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1 | /* |
2 | * kexec: kexec_file_load system call | |
3 | * | |
4 | * Copyright (C) 2014 Red Hat Inc. | |
5 | * Authors: | |
6 | * Vivek Goyal <vgoyal@redhat.com> | |
7 | * | |
8 | * This source code is licensed under the GNU General Public License, | |
9 | * Version 2. See the file COPYING for more details. | |
10 | */ | |
11 | ||
12 | #include <linux/capability.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/file.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/kexec.h> | |
17 | #include <linux/mutex.h> | |
18 | #include <linux/list.h> | |
19 | #include <crypto/hash.h> | |
20 | #include <crypto/sha.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/vmalloc.h> | |
23 | #include "kexec_internal.h" | |
24 | ||
25 | /* | |
26 | * Declare these symbols weak so that if architecture provides a purgatory, | |
27 | * these will be overridden. | |
28 | */ | |
29 | char __weak kexec_purgatory[0]; | |
30 | size_t __weak kexec_purgatory_size = 0; | |
31 | ||
32 | static int kexec_calculate_store_digests(struct kimage *image); | |
33 | ||
34 | static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len) | |
35 | { | |
36 | struct fd f = fdget(fd); | |
37 | int ret; | |
38 | struct kstat stat; | |
39 | loff_t pos; | |
40 | ssize_t bytes = 0; | |
41 | ||
42 | if (!f.file) | |
43 | return -EBADF; | |
44 | ||
45 | ret = vfs_getattr(&f.file->f_path, &stat); | |
46 | if (ret) | |
47 | goto out; | |
48 | ||
49 | if (stat.size > INT_MAX) { | |
50 | ret = -EFBIG; | |
51 | goto out; | |
52 | } | |
53 | ||
54 | /* Don't hand 0 to vmalloc, it whines. */ | |
55 | if (stat.size == 0) { | |
56 | ret = -EINVAL; | |
57 | goto out; | |
58 | } | |
59 | ||
60 | *buf = vmalloc(stat.size); | |
61 | if (!*buf) { | |
62 | ret = -ENOMEM; | |
63 | goto out; | |
64 | } | |
65 | ||
66 | pos = 0; | |
67 | while (pos < stat.size) { | |
68 | bytes = kernel_read(f.file, pos, (char *)(*buf) + pos, | |
69 | stat.size - pos); | |
70 | if (bytes < 0) { | |
71 | vfree(*buf); | |
72 | ret = bytes; | |
73 | goto out; | |
74 | } | |
75 | ||
76 | if (bytes == 0) | |
77 | break; | |
78 | pos += bytes; | |
79 | } | |
80 | ||
81 | if (pos != stat.size) { | |
82 | ret = -EBADF; | |
83 | vfree(*buf); | |
84 | goto out; | |
85 | } | |
86 | ||
87 | *buf_len = pos; | |
88 | out: | |
89 | fdput(f); | |
90 | return ret; | |
91 | } | |
92 | ||
93 | /* Architectures can provide this probe function */ | |
94 | int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, | |
95 | unsigned long buf_len) | |
96 | { | |
97 | return -ENOEXEC; | |
98 | } | |
99 | ||
100 | void * __weak arch_kexec_kernel_image_load(struct kimage *image) | |
101 | { | |
102 | return ERR_PTR(-ENOEXEC); | |
103 | } | |
104 | ||
105 | int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) | |
106 | { | |
107 | return -EINVAL; | |
108 | } | |
109 | ||
110 | int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, | |
111 | unsigned long buf_len) | |
112 | { | |
113 | return -EKEYREJECTED; | |
114 | } | |
115 | ||
116 | /* Apply relocations of type RELA */ | |
117 | int __weak | |
118 | arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
119 | unsigned int relsec) | |
120 | { | |
121 | pr_err("RELA relocation unsupported.\n"); | |
122 | return -ENOEXEC; | |
123 | } | |
124 | ||
125 | /* Apply relocations of type REL */ | |
126 | int __weak | |
127 | arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
128 | unsigned int relsec) | |
129 | { | |
130 | pr_err("REL relocation unsupported.\n"); | |
131 | return -ENOEXEC; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Free up memory used by kernel, initrd, and command line. This is temporary | |
136 | * memory allocation which is not needed any more after these buffers have | |
137 | * been loaded into separate segments and have been copied elsewhere. | |
138 | */ | |
139 | void kimage_file_post_load_cleanup(struct kimage *image) | |
140 | { | |
141 | struct purgatory_info *pi = &image->purgatory_info; | |
142 | ||
143 | vfree(image->kernel_buf); | |
144 | image->kernel_buf = NULL; | |
145 | ||
146 | vfree(image->initrd_buf); | |
147 | image->initrd_buf = NULL; | |
148 | ||
149 | kfree(image->cmdline_buf); | |
