1 /*-
2 * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org>
3 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
4 * Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
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/param.h>
30 #include <sys/exec.h>
31 #include <sys/linker.h>
32 #include <sys/module.h>
33 #include <machine/elf.h>
34 #include <stand.h>
35
36 #include "bootstrap.h"
37 #include "modinfo.h"
38
39 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l)
40
41 #if defined(__i386__) && __ELF_WORD_SIZE == 64
42 #undef ELF_TARG_CLASS
43 #undef ELF_TARG_MACH
44 #define ELF_TARG_CLASS ELFCLASS64
45 #define ELF_TARG_MACH EM_X86_64
46 #endif
47
48 typedef struct elf_file {
49 Elf_Ehdr hdr;
50 Elf_Shdr *e_shdr;
51
52 int symtabindex; /* Index of symbol table */
53 int shstrindex; /* Index of section name string table */
54
55 int fd;
56 vm_offset_t off;
57 #ifdef LOADER_VERIEXEC_VECTX
58 struct vectx *vctx;
59 #endif
60 } *elf_file_t;
61
62 #ifdef LOADER_VERIEXEC_VECTX
63 #define VECTX_HANDLE(ef) (ef)->vctx
64 #else
65 #define VECTX_HANDLE(ef) (ef)->fd
66 #endif
67
68 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
69 uint64_t loadaddr);
70 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
71 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
72 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
73 Elf_Addr p, void *val, size_t len);
74 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
75 elf_file_t ef);
76 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx);
77
78 /*
79 * Attempt to load the file (file) as an ELF module. It will be stored at
80 * (dest), and a pointer to a module structure describing the loaded object
81 * will be saved in (result).
82 */
83 int
__elfN(obj_loadfile)84 __elfN(obj_loadfile)(char *filename, uint64_t dest,
85 struct preloaded_file **result)
86 {
87 struct preloaded_file *fp, *kfp;
88 struct elf_file ef;
89 Elf_Ehdr *hdr;
90 int err;
91 ssize_t bytes_read;
92
93 fp = NULL;
94 bzero(&ef, sizeof(struct elf_file));
95
96 /*
97 * Open the image, read and validate the ELF header
98 */
99 if (filename == NULL) /* can't handle nameless */
100 return(EFTYPE);
101 if ((ef.fd = open(filename, O_RDONLY)) == -1)
102 return(errno);
103 #ifdef LOADER_VERIEXEC_VECTX
104 {
105 int verror;
106
107 ef.vctx = vectx_open(ef.fd, filename, VE_MUST,
108 0L, NULL, &verror, __func__);
109 if (verror) {
110 printf("Unverified %s: %s\n", filename, ve_error_get());
111 close(ef.fd);
112 free(ef.vctx);
113 return (EAUTH);
114 }
115 }
116 #endif
117
118 hdr = &ef.hdr;
119 bytes_read = VECTX_READ(VECTX_HANDLE(&ef), hdr, sizeof(*hdr));
120 if (bytes_read != sizeof(*hdr)) {
121 err = EFTYPE; /* could be EIO, but may be small file */
122 goto oerr;
123 }
124
125 /* Is it ELF? */
126 if (!IS_ELF(*hdr)) {
127 err = EFTYPE;
128 goto oerr;
129 }
130 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
131 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
132 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
133 hdr->e_version != EV_CURRENT ||
134 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */
135 hdr->e_type != ET_REL) {
136 err = EFTYPE;
137 goto oerr;
138 }
139
140 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
141 hdr->e_shentsize != sizeof(Elf_Shdr)) {
142 err = EFTYPE;
143 goto oerr;
144 }
145
146 #if defined(LOADER_VERIEXEC) && !defined(LOADER_VERIEXEC_VECTX)
147 if (verify_file(ef.fd, filename, bytes_read, VE_MUST, __func__) < 0) {
148 err = EAUTH;
149 goto oerr;
150 }
151 #endif
152
153 kfp = file_findfile(NULL, md_kerntype);
154 if (kfp == NULL) {
155 printf("elf" __XSTRING(__ELF_WORD_SIZE)
156 "_obj_loadfile: can't load module before kernel\n");
157 err = EPERM;
158 goto oerr;
159 }
160
161 dest = md_align(dest);
162
163 /*
164 * Ok, we think we should handle this.
