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> |
a43cac0d DY |
22 | #include <crypto/hash.h> |
23 | #include <crypto/sha.h> | |
24 | #include <linux/syscalls.h> | |
25 | #include <linux/vmalloc.h> | |
26 | #include "kexec_internal.h" | |
27 | ||
28 | /* | |
29 | * Declare these symbols weak so that if architecture provides a purgatory, | |
30 | * these will be overridden. | |
31 | */ | |
32 | char __weak kexec_purgatory[0]; | |
33 | size_t __weak kexec_purgatory_size = 0; | |
34 | ||
35 | static int kexec_calculate_store_digests(struct kimage *image); | |
36 | ||
a43cac0d DY |
37 | /* Architectures can provide this probe function */ |
38 | int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, | |
39 | unsigned long buf_len) | |
40 | { | |
41 | return -ENOEXEC; | |
42 | } | |
43 | ||
44 | void * __weak arch_kexec_kernel_image_load(struct kimage *image) | |
45 | { | |
46 | return ERR_PTR(-ENOEXEC); | |
47 | } | |
48 | ||
49 | int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) | |
50 | { | |
51 | return -EINVAL; | |
52 | } | |
53 | ||
978e30c9 | 54 | #ifdef CONFIG_KEXEC_VERIFY_SIG |
a43cac0d DY |
55 | int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, |
56 | unsigned long buf_len) | |
57 | { | |
58 | return -EKEYREJECTED; | |
59 | } | |
978e30c9 | 60 | #endif |
a43cac0d DY |
61 | |
62 | /* Apply relocations of type RELA */ | |
63 | int __weak | |
64 | arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
65 | unsigned int relsec) | |
66 | { | |
67 | pr_err("RELA relocation unsupported.\n"); | |
68 | return -ENOEXEC; | |
69 | } | |
70 | ||
71 | /* Apply relocations of type REL */ | |
72 | int __weak | |
73 | arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
74 | unsigned int relsec) | |
75 | { | |
76 | pr_err("REL relocation unsupported.\n"); | |
77 | return -ENOEXEC; | |
78 | } | |
79 | ||
80 | /* | |
81 | * Free up memory used by kernel, initrd, and command line. This is temporary | |
82 | * memory allocation which is not needed any more after these buffers have | |
83 | * been loaded into separate segments and have been copied elsewhere. | |
84 | */ | |
85 | void kimage_file_post_load_cleanup(struct kimage *image) | |
86 | { | |
87 | struct purgatory_info *pi = &image->purgatory_info; | |
88 | ||
89 | vfree(image->kernel_buf); | |
90 | image->kernel_buf = NULL; | |
91 | ||
92 | vfree(image->initrd_buf); | |
93 | image->initrd_buf = NULL; | |
94 | ||
95 | kfree(image->cmdline_buf); | |
96 | image->cmdline_buf = NULL; | |
97 | ||
98 | vfree(pi->purgatory_buf); | |
99 | pi->purgatory_buf = NULL; | |
100 | ||
101 | vfree(pi->sechdrs); | |
102 | pi->sechdrs = NULL; | |
103 | ||
104 | /* See if architecture has anything to cleanup post load */ | |
105 | arch_kimage_file_post_load_cleanup(image); | |
106 | ||
107 | /* | |
108 | * Above call should have called into bootloader to free up | |
109 | * any data stored in kimage->image_loader_data. It should | |
110 | * be ok now to free it up. | |
111 | */ | |
112 | kfree(image->image_loader_data); | |
113 | image->image_loader_data = NULL; | |
114 | } | |
115 | ||
116 | /* | |
117 | * In file mode list of segments is prepared by kernel. Copy relevant | |
118 | * data from user space, do error checking, prepare segment list | |
119 | */ | |
120 | static int | |
121 | kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, | |
122 | const char __user *cmdline_ptr, | |
123 | unsigned long cmdline_len, unsigned flags) | |
124 | { | |
125 | int ret = 0; | |
126 | void *ldata; | |
b804defe | 127 | loff_t size; |
a43cac0d | 128 | |
b804defe MZ |