150 | image->cmdline_buf = NULL; | |
151 | ||
152 | vfree(pi->purgatory_buf); | |
153 | pi->purgatory_buf = NULL; | |
154 | ||
155 | vfree(pi->sechdrs); | |
156 | pi->sechdrs = NULL; | |
157 | ||
158 | /* See if architecture has anything to cleanup post load */ | |
159 | arch_kimage_file_post_load_cleanup(image); | |
160 | ||
161 | /* | |
162 | * Above call should have called into bootloader to free up | |
163 | * any data stored in kimage->image_loader_data. It should | |
164 | * be ok now to free it up. | |
165 | */ | |
166 | kfree(image->image_loader_data); | |
167 | image->image_loader_data = NULL; | |
168 | } | |
169 | ||
170 | /* | |
171 | * In file mode list of segments is prepared by kernel. Copy relevant | |
172 | * data from user space, do error checking, prepare segment list | |
173 | */ | |
174 | static int | |
175 | kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, | |
176 | const char __user *cmdline_ptr, | |
177 | unsigned long cmdline_len, unsigned flags) | |
178 | { | |
179 | int ret = 0; | |
180 | void *ldata; | |
181 | ||
182 | ret = copy_file_from_fd(kernel_fd, &image->kernel_buf, | |
183 | &image->kernel_buf_len); | |
184 | if (ret) | |
185 | return ret; | |
186 | ||
187 | /* Call arch image probe handlers */ | |
188 | ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, | |
189 | image->kernel_buf_len); | |
190 | ||
191 | if (ret) | |
192 | goto out; | |
193 | ||
194 | #ifdef CONFIG_KEXEC_VERIFY_SIG | |
195 | ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, | |
196 | image->kernel_buf_len); | |
197 | if (ret) { | |
198 | pr_debug("kernel signature verification failed.\n"); | |
199 | goto out; | |
200 | } | |
201 | pr_debug("kernel signature verification successful.\n"); | |
202 | #endif | |
203 | /* It is possible that there no initramfs is being loaded */ | |
204 | if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { | |
205 | ret = copy_file_from_fd(initrd_fd, &image->initrd_buf, | |
206 | &image->initrd_buf_len); | |
207 | if (ret) | |
208 | goto out; | |
209 | } | |
210 | ||
211 | if (cmdline_len) { | |
212 | image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL); | |
213 | if (!image->cmdline_buf) { | |
214 | ret = -ENOMEM; | |
215 | goto out; | |
216 | } | |
217 | ||
218 | ret = copy_from_user(image->cmdline_buf, cmdline_ptr, | |
219 | cmdline_len); | |
220 | if (ret) { | |
221 | ret = -EFAULT; | |
222 | goto out; | |
223 | } | |
224 | ||
225 | image->cmdline_buf_len = cmdline_len; | |
226 | ||
227 | /* command line should be a string with last byte null */ | |
228 | if (image->cmdline_buf[cmdline_len - 1] != '\0') { | |
229 | ret = -EINVAL; | |
230 | goto out; | |
231 | } | |
232 | } | |
233 | ||
234 | /* Call arch image load handlers */ | |
235 | ldata = arch_kexec_kernel_image_load(image); | |
236 | ||
237 | if (IS_ERR(ldata)) { | |
238 | ret = PTR_ERR(ldata); | |
239 | goto out; | |
240 | } | |
241 | ||
242 | image->image_loader_data = ldata; | |
243 | out: | |
244 | /* In case of error, free up all allocated memory in this function */ | |
245 | if (ret) | |
246 | kimage_file_post_load_cleanup(image); | |
247 | return ret; | |
248 | } | |
249 | ||
250 | static int | |
251 | kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, | |
252 | int initrd_fd, const char __user *cmdline_ptr, | |
253 | unsigned long cmdline_len, unsigned long flags) | |
254 | { | |
255 | int ret; | |
256 | struct kimage *image; | |
257 | bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; | |
258 | ||
259 | image = do_kimage_alloc_init(); | |
260 | if (!image) | |
261 | return -ENOMEM; | |
262 | ||
263 | image->file_mode = 1; | |
264 | ||
265 | if (kexec_on_panic) { | |
266 | /* Enable special crash kernel control page alloc policy. */ | |
267 | image->control_page = crashk_res.start; | |
268 | image->type = KEXEC_TYPE_CRASH; | |
269 | } | |
270 | ||
271 | ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, | |
272 | cmdline_ptr, cmdline_len, flags); | |
273 | if (ret) | |
274 | goto out_free_image; | |
275 | ||
276 | ret = sanity_check_segment_list(image); | |
277 | if (ret) | |
278 | goto out_free_post_load_bufs; | |
279 | ||
280 | ret = -ENOMEM; | |
281 | image->control_code_page = kimage_alloc_control_pages(image, | |