165 */
166 fp = file_alloc();
167 if (fp == NULL) {
168 printf("elf" __XSTRING(__ELF_WORD_SIZE)
169 "_obj_loadfile: cannot allocate module info\n");
170 err = EPERM;
171 goto out;
172 }
173 fp->f_name = strdup(filename);
174 fp->f_type = strdup(md_modtype_obj);
175
176 if (module_verbose > MODULE_VERBOSE_SILENT)
177 printf("%s ", filename);
178
179 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
180 if (fp->f_size == 0 || fp->f_addr == 0)
181 goto ioerr;
182
183 /* save exec header as metadata */
184 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
185
186 /* Load OK, return module pointer */
187 *result = (struct preloaded_file *)fp;
188 err = 0;
189 goto out;
190
191 ioerr:
192 err = EIO;
193 oerr:
194 file_discard(fp);
195 out:
196 #ifdef LOADER_VERIEXEC_VECTX
197 if (!err && ef.vctx) {
198 int verror;
199
200 verror = vectx_close(ef.vctx, __func__);
201 if (verror) {
202 err = EAUTH;
203 file_discard(fp);
204 }
205 }
206 #endif
207 close(ef.fd);
208 if (ef.e_shdr != NULL)
209 free(ef.e_shdr);
210
211 return(err);
212 }
213
214 /*
215 * With the file (fd) open on the image, and (ehdr) containing
216 * the Elf header, load the image at (off)
217 */
218 static int
__elfN(obj_loadimage)219 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off)
220 {
221 Elf_Ehdr *hdr;
222 Elf_Shdr *shdr, *cshdr, *lshdr;
223 vm_offset_t firstaddr, lastaddr;
224 int i, nsym, res, ret, shdrbytes, symstrindex;
225
226 ret = 0;
227 firstaddr = lastaddr = (vm_offset_t)off;
228 hdr = &ef->hdr;
229 ef->off = (vm_offset_t)off;
230
231 /* Read in the section headers. */
232 shdrbytes = hdr->e_shnum * hdr->e_shentsize;
233 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes);
234 if (shdr == NULL) {
235 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
236 "_obj_loadimage: read section headers failed\n");
237 goto out;
238 }
239 ef->e_shdr = shdr;
240
241 /*
242 * Decide where to load everything, but don't read it yet.
243 * We store the load address as a non-zero sh_addr value.
244 * Start with the code/data and bss.
245 */
246 for (i = 0; i < hdr->e_shnum; i++)
247 shdr[i].sh_addr = 0;
248 for (i = 0; i < hdr->e_shnum; i++) {
249 if (shdr[i].sh_size == 0)
250 continue;
251 switch (shdr[i].sh_type) {
252 case SHT_PROGBITS:
253 case SHT_NOBITS:
254 #if defined(__i386__) || defined(__amd64__)
255 case SHT_X86_64_UNWIND:
256 #endif
257 case SHT_INIT_ARRAY:
258 case SHT_FINI_ARRAY:
259 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
260 break;
261 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
262 shdr[i].sh_addr = (Elf_Addr)lastaddr;
263 lastaddr += shdr[i].sh_size;
264 break;
265 }
266 }
267
268 /* Symbols. */
269 nsym = 0;
270 for (i = 0; i < hdr->e_shnum; i++) {
271 switch (shdr[i].sh_type) {
272 case SHT_SYMTAB:
273 nsym++;
274 ef->symtabindex = i;
275 break;
276 }
277 }
278 if (nsym != 1) {
279 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
280 "_obj_loadimage: file has no valid symbol table\n");
281 goto out;
282 }
283 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
284 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
285 lastaddr += shdr[ef->symtabindex].sh_size;
286
287 symstrindex = shdr[ef->symtabindex].sh_link;
288 if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
289 shdr[symstrindex].sh_type != SHT_STRTAB) {
290 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
291 "_obj_loadimage: file has invalid symbol strings\n");
292 goto out;
293 }
294 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
295 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
296 lastaddr += shdr[symstrindex].sh_size;
297
298 /* Section names. */
299 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
300 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
301 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
302 "_obj_loadimage: file has no section names\n");
303 goto out;
304 }
305 ef->shstrindex = hdr->e_shstrndx;
306 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
307 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
308 lastaddr += shdr[ef->shstrindex].sh_size;
309
310 /* Relocation tables. */
311 for (i = 0; i < hdr->e_shnum; i++) {
312 switch (shdr[i].sh_type) {
313 case SHT_REL:
314 case SHT_RELA:
315 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
316 break;
317 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
318 shdr[i].sh_addr = (Elf_Addr)lastaddr;
319 lastaddr += shdr[i].sh_size;
320 break;
321 }
322 }
323
324 /* Clear the whole area, including bss regions. */
325 kern_bzero(firstaddr, lastaddr - firstaddr);
326
327 /* Figure section with the lowest file offset we haven't loaded yet. */
328 for (cshdr = NULL; /* none */; /* none */)
329 {
330 /*
331 * Find next section to load. The complexity of this loop is
332 * O(n^2), but with the number of sections being typically
333 * small, we do not care.
