1/* $NetBSD: exec_elf.c,v 1.98 2019/06/07 23:35:52 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 1.98 2019/06/07 23:35:52 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
88extern struct emul emul_netbsd;
89
90#define elf_check_header ELFNAME(check_header)
91#define elf_copyargs ELFNAME(copyargs)
92#define elf_populate_auxv ELFNAME(populate_auxv)
93#define elf_load_interp ELFNAME(load_interp)
94#define elf_load_psection ELFNAME(load_psection)
95#define exec_elf_makecmds ELFNAME2(exec,makecmds)
96#define netbsd_elf_signature ELFNAME2(netbsd,signature)
97#define netbsd_elf_note ELFNAME2(netbsd,note)
98#define netbsd_elf_probe ELFNAME2(netbsd,probe)
99#define coredump ELFNAMEEND(coredump)
100#define elf_free_emul_arg ELFNAME(free_emul_arg)
101
102static int
103elf_load_interp(struct lwp *, struct exec_package *, char *,
104 struct exec_vmcmd_set *, u_long *, Elf_Addr *);
105static int
106elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *,
107 Elf_Addr *, u_long *, int);
108
109int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *);
110int netbsd_elf_note(struct exec_package *, const Elf_Nhdr *, const char *,
111 const char *);
112int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *,
113 vaddr_t *);
114
115static void elf_free_emul_arg(void *);
116
117#ifdef DEBUG_ELF
118#define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__)
119#else
120#define DPRINTF(a, ...)
121#endif
122
123/* round up and down to page boundaries. */
124#define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1))
125#define ELF_TRUNC(a, b) ((a) & ~((b) - 1))
126
127static int
128elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph)
129{
130 Elf_Addr align, offset;
131 int i;
132
133 for (align = 1, i = 0; i < eh->e_phnum; i++)
134 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align)
135 align = ph[i].p_align;
136
137 offset = (Elf_Addr)pax_aslr_exec_offset(epp, align);
138 if (offset < epp->ep_vm_minaddr)
139 offset = roundup(epp->ep_vm_minaddr, align);
140 if ((offset & (align - 1)) != 0) {
141 DPRINTF("bad offset=%#jx align=%#jx",
142 (uintmax_t)offset, (uintmax_t)align);
143 return EINVAL;
144 }
145
146 for (i = 0; i < eh->e_phnum; i++)
147 ph[i].p_vaddr += offset;
148 epp->ep_entryoffset = offset;
149 eh->e_entry += offset;
150 return 0;
151}
152
153
154int
155elf_populate_auxv(struct lwp *l, struct exec_package *pack, char **stackp)
156{
157 size_t len, vlen;
158 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname;
159 struct elf_args *ap;
160 int error;
161
162 a = ai;
163
164 memset(ai, 0, sizeof(ai));
165
166 /*
167 * Push extra arguments on the stack needed by dynamically
168 * linked binaries
169 */
170 if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
171 struct vattr *vap = pack->ep_vap;
172
173 a->a_type = AT_PHDR;
174 a->a_v = ap->arg_phaddr;
175 a++;
176
177 a->a_type = AT_PHENT;
178 a->a_v = ap->arg_phentsize;
179 a++;
180
181 a->a_type = AT_PHNUM;
182 a->a_v = ap->arg_phnum;
183 a++;
184
185 a->a_type = AT_PAGESZ;
186 a->a_v = PAGE_SIZE;
187 a++;
188
189 a->a_type = AT_BASE;
190 a->a_v = ap->arg_interp;
191 a++;
192
193 a->a_type = AT_FLAGS;
194 a->a_v = 0;
195 a++;
196
197 a->a_type = AT_ENTRY;
198 a->a_v = ap->arg_entry;
199 a++;
200
201 a->a_type = AT_EUID;
202 if (vap->va_mode & S_ISUID)
203 a->a_v = vap->va_uid;
204 else
205 a->a_v = kauth_cred_geteuid(l->l_cred);
206 a++;
207