129 | ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, |
130 | &size, INT_MAX, READING_KEXEC_IMAGE); | |
a43cac0d DY |
131 | if (ret) |
132 | return ret; | |
b804defe | 133 | image->kernel_buf_len = size; |
a43cac0d DY |
134 | |
135 | /* Call arch image probe handlers */ | |
136 | ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, | |
137 | image->kernel_buf_len); | |
a43cac0d DY |
138 | if (ret) |
139 | goto out; | |
140 | ||
141 | #ifdef CONFIG_KEXEC_VERIFY_SIG | |
142 | ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, | |
143 | image->kernel_buf_len); | |
144 | if (ret) { | |
145 | pr_debug("kernel signature verification failed.\n"); | |
146 | goto out; | |
147 | } | |
148 | pr_debug("kernel signature verification successful.\n"); | |
149 | #endif | |
150 | /* It is possible that there no initramfs is being loaded */ | |
151 | if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { | |
b804defe MZ |
152 | ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, |
153 | &size, INT_MAX, | |
154 | READING_KEXEC_INITRAMFS); | |
a43cac0d DY |
155 | if (ret) |
156 | goto out; | |
b804defe | 157 | image->initrd_buf_len = size; |
a43cac0d DY |
158 | } |
159 | ||
160 | if (cmdline_len) { | |
161 | image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL); | |
162 | if (!image->cmdline_buf) { | |
163 | ret = -ENOMEM; | |
164 | goto out; | |
165 | } | |
166 | ||
167 | ret = copy_from_user(image->cmdline_buf, cmdline_ptr, | |
168 | cmdline_len); | |
169 | if (ret) { | |
170 | ret = -EFAULT; | |
171 | goto out; | |
172 | } | |
173 | ||
174 | image->cmdline_buf_len = cmdline_len; | |
175 | ||
176 | /* command line should be a string with last byte null */ | |
177 | if (image->cmdline_buf[cmdline_len - 1] != '\0') { | |
178 | ret = -EINVAL; | |
179 | goto out; | |
180 | } | |
181 | } | |
182 | ||
183 | /* Call arch image load handlers */ | |
184 | ldata = arch_kexec_kernel_image_load(image); | |
185 | ||
186 | if (IS_ERR(ldata)) { | |
187 | ret = PTR_ERR(ldata); | |
188 | goto out; | |
189 | } | |
190 | ||
191 | image->image_loader_data = ldata; | |
192 | out: | |
193 | /* In case of error, free up all allocated memory in this function */ | |
194 | if (ret) | |
195 | kimage_file_post_load_cleanup(image); | |
196 | return ret; | |
197 | } | |
198 | ||
199 | static int | |
200 | kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, | |
201 | int initrd_fd, const char __user *cmdline_ptr, | |
202 | unsigned long cmdline_len, unsigned long flags) | |
203 | { | |
204 | int ret; | |
205 | struct kimage *image; | |
206 | bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; | |
207 | ||
208 | image = do_kimage_alloc_init(); | |
209 | if (!image) | |
210 | return -ENOMEM; | |
211 | ||
212 | image->file_mode = 1; | |
213 | ||
214 | if (kexec_on_panic) { | |
215 | /* Enable special crash kernel control page alloc policy. */ | |
216 | image->control_page = crashk_res.start; | |
217 | image->type = KEXEC_TYPE_CRASH; | |
218 | } | |
219 | ||
220 | ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, | |
221 | cmdline_ptr, cmdline_len, flags); | |
222 | if (ret) | |
223 | goto out_free_image; | |
224 | ||
225 | ret = sanity_check_segment_list(image); | |
226 | if (ret) | |
227 | goto out_free_post_load_bufs; | |
228 | ||
229 | ret = -ENOMEM; | |
230 | image->control_code_page = kimage_alloc_control_pages(image, | |
231 | get_order(KEXEC_CONTROL_PAGE_SIZE)); | |
232 | if (!image->control_code_page) { | |
233 | pr_err("Could not allocate control_code_buffer\n"); | |
234 | goto out_free_post_load_bufs; | |
235 | } | |
236 | ||
237 | if (!kexec_on_panic) { | |
