Commit | Line | Data |
---|---|---|
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> | |
b804defe | 21 | #include <linux/fs.h> |
7b8589cc | 22 | #include <linux/ima.h> |
a43cac0d DY |
23 | #include <crypto/hash.h> |
24 | #include <crypto/sha.h> | |
25 | #include <linux/syscalls.h> | |
26 | #include <linux/vmalloc.h> | |
27 | #include "kexec_internal.h" | |
28 | ||
29 | /* | |
30 | * Declare these symbols weak so that if architecture provides a purgatory, | |
31 | * these will be overridden. | |
32 | */ | |
33 | char __weak kexec_purgatory[0]; | |
34 | size_t __weak kexec_purgatory_size = 0; | |
35 | ||
36 | static int kexec_calculate_store_digests(struct kimage *image); | |
37 | ||
a43cac0d DY |
38 | /* Architectures can provide this probe function */ |
39 | int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, | |
40 | unsigned long buf_len) | |
41 | { | |
42 | return -ENOEXEC; | |
43 | } | |
44 | ||
45 | void * __weak arch_kexec_kernel_image_load(struct kimage *image) | |
46 | { | |
47 | return ERR_PTR(-ENOEXEC); | |
48 | } | |
49 | ||
50 | int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) | |
51 | { | |
52 | return -EINVAL; | |
53 | } | |
54 | ||
978e30c9 | 55 | #ifdef CONFIG_KEXEC_VERIFY_SIG |
a43cac0d DY |
56 | int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, |
57 | unsigned long buf_len) | |
58 | { | |
59 | return -EKEYREJECTED; | |
60 | } | |
978e30c9 | 61 | #endif |
a43cac0d DY |
62 | |
63 | /* Apply relocations of type RELA */ | |
64 | int __weak | |
65 | arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
66 | unsigned int relsec) | |
67 | { | |
68 | pr_err("RELA relocation unsupported.\n"); | |
69 | return -ENOEXEC; | |
70 | } | |
71 | ||
72 | /* Apply relocations of type REL */ | |
73 | int __weak | |
74 | arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
75 | unsigned int relsec) | |
76 | { | |
77 | pr_err("REL relocation unsupported.\n"); | |
78 | return -ENOEXEC; | |
79 | } | |
80 | ||
81 | /* | |
82 | * Free up memory used by kernel, initrd, and command line. This is temporary | |
83 | * memory allocation which is not needed any more after these buffers have | |
84 | * been loaded into separate segments and have been copied elsewhere. | |
85 | */ | |
86 | void kimage_file_post_load_cleanup(struct kimage *image) | |
87 | { | |
88 | struct purgatory_info *pi = &image->purgatory_info; | |
89 | ||
90 | vfree(image->kernel_buf); | |
91 | image->kernel_buf = NULL; | |
92 | ||
93 | vfree(image->initrd_buf); | |
94 | image->initrd_buf = NULL; | |
95 | ||
96 | kfree(image->cmdline_buf); | |
97 | image->cmdline_buf = NULL; | |
98 | ||
99 | vfree(pi->purgatory_buf); | |
100 | pi->purgatory_buf = NULL; | |
101 | ||
102 | vfree(pi->sechdrs); | |
103 | pi->sechdrs = NULL; | |
104 | ||
105 | /* See if architecture has anything to cleanup post load */ | |
106 | arch_kimage_file_post_load_cleanup(image); | |
107 | ||
108 | /* | |
109 | * Above call should have called into bootloader to free up | |
110 | * any data stored in kimage->image_loader_data. It should | |
111 | * be ok now to free it up. | |
112 | */ | |
113 | kfree(image->image_loader_data); | |
114 | image->image_loader_data = NULL; | |
115 | } | |
116 | ||
117 | /* | |
118 | * In file mode list of segments is prepared by kernel. Copy relevant | |
119 | * data from user space, do error checking, prepare segment list | |
120 | */ | |
121 | static int | |
122 | kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, | |
123 | const char __user *cmdline_ptr, | |
124 | unsigned long cmdline_len, unsigned flags) | |
125 | { | |
126 | int ret = 0; | |
127 | void *ldata; | |
b804defe | 128 | loff_t size; |
a43cac0d | 129 | |
b804defe MZ |
130 | ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, |
131 | &size, INT_MAX, READING_KEXEC_IMAGE); | |
a43cac0d DY |
132 | if (ret) |
133 | return ret; | |
b804defe | 134 | image->kernel_buf_len = size; |
a43cac0d | 135 | |
7b8589cc MZ |
136 | /* IMA needs to pass the measurement list to the next kernel. */ |
137 | ima_add_kexec_buffer(image); | |
138 | ||
a43cac0d DY |
139 | /* Call arch image probe handlers */ |
140 | ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, | |
141 | image->kernel_buf_len); | |
a43cac0d DY |
142 | if (ret) |
143 | goto out; | |
144 | ||
145 | #ifdef CONFIG_KEXEC_VERIFY_SIG | |
