1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1998-2000 Doug Rabson
5 * Copyright (c) 2004 Peter Wemm
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 #include "opt_ddb.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/fcntl.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/linker.h>
40 #include <sys/mutex.h>
41 #include <sys/mount.h>
42 #include <sys/namei.h>
43 #include <sys/proc.h>
44 #include <sys/rwlock.h>
45 #include <sys/sysctl.h>
46 #include <sys/vnode.h>
47
48 #include <machine/elf.h>
49
50 #include <net/vnet.h>
51
52 #include <security/mac/mac_framework.h>
53
54 #include <vm/vm.h>
55 #include <vm/vm_param.h>
56 #include <vm/pmap.h>
57 #include <vm/vm_extern.h>
58 #include <vm/vm_kern.h>
59 #include <vm/vm_map.h>
60 #include <vm/vm_object.h>
61 #include <vm/vm_page.h>
62 #include <vm/vm_pager.h>
63
64 #include <sys/link_elf.h>
65
66 #ifdef DDB_CTF
67 #include <contrib/zlib/zlib.h>
68 #endif
69
70 #include "linker_if.h"
71
72 typedef struct {
73 void *addr;
74 Elf_Off size;
75 int flags; /* Section flags. */
76 int sec; /* Original section number. */
77 char *name;
78 } Elf_progent;
79
80 typedef struct {
81 Elf_Rel *rel;
82 int nrel;
83 int sec;
84 } Elf_relent;
85
86 typedef struct {
87 Elf_Rela *rela;
88 int nrela;
89 int sec;
90 } Elf_relaent;
91
92 typedef struct elf_file {
93 struct linker_file lf; /* Common fields */
94
95 int preloaded;
96 caddr_t address; /* Relocation address */
97 vm_object_t object; /* VM object to hold file pages */
98 Elf_Shdr *e_shdr;
99
100 Elf_progent *progtab;
101 u_int nprogtab;
102
103 Elf_relaent *relatab;
104 u_int nrelatab;
105
106 Elf_relent *reltab;
107 int nreltab;
108
109 Elf_Sym *ddbsymtab; /* The symbol table we are using */
110 long ddbsymcnt; /* Number of symbols */
111 caddr_t ddbstrtab; /* String table */
112 long ddbstrcnt; /* number of bytes in string table */
113
114 caddr_t shstrtab; /* Section name string table */
115 long shstrcnt; /* number of bytes in string table */
116
117 caddr_t ctftab; /* CTF table */
118 long ctfcnt; /* number of bytes in CTF table */
119 caddr_t ctfoff; /* CTF offset table */
120 caddr_t typoff; /* Type offset table */
121 long typlen; /* Number of type entries. */
122
123 } *elf_file_t;
124
125 #include <kern/kern_ctf.c>
126
127 static int link_elf_link_preload(linker_class_t cls,
128 const char *, linker_file_t *);
129 static int link_elf_link_preload_finish(linker_file_t);
130 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *);
131 static int link_elf_lookup_symbol(linker_file_t, const char *,
132 c_linker_sym_t *);
133 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
134 c_linker_sym_t *);
135 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
136 linker_symval_t *);
137 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
138 linker_symval_t *);
139 static int link_elf_search_symbol(linker_file_t, caddr_t value,
140 c_linker_sym_t *sym, long *diffp);
141
142 static void link_elf_unload_file(linker_file_t);
143 static int link_elf_lookup_set(linker_file_t, const char *,
144 void ***, void ***, int *);
145 static int link_elf_each_function_name(linker_file_t,
146 int (*)(const char *, void *), void *);
147 static int link_elf_each_function_nameval(linker_file_t,
148 linker_function_nameval_callback_t,
149 void *);
150 static int link_elf_reloc_local(linker_file_t, bool);
151 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
152 static long link_elf_strtab_get(linker_file_t, caddr_t *);
153
154 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
155 Elf_Addr *);
156
157 static kobj_method_t link_elf_methods[] = {
158 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
159 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
160 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
161 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
162 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
163 KOBJMETHOD(linker_unload, link_elf_unload_file),
164 KOBJMETHOD(linker_load_file, link_elf_load_file),
165 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
166 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
167 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
168 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
169 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
170 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
171 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
172 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
173 KOBJMETHOD_END
174 };
175
176 static struct linker_class link_elf_class = {
177 #if ELF_TARG_CLASS == ELFCLASS32
178 "elf32_obj",
179 #else
180 "elf64_obj",
181 #endif
182 link_elf_methods, sizeof(struct elf_file)
183 };
184
185 static bool link_elf_obj_leak_locals = true;
186 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_obj_leak_locals,
187 CTLFLAG_RWTUN, &link_elf_obj_leak_locals, 0,
188 "Allow local symbols to participate in global module symbol resolution");
189
190 static int relocate_file(elf_file_t ef);
191 static void elf_obj_cleanup_globals_cache(elf_file_t);
192
193 static void
link_elf_error(const char * filename,const char * s)194 link_elf_error(const char *filename, const char *s)
195 {
196 if (filename == NULL)
197 printf("kldload: %s\n", s);
198 else
199 printf("kldload: %s: %s\n", filename, s);
200 }
201
202 static void
link_elf_init(void * arg)203 link_elf_init(void *arg)
204 {
205
206 linker_add_class(&link_elf_class);
207 }
208 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);
209
210 static void
link_elf_protect_range(elf_file_t ef,vm_offset_t start,vm_offset_t end,vm_prot_t prot)211 link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end,
212 vm_prot_t prot)
213 {
214 int error __unused;
215
216 KASSERT(start <= end && start >= (vm_offset_t)ef->address &&
217 end <= round_page((vm_offset_t)ef->address + ef->lf.size),
218 ("link_elf_protect_range: invalid range %#jx-%#jx",
219 (uintmax_t)start, (uintmax_t)end));
220
221 if (start == end)
222 return;
223 if (ef->preloaded) {
224 #ifdef __amd64__
225 error = pmap_change_prot(start, end - start, prot);
226 KASSERT(error == 0,
227 ("link_elf_protect_range: pmap_change_prot() returned %d",
228 error));
229 #endif
230 return;
231 }
232 error = vm_map_protect(kernel_map, start, end, prot, 0,
233 VM_MAP_PROTECT_SET_PROT);
234 KASSERT(error == KERN_SUCCESS,
235 ("link_elf_protect_range: vm_map_protect() returned %d", error));
236 }
237
238 /*
239 * Restrict permissions on linker file memory based on section flags.
240 * Sections need not be page-aligned, so overlap within a page is possible.
241 */
242 static void
link_elf_protect(elf_file_t ef)243 link_elf_protect(elf_file_t ef)
244 {
245 vm_offset_t end, segend, segstart, start;
246 vm_prot_t gapprot, prot, segprot;
247 int i;
248
249 /*
250 * If the file was preloaded, the last page may contain other preloaded
251 * data which may need to be writeable. ELF files are always
252 * page-aligned, but other preloaded data, such as entropy or CPU
253 * microcode may be loaded with a smaller alignment.
254 */
255 gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ;
256
257 start = end = (vm_offset_t)ef->address;
258 prot = VM_PROT_READ;
259 for (i = 0; i < ef->nprogtab; i++) {
260 /*
261 * VNET and DPCPU sections have their memory allocated by their
262 * respective subsystems.
