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 if (archsw.arch_loadaddr != NULL)
161 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
162 else
163 dest = roundup(dest, PAGE_SIZE);
164
165 /*
166 * Ok, we think we should handle this.
167 */
168 fp = file_alloc();
169 if (fp == NULL) {
170 printf("elf" __XSTRING(__ELF_WORD_SIZE)
171 "_obj_loadfile: cannot allocate module info\n");
172 err = EPERM;
173 goto out;
174 }
175 fp->f_name = strdup(filename);
176 fp->f_type = strdup(md_modtype_obj);
177
178 if (module_verbose > MODULE_VERBOSE_SILENT)
179 printf("%s ", filename);
180
181 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
182 if (fp->f_size == 0 || fp->f_addr == 0)
183 goto ioerr;
184
185 /* save exec header as metadata */
186 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
187
188 /* Load OK, return module pointer */
189 *result = (struct preloaded_file *)fp;
190 err = 0;
191 goto out;
192
193 ioerr:
194 err = EIO;
195 oerr:
196 file_discard(fp);
197 out:
198 #ifdef LOADER_VERIEXEC_VECTX
199 if (!err && ef.vctx) {
200 int verror;
201
202 verror = vectx_close(ef.vctx, VE_MUST, __func__);
203 if (verror) {
204 err = EAUTH;
205 file_discard(fp);
206 }
207 }
208 #endif
209 close(ef.fd);
210 if (ef.e_shdr != NULL)
211 free(ef.e_shdr);
212
213 return(err);
214 }
215
216 /*
217 * With the file (fd) open on the image, and (ehdr) containing
218 * the Elf header, load the image at (off)
219 */
220 static int
__elfN(obj_loadimage)221 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off)
222 {
223 Elf_Ehdr *hdr;
224 Elf_Shdr *shdr, *cshdr, *lshdr;
225 vm_offset_t firstaddr, lastaddr;
226 int i, nsym, res, ret, shdrbytes, symstrindex;
227
228 ret = 0;
229 firstaddr = lastaddr = (vm_offset_t)off;
230 hdr = &ef->hdr;
231 ef->off = (vm_offset_t)off;
232
233 /* Read in the section headers. */
234 shdrbytes = hdr->e_shnum * hdr->e_shentsize;
235 shdr = alloc_pread(VECTX_HANDLE(ef), (off_t)hdr->e_shoff, shdrbytes);
236 if (shdr == NULL) {
237 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
238 "_obj_loadimage: read section headers failed\n");
239 goto out;
240 }
241 ef->e_shdr = shdr;
242
243 /*
244 * Decide where to load everything, but don't read it yet.
245 * We store the load address as a non-zero sh_addr value.
246 * Start with the code/data and bss.
247 */
248 for (i = 0; i < hdr->e_shnum; i++)
249 shdr[i].sh_addr = 0;
250 for (i = 0; i < hdr->e_shnum; i++) {
251 if (shdr[i].sh_size == 0)
252 continue;
253 switch (shdr[i].sh_type) {
254 case SHT_PROGBITS:
255 case SHT_NOBITS:
256 #if defined(__i386__) || defined(__amd64__)
257 case SHT_X86_64_UNWIND:
258 #endif
259 case SHT_INIT_ARRAY:
260 case SHT_FINI_ARRAY:
261 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
262 break;
263 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
264 shdr[i].sh_addr = (Elf_Addr)lastaddr;
265 lastaddr += shdr[i].sh_size;
266 break;
267 }
268 }
269
270 /* Symbols. */
271 nsym = 0;
272 for (i = 0; i < hdr->e_shnum; i++) {
273 switch (shdr[i].sh_type) {
274 case SHT_SYMTAB:
275 nsym++;
276 ef->symtabindex = i;
277 break;
278 }
279 }
280 if (nsym != 1) {
281 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
282 "_obj_loadimage: file has no valid symbol table\n");
283 goto out;
284 }
285 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
286 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
287 lastaddr += shdr[ef->symtabindex].sh_size;
288
289 symstrindex = shdr[ef->symtabindex].sh_link;
290 if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
291 shdr[symstrindex].sh_type != SHT_STRTAB) {
292 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
293 "_obj_loadimage: file has invalid symbol strings\n");
294 goto out;
295 }
296 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
297 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
298 lastaddr += shdr[symstrindex].sh_size;
299
300 /* Section names. */
301 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
302 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
303 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
304 "_obj_loadimage: file has no section names\n");
305 goto out;
306 }
307 ef->shstrindex = hdr->e_shstrndx;
308 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
309 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
310 lastaddr += shdr[ef->shstrindex].sh_size;
311
312 /* Relocation tables. */
313 for (i = 0; i < hdr->e_shnum; i++) {
314 switch (shdr[i].sh_type) {
315 case SHT_REL:
316 case SHT_RELA:
317 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
318 break;
319 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
320 shdr[i].sh_addr = (Elf_Addr)lastaddr;
321 lastaddr += shdr[i].sh_size;
322 break;
323 }
324 }
325
326 /* Clear the whole area, including bss regions. */
327 kern_bzero(firstaddr, lastaddr - firstaddr);
328
329 /* Figure section with the lowest file offset we haven't loaded yet. */
330 for (cshdr = NULL; /* none */; /* none */)
331 {
332 /*
333 * Find next section to load. The complexity of this loop is
334 * O(n^2), but with the number of sections being typically
335 * small, we do not care.
