1 | /* $NetBSD: exec_elf.c,v 1.87 2016/09/15 18:40:34 christos Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 1994, 2000, 2005, 2015 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 and Maxime Villard. |
9 | * |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions |
12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | /* |
33 | * Copyright (c) 1996 Christopher G. Demetriou |
34 | * All rights reserved. |
35 | * |
36 | * Redistribution and use in source and binary forms, with or without |
37 | * modification, are permitted provided that the following conditions |
38 | * are met: |
39 | * 1. Redistributions of source code must retain the above copyright |
40 | * notice, this list of conditions and the following disclaimer. |
41 | * 2. Redistributions in binary form must reproduce the above copyright |
42 | * notice, this list of conditions and the following disclaimer in the |
43 | * documentation and/or other materials provided with the distribution. |
44 | * 3. The name of the author may not be used to endorse or promote products |
45 | * derived from this software without specific prior written permission |
46 | * |
47 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
48 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
49 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
50 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
51 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
52 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
53 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
54 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
55 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
56 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
57 | */ |
58 | |
59 | #include <sys/cdefs.h> |
60 | __KERNEL_RCSID(1, "$NetBSD: exec_elf.c,v 1.87 2016/09/15 18:40:34 christos Exp $" ); |
61 | |
62 | #ifdef _KERNEL_OPT |
63 | #include "opt_pax.h" |
64 | #endif /* _KERNEL_OPT */ |
65 | |
66 | #include <sys/param.h> |
67 | #include <sys/proc.h> |
68 | #include <sys/kmem.h> |
69 | #include <sys/namei.h> |
70 | #include <sys/vnode.h> |
71 | #include <sys/exec.h> |
72 | #include <sys/exec_elf.h> |
73 | #include <sys/syscall.h> |
74 | #include <sys/signalvar.h> |
75 | #include <sys/mount.h> |
76 | #include <sys/stat.h> |
77 | #include <sys/kauth.h> |
78 | #include <sys/bitops.h> |
79 | |
80 | #include <sys/cpu.h> |
81 | #include <machine/reg.h> |
82 | |
83 | #include <compat/common/compat_util.h> |
84 | |
85 | #include <sys/pax.h> |
86 | #include <uvm/uvm_param.h> |
87 | |
88 | extern struct emul emul_netbsd; |
89 | |
90 | #define ELFNAME(check_header) |
91 | #define elf_copyargs ELFNAME(copyargs) |
92 | #define elf_load_interp ELFNAME(load_interp) |
93 | #define elf_load_psection ELFNAME(load_psection) |
94 | #define exec_elf_makecmds ELFNAME2(exec,makecmds) |
95 | #define netbsd_elf_signature ELFNAME2(netbsd,signature) |
96 | #define netbsd_elf_probe ELFNAME2(netbsd,probe) |
97 | #define coredump ELFNAMEEND(coredump) |
98 | #define elf_free_emul_arg ELFNAME(free_emul_arg) |
99 | |
100 | static int |
101 | elf_load_interp(struct lwp *, struct exec_package *, char *, |
102 | struct exec_vmcmd_set *, u_long *, Elf_Addr *); |
103 | static void |
104 | elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *, |
105 | Elf_Addr *, u_long *, int); |
106 | |
107 | int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); |
108 | int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, |
109 | vaddr_t *); |
110 | |
111 | static void elf_free_emul_arg(void *); |
112 | |
113 | #ifdef DEBUG_ELF |
114 | #define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__) |
115 | #else |
116 | #define DPRINTF(a, ...) |
117 | #endif |
118 | |
119 | /* round up and down to page boundaries. */ |
120 | #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) |
121 | #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) |
122 | |
123 | static void |
124 | elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph) |