282 | get_order(KEXEC_CONTROL_PAGE_SIZE)); | |
283 | if (!image->control_code_page) { | |
284 | pr_err("Could not allocate control_code_buffer\n"); | |
285 | goto out_free_post_load_bufs; | |
286 | } | |
287 | ||
288 | if (!kexec_on_panic) { | |
289 | image->swap_page = kimage_alloc_control_pages(image, 0); | |
290 | if (!image->swap_page) { | |
291 | pr_err("Could not allocate swap buffer\n"); | |
292 | goto out_free_control_pages; | |
293 | } | |
294 | } | |
295 | ||
296 | *rimage = image; | |
297 | return 0; | |
298 | out_free_control_pages: | |
299 | kimage_free_page_list(&image->control_pages); | |
300 | out_free_post_load_bufs: | |
301 | kimage_file_post_load_cleanup(image); | |
302 | out_free_image: | |
303 | kfree(image); | |
304 | return ret; | |
305 | } | |
306 | ||
307 | SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, | |
308 | unsigned long, cmdline_len, const char __user *, cmdline_ptr, | |
309 | unsigned long, flags) | |
310 | { | |
311 | int ret = 0, i; | |
312 | struct kimage **dest_image, *image; | |
313 | ||
314 | /* We only trust the superuser with rebooting the system. */ | |
315 | if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) | |
316 | return -EPERM; | |
317 | ||
318 | /* Make sure we have a legal set of flags */ | |
319 | if (flags != (flags & KEXEC_FILE_FLAGS)) | |
320 | return -EINVAL; | |
321 | ||
322 | image = NULL; | |
323 | ||
324 | if (!mutex_trylock(&kexec_mutex)) | |
325 | return -EBUSY; | |
326 | ||
327 | dest_image = &kexec_image; | |
328 | if (flags & KEXEC_FILE_ON_CRASH) | |
329 | dest_image = &kexec_crash_image; | |
330 | ||
331 | if (flags & KEXEC_FILE_UNLOAD) | |
332 | goto exchange; | |
333 | ||
334 | /* | |
335 | * In case of crash, new kernel gets loaded in reserved region. It is | |
336 | * same memory where old crash kernel might be loaded. Free any | |
337 | * current crash dump kernel before we corrupt it. | |
338 | */ | |
339 | if (flags & KEXEC_FILE_ON_CRASH) | |
340 | kimage_free(xchg(&kexec_crash_image, NULL)); | |
341 | ||
342 | ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, | |
343 | cmdline_len, flags); | |
344 | if (ret) | |
345 | goto out; | |
346 | ||
347 | ret = machine_kexec_prepare(image); | |
348 | if (ret) | |
349 | goto out; | |
350 | ||
351 | ret = kexec_calculate_store_digests(image); | |
352 | if (ret) | |
353 | goto out; | |
354 | ||
355 | for (i = 0; i < image->nr_segments; i++) { | |
356 | struct kexec_segment *ksegment; | |
357 | ||
358 | ksegment = &image->segment[i]; | |
359 | pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", | |
360 | i, ksegment->buf, ksegment->bufsz, ksegment->mem, | |
361 | ksegment->memsz); | |
362 | ||
363 | ret = kimage_load_segment(image, &image->segment[i]); | |
364 | if (ret) | |
365 | goto out; | |
366 | } | |
367 | ||
368 | kimage_terminate(image); | |
369 | ||
370 | /* | |
371 | * Free up any temporary buffers allocated which are not needed | |
372 | * after image has been loaded | |
373 | */ | |
374 | kimage_file_post_load_cleanup(image); | |
375 | exchange: | |
376 | image = xchg(dest_image, image); | |
377 | out: | |
378 | mutex_unlock(&kexec_mutex); | |
379 | kimage_free(image); | |
380 | return ret; | |
381 | } | |
382 | ||
383 | static int locate_mem_hole_top_down(unsigned long start, unsigned long end, | |
384 | struct kexec_buf *kbuf) | |
385 | { | |
386 | struct kimage *image = kbuf->image; | |
387 | unsigned long temp_start, temp_end; | |
388 | ||
389 | temp_end = min(end, kbuf->buf_max); | |
390 | temp_start = temp_end - kbuf->memsz; | |
391 | ||
392 | do { | |
393 | /* align down start */ | |
394 | temp_start = temp_start & (~(kbuf->buf_align - 1)); | |
395 | ||
396 | if (temp_start < start || temp_start < kbuf->buf_min) | |
397 | return 0; | |
398 | ||
399 | temp_end = temp_start + kbuf->memsz - 1; | |
400 | ||
401 | /* | |
402 | * Make sure this does not conflict with any of existing | |
403 | * segments | |
404 | */ | |
405 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
406 | temp_start = temp_start - PAGE_SIZE; | |
407 | continue; | |
408 | } | |
409 | ||
410 | /* We found a suitable memory range */ | |
411 | break; | |
412 | } while (1); | |
413 | ||
414 | /* If we are here, we found a suitable memory range */ | |