336 */
337 lshdr = cshdr;
338
339 for (i = 0; i < hdr->e_shnum; i++) {
340 if (shdr[i].sh_addr == 0 ||
341 shdr[i].sh_type == SHT_NOBITS)
342 continue;
343 /* Skip sections that were loaded already. */
344 if (lshdr != NULL &&
345 lshdr->sh_offset >= shdr[i].sh_offset)
346 continue;
347 /* Find section with smallest offset. */
348 if (cshdr == lshdr ||
349 cshdr->sh_offset > shdr[i].sh_offset)
350 cshdr = &shdr[i];
351 }
352
353 if (cshdr == lshdr)
354 break;
355
356 if (kern_pread(VECTX_HANDLE(ef), (vm_offset_t)cshdr->sh_addr,
357 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
358 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
359 "_obj_loadimage: read failed\n");
360 goto out;
361 }
362 }
363
364 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
365
366 res = __elfN(obj_parse_modmetadata)(fp, ef);
367 if (res != 0)
368 goto out;
369
370 ret = lastaddr - firstaddr;
371 fp->f_addr = firstaddr;
372
373 if (module_verbose > MODULE_VERBOSE_SILENT)
374 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
375
376 out:
377 if (module_verbose > MODULE_VERBOSE_SILENT)
378 printf("\n");
379 return ret;
380 }
381
382 #if defined(__i386__) && __ELF_WORD_SIZE == 64
383 struct mod_metadata64 {
384 int md_version; /* structure version MDTV_* */
385 int md_type; /* type of entry MDT_* */
386 uint64_t md_data; /* specific data */
387 uint64_t md_cval; /* common string label */
388 };
389 #endif
390
391 int
__elfN(obj_parse_modmetadata)392 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
393 {
394 struct mod_metadata md;
395 #if defined(__i386__) && __ELF_WORD_SIZE == 64
396 struct mod_metadata64 md64;
397 #endif
398 struct mod_depend *mdepend;
399 struct mod_version mver;
400 char *s;
401 int error, modcnt, minfolen;
402 Elf_Addr v, p, p_stop;
403
404 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
405 &modcnt) != 0)
406 return 0;
407
408 modcnt = 0;
409 while (p < p_stop) {
410 COPYOUT(p, &v, sizeof(v));
411 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
412 if (error != 0)
413 return (error);
414 #if defined(__i386__) && __ELF_WORD_SIZE == 64
415 COPYOUT(v, &md64, sizeof(md64));
416 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
417 if (error != 0)
418 return (error);
419 md.md_version = md64.md_version;
420 md.md_type = md64.md_type;
421 md.md_cval = (const char *)(uintptr_t)md64.md_cval;
422 md.md_data = (void *)(uintptr_t)md64.md_data;
423 #else
424 COPYOUT(v, &md, sizeof(md));
425 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
426 if (error != 0)
427 return (error);
428 #endif
429 p += sizeof(Elf_Addr);
430 switch(md.md_type) {
431 case MDT_DEPEND:
432 s = strdupout((vm_offset_t)md.md_cval);
433 minfolen = sizeof(*mdepend) + strlen(s) + 1;
434 mdepend = malloc(minfolen);
435 if (mdepend == NULL)
436 return ENOMEM;
437 COPYOUT((vm_offset_t)md.md_data, mdepend,
438 sizeof(*mdepend));
439 strcpy((char*)(mdepend + 1), s);
440 free(s);
441 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
442 mdepend);
443 free(mdepend);
444 break;
445 case MDT_VERSION:
446 s = strdupout((vm_offset_t)md.md_cval);
447 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
448 file_addmodule(fp, s, mver.mv_version, NULL);
449 free(s);
450 modcnt++;
