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