125 | { |
126 | Elf_Addr align, offset; |
127 | int i; |
128 | |
129 | for (align = i = 0; i < eh->e_phnum; i++) |
130 | if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) |
131 | align = ph[i].p_align; |
132 | |
133 | offset = (Elf_Addr)pax_aslr_exec_offset(epp, align); |
134 | offset += epp->ep_vm_minaddr; |
135 | |
136 | for (i = 0; i < eh->e_phnum; i++) |
137 | ph[i].p_vaddr += offset; |
138 | epp->ep_entryoffset = offset; |
139 | eh->e_entry += offset; |
140 | } |
141 | |
142 | /* |
143 | * Copy arguments onto the stack in the normal way, but add some |
144 | * extra information in case of dynamic binding. |
145 | */ |
146 | int |
147 | elf_copyargs(struct lwp *l, struct exec_package *pack, |
148 | struct ps_strings *arginfo, char **stackp, void *argp) |
149 | { |
150 | size_t len, vlen; |
151 | AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; |
152 | struct elf_args *ap; |
153 | int error; |
154 | |
155 | if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) |
156 | return error; |
157 | |
158 | a = ai; |
159 | execname = NULL; |
160 | |
161 | memset(ai, 0, sizeof(ai)); |
162 | |
163 | /* |
164 | * Push extra arguments on the stack needed by dynamically |
165 | * linked binaries |
166 | */ |
167 | if ((ap = (struct elf_args *)pack->ep_emul_arg)) { |
168 | struct vattr *vap = pack->ep_vap; |
169 | |
170 | a->a_type = AT_PHDR; |
171 | a->a_v = ap->arg_phaddr; |
172 | a++; |
173 | |
174 | a->a_type = AT_PHENT; |
175 | a->a_v = ap->arg_phentsize; |
176 | a++; |
177 | |
178 | a->a_type = AT_PHNUM; |
179 | a->a_v = ap->arg_phnum; |
180 | a++; |
181 | |
182 | a->a_type = AT_PAGESZ; |
183 | a->a_v = PAGE_SIZE; |
184 | a++; |
185 | |
186 | a->a_type = AT_BASE; |
187 | a->a_v = ap->arg_interp; |
188 | a++; |
189 | |
190 | a->a_type = AT_FLAGS; |
191 | a->a_v = 0; |
192 | a++; |
193 | |
194 | a->a_type = AT_ENTRY; |
195 | a->a_v = ap->arg_entry; |
196 | a++; |
197 | |
198 | a->a_type = AT_EUID; |
199 | if (vap->va_mode & S_ISUID) |
200 | a->a_v = vap->va_uid; |
201 | else |
202 | a->a_v = kauth_cred_geteuid(l->l_cred); |
203 | a++; |
204 | |
205 | a->a_type = AT_RUID; |
206 | a->a_v = kauth_cred_getuid(l->l_cred); |
207 | a++; |
208 | |
209 | a->a_type = AT_EGID; |
210 | if (vap->va_mode & S_ISGID) |
211 | a->a_v = vap->va_gid; |
212 | else |
213 | a->a_v = kauth_cred_getegid(l->l_cred); |
214 | a++; |
215 | |
216 | a->a_type = AT_RGID; |
217 | a->a_v = kauth_cred_getgid(l->l_cred); |
218 | a++; |
219 | |
220 | a->a_type = AT_STACKBASE; |
221 | a->a_v = l->l_proc->p_stackbase; |
222 | a++; |
223 | |
224 | if (pack->ep_path) { |
225 | execname = a; |
226 | a->a_type = AT_SUN_EXECNAME; |
227 | a++; |
228 | } |
229 | |
230 | exec_free_emul_arg(pack); |
231 | } |
232 | |
233 | a->a_type = AT_NULL; |
234 | a->a_v = 0; |
235 | a++; |
236 | |
237 | vlen = (a - ai) * sizeof(ai[0]); |
238 | |
239 | KASSERT(vlen <= sizeof(ai)); |
240 | |
241 | if (execname) { |
242 | char *path = pack->ep_path; |
243 | execname->a_v = (uintptr_t)(*stackp + vlen); |
244 | len = strlen(path) + 1; |
245 | if ((error = copyout(path, (*stackp + vlen), len)) != 0) |
246 | return error; |
247 | len = ALIGN(len); |
248 | } else |
249 | len = 0; |
250 | |
251 | if ((error = copyout(ai, *stackp, vlen)) != 0) |
252 | return error; |
253 | *stackp += vlen + len; |
254 | |
255 | return 0; |
256 | } |
257 | |
258 | /* |
259 | * elf_check_header(): |
260 | * |
261 | * Check header for validity; return 0 if ok, ENOEXEC if error |
262 | */ |
263 | int |
264 | elf_check_header(Elf_Ehdr *eh) |
265 | { |
266 | |
267 | if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || |
268 | eh->e_ident[EI_CLASS] != ELFCLASS) { |
269 | DPRINTF("bad magic %#x%x%x" , eh->e_ident[0], eh->e_ident[1], |
270 | eh->e_ident[2]); |
271 | return ENOEXEC; |
272 | } |
273 | |
274 | switch (eh->e_machine) { |
275 | |
276 | ELFDEFNNAME(MACHDEP_ID_CASES) |
277 | |
278 | default: |
279 | DPRINTF("bad machine %#x" , eh->e_machine); |
280 | return ENOEXEC; |
281 | } |
282 | |
