xref: /f-stack/freebsd/kern/link_elf.c (revision 22ce4aff)
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("$FreeBSD$");
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 #include <sys/sysctl.h>
55 
56 #include <machine/elf.h>
57 
58 #include <net/vnet.h>
59 
60 #include <security/mac/mac_framework.h>
61 
62 #include <vm/vm.h>
63 #include <vm/vm_param.h>
64 #ifdef SPARSE_MAPPING
65 #include <vm/vm_object.h>
66 #include <vm/vm_kern.h>
67 #include <vm/vm_extern.h>
68 #endif
69 #include <vm/pmap.h>
70 #include <vm/vm_map.h>
71 
72 #include <sys/link_elf.h>
73 
74 #include "linker_if.h"
75 
76 #define MAXSEGS 4
77 
78 typedef struct elf_file {
79 	struct linker_file lf;		/* Common fields */
80 	int		preloaded;	/* Was file pre-loaded */
81 	caddr_t		address;	/* Relocation address */
82 #ifdef SPARSE_MAPPING
83 	vm_object_t	object;		/* VM object to hold file pages */
84 #endif
85 	Elf_Dyn		*dynamic;	/* Symbol table etc. */
86 	Elf_Hashelt	nbuckets;	/* DT_HASH info */
87 	Elf_Hashelt	nchains;
88 	const Elf_Hashelt *buckets;
89 	const Elf_Hashelt *chains;
90 	caddr_t		hash;
91 	caddr_t		strtab;		/* DT_STRTAB */
92 	int		strsz;		/* DT_STRSZ */
93 	const Elf_Sym	*symtab;		/* DT_SYMTAB */
94 	Elf_Addr	*got;		/* DT_PLTGOT */
95 	const Elf_Rel	*pltrel;	/* DT_JMPREL */
96 	int		pltrelsize;	/* DT_PLTRELSZ */
97 	const Elf_Rela	*pltrela;	/* DT_JMPREL */
98 	int		pltrelasize;	/* DT_PLTRELSZ */
99 	const Elf_Rel	*rel;		/* DT_REL */
100 	int		relsize;	/* DT_RELSZ */
101 	const Elf_Rela	*rela;		/* DT_RELA */
102 	int		relasize;	/* DT_RELASZ */
103 	caddr_t		modptr;
104 	const Elf_Sym	*ddbsymtab;	/* The symbol table we are using */
105 	long		ddbsymcnt;	/* Number of symbols */
106 	caddr_t		ddbstrtab;	/* String table */
107 	long		ddbstrcnt;	/* number of bytes in string table */
108 	caddr_t		symbase;	/* malloc'ed symbold base */
109 	caddr_t		strbase;	/* malloc'ed string base */
110 	caddr_t		ctftab;		/* CTF table */
111 	long		ctfcnt;		/* number of bytes in CTF table */
112 	caddr_t		ctfoff;		/* CTF offset table */
113 	caddr_t		typoff;		/* Type offset table */
114 	long		typlen;		/* Number of type entries. */
115 	Elf_Addr	pcpu_start;	/* Pre-relocation pcpu set start. */
116 	Elf_Addr	pcpu_stop;	/* Pre-relocation pcpu set stop. */
117 	Elf_Addr	pcpu_base;	/* Relocated pcpu set address. */
118 #ifdef VIMAGE
119 	Elf_Addr	vnet_start;	/* Pre-relocation vnet set start. */
120 	Elf_Addr	vnet_stop;	/* Pre-relocation vnet set stop. */
121 	Elf_Addr	vnet_base;	/* Relocated vnet set address. */
122 #endif
123 #ifdef GDB
124 	struct link_map	gdb;		/* hooks for gdb */
125 #endif
126 } *elf_file_t;
127 
128 struct elf_set {
129 	Elf_Addr	es_start;
130 	Elf_Addr	es_stop;
131 	Elf_Addr	es_base;
132 	TAILQ_ENTRY(elf_set)	es_link;
133 };
134 
135 TAILQ_HEAD(elf_set_head, elf_set);
136 
137 #include <kern/kern_ctf.c>
138 
139 static int	link_elf_link_common_finish(linker_file_t);
140 static int	link_elf_link_preload(linker_class_t cls,
141 				      const char *, linker_file_t *);
142 static int	link_elf_link_preload_finish(linker_file_t);
143 static int	link_elf_load_file(linker_class_t, const char *,
144 		    linker_file_t *);
145 static int	link_elf_lookup_symbol(linker_file_t, const char *,
146 		    c_linker_sym_t *);
147 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
148 		    linker_symval_t *);
149 static int	link_elf_search_symbol(linker_file_t, caddr_t,
150 		    c_linker_sym_t *, long *);
151 
152 static void	link_elf_unload_file(linker_file_t);
153 static void	link_elf_unload_preload(linker_file_t);
154 static int	link_elf_lookup_set(linker_file_t, const char *,
155 		    void ***, void ***, int *);
156 static int	link_elf_each_function_name(linker_file_t,
157 		    int (*)(const char *, void *), void *);
158 static int	link_elf_each_function_nameval(linker_file_t,
159 		    linker_function_nameval_callback_t, void *);
160 static void	link_elf_reloc_local(linker_file_t);
161 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
162 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
163 static int	elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
164 
165 static kobj_method_t link_elf_methods[] = {
166 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
167 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
168 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
169 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
170 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
171 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
172 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
173 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
174 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
175 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
176 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
177 	KOBJMETHOD(linker_symtab_get,		link_elf_symtab_get),
178 	KOBJMETHOD(linker_strtab_get,		link_elf_strtab_get),
179 	KOBJMETHOD_END
180 };
181 
182 static struct linker_class link_elf_class = {
183 #if ELF_TARG_CLASS == ELFCLASS32
184 	"elf32",
185 #else
186 	"elf64",
187 #endif
188 	link_elf_methods, sizeof(struct elf_file)
189 };
190 
191 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
192     const void *data, int type, elf_lookup_fn lookup);
193 
194 static int	parse_dynamic(elf_file_t);
195 static int	relocate_file(elf_file_t);
196 static int	relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
197 		    elf_reloc_fn reloc, bool ifuncs);
198 static int	link_elf_preload_parse_symbols(elf_file_t);
199 
200 static struct elf_set_head set_pcpu_list;
201 #ifdef VIMAGE
202 static struct elf_set_head set_vnet_list;
203 #endif
204 
205 static void
elf_set_add(struct elf_set_head * list,Elf_Addr start,Elf_Addr stop,Elf_Addr base)206 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
207 {
208 	struct elf_set *set, *iter;
209 
210 	set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
211 	set->es_start = start;
212 	set->es_stop = stop;
213 	set->es_base = base;
214 
215 	TAILQ_FOREACH(iter, list, es_link) {
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 #ifdef RELOCATABLE_KERNEL
391 /*
392  * __startkernel and __endkernel are symbols set up as relocation canaries.
393  *
394  * They are defined in locore to reference linker script symbols at the
395  * beginning and end of the LOAD area. This has the desired side effect of
396  * giving us variables that have relative relocations pointing at them, so
397  * relocation of the kernel object will cause the variables to be updated
398  * automatically by the runtime linker when we initialize.
399  *
400  * There are two main reasons to relocate the kernel:
401  * 1) If the loader needed to load the kernel at an alternate load address.