415 | kbuf->mem = temp_start; | |
416 | ||
417 | /* Success, stop navigating through remaining System RAM ranges */ | |
418 | return 1; | |
419 | } | |
420 | ||
421 | static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, | |
422 | struct kexec_buf *kbuf) | |
423 | { | |
424 | struct kimage *image = kbuf->image; | |
425 | unsigned long temp_start, temp_end; | |
426 | ||
427 | temp_start = max(start, kbuf->buf_min); | |
428 | ||
429 | do { | |
430 | temp_start = ALIGN(temp_start, kbuf->buf_align); | |
431 | temp_end = temp_start + kbuf->memsz - 1; | |
432 | ||
433 | if (temp_end > end || temp_end > kbuf->buf_max) | |
434 | return 0; | |
435 | /* | |
436 | * Make sure this does not conflict with any of existing | |
437 | * segments | |
438 | */ | |
439 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
440 | temp_start = temp_start + PAGE_SIZE; | |
441 | continue; | |
442 | } | |
443 | ||
444 | /* We found a suitable memory range */ | |
445 | break; | |
446 | } while (1); | |
447 | ||
448 | /* If we are here, we found a suitable memory range */ | |
449 | kbuf->mem = temp_start; | |
450 | ||
451 | /* Success, stop navigating through remaining System RAM ranges */ | |
452 | return 1; | |
453 | } | |
454 | ||
455 | static int locate_mem_hole_callback(u64 start, u64 end, void *arg) | |
456 | { | |
457 | struct kexec_buf *kbuf = (struct kexec_buf *)arg; | |
458 | unsigned long sz = end - start + 1; | |
459 | ||
460 | /* Returning 0 will take to next memory range */ | |
461 | if (sz < kbuf->memsz) | |
462 | return 0; | |
463 | ||
464 | if (end < kbuf->buf_min || start > kbuf->buf_max) | |
465 | return 0; | |
466 | ||
467 | /* | |
468 | * Allocate memory top down with-in ram range. Otherwise bottom up | |
469 | * allocation. | |
470 | */ | |
471 | if (kbuf->top_down) | |
472 | return locate_mem_hole_top_down(start, end, kbuf); | |
473 | return locate_mem_hole_bottom_up(start, end, kbuf); | |
474 | } | |
475 | ||
476 | /* | |
477 | * Helper function for placing a buffer in a kexec segment. This assumes | |
478 | * that kexec_mutex is held. | |
479 | */ | |
480 | int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz, | |
481 | unsigned long memsz, unsigned long buf_align, | |
482 | unsigned long buf_min, unsigned long buf_max, | |
483 | bool top_down, unsigned long *load_addr) | |
484 | { | |
485 | ||
486 | struct kexec_segment *ksegment; | |
487 | struct kexec_buf buf, *kbuf; | |
488 | int ret; | |
489 | ||
490 | /* Currently adding segment this way is allowed only in file mode */ | |
491 | if (!image->file_mode) | |
492 | return -EINVAL; | |
493 | ||
494 | if (image->nr_segments >= KEXEC_SEGMENT_MAX) | |
495 | return -EINVAL; | |
496 | ||
497 | /* | |
498 | * Make sure we are not trying to add buffer after allocating | |
499 | * control pages. All segments need to be placed first before | |
500 | * any control pages are allocated. As control page allocation | |
501 | * logic goes through list of segments to make sure there are | |
502 | * no destination overlaps. | |
503 | */ | |
504 | if (!list_empty(&image->control_pages)) { | |
505 | WARN_ON(1); | |
506 | return -EINVAL; | |
507 | } | |
508 | ||
509 | memset(&buf, 0, sizeof(struct kexec_buf)); | |
510 | kbuf = &buf; | |
511 | kbuf->image = image; | |
512 | kbuf->buffer = buffer; | |
513 | kbuf->bufsz = bufsz; | |
514 | ||
515 | kbuf->memsz = ALIGN(memsz, PAGE_SIZE); | |
516 | kbuf->buf_align = max(buf_align, PAGE_SIZE); | |
517 | kbuf->buf_min = buf_min; | |
518 | kbuf->buf_max = buf_max; | |
519 | kbuf->top_down = top_down; | |
520 | ||
521 | /* Walk the RAM ranges and allocate a suitable range for the buffer */ | |
522 | if (image->type == KEXEC_TYPE_CRASH) | |
523 | ret = walk_iomem_res("Crash kernel", | |
524 | IORESOURCE_MEM | IORESOURCE_BUSY, | |
525 | crashk_res.start, crashk_res.end, kbuf, | |
526 | locate_mem_hole_callback); | |
527 | else | |
528 | ret = walk_system_ram_res(0, -1, kbuf, | |
529 | locate_mem_hole_callback); | |
530 | if (ret != 1) { | |
531 | /* A suitable memory range could not be found for buffer */ | |
532 | return -EADDRNOTAVAIL; | |
533 | } | |
534 | ||
535 | /* Found a suitable memory range */ | |
536 | ksegment = &image->segment[image->nr_segments]; | |