208 a->a_type = AT_RUID;
209 a->a_v = kauth_cred_getuid(l->l_cred);
210 a++;
211
212 a->a_type = AT_EGID;
213 if (vap->va_mode & S_ISGID)
214 a->a_v = vap->va_gid;
215 else
216 a->a_v = kauth_cred_getegid(l->l_cred);
217 a++;
218
219 a->a_type = AT_RGID;
220 a->a_v = kauth_cred_getgid(l->l_cred);
221 a++;
222
223 a->a_type = AT_STACKBASE;
224 a->a_v = l->l_proc->p_stackbase;
225 a++;
226
227 execname = a;
228 a->a_type = AT_SUN_EXECNAME;
229 a++;
230
231 exec_free_emul_arg(pack);
232 } else {
233 execname = NULL;
234 }
235
236 a->a_type = AT_NULL;
237 a->a_v = 0;
238 a++;
239
240 vlen = (a - ai) * sizeof(ai[0]);
241
242 KASSERT(vlen <= sizeof(ai));
243
244 if (execname) {
245 char *path = l->l_proc->p_path;
246 execname->a_v = (uintptr_t)(*stackp + vlen);
247 len = strlen(path) + 1;
248 if ((error = copyout(path, (*stackp + vlen), len)) != 0)
249 return error;
250 len = ALIGN(len);
251 } else {
252 len = 0;
253 }
254
255 if ((error = copyout(ai, *stackp, vlen)) != 0)
256 return error;
257 *stackp += vlen + len;
258
259 return 0;
260}
261
262/*
263 * Copy arguments onto the stack in the normal way, but add some
264 * extra information in case of dynamic binding.
265 */
266int
267elf_copyargs(struct lwp *l, struct exec_package *pack,
268 struct ps_strings *arginfo, char **stackp, void *argp)
269{
270 int error;
271
272 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0)
273 return error;
274
275 return elf_populate_auxv(l, pack, stackp);
276}
277
278/*
279 * elf_check_header():
280 *
281 * Check header for validity; return 0 if ok, ENOEXEC if error
282 */
283int
284elf_check_header(Elf_Ehdr *eh)
285{
286
287 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
288 eh->e_ident[EI_CLASS] != ELFCLASS) {
289 DPRINTF("bad magic e_ident[EI_MAG0,EI_MAG3] %#x%x%x%x, "
290 "e_ident[EI_CLASS] %#x", eh->e_ident[EI_MAG0],
291 eh->e_ident[EI_MAG1], eh->e_ident[EI_MAG2],
292 eh->e_ident[EI_MAG3], eh->e_ident[EI_CLASS]);
293 return ENOEXEC;
294 }
295
296 switch (eh->e_machine) {
297
298 ELFDEFNNAME(MACHDEP_ID_CASES)
299
300 default:
301 DPRINTF("bad machine %#x", eh->e_machine);
302 return ENOEXEC;
303 }
304
305 if (ELF_EHDR_FLAGS_OK(eh) == 0) {
306 DPRINTF("bad flags %#x", eh->e_flags);
307 return ENOEXEC;
308 }
309
310 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) {
311 DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum);
312 return ENOEXEC;
313 }
314
315 return 0;
316}
317
318/*
319 * elf_load_psection():
320 *
321 * Load a psection at the appropriate address
322 */
323static int
324elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp,
325 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags)
326{
327 u_long msize, psize, rm, rf;
328 long diff, offset;
329 int vmprot = 0;
330
331 /*
332 * If the user specified an address, then we load there.
333 */
334 if (*addr == ELFDEFNNAME(NO_ADDR))
335 *addr = ph->p_vaddr;
336
337 if (ph->p_align > 1) {
338 /*
339 * Make sure we are virtually aligned as we are supposed to be.
340 */
341 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align);
342 if (*addr - diff != ELF_TRUNC(*addr, ph->p_align)) {
343 DPRINTF("bad alignment %#jx != %#jx\n",
344 (uintptr_t)(*addr - diff),
345 (uintptr_t)ELF_TRUNC(*addr, ph->p_align));
346 return EINVAL;
347 }
348 /*
349 * But make sure to not map any pages before the start of the
350 * psection by limiting the difference to within a page.
