xref: /freebsd/sys/kern/link_elf.c (revision 7ef5c19b)
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 modptr, 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 = NULL;
461 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
462 	if (modptr == NULL)
463 		modptr = preload_search_by_type("elf kernel");
464 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
465 	if (modname == NULL)
466 		modname = "kernel";
467 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
468 	if (linker_kernel_file == NULL)
469 		panic("%s: Can't create linker structures for kernel",
470 		    __func__);
471 
472 	ef = (elf_file_t) linker_kernel_file;
473 	ef->preloaded = 1;
474 #ifdef RELOCATABLE_KERNEL
475 	/* Compute relative displacement */
476 	ef->address = (caddr_t) (__startkernel - KERNBASE);
477 #else
478 	ef->address = 0;
479 #endif
480 #ifdef SPARSE_MAPPING
481 	ef->object = NULL;
482 #endif
483 	ef->dynamic = dp;
484 
485 	if (dp != NULL)
486 		parse_dynamic(ef);
487 #ifdef RELOCATABLE_KERNEL
488 	linker_kernel_file->address = (caddr_t)__startkernel;
489 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
490 	kern_relbase = (unsigned long)__startkernel;
491 #else
492 	linker_kernel_file->address += KERNBASE;
493 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
494 #endif
495 
496 	if (modptr != NULL) {
497 		ef->modptr = modptr;
498 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
499 		if (baseptr != NULL)
500 			linker_kernel_file->address = *(caddr_t *)baseptr;
501 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
502 		if (sizeptr != NULL)
503 			linker_kernel_file->size = *(size_t *)sizeptr;
504 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
505 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
506 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
507 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
508 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
509 			linker_kernel_file->ctors_addr = ef->address +
510 			    *ctors_addrp;
511 			linker_kernel_file->ctors_size = *ctors_sizep;
512 		}
513 	}
514 	(void)link_elf_preload_parse_symbols(ef);
515 
516 #ifdef GDB
517 	r_debug.r_map = NULL;
518 	r_debug.r_brk = r_debug_state;
519 	r_debug.r_state = RT_CONSISTENT;
520 #endif
521 
522 	(void)link_elf_link_common_finish(linker_kernel_file);
523 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
524 	TAILQ_INIT(&set_pcpu_list);
525 #ifdef VIMAGE
526 	TAILQ_INIT(&set_vnet_list);
527 	vnet_save_init((void *)VNET_START, VNET_STOP - VNET_START);
528 #endif
529 }
530 
531 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
532 
533 static int
link_elf_preload_parse_symbols(elf_file_t ef)534 link_elf_preload_parse_symbols(elf_file_t ef)
535 {
536 	caddr_t pointer;
537 	caddr_t ssym, esym, base;
538 	caddr_t strtab;
539 	int strcnt;
540 	Elf_Sym *symtab;
541 	int symcnt;
542 
543 	if (ef->modptr == NULL)
544 		return (0);
545 	pointer = preload_search_info(ef->modptr,
546 	    MODINFO_METADATA | MODINFOMD_SSYM);
547 	if (pointer == NULL)
548 		return (0);
549 	ssym = *(caddr_t *)pointer;
550 	pointer = preload_search_info(ef->modptr,
551 	    MODINFO_METADATA | MODINFOMD_ESYM);
552 	if (pointer == NULL)
553 		return (0);
554 	esym = *(caddr_t *)pointer;
555 
556 	base = ssym;
557 
558 	symcnt = *(long *)base;
559 	base += sizeof(long);
560 	symtab = (Elf_Sym *)base;
561 	base += roundup(symcnt, sizeof(long));
562 
563 	if (base > esym || base < ssym) {
564 		printf("Symbols are corrupt!\n");
565 		return (EINVAL);
566 	}
567 
568 	strcnt = *(long *)base;
569 	base += sizeof(long);
570 	strtab = base;
571 	base += roundup(strcnt, sizeof(long));
572 
573 	if (base > esym || base < ssym) {
574 		printf("Symbols are corrupt!\n");
575 		return (EINVAL);
576 	}
577 
578 	ef->ddbsymtab = symtab;
579 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
580 	ef->ddbstrtab = strtab;
581 	ef->ddbstrcnt = strcnt;