537 | ksegment->kbuf = kbuf->buffer; | |
538 | ksegment->bufsz = kbuf->bufsz; | |
539 | ksegment->mem = kbuf->mem; | |
540 | ksegment->memsz = kbuf->memsz; | |
541 | image->nr_segments++; | |
542 | *load_addr = ksegment->mem; | |
543 | return 0; | |
544 | } | |
545 | ||
546 | /* Calculate and store the digest of segments */ | |
547 | static int kexec_calculate_store_digests(struct kimage *image) | |
548 | { | |
549 | struct crypto_shash *tfm; | |
550 | struct shash_desc *desc; | |
551 | int ret = 0, i, j, zero_buf_sz, sha_region_sz; | |
552 | size_t desc_size, nullsz; | |
553 | char *digest; | |
554 | void *zero_buf; | |
555 | struct kexec_sha_region *sha_regions; | |
556 | struct purgatory_info *pi = &image->purgatory_info; | |
557 | ||
558 | zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); | |
559 | zero_buf_sz = PAGE_SIZE; | |
560 | ||
561 | tfm = crypto_alloc_shash("sha256", 0, 0); | |
562 | if (IS_ERR(tfm)) { | |
563 | ret = PTR_ERR(tfm); | |
564 | goto out; | |
565 | } | |
566 | ||
567 | desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); | |
568 | desc = kzalloc(desc_size, GFP_KERNEL); | |
569 | if (!desc) { | |
570 | ret = -ENOMEM; | |
571 | goto out_free_tfm; | |
572 | } | |
573 | ||
574 | sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); | |
575 | sha_regions = vzalloc(sha_region_sz); | |
576 | if (!sha_regions) | |
577 | goto out_free_desc; | |
578 | ||
579 | desc->tfm = tfm; | |
580 | desc->flags = 0; | |
581 | ||
582 | ret = crypto_shash_init(desc); | |
583 | if (ret < 0) | |
584 | goto out_free_sha_regions; | |
585 | ||
586 | digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); | |
587 | if (!digest) { | |
588 | ret = -ENOMEM; | |
589 | goto out_free_sha_regions; | |
590 | } | |
591 | ||
592 | for (j = i = 0; i < image->nr_segments; i++) { | |
593 | struct kexec_segment *ksegment; | |
594 | ||
595 | ksegment = &image->segment[i]; | |
596 | /* | |
597 | * Skip purgatory as it will be modified once we put digest | |
598 | * info in purgatory. | |
599 | */ | |
600 | if (ksegment->kbuf == pi->purgatory_buf) | |
601 | continue; | |
602 | ||
603 | ret = crypto_shash_update(desc, ksegment->kbuf, | |
604 | ksegment->bufsz); | |
605 | if (ret) | |
606 | break; | |
607 | ||
608 | /* | |
609 | * Assume rest of the buffer is filled with zero and | |
610 | * update digest accordingly. | |
611 | */ | |
612 | nullsz = ksegment->memsz - ksegment->bufsz; | |
613 | while (nullsz) { | |
614 | unsigned long bytes = nullsz; | |
615 | ||
616 | if (bytes > zero_buf_sz) | |
617 | bytes = zero_buf_sz; | |
618 | ret = crypto_shash_update(desc, zero_buf, bytes); | |
619 | if (ret) | |
620 | break; | |
621 | nullsz -= bytes; | |
622 | } | |
623 | ||
624 | if (ret) | |
625 | break; | |
626 | ||
627 | sha_regions[j].start = ksegment->mem; | |
628 | sha_regions[j].len = ksegment->memsz; | |
629 | j++; | |
630 | } | |
631 | ||
632 | if (!ret) { | |
633 | ret = crypto_shash_final(desc, digest); | |
634 | if (ret) | |
635 | goto out_free_digest; | |
636 | ret = kexec_purgatory_get_set_symbol(image, "sha_regions", | |
637 | sha_regions, sha_region_sz, 0); | |
638 | if (ret) | |
639 | goto out_free_digest; | |
640 | ||
641 | ret = kexec_purgatory_get_set_symbol(image, "sha256_digest", | |
642 | digest, SHA256_DIGEST_SIZE, 0); | |
643 | if (ret) | |
644 | goto out_free_digest; | |
645 | } | |
646 | ||
647 | out_free_digest: | |
648 | kfree(digest); | |
649 | out_free_sha_regions: | |
650 | vfree(sha_regions); | |
651 | out_free_desc: | |
652 | kfree(desc); | |
653 | out_free_tfm: | |
654 | kfree(tfm); | |
655 | out: | |
656 | return ret; | |
657 | } | |
658 | ||
659 | /* Actually load purgatory. Lot of code taken from kexec-tools */ | |
660 | static int __kexec_load_purgatory(struct kimage *image, unsigned long min, | |
661 | unsigned long max, int top_down) | |
662 | { | |
663 | struct purgatory_info *pi = &image->purgatory_info; | |
664 | unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad; | |
665 | unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset; | |
666 | unsigned char *buf_addr, *src; | |
667 | int i, ret = 0, entry_sidx = -1; | |
668 | const Elf_Shdr *sechdrs_c; | |
669 | Elf_Shdr *sechdrs = NULL; | |