402  * 2) If the kernel is switching address spaces on machines like POWER9
403  *    under Radix where the high bits of the effective address are used to
404  *    differentiate between hypervisor, host, guest, and problem state.
405  */
406 extern vm_offset_t __startkernel, __endkernel;
407 #endif
408 
409 static unsigned long kern_relbase = KERNBASE;
410 
411 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
412 	SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
413 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
414 	&kern_relbase, 0, "Kernel relocated base address");
415 
416 static void
link_elf_init(void * arg)417 link_elf_init(void* arg)
418 {
419 	Elf_Dyn *dp;
420 	Elf_Addr *ctors_addrp;
421 	Elf_Size *ctors_sizep;
422 	caddr_t modptr, baseptr, sizeptr;
423 	elf_file_t ef;
424 	const char *modname;
425 
426 	linker_add_class(&link_elf_class);
427 
428 	dp = (Elf_Dyn *)&_DYNAMIC;
429 	modname = NULL;
430 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
431 	if (modptr == NULL)
432 		modptr = preload_search_by_type("elf kernel");
433 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
434 	if (modname == NULL)
435 		modname = "kernel";
436 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
437 	if (linker_kernel_file == NULL)
438 		panic("%s: Can't create linker structures for kernel",
439 		    __func__);
440 
441 	ef = (elf_file_t) linker_kernel_file;
442 	ef->preloaded = 1;
443 #ifdef RELOCATABLE_KERNEL
444 	/* Compute relative displacement */
445 	ef->address = (caddr_t) (__startkernel - KERNBASE);
446 #else
447 	ef->address = 0;
448 #endif
449 #ifdef SPARSE_MAPPING
450 	ef->object = NULL;
451 #endif
452 	ef->dynamic = dp;
453 
454 	if (dp != NULL)
455 		parse_dynamic(ef);
456 #ifdef RELOCATABLE_KERNEL
457 	linker_kernel_file->address = (caddr_t)__startkernel;
458 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
459 	kern_relbase = (unsigned long)__startkernel;
460 #else
461 	linker_kernel_file->address += KERNBASE;
462 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
463 #endif
464 
465 	if (modptr != NULL) {
466 		ef->modptr = modptr;
467 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
468 		if (baseptr != NULL)
469 			linker_kernel_file->address = *(caddr_t *)baseptr;
470 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
471 		if (sizeptr != NULL)
472 			linker_kernel_file->size = *(size_t *)sizeptr;
473 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
474 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
475 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
476 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
477 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
478 			linker_kernel_file->ctors_addr = ef->address +
479 			    *ctors_addrp;
480 			linker_kernel_file->ctors_size = *ctors_sizep;
481 		}
482 	}
483 	(void)link_elf_preload_parse_symbols(ef);
484 
485 #ifdef GDB
486 	r_debug.r_map = NULL;
487 	r_debug.r_brk = r_debug_state;
488 	r_debug.r_state = RT_CONSISTENT;
489 #endif
490 
491 	(void)link_elf_link_common_finish(linker_kernel_file);
492 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
493 	TAILQ_INIT(&set_pcpu_list);
494 #ifdef VIMAGE
495 	TAILQ_INIT(&set_vnet_list);
496 #endif
497 }
498 
499 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
500 
501 static int
link_elf_preload_parse_symbols(elf_file_t ef)502 link_elf_preload_parse_symbols(elf_file_t ef)
503 {
504 	caddr_t pointer;
505 	caddr_t ssym, esym, base;
506 	caddr_t strtab;
507 	int strcnt;
508 	Elf_Sym *symtab;
509 	int symcnt;
510 
511 	if (ef->modptr == NULL)
512 		return (0);
513 	pointer = preload_search_info(ef->modptr,
514 	    MODINFO_METADATA | MODINFOMD_SSYM);
515 	if (pointer == NULL)
516 		return (0);
517 	ssym = *(caddr_t *)pointer;
518 	pointer = preload_search_info(ef->modptr,
519 	    MODINFO_METADATA | MODINFOMD_ESYM);
520 	if (pointer == NULL)
521 		return (0);
522 	esym = *(caddr_t *)pointer;
523 
524 	base = ssym;
525 
526 	symcnt = *(long *)base;
527 	base += sizeof(long);
528 	symtab = (Elf_Sym *)base;
529 	base += roundup(symcnt, sizeof(long));
530 
531 	if (base > esym || base < ssym) {
532 		printf("Symbols are corrupt!\n");
533 		return (EINVAL);
534 	}
535 
536 	strcnt = *(long *)base;
537 	base += sizeof(long);
538 	strtab = base;
539 	base += roundup(strcnt, sizeof(long));
540 
541 	if (base > esym || base < ssym) {
542 		printf("Symbols are corrupt!\n");
543 		return (EINVAL);
544 	}
545 
546 	ef->ddbsymtab = symtab;
547 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
548 	ef->ddbstrtab = strtab;
549 	ef->ddbstrcnt = strcnt;
550 
551 	return (0);
552 }
553 
554 static int
parse_dynamic(elf_file_t ef)555 parse_dynamic(elf_file_t ef)
556 {
557 	Elf_Dyn *dp;
558 	int plttype = DT_REL;
559 
560 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
561 		switch (dp->d_tag) {
562 		case DT_HASH:
563 		{
564 			/* From src/libexec/rtld-elf/rtld.c */
565 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
566 			    (ef->address + dp->d_un.d_ptr);
567 			ef->nbuckets = hashtab[0];
568 			ef->nchains = hashtab[1];
569 			ef->buckets = hashtab + 2;
570 			ef->chains = ef->buckets + ef->nbuckets;
571 			break;
572 		}
573 		case DT_STRTAB:
574 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
575 			break;
576 		case DT_STRSZ:
577 			ef->strsz = dp->d_un.d_val;
578 			break;
579 		case DT_SYMTAB:
580 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
581 			break;
582 		case DT_SYMENT:
583 			if (dp->d_un.d_val != sizeof(Elf_Sym))
584 				return (ENOEXEC);
585 			break;
586 		case DT_PLTGOT:
587 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
588 			break;
589 		case DT_REL:
590 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
591 			break;
592 		case DT_RELSZ:
593 			ef->relsize = dp->d_un.d_val;
594 			break;
595 		case DT_RELENT:
596 			if (dp->d_un.d_val != sizeof(Elf_Rel))
597 				return (ENOEXEC);
598 			break;
599 		case DT_JMPREL:
600 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
601 			break;
602 		case DT_PLTRELSZ:
603 			ef->pltrelsize = dp->d_un.d_val;
604 			break;
605 		case DT_RELA:
606 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
607 			break;
608 		case DT_RELASZ:
609 			ef->relasize = dp->d_un.d_val;
610 			break;
611 		case DT_RELAENT:
612 			if (dp->d_un.d_val != sizeof(Elf_Rela))
613 				return (ENOEXEC);
614 			break;
615 		case DT_PLTREL:
616 			plttype = dp->d_un.d_val;
617 			if (plttype != DT_REL && plttype != DT_RELA)
618 				return (ENOEXEC);
619 			break;
620 #ifdef GDB
621 		case DT_DEBUG:
622 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
623 			break;
624 #endif
625 		}
626 	}
627 
628 	if (plttype == DT_RELA) {
629 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
630 		ef->pltrel = NULL;
631 		ef->pltrelasize = ef->pltrelsize;
632 		ef->pltrelsize = 0;
633 	}
634 
635 	ef->ddbsymtab = ef->symtab;
636 	ef->ddbsymcnt = ef->nchains;
637 	ef->ddbstrtab = ef->strtab;
638 	ef->ddbstrcnt = ef->strsz;
639 
640 #ifndef FSTACK
641 	return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
642 #else
643 	return 0;
644 #endif
645 }
646 
647 #define	LS_PADDING	0x90909090
648 static int
parse_dpcpu(elf_file_t ef)649 parse_dpcpu(elf_file_t ef)
650 {
651 	int error, size;
652 #if defined(__i386__)
653 	uint32_t pad;
654 #endif
655 
656 	ef->pcpu_start = 0;
657 	ef->pcpu_stop = 0;
658 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
659 	    (void ***)&ef->pcpu_stop, NULL);
660 	/* Error just means there is no pcpu set to relocate. */
661 	if (error != 0)
662 		return (0);
663 	size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
664 	/* Empty set? */
665 	if (size < 1)
666 		return (0);
667 #if defined(__i386__)
668 	/* In case we do find __start/stop_set_ symbols double-check. */
669 	if (size < 4) {
670 		uprintf("Kernel module '%s' must be recompiled with "
671 		    "linker script\n", ef->lf.pathname);
672 		return (ENOEXEC);
673 	}
674 
675 	/* Padding from linker-script correct? */
676 	pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
677 	if (pad != LS_PADDING) {
678 		uprintf("Kernel module '%s' must be recompiled with "
679 		    "linker script, invalid padding %#04x (%#04x)\n",
680 		    ef->lf.pathname, pad, LS_PADDING);
681 		return (ENOEXEC);
682 	}
683 	/* If we only have valid padding, nothing to do. */
684 	if (size == 4)
685 		return (0);
686 #endif
687 	/*
688 	 * Allocate space in the primary pcpu area.  Copy in our
689 	 * initialization from the data section and then initialize
690 	 * all per-cpu storage from that.