582 
583 	return (0);
584 }
585 
586 static int
parse_dynamic(elf_file_t ef)587 parse_dynamic(elf_file_t ef)
588 {
589 	Elf_Dyn *dp;
590 	int plttype = DT_REL;
591 
592 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
593 		switch (dp->d_tag) {
594 		case DT_HASH:
595 		{
596 			/* From src/libexec/rtld-elf/rtld.c */
597 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
598 			    (ef->address + dp->d_un.d_ptr);
599 			ef->nbuckets = hashtab[0];
600 			ef->nchains = hashtab[1];
601 			ef->buckets = hashtab + 2;
602 			ef->chains = ef->buckets + ef->nbuckets;
603 			break;
604 		}
605 		case DT_STRTAB:
606 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
607 			break;
608 		case DT_STRSZ:
609 			ef->strsz = dp->d_un.d_val;
610 			break;
611 		case DT_SYMTAB:
612 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
613 			break;
614 		case DT_SYMENT:
615 			if (dp->d_un.d_val != sizeof(Elf_Sym))
616 				return (ENOEXEC);
617 			break;
618 		case DT_PLTGOT:
619 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
620 			break;
621 		case DT_REL:
622 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
623 			break;
624 		case DT_RELSZ:
625 			ef->relsize = dp->d_un.d_val;
626 			break;
627 		case DT_RELENT:
628 			if (dp->d_un.d_val != sizeof(Elf_Rel))
629 				return (ENOEXEC);
630 			break;
631 		case DT_JMPREL:
632 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
633 			break;
634 		case DT_PLTRELSZ:
635 			ef->pltrelsize = dp->d_un.d_val;
636 			break;
637 		case DT_RELA:
638 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
639 			break;
640 		case DT_RELASZ:
641 			ef->relasize = dp->d_un.d_val;
642 			break;
643 		case DT_RELAENT:
644 			if (dp->d_un.d_val != sizeof(Elf_Rela))
645 				return (ENOEXEC);
646 			break;
647 		case DT_PLTREL:
648 			plttype = dp->d_un.d_val;
649 			if (plttype != DT_REL && plttype != DT_RELA)
650 				return (ENOEXEC);
651 			break;
652 #ifdef GDB
653 		case DT_DEBUG:
654 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
655 			break;
656 #endif
657 		}
658 	}
659 
660 	if (plttype == DT_RELA) {
661 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
662 		ef->pltrel = NULL;
663 		ef->pltrelasize = ef->pltrelsize;
664 		ef->pltrelsize = 0;
665 	}
666 
667 	ef->ddbsymtab = ef->symtab;
668 	ef->ddbsymcnt = ef->nchains;
669 	ef->ddbstrtab = ef->strtab;
670 	ef->ddbstrcnt = ef->strsz;
671 
672 	return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
673 }
674 
675 #define	LS_PADDING	0x90909090
676 static int
parse_dpcpu(elf_file_t ef)677 parse_dpcpu(elf_file_t ef)
678 {
679 	int error, size;
680 #if defined(__i386__)
681 	uint32_t pad;
682 #endif
683 
684 	ef->pcpu_start = 0;
685 	ef->pcpu_stop = 0;
686 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
687 	    (void ***)&ef->pcpu_stop, NULL);
688 	/* Error just means there is no pcpu set to relocate. */
689 	if (error != 0)
690 		return (0);
691 	size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
692 	/* Empty set? */
693 	if (size < 1)
694 		return (0);
695 #if defined(__i386__)
696 	/* In case we do find __start/stop_set_ symbols double-check. */
697 	if (size < 4) {
698 		uprintf("Kernel module '%s' must be recompiled with "
699 		    "linker script\n", ef->lf.pathname);
700 		return (ENOEXEC);
701 	}
702 
703 	/* Padding from linker-script correct? */
704 	pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
705 	if (pad != LS_PADDING) {
706 		uprintf("Kernel module '%s' must be recompiled with "
707 		    "linker script, invalid padding %#04x (%#04x)\n",
708 		    ef->lf.pathname, pad, LS_PADDING);
709 		return (ENOEXEC);
710 	}
711 	/* If we only have valid padding, nothing to do. */
712 	if (size == 4)
713 		return (0);
714 #endif
715 	/*
716 	 * Allocate space in the primary pcpu area.  Copy in our
717 	 * initialization from the data section and then initialize
718 	 * all per-cpu storage from that.