351 */
352 diff &= PAGE_MASK;
353 } else
354 diff = 0;
355
356 vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
357 vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
358 vmprot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
359
360 /*
361 * Adjust everything so it all starts on a page boundary.
362 */
363 *addr -= diff;
364 offset = ph->p_offset - diff;
365 *size = ph->p_filesz + diff;
366 msize = ph->p_memsz + diff;
367
368 if (ph->p_align >= PAGE_SIZE) {
369 if ((ph->p_flags & PF_W) != 0) {
370 /*
371 * Because the pagedvn pager can't handle zero fill
372 * of the last data page if it's not page aligned we
373 * map the last page readvn.
374 */
375 psize = trunc_page(*size);
376 } else {
377 psize = round_page(*size);
378 }
379 } else {
380 psize = *size;
381 }
382
383 if (psize > 0) {
384 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ?
385 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp,
386 offset, vmprot, flags);
387 flags &= VMCMD_RELATIVE;
388 }
389 if (psize < *size) {
390 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
391 *addr + psize, vp, offset + psize, vmprot, flags);
392 }
393
394 /*
395 * Check if we need to extend the size of the segment (does
396 * bss extend page the next page boundary)?
397 */
398 rm = round_page(*addr + msize);
399 rf = round_page(*addr + *size);
400
401 if (rm != rf) {
402 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
403 0, vmprot, flags & VMCMD_RELATIVE);
404 *size = msize;
405 }
406 return 0;
407}
408
409/*
410 * elf_load_interp():
411 *
412 * Load an interpreter pointed to by path.
413 */
414static int
415elf_load_interp(struct lwp *l, struct exec_package *epp, char *path,
416 struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last)
417{
418 int error, i;
419 struct vnode *vp;
420 struct vattr attr;
421 Elf_Ehdr eh;
422 Elf_Phdr *ph = NULL;
423 const Elf_Phdr *base_ph;
424 const Elf_Phdr *last_ph;
425 u_long phsize;
426 Elf_Addr addr = *last;
427 struct proc *p;
428 bool use_topdown;
429
430 p = l->l_proc;
431
432 KASSERT(p->p_vmspace);
433 KASSERT(p->p_vmspace != proc0.p_vmspace);
434
435#ifdef __USE_TOPDOWN_VM
436 use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM;
437#else
438 use_topdown = false;
439#endif
440
441 /*
442 * 1. open file
443 * 2. read filehdr
444 * 3. map text, data, and bss out of it using VM_*
445 */
446 vp = epp->ep_interp;
447 if (vp == NULL) {
448 error = emul_find_interp(l, epp, path);
449 if (error != 0)
450 return error;
451 vp = epp->ep_interp;
452 }
453 /* We'll tidy this ourselves - otherwise we have locking issues */
454 epp->ep_interp = NULL;
455 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
456
457 /*
458 * Similarly, if it's not marked as executable, or it's not a regular
459 * file, we don't allow it to be used.
460 */
461 if (vp->v_type != VREG) {
462 error = EACCES;
463 goto badunlock;
464 }
465 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0)
466 goto badunlock;
467
468 /* get attributes */
469 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0)
470 goto badunlock;
471
472 /*
473 * Check mount point. Though we're not trying to exec this binary,
474 * we will be executing code from it, so if the mount point
475 * disallows execution or set-id-ness, we punt or kill the set-id.
476 */
477 if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
478 error = EACCES;
479 goto badunlock;
480 }
481 if (vp->v_mount->mnt_flag & MNT_NOSUID)
482 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
483
484 error = vn_marktext(vp);
485 if (error)
486 goto badunlock;
487
488 VOP_UNLOCK(vp);
489
490 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0)
491 goto bad;
492
493 if ((error = elf_check_header(&eh)) != 0)
494 goto bad;
495 if (eh.e_type != ET_DYN || eh.e_phnum == 0) {
496 DPRINTF("bad interpreter type %#x", eh.e_type);
497 error = ENOEXEC;
498 goto bad;
499 }
500
501 phsize = eh.e_phnum * sizeof(Elf_Phdr);
502 ph = kmem_alloc(phsize, KM_SLEEP);
503
504 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0)
505 goto bad;
506
507#ifdef ELF_INTERP_NON_RELOCATABLE
508 /*
509 * Evil hack: Only MIPS should be non-relocatable, and the
510 * psections should have a high address (typically 0x5ffe0000).