283 | if (ELF_EHDR_FLAGS_OK(eh) == 0) { |
284 | DPRINTF("bad flags %#x" , eh->e_flags); |
285 | return ENOEXEC; |
286 | } |
287 | |
288 | if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) { |
289 | DPRINTF("bad shnum/phnum %#x/%#x" , eh->e_shnum, eh->e_phnum); |
290 | return ENOEXEC; |
291 | } |
292 | |
293 | return 0; |
294 | } |
295 | |
296 | /* |
297 | * elf_load_psection(): |
298 | * |
299 | * Load a psection at the appropriate address |
300 | */ |
301 | static void |
302 | elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, |
303 | const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags) |
304 | { |
305 | u_long msize, psize, rm, rf; |
306 | long diff, offset; |
307 | int vmprot = 0; |
308 | |
309 | /* |
310 | * If the user specified an address, then we load there. |
311 | */ |
312 | if (*addr == ELFDEFNNAME(NO_ADDR)) |
313 | *addr = ph->p_vaddr; |
314 | |
315 | if (ph->p_align > 1) { |
316 | /* |
317 | * Make sure we are virtually aligned as we are supposed to be. |
318 | */ |
319 | diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); |
320 | KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); |
321 | /* |
322 | * But make sure to not map any pages before the start of the |
323 | * psection by limiting the difference to within a page. |
324 | */ |
325 | diff &= PAGE_MASK; |
326 | } else |
327 | diff = 0; |
328 | |
329 | vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; |
330 | vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; |
331 | vmprot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; |
332 | |
333 | /* |
334 | * Adjust everything so it all starts on a page boundary. |
335 | */ |
336 | *addr -= diff; |
337 | offset = ph->p_offset - diff; |
338 | *size = ph->p_filesz + diff; |
339 | msize = ph->p_memsz + diff; |
340 | |
341 | if (ph->p_align >= PAGE_SIZE) { |
342 | if ((ph->p_flags & PF_W) != 0) { |
343 | /* |
344 | * Because the pagedvn pager can't handle zero fill |
345 | * of the last data page if it's not page aligned we |
346 | * map the last page readvn. |
347 | */ |
348 | psize = trunc_page(*size); |
349 | } else { |
350 | psize = round_page(*size); |
351 | } |
352 | } else { |
353 | psize = *size; |
354 | } |
355 | |
356 | if (psize > 0) { |
357 | NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? |
358 | vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, |
359 | offset, vmprot, flags); |
360 | flags &= VMCMD_RELATIVE; |
361 | } |
362 | if (psize < *size) { |
363 | NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, |
364 | *addr + psize, vp, offset + psize, vmprot, flags); |
365 | } |
366 | |
367 | /* |
368 | * Check if we need to extend the size of the segment (does |
369 | * bss extend page the next page boundary)? |
370 | */ |
371 | rm = round_page(*addr + msize); |
372 | rf = round_page(*addr + *size); |
373 | |
374 | if (rm != rf) { |
375 | NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, |
376 | 0, vmprot, flags & VMCMD_RELATIVE); |
377 | *size = msize; |
378 | } |
379 | } |
380 | |
381 | /* |
382 | * elf_load_interp(): |
383 | * |
384 | * Load an interpreter pointed to by path. |
385 | */ |
386 | static int |
387 | elf_load_interp(struct lwp *l, struct exec_package *epp, char *path, |
388 | struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last) |
389 | { |
390 | int error, i; |
391 | struct vnode *vp; |
392 | struct vattr attr; |
393 | Elf_Ehdr eh; |
394 | Elf_Phdr *ph = NULL; |
395 | const Elf_Phdr *base_ph; |
396 | const Elf_Phdr *last_ph; |
397 | u_long phsize; |
398 | Elf_Addr addr = *last; |
399 | struct proc *p; |
400 | bool use_topdown; |
401 | |
402 | p = l->l_proc; |
403 | |
404 | KASSERT(p->p_vmspace); |
405 | KASSERT(p->p_vmspace != proc0.p_vmspace); |
406 | |
407 | #ifdef __USE_TOPDOWN_VM |
408 | use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM; |
409 | #else |
410 | use_topdown = false; |
411 | #endif |
412 | |
413 | /* |
414 | * 1. open file |
415 | * 2. read filehdr |
416 | * 3. map text, data, and bss out of it using VM_* |
