1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1998-2000 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: stable/12/sys/kern/link_elf.c 371940 2022-04-10 05:02:22Z git2svn $");
31
32 #include "opt_ddb.h"
33 #include "opt_gdb.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #ifdef GPROF
38 #include <sys/gmon.h>
39 #endif
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/malloc.h>
43 #ifdef SPARSE_MAPPING
44 #include <sys/mman.h>
45 #endif
46 #include <sys/mutex.h>
47 #include <sys/mount.h>
48 #include <sys/pcpu.h>
49 #include <sys/proc.h>
50 #include <sys/namei.h>
51 #include <sys/fcntl.h>
52 #include <sys/vnode.h>
53 #include <sys/linker.h>
54
55 #include <machine/elf.h>
56
57 #include <net/vnet.h>
58
59 #include <security/mac/mac_framework.h>
60
61 #include <vm/vm.h>
62 #include <vm/vm_param.h>
63 #ifdef SPARSE_MAPPING
64 #include <vm/vm_object.h>
65 #include <vm/vm_kern.h>
66 #include <vm/vm_extern.h>
67 #endif
68 #include <vm/pmap.h>
69 #include <vm/vm_map.h>
70
71 #include <sys/link_elf.h>
72
73 #include "linker_if.h"
74
75 #define MAXSEGS 4
76
77 typedef struct elf_file {
78 struct linker_file lf; /* Common fields */
79 int preloaded; /* Was file pre-loaded */
80 caddr_t address; /* Relocation address */
81 #ifdef SPARSE_MAPPING
82 vm_object_t object; /* VM object to hold file pages */
83 #endif
84 Elf_Dyn *dynamic; /* Symbol table etc. */
85 Elf_Hashelt nbuckets; /* DT_HASH info */
86 Elf_Hashelt nchains;
87 const Elf_Hashelt *buckets;
88 const Elf_Hashelt *chains;
89 caddr_t hash;
90 caddr_t strtab; /* DT_STRTAB */
91 int strsz; /* DT_STRSZ */
92 const Elf_Sym *symtab; /* DT_SYMTAB */
93 Elf_Addr *got; /* DT_PLTGOT */
94 const Elf_Rel *pltrel; /* DT_JMPREL */
95 int pltrelsize; /* DT_PLTRELSZ */
96 const Elf_Rela *pltrela; /* DT_JMPREL */
97 int pltrelasize; /* DT_PLTRELSZ */
98 const Elf_Rel *rel; /* DT_REL */
99 int relsize; /* DT_RELSZ */
100 const Elf_Rela *rela; /* DT_RELA */
101 int relasize; /* DT_RELASZ */
102 caddr_t modptr;
103 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
104 long ddbsymcnt; /* Number of symbols */
105 caddr_t ddbstrtab; /* String table */
106 long ddbstrcnt; /* number of bytes in string table */
107 caddr_t symbase; /* malloc'ed symbold base */
108 caddr_t strbase; /* malloc'ed string base */
109 caddr_t ctftab; /* CTF table */
110 long ctfcnt; /* number of bytes in CTF table */
111 caddr_t ctfoff; /* CTF offset table */
112 caddr_t typoff; /* Type offset table */
113 long typlen; /* Number of type entries. */
114 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
115 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
116 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
117 #ifdef VIMAGE
118 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
119 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
120 Elf_Addr vnet_base; /* Relocated vnet set address. */
121 #endif
122 #ifdef GDB
123 struct link_map gdb; /* hooks for gdb */
124 #endif
125 } *elf_file_t;
126
127 struct elf_set {
128 Elf_Addr es_start;
129 Elf_Addr es_stop;
130 Elf_Addr es_base;
131 TAILQ_ENTRY(elf_set) es_link;
132 };
133
134 TAILQ_HEAD(elf_set_head, elf_set);
135
136 #include <kern/kern_ctf.c>
137
138 static int link_elf_link_common_finish(linker_file_t);
139 static int link_elf_link_preload(linker_class_t cls,
140 const char *, linker_file_t *);
141 static int link_elf_link_preload_finish(linker_file_t);
142 static int link_elf_load_file(linker_class_t, const char *,
143 linker_file_t *);
144 static int link_elf_lookup_symbol(linker_file_t, const char *,
145 c_linker_sym_t *);
146 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
147 linker_symval_t *);
148 static int link_elf_search_symbol(linker_file_t, caddr_t,
149 c_linker_sym_t *, long *);
150
151 static void link_elf_unload_file(linker_file_t);
152 static void link_elf_unload_preload(linker_file_t);
153 static int link_elf_lookup_set(linker_file_t, const char *,
154 void ***, void ***, int *);
155 static int link_elf_each_function_name(linker_file_t,
156 int (*)(const char *, void *), void *);
157 static int link_elf_each_function_nameval(linker_file_t,
158 linker_function_nameval_callback_t, void *);
159 static void link_elf_reloc_local(linker_file_t);
160 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
161 static long link_elf_strtab_get(linker_file_t, caddr_t *);
162 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
163
164 static kobj_method_t link_elf_methods[] = {
165 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
166 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
167 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
168 KOBJMETHOD(linker_unload, link_elf_unload_file),
169 KOBJMETHOD(linker_load_file, link_elf_load_file),
170 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
171 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
172 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
173 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
174 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
175 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
176 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
177 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
178 KOBJMETHOD_END
179 };
180
181 static struct linker_class link_elf_class = {
182 #if ELF_TARG_CLASS == ELFCLASS32
183 "elf32",
184 #else
185 "elf64",
186 #endif
187 link_elf_methods, sizeof(struct elf_file)
188 };
189
190 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
191 const void *data, int type, elf_lookup_fn lookup);
192
193 static int parse_dynamic(elf_file_t);
194 static int relocate_file(elf_file_t);
195 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
196 elf_reloc_fn reloc, bool ifuncs);
197 static int link_elf_preload_parse_symbols(elf_file_t);
198
199 static struct elf_set_head set_pcpu_list;
200 #ifdef VIMAGE
201 static struct elf_set_head set_vnet_list;
202 #endif
203
204 static void
elf_set_add(struct elf_set_head * list,Elf_Addr start,Elf_Addr stop,Elf_Addr base)205 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
206 {
207 struct elf_set *set, *iter;
208
209 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
210 set->es_start = start;
211 set->es_stop = stop;
212 set->es_base = base;
213
214 TAILQ_FOREACH(iter, list, es_link) {
215
216 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
217 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
218 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
219 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
220 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
221
222 if (iter->es_start > set->es_start) {
223 TAILQ_INSERT_BEFORE(iter, set, es_link);
224 break;
225 }
226 }
227
228 if (iter == NULL)
229 TAILQ_INSERT_TAIL(list, set, es_link);
230 }
231
232 static int
elf_set_find(struct elf_set_head * list,Elf_Addr addr,Elf_Addr * start,Elf_Addr * base)233 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
234 {
235 struct elf_set *set;
236
237 TAILQ_FOREACH(set, list, es_link) {
238 if (addr < set->es_start)
239 return (0);
240 if (addr < set->es_stop) {
241 *start = set->es_start;
242 *base = set->es_base;
243 return (1);
244 }
245 }
246
247 return (0);
248 }
249
250 static void
elf_set_delete(struct elf_set_head * list,Elf_Addr start)251 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
252 {
253 struct elf_set *set;
254
255 TAILQ_FOREACH(set, list, es_link) {
256 if (start < set->es_start)
257 break;
258 if (start == set->es_start) {
259 TAILQ_REMOVE(list, set, es_link);
260 free(set, M_LINKER);
261 return;
262 }
263 }
264 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
265 (uintmax_t)start));
266 }
267
268 #ifdef GDB
269 static void r_debug_state(struct r_debug *, struct link_map *);
270
271 /*
272 * A list of loaded modules for GDB to use for loading symbols.