146 | ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, | |
147 | image->kernel_buf_len); | |
148 | if (ret) { | |
149 | pr_debug("kernel signature verification failed.\n"); | |
150 | goto out; | |
151 | } | |
152 | pr_debug("kernel signature verification successful.\n"); | |
153 | #endif | |
154 | /* It is possible that there no initramfs is being loaded */ | |
155 | if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { | |
b804defe MZ |
156 | ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, |
157 | &size, INT_MAX, | |
158 | READING_KEXEC_INITRAMFS); | |
a43cac0d DY |
159 | if (ret) |
160 | goto out; | |
b804defe | 161 | image->initrd_buf_len = size; |
a43cac0d DY |
162 | } |
163 | ||
164 | if (cmdline_len) { | |
165 | image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL); | |
166 | if (!image->cmdline_buf) { | |
167 | ret = -ENOMEM; | |
168 | goto out; | |
169 | } | |
170 | ||
171 | ret = copy_from_user(image->cmdline_buf, cmdline_ptr, | |
172 | cmdline_len); | |
173 | if (ret) { | |
174 | ret = -EFAULT; | |
175 | goto out; | |
176 | } | |
177 | ||
178 | image->cmdline_buf_len = cmdline_len; | |
179 | ||
180 | /* command line should be a string with last byte null */ | |
181 | if (image->cmdline_buf[cmdline_len - 1] != '\0') { | |
182 | ret = -EINVAL; | |
183 | goto out; | |
184 | } | |
185 | } | |
186 | ||
187 | /* Call arch image load handlers */ | |
188 | ldata = arch_kexec_kernel_image_load(image); | |
189 | ||
190 | if (IS_ERR(ldata)) { | |
191 | ret = PTR_ERR(ldata); | |
192 | goto out; | |
193 | } | |
194 | ||
195 | image->image_loader_data = ldata; | |
196 | out: | |
197 | /* In case of error, free up all allocated memory in this function */ | |
198 | if (ret) | |
199 | kimage_file_post_load_cleanup(image); | |
200 | return ret; | |
201 | } | |
202 | ||
203 | static int | |
204 | kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, | |
205 | int initrd_fd, const char __user *cmdline_ptr, | |
206 | unsigned long cmdline_len, unsigned long flags) | |
207 | { | |
208 | int ret; | |
209 | struct kimage *image; | |
210 | bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; | |
211 | ||
212 | image = do_kimage_alloc_init(); | |
213 | if (!image) | |
214 | return -ENOMEM; | |
215 | ||
216 | image->file_mode = 1; | |
217 | ||
218 | if (kexec_on_panic) { | |
219 | /* Enable special crash kernel control page alloc policy. */ | |
220 | image->control_page = crashk_res.start; | |
221 | image->type = KEXEC_TYPE_CRASH; | |
222 | } | |
223 | ||
224 | ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, | |
225 | cmdline_ptr, cmdline_len, flags); | |
226 | if (ret) | |
227 | goto out_free_image; | |
228 | ||
229 | ret = sanity_check_segment_list(image); | |
230 | if (ret) | |
231 | goto out_free_post_load_bufs; | |
232 | ||
233 | ret = -ENOMEM; | |
234 | image->control_code_page = kimage_alloc_control_pages(image, | |
235 | get_order(KEXEC_CONTROL_PAGE_SIZE)); | |
236 | if (!image->control_code_page) { | |
237 | pr_err("Could not allocate control_code_buffer\n"); | |
238 | goto out_free_post_load_bufs; | |
239 | } | |
240 | ||
241 | if (!kexec_on_panic) { | |
242 | image->swap_page = kimage_alloc_control_pages(image, 0); | |
243 | if (!image->swap_page) { | |
244 | pr_err("Could not allocate swap buffer\n"); | |
245 | goto out_free_control_pages; | |
246 | } | |
247 | } | |
248 | ||
249 | *rimage = image; | |
250 | return 0; | |
251 | out_free_control_pages: | |
252 | kimage_free_page_list(&image->control_pages); | |
253 | out_free_post_load_bufs: | |
254 | kimage_file_post_load_cleanup(image); | |
255 | out_free_image: | |
256 | kfree(image); | |
257 | return ret; | |
258 | } | |
259 | ||
260 | SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, | |
261 | unsigned long, cmdline_len, const char __user *, cmdline_ptr, | |
262 | unsigned long, flags) | |
263 | { | |
264 | int ret = 0, i; | |
265 | struct kimage **dest_image, *image; | |
266 | ||
267 | /* We only trust the superuser with rebooting the system. */ | |
268 | if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) | |
269 | return -EPERM; | |
270 | ||
271 | /* Make sure we have a legal set of flags */ | |
272 | if (flags != (flags & KEXEC_FILE_FLAGS)) | |
273 | return -EINVAL; | |
274 | ||
275 | image = NULL; | |
276 | ||
277 | if (!mutex_trylock(&kexec_mutex)) | |