417 | */ |
418 | vp = epp->ep_interp; |
419 | if (vp == NULL) { |
420 | error = emul_find_interp(l, epp, path); |
421 | if (error != 0) |
422 | return error; |
423 | vp = epp->ep_interp; |
424 | } |
425 | /* We'll tidy this ourselves - otherwise we have locking issues */ |
426 | epp->ep_interp = NULL; |
427 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); |
428 | |
429 | /* |
430 | * Similarly, if it's not marked as executable, or it's not a regular |
431 | * file, we don't allow it to be used. |
432 | */ |
433 | if (vp->v_type != VREG) { |
434 | error = EACCES; |
435 | goto badunlock; |
436 | } |
437 | if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) |
438 | goto badunlock; |
439 | |
440 | /* get attributes */ |
441 | if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) |
442 | goto badunlock; |
443 | |
444 | /* |
445 | * Check mount point. Though we're not trying to exec this binary, |
446 | * we will be executing code from it, so if the mount point |
447 | * disallows execution or set-id-ness, we punt or kill the set-id. |
448 | */ |
449 | if (vp->v_mount->mnt_flag & MNT_NOEXEC) { |
450 | error = EACCES; |
451 | goto badunlock; |
452 | } |
453 | if (vp->v_mount->mnt_flag & MNT_NOSUID) |
454 | epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); |
455 | |
456 | error = vn_marktext(vp); |
457 | if (error) |
458 | goto badunlock; |
459 | |
460 | VOP_UNLOCK(vp); |
461 | |
462 | if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) |
463 | goto bad; |
464 | |
465 | if ((error = elf_check_header(&eh)) != 0) |
466 | goto bad; |
467 | if (eh.e_type != ET_DYN || eh.e_phnum == 0) { |
468 | DPRINTF("bad interpreter type %#x" , eh.e_type); |
469 | error = ENOEXEC; |
470 | goto bad; |
471 | } |
472 | |
473 | phsize = eh.e_phnum * sizeof(Elf_Phdr); |
474 | ph = kmem_alloc(phsize, KM_SLEEP); |
475 | |
476 | if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) |
477 | goto bad; |
478 | |
479 | #ifdef ELF_INTERP_NON_RELOCATABLE |
480 | /* |
481 | * Evil hack: Only MIPS should be non-relocatable, and the |
482 | * psections should have a high address (typically 0x5ffe0000). |
483 | * If it's now relocatable, it should be linked at 0 and the |
484 | * psections should have zeros in the upper part of the address. |
485 | * Otherwise, force the load at the linked address. |
486 | */ |
487 | if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) |
488 | *last = ELFDEFNNAME(NO_ADDR); |
489 | #endif |
490 | |
491 | /* |
492 | * If no position to load the interpreter was set by a probe |
493 | * function, pick the same address that a non-fixed mmap(0, ..) |
494 | * would (i.e. something safely out of the way). |
495 | */ |
496 | if (*last == ELFDEFNNAME(NO_ADDR)) { |
497 | u_long limit = 0; |
498 | /* |
499 | * Find the start and ending addresses of the psections to |
500 | * be loaded. This will give us the size. |
501 | */ |
502 | for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) { |
503 | if (ph[i].p_type == PT_LOAD) { |
504 | u_long psize = ph[i].p_vaddr + ph[i].p_memsz; |
505 | if (base_ph == NULL) |
506 | base_ph = &ph[i]; |
507 | if (psize > limit) |
508 | limit = psize; |
509 | } |
510 | } |
511 | |
512 | if (base_ph == NULL) { |
513 | DPRINTF("no interpreter loadable sections" ); |
514 | error = ENOEXEC; |
515 | goto bad; |
516 | } |
517 | |
518 | /* |
519 | * Now compute the size and load address. |
520 | */ |
521 | addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, |
522 | epp->ep_daddr, |
523 | round_page(limit) - trunc_page(base_ph->p_vaddr), |
524 | use_topdown); |
525 | addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align, |
526 | use_topdown); |
527 | } else { |
528 | addr = *last; /* may be ELF_LINK_ADDR */ |
529 | } |
530 | |
531 | /* |
532 | * Load all the necessary sections |
533 | */ |
534 | for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) { |
535 | switch (ph[i].p_type) { |
536 | case PT_LOAD: { |
537 | u_long size; |
538 | int flags; |
539 | |