511 * If it's now relocatable, it should be linked at 0 and the
512 * psections should have zeros in the upper part of the address.
513 * Otherwise, force the load at the linked address.
514 */
515 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0)
516 *last = ELFDEFNNAME(NO_ADDR);
517#endif
518
519 /*
520 * If no position to load the interpreter was set by a probe
521 * function, pick the same address that a non-fixed mmap(0, ..)
522 * would (i.e. something safely out of the way).
523 */
524 if (*last == ELFDEFNNAME(NO_ADDR)) {
525 u_long limit = 0;
526 /*
527 * Find the start and ending addresses of the psections to
528 * be loaded. This will give us the size.
529 */
530 for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) {
531 if (ph[i].p_type == PT_LOAD) {
532 u_long psize = ph[i].p_vaddr + ph[i].p_memsz;
533 if (base_ph == NULL)
534 base_ph = &ph[i];
535 if (psize > limit)
536 limit = psize;
537 }
538 }
539
540 if (base_ph == NULL) {
541 DPRINTF("no interpreter loadable sections");
542 error = ENOEXEC;
543 goto bad;
544 }
545
546 /*
547 * Now compute the size and load address.
548 */
549 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p,
550 epp->ep_daddr,
551 round_page(limit) - trunc_page(base_ph->p_vaddr),
552 use_topdown);
553 addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align,
554 use_topdown);
555 } else {
556 addr = *last; /* may be ELF_LINK_ADDR */
557 }
558
559 /*
560 * Load all the necessary sections
561 */
562 for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) {
563 switch (ph[i].p_type) {
564 case PT_LOAD: {
565 u_long size;
566 int flags;
567
568 if (base_ph == NULL) {
569 /*
570 * First encountered psection is always the
571 * base psection. Make sure it's aligned
572 * properly (align down for topdown and align
573 * upwards for not topdown).
574 */
575 base_ph = &ph[i];
576 flags = VMCMD_BASE;
577 if (addr == ELF_LINK_ADDR)
578 addr = ph[i].p_vaddr;
579 if (use_topdown)
580 addr = ELF_TRUNC(addr, ph[i].p_align);
581 else
582 addr = ELF_ROUND(addr, ph[i].p_align);
583 } else {
584 u_long limit = round_page(last_ph->p_vaddr
585 + last_ph->p_memsz);
586 u_long base = trunc_page(ph[i].p_vaddr);
587
588 /*
589 * If there is a gap in between the psections,
590 * map it as inaccessible so nothing else
591 * mmap'ed will be placed there.
592 */
593 if (limit != base) {
594 NEW_VMCMD2(vcset, vmcmd_map_zero,
595 base - limit,
596 limit - base_ph->p_vaddr, NULLVP,
597 0, VM_PROT_NONE, VMCMD_RELATIVE);
598 }
599
600 addr = ph[i].p_vaddr - base_ph->p_vaddr;
601 flags = VMCMD_RELATIVE;
602 }
603 last_ph = &ph[i];
604 if ((error = elf_load_psection(vcset, vp, &ph[i], &addr,
605 &size, flags)) != 0)
606 goto bad;
607 /*
608 * If entry is within this psection then this
609 * must contain the .text section. *entryoff is
610 * relative to the base psection.
611 */
612 if (eh.e_entry >= ph[i].p_vaddr &&
613 eh.e_entry < (ph[i].p_vaddr + size)) {
614 *entryoff = eh.e_entry - base_ph->p_vaddr;
615 }
616 addr += size;
617 break;
618 }
619
620 default:
621 break;
622 }
623 }
624
625 kmem_free(ph, phsize);
626 /*
627 * This value is ignored if TOPDOWN.