263 */
264 if (ef->progtab[i].name != NULL && (
265 #ifdef VIMAGE
266 strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 ||
267 #endif
268 strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0))
269 continue;
270
271 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr);
272 segend = round_page((vm_offset_t)ef->progtab[i].addr +
273 ef->progtab[i].size);
274 segprot = VM_PROT_READ;
275 if ((ef->progtab[i].flags & SHF_WRITE) != 0)
276 segprot |= VM_PROT_WRITE;
277 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0)
278 segprot |= VM_PROT_EXECUTE;
279
280 if (end <= segstart) {
281 /*
282 * Case 1: there is no overlap between the previous
283 * segment and this one. Apply protections to the
284 * previous segment, and protect the gap between the
285 * previous and current segments, if any.
286 */
287 link_elf_protect_range(ef, start, end, prot);
288 link_elf_protect_range(ef, end, segstart, gapprot);
289
290 start = segstart;
291 end = segend;
292 prot = segprot;
293 } else if (start < segstart && end == segend) {
294 /*
295 * Case 2: the current segment is a subrange of the
296 * previous segment. Apply protections to the
297 * non-overlapping portion of the previous segment.
298 */
299 link_elf_protect_range(ef, start, segstart, prot);
300
301 start = segstart;
302 prot |= segprot;
303 } else if (end < segend) {
304 /*
305 * Case 3: there is partial overlap between the previous
306 * and current segments. Apply protections to the
307 * non-overlapping portion of the previous segment, and
308 * then the overlap, which must use the union of the two
309 * segments' protections.
310 */
311 link_elf_protect_range(ef, start, segstart, prot);
312 link_elf_protect_range(ef, segstart, end,
313 prot | segprot);
314 start = end;
315 end = segend;
316 prot = segprot;
317 } else {
318 /*
319 * Case 4: the two segments reside in the same page.
320 */
321 prot |= segprot;
322 }
323 }
324
325 /*
326 * Fix up the last unprotected segment and trailing data.
327 */
328 link_elf_protect_range(ef, start, end, prot);
329 link_elf_protect_range(ef, end,
330 round_page((vm_offset_t)ef->address + ef->lf.size), gapprot);
331 }
332
333 static int
link_elf_link_preload(linker_class_t cls,const char * filename,linker_file_t * result)334 link_elf_link_preload(linker_class_t cls, const char *filename,
335 linker_file_t *result)
336 {
337 Elf_Ehdr *hdr;
338 Elf_Shdr *shdr;
339 Elf_Sym *es;
340 void *modptr, *baseptr, *sizeptr;
341 char *type;
342 elf_file_t ef;
343 linker_file_t lf;
344 Elf_Addr off;
345 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
346
347 /* Look to see if we have the file preloaded */
348 modptr = preload_search_by_name(filename);
349 if (modptr == NULL)
350 return ENOENT;
351
352 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
353 baseptr = preload_search_info(modptr, MODINFO_ADDR);
354 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
355 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
356 MODINFOMD_ELFHDR);
357 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
358 MODINFOMD_SHDR);
359 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
360 " obj module") != 0 &&
361 strcmp(type, "elf obj module") != 0)) {
362 return (EFTYPE);
363 }
364 if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
365 shdr == NULL)
366 return (EINVAL);
367
368 lf = linker_make_file(filename, &link_elf_class);
369 if (lf == NULL)
370 return (ENOMEM);
371
372 ef = (elf_file_t)lf;
373 ef->preloaded = 1;
374 ef->address = *(caddr_t *)baseptr;
375 lf->address = *(caddr_t *)baseptr;
376 lf->size = *(size_t *)sizeptr;
377
378 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
379 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
380 hdr->e_ident[EI_VERSION] != EV_CURRENT ||
381 hdr->e_version != EV_CURRENT ||
382 hdr->e_type != ET_REL ||
383 hdr->e_machine != ELF_TARG_MACH) {
384 error = EFTYPE;
385 goto out;
386 }
387 ef->e_shdr = shdr;
388
389 /* Scan the section header for information and table sizing. */
390 symtabindex = -1;
391 symstrindex = -1;
392 for (i = 0; i < hdr->e_shnum; i++) {
393 switch (shdr[i].sh_type) {
394 case SHT_PROGBITS:
395 case SHT_NOBITS:
396 #ifdef __amd64__
397 case SHT_X86_64_UNWIND:
398 #endif
399 case SHT_INIT_ARRAY:
400 case SHT_FINI_ARRAY:
401 /* Ignore sections not loaded by the loader. */
402 if (shdr[i].sh_addr == 0)
403 break;
404 ef->nprogtab++;
405 break;
406 case SHT_SYMTAB:
407 symtabindex = i;
408 symstrindex = shdr[i].sh_link;
409 break;
410 case SHT_REL:
411 /*
412 * Ignore relocation tables for sections not
413 * loaded by the loader.
414 */
415 if (shdr[shdr[i].sh_info].sh_addr == 0)
416 break;
417 ef->nreltab++;
418 break;
419 case SHT_RELA:
420 if (shdr[shdr[i].sh_info].sh_addr == 0)
421 break;
422 ef->nrelatab++;
423 break;
424 }
425 }
426
427 shstrindex = hdr->e_shstrndx;
428 if (ef->nprogtab == 0 || symstrindex < 0 ||
429 symstrindex >= hdr->e_shnum ||
430 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
431 shstrindex >= hdr->e_shnum ||
432 shdr[shstrindex].sh_type != SHT_STRTAB) {
433 printf("%s: bad/missing section headers\n", filename);
434 error = ENOEXEC;
435 goto out;
436 }
437
438 /* Allocate space for tracking the load chunks */
439 if (ef->nprogtab != 0)
440 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
441 M_LINKER, M_WAITOK | M_ZERO);
442 if (ef->nreltab != 0)
443 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
444 M_LINKER, M_WAITOK | M_ZERO);
445 if (ef->nrelatab != 0)
446 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
447 M_LINKER, M_WAITOK | M_ZERO);
448 if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
449 (ef->nreltab != 0 && ef->reltab == NULL) ||
450 (ef->nrelatab != 0 && ef->relatab == NULL)) {
451 error = ENOMEM;
452 goto out;
453 }
454
455 /* XXX, relocate the sh_addr fields saved by the loader. */
456 off = 0;
457 for (i = 0; i < hdr->e_shnum; i++) {
458 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
459 off = shdr[i].sh_addr;
460 }
461 for (i = 0; i < hdr->e_shnum; i++) {
462 if (shdr[i].sh_addr != 0)
463 shdr[i].sh_addr = shdr[i].sh_addr - off +
464 (Elf_Addr)ef->address;
465 }
466
467 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
468 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
469 ef->ddbstrcnt = shdr[symstrindex].sh_size;
470 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
471 ef->shstrcnt = shdr[shstrindex].sh_size;
472 ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
473
474 /* Now fill out progtab and the relocation tables. */
475 pb = 0;
476 rl = 0;
477 ra = 0;
478 for (i = 0; i < hdr->e_shnum; i++) {
479 switch (shdr[i].sh_type) {
480 case SHT_PROGBITS:
481 case SHT_NOBITS:
482 #ifdef __amd64__
483 case SHT_X86_64_UNWIND:
484 #endif
485 case SHT_INIT_ARRAY:
486 case SHT_FINI_ARRAY:
487 if (shdr[i].sh_addr == 0)
488 break;
489 ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