334 */
335 lshdr = cshdr;
336
337 for (i = 0; i < hdr->e_shnum; i++) {
338 if (shdr[i].sh_addr == 0 ||
339 shdr[i].sh_type == SHT_NOBITS)
340 continue;
341 /* Skip sections that were loaded already. */
342 if (lshdr != NULL &&
343 lshdr->sh_offset >= shdr[i].sh_offset)
344 continue;
345 /* Find section with smallest offset. */
346 if (cshdr == lshdr ||
347 cshdr->sh_offset > shdr[i].sh_offset)
348 cshdr = &shdr[i];
349 }
350
351 if (cshdr == lshdr)
352 break;
353
354 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr,
355 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
356 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
357 "_obj_loadimage: read failed\n");
358 goto out;
359 }
360 }
361
362 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
363
364 res = __elfN(obj_parse_modmetadata)(fp, ef);
365 if (res != 0)
366 goto out;
367
368 ret = lastaddr - firstaddr;
369 fp->f_addr = firstaddr;
370
371 if (module_verbose > MODULE_VERBOSE_SILENT)
372 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
373
374 out:
375 if (module_verbose > MODULE_VERBOSE_SILENT)
376 printf("\n");
377 return ret;
378 }
379
380 #if defined(__i386__) && __ELF_WORD_SIZE == 64
381 struct mod_metadata64 {
382 int md_version; /* structure version MDTV_* */
383 int md_type; /* type of entry MDT_* */
384 uint64_t md_data; /* specific data */
385 uint64_t md_cval; /* common string label */
386 };
387 #endif
388
389 int
__elfN(obj_parse_modmetadata)390 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
391 {
392 struct mod_metadata md;
393 #if defined(__i386__) && __ELF_WORD_SIZE == 64
394 struct mod_metadata64 md64;
395 #endif
396 struct mod_depend *mdepend;
397 struct mod_version mver;
398 char *s;
399 int error, modcnt, minfolen;
400 Elf_Addr v, p, p_stop;
401
402 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
403 &modcnt) != 0)
404 return 0;
405
406 modcnt = 0;
407 while (p < p_stop) {
408 COPYOUT(p, &v, sizeof(v));
409 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
410 if (error != 0)
411 return (error);
412 #if defined(__i386__) && __ELF_WORD_SIZE == 64
413 COPYOUT(v, &md64, sizeof(md64));
414 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
415 if (error != 0)
416 return (error);
417 md.md_version = md64.md_version;
418 md.md_type = md64.md_type;
419 md.md_cval = (const char *)(uintptr_t)md64.md_cval;
420 md.md_data = (void *)(uintptr_t)md64.md_data;
421 #else
422 COPYOUT(v, &md, sizeof(md));
423 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
424 if (error != 0)
425 return (error);
426 #endif
427 p += sizeof(Elf_Addr);
428 switch(md.md_type) {
429 case MDT_DEPEND:
430 s = strdupout((vm_offset_t)md.md_cval);
431 minfolen = sizeof(*mdepend) + strlen(s) + 1;
432 mdepend = malloc(minfolen);
433 if (mdepend == NULL)
434 return ENOMEM;
435 COPYOUT((vm_offset_t)md.md_data, mdepend,
436 sizeof(*mdepend));
437 strcpy((char*)(mdepend + 1), s);
438 free(s);
439 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
440 mdepend);
441 free(mdepend);
442 break;
443 case MDT_VERSION:
444 s = strdupout((vm_offset_t)md.md_cval);
445 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
446 file_addmodule(fp, s, mver.mv_version, NULL);
447 free(s);
448 modcnt++;