540 | if (base_ph == NULL) { |
541 | /* |
542 | * First encountered psection is always the |
543 | * base psection. Make sure it's aligned |
544 | * properly (align down for topdown and align |
545 | * upwards for not topdown). |
546 | */ |
547 | base_ph = &ph[i]; |
548 | flags = VMCMD_BASE; |
549 | if (addr == ELF_LINK_ADDR) |
550 | addr = ph[i].p_vaddr; |
551 | if (use_topdown) |
552 | addr = ELF_TRUNC(addr, ph[i].p_align); |
553 | else |
554 | addr = ELF_ROUND(addr, ph[i].p_align); |
555 | } else { |
556 | u_long limit = round_page(last_ph->p_vaddr |
557 | + last_ph->p_memsz); |
558 | u_long base = trunc_page(ph[i].p_vaddr); |
559 | |
560 | /* |
561 | * If there is a gap in between the psections, |
562 | * map it as inaccessible so nothing else |
563 | * mmap'ed will be placed there. |
564 | */ |
565 | if (limit != base) { |
566 | NEW_VMCMD2(vcset, vmcmd_map_zero, |
567 | base - limit, |
568 | limit - base_ph->p_vaddr, NULLVP, |
569 | 0, VM_PROT_NONE, VMCMD_RELATIVE); |
570 | } |
571 | |
572 | addr = ph[i].p_vaddr - base_ph->p_vaddr; |
573 | flags = VMCMD_RELATIVE; |
574 | } |
575 | last_ph = &ph[i]; |
576 | elf_load_psection(vcset, vp, &ph[i], &addr, |
577 | &size, flags); |
578 | /* |
579 | * If entry is within this psection then this |
580 | * must contain the .text section. *entryoff is |
581 | * relative to the base psection. |
582 | */ |
583 | if (eh.e_entry >= ph[i].p_vaddr && |
584 | eh.e_entry < (ph[i].p_vaddr + size)) { |
585 | *entryoff = eh.e_entry - base_ph->p_vaddr; |
586 | } |
587 | addr += size; |
588 | break; |
589 | } |
590 | |
591 | default: |
592 | break; |
593 | } |
594 | } |
595 | |
596 | kmem_free(ph, phsize); |
597 | /* |
598 | * This value is ignored if TOPDOWN. |
599 | */ |
600 | *last = addr; |
601 | vrele(vp); |
602 | return 0; |
603 | |
604 | badunlock: |
605 | VOP_UNLOCK(vp); |
606 | |
607 | bad: |
608 | if (ph != NULL) |
609 | kmem_free(ph, phsize); |
610 | vrele(vp); |
611 | return error; |
612 | } |
613 | |
614 | /* |
615 | * exec_elf_makecmds(): Prepare an Elf binary's exec package |
616 | * |
617 | * First, set of the various offsets/lengths in the exec package. |
618 | * |
619 | * Then, mark the text image busy (so it can be demand paged) or error |
620 | * out if this is not possible. Finally, set up vmcmds for the |
621 | * text, data, bss, and stack segments. |
622 | */ |
623 | int |
624 | exec_elf_makecmds(struct lwp *l, struct exec_package *epp) |
625 | { |
626 | Elf_Ehdr *eh = epp->ep_hdr; |
627 | Elf_Phdr *ph, *pp; |
628 | Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; |
629 | int error, i; |
630 | char *interp = NULL; |
631 | u_long phsize; |
632 | struct elf_args *ap; |
633 | bool is_dyn = false; |
634 | |
635 | if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) { |
636 | DPRINTF("small header %#x" , epp->ep_hdrvalid); |
637 | return ENOEXEC; |
638 | } |
639 | if ((error = elf_check_header(eh)) != 0) |
640 | return error; |
641 | |
642 | if (eh->e_type == ET_DYN) |
643 | /* PIE, and some libs have an entry point */ |
644 | is_dyn = true; |
645 | else if (eh->e_type != ET_EXEC) { |
646 | DPRINTF("bad type %#x" , eh->e_type); |
647 | return ENOEXEC; |
648 | } |
649 | |
650 | if (eh->e_phnum == 0) { |
651 | DPRINTF("no program headers" ); |
652 | return ENOEXEC; |
653 | } |
654 | |
655 | error = vn_marktext(epp->ep_vp); |
656 | if (error) |
657 | return error; |
658 | |
659 | /* |
660 | * Allocate space to hold all the program headers, and read them |
661 | * from the file |
662 | */ |
663 | phsize = eh->e_phnum * sizeof(Elf_Phdr); |
664 | ph = kmem_alloc(phsize, KM_SLEEP); |
665 | |
666 | if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != |
667 | 0) |
668 | goto bad; |
669 | |
670 | epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); |
671 | epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); |
672 | |
673 | for (i = 0; i < eh->e_phnum; i++) { |
674 | pp = &ph[i]; |
675 | if (pp->p_type == PT_INTERP) { |
676 | if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) { |
