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a43cac0d DY |
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 | ||
de90a6bc MH |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
a43cac0d DY |
14 | #include <linux/capability.h> |
15 | #include <linux/mm.h> | |
16 | #include <linux/file.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/kexec.h> | |
19 | #include <linux/mutex.h> | |
20 | #include <linux/list.h> | |
21 | #include <crypto/hash.h> | |
22 | #include <crypto/sha.h> | |
23 | #include <linux/syscalls.h> | |
24 | #include <linux/vmalloc.h> | |
25 | #include "kexec_internal.h" | |
26 | ||
27 | /* | |
28 | * Declare these symbols weak so that if architecture provides a purgatory, | |
29 | * these will be overridden. | |
30 | */ | |
31 | char __weak kexec_purgatory[0]; | |
32 | size_t __weak kexec_purgatory_size = 0; | |
33 | ||
34 | static int kexec_calculate_store_digests(struct kimage *image); | |
35 | ||
36 | static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len) | |
37 | { | |
38 | struct fd f = fdget(fd); | |
39 | int ret; | |
40 | struct kstat stat; | |
41 | loff_t pos; | |
42 | ssize_t bytes = 0; | |
43 | ||
44 | if (!f.file) | |
45 | return -EBADF; | |
46 | ||
47 | ret = vfs_getattr(&f.file->f_path, &stat); | |
48 | if (ret) | |
49 | goto out; | |
50 | ||
51 | if (stat.size > INT_MAX) { | |
52 | ret = -EFBIG; | |
53 | goto out; | |
54 | } | |
55 | ||
56 | /* Don't hand 0 to vmalloc, it whines. */ | |
57 | if (stat.size == 0) { | |
58 | ret = -EINVAL; | |
59 | goto out; | |
60 | } | |
61 | ||
62 | *buf = vmalloc(stat.size); | |
63 | if (!*buf) { | |
64 | ret = -ENOMEM; | |
65 | goto out; | |
66 | } | |
67 | ||
68 | pos = 0; | |
69 | while (pos < stat.size) { | |
70 | bytes = kernel_read(f.file, pos, (char *)(*buf) + pos, | |
71 | stat.size - pos); | |
72 | if (bytes < 0) { | |
73 | vfree(*buf); | |
74 | ret = bytes; | |
75 | goto out; | |
76 | } | |
77 | ||
78 | if (bytes == 0) | |
79 | break; | |
80 | pos += bytes; | |
81 | } | |
82 | ||
83 | if (pos != stat.size) { | |
84 | ret = -EBADF; | |
85 | vfree(*buf); | |
86 | goto out; | |
87 | } | |
88 | ||
89 | *buf_len = pos; | |
90 | out: | |
91 | fdput(f); | |
92 | return ret; | |
93 | } | |
94 | ||
95 | /* Architectures can provide this probe function */ | |
96 | int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, | |
97 | unsigned long buf_len) | |
98 | { | |
99 | return -ENOEXEC; | |
100 | } | |
101 | ||
102 | void * __weak arch_kexec_kernel_image_load(struct kimage *image) | |
103 | { | |
104 | return ERR_PTR(-ENOEXEC); | |
105 | } | |
106 | ||
107 | int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) | |
108 | { | |
109 | return -EINVAL; | |
110 | } | |
111 | ||
112 | int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, | |
113 | unsigned long buf_len) | |
114 | { | |
115 | return -EKEYREJECTED; | |
116 | } | |
117 | ||
118 | /* Apply relocations of type RELA */ | |
119 | int __weak | |
120 | arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
121 | unsigned int relsec) | |
122 | { | |
123 | pr_err("RELA relocation unsupported.\n"); | |
124 | return -ENOEXEC; | |
125 | } | |
126 | ||
127 | /* Apply relocations of type REL */ | |
128 | int __weak | |
129 | arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
130 | unsigned int relsec) | |
131 | { | |
132 | pr_err("REL relocation unsupported.\n"); | |
133 | return -ENOEXEC; | |
134 | } | |
135 | ||
136 | /* | |
137 | * Free up memory used by kernel, initrd, and command line. This is temporary | |
138 | * memory allocation which is not needed any more after these buffers have | |
139 | * been loaded into separate segments and have been copied elsewhere. | |
140 | */ | |
141 | void kimage_file_post_load_cleanup(struct kimage *image) | |
142 | { | |
143 | struct purgatory_info *pi = &image->purgatory_info; | |
144 | ||
145 | vfree(image->kernel_buf); | |
146 | image->kernel_buf = NULL; | |
147 | ||
148 | vfree(image->initrd_buf); | |
149 | image->initrd_buf = NULL; | |
150 | ||
151 | kfree(image->cmdline_buf); | |
152 | image->cmdline_buf = NULL; | |
153 | ||
154 | vfree(pi->purgatory_buf); | |
155 | pi->purgatory_buf = NULL; | |
156 | ||
157 | vfree(pi->sechdrs); | |
