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