677 | DPRINTF("bad interpreter namelen %#jx" , |
678 | (uintmax_t)pp->p_filesz); |
679 | error = ENOEXEC; |
680 | goto bad; |
681 | } |
682 | interp = PNBUF_GET(); |
683 | if ((error = exec_read_from(l, epp->ep_vp, |
684 | pp->p_offset, interp, pp->p_filesz)) != 0) |
685 | goto bad; |
686 | /* Ensure interp is NUL-terminated and of the expected length */ |
687 | if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) { |
688 | DPRINTF("bad interpreter name" ); |
689 | error = ENOEXEC; |
690 | goto bad; |
691 | } |
692 | break; |
693 | } |
694 | } |
695 | |
696 | /* |
697 | * On the same architecture, we may be emulating different systems. |
698 | * See which one will accept this executable. |
699 | * |
700 | * Probe functions would normally see if the interpreter (if any) |
701 | * exists. Emulation packages may possibly replace the interpreter in |
702 | * interp with a changed path (/emul/xxx/<path>). |
703 | */ |
704 | pos = ELFDEFNNAME(NO_ADDR); |
705 | if (epp->ep_esch->u.elf_probe_func) { |
706 | vaddr_t startp = (vaddr_t)pos; |
707 | |
708 | error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, |
709 | &startp); |
710 | if (error) |
711 | goto bad; |
712 | pos = (Elf_Addr)startp; |
713 | } |
714 | |
715 | if (is_dyn) |
716 | elf_placedynexec(epp, eh, ph); |
717 | |
718 | /* |
719 | * Load all the necessary sections |
720 | */ |
721 | for (i = 0; i < eh->e_phnum; i++) { |
722 | Elf_Addr addr = ELFDEFNNAME(NO_ADDR); |
723 | u_long size = 0; |
724 | |
725 | switch (ph[i].p_type) { |
726 | case PT_LOAD: |
727 | elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, |
728 | &ph[i], &addr, &size, VMCMD_FIXED); |
729 | |
730 | /* |
731 | * Consider this as text segment, if it is executable. |
732 | * If there is more than one text segment, pick the |
733 | * largest. |
734 | */ |
735 | if (ph[i].p_flags & PF_X) { |
736 | if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || |
737 | size > epp->ep_tsize) { |
738 | epp->ep_taddr = addr; |
739 | epp->ep_tsize = size; |
740 | } |
741 | end_text = addr + size; |
742 | } else { |
743 | epp->ep_daddr = addr; |
744 | epp->ep_dsize = size; |
745 | } |
746 | if (ph[i].p_offset == 0) { |
747 | computed_phdr = ph[i].p_vaddr + eh->e_phoff; |
748 | } |
749 | break; |
750 | |
751 | case PT_SHLIB: |
752 | /* SCO has these sections. */ |
753 | case PT_INTERP: |
754 | /* Already did this one. */ |
755 | case PT_DYNAMIC: |
756 | case PT_NOTE: |
757 | break; |
758 | case PT_PHDR: |
759 | /* Note address of program headers (in text segment) */ |
760 | phdr = ph[i].p_vaddr; |
761 | break; |
762 | |
763 | default: |
764 | /* |
765 | * Not fatal; we don't need to understand everything. |
766 | */ |
767 | break; |
768 | } |
769 | } |
770 | |
771 | if (epp->ep_vmcmds.evs_used == 0) { |
772 | /* No VMCMD; there was no PT_LOAD section, or those |
773 | * sections were empty */ |
774 | DPRINTF("no vmcommands" ); |
775 | error = ENOEXEC; |
776 | goto bad; |
777 | } |
778 | |
779 | if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { |
780 | epp->ep_daddr = round_page(end_text); |
781 | epp->ep_dsize = 0; |
782 | } |
783 | |
784 | /* |
785 | * Check if we found a dynamically linked binary and arrange to load |
786 | * its interpreter |
787 | */ |
788 | if (interp) { |
789 | u_int nused = epp->ep_vmcmds.evs_used; |
790 | u_long interp_offset = 0; |
791 | |
792 | if ((error = elf_load_interp(l, epp, interp, |
793 | &epp->ep_vmcmds, &interp_offset, &pos)) != 0) { |
794 | goto bad; |
795 | } |
796 | if (epp->ep_vmcmds.evs_used == nused) { |
797 | /* elf_load_interp() has not set up any new VMCMD */ |
798 | DPRINTF("no vmcommands for interpreter" ); |
799 | error = ENOEXEC; |
800 | goto bad; |
801 | } |
802 | |
803 | ap = kmem_alloc(sizeof(*ap), KM_SLEEP); |
804 | ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr; |
805 | epp->ep_entryoffset = interp_offset; |
806 | epp->ep_entry = ap->arg_interp + interp_offset; |
807 | PNBUF_PUT(interp); |
808 | interp = NULL; |
809 | } else { |