719 	 */
720 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
721 	if (ef->pcpu_base == 0) {
722 		printf("%s: pcpu module space is out of space; "
723 		    "cannot allocate %d for %s\n",
724 		    __func__, size, ef->lf.pathname);
725 		return (ENOSPC);
726 	}
727 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
728 	dpcpu_copy((void *)ef->pcpu_base, size);
729 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
730 	    ef->pcpu_base);
731 
732 	return (0);
733 }
734 
735 #ifdef VIMAGE
736 static int
parse_vnet(elf_file_t ef)737 parse_vnet(elf_file_t ef)
738 {
739 	int error, size;
740 #if defined(__i386__)
741 	uint32_t pad;
742 #endif
743 
744 	ef->vnet_start = 0;
745 	ef->vnet_stop = 0;
746 	ef->vnet_base = 0;
747 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
748 	    (void ***)&ef->vnet_stop, NULL);
749 	/* Error just means there is no vnet data set to relocate. */
750 	if (error != 0)
751 		return (0);
752 	size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
753 	/* Empty set? */
754 	if (size < 1)
755 		return (0);
756 #if defined(__i386__)
757 	/* In case we do find __start/stop_set_ symbols double-check. */
758 	if (size < 4) {
759 		uprintf("Kernel module '%s' must be recompiled with "
760 		    "linker script\n", ef->lf.pathname);
761 		return (ENOEXEC);
762 	}
763 
764 	/* Padding from linker-script correct? */
765 	pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
766 	if (pad != LS_PADDING) {
767 		uprintf("Kernel module '%s' must be recompiled with "
768 		    "linker script, invalid padding %#04x (%#04x)\n",
769 		    ef->lf.pathname, pad, LS_PADDING);
770 		return (ENOEXEC);
771 	}
772 	/* If we only have valid padding, nothing to do. */
773 	if (size == 4)
774 		return (0);
775 #endif
776 	/*
777 	 * Allocate space in the primary vnet area.  Copy in our
778 	 * initialization from the data section and then initialize
779 	 * all per-vnet storage from that.
780 	 */
781 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
782 	if (ef->vnet_base == 0) {
783 		printf("%s: vnet module space is out of space; "
784 		    "cannot allocate %d for %s\n",
785 		    __func__, size, ef->lf.pathname);
786 		return (ENOSPC);
787 	}
788 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
789 	vnet_save_init((void *)ef->vnet_base, size);
790 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
791 	    ef->vnet_base);
792 
793 	return (0);
794 }
795 #endif
796 #undef LS_PADDING
797 
798 /*
799  * Apply the specified protection to the loadable segments of a preloaded linker
800  * file.
801  */
802 static int
preload_protect(elf_file_t ef,vm_prot_t prot)803 preload_protect(elf_file_t ef, vm_prot_t prot)
804 {
805 #if defined(__aarch64__) || defined(__amd64__)
806 	Elf_Ehdr *hdr;
807 	Elf_Phdr *phdr, *phlimit;
808 	vm_prot_t nprot;
809 	int error;
810 
811 	error = 0;
812 	hdr = (Elf_Ehdr *)ef->address;
813 	phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
814 	phlimit = phdr + hdr->e_phnum;
815 	for (; phdr < phlimit; phdr++) {
816 		if (phdr->p_type != PT_LOAD)
817 			continue;
818 
819 		nprot = prot | VM_PROT_READ;
820 		if ((phdr->p_flags & PF_W) != 0)
821 			nprot |= VM_PROT_WRITE;
822 		if ((phdr->p_flags & PF_X) != 0)
823 			nprot |= VM_PROT_EXECUTE;
824 		error = pmap_change_prot((vm_offset_t)ef->address +
825 		    phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
826 		if (error != 0)
827 			break;
828 	}
829 	return (error);
830 #else
831 	return (0);
832 #endif
833 }
834 
835 #ifdef __arm__
836 /*
837  * Locate the ARM exception/unwind table info for DDB and stack(9) use by
838  * searching for the section header that describes it.  There may be no unwind
839  * info, for example in a module containing only data.