278 | return -EBUSY; | |
279 | ||
280 | dest_image = &kexec_image; | |
9b492cf5 | 281 | if (flags & KEXEC_FILE_ON_CRASH) { |
a43cac0d | 282 | dest_image = &kexec_crash_image; |
9b492cf5 XP |
283 | if (kexec_crash_image) |
284 | arch_kexec_unprotect_crashkres(); | |
285 | } | |
a43cac0d DY |
286 | |
287 | if (flags & KEXEC_FILE_UNLOAD) | |
288 | goto exchange; | |
289 | ||
290 | /* | |
291 | * In case of crash, new kernel gets loaded in reserved region. It is | |
292 | * same memory where old crash kernel might be loaded. Free any | |
293 | * current crash dump kernel before we corrupt it. | |
294 | */ | |
295 | if (flags & KEXEC_FILE_ON_CRASH) | |
296 | kimage_free(xchg(&kexec_crash_image, NULL)); | |
297 | ||
298 | ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, | |
299 | cmdline_len, flags); | |
300 | if (ret) | |
301 | goto out; | |
302 | ||
303 | ret = machine_kexec_prepare(image); | |
304 | if (ret) | |
305 | goto out; | |
306 | ||
307 | ret = kexec_calculate_store_digests(image); | |
308 | if (ret) | |
309 | goto out; | |
310 | ||
311 | for (i = 0; i < image->nr_segments; i++) { | |
312 | struct kexec_segment *ksegment; | |
313 | ||
314 | ksegment = &image->segment[i]; | |
315 | pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", | |
316 | i, ksegment->buf, ksegment->bufsz, ksegment->mem, | |
317 | ksegment->memsz); | |
318 | ||
319 | ret = kimage_load_segment(image, &image->segment[i]); | |
320 | if (ret) | |
321 | goto out; | |
322 | } | |
323 | ||
324 | kimage_terminate(image); | |
325 | ||
326 | /* | |
327 | * Free up any temporary buffers allocated which are not needed | |
328 | * after image has been loaded | |
329 | */ | |
330 | kimage_file_post_load_cleanup(image); | |
331 | exchange: | |
332 | image = xchg(dest_image, image); | |
333 | out: | |
9b492cf5 XP |
334 | if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) |
335 | arch_kexec_protect_crashkres(); | |
336 | ||
a43cac0d DY |
337 | mutex_unlock(&kexec_mutex); |
338 | kimage_free(image); | |
339 | return ret; | |
340 | } | |
341 | ||
342 | static int locate_mem_hole_top_down(unsigned long start, unsigned long end, | |
343 | struct kexec_buf *kbuf) | |
344 | { | |
345 | struct kimage *image = kbuf->image; | |
346 | unsigned long temp_start, temp_end; | |
347 | ||
348 | temp_end = min(end, kbuf->buf_max); | |
349 | temp_start = temp_end - kbuf->memsz; | |
350 | ||
351 | do { | |
352 | /* align down start */ | |
353 | temp_start = temp_start & (~(kbuf->buf_align - 1)); | |
354 | ||
355 | if (temp_start < start || temp_start < kbuf->buf_min) | |
356 | return 0; | |
357 | ||
358 | temp_end = temp_start + kbuf->memsz - 1; | |
359 | ||
360 | /* | |
361 | * Make sure this does not conflict with any of existing | |
362 | * segments | |
363 | */ | |
364 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
365 | temp_start = temp_start - PAGE_SIZE; | |
366 | continue; | |
367 | } | |
368 | ||
369 | /* We found a suitable memory range */ | |
370 | break; | |
371 | } while (1); | |
372 | ||
373 | /* If we are here, we found a suitable memory range */ | |
374 | kbuf->mem = temp_start; | |
375 | ||
376 | /* Success, stop navigating through remaining System RAM ranges */ | |
377 | return 1; | |
378 | } | |
379 | ||
380 | static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, | |
381 | struct kexec_buf *kbuf) | |
382 | { | |
383 | struct kimage *image = kbuf->image; | |
384 | unsigned long temp_start, temp_end; | |
385 | ||
386 | temp_start = max(start, kbuf->buf_min); | |
387 | ||
388 | do { | |
389 | temp_start = ALIGN(temp_start, kbuf->buf_align); | |
390 | temp_end = temp_start + kbuf->memsz - 1; | |
391 | ||
392 | if (temp_end > end || temp_end > kbuf->buf_max) | |
393 | return 0; | |
394 | /* | |
395 | * Make sure this does not conflict with any of existing | |
396 | * segments | |
397 | */ | |
398 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
399 | temp_start = temp_start + PAGE_SIZE; | |
400 | continue; | |
401 | } | |
402 | ||
403 | /* We found a suitable memory range */ | |
404 | break; | |
405 | } while (1); | |
406 | ||
407 | /* If we are here, we found a suitable memory range */ | |
408 | kbuf->mem = temp_start; | |
409 | ||
410 | /* Success, stop navigating through remaining System RAM ranges */ | |
411 | return 1; | |
