1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 "opt_ddb.h"
30 #include "opt_gdb.h"
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #ifdef SPARSE_MAPPING
38 #include <sys/mman.h>
39 #endif
40 #include <sys/mutex.h>
41 #include <sys/mount.h>
42 #include <sys/pcpu.h>
43 #include <sys/proc.h>
44 #include <sys/namei.h>
45 #include <sys/fcntl.h>
46 #include <sys/vnode.h>
47 #include <sys/linker.h>
48 #include <sys/sysctl.h>
49 #include <sys/tslog.h>
50
51 #include <machine/elf.h>
52
53 #include <net/vnet.h>
54
55 #include <security/mac/mac_framework.h>
56
57 #include <vm/vm.h>
58 #include <vm/vm_param.h>
59 #ifdef SPARSE_MAPPING
60 #include <vm/vm_object.h>
61 #include <vm/vm_kern.h>
62 #include <vm/vm_extern.h>
63 #endif
64 #include <vm/pmap.h>
65 #include <vm/vm_map.h>
66
67 #include <sys/link_elf.h>
68
69 #include "linker_if.h"
70
71 #ifdef DDB_CTF
72 #include <ddb/db_ctf.h>
73 #endif
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_lookup_debug_symbol(linker_file_t, const char *,
147 c_linker_sym_t *);
148 static int link_elf_lookup_debug_symbol_ctf(linker_file_t lf,
149 const char *name, c_linker_sym_t *sym, linker_ctf_t *lc);
150 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
151 linker_symval_t *);
152 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
153 linker_symval_t*);
154 static int link_elf_search_symbol(linker_file_t, caddr_t,
155 c_linker_sym_t *, long *);
156
157 static void link_elf_unload_file(linker_file_t);
158 static void link_elf_unload_preload(linker_file_t);
159 static int link_elf_lookup_set(linker_file_t, const char *,
160 void ***, void ***, int *);
161 static int link_elf_each_function_name(linker_file_t,
162 int (*)(const char *, void *), void *);
163 static int link_elf_each_function_nameval(linker_file_t,
164 linker_function_nameval_callback_t, void *);
165 static void link_elf_reloc_local(linker_file_t);
166 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
167 static long link_elf_strtab_get(linker_file_t, caddr_t *);
168 #ifdef VIMAGE
169 static void link_elf_propagate_vnets(linker_file_t);
170 #endif
171 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
172
173 static kobj_method_t link_elf_methods[] = {
174 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
175 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
176 KOBJMETHOD(linker_lookup_debug_symbol_ctf, link_elf_lookup_debug_symbol_ctf),
177 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
178 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
179 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
180 KOBJMETHOD(linker_unload, link_elf_unload_file),
181 KOBJMETHOD(linker_load_file, link_elf_load_file),
182 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
183 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
184 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
185 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
186 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
187 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
188 KOBJMETHOD(linker_ctf_lookup_typename, link_elf_ctf_lookup_typename),
189 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
190 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
191 #ifdef VIMAGE
192 KOBJMETHOD(linker_propagate_vnets, link_elf_propagate_vnets),
193 #endif
194 KOBJMETHOD_END
195 };
196
197 static struct linker_class link_elf_class = {
198 #if ELF_TARG_CLASS == ELFCLASS32
199 "elf32",
200 #else
201 "elf64",
202 #endif
203 link_elf_methods, sizeof(struct elf_file)
204 };
205
206 static bool link_elf_leak_locals = true;
207 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
208 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
209 "Allow local symbols to participate in global module symbol resolution");
210
211 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
212 const void *data, int type, elf_lookup_fn lookup);
213
214 static int parse_dynamic(elf_file_t);
215 static int relocate_file(elf_file_t);
216 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
217 elf_reloc_fn reloc, bool ifuncs);
218 static int link_elf_preload_parse_symbols(elf_file_t);
219
220 static struct elf_set_head set_pcpu_list;
221 #ifdef VIMAGE
222 static struct elf_set_head set_vnet_list;
223 #endif
224
225 static void
elf_set_add(struct elf_set_head * list,Elf_Addr start,Elf_Addr stop,Elf_Addr base)226 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
227 {
228 struct elf_set *set, *iter;
229
230 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
231 set->es_start = start;
232 set->es_stop = stop;
233 set->es_base = base;
234
235 TAILQ_FOREACH(iter, list, es_link) {
236 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
237 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
238 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
239 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
240 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
241
242 if (iter->es_start > set->es_start) {
243 TAILQ_INSERT_BEFORE(iter, set, es_link);
244 break;
245 }
246 }
247
248 if (iter == NULL)
249 TAILQ_INSERT_TAIL(list, set, es_link);
250 }
251
252 static int
elf_set_find(struct elf_set_head * list,Elf_Addr addr,Elf_Addr * start,Elf_Addr * base)253 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
254 {
255 struct elf_set *set;
256
257 TAILQ_FOREACH(set, list, es_link) {
258 if (addr < set->es_start)
259 return (0);
260 if (addr < set->es_stop) {
261 *start = set->es_start;
262 *base = set->es_base;
263 return (1);
264 }
265 }
266
267 return (0);
268 }
269
270 static void
elf_set_delete(struct elf_set_head * list,Elf_Addr start)271 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
272 {
273 struct elf_set *set;
274
275 TAILQ_FOREACH(set, list, es_link) {
276 if (start < set->es_start)
277 break;
278 if (start == set->es_start) {
279 TAILQ_REMOVE(list, set, es_link);
280 free(set, M_LINKER);
281 return;
282 }
283 }
284 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
285 (uintmax_t)start));
286 }
287
288 #ifdef GDB
289 static void r_debug_state(struct r_debug *, struct link_map *);
290
291 /*
292 * A list of loaded modules for GDB to use for loading symbols.
293 */
294 struct r_debug r_debug;
295
296 #define GDB_STATE(s) do { \
297 r_debug.r_state = s; r_debug_state(NULL, NULL); \
298 } while (0)
299
300 /*
301 * Function for the debugger to set a breakpoint on to gain control.
302 */
303 static void
r_debug_state(struct r_debug * dummy_one __unused,struct link_map * dummy_two __unused)304 r_debug_state(struct r_debug *dummy_one __unused,
305 struct link_map *dummy_two __unused)
306 {
307 }
308
309 static void
link_elf_add_gdb(struct link_map * l)310 link_elf_add_gdb(struct link_map *l)
311 {
312 struct link_map *prev;
313
314 l->l_next = NULL;
315
316 if (r_debug.r_map == NULL) {
317 /* Add first. */
318 l->l_prev = NULL;
319 r_debug.r_map = l;
320 } else {
321 /* Append to list. */
322 for (prev = r_debug.r_map;
323 prev->l_next != NULL;
324 prev = prev->l_next)
325 ;
326 l->l_prev = prev;
327 prev->l_next = l;
328 }
329 }
330
331 static void
link_elf_delete_gdb(struct link_map * l)332 link_elf_delete_gdb(struct link_map *l)
333 {
334 if (l->l_prev == NULL) {
335 /* Remove first. */
336 if ((r_debug.r_map = l->l_next) != NULL)
337 l->l_next->l_prev = NULL;
338 } else {
339 /* Remove any but first. */
340 if ((l->l_prev->l_next = l->l_next) != NULL)
341 l->l_next->l_prev = l->l_prev;
342 }
343 }
344 #endif /* GDB */
345
346 /*
347 * The kernel symbol table starts here.