691 	 */
692 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
693 	if (ef->pcpu_base == 0) {
694 		printf("%s: pcpu module space is out of space; "
695 		    "cannot allocate %d for %s\n",
696 		    __func__, size, ef->lf.pathname);
697 		return (ENOSPC);
698 	}
699 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
700 	dpcpu_copy((void *)ef->pcpu_base, size);
701 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
702 	    ef->pcpu_base);
703 
704 	return (0);
705 }
706 
707 #ifdef VIMAGE
708 static int
parse_vnet(elf_file_t ef)709 parse_vnet(elf_file_t ef)
710 {
711 	int error, size;
712 #if defined(__i386__)
713 	uint32_t pad;
714 #endif
715 
716 	ef->vnet_start = 0;
717 	ef->vnet_stop = 0;
718 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
719 	    (void ***)&ef->vnet_stop, NULL);
720 	/* Error just means there is no vnet data set to relocate. */
721 	if (error != 0)
722 		return (0);
723 	size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
724 	/* Empty set? */
725 	if (size < 1)
726 		return (0);
727 #if defined(__i386__)
728 	/* In case we do find __start/stop_set_ symbols double-check. */
729 	if (size < 4) {
730 		uprintf("Kernel module '%s' must be recompiled with "
731 		    "linker script\n", ef->lf.pathname);
732 		return (ENOEXEC);
733 	}
734 
735 	/* Padding from linker-script correct? */
736 	pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
737 	if (pad != LS_PADDING) {
738 		uprintf("Kernel module '%s' must be recompiled with "
739 		    "linker script, invalid padding %#04x (%#04x)\n",
740 		    ef->lf.pathname, pad, LS_PADDING);
741 		return (ENOEXEC);
742 	}
743 	/* If we only have valid padding, nothing to do. */
744 	if (size == 4)
745 		return (0);
746 #endif
747 	/*
748 	 * Allocate space in the primary vnet area.  Copy in our
749 	 * initialization from the data section and then initialize
750 	 * all per-vnet storage from that.
751 	 */
752 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
753 	if (ef->vnet_base == 0) {
754 		printf("%s: vnet module space is out of space; "
755 		    "cannot allocate %d for %s\n",
756 		    __func__, size, ef->lf.pathname);
757 		return (ENOSPC);
758 	}
759 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
760 	vnet_data_copy((void *)ef->vnet_base, size);
761 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
762 	    ef->vnet_base);
763 
764 	return (0);
765 }
766 #endif
767 #undef LS_PADDING
768 
769 /*
770  * Apply the specified protection to the loadable segments of a preloaded linker
771  * file.
772  */
773 static int
preload_protect(elf_file_t ef,vm_prot_t prot)774 preload_protect(elf_file_t ef, vm_prot_t prot)
775 {
776 #ifdef __amd64__
777 	Elf_Ehdr *hdr;
778 	Elf_Phdr *phdr, *phlimit;
779 	vm_prot_t nprot;
780 	int error;
781 
782 	error = 0;
783 	hdr = (Elf_Ehdr *)ef->address;
784 	phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
785 	phlimit = phdr + hdr->e_phnum;
786 	for (; phdr < phlimit; phdr++) {
787 		if (phdr->p_type != PT_LOAD)
788 			continue;
789 
790 		nprot = prot | VM_PROT_READ;
791 		if ((phdr->p_flags & PF_W) != 0)
792 			nprot |= VM_PROT_WRITE;
793 		if ((phdr->p_flags & PF_X) != 0)
794 			nprot |= VM_PROT_EXECUTE;
795 		error = pmap_change_prot((vm_offset_t)ef->address +
796 		    phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
797 		if (error != 0)
798 			break;
799 	}
800 	return (error);
801 #else
802 	return (0);
803 #endif
804 }
805 
806 #ifdef __arm__
807 /*
808  * Locate the ARM exception/unwind table info for DDB and stack(9) use by
809  * searching for the section header that describes it.  There may be no unwind
810  * info, for example in a module containing only data.
811  */
812 static void
link_elf_locate_exidx(linker_file_t lf,Elf_Shdr * shdr,int nhdr)813 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
814 {
815 	int i;
816 
817 	for (i = 0; i < nhdr; i++) {
818 		if (shdr[i].sh_type == SHT_ARM_EXIDX) {
819 			lf->exidx_addr = shdr[i].sh_addr + lf->address;
820 			lf->exidx_size = shdr[i].sh_size;
821 			break;
822 		}
823 	}
824 }
825 
826 /*
827  * Locate the section headers metadata in a preloaded module, then use it to
828  * locate the exception/unwind table in the module.  The size of the metadata
829  * block is stored in a uint32 word immediately before the data itself, and a
830  * comment in preload_search_info() says it is safe to rely on that.