810 | epp->ep_entry = eh->e_entry; |
811 | if (epp->ep_flags & EXEC_FORCEAUX) { |
812 | ap = kmem_alloc(sizeof(*ap), KM_SLEEP); |
813 | ap->arg_interp = (vaddr_t)NULL; |
814 | } else |
815 | ap = NULL; |
816 | } |
817 | |
818 | if (ap) { |
819 | ap->arg_phaddr = phdr ? phdr : computed_phdr; |
820 | ap->arg_phentsize = eh->e_phentsize; |
821 | ap->arg_phnum = eh->e_phnum; |
822 | ap->arg_entry = eh->e_entry; |
823 | epp->ep_emul_arg = ap; |
824 | epp->ep_emul_arg_free = elf_free_emul_arg; |
825 | } |
826 | |
827 | #ifdef ELF_MAP_PAGE_ZERO |
828 | /* Dell SVR4 maps page zero, yeuch! */ |
829 | NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, |
830 | epp->ep_vp, 0, VM_PROT_READ); |
831 | #endif |
832 | |
833 | error = (*epp->ep_esch->es_setup_stack)(l, epp); |
834 | if (error) |
835 | goto bad; |
836 | |
837 | kmem_free(ph, phsize); |
838 | return 0; |
839 | |
840 | bad: |
841 | if (interp) |
842 | PNBUF_PUT(interp); |
843 | exec_free_emul_arg(epp); |
844 | kmem_free(ph, phsize); |
845 | kill_vmcmds(&epp->ep_vmcmds); |
846 | return error; |
847 | } |
848 | |
849 | int |
850 | netbsd_elf_signature(struct lwp *l, struct exec_package *epp, |
851 | Elf_Ehdr *eh) |
852 | { |
853 | size_t i; |
854 | Elf_Shdr *sh; |
855 | Elf_Nhdr *np; |
856 | size_t shsize, nsize; |
857 | int error; |
858 | int isnetbsd = 0; |
859 | char *ndata, *ndesc; |
860 | |
861 | #ifdef DIAGNOSTIC |
862 | const char *badnote; |
863 | #define BADNOTE(n) badnote = (n) |
864 | #else |
865 | #define BADNOTE(n) |
866 | #endif |
867 | |
868 | epp->ep_pax_flags = 0; |
869 | if (eh->e_shnum > ELF_MAXSHNUM || eh->e_shnum == 0) { |
870 | DPRINTF("no signature %#x" , eh->e_shnum); |
871 | return ENOEXEC; |
872 | } |
873 | |
874 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
875 | sh = kmem_alloc(shsize, KM_SLEEP); |
876 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
877 | if (error) |
878 | goto out; |
879 | |
880 | np = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP); |
881 | for (i = 0; i < eh->e_shnum; i++) { |
882 | Elf_Shdr *shp = &sh[i]; |
883 | |
884 | if (shp->sh_type != SHT_NOTE || |
885 | shp->sh_size > ELF_MAXNOTESIZE || |
886 | shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) |
887 | continue; |
888 | |
889 | error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, |
890 | shp->sh_size); |
891 | if (error) |
892 | continue; |
893 | |
894 | /* Point to the note, skip the header */ |
895 | ndata = (char *)(np + 1); |
896 | |
897 | /* |
898 | * Padding is present if necessary to ensure 4-byte alignment. |
899 | * The actual section size is therefore: |
900 | * header size + 4-byte aligned name + 4-byte aligned desc |
901 | * Ensure this size is consistent with what is indicated |
902 | * in sh_size. The first check avoids integer overflows. |
903 | * |
904 | * Binaries from before NetBSD 1.6 have two notes in the same |
905 | * note section. The second note was never used, so as long as |
906 | * the section is at least as big as it should be, it's ok. |
907 | * These binaries also have a second note section with a note of |
908 | * type ELF_NOTE_TYPE_NETBSD_TAG, which can be ignored as well. |
909 | */ |
910 | if (np->n_namesz > shp->sh_size || np->n_descsz > shp->sh_size) { |
911 | BADNOTE("note size limit" ); |
912 | goto bad; |
913 | } |
914 | nsize = sizeof(*np) + roundup(np->n_namesz, 4) + |
915 | roundup(np->n_descsz, 4); |
916 | if (nsize > shp->sh_size) { |
917 | BADNOTE("note size" ); |
918 | goto bad; |
919 | } |
920 | ndesc = ndata + roundup(np->n_namesz, 4); |
921 | |
922 | switch (np->n_type) { |
923 | case ELF_NOTE_TYPE_NETBSD_TAG: |
924 | /* It is us */ |
925 | if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ && |
926 | np->n_descsz == ELF_NOTE_NETBSD_DESCSZ && |
927 | memcmp(ndata, ELF_NOTE_NETBSD_NAME, |
928 | ELF_NOTE_NETBSD_NAMESZ) == 0) { |
929 | memcpy(&epp->ep_osversion, ndesc, |
930 | ELF_NOTE_NETBSD_DESCSZ); |
931 | isnetbsd = 1; |
932 | break; |
933 | } |
934 | |
935 | /* |