348 */
349 extern struct _dynamic _DYNAMIC;
350
351 static void
link_elf_error(const char * filename,const char * s)352 link_elf_error(const char *filename, const char *s)
353 {
354 if (filename == NULL)
355 printf("kldload: %s\n", s);
356 else
357 printf("kldload: %s: %s\n", filename, s);
358 }
359
360 static void
link_elf_invoke_cbs(caddr_t addr,size_t size)361 link_elf_invoke_cbs(caddr_t addr, size_t size)
362 {
363 void (**ctor)(void);
364 size_t i, cnt;
365
366 if (addr == NULL || size == 0)
367 return;
368 cnt = size / sizeof(*ctor);
369 ctor = (void *)addr;
370 for (i = 0; i < cnt; i++) {
371 if (ctor[i] != NULL)
372 (*ctor[i])();
373 }
374 }
375
376 static void
link_elf_invoke_ctors(linker_file_t lf)377 link_elf_invoke_ctors(linker_file_t lf)
378 {
379 KASSERT(lf->ctors_invoked == LF_NONE,
380 ("%s: file %s ctor state %d",
381 __func__, lf->filename, lf->ctors_invoked));
382
383 link_elf_invoke_cbs(lf->ctors_addr, lf->ctors_size);
384 lf->ctors_invoked = LF_CTORS;
385 }
386
387 /*
388 * Actions performed after linking/loading both the preloaded kernel and any
389 * modules; whether preloaded or dynamicly loaded.
390 */
391 static int
link_elf_link_common_finish(linker_file_t lf)392 link_elf_link_common_finish(linker_file_t lf)
393 {
394 #ifdef GDB
395 elf_file_t ef = (elf_file_t)lf;
396 char *newfilename;
397 #endif
398 int error;
399
400 /* Notify MD code that a module is being loaded. */
401 error = elf_cpu_load_file(lf);
402 if (error != 0)
403 return (error);
404
405 #ifdef GDB
406 GDB_STATE(RT_ADD);
407 ef->gdb.l_addr = lf->address;
408 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
409 strcpy(newfilename, lf->filename);
410 ef->gdb.l_name = newfilename;
411 ef->gdb.l_ld = ef->dynamic;
412 link_elf_add_gdb(&ef->gdb);
413 GDB_STATE(RT_CONSISTENT);
414 #endif
415
416 /* Invoke .ctors */
417 link_elf_invoke_ctors(lf);
418 return (0);
419 }
420
421 #ifdef RELOCATABLE_KERNEL
422 /*
423 * __startkernel and __endkernel are symbols set up as relocation canaries.
424 *
425 * They are defined in locore to reference linker script symbols at the
426 * beginning and end of the LOAD area. This has the desired side effect of
427 * giving us variables that have relative relocations pointing at them, so
428 * relocation of the kernel object will cause the variables to be updated
429 * automatically by the runtime linker when we initialize.
430 *
431 * There are two main reasons to relocate the kernel:
432 * 1) If the loader needed to load the kernel at an alternate load address.
433 * 2) If the kernel is switching address spaces on machines like POWER9
434 * under Radix where the high bits of the effective address are used to
435 * differentiate between hypervisor, host, guest, and problem state.
436 */
437 extern vm_offset_t __startkernel, __endkernel;
438 #endif
439
440 static unsigned long kern_relbase = KERNBASE;
441
442 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
443 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
444 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
445 &kern_relbase, 0, "Kernel relocated base address");
446
447 static void
link_elf_init(void * arg)448 link_elf_init(void* arg)
449 {
450 Elf_Dyn *dp;
451 Elf_Addr *ctors_addrp;
452 Elf_Size *ctors_sizep;
453 caddr_t baseptr, sizeptr;
454 elf_file_t ef;
455 const char *modname;
456
457 linker_add_class(&link_elf_class);
458
459 dp = (Elf_Dyn *)&_DYNAMIC;
460 modname = (char *)preload_search_info(preload_kmdp, MODINFO_NAME);
461 if (modname == NULL)
462 modname = "kernel";
463 linker_kernel_file = linker_make_file(modname, &link_elf_class);
464 if (linker_kernel_file == NULL)
465 panic("%s: Can't create linker structures for kernel",
466 __func__);
467
468 ef = (elf_file_t) linker_kernel_file;
469 ef->preloaded = 1;
470 #ifdef RELOCATABLE_KERNEL
471 /* Compute relative displacement */
472 ef->address = (caddr_t) (__startkernel - KERNBASE);
473 #else
474 ef->address = 0;
475 #endif
476 #ifdef SPARSE_MAPPING
477 ef->object = NULL;
478 #endif
479 ef->dynamic = dp;
480
481 if (dp != NULL)
482 parse_dynamic(ef);
483 #ifdef RELOCATABLE_KERNEL
484 linker_kernel_file->address = (caddr_t)__startkernel;
485 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
486 kern_relbase = (unsigned long)__startkernel;
487 #else
488 linker_kernel_file->address += KERNBASE;
489 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
490 #endif
491
492 if (preload_kmdp != NULL) {
493 ef->modptr = preload_kmdp;
494 baseptr = preload_search_info(preload_kmdp, MODINFO_ADDR);
495 if (baseptr != NULL)
496 linker_kernel_file->address = *(caddr_t *)baseptr;
497 sizeptr = preload_search_info(preload_kmdp, MODINFO_SIZE);
498 if (sizeptr != NULL)
499 linker_kernel_file->size = *(size_t *)sizeptr;
500 ctors_addrp = (Elf_Addr *)preload_search_info(preload_kmdp,
501 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
502 ctors_sizep = (Elf_Size *)preload_search_info(preload_kmdp,
503 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
504 if (ctors_addrp != NULL && ctors_sizep != NULL) {
505 linker_kernel_file->ctors_addr = ef->address +
506 *ctors_addrp;
507 linker_kernel_file->ctors_size = *ctors_sizep;
508 }
509 }
510 (void)link_elf_preload_parse_symbols(ef);
511
512 #ifdef GDB
513 r_debug.r_map = NULL;
514 r_debug.r_brk = r_debug_state;
515 r_debug.r_state = RT_CONSISTENT;
516 #endif
517
518 (void)link_elf_link_common_finish(linker_kernel_file);
519 linker_kernel_file->flags |= LINKER_FILE_LINKED;
520 TAILQ_INIT(&set_pcpu_list);
521 ef->pcpu_start = DPCPU_START;
522 ef->pcpu_stop = DPCPU_STOP;
523 ef->pcpu_base = DPCPU_START;
524 #ifdef VIMAGE
525 TAILQ_INIT(&set_vnet_list);
526 vnet_save_init((void *)VNET_START, VNET_STOP - VNET_START);
527 ef->vnet_start = VNET_START;
528 ef->vnet_stop = VNET_STOP;
529 ef->vnet_base = VNET_START;
530 #endif
531 }
532
533 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
534
535 static int
link_elf_preload_parse_symbols(elf_file_t ef)536 link_elf_preload_parse_symbols(elf_file_t ef)
537 {
538 caddr_t pointer;
539 caddr_t ssym, esym, base;
540 caddr_t strtab;
541 int strcnt;
542 Elf_Sym *symtab;
543 int symcnt;
544
545 if (ef->modptr == NULL)
546 return (0);
547 pointer = preload_search_info(ef->modptr,
548 MODINFO_METADATA | MODINFOMD_SSYM);
549 if (pointer == NULL)
550 return (0);
551 ssym = *(caddr_t *)pointer;
552 pointer = preload_search_info(ef->modptr,
553 MODINFO_METADATA | MODINFOMD_ESYM);
554 if (pointer == NULL)
555 return (0);
556 esym = *(caddr_t *)pointer;
557
558 base = ssym;
559
560 symcnt = *(long *)base;
561 base += sizeof(long);
562 symtab = (Elf_Sym *)base;
563 base += roundup(symcnt, sizeof(long));
564
565 if (base > esym || base < ssym) {
566 printf("Symbols are corrupt!\n");
567 return (EINVAL);
568 }
569
570 strcnt = *(long *)base;
571 base += sizeof(long);
572 strtab = base;
573 base += roundup(strcnt, sizeof(long));
574
575 if (base > esym || base < ssym) {
576 printf("Symbols are corrupt!\n");
577 return (EINVAL);
578 }
579
580 ef->ddbsymtab = symtab;
581 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
582 ef->ddbstrtab = strtab;
583 ef->ddbstrcnt = strcnt;
584
585 return (0);
586 }
587