831  */
832 static void
link_elf_locate_exidx_preload(struct linker_file * lf,caddr_t modptr)833 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
834 {
835 	uint32_t *modinfo;
836 	Elf_Shdr *shdr;
837 	uint32_t  nhdr;
838 
839 	modinfo = (uint32_t *)preload_search_info(modptr,
840 	    MODINFO_METADATA | MODINFOMD_SHDR);
841 	if (modinfo != NULL) {
842 		shdr = (Elf_Shdr *)modinfo;
843 		nhdr = modinfo[-1] / sizeof(Elf_Shdr);
844 		link_elf_locate_exidx(lf, shdr, nhdr);
845 	}
846 }
847 
848 #endif /* __arm__ */
849 
850 static int
link_elf_link_preload(linker_class_t cls,const char * filename,linker_file_t * result)851 link_elf_link_preload(linker_class_t cls, const char *filename,
852     linker_file_t *result)
853 {
854 	Elf_Addr *ctors_addrp;
855 	Elf_Size *ctors_sizep;
856 	caddr_t modptr, baseptr, sizeptr, dynptr;
857 	char *type;
858 	elf_file_t ef;
859 	linker_file_t lf;
860 	int error;
861 	vm_offset_t dp;
862 
863 	/* Look to see if we have the file preloaded */
864 	modptr = preload_search_by_name(filename);
865 	if (modptr == NULL)
866 		return (ENOENT);
867 
868 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
869 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
870 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
871 	dynptr = preload_search_info(modptr,
872 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
873 	if (type == NULL ||
874 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
875 	     strcmp(type, "elf module") != 0))
876 		return (EFTYPE);
877 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
878 		return (EINVAL);
879 
880 	lf = linker_make_file(filename, &link_elf_class);
881 	if (lf == NULL)
882 		return (ENOMEM);
883 
884 	ef = (elf_file_t) lf;
885 	ef->preloaded = 1;
886 	ef->modptr = modptr;
887 	ef->address = *(caddr_t *)baseptr;
888 #ifdef SPARSE_MAPPING
889 	ef->object = NULL;
890 #endif
891 	dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
892 	ef->dynamic = (Elf_Dyn *)dp;
893 	lf->address = ef->address;
894 	lf->size = *(size_t *)sizeptr;
895 
896 	ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
897 	    MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
898 	ctors_sizep = (Elf_Size *)preload_search_info(modptr,
899 	    MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
900 	if (ctors_addrp != NULL && ctors_sizep != NULL) {
901 		lf->ctors_addr = ef->address + *ctors_addrp;
902 		lf->ctors_size = *ctors_sizep;
903 	}
904 
905 #ifdef __arm__
906 	link_elf_locate_exidx_preload(lf, modptr);
907 #endif
908 
909 	error = parse_dynamic(ef);
910 	if (error == 0)
911 		error = parse_dpcpu(ef);
912 #ifdef VIMAGE
913 	if (error == 0)
914 		error = parse_vnet(ef);
915 #endif
916 	if (error == 0)
917 		error = preload_protect(ef, VM_PROT_ALL);
918 	if (error != 0) {
919 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
920 		return (error);
921 	}
922 	link_elf_reloc_local(lf);
923 	*result = lf;
924 	return (0);
925 }
926 
927 static int
link_elf_link_preload_finish(linker_file_t lf)928 link_elf_link_preload_finish(linker_file_t lf)
929 {
930 	elf_file_t ef;
931 	int error;
932 
933 	ef = (elf_file_t) lf;
934 	error = relocate_file(ef);
935 	if (error == 0)
936 		error = preload_protect(ef, VM_PROT_NONE);
937 	if (error != 0)
938 		return (error);
939 	(void)link_elf_preload_parse_symbols(ef);
940 
941 	return (link_elf_link_common_finish(lf));
942 }
943 
944 static int
link_elf_load_file(linker_class_t cls,const char * filename,linker_file_t * result)945 link_elf_load_file(linker_class_t cls, const char* filename,
946     linker_file_t* result)
947 {
948 	struct nameidata nd;
949 	struct thread* td = curthread;	/* XXX */
950 	Elf_Ehdr *hdr;
951 	caddr_t firstpage, segbase;
952 	int nbytes, i;
953 	Elf_Phdr *phdr;
954 	Elf_Phdr *phlimit;
955 	Elf_Phdr *segs[MAXSEGS];
956 	int nsegs;
957 	Elf_Phdr *phdyn;
958 	caddr_t mapbase;
959 	size_t mapsize;
960 	Elf_Addr base_vaddr;
961 	Elf_Addr base_vlimit;
962 	int error = 0;
963 	ssize_t resid;
964 	int flags;
965 	elf_file_t ef;
966 	linker_file_t lf;
967 	Elf_Shdr *shdr;
968 	int symtabindex;
969 	int symstrindex;
970 	int shstrindex;
971 	int symcnt;
972 	int strcnt;
973 	char *shstrs;
974 
975 	shdr = NULL;
976 	lf = NULL;
977 	shstrs = NULL;
978 
979 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
980 	flags = FREAD;
981 	error = vn_open(&nd, &flags, 0, NULL);
982 	if (error != 0)
983 		return (error);
984 	NDFREE(&nd, NDF_ONLY_PNBUF);
985 	if (nd.ni_vp->v_type != VREG) {
986 		error = ENOEXEC;
987 		firstpage = NULL;
988 		goto out;
989 	}
990 #ifdef MAC
991 	error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
992 	if (error != 0) {
993 		firstpage = NULL;
994 		goto out;
995 	}
996 #endif
997 
998 	/*
999 	 * Read the elf header from the file.
1000 	 */
1001 	firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1002 	hdr = (Elf_Ehdr *)firstpage;
1003 	error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1004 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1005 	    &resid, td);
1006 	nbytes = PAGE_SIZE - resid;
1007 	if (error != 0)
1008 		goto out;
1009 
1010 	if (!IS_ELF(*hdr)) {
1011 		error = ENOEXEC;
1012 		goto out;
1013 	}
1014 
1015 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1016 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1017 		link_elf_error(filename, "Unsupported file layout");
1018 		error = ENOEXEC;
1019 		goto out;
1020 	}
1021 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1022 	    hdr->e_version != EV_CURRENT) {
1023 		link_elf_error(filename, "Unsupported file version");
1024 		error = ENOEXEC;
1025 		goto out;
1026 	}
1027 	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1028 		error = ENOSYS;
1029 		goto out;
1030 	}
1031 	if (hdr->e_machine != ELF_TARG_MACH) {
1032 		link_elf_error(filename, "Unsupported machine");
1033 		error = ENOEXEC;
1034 		goto out;
1035 	}
1036 
1037 	/*
1038 	 * We rely on the program header being in the first page.
1039 	 * This is not strictly required by the ABI specification, but
1040 	 * it seems to always true in practice.  And, it simplifies
1041 	 * things considerably.
1042 	 */
1043 	if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1044 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1045 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1046 		link_elf_error(filename, "Unreadable program headers");
1047 
1048 	/*
1049 	 * Scan the program header entries, and save key information.
1050 	 *
1051 	 * We rely on there being exactly two load segments, text and data,
1052 	 * in that order.
1053 	 */
1054 	phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1055 	phlimit = phdr + hdr->e_phnum;
1056 	nsegs = 0;
1057 	phdyn = NULL;
1058 	while (phdr < phlimit) {
1059 		switch (phdr->p_type) {
1060 		case PT_LOAD:
1061 			if (nsegs == MAXSEGS) {
1062 				link_elf_error(filename, "Too many sections");
1063 				error = ENOEXEC;
1064 				goto out;
1065 			}
1066 			/*
1067 			 * XXX: We just trust they come in right order ??