670 | void *purgatory_buf = NULL; | |
671 | ||
672 | /* | |
673 | * sechdrs_c points to section headers in purgatory and are read | |
674 | * only. No modifications allowed. | |
675 | */ | |
676 | sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff; | |
677 | ||
678 | /* | |
679 | * We can not modify sechdrs_c[] and its fields. It is read only. | |
680 | * Copy it over to a local copy where one can store some temporary | |
681 | * data and free it at the end. We need to modify ->sh_addr and | |
682 | * ->sh_offset fields to keep track of permanent and temporary | |
683 | * locations of sections. | |
684 | */ | |
685 | sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
686 | if (!sechdrs) | |
687 | return -ENOMEM; | |
688 | ||
689 | memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
690 | ||
691 | /* | |
692 | * We seem to have multiple copies of sections. First copy is which | |
693 | * is embedded in kernel in read only section. Some of these sections | |
694 | * will be copied to a temporary buffer and relocated. And these | |
695 | * sections will finally be copied to their final destination at | |
696 | * segment load time. | |
697 | * | |
698 | * Use ->sh_offset to reflect section address in memory. It will | |
699 | * point to original read only copy if section is not allocatable. | |
700 | * Otherwise it will point to temporary copy which will be relocated. | |
701 | * | |
702 | * Use ->sh_addr to contain final address of the section where it | |
703 | * will go during execution time. | |
704 | */ | |
705 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
706 | if (sechdrs[i].sh_type == SHT_NOBITS) | |
707 | continue; | |
708 | ||
709 | sechdrs[i].sh_offset = (unsigned long)pi->ehdr + | |
710 | sechdrs[i].sh_offset; | |
711 | } | |
712 | ||
713 | /* | |
714 | * Identify entry point section and make entry relative to section | |
715 | * start. | |
716 | */ | |
717 | entry = pi->ehdr->e_entry; | |
718 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
719 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
720 | continue; | |
721 | ||
722 | if (!(sechdrs[i].sh_flags & SHF_EXECINSTR)) | |
723 | continue; | |
724 | ||
725 | /* Make entry section relative */ | |
726 | if (sechdrs[i].sh_addr <= pi->ehdr->e_entry && | |
727 | ((sechdrs[i].sh_addr + sechdrs[i].sh_size) > | |
728 | pi->ehdr->e_entry)) { | |
729 | entry_sidx = i; | |
730 | entry -= sechdrs[i].sh_addr; | |
731 | break; | |
732 | } | |
733 | } | |
734 | ||
735 | /* Determine how much memory is needed to load relocatable object. */ | |
736 | buf_align = 1; | |
737 | bss_align = 1; | |
738 | buf_sz = 0; | |
739 | bss_sz = 0; | |
740 | ||
741 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
742 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
743 | continue; | |
744 | ||
745 | align = sechdrs[i].sh_addralign; | |
746 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
747 | if (buf_align < align) | |
748 | buf_align = align; | |
749 | buf_sz = ALIGN(buf_sz, align); | |
750 | buf_sz += sechdrs[i].sh_size; | |
751 | } else { | |
752 | /* bss section */ | |
753 | if (bss_align < align) | |
754 | bss_align = align; | |
755 | bss_sz = ALIGN(bss_sz, align); | |
756 | bss_sz += sechdrs[i].sh_size; | |
757 | } | |
758 | } | |
759 | ||
760 | /* Determine the bss padding required to align bss properly */ | |
761 | bss_pad = 0; | |
762 | if (buf_sz & (bss_align - 1)) | |
763 | bss_pad = bss_align - (buf_sz & (bss_align - 1)); | |
764 | ||
765 | memsz = buf_sz + bss_pad + bss_sz; | |
766 | ||
767 | /* Allocate buffer for purgatory */ | |
768 | purgatory_buf = vzalloc(buf_sz); | |
769 | if (!purgatory_buf) { | |
770 | ret = -ENOMEM; | |
771 | goto out; | |
772 | } | |
773 | ||
774 | if (buf_align < bss_align) | |
775 | buf_align = bss_align; | |
776 | ||
777 | /* Add buffer to segment list */ | |
778 | ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz, | |
779 | buf_align, min, max, top_down, | |
780 | &pi->purgatory_load_addr); | |
781 | if (ret) | |
782 | goto out; | |
783 | ||
784 | /* Load SHF_ALLOC sections */ | |
785 | buf_addr = purgatory_buf; | |
786 | load_addr = curr_load_addr = pi->purgatory_load_addr; | |
787 | bss_addr = load_addr + buf_sz + bss_pad; | |
788 | ||