238 | image->swap_page = kimage_alloc_control_pages(image, 0); | |
239 | if (!image->swap_page) { | |
240 | pr_err("Could not allocate swap buffer\n"); | |
241 | goto out_free_control_pages; | |
242 | } | |
243 | } | |
244 | ||
245 | *rimage = image; | |
246 | return 0; | |
247 | out_free_control_pages: | |
248 | kimage_free_page_list(&image->control_pages); | |
249 | out_free_post_load_bufs: | |
250 | kimage_file_post_load_cleanup(image); | |
251 | out_free_image: | |
252 | kfree(image); | |
253 | return ret; | |
254 | } | |
255 | ||
256 | SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, | |
257 | unsigned long, cmdline_len, const char __user *, cmdline_ptr, | |
258 | unsigned long, flags) | |
259 | { | |
260 | int ret = 0, i; | |
261 | struct kimage **dest_image, *image; | |
262 | ||
263 | /* We only trust the superuser with rebooting the system. */ | |
264 | if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) | |
265 | return -EPERM; | |
266 | ||
267 | /* Make sure we have a legal set of flags */ | |
268 | if (flags != (flags & KEXEC_FILE_FLAGS)) | |
269 | return -EINVAL; | |
270 | ||
271 | image = NULL; | |
272 | ||
273 | if (!mutex_trylock(&kexec_mutex)) | |
274 | return -EBUSY; | |
275 | ||
276 | dest_image = &kexec_image; | |
9b492cf5 | 277 | if (flags & KEXEC_FILE_ON_CRASH) { |
a43cac0d | 278 | dest_image = &kexec_crash_image; |
9b492cf5 XP |
279 | if (kexec_crash_image) |
280 | arch_kexec_unprotect_crashkres(); | |
281 | } | |
a43cac0d DY |
282 | |
283 | if (flags & KEXEC_FILE_UNLOAD) | |
284 | goto exchange; | |
285 | ||
286 | /* | |
287 | * In case of crash, new kernel gets loaded in reserved region. It is | |
288 | * same memory where old crash kernel might be loaded. Free any | |
289 | * current crash dump kernel before we corrupt it. | |
290 | */ | |
291 | if (flags & KEXEC_FILE_ON_CRASH) | |
292 | kimage_free(xchg(&kexec_crash_image, NULL)); | |
293 | ||
294 | ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, | |
295 | cmdline_len, flags); | |
296 | if (ret) | |
297 | goto out; | |
298 | ||
299 | ret = machine_kexec_prepare(image); | |
300 | if (ret) | |
301 | goto out; | |
302 | ||
303 | ret = kexec_calculate_store_digests(image); | |
304 | if (ret) | |
305 | goto out; | |
306 | ||
307 | for (i = 0; i < image->nr_segments; i++) { | |
308 | struct kexec_segment *ksegment; | |
309 | ||
310 | ksegment = &image->segment[i]; | |
311 | pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", | |
312 | i, ksegment->buf, ksegment->bufsz, ksegment->mem, | |
313 | ksegment->memsz); | |
314 | ||
315 | ret = kimage_load_segment(image, &image->segment[i]); | |
316 | if (ret) | |
317 | goto out; | |
318 | } | |
319 | ||
320 | kimage_terminate(image); | |
321 | ||
322 | /* | |
323 | * Free up any temporary buffers allocated which are not needed | |
324 | * after image has been loaded | |
325 | */ | |
326 | kimage_file_post_load_cleanup(image); | |
327 | exchange: | |
328 | image = xchg(dest_image, image); | |
329 | out: | |
9b492cf5 XP |
330 | if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) |
331 | arch_kexec_protect_crashkres(); | |
332 | ||
a43cac0d DY |
333 | mutex_unlock(&kexec_mutex); |
334 | kimage_free(image); | |
335 | return ret; | |
336 | } | |
337 | ||
338 | static int locate_mem_hole_top_down(unsigned long start, unsigned long end, | |
339 | struct kexec_buf *kbuf) | |
340 | { | |
341 | struct kimage *image = kbuf->image; | |
342 | unsigned long temp_start, temp_end; | |
343 | ||
344 | temp_end = min(end, kbuf->buf_max); | |
345 | temp_start = temp_end - kbuf->memsz; | |
346 | ||
347 | do { | |
348 | /* align down start */ | |