451 break;
452 case MDT_MODULE:
453 case MDT_PNP_INFO:
454 break;
455 default:
456 printf("unknown type %d\n", md.md_type);
457 break;
458 }
459 }
460 return 0;
461 }
462
463 static int
__elfN(obj_lookup_set)464 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef,
465 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
466 {
467 Elf_Ehdr *hdr;
468 Elf_Shdr *shdr;
469 char *p;
470 vm_offset_t shstrtab;
471 int i;
472
473 hdr = &ef->hdr;
474 shdr = ef->e_shdr;
475 shstrtab = shdr[ef->shstrindex].sh_addr;
476
477 for (i = 0; i < hdr->e_shnum; i++) {
478 if (shdr[i].sh_type != SHT_PROGBITS)
479 continue;
480 if (shdr[i].sh_name == 0)
481 continue;
482 p = strdupout(shstrtab + shdr[i].sh_name);
483 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
484 *startp = shdr[i].sh_addr;
485 *stopp = shdr[i].sh_addr + shdr[i].sh_size;
486 *countp = (*stopp - *startp) / sizeof(Elf_Addr);
487 free(p);
488 return (0);
489 }
490 free(p);
491 }
492
493 return (ESRCH);
494 }
495
496 /*
497 * Apply any intra-module relocations to the value. p is the load address
498 * of the value and val/len is the value to be modified. This does NOT modify
499 * the image in-place, because this is done by kern_linker later on.
500 */
501 static int
__elfN(obj_reloc_ptr)502 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
503 void *val, size_t len)
504 {
505 Elf_Ehdr *hdr;
506 Elf_Shdr *shdr;
507 Elf_Addr off = p;
508 Elf_Addr base;
509 Elf_Rela a, *abase;
510 Elf_Rel r, *rbase;
511 int error, i, j, nrel, nrela;
512
513 hdr = &ef->hdr;
514 shdr = ef->e_shdr;
515
516 for (i = 0; i < hdr->e_shnum; i++) {
517 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
518 continue;
519 base = shdr[shdr[i].sh_info].sh_addr;
520 if (base == 0 || shdr[i].sh_addr == 0)
521 continue;
522 if (off < base || off + len > base +
523 shdr[shdr[i].sh_info].sh_size)
524 continue;
525
526 switch (shdr[i].sh_type) {
527 case SHT_RELA:
528 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
529
530 nrela = shdr[i].sh_size / sizeof(Elf_Rela);
531 for (j = 0; j < nrela; j++) {
532 COPYOUT(abase + j, &a, sizeof(a));
533
534 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
535 &a, ELF_RELOC_RELA, base, off, val, len);
536 if (error != 0)
537 return (error);
538 }
539 break;
540 case SHT_REL:
541 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
542
543 nrel = shdr[i].sh_size / sizeof(Elf_Rel);
544 for (j = 0; j < nrel; j++) {
545 COPYOUT(rbase + j, &r, sizeof(r));
546
547 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
548 &r, ELF_RELOC_REL, base, off, val, len);
549 if (error != 0)
550 return (error);
551 }
552 break;
553 }
554 }
555 return (0);
556 }
557
558 /* Look up the address of a specified symbol. */
559 static Elf_Addr
__elfN(obj_symaddr)560 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
561 {
562 Elf_Sym sym;
563 Elf_Addr base;
564
565 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym))
566 return (0);
567 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
568 &sym, sizeof(sym));
569 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
570 return (0);
571 base = ef->e_shdr[sym.st_shndx].sh_addr;
572 if (base == 0)
573 return (0);
574 return (base + sym.st_value);
575 }
576