789 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
790 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
791 | continue; | |
792 | ||
793 | align = sechdrs[i].sh_addralign; | |
794 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
795 | curr_load_addr = ALIGN(curr_load_addr, align); | |
796 | offset = curr_load_addr - load_addr; | |
797 | /* We already modifed ->sh_offset to keep src addr */ | |
798 | src = (char *) sechdrs[i].sh_offset; | |
799 | memcpy(buf_addr + offset, src, sechdrs[i].sh_size); | |
800 | ||
801 | /* Store load address and source address of section */ | |
802 | sechdrs[i].sh_addr = curr_load_addr; | |
803 | ||
804 | /* | |
805 | * This section got copied to temporary buffer. Update | |
806 | * ->sh_offset accordingly. | |
807 | */ | |
808 | sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset); | |
809 | ||
810 | /* Advance to the next address */ | |
811 | curr_load_addr += sechdrs[i].sh_size; | |
812 | } else { | |
813 | bss_addr = ALIGN(bss_addr, align); | |
814 | sechdrs[i].sh_addr = bss_addr; | |
815 | bss_addr += sechdrs[i].sh_size; | |
816 | } | |
817 | } | |
818 | ||
819 | /* Update entry point based on load address of text section */ | |
820 | if (entry_sidx >= 0) | |
821 | entry += sechdrs[entry_sidx].sh_addr; | |
822 | ||
823 | /* Make kernel jump to purgatory after shutdown */ | |
824 | image->start = entry; | |
825 | ||
826 | /* Used later to get/set symbol values */ | |
827 | pi->sechdrs = sechdrs; | |
828 | ||
829 | /* | |
830 | * Used later to identify which section is purgatory and skip it | |
831 | * from checksumming. | |
832 | */ | |
833 | pi->purgatory_buf = purgatory_buf; | |
834 | return ret; | |
835 | out: | |
836 | vfree(sechdrs); | |
837 | vfree(purgatory_buf); | |
838 | return ret; | |
839 | } | |
840 | ||
841 | static int kexec_apply_relocations(struct kimage *image) | |
842 | { | |
843 | int i, ret; | |
844 | struct purgatory_info *pi = &image->purgatory_info; | |
845 | Elf_Shdr *sechdrs = pi->sechdrs; | |
846 | ||
847 | /* Apply relocations */ | |
848 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
849 | Elf_Shdr *section, *symtab; | |
850 | ||
851 | if (sechdrs[i].sh_type != SHT_RELA && | |
852 | sechdrs[i].sh_type != SHT_REL) | |
853 | continue; | |
854 | ||
855 | /* | |
856 | * For section of type SHT_RELA/SHT_REL, | |
857 | * ->sh_link contains section header index of associated | |
858 | * symbol table. And ->sh_info contains section header | |
859 | * index of section to which relocations apply. | |
860 | */ | |
861 | if (sechdrs[i].sh_info >= pi->ehdr->e_shnum || | |
862 | sechdrs[i].sh_link >= pi->ehdr->e_shnum) | |
863 | return -ENOEXEC; | |
864 | ||
865 | section = &sechdrs[sechdrs[i].sh_info]; | |
866 | symtab = &sechdrs[sechdrs[i].sh_link]; | |
867 | ||
868 | if (!(section->sh_flags & SHF_ALLOC)) | |
869 | continue; | |
870 | ||
871 | /* | |
872 | * symtab->sh_link contain section header index of associated | |
873 | * string table. | |
874 | */ | |
875 | if (symtab->sh_link >= pi->ehdr->e_shnum) | |
876 | /* Invalid section number? */ | |
877 | continue; | |
878 | ||
879 | /* | |
880 | * Respective architecture needs to provide support for applying | |
881 | * relocations of type SHT_RELA/SHT_REL. | |
882 | */ | |
883 | if (sechdrs[i].sh_type == SHT_RELA) | |
884 | ret = arch_kexec_apply_relocations_add(pi->ehdr, | |
885 | sechdrs, i); | |
886 | else if (sechdrs[i].sh_type == SHT_REL) | |
887 | ret = arch_kexec_apply_relocations(pi->ehdr, | |
888 | sechdrs, i); | |
889 | if (ret) | |
890 | return ret; | |
891 | } | |
892 | ||
893 | return 0; | |
894 | } | |
895 | ||
896 | /* Load relocatable purgatory object and relocate it appropriately */ | |
897 | int kexec_load_purgatory(struct kimage *image, unsigned long min, | |
898 | unsigned long max, int top_down, | |
899 | unsigned long *load_addr) | |
900 | { | |
901 | struct purgatory_info *pi = &image->purgatory_info; | |
902 | int ret; | |
903 | ||
904 | if (kexec_purgatory_size <= 0) | |
905 | return -EINVAL; | |
906 | ||
907 | if (kexec_purgatory_size < sizeof(Elf_Ehdr)) | |
908 | return -ENOEXEC; | |
909 | ||
910 | pi->ehdr = (Elf_Ehdr *)kexec_purgatory; | |
911 | ||
912 | if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0 | |