840  */
841 static void
link_elf_locate_exidx(linker_file_t lf,Elf_Shdr * shdr,int nhdr)842 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
843 {
844 	int i;
845 
846 	for (i = 0; i < nhdr; i++) {
847 		if (shdr[i].sh_type == SHT_ARM_EXIDX) {
848 			lf->exidx_addr = shdr[i].sh_addr + lf->address;
849 			lf->exidx_size = shdr[i].sh_size;
850 			break;
851 		}
852 	}
853 }
854 
855 /*
856  * Locate the section headers metadata in a preloaded module, then use it to
857  * locate the exception/unwind table in the module.  The size of the metadata
858  * block is stored in a uint32 word immediately before the data itself, and a
859  * comment in preload_search_info() says it is safe to rely on that.
860  */
861 static void
link_elf_locate_exidx_preload(struct linker_file * lf,caddr_t modptr)862 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
863 {
864 	uint32_t *modinfo;
865 	Elf_Shdr *shdr;
866 	uint32_t  nhdr;
867 
868 	modinfo = (uint32_t *)preload_search_info(modptr,
869 	    MODINFO_METADATA | MODINFOMD_SHDR);
870 	if (modinfo != NULL) {
871 		shdr = (Elf_Shdr *)modinfo;
872 		nhdr = modinfo[-1] / sizeof(Elf_Shdr);
873 		link_elf_locate_exidx(lf, shdr, nhdr);
874 	}
875 }
876 
877 #endif /* __arm__ */
878 
879 static int
link_elf_link_preload(linker_class_t cls,const char * filename,linker_file_t * result)880 link_elf_link_preload(linker_class_t cls, const char *filename,
881     linker_file_t *result)
882 {
883 	Elf_Addr *ctors_addrp;
884 	Elf_Size *ctors_sizep;
885 	caddr_t modptr, baseptr, sizeptr, dynptr;
886 	char *type;
887 	elf_file_t ef;
888 	linker_file_t lf;
889 	int error;
890 	vm_offset_t dp;
891 
892 	/* Look to see if we have the file preloaded */
893 	modptr = preload_search_by_name(filename);
894 	if (modptr == NULL)
895 		return (ENOENT);
896 
897 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
898 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
899 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
900 	dynptr = preload_search_info(modptr,
901 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
902 	if (type == NULL ||
903 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
904 	     strcmp(type, "elf module") != 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 int
link_elf_symbol_values1(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval,bool see_local)1638 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1639     linker_symval_t *symval, bool see_local)
1640 {
1641 	elf_file_t ef;
1642 	const Elf_Sym *es;
1643 	caddr_t val;
1644 
1645 	ef = (elf_file_t)lf;
1646 	es = (const Elf_Sym *)sym;
1647 	if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1648 		if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1649 			return (ENOENT);
1650 		symval->name = ef->strtab + es->st_name;
1651 		val = (caddr_t)ef->address + es->st_value;
1652 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1653 			val = ((caddr_t (*)(void))val)();
1654 		symval->value = val;
1655 		symval->size = es->st_size;
1656 		return (0);
1657 	}
1658 	return (ENOENT);
1659 }
1660 
1661 static int
link_elf_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1662 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1663     linker_symval_t *symval)
1664 {
1665 	if (link_elf_leak_locals)
1666 		return (link_elf_debug_symbol_values(lf, sym, symval));
1667 	return (link_elf_symbol_values1(lf, sym, symval, false));
1668 }
1669 
1670 static int
link_elf_debug_symbol_values(linker_file_t lf,c_linker_sym_t sym,linker_symval_t * symval)1671 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1672     linker_symval_t *symval)
