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 <stdint.h>
34 #include <string.h>
35 #include <machine/elf.h>
36 #include <stand.h>
37 #include <sys/link_elf.h>
38
39 #include "bootstrap.h"
40
41 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l)
42
43 #if defined(__i386__) && __ELF_WORD_SIZE == 64
44 #undef ELF_TARG_CLASS
45 #undef ELF_TARG_MACH
46 #define ELF_TARG_CLASS ELFCLASS64
47 #define ELF_TARG_MACH EM_X86_64
48 #endif
49
50 typedef struct elf_file {
51 Elf_Ehdr hdr;
52 Elf_Shdr *e_shdr;
53
54 int symtabindex; /* Index of symbol table */
55 int shstrindex; /* Index of section name string table */
56
57 int fd;
58 vm_offset_t off;
59 #ifdef LOADER_VERIEXEC_VECTX
60 struct vectx *vctx;
61 #endif
62 } *elf_file_t;
63
64 #ifdef LOADER_VERIEXEC_VECTX
65 #define VECTX_HANDLE(ef) (ef)->vctx
66 #else
67 #define VECTX_HANDLE(ef) (ef)->fd
68 #endif
69
70 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
71 uint64_t loadaddr);
72 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
73 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
74 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
75 Elf_Addr p, void *val, size_t len);
76 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
77 elf_file_t ef);
78 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx);
79
80 const char *__elfN(obj_kerneltype) = "elf kernel";
81 const char *__elfN(obj_moduletype) = "elf obj module";
82
83 /*
84 * Attempt to load the file (file) as an ELF module. It will be stored at
85 * (dest), and a pointer to a module structure describing the loaded object
86 * will be saved in (result).
87 */
88 int
__elfN(obj_loadfile)89 __elfN(obj_loadfile)(char *filename, uint64_t dest,
90 struct preloaded_file **result)
91 {
92 struct preloaded_file *fp, *kfp;
93 struct elf_file ef;
94 Elf_Ehdr *hdr;
95 int err;
96 ssize_t bytes_read;
97
98 fp = NULL;
99 bzero(&ef, sizeof(struct elf_file));
100
101 /*
102 * Open the image, read and validate the ELF header
103 */
104 if (filename == NULL) /* can't handle nameless */
105 return(EFTYPE);
106 if ((ef.fd = open(filename, O_RDONLY)) == -1)
107 return(errno);
108 #ifdef LOADER_VERIEXEC_VECTX
109 {
110 int verror;
111
112 ef.vctx = vectx_open(ef.fd, filename, 0L, NULL, &verror, __func__);
113 if (verror) {
114 printf("Unverified %s: %s\n", filename, ve_error_get());
115 close(ef.fd);
116 free(ef.vctx);
117 return (EAUTH);
118 }
119 }
120 #endif
121
122 hdr = &ef.hdr;
123 bytes_read = VECTX_READ(VECTX_HANDLE(&ef), hdr, sizeof(*hdr));
124 if (bytes_read != sizeof(*hdr)) {
125 err = EFTYPE; /* could be EIO, but may be small file */
126 goto oerr;
127 }
128
129 /* Is it ELF? */
130 if (!IS_ELF(*hdr)) {
131 err = EFTYPE;
132 goto oerr;
133 }
134 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
135 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
136 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
137 hdr->e_version != EV_CURRENT ||
138 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */
139 hdr->e_type != ET_REL) {
140 err = EFTYPE;
141 goto oerr;
142 }
143
144 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
145 hdr->e_shentsize != sizeof(Elf_Shdr)) {
146 err = EFTYPE;
147 goto oerr;
148 }
149
150 #if defined(LOADER_VERIEXEC) && !defined(LOADER_VERIEXEC_VECTX)
151 if (verify_file(ef.fd, filename, bytes_read, VE_MUST, __func__) < 0) {
152 err = EAUTH;
153 goto oerr;
154 }
155 #endif
156
157 kfp = file_findfile(NULL, __elfN(obj_kerneltype));
158 if (kfp == NULL) {
159 printf("elf" __XSTRING(__ELF_WORD_SIZE)
160 "_obj_loadfile: can't load module before kernel\n");
161 err = EPERM;
162 goto oerr;
163 }
164
165 if (archsw.arch_loadaddr != NULL)
166 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
167 else
168 dest = roundup(dest, PAGE_SIZE);
169
170 /*
171 * Ok, we think we should handle this.