273 */
274 struct r_debug r_debug;
275
276 #define GDB_STATE(s) do { \
277 r_debug.r_state = s; r_debug_state(NULL, NULL); \
278 } while (0)
279
280 /*
281 * Function for the debugger to set a breakpoint on to gain control.
282 */
283 static void
r_debug_state(struct r_debug * dummy_one __unused,struct link_map * dummy_two __unused)284 r_debug_state(struct r_debug *dummy_one __unused,
285 struct link_map *dummy_two __unused)
286 {
287 }
288
289 static void
link_elf_add_gdb(struct link_map * l)290 link_elf_add_gdb(struct link_map *l)
291 {
292 struct link_map *prev;
293
294 l->l_next = NULL;
295
296 if (r_debug.r_map == NULL) {
297 /* Add first. */
298 l->l_prev = NULL;
299 r_debug.r_map = l;
300 } else {
301 /* Append to list. */
302 for (prev = r_debug.r_map;
303 prev->l_next != NULL;
304 prev = prev->l_next)
305 ;
306 l->l_prev = prev;
307 prev->l_next = l;
308 }
309 }
310
311 static void
link_elf_delete_gdb(struct link_map * l)312 link_elf_delete_gdb(struct link_map *l)
313 {
314 if (l->l_prev == NULL) {
315 /* Remove first. */
316 if ((r_debug.r_map = l->l_next) != NULL)
317 l->l_next->l_prev = NULL;
318 } else {
319 /* Remove any but first. */
320 if ((l->l_prev->l_next = l->l_next) != NULL)
321 l->l_next->l_prev = l->l_prev;
322 }
323 }
324 #endif /* GDB */
325
326 /*
327 * The kernel symbol table starts here.
328 */
329 extern struct _dynamic _DYNAMIC;
330
331 static void
link_elf_error(const char * filename,const char * s)332 link_elf_error(const char *filename, const char *s)
333 {
334 if (filename == NULL)
335 printf("kldload: %s\n", s);
336 else
337 printf("kldload: %s: %s\n", filename, s);
338 }
339
340 static void
link_elf_invoke_ctors(caddr_t addr,size_t size)341 link_elf_invoke_ctors(caddr_t addr, size_t size)
342 {
343 void (**ctor)(void);
344 size_t i, cnt;
345
346 if (addr == NULL || size == 0)
347 return;
348 cnt = size / sizeof(*ctor);
349 ctor = (void *)addr;
350 for (i = 0; i < cnt; i++) {
351 if (ctor[i] != NULL)
352 (*ctor[i])();
353 }
354 }
355
356 /*
357 * Actions performed after linking/loading both the preloaded kernel and any
358 * modules; whether preloaded or dynamicly loaded.
359 */
360 static int
link_elf_link_common_finish(linker_file_t lf)361 link_elf_link_common_finish(linker_file_t lf)
362 {
363 #ifdef GDB
364 elf_file_t ef = (elf_file_t)lf;
365 char *newfilename;
366 #endif
367 int error;
368
369 /* Notify MD code that a module is being loaded. */
370 error = elf_cpu_load_file(lf);
371 if (error != 0)
372 return (error);
373
374 #ifdef GDB
375 GDB_STATE(RT_ADD);
376 ef->gdb.l_addr = lf->address;
377 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
378 strcpy(newfilename, lf->filename);
379 ef->gdb.l_name = newfilename;
380 ef->gdb.l_ld = ef->dynamic;
381 link_elf_add_gdb(&ef->gdb);
382 GDB_STATE(RT_CONSISTENT);
383 #endif
384
385 /* Invoke .ctors */
386 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
387 return (0);
388 }
389
390 extern vm_offset_t __startkernel, __endkernel;
391
392 static void
link_elf_init(void * arg)393 link_elf_init(void* arg)
394 {
395 Elf_Dyn *dp;
396 Elf_Addr *ctors_addrp;
397 Elf_Size *ctors_sizep;
398 caddr_t modptr, baseptr, sizeptr;
399 elf_file_t ef;
400 char *modname;
401
402 linker_add_class(&link_elf_class);
403
404 dp = (Elf_Dyn *)&_DYNAMIC;
405 modname = NULL;
406 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
407 if (modptr == NULL)
408 modptr = preload_search_by_type("elf kernel");
409 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
410 if (modname == NULL)
411 modname = "kernel";
412 linker_kernel_file = linker_make_file(modname, &link_elf_class);
413 if (linker_kernel_file == NULL)
414 panic("%s: Can't create linker structures for kernel",
415 __func__);
416
417 ef = (elf_file_t) linker_kernel_file;
418 ef->preloaded = 1;
419 #ifdef __powerpc__
420 ef->address = (caddr_t) (__startkernel - KERNBASE);
421 #else
422 ef->address = 0;
423 #endif
424 #ifdef SPARSE_MAPPING
425 ef->object = NULL;
426 #endif
427 ef->dynamic = dp;
428
429 if (dp != NULL)
430 parse_dynamic(ef);
431 #ifdef __powerpc__
432 linker_kernel_file->address = (caddr_t)__startkernel;
433 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
434 #else
435 linker_kernel_file->address += KERNBASE;
436 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
437 #endif
438
439 if (modptr != NULL) {
440 ef->modptr = modptr;
441 baseptr = preload_search_info(modptr, MODINFO_ADDR);
442 if (baseptr != NULL)
443 linker_kernel_file->address = *(caddr_t *)baseptr;
444 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
445 if (sizeptr != NULL)
446 linker_kernel_file->size = *(size_t *)sizeptr;
447 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
448 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
449 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
450 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
451 if (ctors_addrp != NULL && ctors_sizep != NULL) {
452 linker_kernel_file->ctors_addr = ef->address +
453 *ctors_addrp;
454 linker_kernel_file->ctors_size = *ctors_sizep;
455 }
456 }
457 (void)link_elf_preload_parse_symbols(ef);
458
459 #ifdef GDB
460 r_debug.r_map = NULL;
461 r_debug.r_brk = r_debug_state;
462 r_debug.r_state = RT_CONSISTENT;
463 #endif
464
465 (void)link_elf_link_common_finish(linker_kernel_file);
466 linker_kernel_file->flags |= LINKER_FILE_LINKED;