1673 {
1674 	elf_file_t ef = (elf_file_t)lf;
1675 	const Elf_Sym *es = (const Elf_Sym *)sym;
1676 	caddr_t val;
1677 
1678 	if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1679 		return (0);
1680 	if (ef->symtab == ef->ddbsymtab)
1681 		return (ENOENT);
1682 
1683 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1684 		symval->name = ef->ddbstrtab + es->st_name;
1685 		val = (caddr_t)ef->address + es->st_value;
1686 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1687 			val = ((caddr_t (*)(void))val)();
1688 		symval->value = val;
1689 		symval->size = es->st_size;
1690 		return (0);
1691 	}
1692 	return (ENOENT);
1693 }
1694 
1695 static int
link_elf_search_symbol(linker_file_t lf,caddr_t value,c_linker_sym_t * sym,long * diffp)1696 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1697     c_linker_sym_t *sym, long *diffp)
1698 {
1699 	elf_file_t ef = (elf_file_t)lf;
1700 	u_long off = (uintptr_t)(void *)value;
1701 	u_long diff = off;
1702 	u_long st_value;
1703 	const Elf_Sym *es;
1704 	const Elf_Sym *best = NULL;
1705 	int i;
1706 
1707 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1708 		if (es->st_name == 0)
1709 			continue;
1710 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1711 		if (off >= st_value) {
1712 			if (off - st_value < diff) {
1713 				diff = off - st_value;
1714 				best = es;
1715 				if (diff == 0)
1716 					break;
1717 			} else if (off - st_value == diff) {
1718 				best = es;
1719 			}
1720 		}
1721 	}
1722 	if (best == NULL)
1723 		*diffp = off;
1724 	else
1725 		*diffp = diff;
1726 	*sym = (c_linker_sym_t) best;
1727 
1728 	return (0);
1729 }
1730 
1731 /*
1732  * Look up a linker set on an ELF system.
1733  */
1734 static int
link_elf_lookup_set(linker_file_t lf,const char * name,void *** startp,void *** stopp,int * countp)1735 link_elf_lookup_set(linker_file_t lf, const char *name,
1736     void ***startp, void ***stopp, int *countp)
1737 {
1738 	c_linker_sym_t sym;
1739 	linker_symval_t symval;
1740 	char *setsym;
1741 	void **start, **stop;
1742 	int len, error = 0, count;
1743 
1744 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1745 	setsym = malloc(len, M_LINKER, M_WAITOK);
1746 
1747 	/* get address of first entry */
1748 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1749 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1750 	if (error != 0)
1751 		goto out;
1752 	link_elf_symbol_values(lf, sym, &symval);
1753 	if (symval.value == 0) {
1754 		error = ESRCH;
1755 		goto out;
1756 	}
1757 	start = (void **)symval.value;
1758 
1759 	/* get address of last entry */
1760 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1761 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1762 	if (error != 0)
1763 		goto out;
1764 	link_elf_symbol_values(lf, sym, &symval);
1765 	if (symval.value == 0) {
1766 		error = ESRCH;
1767 		goto out;
1768 	}
1769 	stop = (void **)symval.value;
1770 
1771 	/* and the number of entries */
1772 	count = stop - start;
1773 
1774 	/* and copy out */
1775 	if (startp != NULL)
1776 		*startp = start;
1777 	if (stopp != NULL)
1778 		*stopp = stop;
1779 	if (countp != NULL)
1780 		*countp = count;
1781 
1782 out:
1783 	free(setsym, M_LINKER);
1784 	return (error);
1785 }
1786 
1787 static int
link_elf_each_function_name(linker_file_t file,int (* callback)(const char *,void *),void * opaque)1788 link_elf_each_function_name(linker_file_t file,
1789   int (*callback)(const char *, void *), void *opaque)
1790 {
1791 	elf_file_t ef = (elf_file_t)file;