412 | } | |
413 | ||
414 | static int locate_mem_hole_callback(u64 start, u64 end, void *arg) | |
415 | { | |
416 | struct kexec_buf *kbuf = (struct kexec_buf *)arg; | |
417 | unsigned long sz = end - start + 1; | |
418 | ||
419 | /* Returning 0 will take to next memory range */ | |
420 | if (sz < kbuf->memsz) | |
421 | return 0; | |
422 | ||
423 | if (end < kbuf->buf_min || start > kbuf->buf_max) | |
424 | return 0; | |
425 | ||
426 | /* | |
427 | * Allocate memory top down with-in ram range. Otherwise bottom up | |
428 | * allocation. | |
429 | */ | |
430 | if (kbuf->top_down) | |
431 | return locate_mem_hole_top_down(start, end, kbuf); | |
432 | return locate_mem_hole_bottom_up(start, end, kbuf); | |
433 | } | |
434 | ||
60fe3910 TJB |
435 | /** |
436 | * arch_kexec_walk_mem - call func(data) on free memory regions | |
437 | * @kbuf: Context info for the search. Also passed to @func. | |
438 | * @func: Function to call for each memory region. | |
439 | * | |
440 | * Return: The memory walk will stop when func returns a non-zero value | |
441 | * and that value will be returned. If all free regions are visited without | |
442 | * func returning non-zero, then zero will be returned. | |
443 | */ | |
444 | int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf, | |
445 | int (*func)(u64, u64, void *)) | |
446 | { | |
447 | if (kbuf->image->type == KEXEC_TYPE_CRASH) | |
448 | return walk_iomem_res_desc(crashk_res.desc, | |
449 | IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, | |
450 | crashk_res.start, crashk_res.end, | |
451 | kbuf, func); | |
452 | else | |
453 | return walk_system_ram_res(0, ULONG_MAX, kbuf, func); | |
454 | } | |
455 | ||
e2e806f9 TJB |
456 | /** |
457 | * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel | |
458 | * @kbuf: Parameters for the memory search. | |
459 | * | |
460 | * On success, kbuf->mem will have the start address of the memory region found. | |
461 | * | |
462 | * Return: 0 on success, negative errno on error. | |
463 | */ | |
464 | int kexec_locate_mem_hole(struct kexec_buf *kbuf) | |
465 | { | |
466 | int ret; | |
467 | ||
468 | ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback); | |
469 | ||
470 | return ret == 1 ? 0 : -EADDRNOTAVAIL; | |
471 | } | |
472 | ||
ec2b9bfa TJB |
473 | /** |
474 | * kexec_add_buffer - place a buffer in a kexec segment | |
475 | * @kbuf: Buffer contents and memory parameters. | |
476 | * | |
477 | * This function assumes that kexec_mutex is held. | |
478 | * On successful return, @kbuf->mem will have the physical address of | |
479 | * the buffer in memory. | |
480 | * | |
481 | * Return: 0 on success, negative errno on error. | |
a43cac0d | 482 | */ |
ec2b9bfa | 483 | int kexec_add_buffer(struct kexec_buf *kbuf) |
a43cac0d DY |
484 | { |
485 | ||
486 | struct kexec_segment *ksegment; | |
a43cac0d DY |
487 | int ret; |
488 | ||
489 | /* Currently adding segment this way is allowed only in file mode */ | |
ec2b9bfa | 490 | if (!kbuf->image->file_mode) |
a43cac0d DY |
491 | return -EINVAL; |
492 | ||
ec2b9bfa | 493 | if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) |
a43cac0d DY |
494 | return -EINVAL; |
495 | ||
496 | /* | |
497 | * Make sure we are not trying to add buffer after allocating | |
498 | * control pages. All segments need to be placed first before | |
499 | * any control pages are allocated. As control page allocation | |
500 | * logic goes through list of segments to make sure there are | |
501 | * no destination overlaps. | |
502 | */ | |
ec2b9bfa | 503 | if (!list_empty(&kbuf->image->control_pages)) { |
a43cac0d DY |
504 | WARN_ON(1); |
505 | return -EINVAL; | |
506 | } | |
507 | ||
ec2b9bfa TJB |
508 | /* Ensure minimum alignment needed for segments. */ |
509 | kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); | |
510 | kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); | |
a43cac0d DY |
511 | |
512 | /* Walk the RAM ranges and allocate a suitable range for the buffer */ | |
e2e806f9 TJB |
513 | ret = kexec_locate_mem_hole(kbuf); |
514 | if (ret) | |
515 | return ret; | |
a43cac0d DY |
516 | |
517 | /* Found a suitable memory range */ | |
ec2b9bfa | 518 | ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; |
a43cac0d DY |
519 | ksegment->kbuf = kbuf->buffer; |
520 | ksegment->bufsz = kbuf->bufsz; | |