628 */
629 *last = addr;
630 vrele(vp);
631 return 0;
632
633badunlock:
634 VOP_UNLOCK(vp);
635
636bad:
637 if (ph != NULL)
638 kmem_free(ph, phsize);
639 vrele(vp);
640 return error;
641}
642
643/*
644 * exec_elf_makecmds(): Prepare an Elf binary's exec package
645 *
646 * First, set of the various offsets/lengths in the exec package.
647 *
648 * Then, mark the text image busy (so it can be demand paged) or error
649 * out if this is not possible. Finally, set up vmcmds for the
650 * text, data, bss, and stack segments.
651 */
652int
653exec_elf_makecmds(struct lwp *l, struct exec_package *epp)
654{
655 Elf_Ehdr *eh = epp->ep_hdr;
656 Elf_Phdr *ph, *pp;
657 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0;
658 int error, i;
659 char *interp = NULL;
660 u_long phsize;
661 struct elf_args *ap;
662 bool is_dyn = false;
663
664 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) {
665 DPRINTF("small header %#x", epp->ep_hdrvalid);
666 return ENOEXEC;
667 }
668 if ((error = elf_check_header(eh)) != 0)
669 return error;
670
671 if (eh->e_type == ET_DYN)
672 /* PIE, and some libs have an entry point */
673 is_dyn = true;
674 else if (eh->e_type != ET_EXEC) {
675 DPRINTF("bad type %#x", eh->e_type);
676 return ENOEXEC;
677 }
678
679 if (eh->e_phnum == 0) {
680 DPRINTF("no program headers");
681 return ENOEXEC;
682 }
683
684 error = vn_marktext(epp->ep_vp);
685 if (error)
686 return error;
687
688 /*
689 * Allocate space to hold all the program headers, and read them
690 * from the file
691 */
692 phsize = eh->e_phnum * sizeof(Elf_Phdr);
693 ph = kmem_alloc(phsize, KM_SLEEP);
694
695 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) !=
696 0)
697 goto bad;
698
699 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
700 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
701
702 for (i = 0; i < eh->e_phnum; i++) {
703 pp = &ph[i];
704 if (pp->p_type == PT_INTERP) {
705 if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) {
706 DPRINTF("bad interpreter namelen %#jx",
707 (uintmax_t)pp->p_filesz);
708 error = ENOEXEC;
709 goto bad;
710 }
711 interp = PNBUF_GET();
712 if ((error = exec_read_from(l, epp->ep_vp,
713 pp->p_offset, interp, pp->p_filesz)) != 0)
714 goto bad;
715 /* Ensure interp is NUL-terminated and of the expected length */
716 if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) {
717 DPRINTF("bad interpreter name");
718 error = ENOEXEC;
719 goto bad;
720 }
721 break;
722 }
723 }
724
725 /*
726 * On the same architecture, we may be emulating different systems.
727 * See which one will accept this executable.
728 *
729 * Probe functions would normally see if the interpreter (if any)
730 * exists. Emulation packages may possibly replace the interpreter in
731 * interp with a changed path (/emul/xxx/<path>).
732 */
733 pos = ELFDEFNNAME(NO_ADDR);
734 if (epp->ep_esch->u.elf_probe_func) {
735 vaddr_t startp = (vaddr_t)pos;
736
737 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp,
738 &startp);
739 if (error)
740 goto bad;
741 pos = (Elf_Addr)startp;
742 }
743
744 if (is_dyn && (error = elf_placedynexec(epp, eh, ph)) != 0)
745 goto bad;
746
747 /*
748 * Load all the necessary sections
749 */
750 for (i = 0; i < eh->e_phnum; i++) {
751 Elf_Addr addr = ELFDEFNNAME(NO_ADDR);
752 u_long size = 0;
753
754 switch (ph[i].p_type) {
755 case PT_LOAD:
756 if ((error = elf_load_psection(&epp->ep_vmcmds,
757 epp->ep_vp, &ph[i], &addr, &size, VMCMD_FIXED))
758 != 0)
759 goto bad;
760
761 /*
762 * Consider this as text segment, if it is executable.