588 static int
parse_dynamic(elf_file_t ef)589 parse_dynamic(elf_file_t ef)
590 {
591 Elf_Dyn *dp;
592 int plttype = DT_REL;
593
594 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
595 switch (dp->d_tag) {
596 case DT_HASH:
597 {
598 /* From src/libexec/rtld-elf/rtld.c */
599 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
600 (ef->address + dp->d_un.d_ptr);
601 ef->nbuckets = hashtab[0];
602 ef->nchains = hashtab[1];
603 ef->buckets = hashtab + 2;
604 ef->chains = ef->buckets + ef->nbuckets;
605 break;
606 }
607 case DT_STRTAB:
608 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
609 break;
610 case DT_STRSZ:
611 ef->strsz = dp->d_un.d_val;
612 break;
613 case DT_SYMTAB:
614 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
615 break;
616 case DT_SYMENT:
617 if (dp->d_un.d_val != sizeof(Elf_Sym))
618 return (ENOEXEC);
619 break;
620 case DT_PLTGOT:
621 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
622 break;
623 case DT_REL:
624 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
625 break;
626 case DT_RELSZ:
627 ef->relsize = dp->d_un.d_val;
628 break;
629 case DT_RELENT:
630 if (dp->d_un.d_val != sizeof(Elf_Rel))
631 return (ENOEXEC);
632 break;
633 case DT_JMPREL:
634 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
635 break;
636 case DT_PLTRELSZ:
637 ef->pltrelsize = dp->d_un.d_val;
638 break;
639 case DT_RELA:
640 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
641 break;
642 case DT_RELASZ:
643 ef->relasize = dp->d_un.d_val;
644 break;
645 case DT_RELAENT:
646 if (dp->d_un.d_val != sizeof(Elf_Rela))
647 return (ENOEXEC);
648 break;
649 case DT_PLTREL:
650 plttype = dp->d_un.d_val;
651 if (plttype != DT_REL && plttype != DT_RELA)
652 return (ENOEXEC);
653 break;
654 #ifdef GDB
655 case DT_DEBUG:
656 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
657 break;
658 #endif
659 }
660 }
661
662 if (plttype == DT_RELA) {
663 ef->pltrela = (const Elf_Rela *)ef->pltrel;
664 ef->pltrel = NULL;
665 ef->pltrelasize = ef->pltrelsize;
666 ef->pltrelsize = 0;
667 }
668
669 ef->ddbsymtab = ef->symtab;
670 ef->ddbsymcnt = ef->nchains;
671 ef->ddbstrtab = ef->strtab;
672 ef->ddbstrcnt = ef->strsz;
673
674 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
675 }
676
677 #define LS_PADDING 0x90909090
678 static int
parse_dpcpu(elf_file_t ef)679 parse_dpcpu(elf_file_t ef)
680 {
681 int error, size;
682 #if defined(__i386__)
683 uint32_t pad;
684 #endif
685
686 ef->pcpu_start = 0;
687 ef->pcpu_stop = 0;
688 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
689 (void ***)&ef->pcpu_stop, NULL);
690 /* Error just means there is no pcpu set to relocate. */
691 if (error != 0)
692 return (0);
693 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
694 /* Empty set? */
695 if (size < 1)
696 return (0);
697 #if defined(__i386__)
698 /* In case we do find __start/stop_set_ symbols double-check. */
699 if (size < 4) {
700 uprintf("Kernel module '%s' must be recompiled with "
701 "linker script\n", ef->lf.pathname);
702 return (ENOEXEC);
703 }
704
705 /* Padding from linker-script correct? */
706 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
707 if (pad != LS_PADDING) {
708 uprintf("Kernel module '%s' must be recompiled with "
709 "linker script, invalid padding %#04x (%#04x)\n",
710 ef->lf.pathname, pad, LS_PADDING);
711 return (ENOEXEC);
712 }
713 /* If we only have valid padding, nothing to do. */
714 if (size == 4)
715 return (0);
716 #endif
717 /*
718 * Allocate space in the primary pcpu area. Copy in our
719 * initialization from the data section and then initialize
720 * all per-cpu storage from that.
721 */
722 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
723 if (ef->pcpu_base == 0) {
724 printf("%s: pcpu module space is out of space; "
725 "cannot allocate %d for %s\n",
726 __func__, size, ef->lf.pathname);
727 return (ENOSPC);
728 }
729 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
730 dpcpu_copy((void *)ef->pcpu_base, size);
731 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
732 ef->pcpu_base);
733
734 return (0);
735 }
736
737 #ifdef VIMAGE
738 static int
parse_vnet(elf_file_t ef)739 parse_vnet(elf_file_t ef)
740 {
741 int error, size;
742 #if defined(__i386__)
743 uint32_t pad;
744 #endif
745
746 ef->vnet_start = 0;
747 ef->vnet_stop = 0;
748 ef->vnet_base = 0;
749 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
750 (void ***)&ef->vnet_stop, NULL);
751 /* Error just means there is no vnet data set to relocate. */
752 if (error != 0)
753 return (0);
754 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
755 /* Empty set? */
756 if (size < 1)
757 return (0);
758 #if defined(__i386__)
759 /* In case we do find __start/stop_set_ symbols double-check. */
760 if (size < 4) {
761 uprintf("Kernel module '%s' must be recompiled with "
762 "linker script\n", ef->lf.pathname);
763 return (ENOEXEC);
764 }
765
766 /* Padding from linker-script correct? */
767 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
768 if (pad != LS_PADDING) {
769 uprintf("Kernel module '%s' must be recompiled with "
770 "linker script, invalid padding %#04x (%#04x)\n",
771 ef->lf.pathname, pad, LS_PADDING);
772 return (ENOEXEC);
773 }
774 /* If we only have valid padding, nothing to do. */
775 if (size == 4)
776 return (0);
777 #endif
778 /*
779 * Allocate space in the primary vnet area. Copy in our
780 * initialization from the data section and then initialize
781 * all per-vnet storage from that.
782 */
783 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
784 if (ef->vnet_base == 0) {
785 printf("%s: vnet module space is out of space; "
786 "cannot allocate %d for %s\n",
787 __func__, size, ef->lf.pathname);
788 return (ENOSPC);
789 }
790 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
791 vnet_save_init((void *)ef->vnet_base, size);
792 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
793 ef->vnet_base);
794
795 return (0);
796 }
797 #endif
798 #undef LS_PADDING
799
800 /*
801 * Apply the specified protection to the loadable segments of a preloaded linker
802 * file.
803 */
804 static int
preload_protect(elf_file_t ef,vm_prot_t prot)805 preload_protect(elf_file_t ef, vm_prot_t prot)
806 {
807 #if defined(__aarch64__) || defined(__amd64__)
808 Elf_Ehdr *hdr;
809 Elf_Phdr *phdr, *phlimit;
810 vm_prot_t nprot;
811 int error;
812
813 error = 0;
814 hdr = (Elf_Ehdr *)ef->address;
815 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
816 phlimit = phdr + hdr->e_phnum;
817 for (; phdr < phlimit; phdr++) {
818 if (phdr->p_type != PT_LOAD)
819 continue;
820
821 nprot = prot | VM_PROT_READ;
822 if ((phdr->p_flags & PF_W) != 0)
823 nprot |= VM_PROT_WRITE;
824 if ((phdr->p_flags & PF_X) != 0)
825 nprot |= VM_PROT_EXECUTE;
826 error = pmap_change_prot((vm_offset_t)ef->address +
827 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
828 if (error != 0)
829 break;
830 }
831 return (error);
832 #else
833 return (0);
834 #endif
835 }
836
837 #ifdef __arm__
838 /*
839 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
840 * searching for the section header that describes it. There may be no unwind
841 * info, for example in a module containing only data.