521 | ksegment->mem = kbuf->mem; | |
522 | ksegment->memsz = kbuf->memsz; | |
ec2b9bfa | 523 | kbuf->image->nr_segments++; |
a43cac0d DY |
524 | return 0; |
525 | } | |
526 | ||
527 | /* Calculate and store the digest of segments */ | |
528 | static int kexec_calculate_store_digests(struct kimage *image) | |
529 | { | |
530 | struct crypto_shash *tfm; | |
531 | struct shash_desc *desc; | |
532 | int ret = 0, i, j, zero_buf_sz, sha_region_sz; | |
533 | size_t desc_size, nullsz; | |
534 | char *digest; | |
535 | void *zero_buf; | |
536 | struct kexec_sha_region *sha_regions; | |
537 | struct purgatory_info *pi = &image->purgatory_info; | |
538 | ||
539 | zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); | |
540 | zero_buf_sz = PAGE_SIZE; | |
541 | ||
542 | tfm = crypto_alloc_shash("sha256", 0, 0); | |
543 | if (IS_ERR(tfm)) { | |
544 | ret = PTR_ERR(tfm); | |
545 | goto out; | |
546 | } | |
547 | ||
548 | desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); | |
549 | desc = kzalloc(desc_size, GFP_KERNEL); | |
550 | if (!desc) { | |
551 | ret = -ENOMEM; | |
552 | goto out_free_tfm; | |
553 | } | |
554 | ||
555 | sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); | |
556 | sha_regions = vzalloc(sha_region_sz); | |
557 | if (!sha_regions) | |
558 | goto out_free_desc; | |
559 | ||
560 | desc->tfm = tfm; | |
561 | desc->flags = 0; | |
562 | ||
563 | ret = crypto_shash_init(desc); | |
564 | if (ret < 0) | |
565 | goto out_free_sha_regions; | |
566 | ||
567 | digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); | |
568 | if (!digest) { | |
569 | ret = -ENOMEM; | |
570 | goto out_free_sha_regions; | |
571 | } | |
572 | ||
573 | for (j = i = 0; i < image->nr_segments; i++) { | |
574 | struct kexec_segment *ksegment; | |
575 | ||
576 | ksegment = &image->segment[i]; | |
577 | /* | |
578 | * Skip purgatory as it will be modified once we put digest | |
579 | * info in purgatory. | |
580 | */ | |
581 | if (ksegment->kbuf == pi->purgatory_buf) | |
582 | continue; | |
583 | ||
584 | ret = crypto_shash_update(desc, ksegment->kbuf, | |
585 | ksegment->bufsz); | |
586 | if (ret) | |
587 | break; | |
588 | ||
589 | /* | |
590 | * Assume rest of the buffer is filled with zero and | |
591 | * update digest accordingly. | |
592 | */ | |
593 | nullsz = ksegment->memsz - ksegment->bufsz; | |
594 | while (nullsz) { | |
595 | unsigned long bytes = nullsz; | |
596 | ||
597 | if (bytes > zero_buf_sz) | |
598 | bytes = zero_buf_sz; | |
599 | ret = crypto_shash_update(desc, zero_buf, bytes); | |
600 | if (ret) | |
601 | break; | |
602 | nullsz -= bytes; | |
603 | } | |
604 | ||
605 | if (ret) | |
606 | break; | |
607 | ||
608 | sha_regions[j].start = ksegment->mem; | |
609 | sha_regions[j].len = ksegment->memsz; | |
610 | j++; | |
611 | } | |
612 | ||
613 | if (!ret) { | |
614 | ret = crypto_shash_final(desc, digest); | |
615 | if (ret) | |
616 | goto out_free_digest; | |
617 | ret = kexec_purgatory_get_set_symbol(image, "sha_regions", | |
618 | sha_regions, sha_region_sz, 0); | |
619 | if (ret) | |
620 | goto out_free_digest; | |
621 | ||
622 | ret = kexec_purgatory_get_set_symbol(image, "sha256_digest", | |
623 | digest, SHA256_DIGEST_SIZE, 0); | |
624 | if (ret) | |
625 | goto out_free_digest; | |
626 | } | |
627 | ||
628 | out_free_digest: | |
629 | kfree(digest); | |
630 | out_free_sha_regions: | |
631 | vfree(sha_regions); | |
632 | out_free_desc: | |
633 | kfree(desc); | |
634 | out_free_tfm: | |
635 | kfree(tfm); | |
636 | out: | |
637 | return ret; | |
638 | } | |
639 | ||
640 | /* Actually load purgatory. Lot of code taken from kexec-tools */ | |
641 | static int __kexec_load_purgatory(struct kimage *image, unsigned long min, | |
642 | unsigned long max, int top_down) | |
643 | { | |
644 | struct purgatory_info *pi = &image->purgatory_info; | |
ec2b9bfa TJB |
645 | unsigned long align, bss_align, bss_sz, bss_pad; |
646 | unsigned long entry, load_addr, curr_load_addr, bss_addr, offset; | |
a43cac0d DY |
647 | unsigned char *buf_addr, *src; |
648 | int i, ret = 0, entry_sidx = -1; | |
649 | const Elf_Shdr *sechdrs_c; | |
650 | Elf_Shdr *sechdrs = NULL; | |
ec2b9bfa TJB |
651 | struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1, |
652 | .buf_min = min, .buf_max = max, | |
653 | .top_down = top_down }; | |
a43cac0d DY |
654 | |
655 | /* | |