172 */
173 fp = file_alloc();
174 if (fp == NULL) {
175 printf("elf" __XSTRING(__ELF_WORD_SIZE)
176 "_obj_loadfile: cannot allocate module info\n");
177 err = EPERM;
178 goto out;
179 }
180 fp->f_name = strdup(filename);
181 fp->f_type = strdup(__elfN(obj_moduletype));
182
183 if (module_verbose > MODULE_VERBOSE_SILENT)
184 printf("%s ", filename);
185
186 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
187 if (fp->f_size == 0 || fp->f_addr == 0)
188 goto ioerr;
189
190 /* save exec header as metadata */
191 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
192
193 /* Load OK, return module pointer */
194 *result = (struct preloaded_file *)fp;
195 err = 0;
196 goto out;
197
198 ioerr:
199 err = EIO;
200 oerr:
201 file_discard(fp);
202 out:
203 #ifdef LOADER_VERIEXEC_VECTX
204 if (!err && ef.vctx) {
205 int verror;
206
207 verror = vectx_close(ef.vctx, VE_MUST, __func__);
208 if (verror) {
209 err = EAUTH;
210 file_discard(fp);
211 }
212 }
213 #endif
214 close(ef.fd);
215 if (ef.e_shdr != NULL)
216 free(ef.e_shdr);
217
218 return(err);
219 }
220
221 /*
222 * With the file (fd) open on the image, and (ehdr) containing
223 * the Elf header, load the image at (off)
224 */
225 static int
__elfN(obj_loadimage)226 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off)
227 {
228 Elf_Ehdr *hdr;
229 Elf_Shdr *shdr, *cshdr, *lshdr;
230 vm_offset_t firstaddr, lastaddr;
231 int i, nsym, res, ret, shdrbytes, symstrindex;
232
233 ret = 0;
234 firstaddr = lastaddr = (vm_offset_t)off;
235 hdr = &ef->hdr;
236 ef->off = (vm_offset_t)off;
237
238 /* Read in the section headers. */
239 shdrbytes = hdr->e_shnum * hdr->e_shentsize;
240 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes);
241 if (shdr == NULL) {
242 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
243 "_obj_loadimage: read section headers failed\n");
244 goto out;
245 }
246 ef->e_shdr = shdr;
247
248 /*
249 * Decide where to load everything, but don't read it yet.
250 * We store the load address as a non-zero sh_addr value.
251 * Start with the code/data and bss.
252 */
253 for (i = 0; i < hdr->e_shnum; i++)
254 shdr[i].sh_addr = 0;
255 for (i = 0; i < hdr->e_shnum; i++) {
256 if (shdr[i].sh_size == 0)
257 continue;
258 switch (shdr[i].sh_type) {
259 case SHT_PROGBITS:
260 case SHT_NOBITS:
261 #if defined(__i386__) || defined(__amd64__)
262 case SHT_X86_64_UNWIND:
263 #endif
264 case SHT_INIT_ARRAY:
265 case SHT_FINI_ARRAY:
266 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
267 break;
268 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
269 shdr[i].sh_addr = (Elf_Addr)lastaddr;
270 lastaddr += shdr[i].sh_size;
271 break;
272 }
273 }
274
275 /* Symbols. */
276 nsym = 0;
277 for (i = 0; i < hdr->e_shnum; i++) {
278 switch (shdr[i].sh_type) {
279 case SHT_SYMTAB:
280 nsym++;
281 ef->symtabindex = i;
282 break;
283 }
284 }
285 if (nsym != 1) {
286 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
287 "_obj_loadimage: file has no valid symbol table\n");
288 goto out;
289 }
290 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
291 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
292 lastaddr += shdr[ef->symtabindex].sh_size;
293
294 symstrindex = shdr[ef->symtabindex].sh_link;
295 if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
296 shdr[symstrindex].sh_type != SHT_STRTAB) {
297 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
298 "_obj_loadimage: file has invalid symbol strings\n");
299 goto out;
300 }
301 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
302 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
303 lastaddr += shdr[symstrindex].sh_size;
304
305 /* Section names. */
306 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
307 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
308 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
309 "_obj_loadimage: file has no section names\n");
310 goto out;
311 }
312 ef->shstrindex = hdr->e_shstrndx;
313 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
314 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
315 lastaddr += shdr[ef->shstrindex].sh_size;
316
317 /* Relocation tables. */
318 for (i = 0; i < hdr->e_shnum; i++) {
319 switch (shdr[i].sh_type) {
320 case SHT_REL:
321 case SHT_RELA:
322 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
323 break;
324 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
325 shdr[i].sh_addr = (Elf_Addr)lastaddr;
326 lastaddr += shdr[i].sh_size;
327 break;
328 }
329 }
330
331 /* Clear the whole area, including bss regions. */
332 kern_bzero(firstaddr, lastaddr - firstaddr);
333
334 /* Figure section with the lowest file offset we haven't loaded yet. */
335 for (cshdr = NULL; /* none */; /* none */)
336 {
337 /*
338 * Find next section to load. The complexity of this loop is
339 * O(n^2), but with the number of sections being typically
340 * small, we do not care.
