | |
261 | out: |
262 | free(sh, M_TEMP); |
263 | return (error); |
264 | } |
265 | #endif |
266 | |
267 | int |
268 | ELFNAME2(linux,signature)(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, char *itp) |
269 | { |
270 | size_t i; |
271 | Elf_Phdr *ph; |
272 | size_t phsize; |
273 | int error; |
274 | static const char linux[] = "Linux" ; |
275 | |
276 | if (eh->e_ident[EI_OSABI] == 3 || |
277 | memcmp(&eh->e_ident[EI_ABIVERSION], linux, sizeof(linux)) == 0) |
278 | return 0; |
279 | |
280 | phsize = eh->e_phnum * sizeof(Elf_Phdr); |
281 | ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); |
282 | error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); |
283 | if (error) |
284 | goto out; |
285 | |
286 | for (i = 0; i < eh->e_phnum; i++) { |
287 | Elf_Phdr *ephp = &ph[i]; |
288 | Elf_Nhdr *np; |
289 | u_int32_t *abi; |
290 | |
291 | if (ephp->p_type != PT_NOTE || |
292 | ephp->p_filesz > 1024 || |
293 | ephp->p_filesz < sizeof(Elf_Nhdr) + 20) |
294 | continue; |
295 | |
296 | np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); |
297 | error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, |
298 | ephp->p_filesz); |
299 | if (error) |
300 | goto next; |
301 | |
302 | if (np->n_type != ELF_NOTE_TYPE_ABI_TAG || |
303 | np->n_namesz != ELF_NOTE_ABI_NAMESZ || |
304 | np->n_descsz != ELF_NOTE_ABI_DESCSZ || |
305 | memcmp((void *)(np + 1), ELF_NOTE_ABI_NAME, |
306 | ELF_NOTE_ABI_NAMESZ)) |
307 | goto next; |
308 | |
309 | /* Make sure the OS is Linux. */ |
310 | abi = (u_int32_t *)((char *)np + sizeof(Elf_Nhdr) + |
311 | np->n_namesz); |
312 | if (abi[0] == ELF_NOTE_ABI_OS_LINUX) |
313 | error = 0; |
314 | else |
315 | error = ENOEXEC; |
316 | free(np, M_TEMP); |
317 | goto out; |
318 | |
319 | next: |
320 | free(np, M_TEMP); |
321 | continue; |
322 | } |
323 | |
324 | /* Check for certain interpreter names. */ |
325 | if (itp) { |
326 | if (!strncmp(itp, "/lib/ld-linux" , 13) || |
327 | #if (ELFSIZE == 64) |
328 | !strncmp(itp, "/lib64/ld-linux" , 15) || |
329 | #endif |
330 | !strncmp(itp, "/lib/ld.so." , 11)) |
331 | error = 0; |
332 | else |
333 | error = ENOEXEC; |
334 | goto out; |
335 | } |
336 | |
337 | error = ENOEXEC; |
338 | out: |
339 | free(ph, M_TEMP); |
340 | return (error); |
341 | } |
342 | |
343 | int |
344 | ELFNAME2(linux,probe)(struct lwp *l, struct exec_package *epp, void *eh, |
345 | char *itp, vaddr_t *pos) |
346 | { |
347 | int error; |
348 | |
349 | if (((error = ELFNAME2(linux,signature)(l, epp, eh, itp)) != 0) && |
350 | #ifdef LINUX_GCC_SIGNATURE |
351 | ((error = ELFNAME2(linux,gcc_signature)(l, epp, eh)) != 0) && |
352 | #endif |
353 | #ifdef LINUX_ATEXIT_SIGNATURE |
354 | ((error = ELFNAME2(linux,atexit_signature)(l, epp, eh)) != 0) && |
355 | #endif |
356 | #ifdef LINUX_DEBUGLINK_SIGNATURE |
357 | ((error = ELFNAME2(linux,debuglink_signature)(l, epp, eh)) != 0) && |
358 | #endif |
359 | 1) { |
360 | DPRINTF(("linux_probe: returning %d\n" , error)); |
361 | return error; |
362 | } |
363 | |
364 | if (itp) { |
365 | if ((error = emul_find_interp(l, epp, itp))) |
366 | return (error); |
367 | } |