656 | * sechdrs_c points to section headers in purgatory and are read | |
657 | * only. No modifications allowed. | |
658 | */ | |
659 | sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff; | |
660 | ||
661 | /* | |
662 | * We can not modify sechdrs_c[] and its fields. It is read only. | |
663 | * Copy it over to a local copy where one can store some temporary | |
664 | * data and free it at the end. We need to modify ->sh_addr and | |
665 | * ->sh_offset fields to keep track of permanent and temporary | |
666 | * locations of sections. | |
667 | */ | |
668 | sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
669 | if (!sechdrs) | |
670 | return -ENOMEM; | |
671 | ||
672 | memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
673 | ||
674 | /* | |
675 | * We seem to have multiple copies of sections. First copy is which | |
676 | * is embedded in kernel in read only section. Some of these sections | |
677 | * will be copied to a temporary buffer and relocated. And these | |
678 | * sections will finally be copied to their final destination at | |
679 | * segment load time. | |
680 | * | |
681 | * Use ->sh_offset to reflect section address in memory. It will | |
682 | * point to original read only copy if section is not allocatable. | |
683 | * Otherwise it will point to temporary copy which will be relocated. | |
684 | * | |
685 | * Use ->sh_addr to contain final address of the section where it | |
686 | * will go during execution time. | |
687 | */ | |
688 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
689 | if (sechdrs[i].sh_type == SHT_NOBITS) | |
690 | continue; | |
691 | ||
692 | sechdrs[i].sh_offset = (unsigned long)pi->ehdr + | |
693 | sechdrs[i].sh_offset; | |
694 | } | |
695 | ||
696 | /* | |
697 | * Identify entry point section and make entry relative to section | |
698 | * start. | |
699 | */ | |
700 | entry = pi->ehdr->e_entry; | |
701 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
702 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
703 | continue; | |
704 | ||
705 | if (!(sechdrs[i].sh_flags & SHF_EXECINSTR)) | |
706 | continue; | |
707 | ||
708 | /* Make entry section relative */ | |
709 | if (sechdrs[i].sh_addr <= pi->ehdr->e_entry && | |
710 | ((sechdrs[i].sh_addr + sechdrs[i].sh_size) > | |
711 | pi->ehdr->e_entry)) { | |
712 | entry_sidx = i; | |
713 | entry -= sechdrs[i].sh_addr; | |
714 | break; | |
715 | } | |
716 | } | |
717 | ||
718 | /* Determine how much memory is needed to load relocatable object. */ | |
a43cac0d | 719 | bss_align = 1; |
a43cac0d DY |
720 | bss_sz = 0; |
721 | ||
722 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
723 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
724 | continue; | |
725 | ||
726 | align = sechdrs[i].sh_addralign; | |
727 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
ec2b9bfa TJB |
728 | if (kbuf.buf_align < align) |
729 | kbuf.buf_align = align; | |
730 | kbuf.bufsz = ALIGN(kbuf.bufsz, align); | |
731 | kbuf.bufsz += sechdrs[i].sh_size; | |
a43cac0d DY |
732 | } else { |
733 | /* bss section */ | |
734 | if (bss_align < align) | |
735 | bss_align = align; | |
736 | bss_sz = ALIGN(bss_sz, align); | |
737 | bss_sz += sechdrs[i].sh_size; | |
738 | } | |
739 | } | |
740 | ||
741 | /* Determine the bss padding required to align bss properly */ | |
742 | bss_pad = 0; | |
ec2b9bfa TJB |
743 | if (kbuf.bufsz & (bss_align - 1)) |
744 | bss_pad = bss_align - (kbuf.bufsz & (bss_align - 1)); | |
a43cac0d | 745 | |
ec2b9bfa | 746 | kbuf.memsz = kbuf.bufsz + bss_pad + bss_sz; |
a43cac0d DY |
747 | |
748 | /* Allocate buffer for purgatory */ | |
ec2b9bfa TJB |
749 | kbuf.buffer = vzalloc(kbuf.bufsz); |
750 | if (!kbuf.buffer) { | |
a43cac0d DY |
751 | ret = -ENOMEM; |
752 | goto out; | |
753 | } | |
754 | ||
ec2b9bfa TJB |
755 | if (kbuf.buf_align < bss_align) |
756 | kbuf.buf_align = bss_align; | |
a43cac0d DY |
757 | |
758 | /* Add buffer to segment list */ | |
ec2b9bfa | 759 | ret = kexec_add_buffer(&kbuf); |
a43cac0d DY |
760 | if (ret) |
761 | goto out; | |
ec2b9bfa | 762 | pi->purgatory_load_addr = kbuf.mem; |
a43cac0d DY |
763 | |
764 | /* Load SHF_ALLOC sections */ | |
ec2b9bfa | 765 | buf_addr = kbuf.buffer; |
a43cac0d | 766 | load_addr = curr_load_addr = pi->purgatory_load_addr; |
ec2b9bfa | 767 | bss_addr = load_addr + kbuf.bufsz + bss_pad; |