1792 	const Elf_Sym *symp;
1793 	int i, error;
1794 
1795 	/* Exhaustive search */
1796 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1797 		if (symp->st_value != 0 &&
1798 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1799 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1800 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1801 			if (error != 0)
1802 				return (error);
1803 		}
1804 	}
1805 	return (0);
1806 }
1807 
1808 static int
link_elf_each_function_nameval(linker_file_t file,linker_function_nameval_callback_t callback,void * opaque)1809 link_elf_each_function_nameval(linker_file_t file,
1810     linker_function_nameval_callback_t callback, void *opaque)
1811 {
1812 	linker_symval_t symval;
1813 	elf_file_t ef = (elf_file_t)file;
1814 	const Elf_Sym *symp;
1815 	int i, error;
1816 
1817 	/* Exhaustive search */
1818 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1819 		if (symp->st_value != 0 &&
1820 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1821 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1822 			error = link_elf_debug_symbol_values(file,
1823 			    (c_linker_sym_t) symp, &symval);
1824 			if (error == 0)
1825 				error = callback(file, i, &symval, opaque);
1826 			if (error != 0)
1827 				return (error);
1828 		}
1829 	}
1830 	return (0);
1831 }
1832 
1833 const Elf_Sym *
elf_get_sym(linker_file_t lf,Elf_Size symidx)1834 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1835 {
1836 	elf_file_t ef = (elf_file_t)lf;
1837 
1838 	if (symidx >= ef->nchains)
1839 		return (NULL);
1840 	return (ef->symtab + symidx);
1841 }
1842 
1843 const char *
elf_get_symname(linker_file_t lf,Elf_Size symidx)1844 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1845 {
1846 	elf_file_t ef = (elf_file_t)lf;
1847 	const Elf_Sym *sym;
1848 
1849 	if (symidx >= ef->nchains)
1850 		return (NULL);
1851 	sym = ef->symtab + symidx;
1852 	return (ef->strtab + sym->st_name);
1853 }
1854 
1855 /*
1856  * Symbol lookup function that can be used when the symbol index is known (ie
1857  * in relocations). It uses the symbol index instead of doing a fully fledged
1858  * hash table based lookup when such is valid. For example for local symbols.
1859  * This is not only more efficient, it's also more correct. It's not always
1860  * the case that the symbol can be found through the hash table.
1861  */
1862 static int
elf_lookup(linker_file_t lf,Elf_Size symidx,int deps,Elf_Addr * res)1863 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1864 {
1865 	elf_file_t ef = (elf_file_t)lf;
1866 	const Elf_Sym *sym;
1867 	const char *symbol;
1868 	Elf_Addr addr, start, base;
1869 
1870 	/* Don't even try to lookup the symbol if the index is bogus. */
1871 	if (symidx >= ef->nchains) {
1872 		*res = 0;
1873 		return (EINVAL);
1874 	}
1875 
1876 	sym = ef->symtab + symidx;
1877 
1878 	/*
1879 	 * Don't do a full lookup when the symbol is local. It may even
1880 	 * fail because it may not be found through the hash table.
1881 	 */
1882 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1883 		/* Force lookup failure when we have an insanity. */
1884 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1885 			*res = 0;
1886 			return (EINVAL);
1887 		}
1888 		*res = ((Elf_Addr)ef->address + sym->st_value);
1889 		return (0);
1890 	}
1891 
1892 	/*
1893 	 * XXX we can avoid doing a hash table based lookup for global
1894 	 * symbols as well. This however is not always valid, so we'll
1895 	 * just do it the hard way for now. Performance tweaks can
1896 	 * always be added.