368 | epp->ep_flags |= EXEC_FORCEAUX; |
369 | DPRINTF(("linux_probe: returning 0\n" )); |
370 | return 0; |
371 | } |
372 | |
373 | #ifndef LINUX_MACHDEP_ELF_COPYARGS |
374 | /* |
375 | * Copy arguments onto the stack in the normal way, but add some |
376 | * extra information in case of dynamic binding. |
377 | */ |
378 | int |
379 | ELFNAME2(linux,copyargs)(struct lwp *l, struct exec_package *pack, |
380 | struct ps_strings *arginfo, char **stackp, void *argp) |
381 | { |
382 | size_t len; |
383 | AuxInfo ai[LINUX_ELF_AUX_ENTRIES], *a; |
384 | struct elf_args *ap; |
385 | int error; |
386 | struct vattr *vap; |
387 | uint32_t randbytes[4]; |
388 | |
389 | if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) |
390 | return error; |
391 | |
392 | a = ai; |
393 | |
394 | memset(ai, 0, sizeof(ai)); |
395 | |
396 | /* |
397 | * Push extra arguments used by glibc on the stack. |
398 | */ |
399 | |
400 | a->a_type = AT_PAGESZ; |
401 | a->a_v = PAGE_SIZE; |
402 | a++; |
403 | |
404 | if ((ap = (struct elf_args *)pack->ep_emul_arg)) { |
405 | |
406 | a->a_type = AT_PHDR; |
407 | a->a_v = ap->arg_phaddr; |
408 | a++; |
409 | |
410 | a->a_type = AT_PHENT; |
411 | a->a_v = ap->arg_phentsize; |
412 | a++; |
413 | |
414 | a->a_type = AT_PHNUM; |
415 | a->a_v = ap->arg_phnum; |
416 | a++; |
417 | |
418 | a->a_type = AT_BASE; |
419 | a->a_v = ap->arg_interp; |
420 | a++; |
421 | |
422 | a->a_type = AT_FLAGS; |
423 | a->a_v = 0; |
424 | a++; |
425 | |
426 | a->a_type = AT_ENTRY; |
427 | a->a_v = ap->arg_entry; |
428 | a++; |
429 | |
430 | exec_free_emul_arg(pack); |
431 | } |
432 | |
433 | /* Linux-specific items */ |
434 | a->a_type = LINUX_AT_CLKTCK; |
435 | a->a_v = hz; |
436 | a++; |
437 | |
438 | vap = pack->ep_vap; |
439 | |
440 | a->a_type = LINUX_AT_UID; |
441 | a->a_v = kauth_cred_getuid(l->l_cred); |
442 | a++; |
443 | |
444 | a->a_type = LINUX_AT_EUID; |
445 | if (vap->va_mode & S_ISUID) |
446 | a->a_v = vap->va_uid; |
447 | else |
448 | a->a_v = kauth_cred_geteuid(l->l_cred); |
449 | a++; |
450 | |
451 | a->a_type = LINUX_AT_GID; |
452 | a->a_v = kauth_cred_getgid(l->l_cred); |
453 | a++; |
454 | |
455 | a->a_type = LINUX_AT_EGID; |
456 | if (vap->va_mode & S_ISGID) |
457 | a->a_v = vap->va_gid; |
458 | else |
459 | a->a_v = kauth_cred_getegid(l->l_cred); |
460 | a++; |
461 | |
462 | a->a_type = LINUX_AT_RANDOM; |
463 | a->a_v = (Elf_Addr)(uintptr_t)*stackp; |
464 | a++; |
465 | |
466 | a->a_type = AT_NULL; |
467 | a->a_v = 0; |
468 | a++; |
469 | |
470 | randbytes[0] = cprng_strong32(); |
471 | randbytes[1] = cprng_strong32(); |
472 | randbytes[2] = cprng_strong32(); |
473 | randbytes[3] = cprng_strong32(); |
474 | |
475 | len = sizeof(randbytes); |
476 | if ((error = copyout(randbytes, *stackp, len)) != 0) |
477 | return error; |
478 | *stackp += len; |
479 | |
480 | len = (a - ai) * sizeof(AuxInfo); |
481 | KASSERT(len <= LINUX_ELF_AUX_ENTRIES * sizeof(AuxInfo)); |
482 | if ((error = copyout(ai, *stackp, len)) != 0) |
483 | return error; |
484 | *stackp += len; |
485 | |
486 | return 0; |
487 | } |
488 | #endif /* !LINUX_MACHDEP_ELF_COPYARGS */ |
489 | |