467 TAILQ_INIT(&set_pcpu_list);
468 #ifdef VIMAGE
469 TAILQ_INIT(&set_vnet_list);
470 #endif
471 }
472
473 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
474
475 static int
link_elf_preload_parse_symbols(elf_file_t ef)476 link_elf_preload_parse_symbols(elf_file_t ef)
477 {
478 caddr_t pointer;
479 caddr_t ssym, esym, base;
480 caddr_t strtab;
481 int strcnt;
482 Elf_Sym *symtab;
483 int symcnt;
484
485 if (ef->modptr == NULL)
486 return (0);
487 pointer = preload_search_info(ef->modptr,
488 MODINFO_METADATA | MODINFOMD_SSYM);
489 if (pointer == NULL)
490 return (0);
491 ssym = *(caddr_t *)pointer;
492 pointer = preload_search_info(ef->modptr,
493 MODINFO_METADATA | MODINFOMD_ESYM);
494 if (pointer == NULL)
495 return (0);
496 esym = *(caddr_t *)pointer;
497
498 base = ssym;
499
500 symcnt = *(long *)base;
501 base += sizeof(long);
502 symtab = (Elf_Sym *)base;
503 base += roundup(symcnt, sizeof(long));
504
505 if (base > esym || base < ssym) {
506 printf("Symbols are corrupt!\n");
507 return (EINVAL);
508 }
509
510 strcnt = *(long *)base;
511 base += sizeof(long);
512 strtab = base;
513 base += roundup(strcnt, sizeof(long));
514
515 if (base > esym || base < ssym) {
516 printf("Symbols are corrupt!\n");
517 return (EINVAL);
518 }
519
520 ef->ddbsymtab = symtab;
521 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
522 ef->ddbstrtab = strtab;
523 ef->ddbstrcnt = strcnt;
524
525 return (0);
526 }
527
528 static int
parse_dynamic(elf_file_t ef)529 parse_dynamic(elf_file_t ef)
530 {
531 Elf_Dyn *dp;
532 int plttype = DT_REL;
533
534 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
535 switch (dp->d_tag) {
536 case DT_HASH:
537 {
538 /* From src/libexec/rtld-elf/rtld.c */
539 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
540 (ef->address + dp->d_un.d_ptr);
541 ef->nbuckets = hashtab[0];
542 ef->nchains = hashtab[1];
543 ef->buckets = hashtab + 2;
544 ef->chains = ef->buckets + ef->nbuckets;
545 break;
546 }
547 case DT_STRTAB:
548 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
549 break;
550 case DT_STRSZ:
551 ef->strsz = dp->d_un.d_val;
552 break;
553 case DT_SYMTAB:
554 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
555 break;
556 case DT_SYMENT:
557 if (dp->d_un.d_val != sizeof(Elf_Sym))
558 return (ENOEXEC);
559 break;
560 case DT_PLTGOT:
561 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
562 break;
563 case DT_REL:
564 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
565 break;
566 case DT_RELSZ:
567 ef->relsize = dp->d_un.d_val;
568 break;
569 case DT_RELENT:
570 if (dp->d_un.d_val != sizeof(Elf_Rel))
571 return (ENOEXEC);
572 break;
573 case DT_JMPREL:
574 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
575 break;
576 case DT_PLTRELSZ:
577 ef->pltrelsize = dp->d_un.d_val;
578 break;
579 case DT_RELA:
580 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
581 break;
582 case DT_RELASZ:
583 ef->relasize = dp->d_un.d_val;
584 break;
585 case DT_RELAENT:
586 if (dp->d_un.d_val != sizeof(Elf_Rela))
587 return (ENOEXEC);
588 break;
589 case DT_PLTREL:
590 plttype = dp->d_un.d_val;
591 if (plttype != DT_REL && plttype != DT_RELA)
592 return (ENOEXEC);
593 break;
594 #ifdef GDB
595 case DT_DEBUG:
596 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
597 break;
598 #endif
599 }
600 }
601
602 if (plttype == DT_RELA) {
603 ef->pltrela = (const Elf_Rela *)ef->pltrel;
604 ef->pltrel = NULL;
605 ef->pltrelasize = ef->pltrelsize;
606 ef->pltrelsize = 0;
607 }
608
609 ef->ddbsymtab = ef->symtab;
610 ef->ddbsymcnt = ef->nchains;
611 ef->ddbstrtab = ef->strtab;
612 ef->ddbstrcnt = ef->strsz;
613
614 return (0);
615 }
616
617 static int
parse_dpcpu(elf_file_t ef)618 parse_dpcpu(elf_file_t ef)
619 {
620 int error, size;
621
622 ef->pcpu_start = 0;
623 ef->pcpu_stop = 0;
624 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
625 (void ***)&ef->pcpu_stop, NULL);
626 /* Error just means there is no pcpu set to relocate. */
627 if (error != 0)
628 return (0);
629 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
630 /* Empty set? */
631 if (size < 1)
632 return (0);
633 /*
634 * Allocate space in the primary pcpu area. Copy in our
635 * initialization from the data section and then initialize
636 * all per-cpu storage from that.
637 */
638 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
639 if (ef->pcpu_base == 0) {
640 printf("%s: pcpu module space is out of space; "
641 "cannot allocate %d for %s\n",
642 __func__, size, ef->lf.pathname);
643 return (ENOSPC);
644 }
645 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
646 dpcpu_copy((void *)ef->pcpu_base, size);
647 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
648 ef->pcpu_base);
649
650 return (0);
651 }
652
653 #ifdef VIMAGE
654 static int
parse_vnet(elf_file_t ef)655 parse_vnet(elf_file_t ef)
656 {
657 int error, size;
658
659 ef->vnet_start = 0;
660 ef->vnet_stop = 0;
661 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
662 (void ***)&ef->vnet_stop, NULL);
663 /* Error just means there is no vnet data set to relocate. */
664 if (error != 0)
665 return (0);
666 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
667 /* Empty set? */
668 if (size < 1)
669 return (0);
670 /*
671 * Allocate space in the primary vnet area. Copy in our
672 * initialization from the data section and then initialize
673 * all per-vnet storage from that.