158 | pi->sechdrs = NULL; | |
159 | ||
160 | /* See if architecture has anything to cleanup post load */ | |
161 | arch_kimage_file_post_load_cleanup(image); | |
162 | ||
163 | /* | |
164 | * Above call should have called into bootloader to free up | |
165 | * any data stored in kimage->image_loader_data. It should | |
166 | * be ok now to free it up. | |
167 | */ | |
168 | kfree(image->image_loader_data); | |
169 | image->image_loader_data = NULL; | |
170 | } | |
171 | ||
172 | /* | |
173 | * In file mode list of segments is prepared by kernel. Copy relevant | |
174 | * data from user space, do error checking, prepare segment list | |
175 | */ | |
176 | static int | |
177 | kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, | |
178 | const char __user *cmdline_ptr, | |
179 | unsigned long cmdline_len, unsigned flags) | |
180 | { | |
181 | int ret = 0; | |
182 | void *ldata; | |
183 | ||
184 | ret = copy_file_from_fd(kernel_fd, &image->kernel_buf, | |
185 | &image->kernel_buf_len); | |
186 | if (ret) | |
187 | return ret; | |
188 | ||
189 | /* Call arch image probe handlers */ | |
190 | ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, | |
191 | image->kernel_buf_len); | |
192 | ||
193 | if (ret) | |
194 | goto out; | |
195 | ||
196 | #ifdef CONFIG_KEXEC_VERIFY_SIG | |
197 | ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, | |
198 | image->kernel_buf_len); | |
199 | if (ret) { | |
200 | pr_debug("kernel signature verification failed.\n"); | |
201 | goto out; | |
202 | } | |
203 | pr_debug("kernel signature verification successful.\n"); | |
204 | #endif | |
205 | /* It is possible that there no initramfs is being loaded */ | |
206 | if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { | |
207 | ret = copy_file_from_fd(initrd_fd, &image->initrd_buf, | |
208 | &image->initrd_buf_len); | |
209 | if (ret) | |
210 | goto out; | |
211 | } | |
212 | ||
213 | if (cmdline_len) { | |
214 | image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL); | |
215 | if (!image->cmdline_buf) { | |
216 | ret = -ENOMEM; | |
217 | goto out; | |
218 | } | |
219 | ||
220 | ret = copy_from_user(image->cmdline_buf, cmdline_ptr, | |
221 | cmdline_len); | |
222 | if (ret) { | |
223 | ret = -EFAULT; | |
224 | goto out; | |
225 | } | |
226 | ||
227 | image->cmdline_buf_len = cmdline_len; | |
228 | ||
229 | /* command line should be a string with last byte null */ | |
230 | if (image->cmdline_buf[cmdline_len - 1] != '\0') { | |
231 | ret = -EINVAL; | |
232 | goto out; | |
233 | } | |
234 | } | |
235 | ||
236 | /* Call arch image load handlers */ | |
237 | ldata = arch_kexec_kernel_image_load(image); | |
238 | ||
239 | if (IS_ERR(ldata)) { | |
240 | ret = PTR_ERR(ldata); | |
241 | goto out; | |
242 | } | |
243 | ||
244 | image->image_loader_data = ldata; | |
245 | out: | |
246 | /* In case of error, free up all allocated memory in this function */ | |
247 | if (ret) | |
248 | kimage_file_post_load_cleanup(image); | |
249 | return ret; | |
250 | } | |
251 | ||
252 | static int | |
253 | kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, | |
254 | int initrd_fd, const char __user *cmdline_ptr, | |
255 | unsigned long cmdline_len, unsigned long flags) | |
256 | { | |
257 | int ret; | |
258 | struct kimage *image; | |
259 | bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; | |
260 | ||
261 | image = do_kimage_alloc_init(); | |
262 | if (!image) | |
263 | return -ENOMEM; | |
264 | ||
265 | image->file_mode = 1; | |
266 | ||
267 | if (kexec_on_panic) { | |
268 | /* Enable special crash kernel control page alloc policy. */ | |
269 | image->control_page = crashk_res.start; | |
270 | image->type = KEXEC_TYPE_CRASH; | |
271 | } | |
272 | ||
273 | ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, | |
274 | cmdline_ptr, cmdline_len, flags); | |
275 | if (ret) | |
276 | goto out_free_image; | |
277 | ||
278 | ret = sanity_check_segment_list(image); | |
279 | if (ret) | |
280 | goto out_free_post_load_bufs; | |
281 | ||
282 | ret = -ENOMEM; | |
283 | image->control_code_page = kimage_alloc_control_pages(image, | |
284 | get_order(KEXEC_CONTROL_PAGE_SIZE)); | |
285 | if (!image->control_code_page) { | |
286 | pr_err("Could not allocate control_code_buffer\n"); | |