763 * If there is more than one text segment, pick the
764 * largest.
765 */
766 if (ph[i].p_flags & PF_X) {
767 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) ||
768 size > epp->ep_tsize) {
769 epp->ep_taddr = addr;
770 epp->ep_tsize = size;
771 }
772 end_text = addr + size;
773 } else {
774 epp->ep_daddr = addr;
775 epp->ep_dsize = size;
776 }
777 if (ph[i].p_offset == 0) {
778 computed_phdr = ph[i].p_vaddr + eh->e_phoff;
779 }
780 break;
781
782 case PT_SHLIB:
783 /* SCO has these sections. */
784 case PT_INTERP:
785 /* Already did this one. */
786 case PT_DYNAMIC:
787 case PT_NOTE:
788 break;
789 case PT_PHDR:
790 /* Note address of program headers (in text segment) */
791 phdr = ph[i].p_vaddr;
792 break;
793
794 default:
795 /*
796 * Not fatal; we don't need to understand everything.
797 */
798 break;
799 }
800 }
801
802 if (epp->ep_vmcmds.evs_used == 0) {
803 /* No VMCMD; there was no PT_LOAD section, or those
804 * sections were empty */
805 DPRINTF("no vmcommands");
806 error = ENOEXEC;
807 goto bad;
808 }
809
810 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
811 epp->ep_daddr = round_page(end_text);
812 epp->ep_dsize = 0;
813 }
814
815 /*
816 * Check if we found a dynamically linked binary and arrange to load
817 * its interpreter
818 */
819 if (interp) {
820 u_int nused = epp->ep_vmcmds.evs_used;
821 u_long interp_offset = 0;
822
823 if ((error = elf_load_interp(l, epp, interp,
824 &epp->ep_vmcmds, &interp_offset, &pos)) != 0) {
825 goto bad;
826 }
827 if (epp->ep_vmcmds.evs_used == nused) {
828 /* elf_load_interp() has not set up any new VMCMD */
829 DPRINTF("no vmcommands for interpreter");
830 error = ENOEXEC;
831 goto bad;
832 }
833
834 ap = kmem_alloc(sizeof(*ap), KM_SLEEP);
835 ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr;
836 epp->ep_entryoffset = interp_offset;
837 epp->ep_entry = ap->arg_interp + interp_offset;
838 PNBUF_PUT(interp);
839 interp = NULL;
840 } else {
841 epp->ep_entry = eh->e_entry;
842 if (epp->ep_flags & EXEC_FORCEAUX) {
843 ap = kmem_zalloc(sizeof(*ap), KM_SLEEP);
844 ap->arg_interp = (vaddr_t)NULL;
845 } else {
846 ap = NULL;
847 }
848 }
849
850 if (ap) {
851 ap->arg_phaddr = phdr ? phdr : computed_phdr;
852 ap->arg_phentsize = eh->e_phentsize;
853 ap->arg_phnum = eh->e_phnum;
854 ap->arg_entry = eh->e_entry;
855 epp->ep_emul_arg = ap;
856 epp->ep_emul_arg_free = elf_free_emul_arg;
857 }
858
859#ifdef ELF_MAP_PAGE_ZERO
860 /* Dell SVR4 maps page zero, yeuch! */
861 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0,
862 epp->ep_vp, 0, VM_PROT_READ);
863#endif
864
865 error = (*epp->ep_esch->es_setup_stack)(l, epp);
866 if (error)
867 goto bad;
868
869 kmem_free(ph, phsize);
870 return 0;
871