913 | || pi->ehdr->e_type != ET_REL | |
914 | || !elf_check_arch(pi->ehdr) | |
915 | || pi->ehdr->e_shentsize != sizeof(Elf_Shdr)) | |
916 | return -ENOEXEC; | |
917 | ||
918 | if (pi->ehdr->e_shoff >= kexec_purgatory_size | |
919 | || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) > | |
920 | kexec_purgatory_size - pi->ehdr->e_shoff)) | |
921 | return -ENOEXEC; | |
922 | ||
923 | ret = __kexec_load_purgatory(image, min, max, top_down); | |
924 | if (ret) | |
925 | return ret; | |
926 | ||
927 | ret = kexec_apply_relocations(image); | |
928 | if (ret) | |
929 | goto out; | |
930 | ||
931 | *load_addr = pi->purgatory_load_addr; | |
932 | return 0; | |
933 | out: | |
934 | vfree(pi->sechdrs); | |
935 | vfree(pi->purgatory_buf); | |
936 | return ret; | |
937 | } | |
938 | ||
939 | static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, | |
940 | const char *name) | |
941 | { | |
942 | Elf_Sym *syms; | |
943 | Elf_Shdr *sechdrs; | |
944 | Elf_Ehdr *ehdr; | |
945 | int i, k; | |
946 | const char *strtab; | |
947 | ||
948 | if (!pi->sechdrs || !pi->ehdr) | |
949 | return NULL; | |
950 | ||
951 | sechdrs = pi->sechdrs; | |
952 | ehdr = pi->ehdr; | |
953 | ||
954 | for (i = 0; i < ehdr->e_shnum; i++) { | |
955 | if (sechdrs[i].sh_type != SHT_SYMTAB) | |
956 | continue; | |
957 | ||
958 | if (sechdrs[i].sh_link >= ehdr->e_shnum) | |
959 | /* Invalid strtab section number */ | |
960 | continue; | |
961 | strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset; | |
962 | syms = (Elf_Sym *)sechdrs[i].sh_offset; | |
963 | ||
964 | /* Go through symbols for a match */ | |
965 | for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { | |
966 | if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) | |
967 | continue; | |
968 | ||
969 | if (strcmp(strtab + syms[k].st_name, name) != 0) | |
970 | continue; | |
971 | ||
972 | if (syms[k].st_shndx == SHN_UNDEF || | |
973 | syms[k].st_shndx >= ehdr->e_shnum) { | |
974 | pr_debug("Symbol: %s has bad section index %d.\n", | |
975 | name, syms[k].st_shndx); | |
976 | return NULL; | |
977 | } | |
978 | ||
979 | /* Found the symbol we are looking for */ | |
980 | return &syms[k]; | |
981 | } | |
982 | } | |
983 | ||
984 | return NULL; | |
985 | } | |
986 | ||
987 | void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) | |
988 | { | |
989 | struct purgatory_info *pi = &image->purgatory_info; | |
990 | Elf_Sym *sym; | |
991 | Elf_Shdr *sechdr; | |
992 | ||
993 | sym = kexec_purgatory_find_symbol(pi, name); | |
994 | if (!sym) | |
995 | return ERR_PTR(-EINVAL); | |
996 | ||
997 | sechdr = &pi->sechdrs[sym->st_shndx]; | |
998 | ||
999 | /* | |
1000 | * Returns the address where symbol will finally be loaded after | |
1001 | * kexec_load_segment() | |
1002 | */ | |
1003 | return (void *)(sechdr->sh_addr + sym->st_value); | |
1004 | } | |
1005 | ||
1006 | /* | |
1007 | * Get or set value of a symbol. If "get_value" is true, symbol value is | |
1008 | * returned in buf otherwise symbol value is set based on value in buf. | |
1009 | */ | |
1010 | int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, | |
1011 | void *buf, unsigned int size, bool get_value) | |
1012 | { | |
1013 | Elf_Sym *sym; | |
1014 | Elf_Shdr *sechdrs; | |
1015 | struct purgatory_info *pi = &image->purgatory_info; | |
1016 | char *sym_buf; | |
1017 | ||
1018 | sym = kexec_purgatory_find_symbol(pi, name); | |
1019 | if (!sym) | |
1020 | return -EINVAL; | |
1021 | ||
1022 | if (sym->st_size != size) { | |
1023 | pr_err("symbol %s size mismatch: expected %lu actual %u\n", | |
1024 | name, (unsigned long)sym->st_size, size); | |
1025 | return -EINVAL; | |
1026 | } | |
1027 | ||
1028 | sechdrs = pi->sechdrs; | |
1029 | ||
1030 | if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) { | |
1031 | pr_err("symbol %s is in a bss section. Cannot %s\n", name, | |
1032 | get_value ? "get" : "set"); | |
1033 | return -EINVAL; | |
1034 | } | |
1035 | ||
1036 | sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset + | |
1037 | sym->st_value; | |
1038 | ||
1039 | if (get_value) | |
1040 | memcpy((void *)buf, sym_buf, size); | |
1041 | else | |
1042 | memcpy((void *)sym_buf, buf, size); | |
1043 | ||
1044 | return 0; | |
1045 | } |