287 | goto out_free_post_load_bufs; | |
288 | } | |
289 | ||
290 | if (!kexec_on_panic) { | |
291 | image->swap_page = kimage_alloc_control_pages(image, 0); | |
292 | if (!image->swap_page) { | |
293 | pr_err("Could not allocate swap buffer\n"); | |
294 | goto out_free_control_pages; | |
295 | } | |
296 | } | |
297 | ||
298 | *rimage = image; | |
299 | return 0; | |
300 | out_free_control_pages: | |
301 | kimage_free_page_list(&image->control_pages); | |
302 | out_free_post_load_bufs: | |
303 | kimage_file_post_load_cleanup(image); | |
304 | out_free_image: | |
305 | kfree(image); | |
306 | return ret; | |
307 | } | |
308 | ||
309 | SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, | |
310 | unsigned long, cmdline_len, const char __user *, cmdline_ptr, | |
311 | unsigned long, flags) | |
312 | { | |
313 | int ret = 0, i; | |
314 | struct kimage **dest_image, *image; | |
315 | ||
316 | /* We only trust the superuser with rebooting the system. */ | |
317 | if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) | |
318 | return -EPERM; | |
319 | ||
320 | /* Make sure we have a legal set of flags */ | |
321 | if (flags != (flags & KEXEC_FILE_FLAGS)) | |
322 | return -EINVAL; | |
323 | ||
324 | image = NULL; | |
325 | ||
326 | if (!mutex_trylock(&kexec_mutex)) | |
327 | return -EBUSY; | |
328 | ||
329 | dest_image = &kexec_image; | |
330 | if (flags & KEXEC_FILE_ON_CRASH) | |
331 | dest_image = &kexec_crash_image; | |
332 | ||
333 | if (flags & KEXEC_FILE_UNLOAD) | |
334 | goto exchange; | |
335 | ||
336 | /* | |
337 | * In case of crash, new kernel gets loaded in reserved region. It is | |
338 | * same memory where old crash kernel might be loaded. Free any | |
339 | * current crash dump kernel before we corrupt it. | |
340 | */ | |
341 | if (flags & KEXEC_FILE_ON_CRASH) | |
342 | kimage_free(xchg(&kexec_crash_image, NULL)); | |
343 | ||
344 | ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, | |
345 | cmdline_len, flags); | |
346 | if (ret) | |
347 | goto out; | |
348 | ||
349 | ret = machine_kexec_prepare(image); | |
350 | if (ret) | |
351 | goto out; | |
352 | ||
353 | ret = kexec_calculate_store_digests(image); | |
354 | if (ret) | |
355 | goto out; | |
356 | ||
357 | for (i = 0; i < image->nr_segments; i++) { | |
358 | struct kexec_segment *ksegment; | |
359 | ||
360 | ksegment = &image->segment[i]; | |
361 | pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", | |
362 | i, ksegment->buf, ksegment->bufsz, ksegment->mem, | |
363 | ksegment->memsz); | |
364 | ||
365 | ret = kimage_load_segment(image, &image->segment[i]); | |
366 | if (ret) | |
367 | goto out; | |
368 | } | |
369 | ||
370 | kimage_terminate(image); | |
371 | ||
372 | /* | |
373 | * Free up any temporary buffers allocated which are not needed | |
374 | * after image has been loaded | |
375 | */ | |
376 | kimage_file_post_load_cleanup(image); | |
377 | exchange: | |
378 | image = xchg(dest_image, image); | |
379 | out: | |
380 | mutex_unlock(&kexec_mutex); | |
381 | kimage_free(image); | |
382 | return ret; | |
383 | } | |
384 | ||
385 | static int locate_mem_hole_top_down(unsigned long start, unsigned long end, | |
386 | struct kexec_buf *kbuf) | |
387 | { | |
388 | struct kimage *image = kbuf->image; | |
389 | unsigned long temp_start, temp_end; | |
390 | ||
391 | temp_end = min(end, kbuf->buf_max); | |
392 | temp_start = temp_end - kbuf->memsz; | |
393 | ||
394 | do { | |
395 | /* align down start */ | |
396 | temp_start = temp_start & (~(kbuf->buf_align - 1)); | |
397 | ||
398 | if (temp_start < start || temp_start < kbuf->buf_min) | |
399 | return 0; | |
400 | ||
401 | temp_end = temp_start + kbuf->memsz - 1; | |
402 | ||
403 | /* | |
404 | * Make sure this does not conflict with any of existing | |
405 | * segments | |
406 | */ | |
407 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
408 | temp_start = temp_start - PAGE_SIZE; | |
409 | continue; | |
410 | } | |
411 | ||
412 | /* We found a suitable memory range */ | |
413 | break; | |
414 | } while (1); | |
415 | ||
416 | /* If we are here, we found a suitable memory range */ | |
417 | kbuf->mem = temp_start; | |
418 | ||
419 | /* Success, stop navigating through remaining System RAM ranges */ | |