842 */
843 static void
link_elf_locate_exidx(linker_file_t lf,Elf_Shdr * shdr,int nhdr)844 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
845 {
846 int i;
847
848 for (i = 0; i < nhdr; i++) {
849 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
850 lf->exidx_addr = shdr[i].sh_addr + lf->address;
851 lf->exidx_size = shdr[i].sh_size;
852 break;
853 }
854 }
855 }
856
857 /*
858 * Locate the section headers metadata in a preloaded module, then use it to
859 * locate the exception/unwind table in the module. The size of the metadata
860 * block is stored in a uint32 word immediately before the data itself, and a
861 * comment in preload_search_info() says it is safe to rely on that.
862 */
863 static void
link_elf_locate_exidx_preload(struct linker_file * lf,caddr_t modptr)864 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
865 {
866 uint32_t *modinfo;
867 Elf_Shdr *shdr;
868 uint32_t nhdr;
869
870 modinfo = (uint32_t *)preload_search_info(modptr,
871 MODINFO_METADATA | MODINFOMD_SHDR);
872 if (modinfo != NULL) {
873 shdr = (Elf_Shdr *)modinfo;
874 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
875 link_elf_locate_exidx(lf, shdr, nhdr);
876 }
877 }
878
879 #endif /* __arm__ */
880
881 static int
link_elf_link_preload(linker_class_t cls,const char * filename,linker_file_t * result)882 link_elf_link_preload(linker_class_t cls, const char *filename,
883 linker_file_t *result)
884 {
885 Elf_Addr *ctors_addrp;
886 Elf_Size *ctors_sizep;
887 caddr_t modptr, baseptr, sizeptr, dynptr;
888 char *type;
889 elf_file_t ef;
890 linker_file_t lf;
891 int error;
892 vm_offset_t dp;
893
894 /* Look to see if we have the file preloaded */
895 modptr = preload_search_by_name(filename);
896 if (modptr == NULL)
897 return (ENOENT);
898
899 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
900 baseptr = preload_search_info(modptr, MODINFO_ADDR);
901 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
902 dynptr = preload_search_info(modptr,
903 MODINFO_METADATA | MODINFOMD_DYNAMIC);
904 if (type == NULL || strcmp(type, preload_modtype) != 0)
905 return (EFTYPE);
906 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
907 return (EINVAL);
908
909 lf = linker_make_file(filename, &link_elf_class);
910 if (lf == NULL)
911 return (ENOMEM);
912
913 ef = (elf_file_t) lf;
914 ef->preloaded = 1;
915 ef->modptr = modptr;
916 ef->address = *(caddr_t *)baseptr;
917 #ifdef SPARSE_MAPPING
918 ef->object = NULL;
919 #endif
920 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
921 ef->dynamic = (Elf_Dyn *)dp;
922 lf->address = ef->address;
923 lf->size = *(size_t *)sizeptr;
924
925 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
926 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
927 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
928 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
929 if (ctors_addrp != NULL && ctors_sizep != NULL) {
930 lf->ctors_addr = ef->address + *ctors_addrp;
931 lf->ctors_size = *ctors_sizep;
932 }
933
934 #ifdef __arm__
935 link_elf_locate_exidx_preload(lf, modptr);
936 #endif
937
938 error = parse_dynamic(ef);
939 if (error == 0)
940 error = parse_dpcpu(ef);
941 #ifdef VIMAGE
942 if (error == 0)
943 error = parse_vnet(ef);
944 #endif
945 if (error == 0)
946 error = preload_protect(ef, VM_PROT_ALL);
947 if (error != 0) {
948 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
949 return (error);
950 }
951 link_elf_reloc_local(lf);
952 *result = lf;
953 return (0);
954 }
955
956 static int
link_elf_link_preload_finish(linker_file_t lf)957 link_elf_link_preload_finish(linker_file_t lf)
958 {
959 elf_file_t ef;
960 int error;
961
962 ef = (elf_file_t) lf;
963 error = relocate_file(ef);
964 if (error == 0)
965 error = preload_protect(ef, VM_PROT_NONE);
966 if (error != 0)
967 return (error);
968 (void)link_elf_preload_parse_symbols(ef);
969
970 return (link_elf_link_common_finish(lf));
971 }
972
973 static int
link_elf_load_file(linker_class_t cls,const char * filename,linker_file_t * result)974 link_elf_load_file(linker_class_t cls, const char* filename,
975 linker_file_t* result)
976 {
977 struct nameidata nd;
978 struct thread* td = curthread; /* XXX */
979 Elf_Ehdr *hdr;
980 caddr_t firstpage, segbase;
981 int nbytes, i;
982 Elf_Phdr *phdr;
983 Elf_Phdr *phlimit;
984 Elf_Phdr *segs[MAXSEGS];
985 int nsegs;
986 Elf_Phdr *phdyn;
987 caddr_t mapbase;
988 size_t mapsize;
989 Elf_Addr base_vaddr;
990 Elf_Addr base_vlimit;
991 int error = 0;
992 ssize_t resid;
993 int flags;
994 elf_file_t ef;
995 linker_file_t lf;
996 Elf_Shdr *shdr;
997 int symtabindex;
998 int symstrindex;
999 int shstrindex;
1000 int symcnt;
1001 int strcnt;
1002 char *shstrs;
1003
1004 shdr = NULL;
1005 lf = NULL;
1006 shstrs = NULL;
1007
1008 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
1009 flags = FREAD;
1010 error = vn_open(&nd, &flags, 0, NULL);
1011 if (error != 0)
1012 return (error);
1013 NDFREE_PNBUF(&nd);
1014 if (nd.ni_vp->v_type != VREG) {
1015 error = ENOEXEC;
1016 firstpage = NULL;
1017 goto out;
1018 }
1019 #ifdef MAC
1020 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1021 if (error != 0) {
1022 firstpage = NULL;
1023 goto out;
1024 }
1025 #endif
1026
1027 /*
1028 * Read the elf header from the file.
1029 */
1030 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1031 hdr = (Elf_Ehdr *)firstpage;
1032 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1033 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1034 &resid, td);
1035 nbytes = PAGE_SIZE - resid;
1036 if (error != 0)
1037 goto out;
1038
1039 if (!IS_ELF(*hdr)) {
1040 error = ENOEXEC;
1041 goto out;
1042 }
1043
1044 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1045 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1046 link_elf_error(filename, "Unsupported file layout");
1047 error = ENOEXEC;
1048 goto out;
1049 }
1050 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1051 hdr->e_version != EV_CURRENT) {
1052 link_elf_error(filename, "Unsupported file version");
1053 error = ENOEXEC;
1054 goto out;
1055 }
1056 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1057 error = ENOSYS;
1058 goto out;
1059 }
1060 if (hdr->e_machine != ELF_TARG_MACH) {
1061 link_elf_error(filename, "Unsupported machine");
1062 error = ENOEXEC;
1063 goto out;
1064 }
1065
1066 /*
1067 * We rely on the program header being in the first page.
1068 * This is not strictly required by the ABI specification, but
1069 * it seems to always true in practice. And, it simplifies
1070 * things considerably.
1071 */
1072 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1073 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1074 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1075 link_elf_error(filename, "Unreadable program headers");
1076
1077 /*
1078 * Scan the program header entries, and save key information.
1079 *
1080 * We rely on there being exactly two load segments, text and data,
1081 * in that order.