a43cac0d DY |
768 | |
769 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
770 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
771 | continue; | |
772 | ||
773 | align = sechdrs[i].sh_addralign; | |
774 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
775 | curr_load_addr = ALIGN(curr_load_addr, align); | |
776 | offset = curr_load_addr - load_addr; | |
777 | /* We already modifed ->sh_offset to keep src addr */ | |
778 | src = (char *) sechdrs[i].sh_offset; | |
779 | memcpy(buf_addr + offset, src, sechdrs[i].sh_size); | |
780 | ||
781 | /* Store load address and source address of section */ | |
782 | sechdrs[i].sh_addr = curr_load_addr; | |
783 | ||
784 | /* | |
785 | * This section got copied to temporary buffer. Update | |
786 | * ->sh_offset accordingly. | |
787 | */ | |
788 | sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset); | |
789 | ||
790 | /* Advance to the next address */ | |
791 | curr_load_addr += sechdrs[i].sh_size; | |
792 | } else { | |
793 | bss_addr = ALIGN(bss_addr, align); | |
794 | sechdrs[i].sh_addr = bss_addr; | |
795 | bss_addr += sechdrs[i].sh_size; | |
796 | } | |
797 | } | |
798 | ||
799 | /* Update entry point based on load address of text section */ | |
800 | if (entry_sidx >= 0) | |
801 | entry += sechdrs[entry_sidx].sh_addr; | |
802 | ||
803 | /* Make kernel jump to purgatory after shutdown */ | |
804 | image->start = entry; | |
805 | ||
806 | /* Used later to get/set symbol values */ | |
807 | pi->sechdrs = sechdrs; | |
808 | ||
809 | /* | |
810 | * Used later to identify which section is purgatory and skip it | |
811 | * from checksumming. | |
812 | */ | |
ec2b9bfa | 813 | pi->purgatory_buf = kbuf.buffer; |
a43cac0d DY |
814 | return ret; |
815 | out: | |
816 | vfree(sechdrs); | |
ec2b9bfa | 817 | vfree(kbuf.buffer); |
a43cac0d DY |
818 | return ret; |
819 | } | |
820 | ||
821 | static int kexec_apply_relocations(struct kimage *image) | |
822 | { | |
823 | int i, ret; | |
824 | struct purgatory_info *pi = &image->purgatory_info; | |
825 | Elf_Shdr *sechdrs = pi->sechdrs; | |
826 | ||
827 | /* Apply relocations */ | |
828 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
829 | Elf_Shdr *section, *symtab; | |
830 | ||
831 | if (sechdrs[i].sh_type != SHT_RELA && | |
832 | sechdrs[i].sh_type != SHT_REL) | |
833 | continue; | |
834 | ||
835 | /* | |
836 | * For section of type SHT_RELA/SHT_REL, | |
837 | * ->sh_link contains section header index of associated | |
838 | * symbol table. And ->sh_info contains section header | |
839 | * index of section to which relocations apply. | |
840 | */ | |
841 | if (sechdrs[i].sh_info >= pi->ehdr->e_shnum || | |
842 | sechdrs[i].sh_link >= pi->ehdr->e_shnum) | |
843 | return -ENOEXEC; | |
844 | ||
845 | section = &sechdrs[sechdrs[i].sh_info]; | |
846 | symtab = &sechdrs[sechdrs[i].sh_link]; | |
847 | ||
848 | if (!(section->sh_flags & SHF_ALLOC)) | |
849 | continue; | |
850 | ||
851 | /* | |
852 | * symtab->sh_link contain section header index of associated | |
853 | * string table. | |
854 | */ | |
855 | if (symtab->sh_link >= pi->ehdr->e_shnum) | |
856 | /* Invalid section number? */ | |
857 | continue; | |
858 | ||
859 | /* | |
860 | * Respective architecture needs to provide support for applying | |
861 | * relocations of type SHT_RELA/SHT_REL. | |
862 | */ | |
863 | if (sechdrs[i].sh_type == SHT_RELA) | |
864 | ret = arch_kexec_apply_relocations_add(pi->ehdr, | |
865 | sechdrs, i); | |
866 | else if (sechdrs[i].sh_type == SHT_REL) | |
867 | ret = arch_kexec_apply_relocations(pi->ehdr, | |
868 | sechdrs, i); | |
869 | if (ret) | |
870 | return ret; | |
871 | } | |
872 | ||
873 | return 0; | |
874 | } | |
875 | ||
876 | /* Load relocatable purgatory object and relocate it appropriately */ | |
877 | int kexec_load_purgatory(struct kimage *image, unsigned long min, | |
878 | unsigned long max, int top_down, | |
879 | unsigned long *load_addr) | |
880 | { | |
881 | struct purgatory_info *pi = &image->purgatory_info; | |
882 | int ret; | |
883 | ||
884 | if (kexec_purgatory_size <= 0) | |
885 | return -EINVAL; | |
886 | ||
887 | if (kexec_purgatory_size < sizeof(Elf_Ehdr)) | |
888 | return -ENOEXEC; | |
889 | ||
890 | pi->ehdr = (Elf_Ehdr *)kexec_purgatory; | |
891 | ||
892 | if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0 | |