420 | return 1; | |
421 | } | |
422 | ||
423 | static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, | |
424 | struct kexec_buf *kbuf) | |
425 | { | |
426 | struct kimage *image = kbuf->image; | |
427 | unsigned long temp_start, temp_end; | |
428 | ||
429 | temp_start = max(start, kbuf->buf_min); | |
430 | ||
431 | do { | |
432 | temp_start = ALIGN(temp_start, kbuf->buf_align); | |
433 | temp_end = temp_start + kbuf->memsz - 1; | |
434 | ||
435 | if (temp_end > end || temp_end > kbuf->buf_max) | |
436 | return 0; | |
437 | /* | |
438 | * Make sure this does not conflict with any of existing | |
439 | * segments | |
440 | */ | |
441 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
442 | temp_start = temp_start + PAGE_SIZE; | |
443 | continue; | |
444 | } | |
445 | ||
446 | /* We found a suitable memory range */ | |
447 | break; | |
448 | } while (1); | |
449 | ||
450 | /* If we are here, we found a suitable memory range */ | |
451 | kbuf->mem = temp_start; | |
452 | ||
453 | /* Success, stop navigating through remaining System RAM ranges */ | |
454 | return 1; | |
455 | } | |
456 | ||
457 | static int locate_mem_hole_callback(u64 start, u64 end, void *arg) | |
458 | { | |
459 | struct kexec_buf *kbuf = (struct kexec_buf *)arg; | |
460 | unsigned long sz = end - start + 1; | |
461 | ||
462 | /* Returning 0 will take to next memory range */ | |
463 | if (sz < kbuf->memsz) | |
464 | return 0; | |
465 | ||
466 | if (end < kbuf->buf_min || start > kbuf->buf_max) | |
467 | return 0; | |
468 | ||
469 | /* | |
470 | * Allocate memory top down with-in ram range. Otherwise bottom up | |
471 | * allocation. | |
472 | */ | |
473 | if (kbuf->top_down) | |
474 | return locate_mem_hole_top_down(start, end, kbuf); | |
475 | return locate_mem_hole_bottom_up(start, end, kbuf); | |
476 | } | |
477 | ||
478 | /* | |
479 | * Helper function for placing a buffer in a kexec segment. This assumes | |
480 | * that kexec_mutex is held. | |
481 | */ | |
482 | int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz, | |
483 | unsigned long memsz, unsigned long buf_align, | |
484 | unsigned long buf_min, unsigned long buf_max, | |
485 | bool top_down, unsigned long *load_addr) | |
486 | { | |
487 | ||
488 | struct kexec_segment *ksegment; | |
489 | struct kexec_buf buf, *kbuf; | |
490 | int ret; | |
491 | ||
492 | /* Currently adding segment this way is allowed only in file mode */ | |
493 | if (!image->file_mode) | |
494 | return -EINVAL; | |
495 | ||
496 | if (image->nr_segments >= KEXEC_SEGMENT_MAX) | |
497 | return -EINVAL; | |
498 | ||
499 | /* | |
500 | * Make sure we are not trying to add buffer after allocating | |
501 | * control pages. All segments need to be placed first before | |
502 | * any control pages are allocated. As control page allocation | |
503 | * logic goes through list of segments to make sure there are | |
504 | * no destination overlaps. | |
505 | */ | |
506 | if (!list_empty(&image->control_pages)) { | |
507 | WARN_ON(1); | |
508 | return -EINVAL; | |
509 | } | |
510 | ||
511 | memset(&buf, 0, sizeof(struct kexec_buf)); | |
512 | kbuf = &buf; | |
513 | kbuf->image = image; | |
514 | kbuf->buffer = buffer; | |
515 | kbuf->bufsz = bufsz; | |
516 | ||
517 | kbuf->memsz = ALIGN(memsz, PAGE_SIZE); | |
518 | kbuf->buf_align = max(buf_align, PAGE_SIZE); | |
519 | kbuf->buf_min = buf_min; | |
520 | kbuf->buf_max = buf_max; | |
521 | kbuf->top_down = top_down; | |
522 | ||
523 | /* Walk the RAM ranges and allocate a suitable range for the buffer */ | |
524 | if (image->type == KEXEC_TYPE_CRASH) | |
525 | ret = walk_iomem_res("Crash kernel", | |
526 | IORESOURCE_MEM | IORESOURCE_BUSY, | |
527 | crashk_res.start, crashk_res.end, kbuf, | |
528 | locate_mem_hole_callback); | |
529 | else | |
530 | ret = walk_system_ram_res(0, -1, kbuf, | |
531 | locate_mem_hole_callback); | |
532 | if (ret != 1) { | |
533 | /* A suitable memory range could not be found for buffer */ | |
534 | return -EADDRNOTAVAIL; | |
535 | } | |
536 | ||
537 | /* Found a suitable memory range */ | |
538 | ksegment = &image->segment[image->nr_segments]; | |
539 | ksegment->kbuf = kbuf->buffer; | |
540 | ksegment->bufsz = kbuf->bufsz; | |