674 */
675 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
676 if (ef->vnet_base == 0) {
677 printf("%s: vnet module space is out of space; "
678 "cannot allocate %d for %s\n",
679 __func__, size, ef->lf.pathname);
680 return (ENOSPC);
681 }
682 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
683 vnet_data_copy((void *)ef->vnet_base, size);
684 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
685 ef->vnet_base);
686
687 return (0);
688 }
689 #endif
690
691 #ifdef __arm__
692 /*
693 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
694 * searching for the section header that describes it. There may be no unwind
695 * info, for example in a module containing only data.
696 */
697 static void
link_elf_locate_exidx(linker_file_t lf,Elf_Shdr * shdr,int nhdr)698 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
699 {
700 int i;
701
702 for (i = 0; i < nhdr; i++) {
703 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
704 lf->exidx_addr = shdr[i].sh_addr + lf->address;
705 lf->exidx_size = shdr[i].sh_size;
706 break;
707 }
708 }
709 }
710
711 /*
712 * Locate the section headers metadata in a preloaded module, then use it to
713 * locate the exception/unwind table in the module. The size of the metadata
714 * block is stored in a uint32 word immediately before the data itself, and a
715 * comment in preload_search_info() says it is safe to rely on that.
716 */
717 static void
link_elf_locate_exidx_preload(struct linker_file * lf,caddr_t modptr)718 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
719 {
720 uint32_t *modinfo;
721 Elf_Shdr *shdr;
722 uint32_t nhdr;
723
724 modinfo = (uint32_t *)preload_search_info(modptr,
725 MODINFO_METADATA | MODINFOMD_SHDR);
726 if (modinfo != NULL) {
727 shdr = (Elf_Shdr *)modinfo;
728 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
729 link_elf_locate_exidx(lf, shdr, nhdr);
730 }
731 }
732
733 #endif /* __arm__ */
734
735 static int
link_elf_link_preload(linker_class_t cls,const char * filename,linker_file_t * result)736 link_elf_link_preload(linker_class_t cls,
737 const char* filename, linker_file_t *result)
738 {
739 Elf_Addr *ctors_addrp;
740 Elf_Size *ctors_sizep;
741 caddr_t modptr, baseptr, sizeptr, dynptr;
742 char *type;
743 elf_file_t ef;
744 linker_file_t lf;
745 int error;
746 vm_offset_t dp;
747
748 /* Look to see if we have the file preloaded */
749 modptr = preload_search_by_name(filename);
750 if (modptr == NULL)
751 return (ENOENT);
752
753 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
754 baseptr = preload_search_info(modptr, MODINFO_ADDR);
755 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
756 dynptr = preload_search_info(modptr,
757 MODINFO_METADATA | MODINFOMD_DYNAMIC);
758 if (type == NULL ||
759 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
760 strcmp(type, "elf module") != 0))
761 return (EFTYPE);
762 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
763 return (EINVAL);
764
765 lf = linker_make_file(filename, &link_elf_class);
766 if (lf == NULL)
767 return (ENOMEM);
768
769 ef = (elf_file_t) lf;
770 ef->preloaded = 1;
771 ef->modptr = modptr;
772 ef->address = *(caddr_t *)baseptr;
773 #ifdef SPARSE_MAPPING
774 ef->object = NULL;
775 #endif
776 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
777 ef->dynamic = (Elf_Dyn *)dp;
778 lf->address = ef->address;
779 lf->size = *(size_t *)sizeptr;
780
781 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
782 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
783 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
784 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
785 if (ctors_addrp != NULL && ctors_sizep != NULL) {
786 lf->ctors_addr = ef->address + *ctors_addrp;
787 lf->ctors_size = *ctors_sizep;
788 }
789
790 #ifdef __arm__
791 link_elf_locate_exidx_preload(lf, modptr);
792 #endif
793
794 error = parse_dynamic(ef);
795 if (error == 0)
796 error = parse_dpcpu(ef);
797 #ifdef VIMAGE
798 if (error == 0)
799 error = parse_vnet(ef);
800 #endif
801 if (error != 0) {
802 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
803 return (error);
804 }
805 link_elf_reloc_local(lf);
806 *result = lf;
807 return (0);
808 }
809
810 static int
link_elf_link_preload_finish(linker_file_t lf)811 link_elf_link_preload_finish(linker_file_t lf)
812 {
813 elf_file_t ef;
814 int error;
815
816 ef = (elf_file_t) lf;
817 error = relocate_file(ef);
818 if (error != 0)
819 return (error);
820 (void)link_elf_preload_parse_symbols(ef);
821
822 return (link_elf_link_common_finish(lf));
823 }
824
825 static int
link_elf_load_file(linker_class_t cls,const char * filename,linker_file_t * result)826 link_elf_load_file(linker_class_t cls, const char* filename,
827 linker_file_t* result)
828 {
829 struct nameidata nd;
830 struct thread* td = curthread; /* XXX */
831 Elf_Ehdr *hdr;
832 caddr_t firstpage, segbase;
833 int nbytes, i;
834 Elf_Phdr *phdr;
835 Elf_Phdr *phlimit;
836 Elf_Phdr *segs[MAXSEGS];
837 int nsegs;
838 Elf_Phdr *phdyn;
839 caddr_t mapbase;
840 size_t mapsize;
841 Elf_Addr base_vaddr;
842 Elf_Addr base_vlimit;
843 int error = 0;
844 ssize_t resid;
845 int flags;
846 elf_file_t ef;
847 linker_file_t lf;
848 Elf_Shdr *shdr;
849 int symtabindex;
850 int symstrindex;
851 int shstrindex;
852 int symcnt;
853 int strcnt;
854 char *shstrs;
855
856 shdr = NULL;
857 lf = NULL;
858 shstrs = NULL;
859
860 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
861 flags = FREAD;
862 error = vn_open(&nd, &flags, 0, NULL);
863 if (error != 0)
864 return (error);
865 NDFREE(&nd, NDF_ONLY_PNBUF);
866 if (nd.ni_vp->v_type != VREG) {
867 error = ENOEXEC;
868 firstpage = NULL;
869 goto out;
870 }
871 #ifdef MAC
872 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
873 if (error != 0) {
874 firstpage = NULL;
875 goto out;
876 }
877 #endif
878
879 /*
880 * Read the elf header from the file.
881 */
882 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
883 hdr = (Elf_Ehdr *)firstpage;
884 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
885 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
886 &resid, td);
887 nbytes = PAGE_SIZE - resid;
888 if (error != 0)
889 goto out;
890
891 if (!IS_ELF(*hdr)) {
892 error = ENOEXEC;
893 goto out;
894 }
895
896 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
897 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
898 link_elf_error(filename, "Unsupported file layout");
899 error = ENOEXEC;
900 goto out;
901 }
902 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
903 hdr->e_version != EV_CURRENT) {
904 link_elf_error(filename, "Unsupported file version");
905 error = ENOEXEC;
906 goto out;
907 }
908 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
909 error = ENOSYS;
910 goto out;
911 }
912 if (hdr->e_machine != ELF_TARG_MACH) {
913 link_elf_error(filename, "Unsupported machine");
914 error = ENOEXEC;
915 goto out;
916 }
917
918 /*
919 * We rely on the program header being in the first page.