1068 			 */
1069 			segs[nsegs] = phdr;
1070 			++nsegs;
1071 			break;
1072 
1073 		case PT_DYNAMIC:
1074 			phdyn = phdr;
1075 			break;
1076 
1077 		case PT_INTERP:
1078 			error = ENOSYS;
1079 			goto out;
1080 		}
1081 
1082 		++phdr;
1083 	}
1084 	if (phdyn == NULL) {
1085 		link_elf_error(filename, "Object is not dynamically-linked");
1086 		error = ENOEXEC;
1087 		goto out;
1088 	}
1089 	if (nsegs == 0) {
1090 		link_elf_error(filename, "No sections");
1091 		error = ENOEXEC;
1092 		goto out;
1093 	}
1094 
1095 	/*
1096 	 * Allocate the entire address space of the object, to stake
1097 	 * out our contiguous region, and to establish the base
1098 	 * address for relocation.
1099 	 */
1100 	base_vaddr = trunc_page(segs[0]->p_vaddr);
1101 	base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1102 	    segs[nsegs - 1]->p_memsz);
1103 	mapsize = base_vlimit - base_vaddr;
1104 
1105 	lf = linker_make_file(filename, &link_elf_class);
1106 	if (lf == NULL) {
1107 		error = ENOMEM;
1108 		goto out;
1109 	}
1110 
1111 	ef = (elf_file_t) lf;
1112 #ifdef SPARSE_MAPPING
1113 	ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1114 	    0, thread0.td_ucred);
1115 	if (ef->object == NULL) {
1116 		error = ENOMEM;
1117 		goto out;
1118 	}
1119 #ifdef __amd64__
1120 	mapbase = (caddr_t)KERNBASE;
1121 #else
1122 	mapbase = (caddr_t)vm_map_min(kernel_map);
1123 #endif
1124 	/*
1125 	 * Mapping protections are downgraded after relocation processing.
1126 	 */
1127 	error = vm_map_find(kernel_map, ef->object, 0,
1128 	    (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1129 	    VM_PROT_ALL, VM_PROT_ALL, 0);
1130 	if (error != 0) {
1131 		vm_object_deallocate(ef->object);
1132 		ef->object = NULL;
1133 		goto out;
1134 	}
1135 #else
1136 	mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1137 #endif
1138 	ef->address = mapbase;
1139 
1140 	/*
1141 	 * Read the text and data sections and zero the bss.
1142 	 */
1143 	for (i = 0; i < nsegs; i++) {
1144 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1145 
1146 #ifdef SPARSE_MAPPING
1147 		/*
1148 		 * Consecutive segments may have different mapping permissions,
1149 		 * so be strict and verify that their mappings do not overlap.
1150 		 */
1151 		if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1152 			error = EINVAL;
1153 			goto out;
1154 		}
1155 
1156 		error = vm_map_wire(kernel_map,
1157 		    (vm_offset_t)segbase,
1158 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1159 		    VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1160 		if (error != KERN_SUCCESS) {
1161 			error = ENOMEM;
1162 			goto out;
1163 		}
1164 #endif
1165 
1166 		error = vn_rdwr(UIO_READ, nd.ni_vp,
1167 		    segbase, segs[i]->p_filesz, segs[i]->p_offset,
1168 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1169 		    &resid, td);
1170 		if (error != 0)
1171 			goto out;
1172 		bzero(segbase + segs[i]->p_filesz,
1173 		    segs[i]->p_memsz - segs[i]->p_filesz);
1174 	}
1175 
1176 #ifdef GPROF
1177 	/* Update profiling information with the new text segment. */
1178 	mtx_lock(&Giant);
1179 	kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1180 	    segs[0]->p_memsz));
1181 	mtx_unlock(&Giant);
1182 #endif
1183 
1184 	ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1185 
1186 	lf->address = ef->address;
1187 	lf->size = mapsize;
1188 
1189 	error = parse_dynamic(ef);
1190 	if (error != 0)
1191 		goto out;
1192 	error = parse_dpcpu(ef);
1193 	if (error != 0)
1194 		goto out;
1195 #ifdef VIMAGE
1196 	error = parse_vnet(ef);
1197 	if (error != 0)
1198 		goto out;
1199 #endif
1200 	link_elf_reloc_local(lf);
1201 
1202 	VOP_UNLOCK(nd.ni_vp);
1203 	error = linker_load_dependencies(lf);
1204 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1205 	if (error != 0)
1206 		goto out;
1207 	error = relocate_file(ef);
1208 	if (error != 0)
1209 		goto out;
1210 
1211 #ifdef SPARSE_MAPPING
1212 	/*
1213 	 * Downgrade permissions on text segment mappings now that relocation
1214 	 * processing is complete.  Restrict permissions on read-only segments.
1215 	 */
1216 	for (i = 0; i < nsegs; i++) {
1217 		vm_prot_t prot;
1218 
1219 		if (segs[i]->p_type != PT_LOAD)
1220 			continue;
1221 
1222 		prot = VM_PROT_READ;
1223 		if ((segs[i]->p_flags & PF_W) != 0)
1224 			prot |= VM_PROT_WRITE;
1225 		if ((segs[i]->p_flags & PF_X) != 0)
1226 			prot |= VM_PROT_EXECUTE;
1227 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1228 		error = vm_map_protect(kernel_map,
1229 		    (vm_offset_t)segbase,
1230 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1231 		    prot, 0, VM_MAP_PROTECT_SET_PROT);
1232 		if (error != KERN_SUCCESS) {
1233 			error = ENOMEM;
1234 			goto out;
1235 		}
1236 	}
1237 #endif
1238 
1239 	/*
1240 	 * Try and load the symbol table if it's present.  (you can
1241 	 * strip it!)