490 if (shdr[i].sh_type == SHT_PROGBITS)
491 ef->progtab[pb].name = "<<PROGBITS>>";
492 #ifdef __amd64__
493 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
494 ef->progtab[pb].name = "<<UNWIND>>";
495 #endif
496 else if (shdr[i].sh_type == SHT_INIT_ARRAY)
497 ef->progtab[pb].name = "<<INIT_ARRAY>>";
498 else if (shdr[i].sh_type == SHT_FINI_ARRAY)
499 ef->progtab[pb].name = "<<FINI_ARRAY>>";
500 else
501 ef->progtab[pb].name = "<<NOBITS>>";
502 ef->progtab[pb].size = shdr[i].sh_size;
503 ef->progtab[pb].flags = shdr[i].sh_flags;
504 ef->progtab[pb].sec = i;
505 if (ef->shstrtab && shdr[i].sh_name != 0)
506 ef->progtab[pb].name =
507 ef->shstrtab + shdr[i].sh_name;
508 if (ef->progtab[pb].name != NULL &&
509 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
510 void *dpcpu;
511
512 dpcpu = dpcpu_alloc(shdr[i].sh_size);
513 if (dpcpu == NULL) {
514 printf("%s: pcpu module space is out "
515 "of space; cannot allocate %#jx "
516 "for %s\n", __func__,
517 (uintmax_t)shdr[i].sh_size,
518 filename);
519 error = ENOSPC;
520 goto out;
521 }
522 memcpy(dpcpu, ef->progtab[pb].addr,
523 ef->progtab[pb].size);
524 dpcpu_copy(dpcpu, shdr[i].sh_size);
525 ef->progtab[pb].addr = dpcpu;
526 #ifdef VIMAGE
527 } else if (ef->progtab[pb].name != NULL &&
528 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
529 void *vnet_data;
530
531 vnet_data = vnet_data_alloc(shdr[i].sh_size);
532 if (vnet_data == NULL) {
533 printf("%s: vnet module space is out "
534 "of space; cannot allocate %#jx "
535 "for %s\n", __func__,
536 (uintmax_t)shdr[i].sh_size,
537 filename);
538 error = ENOSPC;
539 goto out;
540 }
541 memcpy(vnet_data, ef->progtab[pb].addr,
542 ef->progtab[pb].size);
543 vnet_data_copy(vnet_data, shdr[i].sh_size);
544 ef->progtab[pb].addr = vnet_data;
545 #endif
546 } else if ((ef->progtab[pb].name != NULL &&
547 strcmp(ef->progtab[pb].name, ".ctors") == 0) ||
548 shdr[i].sh_type == SHT_INIT_ARRAY) {
549 if (lf->ctors_addr != 0) {
550 printf(
551 "%s: multiple ctor sections in %s\n",
552 __func__, filename);
553 } else {
554 lf->ctors_addr = ef->progtab[pb].addr;
555 lf->ctors_size = shdr[i].sh_size;
556 }
557 } else if ((ef->progtab[pb].name != NULL &&
558 strcmp(ef->progtab[pb].name, ".dtors") == 0) ||
559 shdr[i].sh_type == SHT_FINI_ARRAY) {
560 if (lf->dtors_addr != 0) {
561 printf(
562 "%s: multiple dtor sections in %s\n",
563 __func__, filename);
564 } else {
565 lf->dtors_addr = ef->progtab[pb].addr;
566 lf->dtors_size = shdr[i].sh_size;
567 }
568 }
569
570 /* Update all symbol values with the offset. */
571 for (j = 0; j < ef->ddbsymcnt; j++) {
572 es = &ef->ddbsymtab[j];
573 if (es->st_shndx != i)
574 continue;
575 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
576 }
577 pb++;
578 break;
579 case SHT_REL:
580 if (shdr[shdr[i].sh_info].sh_addr == 0)
581 break;
582 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
583 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
584 ef->reltab[rl].sec = shdr[i].sh_info;
585 rl++;
586 break;
587 case SHT_RELA:
588 if (shdr[shdr[i].sh_info].sh_addr == 0)
589 break;
590 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
591 ef->relatab[ra].nrela =
592 shdr[i].sh_size / sizeof(Elf_Rela);
593 ef->relatab[ra].sec = shdr[i].sh_info;
594 ra++;
595 break;
596 }
597 }
598 if (pb != ef->nprogtab) {
599 printf("%s: lost progbits\n", filename);
600 error = ENOEXEC;
601 goto out;
602 }
603 if (rl != ef->nreltab) {
604 printf("%s: lost reltab\n", filename);
605 error = ENOEXEC;
606 goto out;
607 }
608 if (ra != ef->nrelatab) {
609 printf("%s: lost relatab\n", filename);
610 error = ENOEXEC;
611 goto out;
612 }
613
614 /*
615 * The file needs to be writeable and executable while applying
616 * relocations. Mapping protections are applied once relocation
617 * processing is complete.
618 */
619 link_elf_protect_range(ef, (vm_offset_t)ef->address,
620 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL);
621
622 /* Local intra-module relocations */
623 error = link_elf_reloc_local(lf, false);
624 if (error != 0)
625 goto out;
626 *result = lf;
627 return (0);
628
629 out:
630 /* preload not done this way */
631 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
632 return (error);
633 }
634
635 static void
link_elf_invoke_cbs(caddr_t addr,size_t size)636 link_elf_invoke_cbs(caddr_t addr, size_t size)
637 {
638 void (**ctor)(void);
639 size_t i, cnt;
640
641 if (addr == NULL || size == 0)
642 return;
643 cnt = size / sizeof(*ctor);
644 ctor = (void *)addr;
645 for (i = 0; i < cnt; i++) {
646 if (ctor[i] != NULL)
647 (*ctor[i])();
648 }
649 }
650
651 static void
link_elf_invoke_ctors(linker_file_t lf)652 link_elf_invoke_ctors(linker_file_t lf)
653 {
654 KASSERT(lf->ctors_invoked == LF_NONE,
655 ("%s: file %s ctor state %d",
656 __func__, lf->filename, lf->ctors_invoked));
657
658 link_elf_invoke_cbs(lf->ctors_addr, lf->ctors_size);
659 lf->ctors_invoked = LF_CTORS;
660 }
661
662 static void
link_elf_invoke_dtors(linker_file_t lf)663 link_elf_invoke_dtors(linker_file_t lf)
664 {
665 KASSERT(lf->ctors_invoked != LF_DTORS,
666 ("%s: file %s ctor state %d",
667 __func__, lf->filename, lf->ctors_invoked));
668
669 if (lf->ctors_invoked == LF_CTORS) {
670 link_elf_invoke_cbs(lf->dtors_addr, lf->dtors_size);
671 lf->ctors_invoked = LF_DTORS;
672 }
673 }
674
675 static int
link_elf_link_preload_finish(linker_file_t lf)676 link_elf_link_preload_finish(linker_file_t lf)
677 {
678 elf_file_t ef;
679 int error;
680
681 ef = (elf_file_t)lf;
682 error = relocate_file(ef);
683 if (error)
684 return (error);
685
686 /* Notify MD code that a module is being loaded. */
687 error = elf_cpu_load_file(lf);
688 if (error)
689 return (error);
690
691 #if defined(__i386__) || defined(__amd64__)
692 /* Now ifuncs. */
693 error = link_elf_reloc_local(lf, true);
694 if (error != 0)
695 return (error);
696 #endif
697
698 /* Apply protections now that relocation processing is complete. */
699 link_elf_protect(ef);
700
701 link_elf_invoke_ctors(lf);
702 return (0);
703 }
704
705 static int
link_elf_load_file(linker_class_t cls,const char * filename,linker_file_t * result)706 link_elf_load_file(linker_class_t cls, const char *filename,
707 linker_file_t *result)
708 {
709 struct nameidata *nd;
710 struct thread *td = curthread; /* XXX */
711 Elf_Ehdr *hdr;
712 Elf_Shdr *shdr;
713 Elf_Sym *es;
714 int nbytes, i, j;
715 vm_offset_t mapbase;
716 size_t mapsize;
717 int error = 0;
718 ssize_t resid;
719 int flags;
720 elf_file_t ef;
721 linker_file_t lf;
722 int symtabindex;
723 int symstrindex;
724 int shstrindex;
725 int nsym;
726 int pb, rl, ra;
727 int alignmask;
728
729 shdr = NULL;
730 lf = NULL;
731 mapsize = 0;
732 hdr = NULL;
733
734 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
735 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
736 flags = FREAD;