349 | temp_start = temp_start & (~(kbuf->buf_align - 1)); | |
350 | ||
351 | if (temp_start < start || temp_start < kbuf->buf_min) | |
352 | return 0; | |
353 | ||
354 | temp_end = temp_start + kbuf->memsz - 1; | |
355 | ||
356 | /* | |
357 | * Make sure this does not conflict with any of existing | |
358 | * segments | |
359 | */ | |
360 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
361 | temp_start = temp_start - PAGE_SIZE; | |
362 | continue; | |
363 | } | |
364 | ||
365 | /* We found a suitable memory range */ | |
366 | break; | |
367 | } while (1); | |
368 | ||
369 | /* If we are here, we found a suitable memory range */ | |
370 | kbuf->mem = temp_start; | |
371 | ||
372 | /* Success, stop navigating through remaining System RAM ranges */ | |
373 | return 1; | |
374 | } | |
375 | ||
376 | static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, | |
377 | struct kexec_buf *kbuf) | |
378 | { | |
379 | struct kimage *image = kbuf->image; | |
380 | unsigned long temp_start, temp_end; | |
381 | ||
382 | temp_start = max(start, kbuf->buf_min); | |
383 | ||
384 | do { | |
385 | temp_start = ALIGN(temp_start, kbuf->buf_align); | |
386 | temp_end = temp_start + kbuf->memsz - 1; | |
387 | ||
388 | if (temp_end > end || temp_end > kbuf->buf_max) | |
389 | return 0; | |
390 | /* | |
391 | * Make sure this does not conflict with any of existing | |
392 | * segments | |
393 | */ | |
394 | if (kimage_is_destination_range(image, temp_start, temp_end)) { | |
395 | temp_start = temp_start + PAGE_SIZE; | |
396 | continue; | |
397 | } | |
398 | ||
399 | /* We found a suitable memory range */ | |
400 | break; | |
401 | } while (1); | |
402 | ||
403 | /* If we are here, we found a suitable memory range */ | |
404 | kbuf->mem = temp_start; | |
405 | ||
406 | /* Success, stop navigating through remaining System RAM ranges */ | |
407 | return 1; | |
408 | } | |
409 | ||
410 | static int locate_mem_hole_callback(u64 start, u64 end, void *arg) | |
411 | { | |
412 | struct kexec_buf *kbuf = (struct kexec_buf *)arg; | |
413 | unsigned long sz = end - start + 1; | |
414 | ||
415 | /* Returning 0 will take to next memory range */ | |
416 | if (sz < kbuf->memsz) | |
417 | return 0; | |
418 | ||
419 | if (end < kbuf->buf_min || start > kbuf->buf_max) | |
420 | return 0; | |
421 | ||
422 | /* | |
423 | * Allocate memory top down with-in ram range. Otherwise bottom up | |
424 | * allocation. | |
425 | */ | |
426 | if (kbuf->top_down) | |
427 | return locate_mem_hole_top_down(start, end, kbuf); | |
428 | return locate_mem_hole_bottom_up(start, end, kbuf); | |
429 | } | |
430 | ||
431 | /* | |
432 | * Helper function for placing a buffer in a kexec segment. This assumes | |
433 | * that kexec_mutex is held. | |
434 | */ | |
435 | int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz, | |
436 | unsigned long memsz, unsigned long buf_align, | |
437 | unsigned long buf_min, unsigned long buf_max, | |
438 | bool top_down, unsigned long *load_addr) | |
439 | { | |
440 | ||
441 | struct kexec_segment *ksegment; | |
442 | struct kexec_buf buf, *kbuf; | |
443 | int ret; | |
444 | ||
445 | /* Currently adding segment this way is allowed only in file mode */ | |
446 | if (!image->file_mode) | |
447 | return -EINVAL; | |
448 | ||
449 | if (image->nr_segments >= KEXEC_SEGMENT_MAX) | |
450 | return -EINVAL; | |
451 | ||
452 | /* | |
453 | * Make sure we are not trying to add buffer after allocating | |
454 | * control pages. All segments need to be placed first before | |
455 | * any control pages are allocated. As control page allocation | |