341 */
342 lshdr = cshdr;
343
344 for (i = 0; i < hdr->e_shnum; i++) {
345 if (shdr[i].sh_addr == 0 ||
346 shdr[i].sh_type == SHT_NOBITS)
347 continue;
348 /* Skip sections that were loaded already. */
349 if (lshdr != NULL &&
350 lshdr->sh_offset >= shdr[i].sh_offset)
351 continue;
352 /* Find section with smallest offset. */
353 if (cshdr == lshdr ||
354 cshdr->sh_offset > shdr[i].sh_offset)
355 cshdr = &shdr[i];
356 }
357
358 if (cshdr == lshdr)
359 break;
360
361 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr,
362 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
363 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
364 "_obj_loadimage: read failed\n");
365 goto out;
366 }
367 }
368
369 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
370
371 res = __elfN(obj_parse_modmetadata)(fp, ef);
372 if (res != 0)
373 goto out;
374
375 ret = lastaddr - firstaddr;
376 fp->f_addr = firstaddr;
377
378 if (module_verbose > MODULE_VERBOSE_SILENT)
379 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
380
381 out:
382 if (module_verbose > MODULE_VERBOSE_SILENT)
383 printf("\n");
384 return ret;
385 }
386
387 #if defined(__i386__) && __ELF_WORD_SIZE == 64
388 struct mod_metadata64 {
389 int md_version; /* structure version MDTV_* */
390 int md_type; /* type of entry MDT_* */
391 uint64_t md_data; /* specific data */
392 uint64_t md_cval; /* common string label */
393 };
394 #endif
395
396 int
__elfN(obj_parse_modmetadata)397 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
398 {
399 struct mod_metadata md;
400 #if defined(__i386__) && __ELF_WORD_SIZE == 64
401 struct mod_metadata64 md64;
402 #endif
403 struct mod_depend *mdepend;
404 struct mod_version mver;
405 char *s;
406 int error, modcnt, minfolen;
407 Elf_Addr v, p, p_stop;
408
409 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
410 &modcnt) != 0)
411 return 0;
412
413 modcnt = 0;
414 while (p < p_stop) {
415 COPYOUT(p, &v, sizeof(v));
416 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
417 if (error != 0)
418 return (error);
419 #if defined(__i386__) && __ELF_WORD_SIZE == 64
420 COPYOUT(v, &md64, sizeof(md64));
421 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
422 if (error != 0)
423 return (error);
424 md.md_version = md64.md_version;
425 md.md_type = md64.md_type;
426 md.md_cval = (const char *)(uintptr_t)md64.md_cval;
427 md.md_data = (void *)(uintptr_t)md64.md_data;
428 #else
429 COPYOUT(v, &md, sizeof(md));
430 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
431 if (error != 0)
432 return (error);
433 #endif
434 p += sizeof(Elf_Addr);
435 switch(md.md_type) {
436 case MDT_DEPEND:
437 s = strdupout((vm_offset_t)md.md_cval);
438 minfolen = sizeof(*mdepend) + strlen(s) + 1;
439 mdepend = malloc(minfolen);
440 if (mdepend == NULL)
441 return ENOMEM;
442 COPYOUT((vm_offset_t)md.md_data, mdepend,
443 sizeof(*mdepend));
444 strcpy((char*)(mdepend + 1), s);
445 free(s);
446 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
447 mdepend);
448 free(mdepend);
449 break;
450 case MDT_VERSION:
451 s = strdupout((vm_offset_t)md.md_cval);
452 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
453 file_addmodule(fp, s, mver.mv_version, NULL);
454 free(s);
455 modcnt++;