737 error = vn_open(nd, &flags, 0, NULL);
738 if (error) {
739 free(nd, M_TEMP);
740 return error;
741 }
742 NDFREE_PNBUF(nd);
743 if (nd->ni_vp->v_type != VREG) {
744 error = ENOEXEC;
745 goto out;
746 }
747 #ifdef MAC
748 error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
749 if (error) {
750 goto out;
751 }
752 #endif
753
754 /* Read the elf header from the file. */
755 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
756 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
757 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
758 &resid, td);
759 if (error)
760 goto out;
761 if (resid != 0){
762 error = ENOEXEC;
763 goto out;
764 }
765
766 if (!IS_ELF(*hdr)) {
767 error = ENOEXEC;
768 goto out;
769 }
770
771 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
772 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
773 link_elf_error(filename, "Unsupported file layout");
774 error = ENOEXEC;
775 goto out;
776 }
777 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
778 || hdr->e_version != EV_CURRENT) {
779 link_elf_error(filename, "Unsupported file version");
780 error = ENOEXEC;
781 goto out;
782 }
783 if (hdr->e_type != ET_REL) {
784 error = ENOSYS;
785 goto out;
786 }
787 if (hdr->e_machine != ELF_TARG_MACH) {
788 link_elf_error(filename, "Unsupported machine");
789 error = ENOEXEC;
790 goto out;
791 }
792
793 lf = linker_make_file(filename, &link_elf_class);
794 if (!lf) {
795 error = ENOMEM;
796 goto out;
797 }
798 ef = (elf_file_t) lf;
799 ef->nprogtab = 0;
800 ef->e_shdr = 0;
801 ef->nreltab = 0;
802 ef->nrelatab = 0;
803
804 /* Allocate and read in the section header */
805 nbytes = hdr->e_shnum * hdr->e_shentsize;
806 if (nbytes == 0 || hdr->e_shoff == 0 ||
807 hdr->e_shentsize != sizeof(Elf_Shdr)) {
808 error = ENOEXEC;
809 goto out;
810 }
811 shdr = malloc(nbytes, M_LINKER, M_WAITOK);
812 ef->e_shdr = shdr;
813 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
814 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
815 NOCRED, &resid, td);
816 if (error)
817 goto out;
818 if (resid) {
819 error = ENOEXEC;
820 goto out;
821 }
822
823 /* Scan the section header for information and table sizing. */
824 nsym = 0;
825 symtabindex = -1;
826 symstrindex = -1;
827 for (i = 0; i < hdr->e_shnum; i++) {
828 if (shdr[i].sh_size == 0)
829 continue;
830 switch (shdr[i].sh_type) {
831 case SHT_PROGBITS:
832 case SHT_NOBITS:
833 #ifdef __amd64__
834 case SHT_X86_64_UNWIND:
835 #endif
836 case SHT_INIT_ARRAY:
837 case SHT_FINI_ARRAY:
838 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
839 break;
840 ef->nprogtab++;
841 break;
842 case SHT_SYMTAB:
843 nsym++;
844 symtabindex = i;
845 symstrindex = shdr[i].sh_link;
846 break;
847 case SHT_REL:
848 /*
849 * Ignore relocation tables for unallocated
850 * sections.
851 */
852 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
853 break;
854 ef->nreltab++;
855 break;
856 case SHT_RELA:
857 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
858 break;
859 ef->nrelatab++;
860 break;
861 case SHT_STRTAB:
862 break;
863 }
864 }
865 if (ef->nprogtab == 0) {
866 link_elf_error(filename, "file has no contents");
867 error = ENOEXEC;
868 goto out;
869 }
870 if (nsym != 1) {
871 /* Only allow one symbol table for now */
872 link_elf_error(filename,
873 "file must have exactly one symbol table");
874 error = ENOEXEC;
875 goto out;
876 }
877 if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
878 shdr[symstrindex].sh_type != SHT_STRTAB) {
879 link_elf_error(filename, "file has invalid symbol strings");
880 error = ENOEXEC;
881 goto out;
882 }
883
884 /* Allocate space for tracking the load chunks */
885 if (ef->nprogtab != 0)
886 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
887 M_LINKER, M_WAITOK | M_ZERO);
888 if (ef->nreltab != 0)
889 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
890 M_LINKER, M_WAITOK | M_ZERO);
891 if (ef->nrelatab != 0)
892 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
893 M_LINKER, M_WAITOK | M_ZERO);
894
895 if (symtabindex == -1) {
896 link_elf_error(filename, "lost symbol table index");
897 error = ENOEXEC;
898 goto out;
899 }
900 /* Allocate space for and load the symbol table */
901 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
902 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
903 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
904 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
905 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
906 &resid, td);
907 if (error)
908 goto out;
909 if (resid != 0){
910 error = EINVAL;
911 goto out;
912 }
913
914 /* Allocate space for and load the symbol strings */
915 ef->ddbstrcnt = shdr[symstrindex].sh_size;
916 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
917 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
918 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
919 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
920 &resid, td);
921 if (error)
922 goto out;
923 if (resid != 0){
924 error = EINVAL;
925 goto out;
926 }
927
928 /* Do we have a string table for the section names? */
929 shstrindex = -1;
930 if (hdr->e_shstrndx != 0 &&
931 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
932 shstrindex = hdr->e_shstrndx;
933 ef->shstrcnt = shdr[shstrindex].sh_size;
934 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
935 M_WAITOK);
936 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
937 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
938 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
939 &resid, td);
940 if (error)
941 goto out;
942 if (resid != 0){
943 error = EINVAL;
944 goto out;
945 }
946 }
947
948 /* Size up code/data(progbits) and bss(nobits). */
949 alignmask = 0;
950 for (i = 0; i < hdr->e_shnum; i++) {
951 if (shdr[i].sh_size == 0)
952 continue;
953 switch (shdr[i].sh_type) {
954 case SHT_PROGBITS:
955 case SHT_NOBITS:
956 #ifdef __amd64__
957 case SHT_X86_64_UNWIND:
958 #endif
959 case SHT_INIT_ARRAY:
960 case SHT_FINI_ARRAY:
961 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
962 break;
963 alignmask = shdr[i].sh_addralign - 1;
964 mapsize += alignmask;
965 mapsize &= ~alignmask;
966 mapsize += shdr[i].sh_size;
967 break;
968 }
969 }
970
971 /*
972 * We know how much space we need for the text/data/bss/etc.
973 * This stuff needs to be in a single chunk so that profiling etc
974 * can get the bounds and gdb can associate offsets with modules
975 */
976 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize),
977 VM_PROT_ALL, 0, thread0.td_ucred);
978 if (ef->object == NULL) {
979 error = ENOMEM;
980 goto out;
981 }
982 #if VM_NRESERVLEVEL > 0
983 vm_object_color(ef->object, 0);
984 #endif
985
986 /*
987 * In order to satisfy amd64's architectural requirements on the
988 * location of code and data in the kernel's address space, request a
989 * mapping that is above the kernel.