456 | * logic goes through list of segments to make sure there are | |
457 | * no destination overlaps. | |
458 | */ | |
459 | if (!list_empty(&image->control_pages)) { | |
460 | WARN_ON(1); | |
461 | return -EINVAL; | |
462 | } | |
463 | ||
464 | memset(&buf, 0, sizeof(struct kexec_buf)); | |
465 | kbuf = &buf; | |
466 | kbuf->image = image; | |
467 | kbuf->buffer = buffer; | |
468 | kbuf->bufsz = bufsz; | |
469 | ||
470 | kbuf->memsz = ALIGN(memsz, PAGE_SIZE); | |
471 | kbuf->buf_align = max(buf_align, PAGE_SIZE); | |
472 | kbuf->buf_min = buf_min; | |
473 | kbuf->buf_max = buf_max; | |
474 | kbuf->top_down = top_down; | |
475 | ||
476 | /* Walk the RAM ranges and allocate a suitable range for the buffer */ | |
477 | if (image->type == KEXEC_TYPE_CRASH) | |
f0f4711a TK |
478 | ret = walk_iomem_res_desc(crashk_res.desc, |
479 | IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, | |
480 | crashk_res.start, crashk_res.end, kbuf, | |
481 | locate_mem_hole_callback); | |
a43cac0d DY |
482 | else |
483 | ret = walk_system_ram_res(0, -1, kbuf, | |
484 | locate_mem_hole_callback); | |
485 | if (ret != 1) { | |
486 | /* A suitable memory range could not be found for buffer */ | |
487 | return -EADDRNOTAVAIL; | |
488 | } | |
489 | ||
490 | /* Found a suitable memory range */ | |
491 | ksegment = &image->segment[image->nr_segments]; | |
492 | ksegment->kbuf = kbuf->buffer; | |
493 | ksegment->bufsz = kbuf->bufsz; | |
494 | ksegment->mem = kbuf->mem; | |
495 | ksegment->memsz = kbuf->memsz; | |
496 | image->nr_segments++; | |
497 | *load_addr = ksegment->mem; | |
498 | return 0; | |
499 | } | |
500 | ||
501 | /* Calculate and store the digest of segments */ | |
502 | static int kexec_calculate_store_digests(struct kimage *image) | |
503 | { | |
504 | struct crypto_shash *tfm; | |
505 | struct shash_desc *desc; | |
506 | int ret = 0, i, j, zero_buf_sz, sha_region_sz; | |
507 | size_t desc_size, nullsz; | |
508 | char *digest; | |
509 | void *zero_buf; | |
510 | struct kexec_sha_region *sha_regions; | |
511 | struct purgatory_info *pi = &image->purgatory_info; | |
512 | ||
513 | zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); | |
514 | zero_buf_sz = PAGE_SIZE; | |
515 | ||
516 | tfm = crypto_alloc_shash("sha256", 0, 0); | |
517 | if (IS_ERR(tfm)) { | |
518 | ret = PTR_ERR(tfm); | |
519 | goto out; | |
520 | } | |
521 | ||
522 | desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); | |
523 | desc = kzalloc(desc_size, GFP_KERNEL); | |
524 | if (!desc) { | |
525 | ret = -ENOMEM; | |
526 | goto out_free_tfm; | |
527 | } | |
528 | ||
529 | sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); | |
530 | sha_regions = vzalloc(sha_region_sz); | |
531 | if (!sha_regions) | |
532 | goto out_free_desc; | |
533 | ||
534 | desc->tfm = tfm; | |
535 | desc->flags = 0; | |
536 | ||
537 | ret = crypto_shash_init(desc); | |
538 | if (ret < 0) | |
539 | goto out_free_sha_regions; | |
540 | ||
541 | digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); | |
542 | if (!digest) { | |
543 | ret = -ENOMEM; | |
544 | goto out_free_sha_regions; | |
545 | } | |
546 | ||
547 | for (j = i = 0; i < image->nr_segments; i++) { | |
548 | struct kexec_segment *ksegment; | |
549 | ||
550 | ksegment = &image->segment[i]; | |
551 | /* | |
552 | * Skip purgatory as it will be modified once we put digest | |
553 | * info in purgatory. | |
554 | */ | |
555 | if (ksegment->kbuf == pi->purgatory_buf) | |
556 | continue; | |
557 | ||
558 | ret = crypto_shash_update(desc, ksegment->kbuf, | |
559 | ksegment->bufsz); | |
560 | if (ret) | |
561 | break; | |
562 | ||
563 | /* | |