920 * This is not strictly required by the ABI specification, but
921 * it seems to always true in practice. And, it simplifies
922 * things considerably.
923 */
924 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
925 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
926 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
927 link_elf_error(filename, "Unreadable program headers");
928
929 /*
930 * Scan the program header entries, and save key information.
931 *
932 * We rely on there being exactly two load segments, text and data,
933 * in that order.
934 */
935 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
936 phlimit = phdr + hdr->e_phnum;
937 nsegs = 0;
938 phdyn = NULL;
939 while (phdr < phlimit) {
940 switch (phdr->p_type) {
941 case PT_LOAD:
942 if (nsegs == MAXSEGS) {
943 link_elf_error(filename, "Too many sections");
944 error = ENOEXEC;
945 goto out;
946 }
947 /*
948 * XXX: We just trust they come in right order ??
949 */
950 segs[nsegs] = phdr;
951 ++nsegs;
952 break;
953
954 case PT_DYNAMIC:
955 phdyn = phdr;
956 break;
957
958 case PT_INTERP:
959 error = ENOSYS;
960 goto out;
961 }
962
963 ++phdr;
964 }
965 if (phdyn == NULL) {
966 link_elf_error(filename, "Object is not dynamically-linked");
967 error = ENOEXEC;
968 goto out;
969 }
970 if (nsegs == 0) {
971 link_elf_error(filename, "No sections");
972 error = ENOEXEC;
973 goto out;
974 }
975
976 /*
977 * Allocate the entire address space of the object, to stake
978 * out our contiguous region, and to establish the base
979 * address for relocation.
980 */
981 base_vaddr = trunc_page(segs[0]->p_vaddr);
982 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
983 segs[nsegs - 1]->p_memsz);
984 mapsize = base_vlimit - base_vaddr;
985
986 lf = linker_make_file(filename, &link_elf_class);
987 if (lf == NULL) {
988 error = ENOMEM;
989 goto out;
990 }
991
992 ef = (elf_file_t) lf;
993 #ifdef SPARSE_MAPPING
994 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
995 0, thread0.td_ucred);
996 if (ef->object == NULL) {
997 error = ENOMEM;
998 goto out;
999 }
1000 #ifdef __amd64__
1001 mapbase = (caddr_t)KERNBASE;
1002 #else
1003 mapbase = (caddr_t)vm_map_min(kernel_map);
1004 #endif
1005 /*
1006 * Mapping protections are downgraded after relocation processing.
1007 */
1008 error = vm_map_find(kernel_map, ef->object, 0,
1009 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1010 VM_PROT_ALL, VM_PROT_ALL, 0);
1011 if (error != 0) {
1012 vm_object_deallocate(ef->object);
1013 ef->object = NULL;
1014 goto out;
1015 }
1016 #else
1017 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK);
1018 #endif
1019 ef->address = mapbase;
1020
1021 /*
1022 * Read the text and data sections and zero the bss.
1023 */
1024 for (i = 0; i < nsegs; i++) {
1025 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1026
1027 #ifdef SPARSE_MAPPING
1028 /*
1029 * Consecutive segments may have different mapping permissions,
1030 * so be strict and verify that their mappings do not overlap.
1031 */
1032 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1033 error = EINVAL;
1034 goto out;
1035 }
1036
1037 error = vm_map_wire(kernel_map,
1038 (vm_offset_t)segbase,
1039 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1040 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1041 if (error != KERN_SUCCESS) {
1042 error = ENOMEM;
1043 goto out;
1044 }
1045 #endif
1046
1047 error = vn_rdwr(UIO_READ, nd.ni_vp,
1048 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1049 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1050 &resid, td);
1051 if (error != 0)
1052 goto out;
1053 bzero(segbase + segs[i]->p_filesz,
1054 segs[i]->p_memsz - segs[i]->p_filesz);
1055 }
1056
1057 #ifdef GPROF
1058 /* Update profiling information with the new text segment. */
1059 mtx_lock(&Giant);
1060 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1061 segs[0]->p_memsz));
1062 mtx_unlock(&Giant);
1063 #endif
1064
1065 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1066
1067 lf->address = ef->address;
1068 lf->size = mapsize;
1069
1070 error = parse_dynamic(ef);
1071 if (error != 0)
1072 goto out;
1073 error = parse_dpcpu(ef);
1074 if (error != 0)
1075 goto out;
1076 #ifdef VIMAGE
1077 error = parse_vnet(ef);
1078 if (error != 0)
1079 goto out;
1080 #endif
1081 link_elf_reloc_local(lf);
1082
1083 VOP_UNLOCK(nd.ni_vp, 0);
1084 error = linker_load_dependencies(lf);
1085 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1086 if (error != 0)
1087 goto out;
1088 error = relocate_file(ef);
1089 if (error != 0)
1090 goto out;
1091
1092 #ifdef SPARSE_MAPPING
1093 /*
1094 * Downgrade permissions on text segment mappings now that relocation
1095 * processing is complete. Restrict permissions on read-only segments.
1096 */
1097 for (i = 0; i < nsegs; i++) {
1098 vm_prot_t prot;
1099
1100 if (segs[i]->p_type != PT_LOAD)
1101 continue;
1102
1103 prot = VM_PROT_READ;
1104 if ((segs[i]->p_flags & PF_W) != 0)
1105 prot |= VM_PROT_WRITE;
1106 if ((segs[i]->p_flags & PF_X) != 0)
1107 prot |= VM_PROT_EXECUTE;
1108 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1109 error = vm_map_protect(kernel_map,
1110 (vm_offset_t)segbase,
1111 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1112 prot, FALSE);
1113 if (error != KERN_SUCCESS) {
1114 error = ENOMEM;
1115 goto out;
1116 }
1117 }
1118 #endif
1119
1120 /*
1121 * Try and load the symbol table if it's present. (you can
1122 * strip it!)