541 | ksegment->mem = kbuf->mem; | |
542 | ksegment->memsz = kbuf->memsz; | |
543 | image->nr_segments++; | |
544 | *load_addr = ksegment->mem; | |
545 | return 0; | |
546 | } | |
547 | ||
548 | /* Calculate and store the digest of segments */ | |
549 | static int kexec_calculate_store_digests(struct kimage *image) | |
550 | { | |
551 | struct crypto_shash *tfm; | |
552 | struct shash_desc *desc; | |
553 | int ret = 0, i, j, zero_buf_sz, sha_region_sz; | |
554 | size_t desc_size, nullsz; | |
555 | char *digest; | |
556 | void *zero_buf; | |
557 | struct kexec_sha_region *sha_regions; | |
558 | struct purgatory_info *pi = &image->purgatory_info; | |
559 | ||
560 | zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); | |
561 | zero_buf_sz = PAGE_SIZE; | |
562 | ||
563 | tfm = crypto_alloc_shash("sha256", 0, 0); | |
564 | if (IS_ERR(tfm)) { | |
565 | ret = PTR_ERR(tfm); | |
566 | goto out; | |
567 | } | |
568 | ||
569 | desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); | |
570 | desc = kzalloc(desc_size, GFP_KERNEL); | |
571 | if (!desc) { | |
572 | ret = -ENOMEM; | |
573 | goto out_free_tfm; | |
574 | } | |
575 | ||
576 | sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); | |
577 | sha_regions = vzalloc(sha_region_sz); | |
578 | if (!sha_regions) | |
579 | goto out_free_desc; | |
580 | ||
581 | desc->tfm = tfm; | |
582 | desc->flags = 0; | |
583 | ||
584 | ret = crypto_shash_init(desc); | |
585 | if (ret < 0) | |
586 | goto out_free_sha_regions; | |
587 | ||
588 | digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); | |
589 | if (!digest) { | |
590 | ret = -ENOMEM; | |
591 | goto out_free_sha_regions; | |
592 | } | |
593 | ||
594 | for (j = i = 0; i < image->nr_segments; i++) { | |
595 | struct kexec_segment *ksegment; | |
596 | ||
597 | ksegment = &image->segment[i]; | |
598 | /* | |
599 | * Skip purgatory as it will be modified once we put digest | |
600 | * info in purgatory. | |
601 | */ | |
602 | if (ksegment->kbuf == pi->purgatory_buf) | |
603 | continue; | |
604 | ||
605 | ret = crypto_shash_update(desc, ksegment->kbuf, | |
606 | ksegment->bufsz); | |
607 | if (ret) | |
608 | break; | |
609 | ||
610 | /* | |
611 | * Assume rest of the buffer is filled with zero and | |
612 | * update digest accordingly. | |
613 | */ | |
614 | nullsz = ksegment->memsz - ksegment->bufsz; | |
615 | while (nullsz) { | |
616 | unsigned long bytes = nullsz; | |
617 | ||
618 | if (bytes > zero_buf_sz) | |
619 | bytes = zero_buf_sz; | |
620 | ret = crypto_shash_update(desc, zero_buf, bytes); | |
621 | if (ret) | |
622 | break; | |
623 | nullsz -= bytes; | |
624 | } | |
625 | ||
626 | if (ret) | |
627 | break; | |
628 | ||
629 | sha_regions[j].start = ksegment->mem; | |
630 | sha_regions[j].len = ksegment->memsz; | |
631 | j++; | |
632 | } | |
633 | ||
634 | if (!ret) { | |
635 | ret = crypto_shash_final(desc, digest); | |
636 | if (ret) | |
637 | goto out_free_digest; | |
638 | ret = kexec_purgatory_get_set_symbol(image, "sha_regions", | |
639 | sha_regions, sha_region_sz, 0); | |
640 | if (ret) | |
641 | goto out_free_digest; | |
642 | ||
643 | ret = kexec_purgatory_get_set_symbol(image, "sha256_digest", | |
644 | digest, SHA256_DIGEST_SIZE, 0); | |
645 | if (ret) | |
646 | goto out_free_digest; | |
647 | } | |
648 | ||
649 | out_free_digest: | |
650 | kfree(digest); | |
651 | out_free_sha_regions: | |
652 | vfree(sha_regions); | |
653 | out_free_desc: | |
654 | kfree(desc); | |
655 | out_free_tfm: | |
656 | kfree(tfm); | |
657 | out: | |
658 | return ret; | |
659 | } | |
660 | ||
661 | /* Actually load purgatory. Lot of code taken from kexec-tools */ | |
662 | static int __kexec_load_purgatory(struct kimage *image, unsigned long min, | |
663 | unsigned long max, int top_down) | |
664 | { | |
665 | struct purgatory_info *pi = &image->purgatory_info; | |
666 | unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad; | |
667 | unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset; | |
668 | unsigned char *buf_addr, *src; | |
669 | int i, ret = 0, entry_sidx = -1; | |
670 | const Elf_Shdr *sechdrs_c; | |
671 | Elf_Shdr *sechdrs = NULL; | |
672 | void *purgatory_buf = NULL; | |
673 | ||
674 | /* | |