564 | * Assume rest of the buffer is filled with zero and | |
565 | * update digest accordingly. | |
566 | */ | |
567 | nullsz = ksegment->memsz - ksegment->bufsz; | |
568 | while (nullsz) { | |
569 | unsigned long bytes = nullsz; | |
570 | ||
571 | if (bytes > zero_buf_sz) | |
572 | bytes = zero_buf_sz; | |
573 | ret = crypto_shash_update(desc, zero_buf, bytes); | |
574 | if (ret) | |
575 | break; | |
576 | nullsz -= bytes; | |
577 | } | |
578 | ||
579 | if (ret) | |
580 | break; | |
581 | ||
582 | sha_regions[j].start = ksegment->mem; | |
583 | sha_regions[j].len = ksegment->memsz; | |
584 | j++; | |
585 | } | |
586 | ||
587 | if (!ret) { | |
588 | ret = crypto_shash_final(desc, digest); | |
589 | if (ret) | |
590 | goto out_free_digest; | |
591 | ret = kexec_purgatory_get_set_symbol(image, "sha_regions", | |
592 | sha_regions, sha_region_sz, 0); | |
593 | if (ret) | |
594 | goto out_free_digest; | |
595 | ||
596 | ret = kexec_purgatory_get_set_symbol(image, "sha256_digest", | |
597 | digest, SHA256_DIGEST_SIZE, 0); | |
598 | if (ret) | |
599 | goto out_free_digest; | |
600 | } | |
601 | ||
602 | out_free_digest: | |
603 | kfree(digest); | |
604 | out_free_sha_regions: | |
605 | vfree(sha_regions); | |
606 | out_free_desc: | |
607 | kfree(desc); | |
608 | out_free_tfm: | |
609 | kfree(tfm); | |
610 | out: | |
611 | return ret; | |
612 | } | |
613 | ||
614 | /* Actually load purgatory. Lot of code taken from kexec-tools */ | |
615 | static int __kexec_load_purgatory(struct kimage *image, unsigned long min, | |
616 | unsigned long max, int top_down) | |
617 | { | |
618 | struct purgatory_info *pi = &image->purgatory_info; | |
619 | unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad; | |
620 | unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset; | |
621 | unsigned char *buf_addr, *src; | |
622 | int i, ret = 0, entry_sidx = -1; | |
623 | const Elf_Shdr *sechdrs_c; | |
624 | Elf_Shdr *sechdrs = NULL; | |
625 | void *purgatory_buf = NULL; | |
626 | ||
627 | /* | |
628 | * sechdrs_c points to section headers in purgatory and are read | |
629 | * only. No modifications allowed. | |
630 | */ | |
631 | sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff; | |
632 | ||
633 | /* | |
634 | * We can not modify sechdrs_c[] and its fields. It is read only. | |
635 | * Copy it over to a local copy where one can store some temporary | |
636 | * data and free it at the end. We need to modify ->sh_addr and | |
637 | * ->sh_offset fields to keep track of permanent and temporary | |
638 | * locations of sections. | |
639 | */ | |
640 | sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
641 | if (!sechdrs) | |
642 | return -ENOMEM; | |
643 | ||
644 | memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr)); | |
645 | ||
646 | /* | |
647 | * We seem to have multiple copies of sections. First copy is which | |
648 | * is embedded in kernel in read only section. Some of these sections | |
649 | * will be copied to a temporary buffer and relocated. And these | |
650 | * sections will finally be copied to their final destination at | |
651 | * segment load time. | |
652 | * | |
653 | * Use ->sh_offset to reflect section address in memory. It will | |
654 | * point to original read only copy if section is not allocatable. | |
655 | * Otherwise it will point to temporary copy which will be relocated. | |
656 | * | |
657 | * Use ->sh_addr to contain final address of the section where it | |
658 | * will go during execution time. | |
659 | */ | |
660 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
661 | if (sechdrs[i].sh_type == SHT_NOBITS) | |