872bad:
873 if (interp)
874 PNBUF_PUT(interp);
875 exec_free_emul_arg(epp);
876 kmem_free(ph, phsize);
877 kill_vmcmds(&epp->ep_vmcmds);
878 return error;
879}
880
881int
882netbsd_elf_signature(struct lwp *l, struct exec_package *epp,
883 Elf_Ehdr *eh)
884{
885 size_t i;
886 Elf_Phdr *ph;
887 size_t phsize;
888 char *nbuf;
889 int error;
890 int isnetbsd = 0;
891
892 epp->ep_pax_flags = 0;
893
894 if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) {
895 DPRINTF("no signature %#x", eh->e_phnum);
896 return ENOEXEC;
897 }
898
899 phsize = eh->e_phnum * sizeof(Elf_Phdr);
900 ph = kmem_alloc(phsize, KM_SLEEP);
901 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize);
902 if (error)
903 goto out;
904
905 nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP);
906 for (i = 0; i < eh->e_phnum; i++) {
907 const char *nptr;
908 size_t nlen;
909
910 if (ph[i].p_type != PT_NOTE ||
911 ph[i].p_filesz > ELF_MAXNOTESIZE)
912 continue;
913
914 nlen = ph[i].p_filesz;
915 error = exec_read_from(l, epp->ep_vp, ph[i].p_offset,
916 nbuf, nlen);
917 if (error)
918 continue;
919
920 nptr = nbuf;
921 while (nlen > 0) {
922 const Elf_Nhdr *np;
923 const char *ndata, *ndesc;
924
925 /* note header */
926 np = (const Elf_Nhdr *)nptr;
927 if (nlen < sizeof(*np)) {
928 break;
929 }
930 nptr += sizeof(*np);
931 nlen -= sizeof(*np);
932
933 /* note name */
934 ndata = nptr;
935 if (nlen < roundup(np->n_namesz, 4)) {
936 break;
937 }
938 nptr += roundup(np->n_namesz, 4);
939 nlen -= roundup(np->n_namesz, 4);
940
941 /* note description */
942 ndesc = nptr;
943 if (nlen < roundup(np->n_descsz, 4)) {
944 break;
945 }
946 nptr += roundup(np->n_descsz, 4);
947 nlen -= roundup(np->n_descsz, 4);
948
949 isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc);
950 }
951 }
952 kmem_free(nbuf, ELF_MAXNOTESIZE);
953
954 error = isnetbsd ? 0 : ENOEXEC;
955#ifdef DEBUG_ELF
956 if (error)
957 DPRINTF("not netbsd");
958#endif
959out:
960 kmem_free(ph, phsize);
961 return error;
962}
963
964int
965netbsd_elf_note(struct exec_package *epp,
966 const Elf_Nhdr *np, const char *ndata, const char *ndesc)
967{
968 int isnetbsd = 0;
969
970#ifdef DIAGNOSTIC
971 const char *badnote;
972#define BADNOTE(n) badnote = (n)
973#else
974#define BADNOTE(n)
975#endif
976
977 switch (np->n_type) {
978 case ELF_NOTE_TYPE_NETBSD_TAG:
979 /* It is us */
980 if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ &&
981 np->n_descsz == ELF_NOTE_NETBSD_DESCSZ &&
982 memcmp(ndata, ELF_NOTE_NETBSD_NAME,
983 ELF_NOTE_NETBSD_NAMESZ) == 0) {
984 memcpy(&epp->ep_osversion, ndesc,
985 ELF_NOTE_NETBSD_DESCSZ);
986 isnetbsd = 1;
987 break;
988 }
989
990 /*
991 * Ignore SuSE tags; SuSE's n_type is the same the
992 * NetBSD one.