675 | * sechdrs_c points to section headers in purgatory and are read | |
676 | * only. No modifications allowed. | |
677 | */ | |
678 | sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff; | |
679 | ||
680 | /* | |
681 | * We can not modify sechdrs_c[] and its fields. It is read only. | |
682 | * Copy it over to a local copy where one can store some temporary | |
683 | * data and free it at the end. We need to modify ->sh_addr and | |
684 | * ->sh_offset fields to keep track of permanent and temporary | |
685 | * locations of sections. | |
686 | */ | |
687 | sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
688 | if (!sechdrs) | |
689 | return -ENOMEM; | |
690 | ||
691 | memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
692 | ||
693 | /* | |
694 | * We seem to have multiple copies of sections. First copy is which | |
695 | * is embedded in kernel in read only section. Some of these sections | |
696 | * will be copied to a temporary buffer and relocated. And these | |
697 | * sections will finally be copied to their final destination at | |
698 | * segment load time. | |
699 | * | |
700 | * Use ->sh_offset to reflect section address in memory. It will | |
701 | * point to original read only copy if section is not allocatable. | |
702 | * Otherwise it will point to temporary copy which will be relocated. | |
703 | * | |
704 | * Use ->sh_addr to contain final address of the section where it | |
705 | * will go during execution time. | |
706 | */ | |
707 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
708 | if (sechdrs[i].sh_type == SHT_NOBITS) | |
709 | continue; | |
710 | ||
711 | sechdrs[i].sh_offset = (unsigned long)pi->ehdr + | |
712 | sechdrs[i].sh_offset; | |
713 | } | |
714 | ||
715 | /* | |
716 | * Identify entry point section and make entry relative to section | |
717 | * start. | |
718 | */ | |
719 | entry = pi->ehdr->e_entry; | |
720 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
721 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
722 | continue; | |
723 | ||
724 | if (!(sechdrs[i].sh_flags & SHF_EXECINSTR)) | |
725 | continue; | |
726 | ||
727 | /* Make entry section relative */ | |
728 | if (sechdrs[i].sh_addr <= pi->ehdr->e_entry && | |
729 | ((sechdrs[i].sh_addr + sechdrs[i].sh_size) > | |
730 | pi->ehdr->e_entry)) { | |
731 | entry_sidx = i; | |
732 | entry -= sechdrs[i].sh_addr; | |
733 | break; | |
734 | } | |
735 | } | |
736 | ||
737 | /* Determine how much memory is needed to load relocatable object. */ | |
738 | buf_align = 1; | |
739 | bss_align = 1; | |
740 | buf_sz = 0; | |
741 | bss_sz = 0; | |
742 | ||
743 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
744 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
745 | continue; | |
746 | ||
747 | align = sechdrs[i].sh_addralign; | |
748 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
749 | if (buf_align < align) | |
750 | buf_align = align; | |
751 | buf_sz = ALIGN(buf_sz, align); | |
752 | buf_sz += sechdrs[i].sh_size; | |
753 | } else { | |
754 | /* bss section */ | |
755 | if (bss_align < align) | |
756 | bss_align = align; | |
757 | bss_sz = ALIGN(bss_sz, align); | |
758 | bss_sz += sechdrs[i].sh_size; | |
759 | } | |
760 | } | |
761 | ||
762 | /* Determine the bss padding required to align bss properly */ | |
763 | bss_pad = 0; | |
764 | if (buf_sz & (bss_align - 1)) | |
765 | bss_pad = bss_align - (buf_sz & (bss_align - 1)); | |
766 | ||
767 | memsz = buf_sz + bss_pad + bss_sz; | |
768 | ||
769 | /* Allocate buffer for purgatory */ | |
770 | purgatory_buf = vzalloc(buf_sz); | |
771 | if (!purgatory_buf) { | |
772 | ret = -ENOMEM; | |
773 | goto out; | |
774 | } | |
775 | ||
776 | if (buf_align < bss_align) | |
777 | buf_align = bss_align; | |
778 | ||
779 | /* Add buffer to segment list */ | |
780 | ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz, | |
781 | buf_align, min, max, top_down, | |
782 | &pi->purgatory_load_addr); | |
783 | if (ret) | |
784 | goto out; | |
785 | ||
786 | /* Load SHF_ALLOC sections */ | |
787 | buf_addr = purgatory_buf; | |
788 | load_addr = curr_load_addr = pi->purgatory_load_addr; | |
789 | bss_addr = load_addr + buf_sz + bss_pad; | |
790 | ||
791 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