456 break;
457 case MDT_MODULE:
458 case MDT_PNP_INFO:
459 break;
460 default:
461 printf("unknown type %d\n", md.md_type);
462 break;
463 }
464 }
465 return 0;
466 }
467
468 static int
__elfN(obj_lookup_set)469 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef,
470 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
471 {
472 Elf_Ehdr *hdr;
473 Elf_Shdr *shdr;
474 char *p;
475 vm_offset_t shstrtab;
476 int i;
477
478 hdr = &ef->hdr;
479 shdr = ef->e_shdr;
480 shstrtab = shdr[ef->shstrindex].sh_addr;
481
482 for (i = 0; i < hdr->e_shnum; i++) {
483 if (shdr[i].sh_type != SHT_PROGBITS)
484 continue;
485 if (shdr[i].sh_name == 0)
486 continue;
487 p = strdupout(shstrtab + shdr[i].sh_name);
488 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
489 *startp = shdr[i].sh_addr;
490 *stopp = shdr[i].sh_addr + shdr[i].sh_size;
491 *countp = (*stopp - *startp) / sizeof(Elf_Addr);
492 free(p);
493 return (0);
494 }
495 free(p);
496 }
497
498 return (ESRCH);
499 }
500
501 /*
502 * Apply any intra-module relocations to the value. p is the load address
503 * of the value and val/len is the value to be modified. This does NOT modify
504 * the image in-place, because this is done by kern_linker later on.
505 */
506 static int
__elfN(obj_reloc_ptr)507 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
508 void *val, size_t len)
509 {
510 Elf_Ehdr *hdr;
511 Elf_Shdr *shdr;
512 Elf_Addr off = p;
513 Elf_Addr base;
514 Elf_Rela a, *abase;
515 Elf_Rel r, *rbase;
516 int error, i, j, nrel, nrela;
517
518 hdr = &ef->hdr;
519 shdr = ef->e_shdr;
520
521 for (i = 0; i < hdr->e_shnum; i++) {
522 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
523 continue;
524 base = shdr[shdr[i].sh_info].sh_addr;
525 if (base == 0 || shdr[i].sh_addr == 0)
526 continue;
527 if (off < base || off + len > base +
528 shdr[shdr[i].sh_info].sh_size)
529 continue;
530
531 switch (shdr[i].sh_type) {
532 case SHT_RELA:
533 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
534
535 nrela = shdr[i].sh_size / sizeof(Elf_Rela);
536 for (j = 0; j < nrela; j++) {
537 COPYOUT(abase + j, &a, sizeof(a));
538
539 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
540 &a, ELF_RELOC_RELA, base, off, val, len);
541 if (error != 0)
542 return (error);
543 }
544 break;
545 case SHT_REL:
546 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
547
548 nrel = shdr[i].sh_size / sizeof(Elf_Rel);
549 for (j = 0; j < nrel; j++) {
550 COPYOUT(rbase + j, &r, sizeof(r));
551
552 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
553 &r, ELF_RELOC_REL, base, off, val, len);
554 if (error != 0)
555 return (error);
556 }
557 break;
558 }
559 }
560 return (0);
561 }
562
563 /* Look up the address of a specified symbol. */
564 static Elf_Addr
__elfN(obj_symaddr)565 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
566 {
567 Elf_Sym sym;
568 Elf_Addr base;
569
570 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym))
571 return (0);
572 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
573 &sym, sizeof(sym));
574 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
575 return (0);
576 base = ef->e_shdr[sym.st_shndx].sh_addr;
577 if (base == 0)
578 return (0);
579 return (base + sym.st_value);
580 }
581