990 *
991 * Protections will be restricted once relocations are applied.
992 */
993 #ifdef __amd64__
994 mapbase = KERNBASE;
995 #else
996 mapbase = VM_MIN_KERNEL_ADDRESS;
997 #endif
998 error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
999 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
1000 VM_PROT_ALL, 0);
1001 if (error != KERN_SUCCESS) {
1002 vm_object_deallocate(ef->object);
1003 ef->object = NULL;
1004 error = ENOMEM;
1005 goto out;
1006 }
1007
1008 /* Wire the pages */
1009 error = vm_map_wire(kernel_map, mapbase,
1010 mapbase + round_page(mapsize),
1011 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
1012 if (error != KERN_SUCCESS) {
1013 error = ENOMEM;
1014 goto out;
1015 }
1016
1017 /* Inform the kld system about the situation */
1018 lf->address = ef->address = (caddr_t)mapbase;
1019 lf->size = mapsize;
1020
1021 /*
1022 * Now load code/data(progbits), zero bss(nobits), allocate space for
1023 * and load relocs
1024 */
1025 pb = 0;
1026 rl = 0;
1027 ra = 0;
1028 alignmask = 0;
1029 for (i = 0; i < hdr->e_shnum; i++) {
1030 if (shdr[i].sh_size == 0)
1031 continue;
1032 switch (shdr[i].sh_type) {
1033 case SHT_PROGBITS:
1034 case SHT_NOBITS:
1035 #ifdef __amd64__
1036 case SHT_X86_64_UNWIND:
1037 #endif
1038 case SHT_INIT_ARRAY:
1039 case SHT_FINI_ARRAY:
1040 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
1041 break;
1042 alignmask = shdr[i].sh_addralign - 1;
1043 mapbase += alignmask;
1044 mapbase &= ~alignmask;
1045 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
1046 ef->progtab[pb].name =
1047 ef->shstrtab + shdr[i].sh_name;
1048 if (!strcmp(ef->progtab[pb].name, ".ctors") ||
1049 shdr[i].sh_type == SHT_INIT_ARRAY) {
1050 if (lf->ctors_addr != 0) {
1051 printf(
1052 "%s: multiple ctor sections in %s\n",
1053 __func__, filename);
1054 } else {
1055 lf->ctors_addr =
1056 (caddr_t)mapbase;
1057 lf->ctors_size =
1058 shdr[i].sh_size;
1059 }
1060 } else if (!strcmp(ef->progtab[pb].name,
1061 ".dtors") ||
1062 shdr[i].sh_type == SHT_FINI_ARRAY) {
1063 if (lf->dtors_addr != 0) {
1064 printf(
1065 "%s: multiple dtor sections in %s\n",
1066 __func__, filename);
1067 } else {
1068 lf->dtors_addr =
1069 (caddr_t)mapbase;
1070 lf->dtors_size =
1071 shdr[i].sh_size;
1072 }
1073 }
1074 } else if (shdr[i].sh_type == SHT_PROGBITS)
1075 ef->progtab[pb].name = "<<PROGBITS>>";
1076 #ifdef __amd64__
1077 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
1078 ef->progtab[pb].name = "<<UNWIND>>";
1079 #endif
1080 else
1081 ef->progtab[pb].name = "<<NOBITS>>";
1082 if (ef->progtab[pb].name != NULL &&
1083 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
1084 ef->progtab[pb].addr =
1085 dpcpu_alloc(shdr[i].sh_size);
1086 if (ef->progtab[pb].addr == NULL) {
1087 printf("%s: pcpu module space is out "
1088 "of space; cannot allocate %#jx "
1089 "for %s\n", __func__,
1090 (uintmax_t)shdr[i].sh_size,
1091 filename);
1092 }
1093 }
1094 #ifdef VIMAGE
1095 else if (ef->progtab[pb].name != NULL &&
1096 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
1097 ef->progtab[pb].addr =
1098 vnet_data_alloc(shdr[i].sh_size);
1099 if (ef->progtab[pb].addr == NULL) {
1100 printf("%s: vnet module space is out "
1101 "of space; cannot allocate %#jx "
1102 "for %s\n", __func__,
1103 (uintmax_t)shdr[i].sh_size,
1104 filename);
1105 }
1106 }
1107 #endif
1108 else
1109 ef->progtab[pb].addr =
1110 (void *)(uintptr_t)mapbase;
1111 if (ef->progtab[pb].addr == NULL) {
1112 error = ENOSPC;
1113 goto out;
1114 }
1115 ef->progtab[pb].size = shdr[i].sh_size;
1116 ef->progtab[pb].flags = shdr[i].sh_flags;
1117 ef->progtab[pb].sec = i;
1118 if (shdr[i].sh_type == SHT_PROGBITS
1119 #ifdef __amd64__
1120 || shdr[i].sh_type == SHT_X86_64_UNWIND
1121 #endif
1122 ) {
1123 error = vn_rdwr(UIO_READ, nd->ni_vp,
1124 ef->progtab[pb].addr,
1125 shdr[i].sh_size, shdr[i].sh_offset,
1126 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
1127 NOCRED, &resid, td);
1128 if (error)
1129 goto out;
1130 if (resid != 0){
1131 error = EINVAL;
1132 goto out;
1133 }
1134 /* Initialize the per-cpu or vnet area. */
1135 if (ef->progtab[pb].addr != (void *)mapbase &&
1136 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
1137 dpcpu_copy(ef->progtab[pb].addr,
1138 shdr[i].sh_size);
1139 #ifdef VIMAGE
1140 else if (ef->progtab[pb].addr !=
1141 (void *)mapbase &&
1142 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
1143 vnet_data_copy(ef->progtab[pb].addr,
1144 shdr[i].sh_size);
1145 #endif
1146 } else
1147 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
1148
1149 /* Update all symbol values with the offset. */
1150 for (j = 0; j < ef->ddbsymcnt; j++) {
1151 es = &ef->ddbsymtab[j];
1152 if (es->st_shndx != i)
1153 continue;
1154 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
1155 }
1156 mapbase += shdr[i].sh_size;
1157 pb++;
1158 break;
1159 case SHT_REL:
1160 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1161 break;
1162 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
1163 M_WAITOK);
1164 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
1165 ef->reltab[rl].sec = shdr[i].sh_info;
1166 error = vn_rdwr(UIO_READ, nd->ni_vp,
1167 (void *)ef->reltab[rl].rel,
1168 shdr[i].sh_size, shdr[i].sh_offset,
1169 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1170 &resid, td);
1171 if (error)
1172 goto out;
1173 if (resid != 0){
1174 error = EINVAL;
1175 goto out;
1176 }
1177 rl++;
1178 break;
1179 case SHT_RELA:
1180 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1181 break;
1182 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
1183 M_WAITOK);
1184 ef->relatab[ra].nrela =
1185 shdr[i].sh_size / sizeof(Elf_Rela);
1186 ef->relatab[ra].sec = shdr[i].sh_info;
1187 error = vn_rdwr(UIO_READ, nd->ni_vp,
1188 (void *)ef->relatab[ra].rela,
1189 shdr[i].sh_size, shdr[i].sh_offset,
1190 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1191 &resid, td);
1192 if (error)
1193 goto out;
1194 if (resid != 0){
1195 error = EINVAL;
1196 goto out;
1197 }
1198 ra++;
1199 break;
1200 }
1201 }
1202 if (pb != ef->nprogtab) {
1203 link_elf_error(filename, "lost progbits");
1204 error = ENOEXEC;
1205 goto out;
1206 }
1207 if (rl != ef->nreltab) {
1208 link_elf_error(filename, "lost reltab");
1209 error = ENOEXEC;
1210 goto out;
1211 }
1212 if (ra != ef->nrelatab) {
1213 link_elf_error(filename, "lost relatab");
1214 error = ENOEXEC;
1215 goto out;
1216 }
1217 if (mapbase != (vm_offset_t)ef->address + mapsize) {
1218 printf(