1123 */
1124 nbytes = hdr->e_shnum * hdr->e_shentsize;
1125 if (nbytes == 0 || hdr->e_shoff == 0)
1126 goto nosyms;
1127 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1128 error = vn_rdwr(UIO_READ, nd.ni_vp,
1129 (caddr_t)shdr, nbytes, hdr->e_shoff,
1130 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1131 &resid, td);
1132 if (error != 0)
1133 goto out;
1134
1135 /* Read section string table */
1136 shstrindex = hdr->e_shstrndx;
1137 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1138 shdr[shstrindex].sh_size != 0) {
1139 nbytes = shdr[shstrindex].sh_size;
1140 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1141 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1142 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1143 td->td_ucred, NOCRED, &resid, td);
1144 if (error)
1145 goto out;
1146 }
1147
1148 symtabindex = -1;
1149 symstrindex = -1;
1150 for (i = 0; i < hdr->e_shnum; i++) {
1151 if (shdr[i].sh_type == SHT_SYMTAB) {
1152 symtabindex = i;
1153 symstrindex = shdr[i].sh_link;
1154 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1155 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1156 /* Record relocated address and size of .ctors. */
1157 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1158 lf->ctors_size = shdr[i].sh_size;
1159 }
1160 }
1161 if (symtabindex < 0 || symstrindex < 0)
1162 goto nosyms;
1163
1164 symcnt = shdr[symtabindex].sh_size;
1165 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1166 strcnt = shdr[symstrindex].sh_size;
1167 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1168
1169 error = vn_rdwr(UIO_READ, nd.ni_vp,
1170 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1171 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1172 &resid, td);
1173 if (error != 0)
1174 goto out;
1175 error = vn_rdwr(UIO_READ, nd.ni_vp,
1176 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1177 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1178 &resid, td);
1179 if (error != 0)
1180 goto out;
1181
1182 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1183 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1184 ef->ddbstrcnt = strcnt;
1185 ef->ddbstrtab = ef->strbase;
1186
1187 nosyms:
1188
1189 #ifdef __arm__
1190 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1191 #endif
1192
1193 error = link_elf_link_common_finish(lf);
1194 if (error != 0)
1195 goto out;
1196
1197 *result = lf;
1198
1199 out:
1200 VOP_UNLOCK(nd.ni_vp, 0);
1201 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1202 if (error != 0 && lf != NULL)
1203 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1204 free(shdr, M_LINKER);
1205 free(firstpage, M_LINKER);
1206 free(shstrs, M_LINKER);
1207
1208 return (error);
1209 }
1210
1211 Elf_Addr
elf_relocaddr(linker_file_t lf,Elf_Addr x)1212 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1213 {
1214 elf_file_t ef;
1215
1216 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1217 ("elf_relocaddr: unexpected linker file %p", lf));
1218
1219 ef = (elf_file_t)lf;
1220 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1221 return ((x - ef->pcpu_start) + ef->pcpu_base);
1222 #ifdef VIMAGE
1223 if (x >= ef->vnet_start && x < ef->vnet_stop)
1224 return ((x - ef->vnet_start) + ef->vnet_base);
1225 #endif
1226 return (x);
1227 }
1228
1229
1230 static void
link_elf_unload_file(linker_file_t file)1231 link_elf_unload_file(linker_file_t file)
1232 {
1233 elf_file_t ef = (elf_file_t) file;
1234
1235 if (ef->pcpu_base != 0) {
1236 dpcpu_free((void *)ef->pcpu_base,
1237 ef->pcpu_stop - ef->pcpu_start);
1238 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1239 }
1240 #ifdef VIMAGE
1241 if (ef->vnet_base != 0) {
1242 vnet_data_free((void *)ef->vnet_base,
1243 ef->vnet_stop - ef->vnet_start);
1244 elf_set_delete(&set_vnet_list, ef->vnet_start);
1245 }
1246 #endif
1247 #ifdef GDB
1248 if (ef->gdb.l_ld != NULL) {
1249 GDB_STATE(RT_DELETE);
1250 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1251 link_elf_delete_gdb(&ef->gdb);
1252 GDB_STATE(RT_CONSISTENT);
1253 }
1254 #endif
1255
1256 /* Notify MD code that a module is being unloaded. */
1257 elf_cpu_unload_file(file);
1258
1259 if (ef->preloaded) {
1260 link_elf_unload_preload(file);
1261 return;
1262 }
1263
1264 #ifdef SPARSE_MAPPING
1265 if (ef->object != NULL) {
1266 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1267 (vm_offset_t) ef->address
1268 + (ef->object->size << PAGE_SHIFT));
1269 }
1270 #else
1271 free(ef->address, M_LINKER);
1272 #endif
1273 free(ef->symbase, M_LINKER);
1274 free(ef->strbase, M_LINKER);
1275 free(ef->ctftab, M_LINKER);
1276 free(ef->ctfoff, M_LINKER);
1277 free(ef->typoff, M_LINKER);
1278 }
1279
1280 static void
link_elf_unload_preload(linker_file_t file)1281 link_elf_unload_preload(linker_file_t file)
1282 {
1283 if (file->pathname != NULL)
1284 preload_delete_name(file->pathname);
1285 }
1286
1287 static const char *
symbol_name(elf_file_t ef,Elf_Size r_info)1288 symbol_name(elf_file_t ef, Elf_Size r_info)
1289 {
1290 const Elf_Sym *ref;
1291
1292 if (ELF_R_SYM(r_info)) {
1293 ref = ef->symtab + ELF_R_SYM(r_info);
1294 return (ef->strtab + ref->st_name);
1295 }
1296 return (NULL);
1297 }
1298
1299 static int
symbol_type(elf_file_t ef,Elf_Size r_info)1300 symbol_type(elf_file_t ef, Elf_Size r_info)
1301 {
1302 const Elf_Sym *ref;
1303
1304 if (ELF_R_SYM(r_info)) {
1305 ref = ef->symtab + ELF_R_SYM(r_info);
1306 return (ELF_ST_TYPE(ref->st_info));
1307 }
1308 return (STT_NOTYPE);
1309 }
1310
1311 static int
relocate_file1(elf_file_t ef,elf_lookup_fn lookup,elf_reloc_fn reloc,bool ifuncs)1312 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1313 bool ifuncs)
1314 {
1315 const Elf_Rel *rel;
1316 const Elf_Rela *rela;
1317 const char *symname;
1318
1319 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1320 for ((iter) = (tbl); (iter) != NULL && \
1321 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1322 if ((symbol_type(ef, (iter)->r_info) == \
1323 STT_GNU_IFUNC || \
1324 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1325 continue; \
1326 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1327 (iter), (type), lookup)) { \
1328 symname = symbol_name(ef, (iter)->r_info); \
1329 printf("link_elf: symbol %s undefined\n", \
1330 symname); \
1331 return (ENOENT); \
1332 } \
1333 } \
1334 } while (0)
1335
1336 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1337 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1338 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1339 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1340
1341 #undef APPLY_RELOCS
1342
1343 return (0);
1344 }
1345
1346 static int
relocate_file(elf_file_t ef)1347 relocate_file(elf_file_t ef)
1348 {
1349 int error;
1350
1351 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1352 if (error == 0)
1353 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1354 return (error);
1355 }
1356
1357 /*
1358 * Hash function for symbol table lookup. Don't even think about changing
1359 * this. It is specified by the System V ABI.