1242 	 */
1243 	nbytes = hdr->e_shnum * hdr->e_shentsize;
1244 	if (nbytes == 0 || hdr->e_shoff == 0)
1245 		goto nosyms;
1246 	shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1247 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1248 	    (caddr_t)shdr, nbytes, hdr->e_shoff,
1249 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1250 	    &resid, td);
1251 	if (error != 0)
1252 		goto out;
1253 
1254 	/* Read section string table */
1255 	shstrindex = hdr->e_shstrndx;
1256 	if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1257 	    shdr[shstrindex].sh_size != 0) {
1258 		nbytes = shdr[shstrindex].sh_size;
1259 		shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1260 		error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1261 		    shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1262 		    td->td_ucred, NOCRED, &resid, td);
1263 		if (error)
1264 			goto out;
1265 	}
1266 
1267 	symtabindex = -1;
1268 	symstrindex = -1;
1269 	for (i = 0; i < hdr->e_shnum; i++) {
1270 		if (shdr[i].sh_type == SHT_SYMTAB) {
1271 			symtabindex = i;
1272 			symstrindex = shdr[i].sh_link;
1273 		} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1274 		    strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1275 			/* Record relocated address and size of .ctors. */
1276 			lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1277 			lf->ctors_size = shdr[i].sh_size;
1278 		}
1279 	}
1280 	if (symtabindex < 0 || symstrindex < 0)
1281 		goto nosyms;
1282 
1283 	symcnt = shdr[symtabindex].sh_size;
1284 	ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1285 	strcnt = shdr[symstrindex].sh_size;
1286 	ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1287 
1288 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1289 	    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1290 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1291 	    &resid, td);
1292 	if (error != 0)
1293 		goto out;
1294 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1295 	    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1296 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1297 	    &resid, td);
1298 	if (error != 0)
1299 		goto out;
1300 
1301 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1302 	ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1303 	ef->ddbstrcnt = strcnt;
1304 	ef->ddbstrtab = ef->strbase;
1305 
1306 nosyms:
1307 
1308 #ifdef __arm__
1309 	link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1310 #endif
1311 
1312 	error = link_elf_link_common_finish(lf);
1313 	if (error != 0)
1314 		goto out;
1315 
1316 	*result = lf;
1317 
1318 out:
1319 	VOP_UNLOCK(nd.ni_vp);
1320 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1321 	if (error != 0 && lf != NULL)
1322 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1323 	free(shdr, M_LINKER);
1324 	free(firstpage, M_LINKER);
1325 	free(shstrs, M_LINKER);
1326 
1327 	return (error);
1328 }
1329 
1330 Elf_Addr
elf_relocaddr(linker_file_t lf,Elf_Addr x)1331 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1332 {
1333 	elf_file_t ef;
1334 
1335 	KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1336 	    ("elf_relocaddr: unexpected linker file %p", lf));
1337 
1338 	ef = (elf_file_t)lf;
1339 	if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1340 		return ((x - ef->pcpu_start) + ef->pcpu_base);
1341 #ifdef VIMAGE
1342 	if (x >= ef->vnet_start && x < ef->vnet_stop)
1343 		return ((x - ef->vnet_start) + ef->vnet_base);
1344 #endif
1345 	return (x);
1346 }
1347 
1348 static void
link_elf_unload_file(linker_file_t file)1349 link_elf_unload_file(linker_file_t file)
1350 {
1351 	elf_file_t ef = (elf_file_t) file;
1352 
1353 	if (ef->pcpu_base != 0) {
1354 		dpcpu_free((void *)ef->pcpu_base,
1355 		    ef->pcpu_stop - ef->pcpu_start);
1356 		elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1357 	}
1358 #ifdef VIMAGE
1359 	if (ef->vnet_base != 0) {
1360 		vnet_data_free((void *)ef->vnet_base,
1361 		    ef->vnet_stop - ef->vnet_start);
1362 		elf_set_delete(&set_vnet_list, ef->vnet_start);
1363 	}
1364 #endif
1365 #ifdef GDB
1366 	if (ef->gdb.l_ld != NULL) {
1367 		GDB_STATE(RT_DELETE);
1368 		free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1369 		link_elf_delete_gdb(&ef->gdb);
1370 		GDB_STATE(RT_CONSISTENT);
1371 	}
1372 #endif
1373 
1374 	/* Notify MD code that a module is being unloaded. */
1375 	elf_cpu_unload_file(file);
1376 
1377 	if (ef->preloaded) {
1378 		link_elf_unload_preload(file);
1379 		return;
1380 	}
1381 
1382 #ifdef SPARSE_MAPPING
1383 	if (ef->object != NULL) {
1384 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1385 		    (vm_offset_t) ef->address
1386 		    + (ef->object->size << PAGE_SHIFT));
1387 	}
1388 #else
1389 	free(ef->address, M_LINKER);
1390 #endif
1391 	free(ef->symbase, M_LINKER);
1392 	free(ef->strbase, M_LINKER);
1393 	free(ef->ctftab, M_LINKER);
1394 	free(ef->ctfoff, M_LINKER);
1395 	free(ef->typoff, M_LINKER);
1396 }
1397 
1398 static void
link_elf_unload_preload(linker_file_t file)1399 link_elf_unload_preload(linker_file_t file)
1400 {
1401 
1402 	if (file->pathname != NULL)
1403 		preload_delete_name(file->pathname);
1404 }
1405 
1406 static const char *
symbol_name(elf_file_t ef,Elf_Size r_info)1407 symbol_name(elf_file_t ef, Elf_Size r_info)
1408 {
1409 	const Elf_Sym *ref;
1410 
1411 	if (ELF_R_SYM(r_info)) {
1412 		ref = ef->symtab + ELF_R_SYM(r_info);
1413 		return (ef->strtab + ref->st_name);
1414 	}
1415 	return (NULL);
1416 }
1417 
1418 static int
symbol_type(elf_file_t ef,Elf_Size r_info)1419 symbol_type(elf_file_t ef, Elf_Size r_info)
1420 {
1421 	const Elf_Sym *ref;
1422 
1423 	if (ELF_R_SYM(r_info)) {
1424 		ref = ef->symtab + ELF_R_SYM(r_info);
1425 		return (ELF_ST_TYPE(ref->st_info));
1426 	}
1427 	return (STT_NOTYPE);
1428 }
1429 
1430 static int
relocate_file1(elf_file_t ef,elf_lookup_fn lookup,elf_reloc_fn reloc,bool ifuncs)1431 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1432     bool ifuncs)
1433 {
1434 	const Elf_Rel *rel;
1435 	const Elf_Rela *rela;
1436 	const char *symname;
1437 
1438 #define	APPLY_RELOCS(iter, tbl, tblsize, type) do {			\
1439 	for ((iter) = (tbl); (iter) != NULL &&				\
1440 	    (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) {	\
1441 		if ((symbol_type(ef, (iter)->r_info) ==			\
1442 		    STT_GNU_IFUNC ||					\
1443 		    elf_is_ifunc_reloc((iter)->r_info)) != ifuncs)	\
1444 			continue;					\
1445 		if (reloc(&ef->lf, (Elf_Addr)ef->address,		\
1446 		    (iter), (type), lookup)) {				\
1447 			symname = symbol_name(ef, (iter)->r_info);	\
1448 			printf("link_elf: symbol %s undefined\n",	\
1449 			    symname);					\
1450 			return (ENOENT);				\
1451 		}							\
1452 	}								\
1453 } while (0)
1454 
1455 	APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1456 	APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1457 	APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1458 	APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1459 
1460 #undef APPLY_RELOCS
1461 
1462 	return (0);
1463 }
1464 
1465 static int
relocate_file(elf_file_t ef)1466 relocate_file(elf_file_t ef)
1467 {
1468 	int error;
1469 
1470 	error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1471 	if (error == 0)
1472 		error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1473 	return (error);
1474 }
1475 
1476 /*
1477  * Hash function for symbol table lookup.  Don't even think about changing
1478  * this.  It is specified by the System V ABI.