792 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
793 | continue; | |
794 | ||
795 | align = sechdrs[i].sh_addralign; | |
796 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
797 | curr_load_addr = ALIGN(curr_load_addr, align); | |
798 | offset = curr_load_addr - load_addr; | |
799 | /* We already modifed ->sh_offset to keep src addr */ | |
800 | src = (char *) sechdrs[i].sh_offset; | |
801 | memcpy(buf_addr + offset, src, sechdrs[i].sh_size); | |
802 | ||
803 | /* Store load address and source address of section */ | |
804 | sechdrs[i].sh_addr = curr_load_addr; | |
805 | ||
806 | /* | |
807 | * This section got copied to temporary buffer. Update | |
808 | * ->sh_offset accordingly. | |
809 | */ | |
810 | sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset); | |
811 | ||
812 | /* Advance to the next address */ | |
813 | curr_load_addr += sechdrs[i].sh_size; | |
814 | } else { | |
815 | bss_addr = ALIGN(bss_addr, align); | |
816 | sechdrs[i].sh_addr = bss_addr; | |
817 | bss_addr += sechdrs[i].sh_size; | |
818 | } | |
819 | } | |
820 | ||
821 | /* Update entry point based on load address of text section */ | |
822 | if (entry_sidx >= 0) | |
823 | entry += sechdrs[entry_sidx].sh_addr; | |
824 | ||
825 | /* Make kernel jump to purgatory after shutdown */ | |
826 | image->start = entry; | |
827 | ||
828 | /* Used later to get/set symbol values */ | |
829 | pi->sechdrs = sechdrs; | |
830 | ||
831 | /* | |
832 | * Used later to identify which section is purgatory and skip it | |
833 | * from checksumming. | |
834 | */ | |
835 | pi->purgatory_buf = purgatory_buf; | |
836 | return ret; | |
837 | out: | |
838 | vfree(sechdrs); | |
839 | vfree(purgatory_buf); | |
840 | return ret; | |
841 | } | |
842 | ||
843 | static int kexec_apply_relocations(struct kimage *image) | |
844 | { | |
845 | int i, ret; | |
846 | struct purgatory_info *pi = &image->purgatory_info; | |
847 | Elf_Shdr *sechdrs = pi->sechdrs; | |
848 | ||
849 | /* Apply relocations */ | |
850 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
851 | Elf_Shdr *section, *symtab; | |
852 | ||
853 | if (sechdrs[i].sh_type != SHT_RELA && | |
854 | sechdrs[i].sh_type != SHT_REL) | |
855 | continue; | |
856 | ||
857 | /* | |
858 | * For section of type SHT_RELA/SHT_REL, | |
859 | * ->sh_link contains section header index of associated | |
860 | * symbol table. And ->sh_info contains section header | |
861 | * index of section to which relocations apply. | |
862 | */ | |
863 | if (sechdrs[i].sh_info >= pi->ehdr->e_shnum || | |
864 | sechdrs[i].sh_link >= pi->ehdr->e_shnum) | |
865 | return -ENOEXEC; | |
866 | ||
867 | section = &sechdrs[sechdrs[i].sh_info]; | |
868 | symtab = &sechdrs[sechdrs[i].sh_link]; | |
869 | ||
870 | if (!(section->sh_flags & SHF_ALLOC)) | |
871 | continue; | |
872 | ||
873 | /* | |
874 | * symtab->sh_link contain section header index of associated | |
875 | * string table. | |
876 | */ | |
877 | if (symtab->sh_link >= pi->ehdr->e_shnum) | |
878 | /* Invalid section number? */ | |
879 | continue; | |
880 | ||
881 | /* | |
882 | * Respective architecture needs to provide support for applying | |
883 | * relocations of type SHT_RELA/SHT_REL. | |
884 | */ | |
885 | if (sechdrs[i].sh_type == SHT_RELA) | |
886 | ret = arch_kexec_apply_relocations_add(pi->ehdr, | |
887 | sechdrs, i); | |
888 | else if (sechdrs[i].sh_type == SHT_REL) | |
889 | ret = arch_kexec_apply_relocations(pi->ehdr, | |
890 | sechdrs, i); | |
891 | if (ret) | |
892 | return ret; | |
893 | } | |
894 | ||
895 | return 0; | |
896 | } | |
897 | ||
898 | /* Load relocatable purgatory object and relocate it appropriately */ | |
899 | int kexec_load_purgatory(struct kimage *image, unsigned long min, | |
900 | unsigned long max, int top_down, | |
901 | unsigned long *load_addr) | |
902 | { | |
903 | struct purgatory_info *pi = &image->purgatory_info; | |
904 | int ret; | |
905 | ||
906 | if (kexec_purgatory_size <= 0) | |
907 | return -EINVAL; | |
908 | ||
909 | if (kexec_purgatory_size < sizeof(Elf_Ehdr)) | |
910 | return -ENOEXEC; | |
911 | ||
912 | pi->ehdr = (Elf_Ehdr *)kexec_purgatory; | |
913 | ||
914 | if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0 | |