993 */
994 if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ &&
995 memcmp(ndata, ELF_NOTE_SUSE_NAME,
996 ELF_NOTE_SUSE_NAMESZ) == 0)
997 break;
998 /*
999 * Ignore old GCC
1000 */
1001 if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ &&
1002 memcmp(ndata, ELF_NOTE_OGCC_NAME,
1003 ELF_NOTE_OGCC_NAMESZ) == 0)
1004 break;
1005 BADNOTE("NetBSD tag");
1006 goto bad;
1007
1008 case ELF_NOTE_TYPE_PAX_TAG:
1009 if (np->n_namesz == ELF_NOTE_PAX_NAMESZ &&
1010 np->n_descsz == ELF_NOTE_PAX_DESCSZ &&
1011 memcmp(ndata, ELF_NOTE_PAX_NAME,
1012 ELF_NOTE_PAX_NAMESZ) == 0) {
1013 uint32_t flags;
1014 memcpy(&flags, ndesc, sizeof(flags));
1015 /* Convert the flags and insert them into
1016 * the exec package. */
1017 pax_setup_elf_flags(epp, flags);
1018 break;
1019 }
1020 BADNOTE("PaX tag");
1021 goto bad;
1022
1023 case ELF_NOTE_TYPE_MARCH_TAG:
1024 /* Copy the machine arch into the package. */
1025 if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ
1026 && memcmp(ndata, ELF_NOTE_MARCH_NAME,
1027 ELF_NOTE_MARCH_NAMESZ) == 0) {
1028 /* Do not truncate the buffer */
1029 if (np->n_descsz > sizeof(epp->ep_machine_arch)) {
1030 BADNOTE("description size limit");
1031 goto bad;
1032 }
1033 /*
1034 * Ensure ndesc is NUL-terminated and of the
1035 * expected length.
1036 */
1037 if (strnlen(ndesc, np->n_descsz) + 1 !=
1038 np->n_descsz) {
1039 BADNOTE("description size");
1040 goto bad;
1041 }
1042 strlcpy(epp->ep_machine_arch, ndesc,
1043 sizeof(epp->ep_machine_arch));
1044 break;
1045 }
1046 BADNOTE("march tag");
1047 goto bad;
1048
1049 case ELF_NOTE_TYPE_MCMODEL_TAG:
1050 /* arch specific check for code model */
1051#ifdef ELF_MD_MCMODEL_CHECK
1052 if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ
1053 && memcmp(ndata, ELF_NOTE_MCMODEL_NAME,
1054 ELF_NOTE_MCMODEL_NAMESZ) == 0) {
1055 ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz);
1056 break;
1057 }
1058 BADNOTE("mcmodel tag");
1059 goto bad;
1060#endif
1061 break;
1062
1063 case ELF_NOTE_TYPE_SUSE_VERSION_TAG:
1064 break;
1065
1066 case ELF_NOTE_TYPE_GO_BUILDID_TAG:
1067 break;
1068
1069 case ELF_NOTE_TYPE_NETBSD_EMUL_TAG:
1070 /* Ancient NetBSD version tag */
1071 break;
1072
1073 default:
1074 BADNOTE("unknown tag");
1075bad:
1076#ifdef DIAGNOSTIC
1077 /* Ignore GNU tags */
1078 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ &&
1079 memcmp(ndata, ELF_NOTE_GNU_NAME,
1080 ELF_NOTE_GNU_NAMESZ) == 0)
1081 break;
1082
1083 int ns = (int)np->n_namesz;
1084 printf("%s: Unknown elf note type %d (%s): "
1085 "[namesz=%d, descsz=%d name=%-*.*s]\n",
1086 epp->ep_kname, np->n_type, badnote, np->n_namesz,
1087 np->n_descsz, ns, ns, ndata);
1088#endif
1089 break;
1090 }
1091
1092 return isnetbsd;
1093}
1094
1095int
1096netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp,
1097 vaddr_t *pos)
1098{
1099 int error;
1100
1101 if ((error = netbsd_elf_signature(l, epp, eh)) != 0)
1102 return error;
1103#ifdef ELF_MD_PROBE_FUNC
1104 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0)
1105 return error;
1106#elif defined(ELF_INTERP_NON_RELOCATABLE)
1107 *pos = ELF_LINK_ADDR;
1108#endif
1109 epp->ep_flags |= EXEC_FORCEAUX;
1110 return 0;
1111}
1112
1113void
1114elf_free_emul_arg(void *arg)
1115{
1116 struct elf_args *ap = arg;
1117 KASSERT(ap != NULL);
1118 kmem_free(ap, sizeof(*ap));
1119}
1120