662 | continue; | |
663 | ||
664 | sechdrs[i].sh_offset = (unsigned long)pi->ehdr + | |
665 | sechdrs[i].sh_offset; | |
666 | } | |
667 | ||
668 | /* | |
669 | * Identify entry point section and make entry relative to section | |
670 | * start. | |
671 | */ | |
672 | entry = pi->ehdr->e_entry; | |
673 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
674 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
675 | continue; | |
676 | ||
677 | if (!(sechdrs[i].sh_flags & SHF_EXECINSTR)) | |
678 | continue; | |
679 | ||
680 | /* Make entry section relative */ | |
681 | if (sechdrs[i].sh_addr <= pi->ehdr->e_entry && | |
682 | ((sechdrs[i].sh_addr + sechdrs[i].sh_size) > | |
683 | pi->ehdr->e_entry)) { | |
684 | entry_sidx = i; | |
685 | entry -= sechdrs[i].sh_addr; | |
686 | break; | |
687 | } | |
688 | } | |
689 | ||
690 | /* Determine how much memory is needed to load relocatable object. */ | |
691 | buf_align = 1; | |
692 | bss_align = 1; | |
693 | buf_sz = 0; | |
694 | bss_sz = 0; | |
695 | ||
696 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
697 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
698 | continue; | |
699 | ||
700 | align = sechdrs[i].sh_addralign; | |
701 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
702 | if (buf_align < align) | |
703 | buf_align = align; | |
704 | buf_sz = ALIGN(buf_sz, align); | |
705 | buf_sz += sechdrs[i].sh_size; | |
706 | } else { | |
707 | /* bss section */ | |
708 | if (bss_align < align) | |
709 | bss_align = align; | |
710 | bss_sz = ALIGN(bss_sz, align); | |
711 | bss_sz += sechdrs[i].sh_size; | |
712 | } | |
713 | } | |
714 | ||
715 | /* Determine the bss padding required to align bss properly */ | |
716 | bss_pad = 0; | |
717 | if (buf_sz & (bss_align - 1)) | |
718 | bss_pad = bss_align - (buf_sz & (bss_align - 1)); | |
719 | ||
720 | memsz = buf_sz + bss_pad + bss_sz; | |
721 | ||
722 | /* Allocate buffer for purgatory */ | |
723 | purgatory_buf = vzalloc(buf_sz); | |
724 | if (!purgatory_buf) { | |
725 | ret = -ENOMEM; | |
726 | goto out; | |
727 | } | |
728 | ||
729 | if (buf_align < bss_align) | |
730 | buf_align = bss_align; | |
731 | ||
732 | /* Add buffer to segment list */ | |
733 | ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz, | |
734 | buf_align, min, max, top_down, | |
735 | &pi->purgatory_load_addr); | |
736 | if (ret) | |
737 | goto out; | |
738 | ||
739 | /* Load SHF_ALLOC sections */ | |
740 | buf_addr = purgatory_buf; | |
741 | load_addr = curr_load_addr = pi->purgatory_load_addr; | |
742 | bss_addr = load_addr + buf_sz + bss_pad; | |
743 | ||
744 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
745 | if (!(sechdrs[i].sh_flags & SHF_ALLOC)) | |
746 | continue; | |
747 | ||
748 | align = sechdrs[i].sh_addralign; | |
749 | if (sechdrs[i].sh_type != SHT_NOBITS) { | |
750 | curr_load_addr = ALIGN(curr_load_addr, align); | |
751 | offset = curr_load_addr - load_addr; | |
752 | /* We already modifed ->sh_offset to keep src addr */ | |
753 | src = (char *) sechdrs[i].sh_offset; | |
754 | memcpy(buf_addr + offset, src, sechdrs[i].sh_size); | |
755 | ||
756 | /* Store load address and source address of section */ | |
757 | sechdrs[i].sh_addr = curr_load_addr; | |
758 | ||
759 | /* | |
760 | * This section got copied to temporary buffer. Update | |
761 | * ->sh_offset accordingly. | |
762 | */ | |
763 | sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset); | |
764 | ||
765 | /* Advance to the next address */ | |
766 | curr_load_addr += sechdrs[i].sh_size; | |
767 | } else { | |
768 | bss_addr = ALIGN(bss_addr, align); | |
769 | sechdrs[i].sh_addr = bss_addr; | |