915 | || pi->ehdr->e_type != ET_REL | |
916 | || !elf_check_arch(pi->ehdr) | |
917 | || pi->ehdr->e_shentsize != sizeof(Elf_Shdr)) | |
918 | return -ENOEXEC; | |
919 | ||
920 | if (pi->ehdr->e_shoff >= kexec_purgatory_size | |
921 | || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) > | |
922 | kexec_purgatory_size - pi->ehdr->e_shoff)) | |
923 | return -ENOEXEC; | |
924 | ||
925 | ret = __kexec_load_purgatory(image, min, max, top_down); | |
926 | if (ret) | |
927 | return ret; | |
928 | ||
929 | ret = kexec_apply_relocations(image); | |
930 | if (ret) | |
931 | goto out; | |
932 | ||
933 | *load_addr = pi->purgatory_load_addr; | |
934 | return 0; | |
935 | out: | |
936 | vfree(pi->sechdrs); | |
937 | vfree(pi->purgatory_buf); | |
938 | return ret; | |
939 | } | |
940 | ||
941 | static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, | |
942 | const char *name) | |
943 | { | |
944 | Elf_Sym *syms; | |
945 | Elf_Shdr *sechdrs; | |
946 | Elf_Ehdr *ehdr; | |
947 | int i, k; | |
948 | const char *strtab; | |
949 | ||
950 | if (!pi->sechdrs || !pi->ehdr) | |
951 | return NULL; | |
952 | ||
953 | sechdrs = pi->sechdrs; | |
954 | ehdr = pi->ehdr; | |
955 | ||
956 | for (i = 0; i < ehdr->e_shnum; i++) { | |
957 | if (sechdrs[i].sh_type != SHT_SYMTAB) | |
958 | continue; | |
959 | ||
960 | if (sechdrs[i].sh_link >= ehdr->e_shnum) | |
961 | /* Invalid strtab section number */ | |
962 | continue; | |
963 | strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset; | |
964 | syms = (Elf_Sym *)sechdrs[i].sh_offset; | |
965 | ||
966 | /* Go through symbols for a match */ | |
967 | for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { | |
968 | if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) | |
969 | continue; | |
970 | ||
971 | if (strcmp(strtab + syms[k].st_name, name) != 0) | |
972 | continue; | |
973 | ||
974 | if (syms[k].st_shndx == SHN_UNDEF || | |
975 | syms[k].st_shndx >= ehdr->e_shnum) { | |
976 | pr_debug("Symbol: %s has bad section index %d.\n", | |
977 | name, syms[k].st_shndx); | |
978 | return NULL; | |
979 | } | |
980 | ||
981 | /* Found the symbol we are looking for */ | |
982 | return &syms[k]; | |
983 | } | |
984 | } | |
985 | ||
986 | return NULL; | |
987 | } | |
988 | ||
989 | void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) | |
990 | { | |
991 | struct purgatory_info *pi = &image->purgatory_info; | |
992 | Elf_Sym *sym; | |
993 | Elf_Shdr *sechdr; | |
994 | ||
995 | sym = kexec_purgatory_find_symbol(pi, name); | |
996 | if (!sym) | |
997 | return ERR_PTR(-EINVAL); | |
998 | ||
999 | sechdr = &pi->sechdrs[sym->st_shndx]; | |
1000 | ||
1001 | /* | |
1002 | * Returns the address where symbol will finally be loaded after | |
1003 | * kexec_load_segment() | |
1004 | */ | |
1005 | return (void *)(sechdr->sh_addr + sym->st_value); | |
1006 | } | |
1007 | ||
1008 | /* | |
1009 | * Get or set value of a symbol. If "get_value" is true, symbol value is | |
1010 | * returned in buf otherwise symbol value is set based on value in buf. | |
1011 | */ | |
1012 | int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, | |
1013 | void *buf, unsigned int size, bool get_value) | |
1014 | { | |
1015 | Elf_Sym *sym; | |
1016 | Elf_Shdr *sechdrs; | |
1017 | struct purgatory_info *pi = &image->purgatory_info; | |
1018 | char *sym_buf; | |
1019 | ||
1020 | sym = kexec_purgatory_find_symbol(pi, name); | |
1021 | if (!sym) | |
1022 | return -EINVAL; | |
1023 | ||
1024 | if (sym->st_size != size) { | |
1025 | pr_err("symbol %s size mismatch: expected %lu actual %u\n", | |
1026 | name, (unsigned long)sym->st_size, size); | |
1027 | return -EINVAL; | |
1028 | } | |
1029 | ||
1030 | sechdrs = pi->sechdrs; | |
1031 | ||
1032 | if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) { | |
1033 | pr_err("symbol %s is in a bss section. Cannot %s\n", name, | |
1034 | get_value ? "get" : "set"); | |
1035 | return -EINVAL; | |
1036 | } | |
1037 | ||
1038 | sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset + | |
1039 | sym->st_value; | |
1040 | ||
1041 | if (get_value) | |
1042 | memcpy((void *)buf, sym_buf, size); | |
1043 | else | |
1044 | memcpy((void *)sym_buf, buf, size); | |
1045 | ||
1046 | return 0; | |
1047 | } |