893 | || pi->ehdr->e_type != ET_REL | |
894 | || !elf_check_arch(pi->ehdr) | |
895 | || pi->ehdr->e_shentsize != sizeof(Elf_Shdr)) | |
896 | return -ENOEXEC; | |
897 | ||
898 | if (pi->ehdr->e_shoff >= kexec_purgatory_size | |
899 | || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) > | |
900 | kexec_purgatory_size - pi->ehdr->e_shoff)) | |
901 | return -ENOEXEC; | |
902 | ||
903 | ret = __kexec_load_purgatory(image, min, max, top_down); | |
904 | if (ret) | |
905 | return ret; | |
906 | ||
907 | ret = kexec_apply_relocations(image); | |
908 | if (ret) | |
909 | goto out; | |
910 | ||
911 | *load_addr = pi->purgatory_load_addr; | |
912 | return 0; | |
913 | out: | |
914 | vfree(pi->sechdrs); | |
070c43ee TJB |
915 | pi->sechdrs = NULL; |
916 | ||
a43cac0d | 917 | vfree(pi->purgatory_buf); |
070c43ee | 918 | pi->purgatory_buf = NULL; |
a43cac0d DY |
919 | return ret; |
920 | } | |
921 | ||
922 | static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, | |
923 | const char *name) | |
924 | { | |
925 | Elf_Sym *syms; | |
926 | Elf_Shdr *sechdrs; | |
927 | Elf_Ehdr *ehdr; | |
928 | int i, k; | |
929 | const char *strtab; | |
930 | ||
931 | if (!pi->sechdrs || !pi->ehdr) | |
932 | return NULL; | |
933 | ||
934 | sechdrs = pi->sechdrs; | |
935 | ehdr = pi->ehdr; | |
936 | ||
937 | for (i = 0; i < ehdr->e_shnum; i++) { | |
938 | if (sechdrs[i].sh_type != SHT_SYMTAB) | |
939 | continue; | |
940 | ||
941 | if (sechdrs[i].sh_link >= ehdr->e_shnum) | |
942 | /* Invalid strtab section number */ | |
943 | continue; | |
944 | strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset; | |
945 | syms = (Elf_Sym *)sechdrs[i].sh_offset; | |
946 | ||
947 | /* Go through symbols for a match */ | |
948 | for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { | |
949 | if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) | |
950 | continue; | |
951 | ||
952 | if (strcmp(strtab + syms[k].st_name, name) != 0) | |
953 | continue; | |
954 | ||
955 | if (syms[k].st_shndx == SHN_UNDEF || | |
956 | syms[k].st_shndx >= ehdr->e_shnum) { | |
957 | pr_debug("Symbol: %s has bad section index %d.\n", | |
958 | name, syms[k].st_shndx); | |
959 | return NULL; | |
960 | } | |
961 | ||
962 | /* Found the symbol we are looking for */ | |
963 | return &syms[k]; | |
964 | } | |
965 | } | |
966 | ||
967 | return NULL; | |
968 | } | |
969 | ||
970 | void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) | |
971 | { | |
972 | struct purgatory_info *pi = &image->purgatory_info; | |
973 | Elf_Sym *sym; | |
974 | Elf_Shdr *sechdr; | |
975 | ||
976 | sym = kexec_purgatory_find_symbol(pi, name); | |
977 | if (!sym) | |
978 | return ERR_PTR(-EINVAL); | |
979 | ||
980 | sechdr = &pi->sechdrs[sym->st_shndx]; | |
981 | ||
982 | /* | |
983 | * Returns the address where symbol will finally be loaded after | |
984 | * kexec_load_segment() | |
985 | */ | |
986 | return (void *)(sechdr->sh_addr + sym->st_value); | |
987 | } | |
988 | ||
989 | /* | |
990 | * Get or set value of a symbol. If "get_value" is true, symbol value is | |
991 | * returned in buf otherwise symbol value is set based on value in buf. | |
992 | */ | |
993 | int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, | |
994 | void *buf, unsigned int size, bool get_value) | |
995 | { | |
996 | Elf_Sym *sym; | |
997 | Elf_Shdr *sechdrs; | |
998 | struct purgatory_info *pi = &image->purgatory_info; | |
999 | char *sym_buf; | |
1000 | ||
1001 | sym = kexec_purgatory_find_symbol(pi, name); | |
1002 | if (!sym) | |
1003 | return -EINVAL; | |
1004 | ||
1005 | if (sym->st_size != size) { | |
1006 | pr_err("symbol %s size mismatch: expected %lu actual %u\n", | |
1007 | name, (unsigned long)sym->st_size, size); | |
1008 | return -EINVAL; | |
1009 | } | |
1010 | ||
1011 | sechdrs = pi->sechdrs; | |
1012 | ||
1013 | if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) { | |
1014 | pr_err("symbol %s is in a bss section. Cannot %s\n", name, | |
1015 | get_value ? "get" : "set"); | |
1016 | return -EINVAL; | |
1017 | } | |
1018 | ||
1019 | sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset + | |
1020 | sym->st_value; | |
1021 | ||
1022 | if (get_value) | |
1023 | memcpy((void *)buf, sym_buf, size); | |
1024 | else | |
1025 | memcpy((void *)sym_buf, buf, size); | |
1026 | ||
1027 | return 0; | |
1028 | } |