1479  */
1480 static unsigned long
elf_hash(const char * name)1481 elf_hash(const char *name)
1482 {
1483 	const unsigned char *p = (const unsigned char *) name;
1484 	unsigned long h = 0;
1485 	unsigned long g;
1486 
1487 	while (*p != '\0') {
1488 		h = (h << 4) + *p++;
1489 		if ((g = h & 0xf0000000) != 0)
1490 			h ^= g >> 24;
1491 		h &= ~g;
1492 	}
1493 	return (h);
1494 }
1495 
1496 static int
link_elf_lookup_symbol(linker_file_t lf,const char * name,c_linker_sym_t * sym)1497 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1498 {
1499 	elf_file_t ef = (elf_file_t) lf;
1500 	unsigned long symnum;
1501 	const Elf_Sym* symp;
1502 	const char *strp;
1503 	unsigned long hash;
1504 	int i;
1505 
1506 	/* If we don't have a hash, bail. */
1507 	if (ef->buckets == NULL || ef->nbuckets == 0) {
1508 		printf("link_elf_lookup_symbol: missing symbol hash table\n");
1509 		return (ENOENT);
1510 	}
1511 
1512 	/* First, search hashed global symbols */
1513 	hash = elf_hash(name);
1514 	symnum = ef->buckets[hash % ef->nbuckets];
1515 
1516 	while (symnum != STN_UNDEF) {
1517 		if (symnum >= ef->nchains) {
1518 			printf("%s: corrupt symbol table\n", __func__);
1519 			return (ENOENT);
1520 		}
1521 
1522 		symp = ef->symtab + symnum;
1523 		if (symp->st_name == 0) {
1524 			printf("%s: corrupt symbol table\n", __func__);
1525 			return (ENOENT);
1526 		}
1527 
1528 		strp = ef->strtab + symp->st_name;
1529 
1530 		if (strcmp(name, strp) == 0) {
1531 			if (symp->st_shndx != SHN_UNDEF ||
1532 			    (symp->st_value != 0 &&
1533 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1534 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1535 				*sym = (c_linker_sym_t) symp;
1536 				return (0);
1537 			}
1538 			return (ENOENT);
1539 		}
1540 
1541 		symnum = ef->chains[symnum];
1542 	}
1543 
1544 	/* If we have not found it, look at the full table (if loaded) */
1545 	if (ef->symtab == ef->ddbsymtab)
1546 		return (ENOENT);
1547 
1548 	/* Exhaustive search */
1549 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1550 		strp = ef->ddbstrtab + symp->st_name;
1551 		if (strcmp(name, strp) == 0) {
1552 			if (symp->st_shndx != SHN_UNDEF ||
1553 			    (symp->st_value != 0 &&
1554 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1555 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1556 				*sym = (c_linker_sym_t) symp;
1557 				return (0);
1558 			}
1559 			return (ENOENT);
1560 		}
1561 	}
1562 
1563 	return (ENOENT);
1564 }
1565 
1566 static int
link_elf_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1567 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1568     linker_symval_t *symval)
1569 {
1570 	elf_file_t ef;
1571 	const Elf_Sym *es;
1572 	caddr_t val;
1573 
1574 	ef = (elf_file_t)lf;
1575 	es = (const Elf_Sym *)sym;
1576 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1577 		symval->name = ef->strtab + es->st_name;
1578 		val = (caddr_t)ef->address + es->st_value;
1579 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1580 			val = ((caddr_t (*)(void))val)();
1581 		symval->value = val;
1582 		symval->size = es->st_size;
1583 		return (0);
1584 	}
1585 	if (ef->symtab == ef->ddbsymtab)
1586 		return (ENOENT);
1587 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1588 		symval->name = ef->ddbstrtab + es->st_name;
1589 		val = (caddr_t)ef->address + es->st_value;
1590 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1591 			val = ((caddr_t (*)(void))val)();
1592 		symval->value = val;
1593 		symval->size = es->st_size;
1594 		return (0);
1595 	}
1596 	return (ENOENT);
1597 }
1598 
1599 static int
link_elf_search_symbol(linker_file_t lf,caddr_t value,c_linker_sym_t * sym,long * diffp)1600 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1601     c_linker_sym_t *sym, long *diffp)
1602 {
1603 	elf_file_t ef = (elf_file_t) lf;
1604 	u_long off = (uintptr_t) (void *) value;
1605 	u_long diff = off;
1606 	u_long st_value;
1607 	const Elf_Sym* es;
1608 	const Elf_Sym* best = NULL;
1609 	int i;
1610 
1611 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1612 		if (es->st_name == 0)
1613 			continue;
1614 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1615 		if (off >= st_value) {
1616 			if (off - st_value < diff) {
1617 				diff = off - st_value;
1618 				best = es;
1619 				if (diff == 0)
1620 					break;
1621 			} else if (off - st_value == diff) {
1622 				best = es;
1623 			}
1624 		}
1625 	}
1626 	if (best == NULL)
1627 		*diffp = off;
1628 	else
1629 		*diffp = diff;
1630 	*sym = (c_linker_sym_t) best;
1631 
1632 	return (0);
1633 }
1634 
1635 /*
1636  * Look up a linker set on an ELF system.
1637  */
1638 static int
link_elf_lookup_set(linker_file_t lf,const char * name,void *** startp,void *** stopp,int * countp)1639 link_elf_lookup_set(linker_file_t lf, const char *name,
1640     void ***startp, void ***stopp, int *countp)
1641 {
1642 	c_linker_sym_t sym;
1643 	linker_symval_t symval;
1644 	char *setsym;
1645 	void **start, **stop;
1646 	int len, error = 0, count;
1647 
1648 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1649 	setsym = malloc(len, M_LINKER, M_WAITOK);
1650 
1651 	/* get address of first entry */
1652 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1653 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1654 	if (error != 0)
1655 		goto out;
1656 	link_elf_symbol_values(lf, sym, &symval);
1657 	if (symval.value == 0) {
1658 		error = ESRCH;
1659 		goto out;
1660 	}
1661 	start = (void **)symval.value;
1662 
1663 	/* get address of last entry */
1664 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1665 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1666 	if (error != 0)
1667 		goto out;
1668 	link_elf_symbol_values(lf, sym, &symval);
1669 	if (symval.value == 0) {
1670 		error = ESRCH;
1671 		goto out;
1672 	}
1673 	stop = (void **)symval.value;
1674 
1675 	/* and the number of entries */
1676 	count = stop - start;
1677 
1678 	/* and copy out */
1679 	if (startp != NULL)
1680 		*startp = start;
1681 	if (stopp != NULL)
1682 		*stopp = stop;
1683 	if (countp != NULL)
1684 		*countp = count;
1685 
1686 out:
1687 	free(setsym, M_LINKER);
1688 	return (error);
1689 }
1690 
1691 static int
link_elf_each_function_name(linker_file_t file,int (* callback)(const char *,void *),void * opaque)1692 link_elf_each_function_name(linker_file_t file,
1693   int (*callback)(const char *, void *), void *opaque)
1694 {
1695 	elf_file_t ef = (elf_file_t)file;
1696 	const Elf_Sym *symp;
1697 	int i, error;
1698 
1699 	/* Exhaustive search */
1700 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1701 		if (symp->st_value != 0 &&
1702 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1703 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1704 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1705 			if (error != 0)
1706 				return (error);
1707 		}
1708 	}
1709 	return (0);
1710 }
1711 
1712 static int
link_elf_each_function_nameval(linker_file_t file,linker_function_nameval_callback_t callback,void * opaque)1713 link_elf_each_function_nameval(linker_file_t file,
1714     linker_function_nameval_callback_t callback, void *opaque)
1715 {
1716 	linker_symval_t symval;
1717 	elf_file_t ef = (elf_file_t)file;
1718 	const Elf_Sym* symp;
1719 	int i, error;
1720 
1721 	/* Exhaustive search */
1722 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1723 		if (symp->st_value != 0 &&
1724 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1725 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1726 			error = link_elf_symbol_values(file,
1727 			    (c_linker_sym_t) symp, &symval);
1728 			if (error != 0)
1729 				return (error);
1730 			error = callback(file, i, &symval, opaque);
1731 			if (error != 0)
1732 				return (error);
1733 		}
1734 	}
1735 	return (0);
1736 }
1737 
1738 const Elf_Sym *
elf_get_sym(linker_file_t lf,Elf_Size symidx)1739 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1740 {
1741 	elf_file_t ef = (elf_file_t)lf;
1742 
1743 	if (symidx >= ef->nchains)
1744 		return (NULL);
1745 	return (ef->symtab + symidx);
1746 }
1747 
1748 const char *
elf_get_symname(linker_file_t lf,Elf_Size symidx)1749 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1750 {
1751 	elf_file_t ef = (elf_file_t)lf;
1752 	const Elf_Sym *sym;
1753 
1754 	if (symidx >= ef->nchains)
1755 		return (NULL);
1756 	sym = ef->symtab + symidx;
1757 	return (ef->strtab + sym->st_name);
1758 }
1759 
1760 /*
1761  * Symbol lookup function that can be used when the symbol index is known (ie
1762  * in relocations). It uses the symbol index instead of doing a fully fledged
1763  * hash table based lookup when such is valid. For example for local symbols.