1082 */
1083 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1084 phlimit = phdr + hdr->e_phnum;
1085 nsegs = 0;
1086 phdyn = NULL;
1087 while (phdr < phlimit) {
1088 switch (phdr->p_type) {
1089 case PT_LOAD:
1090 if (nsegs == MAXSEGS) {
1091 link_elf_error(filename, "Too many sections");
1092 error = ENOEXEC;
1093 goto out;
1094 }
1095 /*
1096 * XXX: We just trust they come in right order ??
1097 */
1098 segs[nsegs] = phdr;
1099 ++nsegs;
1100 break;
1101
1102 case PT_DYNAMIC:
1103 phdyn = phdr;
1104 break;
1105
1106 case PT_INTERP:
1107 error = ENOSYS;
1108 goto out;
1109 }
1110
1111 ++phdr;
1112 }
1113 if (phdyn == NULL) {
1114 link_elf_error(filename, "Object is not dynamically-linked");
1115 error = ENOEXEC;
1116 goto out;
1117 }
1118 if (nsegs == 0) {
1119 link_elf_error(filename, "No sections");
1120 error = ENOEXEC;
1121 goto out;
1122 }
1123
1124 /*
1125 * Allocate the entire address space of the object, to stake
1126 * out our contiguous region, and to establish the base
1127 * address for relocation.
1128 */
1129 base_vaddr = trunc_page(segs[0]->p_vaddr);
1130 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1131 segs[nsegs - 1]->p_memsz);
1132 mapsize = base_vlimit - base_vaddr;
1133
1134 lf = linker_make_file(filename, &link_elf_class);
1135 if (lf == NULL) {
1136 error = ENOMEM;
1137 goto out;
1138 }
1139
1140 ef = (elf_file_t) lf;
1141 #ifdef SPARSE_MAPPING
1142 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1143 0, thread0.td_ucred);
1144 if (ef->object == NULL) {
1145 error = ENOMEM;
1146 goto out;
1147 }
1148 #ifdef __amd64__
1149 mapbase = (caddr_t)KERNBASE;
1150 #else
1151 mapbase = (caddr_t)vm_map_min(kernel_map);
1152 #endif
1153 /*
1154 * Mapping protections are downgraded after relocation processing.
1155 */
1156 error = vm_map_find(kernel_map, ef->object, 0,
1157 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1158 VM_PROT_ALL, VM_PROT_ALL, 0);
1159 if (error != 0) {
1160 vm_object_deallocate(ef->object);
1161 ef->object = NULL;
1162 goto out;
1163 }
1164 #else
1165 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1166 #endif
1167 ef->address = mapbase;
1168
1169 /*
1170 * Read the text and data sections and zero the bss.
1171 */
1172 for (i = 0; i < nsegs; i++) {
1173 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1174
1175 #ifdef SPARSE_MAPPING
1176 /*
1177 * Consecutive segments may have different mapping permissions,
1178 * so be strict and verify that their mappings do not overlap.
1179 */
1180 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1181 error = EINVAL;
1182 goto out;
1183 }
1184
1185 error = vm_map_wire(kernel_map,
1186 (vm_offset_t)segbase,
1187 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1188 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1189 if (error != KERN_SUCCESS) {
1190 error = ENOMEM;
1191 goto out;
1192 }
1193 #endif
1194
1195 error = vn_rdwr(UIO_READ, nd.ni_vp,
1196 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1197 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1198 &resid, td);
1199 if (error != 0)
1200 goto out;
1201 bzero(segbase + segs[i]->p_filesz,
1202 segs[i]->p_memsz - segs[i]->p_filesz);
1203 }
1204
1205 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1206
1207 lf->address = ef->address;
1208 lf->size = mapsize;
1209
1210 error = parse_dynamic(ef);
1211 if (error != 0)
1212 goto out;
1213 error = parse_dpcpu(ef);
1214 if (error != 0)
1215 goto out;
1216 #ifdef VIMAGE
1217 error = parse_vnet(ef);
1218 if (error != 0)
1219 goto out;
1220 #endif
1221 link_elf_reloc_local(lf);
1222
1223 VOP_UNLOCK(nd.ni_vp);
1224 error = linker_load_dependencies(lf);
1225 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1226 if (error != 0)
1227 goto out;
1228 error = relocate_file(ef);
1229 if (error != 0)
1230 goto out;
1231
1232 #ifdef SPARSE_MAPPING
1233 /*
1234 * Downgrade permissions on text segment mappings now that relocation
1235 * processing is complete. Restrict permissions on read-only segments.
1236 */
1237 for (i = 0; i < nsegs; i++) {
1238 vm_prot_t prot;
1239
1240 if (segs[i]->p_type != PT_LOAD)
1241 continue;
1242
1243 prot = VM_PROT_READ;
1244 if ((segs[i]->p_flags & PF_W) != 0)
1245 prot |= VM_PROT_WRITE;
1246 if ((segs[i]->p_flags & PF_X) != 0)
1247 prot |= VM_PROT_EXECUTE;
1248 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1249 error = vm_map_protect(kernel_map,
1250 (vm_offset_t)segbase,
1251 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1252 prot, 0, VM_MAP_PROTECT_SET_PROT);
1253 if (error != KERN_SUCCESS) {
1254 error = ENOMEM;
1255 goto out;
1256 }
1257 }
1258 #endif
1259
1260 /*
1261 * Try and load the symbol table if it's present. (you can
1262 * strip it!)
1263 */
1264 nbytes = hdr->e_shnum * hdr->e_shentsize;
1265 if (nbytes == 0 || hdr->e_shoff == 0)
1266 goto nosyms;
1267 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1268 error = vn_rdwr(UIO_READ, nd.ni_vp,
1269 (caddr_t)shdr, nbytes, hdr->e_shoff,
1270 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1271 &resid, td);
1272 if (error != 0)
1273 goto out;
1274
1275 /* Read section string table */
1276 shstrindex = hdr->e_shstrndx;
1277 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1278 shdr[shstrindex].sh_size != 0) {
1279 nbytes = shdr[shstrindex].sh_size;
1280 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1281 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1282 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1283 td->td_ucred, NOCRED, &resid, td);
1284 if (error)
1285 goto out;
1286 }
1287
1288 symtabindex = -1;
1289 symstrindex = -1;
1290 for (i = 0; i < hdr->e_shnum; i++) {
1291 if (shdr[i].sh_type == SHT_SYMTAB) {
1292 symtabindex = i;
1293 symstrindex = shdr[i].sh_link;
1294 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1295 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1296 /* Record relocated address and size of .ctors. */
1297 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1298 lf->ctors_size = shdr[i].sh_size;
1299 }
1300 }
1301 if (symtabindex < 0 || symstrindex < 0)
1302 goto nosyms;
1303
1304 symcnt = shdr[symtabindex].sh_size;
1305 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1306 strcnt = shdr[symstrindex].sh_size;
1307 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1308
1309 error = vn_rdwr(UIO_READ, nd.ni_vp,
1310 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1311 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1312 &resid, td);
1313 if (error != 0)
1314 goto out;
1315 error = vn_rdwr(UIO_READ, nd.ni_vp,
1316 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1317 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1318 &resid, td);
1319 if (error != 0)
1320 goto out;
1321
1322 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1323 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1324 ef->ddbstrcnt = strcnt;
1325 ef->ddbstrtab = ef->strbase;
1326
1327 nosyms:
1328
1329 #ifdef __arm__
1330 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1331 #endif
1332
1333 error = link_elf_link_common_finish(lf);
1334 if (error != 0)
1335 goto out;
1336
1337 *result = lf;
1338
1339 out:
1340 VOP_UNLOCK(nd.ni_vp);
1341 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1342 if (error != 0 && lf != NULL)
1343 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1344 free(shdr, M_LINKER);
1345 free(firstpage, M_LINKER);
1346 free(shstrs, M_LINKER);
1347
1348 return (error);
1349 }
1350
1351 Elf_Addr
elf_relocaddr(linker_file_t lf,Elf_Addr x)1352 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1353 {
1354 elf_file_t ef;
1355
1356 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1357 ("elf_relocaddr: unexpected linker file %p", lf));
1358
1359 ef = (elf_file_t)lf;