449 break;
450 case MDT_MODULE:
451 case MDT_PNP_INFO:
452 break;
453 default:
454 printf("unknown type %d\n", md.md_type);
455 break;
456 }
457 }
458 return 0;
459 }
460
461 static int
__elfN(obj_lookup_set)462 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef,
463 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
464 {
465 Elf_Ehdr *hdr;
466 Elf_Shdr *shdr;
467 char *p;
468 vm_offset_t shstrtab;
469 int i;
470
471 hdr = &ef->hdr;
472 shdr = ef->e_shdr;
473 shstrtab = shdr[ef->shstrindex].sh_addr;
474
475 for (i = 0; i < hdr->e_shnum; i++) {
476 if (shdr[i].sh_type != SHT_PROGBITS)
477 continue;
478 if (shdr[i].sh_name == 0)
479 continue;
480 p = strdupout(shstrtab + shdr[i].sh_name);
481 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
482 *startp = shdr[i].sh_addr;
483 *stopp = shdr[i].sh_addr + shdr[i].sh_size;
484 *countp = (*stopp - *startp) / sizeof(Elf_Addr);
485 free(p);
486 return (0);
487 }
488 free(p);
489 }
490
491 return (ESRCH);
492 }
493
494 /*
495 * Apply any intra-module relocations to the value. p is the load address
496 * of the value and val/len is the value to be modified. This does NOT modify
497 * the image in-place, because this is done by kern_linker later on.
498 */
499 static int
__elfN(obj_reloc_ptr)500 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
501 void *val, size_t len)
502 {
503 Elf_Ehdr *hdr;
504 Elf_Shdr *shdr;
505 Elf_Addr off = p;
506 Elf_Addr base;
507 Elf_Rela a, *abase;
508 Elf_Rel r, *rbase;
509 int error, i, j, nrel, nrela;
510
511 hdr = &ef->hdr;
512 shdr = ef->e_shdr;
513
514 for (i = 0; i < hdr->e_shnum; i++) {
515 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
516 continue;
517 base = shdr[shdr[i].sh_info].sh_addr;
518 if (base == 0 || shdr[i].sh_addr == 0)
519 continue;
520 if (off < base || off + len > base +
521 shdr[shdr[i].sh_info].sh_size)
522 continue;
523
524 switch (shdr[i].sh_type) {
525 case SHT_RELA:
526 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
527
528 nrela = shdr[i].sh_size / sizeof(Elf_Rela);
529 for (j = 0; j < nrela; j++) {
530 COPYOUT(abase + j, &a, sizeof(a));
531
532 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
533 &a, ELF_RELOC_RELA, base, off, val, len);
534 if (error != 0)
535 return (error);
536 }
537 break;
538 case SHT_REL:
539 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
540
541 nrel = shdr[i].sh_size / sizeof(Elf_Rel);
542 for (j = 0; j < nrel; j++) {
543 COPYOUT(rbase + j, &r, sizeof(r));
544
545 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
546 &r, ELF_RELOC_REL, base, off, val, len);
547 if (error != 0)
548 return (error);
549 }
550 break;
551 }
552 }
553 return (0);
554 }
555
556 /* Look up the address of a specified symbol. */
557 static Elf_Addr
__elfN(obj_symaddr)558 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
559 {
560 Elf_Sym sym;
561 Elf_Addr base;
562
563 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym))
564 return (0);
565 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
566 &sym, sizeof(sym));
567 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
568 return (0);
569 base = ef->e_shdr[sym.st_shndx].sh_addr;
570 if (base == 0)
571 return (0);
572 return (base + sym.st_value);
573 }
574