1219 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
1220 filename != NULL ? filename : "<none>",
1221 (u_long)mapbase, ef->address, (u_long)mapsize,
1222 (u_long)(vm_offset_t)ef->address + mapsize);
1223 error = ENOMEM;
1224 goto out;
1225 }
1226
1227 /* Local intra-module relocations */
1228 error = link_elf_reloc_local(lf, false);
1229 if (error != 0)
1230 goto out;
1231
1232 /* Pull in dependencies */
1233 VOP_UNLOCK(nd->ni_vp);
1234 error = linker_load_dependencies(lf);
1235 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
1236 if (error)
1237 goto out;
1238
1239 /* External relocations */
1240 error = relocate_file(ef);
1241 if (error)
1242 goto out;
1243
1244 /* Notify MD code that a module is being loaded. */
1245 error = elf_cpu_load_file(lf);
1246 if (error)
1247 goto out;
1248
1249 #if defined(__i386__) || defined(__amd64__)
1250 /* Now ifuncs. */
1251 error = link_elf_reloc_local(lf, true);
1252 if (error != 0)
1253 goto out;
1254 #endif
1255
1256 link_elf_protect(ef);
1257 link_elf_invoke_ctors(lf);
1258 *result = lf;
1259
1260 out:
1261 VOP_UNLOCK(nd->ni_vp);
1262 vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1263 free(nd, M_TEMP);
1264 if (error && lf)
1265 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1266 free(hdr, M_LINKER);
1267
1268 return error;
1269 }
1270
1271 static void
link_elf_unload_file(linker_file_t file)1272 link_elf_unload_file(linker_file_t file)
1273 {
1274 elf_file_t ef = (elf_file_t) file;
1275 u_int i;
1276
1277 link_elf_invoke_dtors(file);
1278
1279 /* Notify MD code that a module is being unloaded. */
1280 elf_cpu_unload_file(file);
1281
1282 if (ef->progtab) {
1283 for (i = 0; i < ef->nprogtab; i++) {
1284 if (ef->progtab[i].size == 0)
1285 continue;
1286 if (ef->progtab[i].name == NULL)
1287 continue;
1288 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1289 dpcpu_free(ef->progtab[i].addr,
1290 ef->progtab[i].size);
1291 #ifdef VIMAGE
1292 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1293 vnet_data_free(ef->progtab[i].addr,
1294 ef->progtab[i].size);
1295 #endif
1296 }
1297 }
1298 if (ef->preloaded) {
1299 free(ef->reltab, M_LINKER);
1300 free(ef->relatab, M_LINKER);
1301 free(ef->progtab, M_LINKER);
1302 free(ef->ctftab, M_LINKER);
1303 free(ef->ctfoff, M_LINKER);
1304 free(ef->typoff, M_LINKER);
1305 if (file->pathname != NULL)
1306 preload_delete_name(file->pathname);
1307 return;
1308 }
1309
1310 for (i = 0; i < ef->nreltab; i++)
1311 free(ef->reltab[i].rel, M_LINKER);
1312 for (i = 0; i < ef->nrelatab; i++)
1313 free(ef->relatab[i].rela, M_LINKER);
1314 free(ef->reltab, M_LINKER);
1315 free(ef->relatab, M_LINKER);
1316 free(ef->progtab, M_LINKER);
1317
1318 if (ef->object != NULL)
1319 vm_map_remove(kernel_map, (vm_offset_t)ef->address,
1320 (vm_offset_t)ef->address + ptoa(ef->object->size));
1321 free(ef->e_shdr, M_LINKER);
1322 free(ef->ddbsymtab, M_LINKER);
1323 free(ef->ddbstrtab, M_LINKER);
1324 free(ef->shstrtab, M_LINKER);
1325 free(ef->ctftab, M_LINKER);
1326 free(ef->ctfoff, M_LINKER);
1327 free(ef->typoff, M_LINKER);
1328 }
1329
1330 static const char *
symbol_name(elf_file_t ef,Elf_Size r_info)1331 symbol_name(elf_file_t ef, Elf_Size r_info)
1332 {
1333 const Elf_Sym *ref;
1334
1335 if (ELF_R_SYM(r_info)) {
1336 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1337 return ef->ddbstrtab + ref->st_name;
1338 } else
1339 return NULL;
1340 }
1341
1342 static Elf_Addr
findbase(elf_file_t ef,int sec)1343 findbase(elf_file_t ef, int sec)
1344 {
1345 int i;
1346 Elf_Addr base = 0;
1347
1348 for (i = 0; i < ef->nprogtab; i++) {
1349 if (sec == ef->progtab[i].sec) {
1350 base = (Elf_Addr)ef->progtab[i].addr;
1351 break;
1352 }
1353 }
1354 return base;
1355 }
1356
1357 static int
relocate_file1(elf_file_t ef,bool ifuncs)1358 relocate_file1(elf_file_t ef, bool ifuncs)
1359 {
1360 const Elf_Rel *rellim;
1361 const Elf_Rel *rel;
1362 const Elf_Rela *relalim;
1363 const Elf_Rela *rela;
1364 const char *symname;
1365 const Elf_Sym *sym;
1366 int i;
1367 Elf_Size symidx;
1368 Elf_Addr base;
1369
1370 /* Perform relocations without addend if there are any: */
1371 for (i = 0; i < ef->nreltab; i++) {
1372 rel = ef->reltab[i].rel;
1373 if (rel == NULL) {
1374 link_elf_error(ef->lf.filename, "lost a reltab!");
1375 return (ENOEXEC);
1376 }
1377 rellim = rel + ef->reltab[i].nrel;
1378 base = findbase(ef, ef->reltab[i].sec);
1379 if (base == 0) {
1380 link_elf_error(ef->lf.filename, "lost base for reltab");
1381 return (ENOEXEC);
1382 }
1383 for ( ; rel < rellim; rel++) {
1384 symidx = ELF_R_SYM(rel->r_info);
1385 if (symidx >= ef->ddbsymcnt)
1386 continue;
1387 sym = ef->ddbsymtab + symidx;
1388 /* Local relocs are already done */
1389 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1390 continue;
1391 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1392 elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
1393 continue;
1394 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1395 elf_obj_lookup)) {
1396 symname = symbol_name(ef, rel->r_info);
1397 printf("link_elf_obj: symbol %s undefined\n",
1398 symname);
1399 return (ENOENT);
1400 }
1401 }
1402 }
1403
1404 /* Perform relocations with addend if there are any: */
1405 for (i = 0; i < ef->nrelatab; i++) {
1406 rela = ef->relatab[i].rela;
1407 if (rela == NULL) {
1408 link_elf_error(ef->lf.filename, "lost a relatab!");
1409 return (ENOEXEC);
1410 }
1411 relalim = rela + ef->relatab[i].nrela;
1412 base = findbase(ef, ef->relatab[i].sec);
1413 if (base == 0) {
1414 link_elf_error(ef->lf.filename,
1415 "lost base for relatab");
1416 return (ENOEXEC);
1417 }
1418 for ( ; rela < relalim; rela++) {
1419 symidx = ELF_R_SYM(rela->r_info);
1420 if (symidx >= ef->ddbsymcnt)
1421 continue;
1422 sym = ef->ddbsymtab + symidx;
1423 /* Local relocs are already done */
1424 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1425 continue;
1426 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1427 elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
1428 continue;
1429 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1430 elf_obj_lookup)) {
1431 symname = symbol_name(ef, rela->r_info);
1432 printf("link_elf_obj: symbol %s undefined\n",
1433 symname);
1434 return (ENOENT);
1435 }
1436 }
1437 }
1438
1439 /*
1440 * Only clean SHN_FBSD_CACHED for successful return. If we
1441 * modified symbol table for the object but found an
1442 * unresolved symbol, there is no reason to roll back.