1360 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1361 return ((x - ef->pcpu_start) + ef->pcpu_base);
1362 #ifdef VIMAGE
1363 if (x >= ef->vnet_start && x < ef->vnet_stop)
1364 return ((x - ef->vnet_start) + ef->vnet_base);
1365 #endif
1366 return (x);
1367 }
1368
1369 static void
link_elf_unload_file(linker_file_t file)1370 link_elf_unload_file(linker_file_t file)
1371 {
1372 elf_file_t ef = (elf_file_t) file;
1373
1374 if (ef->pcpu_base != 0) {
1375 dpcpu_free((void *)ef->pcpu_base,
1376 ef->pcpu_stop - ef->pcpu_start);
1377 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1378 }
1379 #ifdef VIMAGE
1380 if (ef->vnet_base != 0) {
1381 vnet_data_free((void *)ef->vnet_base,
1382 ef->vnet_stop - ef->vnet_start);
1383 elf_set_delete(&set_vnet_list, ef->vnet_start);
1384 }
1385 #endif
1386 #ifdef GDB
1387 if (ef->gdb.l_ld != NULL) {
1388 GDB_STATE(RT_DELETE);
1389 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1390 link_elf_delete_gdb(&ef->gdb);
1391 GDB_STATE(RT_CONSISTENT);
1392 }
1393 #endif
1394
1395 /* Notify MD code that a module is being unloaded. */
1396 elf_cpu_unload_file(file);
1397
1398 if (ef->preloaded) {
1399 link_elf_unload_preload(file);
1400 return;
1401 }
1402
1403 #ifdef SPARSE_MAPPING
1404 if (ef->object != NULL) {
1405 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1406 (vm_offset_t) ef->address
1407 + (ef->object->size << PAGE_SHIFT));
1408 }
1409 #else
1410 free(ef->address, M_LINKER);
1411 #endif
1412 free(ef->symbase, M_LINKER);
1413 free(ef->strbase, M_LINKER);
1414 free(ef->ctftab, M_LINKER);
1415 free(ef->ctfoff, M_LINKER);
1416 free(ef->typoff, M_LINKER);
1417 }
1418
1419 static void
link_elf_unload_preload(linker_file_t file)1420 link_elf_unload_preload(linker_file_t file)
1421 {
1422
1423 if (file->pathname != NULL)
1424 preload_delete_name(file->pathname);
1425 }
1426
1427 static const char *
symbol_name(elf_file_t ef,Elf_Size r_info)1428 symbol_name(elf_file_t ef, Elf_Size r_info)
1429 {
1430 const Elf_Sym *ref;
1431
1432 if (ELF_R_SYM(r_info)) {
1433 ref = ef->symtab + ELF_R_SYM(r_info);
1434 return (ef->strtab + ref->st_name);
1435 }
1436 return (NULL);
1437 }
1438
1439 static int
symbol_type(elf_file_t ef,Elf_Size r_info)1440 symbol_type(elf_file_t ef, Elf_Size r_info)
1441 {
1442 const Elf_Sym *ref;
1443
1444 if (ELF_R_SYM(r_info)) {
1445 ref = ef->symtab + ELF_R_SYM(r_info);
1446 return (ELF_ST_TYPE(ref->st_info));
1447 }
1448 return (STT_NOTYPE);
1449 }
1450
1451 static int
relocate_file1(elf_file_t ef,elf_lookup_fn lookup,elf_reloc_fn reloc,bool ifuncs)1452 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1453 bool ifuncs)
1454 {
1455 const Elf_Rel *rel;
1456 const Elf_Rela *rela;
1457 const char *symname;
1458
1459 TSENTER();
1460 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1461 for ((iter) = (tbl); (iter) != NULL && \
1462 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1463 if ((symbol_type(ef, (iter)->r_info) == \
1464 STT_GNU_IFUNC || \
1465 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1466 continue; \
1467 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1468 (iter), (type), lookup)) { \
1469 symname = symbol_name(ef, (iter)->r_info); \
1470 printf("link_elf: symbol %s undefined\n", \
1471 symname); \
1472 return (ENOENT); \
1473 } \
1474 } \
1475 } while (0)
1476
1477 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1478 TSENTER2("ef->rela");
1479 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1480 TSEXIT2("ef->rela");
1481 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1482 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1483
1484 #undef APPLY_RELOCS
1485
1486 TSEXIT();
1487 return (0);
1488 }
1489
1490 static int
relocate_file(elf_file_t ef)1491 relocate_file(elf_file_t ef)
1492 {
1493 int error;
1494
1495 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1496 if (error == 0)
1497 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1498 return (error);
1499 }
1500
1501 /*
1502 * SysV hash function for symbol table lookup. It is specified by the
1503 * System V ABI.
1504 */
1505 static Elf32_Word
elf_hash(const char * name)1506 elf_hash(const char *name)
1507 {
1508 const unsigned char *p = (const unsigned char *)name;
1509 Elf32_Word h = 0;
1510
1511 while (*p != '\0') {
1512 h = (h << 4) + *p++;
1513 h ^= (h >> 24) & 0xf0;
1514 }
1515 return (h & 0x0fffffff);
1516 }
1517
1518 static int
link_elf_lookup_symbol1(linker_file_t lf,const char * name,c_linker_sym_t * sym,bool see_local)1519 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1520 bool see_local)
1521 {
1522 elf_file_t ef = (elf_file_t) lf;
1523 unsigned long symnum;
1524 const Elf_Sym* symp;
1525 const char *strp;
1526 Elf32_Word hash;
1527
1528 /* If we don't have a hash, bail. */
1529 if (ef->buckets == NULL || ef->nbuckets == 0) {
1530 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1531 return (ENOENT);
1532 }
1533
1534 /* First, search hashed global symbols */
1535 hash = elf_hash(name);
1536 symnum = ef->buckets[hash % ef->nbuckets];
1537
1538 while (symnum != STN_UNDEF) {
1539 if (symnum >= ef->nchains) {
1540 printf("%s: corrupt symbol table\n", __func__);
1541 return (ENOENT);
1542 }
1543
1544 symp = ef->symtab + symnum;
1545 if (symp->st_name == 0) {
1546 printf("%s: corrupt symbol table\n", __func__);
1547 return (ENOENT);
1548 }
1549
1550 strp = ef->strtab + symp->st_name;
1551
1552 if (strcmp(name, strp) == 0) {
1553 if (symp->st_shndx != SHN_UNDEF ||
1554 (symp->st_value != 0 &&
1555 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1556 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1557 if (see_local ||
1558 ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1559 *sym = (c_linker_sym_t) symp;
1560 return (0);
1561 }
1562 }
1563 return (ENOENT);
1564 }
1565
1566 symnum = ef->chains[symnum];
1567 }
1568
1569 return (ENOENT);
1570 }
1571
1572 static int
link_elf_lookup_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1573 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1574 {
1575 if (link_elf_leak_locals)
1576 return (link_elf_lookup_debug_symbol(lf, name, sym));
1577 return (link_elf_lookup_symbol1(lf, name, sym, false));
1578 }
1579
1580 static int
link_elf_lookup_debug_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1581 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1582 c_linker_sym_t *sym)
1583 {
1584 elf_file_t ef = (elf_file_t)lf;
1585 const Elf_Sym* symp;
1586 const char *strp;
1587 int i;
1588
1589 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1590 return (0);
1591
1592 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1593 strp = ef->ddbstrtab + symp->st_name;
1594 if (strcmp(name, strp) == 0) {
1595 if (symp->st_shndx != SHN_UNDEF ||
1596 (symp->st_value != 0 &&
1597 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1598 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1599 *sym = (c_linker_sym_t) symp;
1600 return (0);
1601 }
1602 return (ENOENT);
1603 }
1604 }
1605
1606 return (ENOENT);
1607 }
1608
1609 static int
link_elf_lookup_debug_symbol_ctf(linker_file_t lf,const char * name,c_linker_sym_t * sym,linker_ctf_t * lc)1610 link_elf_lookup_debug_symbol_ctf(linker_file_t lf, const char *name,
1611 c_linker_sym_t *sym, linker_ctf_t *lc)
1612 {
1613 elf_file_t ef = (elf_file_t)lf;
1614 const Elf_Sym *symp;
1615 const char *strp;
1616 int i;
1617
1618 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1619 strp = ef->ddbstrtab + symp->st_name;
1620 if (strcmp(name, strp) == 0) {
1621 if (symp->st_shndx != SHN_UNDEF ||
1622 (symp->st_value != 0 &&
1623 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1624 ELF_ST_TYPE(symp->st_info) ==
1625 STT_GNU_IFUNC))) {
1626 *sym = (c_linker_sym_t)symp;
1627 break;
1628 }
1629 return (ENOENT);
1630 }
1631 }
1632