1897 	 */
1898 
1899 	symbol = ef->strtab + sym->st_name;
1900 
1901 	/* Force a lookup failure if the symbol name is bogus. */
1902 	if (*symbol == 0) {
1903 		*res = 0;
1904 		return (EINVAL);
1905 	}
1906 
1907 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1908 	if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1909 		*res = 0;
1910 		return (EINVAL);
1911 	}
1912 
1913 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1914 		addr = addr - start + base;
1915 #ifdef VIMAGE
1916 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1917 		addr = addr - start + base;
1918 #endif
1919 	*res = addr;
1920 	return (0);
1921 }
1922 
1923 static void
link_elf_reloc_local(linker_file_t lf)1924 link_elf_reloc_local(linker_file_t lf)
1925 {
1926 	const Elf_Rel *rellim;
1927 	const Elf_Rel *rel;
1928 	const Elf_Rela *relalim;
1929 	const Elf_Rela *rela;
1930 	elf_file_t ef = (elf_file_t)lf;
1931 
1932 	/* Perform relocations without addend if there are any: */
1933 	if ((rel = ef->rel) != NULL) {
1934 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1935 		while (rel < rellim) {
1936 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1937 			    ELF_RELOC_REL, elf_lookup);
1938 			rel++;
1939 		}
1940 	}
1941 
1942 	/* Perform relocations with addend if there are any: */
1943 	if ((rela = ef->rela) != NULL) {
1944 		relalim = (const Elf_Rela *)
1945 		    ((const char *)ef->rela + ef->relasize);
1946 		while (rela < relalim) {
1947 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1948 			    ELF_RELOC_RELA, elf_lookup);
1949 			rela++;
1950 		}
1951 	}
1952 }
1953 
1954 static long
link_elf_symtab_get(linker_file_t lf,const Elf_Sym ** symtab)1955 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1956 {
1957 	elf_file_t ef = (elf_file_t)lf;
1958 
1959 	*symtab = ef->ddbsymtab;
1960 
1961 	if (*symtab == NULL)
1962 		return (0);
1963 
1964 	return (ef->ddbsymcnt);
1965 }
1966 
1967 static long
link_elf_strtab_get(linker_file_t lf,caddr_t * strtab)1968 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1969 {
1970 	elf_file_t ef = (elf_file_t)lf;
1971 
1972 	*strtab = ef->ddbstrtab;
1973 
1974 	if (*strtab == NULL)
1975 		return (0);
1976 
1977 	return (ef->ddbstrcnt);
1978 }
1979 
1980 #ifdef VIMAGE
1981 static void
link_elf_propagate_vnets(linker_file_t lf)1982 link_elf_propagate_vnets(linker_file_t lf)
1983 {
1984 	elf_file_t ef = (elf_file_t)lf;
1985 	int size;
1986 
1987 	if (ef->vnet_base != 0) {
1988 		size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
1989 		vnet_data_copy((void *)ef->vnet_base, size);
1990 	}
1991 }
1992 #endif
1993 
1994 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1995 /*
1996  * Use this lookup routine when performing relocations early during boot.
1997  * The generic lookup routine depends on kobj, which is not initialized
1998  * at that point.
1999  */
2000 static int
elf_lookup_ifunc(linker_file_t lf,Elf_Size symidx,int deps __unused,Elf_Addr * res)2001 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
2002     Elf_Addr *res)
2003 {
2004 	elf_file_t ef;
2005 	const Elf_Sym *symp;
2006 	caddr_t val;
2007 
2008 	ef = (elf_file_t)lf;
2009 	symp = ef->symtab + symidx;
2010 	if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
2011 		val = (caddr_t)ef->address + symp->st_value;
2012 		*res = ((Elf_Addr (*)(void))val)();
2013 		return (0);
2014 	}
2015 	return (ENOENT);
2016 }
2017 
2018 void
link_elf_ireloc(caddr_t kmdp)2019 link_elf_ireloc(caddr_t kmdp)
2020 {
2021 	struct elf_file eff;
2022 	elf_file_t ef;
2023 
2024 	TSENTER();
2025 	ef = &eff;
2026 
2027 	bzero_early(ef, sizeof(*ef));
2028 
2029 	ef->modptr = kmdp;
2030 	ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
2031 
2032 #ifdef RELOCATABLE_KERNEL
2033 	ef->address = (caddr_t) (__startkernel - KERNBASE);
2034 #else
2035 	ef->address = 0;
2036 #endif
2037 	parse_dynamic(ef);
2038 
2039 	link_elf_preload_parse_symbols(ef);
2040 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
2041 	TSEXIT();
2042 }
2043 
2044 #if defined(__aarch64__) || defined(__amd64__)
2045 void
link_elf_late_ireloc(void)2046 link_elf_late_ireloc(void)
2047 {
2048 	elf_file_t ef;
2049 
2050 	KASSERT(linker_kernel_file != NULL,
2051 	    ("link_elf_late_ireloc: No kernel linker file found"));
2052 	ef = (elf_file_t)linker_kernel_file;
2053 
2054 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);
2055 }
2056 #endif
2057 #endif
2058