1443 */
1444 elf_obj_cleanup_globals_cache(ef);
1445
1446 return (0);
1447 }
1448
1449 static int
relocate_file(elf_file_t ef)1450 relocate_file(elf_file_t ef)
1451 {
1452 int error;
1453
1454 error = relocate_file1(ef, false);
1455 if (error == 0)
1456 error = relocate_file1(ef, true);
1457 return (error);
1458 }
1459
1460 static int
link_elf_lookup_symbol1(linker_file_t lf,const char * name,c_linker_sym_t * sym,bool see_local)1461 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1462 bool see_local)
1463 {
1464 elf_file_t ef = (elf_file_t)lf;
1465 const Elf_Sym *symp;
1466 const char *strp;
1467 int i;
1468
1469 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1470 strp = ef->ddbstrtab + symp->st_name;
1471 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1472 if (see_local ||
1473 ELF_ST_BIND(symp->st_info) == STB_GLOBAL) {
1474 *sym = (c_linker_sym_t) symp;
1475 return (0);
1476 }
1477 return (ENOENT);
1478 }
1479 }
1480 return (ENOENT);
1481 }
1482
1483 static int
link_elf_lookup_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1484 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1485 {
1486 return (link_elf_lookup_symbol1(lf, name, sym,
1487 link_elf_obj_leak_locals));
1488 }
1489
1490 static int
link_elf_lookup_debug_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1491 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1492 c_linker_sym_t *sym)
1493 {
1494 return (link_elf_lookup_symbol1(lf, name, sym, true));
1495 }
1496
1497 static int
link_elf_symbol_values1(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval,bool see_local)1498 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1499 linker_symval_t *symval, bool see_local)
1500 {
1501 elf_file_t ef;
1502 const Elf_Sym *es;
1503 caddr_t val;
1504
1505 ef = (elf_file_t) lf;
1506 es = (const Elf_Sym*) sym;
1507 val = (caddr_t)es->st_value;
1508 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1509 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1510 return (ENOENT);
1511 symval->name = ef->ddbstrtab + es->st_name;
1512 val = (caddr_t)es->st_value;
1513 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1514 val = ((caddr_t (*)(void))val)();
1515 symval->value = val;
1516 symval->size = es->st_size;
1517 return (0);
1518 }
1519 return (ENOENT);
1520 }
1521
1522 static int
link_elf_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1523 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1524 linker_symval_t *symval)
1525 {
1526 return (link_elf_symbol_values1(lf, sym, symval,
1527 link_elf_obj_leak_locals));
1528 }
1529
1530 static int
link_elf_debug_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1531 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1532 linker_symval_t *symval)
1533 {
1534 return (link_elf_symbol_values1(lf, sym, symval, true));
1535 }
1536
1537 static int
link_elf_search_symbol(linker_file_t lf,caddr_t value,c_linker_sym_t * sym,long * diffp)1538 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1539 c_linker_sym_t *sym, long *diffp)
1540 {
1541 elf_file_t ef = (elf_file_t)lf;
1542 u_long off = (uintptr_t)(void *)value;
1543 u_long diff = off;
1544 u_long st_value;
1545 const Elf_Sym *es;
1546 const Elf_Sym *best = NULL;
1547 int i;
1548
1549 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1550 if (es->st_name == 0)
1551 continue;
1552 st_value = es->st_value;
1553 if (off >= st_value) {
1554 if (off - st_value < diff) {
1555 diff = off - st_value;
1556 best = es;
1557 if (diff == 0)
1558 break;
1559 } else if (off - st_value == diff) {
1560 best = es;
1561 }
1562 }
1563 }
1564 if (best == NULL)
1565 *diffp = off;
1566 else
1567 *diffp = diff;
1568 *sym = (c_linker_sym_t) best;
1569
1570 return (0);
1571 }
1572
1573 /*
1574 * Look up a linker set on an ELF system.
1575 */
1576 static int
link_elf_lookup_set(linker_file_t lf,const char * name,void *** startp,void *** stopp,int * countp)1577 link_elf_lookup_set(linker_file_t lf, const char *name,
1578 void ***startp, void ***stopp, int *countp)
1579 {
1580 elf_file_t ef = (elf_file_t)lf;
1581 void **start, **stop;
1582 int i, count;
1583
1584 /* Relative to section number */
1585 for (i = 0; i < ef->nprogtab; i++) {
1586 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1587 strcmp(ef->progtab[i].name + 4, name) == 0) {
1588 start = (void **)ef->progtab[i].addr;
1589 stop = (void **)((char *)ef->progtab[i].addr +
1590 ef->progtab[i].size);
1591 count = stop - start;
1592 if (startp)
1593 *startp = start;
1594 if (stopp)
1595 *stopp = stop;
1596 if (countp)
1597 *countp = count;
1598 return (0);
1599 }
1600 }
1601 return (ESRCH);
1602 }
1603
1604 static int
link_elf_each_function_name(linker_file_t file,int (* callback)(const char *,void *),void * opaque)1605 link_elf_each_function_name(linker_file_t file,
1606 int (*callback)(const char *, void *), void *opaque)
1607 {
1608 elf_file_t ef = (elf_file_t)file;
1609 const Elf_Sym *symp;
1610 int i, error;
1611
1612 /* Exhaustive search */
1613 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1614 if (symp->st_value != 0 &&
1615 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1616 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1617 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1618 if (error)
1619 return (error);
1620 }
1621 }
1622 return (0);
1623 }
1624
1625 static int
link_elf_each_function_nameval(linker_file_t file,linker_function_nameval_callback_t callback,void * opaque)1626 link_elf_each_function_nameval(linker_file_t file,
1627 linker_function_nameval_callback_t callback, void *opaque)
1628 {
1629 linker_symval_t symval;
1630 elf_file_t ef = (elf_file_t)file;
1631 const Elf_Sym *symp;
1632 int i, error;
1633
1634 /* Exhaustive search */
1635 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1636 if (symp->st_value != 0 &&
1637 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1638 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1639 error = link_elf_debug_symbol_values(file,
1640 (c_linker_sym_t)symp, &symval);
1641 if (error == 0)
1642 error = callback(file, i, &symval, opaque);
1643 if (error != 0)
1644 return (error);
1645 }
1646 }
1647 return (0);
1648 }
1649
1650 static void
elf_obj_cleanup_globals_cache(elf_file_t ef)1651 elf_obj_cleanup_globals_cache(elf_file_t ef)
1652 {
1653 Elf_Sym *sym;
1654 Elf_Size i;
1655
1656 for (i = 0; i < ef->ddbsymcnt; i++) {
1657 sym = ef->ddbsymtab + i;
1658 if (sym->st_shndx == SHN_FBSD_CACHED) {
1659 sym->st_shndx = SHN_UNDEF;
1660 sym->st_value = 0;
1661 }
1662 }
1663 }
1664
1665 /*
1666 * Symbol lookup function that can be used when the symbol index is known (ie
1667 * in relocations). It uses the symbol index instead of doing a fully fledged
1668 * hash table based lookup when such is valid. For example for local symbols.