1633 /* Populate CTF info structure if symbol was found. */
1634 return (i < ef->ddbsymcnt ? link_elf_ctf_get_ddb(lf, lc) : ENOENT);
1635 }
1636
1637 static void
link_elf_ifunc_symbol_value(linker_file_t lf,caddr_t * valp,size_t * sizep)1638 link_elf_ifunc_symbol_value(linker_file_t lf, caddr_t *valp, size_t *sizep)
1639 {
1640 c_linker_sym_t sym;
1641 elf_file_t ef;
1642 const Elf_Sym *es;
1643 caddr_t val;
1644 long off;
1645
1646 val = *valp;
1647 ef = (elf_file_t)lf;
1648
1649 /* Provide the value and size of the target symbol, if available. */
1650 val = ((caddr_t (*)(void))val)();
1651 if (link_elf_search_symbol(lf, val, &sym, &off) == 0 && off == 0) {
1652 es = (const Elf_Sym *)sym;
1653 *valp = (caddr_t)ef->address + es->st_value;
1654 *sizep = es->st_size;
1655 } else {
1656 *valp = val;
1657 *sizep = 0;
1658 }
1659 }
1660
1661 static int
link_elf_symbol_values1(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval,bool see_local)1662 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1663 linker_symval_t *symval, bool see_local)
1664 {
1665 elf_file_t ef;
1666 const Elf_Sym *es;
1667 caddr_t val;
1668 size_t size;
1669
1670 ef = (elf_file_t)lf;
1671 es = (const Elf_Sym *)sym;
1672 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1673 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1674 return (ENOENT);
1675 symval->name = ef->strtab + es->st_name;
1676 val = (caddr_t)ef->address + es->st_value;
1677 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1678 link_elf_ifunc_symbol_value(lf, &val, &size);
1679 else
1680 size = es->st_size;
1681 symval->value = val;
1682 symval->size = size;
1683 return (0);
1684 }
1685 return (ENOENT);
1686 }
1687
1688 static int
link_elf_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1689 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1690 linker_symval_t *symval)
1691 {
1692 if (link_elf_leak_locals)
1693 return (link_elf_debug_symbol_values(lf, sym, symval));
1694 return (link_elf_symbol_values1(lf, sym, symval, false));
1695 }
1696
1697 static int
link_elf_debug_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1698 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1699 linker_symval_t *symval)
1700 {
1701 elf_file_t ef = (elf_file_t)lf;
1702 const Elf_Sym *es = (const Elf_Sym *)sym;
1703 caddr_t val;
1704 size_t size;
1705
1706 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1707 return (0);
1708 if (ef->symtab == ef->ddbsymtab)
1709 return (ENOENT);
1710
1711 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1712 symval->name = ef->ddbstrtab + es->st_name;
1713 val = (caddr_t)ef->address + es->st_value;
1714 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1715 link_elf_ifunc_symbol_value(lf, &val, &size);
1716 else
1717 size = es->st_size;
1718 symval->value = val;
1719 symval->size = size;
1720 return (0);
1721 }
1722 return (ENOENT);
1723 }
1724
1725 static int
link_elf_search_symbol(linker_file_t lf,caddr_t value,c_linker_sym_t * sym,long * diffp)1726 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1727 c_linker_sym_t *sym, long *diffp)
1728 {
1729 elf_file_t ef = (elf_file_t)lf;
1730 u_long off = (uintptr_t)(void *)value;
1731 u_long diff = off;
1732 u_long st_value;
1733 const Elf_Sym *es;
1734 const Elf_Sym *best = NULL;
1735 int i;
1736
1737 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1738 if (es->st_name == 0)
1739 continue;
1740 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1741 if (off >= st_value) {
1742 if (off - st_value < diff) {
1743 diff = off - st_value;
1744 best = es;
1745 if (diff == 0)
1746 break;
1747 } else if (off - st_value == diff) {
1748 best = es;
1749 }
1750 }
1751 }
1752 if (best == NULL)
1753 *diffp = off;
1754 else
1755 *diffp = diff;
1756 *sym = (c_linker_sym_t) best;
1757
1758 return (0);
1759 }
1760
1761 /*
1762 * Look up a linker set on an ELF system.
1763 */
1764 static int
link_elf_lookup_set(linker_file_t lf,const char * name,void *** startp,void *** stopp,int * countp)1765 link_elf_lookup_set(linker_file_t lf, const char *name,
1766 void ***startp, void ***stopp, int *countp)
1767 {
1768 c_linker_sym_t sym;
1769 linker_symval_t symval;
1770 char *setsym;
1771 void **start, **stop;
1772 int len, error = 0, count;
1773
1774 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1775 setsym = malloc(len, M_LINKER, M_WAITOK);
1776
1777 /* get address of first entry */
1778 snprintf(setsym, len, "%s%s", "__start_set_", name);
1779 error = link_elf_lookup_symbol(lf, setsym, &sym);
1780 if (error != 0)
1781 goto out;
1782 link_elf_symbol_values(lf, sym, &symval);
1783 if (symval.value == 0) {
1784 error = ESRCH;
1785 goto out;
1786 }
1787 start = (void **)symval.value;
1788
1789 /* get address of last entry */
1790 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1791 error = link_elf_lookup_symbol(lf, setsym, &sym);
1792 if (error != 0)
1793 goto out;
1794 link_elf_symbol_values(lf, sym, &symval);
1795 if (symval.value == 0) {
1796 error = ESRCH;
1797 goto out;
1798 }
1799 stop = (void **)symval.value;
1800
1801 /* and the number of entries */
1802 count = stop - start;
1803
1804 /* and copy out */
1805 if (startp != NULL)
1806 *startp = start;
1807 if (stopp != NULL)
1808 *stopp = stop;
1809 if (countp != NULL)
1810 *countp = count;
1811
1812 out:
1813 free(setsym, M_LINKER);
1814 return (error);
1815 }
1816
1817 static int
link_elf_each_function_name(linker_file_t file,int (* callback)(const char *,void *),void * opaque)1818 link_elf_each_function_name(linker_file_t file,
1819 int (*callback)(const char *, void *), void *opaque)
1820 {
1821 elf_file_t ef = (elf_file_t)file;
1822 const Elf_Sym *symp;
1823 int i, error;
1824
1825 /* Exhaustive search */
1826 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1827 if (symp->st_value != 0 &&
1828 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1829 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1830 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1831 if (error != 0)
1832 return (error);
1833 }
1834 }
1835 return (0);
1836 }
1837
1838 static int
link_elf_each_function_nameval(linker_file_t file,linker_function_nameval_callback_t callback,void * opaque)1839 link_elf_each_function_nameval(linker_file_t file,
1840 linker_function_nameval_callback_t callback, void *opaque)
1841 {
1842 linker_symval_t symval;
1843 elf_file_t ef = (elf_file_t)file;
1844 const Elf_Sym *symp;
1845 int i, error;
1846
1847 /* Exhaustive search */
1848 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1849 if (symp->st_value != 0 &&
1850 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1851 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1852 error = link_elf_debug_symbol_values(file,
1853 (c_linker_sym_t) symp, &symval);
1854 if (error == 0)
1855 error = callback(file, i, &symval, opaque);
1856 if (error != 0)
1857 return (error);
1858 }
1859 }
1860 return (0);
1861 }
1862
1863 const Elf_Sym *
elf_get_sym(linker_file_t lf,Elf_Size symidx)1864 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1865 {
1866 elf_file_t ef = (elf_file_t)lf;
1867
1868 if (symidx >= ef->nchains)
1869 return (NULL);
1870 return (ef->symtab + symidx);
1871 }
1872
1873 const char *
elf_get_symname(linker_file_t lf,Elf_Size symidx)1874 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1875 {
1876 elf_file_t ef = (elf_file_t)lf;
1877 const Elf_Sym *sym;
1878
1879 if (symidx >= ef->nchains)
1880 return (NULL);
1881 sym = ef->symtab + symidx;
1882 return (ef->strtab + sym->st_name);
1883 }
1884
1885 /*
1886 * Symbol lookup function that can be used when the symbol index is known (ie
1887 * in relocations). It uses the symbol index instead of doing a fully fledged
1888 * hash table based lookup when such is valid. For example for local symbols.