1360 */
1361 static unsigned long
elf_hash(const char * name)1362 elf_hash(const char *name)
1363 {
1364 const unsigned char *p = (const unsigned char *) name;
1365 unsigned long h = 0;
1366 unsigned long g;
1367
1368 while (*p != '\0') {
1369 h = (h << 4) + *p++;
1370 if ((g = h & 0xf0000000) != 0)
1371 h ^= g >> 24;
1372 h &= ~g;
1373 }
1374 return (h);
1375 }
1376
1377 static int
link_elf_lookup_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1378 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1379 {
1380 elf_file_t ef = (elf_file_t) lf;
1381 unsigned long symnum;
1382 const Elf_Sym* symp;
1383 const char *strp;
1384 unsigned long hash;
1385 int i;
1386
1387 /* If we don't have a hash, bail. */
1388 if (ef->buckets == NULL || ef->nbuckets == 0) {
1389 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1390 return (ENOENT);
1391 }
1392
1393 /* First, search hashed global symbols */
1394 hash = elf_hash(name);
1395 symnum = ef->buckets[hash % ef->nbuckets];
1396
1397 while (symnum != STN_UNDEF) {
1398 if (symnum >= ef->nchains) {
1399 printf("%s: corrupt symbol table\n", __func__);
1400 return (ENOENT);
1401 }
1402
1403 symp = ef->symtab + symnum;
1404 if (symp->st_name == 0) {
1405 printf("%s: corrupt symbol table\n", __func__);
1406 return (ENOENT);
1407 }
1408
1409 strp = ef->strtab + symp->st_name;
1410
1411 if (strcmp(name, strp) == 0) {
1412 if (symp->st_shndx != SHN_UNDEF ||
1413 (symp->st_value != 0 &&
1414 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1415 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1416 *sym = (c_linker_sym_t) symp;
1417 return (0);
1418 }
1419 return (ENOENT);
1420 }
1421
1422 symnum = ef->chains[symnum];
1423 }
1424
1425 /* If we have not found it, look at the full table (if loaded) */
1426 if (ef->symtab == ef->ddbsymtab)
1427 return (ENOENT);
1428
1429 /* Exhaustive search */
1430 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1431 strp = ef->ddbstrtab + symp->st_name;
1432 if (strcmp(name, strp) == 0) {
1433 if (symp->st_shndx != SHN_UNDEF ||
1434 (symp->st_value != 0 &&
1435 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1436 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1437 *sym = (c_linker_sym_t) symp;
1438 return (0);
1439 }
1440 return (ENOENT);
1441 }
1442 }
1443
1444 return (ENOENT);
1445 }
1446
1447 static int
link_elf_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1448 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1449 linker_symval_t *symval)
1450 {
1451 elf_file_t ef;
1452 const Elf_Sym *es;
1453 caddr_t val;
1454
1455 ef = (elf_file_t)lf;
1456 es = (const Elf_Sym *)sym;
1457 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1458 symval->name = ef->strtab + es->st_name;
1459 val = (caddr_t)ef->address + es->st_value;
1460 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1461 val = ((caddr_t (*)(void))val)();
1462 symval->value = val;
1463 symval->size = es->st_size;
1464 return (0);
1465 }
1466 if (ef->symtab == ef->ddbsymtab)
1467 return (ENOENT);
1468 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1469 symval->name = ef->ddbstrtab + es->st_name;
1470 val = (caddr_t)ef->address + es->st_value;
1471 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1472 val = ((caddr_t (*)(void))val)();
1473 symval->value = val;
1474 symval->size = es->st_size;
1475 return (0);
1476 }
1477 return (ENOENT);
1478 }
1479
1480 static int
link_elf_search_symbol(linker_file_t lf,caddr_t value,c_linker_sym_t * sym,long * diffp)1481 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1482 c_linker_sym_t *sym, long *diffp)
1483 {
1484 elf_file_t ef = (elf_file_t) lf;
1485 u_long off = (uintptr_t) (void *) value;
1486 u_long diff = off;
1487 u_long st_value;
1488 const Elf_Sym* es;
1489 const Elf_Sym* best = NULL;
1490 int i;
1491
1492 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1493 if (es->st_name == 0)
1494 continue;
1495 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1496 if (off >= st_value) {
1497 if (off - st_value < diff) {
1498 diff = off - st_value;
1499 best = es;
1500 if (diff == 0)
1501 break;
1502 } else if (off - st_value == diff) {
1503 best = es;
1504 }
1505 }
1506 }
1507 if (best == NULL)
1508 *diffp = off;
1509 else
1510 *diffp = diff;
1511 *sym = (c_linker_sym_t) best;
1512
1513 return (0);
1514 }
1515
1516 /*
1517 * Look up a linker set on an ELF system.
1518 */
1519 static int
link_elf_lookup_set(linker_file_t lf,const char * name,void *** startp,void *** stopp,int * countp)1520 link_elf_lookup_set(linker_file_t lf, const char *name,
1521 void ***startp, void ***stopp, int *countp)
1522 {
1523 c_linker_sym_t sym;
1524 linker_symval_t symval;
1525 char *setsym;
1526 void **start, **stop;
1527 int len, error = 0, count;
1528
1529 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1530 setsym = malloc(len, M_LINKER, M_WAITOK);
1531
1532 /* get address of first entry */
1533 snprintf(setsym, len, "%s%s", "__start_set_", name);
1534 error = link_elf_lookup_symbol(lf, setsym, &sym);
1535 if (error != 0)
1536 goto out;
1537 link_elf_symbol_values(lf, sym, &symval);
1538 if (symval.value == 0) {
1539 error = ESRCH;
1540 goto out;
1541 }
1542 start = (void **)symval.value;
1543
1544 /* get address of last entry */
1545 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1546 error = link_elf_lookup_symbol(lf, setsym, &sym);
1547 if (error != 0)
1548 goto out;
1549 link_elf_symbol_values(lf, sym, &symval);
1550 if (symval.value == 0) {
1551 error = ESRCH;
1552 goto out;
1553 }
1554 stop = (void **)symval.value;
1555
1556 /* and the number of entries */
1557 count = stop - start;
1558
1559 /* and copy out */
1560 if (startp != NULL)
1561 *startp = start;
1562 if (stopp != NULL)
1563 *stopp = stop;
1564 if (countp != NULL)
1565 *countp = count;
1566
1567 out:
1568 free(setsym, M_LINKER);
1569 return (error);
1570 }
1571
1572 static int
link_elf_each_function_name(linker_file_t file,int (* callback)(const char *,void *),void * opaque)1573 link_elf_each_function_name(linker_file_t file,
1574 int (*callback)(const char *, void *), void *opaque)
1575 {
1576 elf_file_t ef = (elf_file_t)file;
1577 const Elf_Sym *symp;
1578 int i, error;
1579
1580 /* Exhaustive search */
1581 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1582 if (symp->st_value != 0 &&
1583 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1584 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1585 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1586 if (error != 0)
1587 return (error);
1588 }
1589 }
1590 return (0);
1591 }
1592
1593 static int
link_elf_each_function_nameval(linker_file_t file,linker_function_nameval_callback_t callback,void * opaque)1594 link_elf_each_function_nameval(linker_file_t file,
1595 linker_function_nameval_callback_t callback, void *opaque)
1596 {
1597 linker_symval_t symval;
1598 elf_file_t ef = (elf_file_t)file;
1599 const Elf_Sym* symp;
1600 int i, error;
1601
1602 /* Exhaustive search */
1603 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1604 if (symp->st_value != 0 &&
1605 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1606 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1607 error = link_elf_symbol_values(file,
1608 (c_linker_sym_t) symp, &symval);
1609 if (error != 0)
1610 return (error);
1611 error = callback(file, i, &symval, opaque);
1612 if (error != 0)
1613 return (error);
1614 }
1615 }
1616 return (0);
1617 }
1618
1619 const Elf_Sym *
elf_get_sym(linker_file_t lf,Elf_Size symidx)1620 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1621 {
1622 elf_file_t ef = (elf_file_t)lf;
1623
1624 if (symidx >= ef->nchains)
1625 return (NULL);
1626 return (ef->symtab + symidx);
1627 }
1628
1629 const char *
elf_get_symname(linker_file_t lf,Elf_Size symidx)1630 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1631 {
1632 elf_file_t ef = (elf_file_t)lf;
1633 const Elf_Sym *sym;
1634
1635 if (symidx >= ef->nchains)
1636 return (NULL);
1637 sym = ef->symtab + symidx;
1638 return (ef->strtab + sym->st_name);
1639 }
1640
1641 /*
1642 * Symbol lookup function that can be used when the symbol index is known (ie
1643 * in relocations). It uses the symbol index instead of doing a fully fledged
1644 * hash table based lookup when such is valid. For example for local symbols.