936 | * Ignore SuSE tags; SuSE's n_type is the same the |
937 | * NetBSD one. |
938 | */ |
939 | if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ && |
940 | memcmp(ndata, ELF_NOTE_SUSE_NAME, |
941 | ELF_NOTE_SUSE_NAMESZ) == 0) |
942 | break; |
943 | /* |
944 | * Ignore old GCC |
945 | */ |
946 | if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ && |
947 | memcmp(ndata, ELF_NOTE_OGCC_NAME, |
948 | ELF_NOTE_OGCC_NAMESZ) == 0) |
949 | break; |
950 | BADNOTE("NetBSD tag" ); |
951 | goto bad; |
952 | |
953 | case ELF_NOTE_TYPE_PAX_TAG: |
954 | if (np->n_namesz == ELF_NOTE_PAX_NAMESZ && |
955 | np->n_descsz == ELF_NOTE_PAX_DESCSZ && |
956 | memcmp(ndata, ELF_NOTE_PAX_NAME, |
957 | ELF_NOTE_PAX_NAMESZ) == 0) { |
958 | uint32_t flags; |
959 | memcpy(&flags, ndesc, sizeof(flags)); |
960 | /* Convert the flags and insert them into |
961 | * the exec package. */ |
962 | pax_setup_elf_flags(epp, flags); |
963 | break; |
964 | } |
965 | BADNOTE("PaX tag" ); |
966 | goto bad; |
967 | |
968 | case ELF_NOTE_TYPE_MARCH_TAG: |
969 | /* Copy the machine arch into the package. */ |
970 | if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ |
971 | && memcmp(ndata, ELF_NOTE_MARCH_NAME, |
972 | ELF_NOTE_MARCH_NAMESZ) == 0) { |
973 | /* Do not truncate the buffer */ |
974 | if (np->n_descsz > sizeof(epp->ep_machine_arch)) { |
975 | BADNOTE("description size limit" ); |
976 | goto bad; |
977 | } |
978 | /* |
979 | * Ensure ndesc is NUL-terminated and of the |
980 | * expected length. |
981 | */ |
982 | if (strnlen(ndesc, np->n_descsz) + 1 != |
983 | np->n_descsz) { |
984 | BADNOTE("description size" ); |
985 | goto bad; |
986 | } |
987 | strlcpy(epp->ep_machine_arch, ndesc, |
988 | sizeof(epp->ep_machine_arch)); |
989 | break; |
990 | } |
991 | BADNOTE("march tag" ); |
992 | goto bad; |
993 | |
994 | case ELF_NOTE_TYPE_MCMODEL_TAG: |
995 | /* arch specific check for code model */ |
996 | #ifdef ELF_MD_MCMODEL_CHECK |
997 | if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ |
998 | && memcmp(ndata, ELF_NOTE_MCMODEL_NAME, |
999 | ELF_NOTE_MCMODEL_NAMESZ) == 0) { |
1000 | ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz); |
1001 | break; |
1002 | } |
1003 | BADNOTE("mcmodel tag" ); |
1004 | goto bad; |
1005 | #endif |
1006 | break; |
1007 | |
1008 | case ELF_NOTE_TYPE_SUSE_VERSION_TAG: |
1009 | break; |
1010 | |
1011 | case ELF_NOTE_TYPE_GO_BUILDID_TAG: |
1012 | break; |
1013 | |
1014 | default: |
1015 | BADNOTE("unknown tag" ); |
1016 | bad: |
1017 | #ifdef DIAGNOSTIC |
1018 | /* Ignore GNU tags */ |
1019 | if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && |
1020 | memcmp(ndata, ELF_NOTE_GNU_NAME, |
1021 | ELF_NOTE_GNU_NAMESZ) == 0) |
1022 | break; |
1023 | |
1024 | int ns = MIN(np->n_namesz, shp->sh_size - sizeof(*np)); |
1025 | printf("%s: Unknown elf note type %d (%s): " |
1026 | "[namesz=%d, descsz=%d name=%-*.*s]\n" , |
1027 | epp->ep_kname, np->n_type, badnote, np->n_namesz, |
1028 | np->n_descsz, ns, ns, ndata); |
1029 | #endif |
1030 | break; |
1031 | } |
1032 | } |
1033 | kmem_free(np, ELF_MAXNOTESIZE); |
1034 | |
1035 | error = isnetbsd ? 0 : ENOEXEC; |
1036 | #ifdef DEBUG_ELF |
1037 | if (error) |
1038 | DPRINTF("not netbsd" ); |
1039 | #endif |
1040 | out: |
1041 | kmem_free(sh, shsize); |
1042 | return error; |
1043 | } |
1044 | |
1045 | int |
1046 | netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, |
1047 | vaddr_t *pos) |
1048 | { |
1049 | int error; |
1050 | |
1051 | if ((error = netbsd_elf_signature(l, epp, eh)) != 0) |
1052 | return error; |
1053 | #ifdef ELF_MD_PROBE_FUNC |
1054 | if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) |
1055 | return error; |
1056 | #elif defined(ELF_INTERP_NON_RELOCATABLE) |
1057 | *pos = ELF_LINK_ADDR; |
1058 | #endif |
1059 | epp->ep_flags |= EXEC_FORCEAUX; |
1060 | return 0; |
1061 | } |
1062 | |
1063 | void |
1064 | elf_free_emul_arg(void *arg) |
1065 | { |
1066 | struct elf_args *ap = arg; |
1067 | KASSERT(ap != NULL); |
1068 | kmem_free(ap, sizeof(*ap)); |
1069 | } |
1070 | |