1889 * This is not only more efficient, it's also more correct. It's not always
1890 * the case that the symbol can be found through the hash table.
1891 */
1892 static int
elf_lookup(linker_file_t lf,Elf_Size symidx,int deps,Elf_Addr * res)1893 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1894 {
1895 elf_file_t ef = (elf_file_t)lf;
1896 const Elf_Sym *sym;
1897 const char *symbol;
1898 Elf_Addr addr, start, base;
1899
1900 /* Don't even try to lookup the symbol if the index is bogus. */
1901 if (symidx >= ef->nchains) {
1902 *res = 0;
1903 return (EINVAL);
1904 }
1905
1906 sym = ef->symtab + symidx;
1907
1908 /*
1909 * Don't do a full lookup when the symbol is local. It may even
1910 * fail because it may not be found through the hash table.
1911 */
1912 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1913 /* Force lookup failure when we have an insanity. */
1914 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1915 *res = 0;
1916 return (EINVAL);
1917 }
1918 *res = ((Elf_Addr)ef->address + sym->st_value);
1919 return (0);
1920 }
1921
1922 /*
1923 * XXX we can avoid doing a hash table based lookup for global
1924 * symbols as well. This however is not always valid, so we'll
1925 * just do it the hard way for now. Performance tweaks can
1926 * always be added.
1927 */
1928
1929 symbol = ef->strtab + sym->st_name;
1930
1931 /* Force a lookup failure if the symbol name is bogus. */
1932 if (*symbol == 0) {
1933 *res = 0;
1934 return (EINVAL);
1935 }
1936
1937 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1938 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1939 *res = 0;
1940 return (EINVAL);
1941 }
1942
1943 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1944 addr = addr - start + base;
1945 #ifdef VIMAGE
1946 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1947 addr = addr - start + base;
1948 #endif
1949 *res = addr;
1950 return (0);
1951 }
1952
1953 static void
link_elf_reloc_local(linker_file_t lf)1954 link_elf_reloc_local(linker_file_t lf)
1955 {
1956 const Elf_Rel *rellim;
1957 const Elf_Rel *rel;
1958 const Elf_Rela *relalim;
1959 const Elf_Rela *rela;
1960 elf_file_t ef = (elf_file_t)lf;
1961
1962 /* Perform relocations without addend if there are any: */
1963 if ((rel = ef->rel) != NULL) {
1964 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1965 while (rel < rellim) {
1966 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1967 ELF_RELOC_REL, elf_lookup);
1968 rel++;
1969 }
1970 }
1971
1972 /* Perform relocations with addend if there are any: */
1973 if ((rela = ef->rela) != NULL) {
1974 relalim = (const Elf_Rela *)
1975 ((const char *)ef->rela + ef->relasize);
1976 while (rela < relalim) {
1977 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1978 ELF_RELOC_RELA, elf_lookup);
1979 rela++;
1980 }
1981 }
1982 }
1983
1984 static long
link_elf_symtab_get(linker_file_t lf,const Elf_Sym ** symtab)1985 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1986 {
1987 elf_file_t ef = (elf_file_t)lf;
1988
1989 *symtab = ef->ddbsymtab;
1990
1991 if (*symtab == NULL)
1992 return (0);
1993
1994 return (ef->ddbsymcnt);
1995 }
1996
1997 static long
link_elf_strtab_get(linker_file_t lf,caddr_t * strtab)1998 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1999 {
2000 elf_file_t ef = (elf_file_t)lf;
2001
2002 *strtab = ef->ddbstrtab;
2003
2004 if (*strtab == NULL)
2005 return (0);
2006
2007 return (ef->ddbstrcnt);
2008 }
2009
2010 #ifdef VIMAGE
2011 static void
link_elf_propagate_vnets(linker_file_t lf)2012 link_elf_propagate_vnets(linker_file_t lf)
2013 {
2014 elf_file_t ef = (elf_file_t)lf;
2015 int size;
2016
2017 if (ef->vnet_base != 0) {
2018 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
2019 vnet_data_copy((void *)ef->vnet_base, size);
2020 }
2021 }
2022 #endif
2023
2024 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
2025 /*
2026 * Use this lookup routine when performing relocations early during boot.
2027 * The generic lookup routine depends on kobj, which is not initialized
2028 * at that point.
2029 */
2030 static int
elf_lookup_ifunc(linker_file_t lf,Elf_Size symidx,int deps __unused,Elf_Addr * res)2031 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
2032 Elf_Addr *res)
2033 {
2034 elf_file_t ef;
2035 const Elf_Sym *symp;
2036 caddr_t val;
2037
2038 ef = (elf_file_t)lf;
2039 symp = ef->symtab + symidx;
2040 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
2041 val = (caddr_t)ef->address + symp->st_value;
2042 *res = ((Elf_Addr (*)(void))val)();
2043 return (0);
2044 }
2045 return (ENOENT);
2046 }
2047
2048 void
link_elf_ireloc(void)2049 link_elf_ireloc(void)
2050 {
2051 struct elf_file eff;
2052 elf_file_t ef;
2053
2054 TSENTER();
2055 ef = &eff;
2056
2057 bzero_early(ef, sizeof(*ef));
2058
2059 ef->modptr = preload_kmdp;
2060 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
2061
2062 #ifdef RELOCATABLE_KERNEL
2063 ef->address = (caddr_t) (__startkernel - KERNBASE);
2064 #else
2065 ef->address = 0;
2066 #endif
2067 parse_dynamic(ef);
2068
2069 link_elf_preload_parse_symbols(ef);
2070 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
2071 TSEXIT();
2072 }
2073
2074 #if defined(__aarch64__) || defined(__amd64__)
2075 void
link_elf_late_ireloc(void)2076 link_elf_late_ireloc(void)
2077 {
2078 elf_file_t ef;
2079
2080 KASSERT(linker_kernel_file != NULL,
2081 ("link_elf_late_ireloc: No kernel linker file found"));
2082 ef = (elf_file_t)linker_kernel_file;
2083
2084 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);
2085 }
2086 #endif
2087 #endif
2088