1669 * This is not only more efficient, it's also more correct. It's not always
1670 * the case that the symbol can be found through the hash table.
1671 */
1672 static int
elf_obj_lookup(linker_file_t lf,Elf_Size symidx,int deps,Elf_Addr * res)1673 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1674 {
1675 elf_file_t ef = (elf_file_t)lf;
1676 Elf_Sym *sym;
1677 const char *symbol;
1678 Elf_Addr res1;
1679
1680 /* Don't even try to lookup the symbol if the index is bogus. */
1681 if (symidx >= ef->ddbsymcnt) {
1682 *res = 0;
1683 return (EINVAL);
1684 }
1685
1686 sym = ef->ddbsymtab + symidx;
1687
1688 /* Quick answer if there is a definition included. */
1689 if (sym->st_shndx != SHN_UNDEF) {
1690 res1 = (Elf_Addr)sym->st_value;
1691 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1692 res1 = ((Elf_Addr (*)(void))res1)();
1693 *res = res1;
1694 return (0);
1695 }
1696
1697 /* If we get here, then it is undefined and needs a lookup. */
1698 switch (ELF_ST_BIND(sym->st_info)) {
1699 case STB_LOCAL:
1700 /* Local, but undefined? huh? */
1701 *res = 0;
1702 return (EINVAL);
1703
1704 case STB_GLOBAL:
1705 case STB_WEAK:
1706 /* Relative to Data or Function name */
1707 symbol = ef->ddbstrtab + sym->st_name;
1708
1709 /* Force a lookup failure if the symbol name is bogus. */
1710 if (*symbol == 0) {
1711 *res = 0;
1712 return (EINVAL);
1713 }
1714 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1715
1716 /*
1717 * Cache global lookups during module relocation. The failure
1718 * case is particularly expensive for callers, who must scan
1719 * through the entire globals table doing strcmp(). Cache to
1720 * avoid doing such work repeatedly.
1721 *
1722 * After relocation is complete, undefined globals will be
1723 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1724 * above.
1725 */
1726 if (res1 != 0) {
1727 sym->st_shndx = SHN_FBSD_CACHED;
1728 sym->st_value = res1;
1729 *res = res1;
1730 return (0);
1731 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1732 sym->st_value = 0;
1733 *res = 0;
1734 return (0);
1735 }
1736 return (EINVAL);
1737
1738 default:
1739 return (EINVAL);
1740 }
1741 }
1742
1743 static void
link_elf_fix_link_set(elf_file_t ef)1744 link_elf_fix_link_set(elf_file_t ef)
1745 {
1746 static const char startn[] = "__start_";
1747 static const char stopn[] = "__stop_";
1748 Elf_Sym *sym;
1749 const char *sym_name, *linkset_name;
1750 Elf_Addr startp, stopp;
1751 Elf_Size symidx;
1752 int start, i;
1753
1754 startp = stopp = 0;
1755 for (symidx = 1 /* zero entry is special */;
1756 symidx < ef->ddbsymcnt; symidx++) {
1757 sym = ef->ddbsymtab + symidx;
1758 if (sym->st_shndx != SHN_UNDEF)
1759 continue;
1760
1761 sym_name = ef->ddbstrtab + sym->st_name;
1762 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1763 start = 1;
1764 linkset_name = sym_name + sizeof(startn) - 1;
1765 }
1766 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1767 start = 0;
1768 linkset_name = sym_name + sizeof(stopn) - 1;
1769 }
1770 else
1771 continue;
1772
1773 for (i = 0; i < ef->nprogtab; i++) {
1774 if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1775 startp = (Elf_Addr)ef->progtab[i].addr;
1776 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1777 break;
1778 }
1779 }
1780 if (i == ef->nprogtab)
1781 continue;
1782
1783 sym->st_value = start ? startp : stopp;
1784 sym->st_shndx = i;
1785 }
1786 }
1787
1788 static int
link_elf_reloc_local(linker_file_t lf,bool ifuncs)1789 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1790 {
1791 elf_file_t ef = (elf_file_t)lf;
1792 const Elf_Rel *rellim;
1793 const Elf_Rel *rel;
1794 const Elf_Rela *relalim;
1795 const Elf_Rela *rela;
1796 const Elf_Sym *sym;
1797 Elf_Addr base;
1798 int i;
1799 Elf_Size symidx;
1800
1801 link_elf_fix_link_set(ef);
1802
1803 /* Perform relocations without addend if there are any: */
1804 for (i = 0; i < ef->nreltab; i++) {
1805 rel = ef->reltab[i].rel;
1806 if (rel == NULL) {
1807 link_elf_error(ef->lf.filename, "lost a reltab");
1808 return (ENOEXEC);
1809 }
1810 rellim = rel + ef->reltab[i].nrel;
1811 base = findbase(ef, ef->reltab[i].sec);
1812 if (base == 0) {
1813 link_elf_error(ef->lf.filename, "lost base for reltab");
1814 return (ENOEXEC);
1815 }
1816 for ( ; rel < rellim; rel++) {
1817 symidx = ELF_R_SYM(rel->r_info);
1818 if (symidx >= ef->ddbsymcnt)
1819 continue;
1820 sym = ef->ddbsymtab + symidx;
1821 /* Only do local relocs */
1822 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1823 continue;
1824 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1825 elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
1826 continue;
1827 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1828 elf_obj_lookup) != 0)
1829 return (ENOEXEC);
1830 }
1831 }
1832
1833 /* Perform relocations with addend if there are any: */
1834 for (i = 0; i < ef->nrelatab; i++) {
1835 rela = ef->relatab[i].rela;
1836 if (rela == NULL) {
1837 link_elf_error(ef->lf.filename, "lost a relatab!");
1838 return (ENOEXEC);
1839 }
1840 relalim = rela + ef->relatab[i].nrela;
1841 base = findbase(ef, ef->relatab[i].sec);
1842 if (base == 0) {
1843 link_elf_error(ef->lf.filename, "lost base for reltab");
1844 return (ENOEXEC);
1845 }
1846 for ( ; rela < relalim; rela++) {
1847 symidx = ELF_R_SYM(rela->r_info);
1848 if (symidx >= ef->ddbsymcnt)
1849 continue;
1850 sym = ef->ddbsymtab + symidx;
1851 /* Only do local relocs */
1852 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1853 continue;
1854 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1855 elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
1856 continue;
1857 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1858 elf_obj_lookup) != 0)
1859 return (ENOEXEC);
1860 }
1861 }
1862 return (0);
1863 }
1864
1865 static long
link_elf_symtab_get(linker_file_t lf,const Elf_Sym ** symtab)1866 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1867 {
1868 elf_file_t ef = (elf_file_t)lf;
1869
1870 *symtab = ef->ddbsymtab;
1871 if (*symtab == NULL)
1872 return (0);
1873 return (ef->ddbsymcnt);
1874 }
1875
1876 static long
link_elf_strtab_get(linker_file_t lf,caddr_t * strtab)1877 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1878 {
1879 elf_file_t ef = (elf_file_t)lf;
1880
1881 *strtab = ef->ddbstrtab;
1882 if (*strtab == NULL)
1883 return (0);
1884 return (ef->ddbstrcnt);
1885 }
1886