1645 * This is not only more efficient, it's also more correct. It's not always
1646 * the case that the symbol can be found through the hash table.
1647 */
1648 static int
elf_lookup(linker_file_t lf,Elf_Size symidx,int deps,Elf_Addr * res)1649 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1650 {
1651 elf_file_t ef = (elf_file_t)lf;
1652 const Elf_Sym *sym;
1653 const char *symbol;
1654 Elf_Addr addr, start, base;
1655
1656 /* Don't even try to lookup the symbol if the index is bogus. */
1657 if (symidx >= ef->nchains) {
1658 *res = 0;
1659 return (EINVAL);
1660 }
1661
1662 sym = ef->symtab + symidx;
1663
1664 /*
1665 * Don't do a full lookup when the symbol is local. It may even
1666 * fail because it may not be found through the hash table.
1667 */
1668 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1669 /* Force lookup failure when we have an insanity. */
1670 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1671 *res = 0;
1672 return (EINVAL);
1673 }
1674 *res = ((Elf_Addr)ef->address + sym->st_value);
1675 return (0);
1676 }
1677
1678 /*
1679 * XXX we can avoid doing a hash table based lookup for global
1680 * symbols as well. This however is not always valid, so we'll
1681 * just do it the hard way for now. Performance tweaks can
1682 * always be added.
1683 */
1684
1685 symbol = ef->strtab + sym->st_name;
1686
1687 /* Force a lookup failure if the symbol name is bogus. */
1688 if (*symbol == 0) {
1689 *res = 0;
1690 return (EINVAL);
1691 }
1692
1693 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1694 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1695 *res = 0;
1696 return (EINVAL);
1697 }
1698
1699 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1700 addr = addr - start + base;
1701 #ifdef VIMAGE
1702 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1703 addr = addr - start + base;
1704 #endif
1705 *res = addr;
1706 return (0);
1707 }
1708
1709 static void
link_elf_reloc_local(linker_file_t lf)1710 link_elf_reloc_local(linker_file_t lf)
1711 {
1712 const Elf_Rel *rellim;
1713 const Elf_Rel *rel;
1714 const Elf_Rela *relalim;
1715 const Elf_Rela *rela;
1716 elf_file_t ef = (elf_file_t)lf;
1717
1718 /* Perform relocations without addend if there are any: */
1719 if ((rel = ef->rel) != NULL) {
1720 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1721 while (rel < rellim) {
1722 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1723 ELF_RELOC_REL, elf_lookup);
1724 rel++;
1725 }
1726 }
1727
1728 /* Perform relocations with addend if there are any: */
1729 if ((rela = ef->rela) != NULL) {
1730 relalim = (const Elf_Rela *)
1731 ((const char *)ef->rela + ef->relasize);
1732 while (rela < relalim) {
1733 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1734 ELF_RELOC_RELA, elf_lookup);
1735 rela++;
1736 }
1737 }
1738 }
1739
1740 static long
link_elf_symtab_get(linker_file_t lf,const Elf_Sym ** symtab)1741 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1742 {
1743 elf_file_t ef = (elf_file_t)lf;
1744
1745 *symtab = ef->ddbsymtab;
1746
1747 if (*symtab == NULL)
1748 return (0);
1749
1750 return (ef->ddbsymcnt);
1751 }
1752
1753 static long
link_elf_strtab_get(linker_file_t lf,caddr_t * strtab)1754 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1755 {
1756 elf_file_t ef = (elf_file_t)lf;
1757
1758 *strtab = ef->ddbstrtab;
1759
1760 if (*strtab == NULL)
1761 return (0);
1762
1763 return (ef->ddbstrcnt);
1764 }
1765
1766 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
1767 /*
1768 * Use this lookup routine when performing relocations early during boot.
1769 * The generic lookup routine depends on kobj, which is not initialized
1770 * at that point.
1771 */
1772 static int
elf_lookup_ifunc(linker_file_t lf,Elf_Size symidx,int deps __unused,Elf_Addr * res)1773 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1774 Elf_Addr *res)
1775 {
1776 elf_file_t ef;
1777 const Elf_Sym *symp;
1778 caddr_t val;
1779
1780 ef = (elf_file_t)lf;
1781 symp = ef->symtab + symidx;
1782 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1783 val = (caddr_t)ef->address + symp->st_value;
1784 *res = ((Elf_Addr (*)(void))val)();
1785 return (0);
1786 }
1787 return (ENOENT);
1788 }
1789
1790 void
link_elf_ireloc(caddr_t kmdp)1791 link_elf_ireloc(caddr_t kmdp)
1792 {
1793 struct elf_file eff;
1794 elf_file_t ef;
1795
1796 ef = &eff;
1797
1798 bzero_early(ef, sizeof(*ef));
1799
1800 ef->modptr = kmdp;
1801 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1802 parse_dynamic(ef);
1803 ef->address = 0;
1804 link_elf_preload_parse_symbols(ef);
1805 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1806 }
1807 #endif
1808