1764  * This is not only more efficient, it's also more correct. It's not always
1765  * the case that the symbol can be found through the hash table.
1766  */
1767 static int
elf_lookup(linker_file_t lf,Elf_Size symidx,int deps,Elf_Addr * res)1768 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1769 {
1770 	elf_file_t ef = (elf_file_t)lf;
1771 	const Elf_Sym *sym;
1772 	const char *symbol;
1773 	Elf_Addr addr, start, base;
1774 
1775 	/* Don't even try to lookup the symbol if the index is bogus. */
1776 	if (symidx >= ef->nchains) {
1777 		*res = 0;
1778 		return (EINVAL);
1779 	}
1780 
1781 	sym = ef->symtab + symidx;
1782 
1783 	/*
1784 	 * Don't do a full lookup when the symbol is local. It may even
1785 	 * fail because it may not be found through the hash table.
1786 	 */
1787 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1788 		/* Force lookup failure when we have an insanity. */
1789 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1790 			*res = 0;
1791 			return (EINVAL);
1792 		}
1793 		*res = ((Elf_Addr)ef->address + sym->st_value);
1794 		return (0);
1795 	}
1796 
1797 	/*
1798 	 * XXX we can avoid doing a hash table based lookup for global
1799 	 * symbols as well. This however is not always valid, so we'll
1800 	 * just do it the hard way for now. Performance tweaks can
1801 	 * always be added.
1802 	 */
1803 
1804 	symbol = ef->strtab + sym->st_name;
1805 
1806 	/* Force a lookup failure if the symbol name is bogus. */
1807 	if (*symbol == 0) {
1808 		*res = 0;
1809 		return (EINVAL);
1810 	}
1811 
1812 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1813 	if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1814 		*res = 0;
1815 		return (EINVAL);
1816 	}
1817 
1818 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1819 		addr = addr - start + base;
1820 #ifdef VIMAGE
1821 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1822 		addr = addr - start + base;
1823 #endif
1824 	*res = addr;
1825 	return (0);
1826 }
1827 
1828 static void
link_elf_reloc_local(linker_file_t lf)1829 link_elf_reloc_local(linker_file_t lf)
1830 {
1831 	const Elf_Rel *rellim;
1832 	const Elf_Rel *rel;
1833 	const Elf_Rela *relalim;
1834 	const Elf_Rela *rela;
1835 	elf_file_t ef = (elf_file_t)lf;
1836 
1837 	/* Perform relocations without addend if there are any: */
1838 	if ((rel = ef->rel) != NULL) {
1839 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1840 		while (rel < rellim) {
1841 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1842 			    ELF_RELOC_REL, elf_lookup);
1843 			rel++;
1844 		}
1845 	}
1846 
1847 	/* Perform relocations with addend if there are any: */
1848 	if ((rela = ef->rela) != NULL) {
1849 		relalim = (const Elf_Rela *)
1850 		    ((const char *)ef->rela + ef->relasize);
1851 		while (rela < relalim) {
1852 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1853 			    ELF_RELOC_RELA, elf_lookup);
1854 			rela++;
1855 		}
1856 	}
1857 }
1858 
1859 static long
link_elf_symtab_get(linker_file_t lf,const Elf_Sym ** symtab)1860 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1861 {
1862 	elf_file_t ef = (elf_file_t)lf;
1863 
1864 	*symtab = ef->ddbsymtab;
1865 
1866 	if (*symtab == NULL)
1867 		return (0);
1868 
1869 	return (ef->ddbsymcnt);
1870 }
1871 
1872 static long
link_elf_strtab_get(linker_file_t lf,caddr_t * strtab)1873 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1874 {
1875 	elf_file_t ef = (elf_file_t)lf;
1876 
1877 	*strtab = ef->ddbstrtab;
1878 
1879 	if (*strtab == NULL)
1880 		return (0);
1881 
1882 	return (ef->ddbstrcnt);
1883 }
1884 
1885 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1886 /*
1887  * Use this lookup routine when performing relocations early during boot.
1888  * The generic lookup routine depends on kobj, which is not initialized
1889  * at that point.
1890  */
1891 static int
elf_lookup_ifunc(linker_file_t lf,Elf_Size symidx,int deps __unused,Elf_Addr * res)1892 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1893     Elf_Addr *res)
1894 {
1895 	elf_file_t ef;
1896 	const Elf_Sym *symp;
1897 	caddr_t val;
1898 
1899 	ef = (elf_file_t)lf;
1900 	symp = ef->symtab + symidx;
1901 	if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1902 		val = (caddr_t)ef->address + symp->st_value;
1903 		*res = ((Elf_Addr (*)(void))val)();
1904 		return (0);
1905 	}
1906 	return (ENOENT);
1907 }
1908 
1909 void
link_elf_ireloc(caddr_t kmdp)1910 link_elf_ireloc(caddr_t kmdp)
1911 {
1912 	struct elf_file eff;
1913 	elf_file_t ef;
1914 
1915 	ef = &eff;
1916 
1917 	bzero_early(ef, sizeof(*ef));
1918 
1919 	ef->modptr = kmdp;
1920 	ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1921 
1922 #ifdef RELOCATABLE_KERNEL
1923 	ef->address = (caddr_t) (__startkernel - KERNBASE);
1924 #else
1925 	ef->address = 0;
1926 #endif
1927 	parse_dynamic(ef);
1928 
1929 	link_elf_preload_parse_symbols(ef);
1930 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1931 }
1932 
1933 #if defined(__aarch64__) || defined(__amd64__)
1934 void
link_elf_late_ireloc(void)1935 link_elf_late_ireloc(void)
1936 {
1937 	elf_file_t ef;
1938 
1939 	KASSERT(linker_kernel_file != NULL,
1940 	    ("link_elf_late_ireloc: No kernel linker file found"));
1941 	ef = (elf_file_t)linker_kernel_file;
1942 
1943 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);
1944 }
1945 #endif
1946 #endif
1947