770 | bss_addr += sechdrs[i].sh_size; | |
771 | } | |
772 | } | |
773 | ||
774 | /* Update entry point based on load address of text section */ | |
775 | if (entry_sidx >= 0) | |
776 | entry += sechdrs[entry_sidx].sh_addr; | |
777 | ||
778 | /* Make kernel jump to purgatory after shutdown */ | |
779 | image->start = entry; | |
780 | ||
781 | /* Used later to get/set symbol values */ | |
782 | pi->sechdrs = sechdrs; | |
783 | ||
784 | /* | |
785 | * Used later to identify which section is purgatory and skip it | |
786 | * from checksumming. | |
787 | */ | |
788 | pi->purgatory_buf = purgatory_buf; | |
789 | return ret; | |
790 | out: | |
791 | vfree(sechdrs); | |
792 | vfree(purgatory_buf); | |
793 | return ret; | |
794 | } | |
795 | ||
796 | static int kexec_apply_relocations(struct kimage *image) | |
797 | { | |
798 | int i, ret; | |
799 | struct purgatory_info *pi = &image->purgatory_info; | |
800 | Elf_Shdr *sechdrs = pi->sechdrs; | |
801 | ||
802 | /* Apply relocations */ | |
803 | for (i = 0; i < pi->ehdr->e_shnum; i++) { | |
804 | Elf_Shdr *section, *symtab; | |
805 | ||
806 | if (sechdrs[i].sh_type != SHT_RELA && | |
807 | sechdrs[i].sh_type != SHT_REL) | |
808 | continue; | |
809 | ||
810 | /* | |
811 | * For section of type SHT_RELA/SHT_REL, | |
812 | * ->sh_link contains section header index of associated | |
813 | * symbol table. And ->sh_info contains section header | |
814 | * index of section to which relocations apply. | |
815 | */ | |
816 | if (sechdrs[i].sh_info >= pi->ehdr->e_shnum || | |
817 | sechdrs[i].sh_link >= pi->ehdr->e_shnum) | |
818 | return -ENOEXEC; | |
819 | ||
820 | section = &sechdrs[sechdrs[i].sh_info]; | |
821 | symtab = &sechdrs[sechdrs[i].sh_link]; | |
822 | ||
823 | if (!(section->sh_flags & SHF_ALLOC)) | |
824 | continue; | |
825 | ||
826 | /* | |
827 | * symtab->sh_link contain section header index of associated | |
828 | * string table. | |
829 | */ | |
830 | if (symtab->sh_link >= pi->ehdr->e_shnum) | |
831 | /* Invalid section number? */ | |
832 | continue; | |
833 | ||
834 | /* | |
835 | * Respective architecture needs to provide support for applying | |
836 | * relocations of type SHT_RELA/SHT_REL. | |
837 | */ | |
838 | if (sechdrs[i].sh_type == SHT_RELA) | |
839 | ret = arch_kexec_apply_relocations_add(pi->ehdr, | |
840 | sechdrs, i); | |
841 | else if (sechdrs[i].sh_type == SHT_REL) | |
842 | ret = arch_kexec_apply_relocations(pi->ehdr, | |
843 | sechdrs, i); | |
844 | if (ret) | |
845 | return ret; | |
846 | } | |
847 | ||
848 | return 0; | |
849 | } | |
850 | ||
851 | /* Load relocatable purgatory object and relocate it appropriately */ | |
852 | int kexec_load_purgatory(struct kimage *image, unsigned long min, | |
853 | unsigned long max, int top_down, | |
854 | unsigned long *load_addr) | |
855 | { | |
856 | struct purgatory_info *pi = &image->purgatory_info; | |
857 | int ret; | |
858 | ||
859 | if (kexec_purgatory_size <= 0) | |
860 | return -EINVAL; | |
861 | ||
862 | if (kexec_purgatory_size < sizeof(Elf_Ehdr)) | |
863 | return -ENOEXEC; | |
864 | ||
865 | pi->ehdr = (Elf_Ehdr *)kexec_purgatory; | |
866 | ||
867 | if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0 | |
868 | || pi->ehdr->e_type != ET_REL | |
869 | || !elf_check_arch(pi->ehdr) | |
870 | || pi->ehdr->e_shentsize != sizeof(Elf_Shdr)) | |
871 | return -ENOEXEC; | |
872 | ||
873 | if (pi->ehdr->e_shoff >= kexec_purgatory_size | |
874 | || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) > | |
875 | kexec_purgatory_size - pi->ehdr->e_shoff)) | |
876 | return -ENOEXEC; | |
877 | ||
878 | ret = __kexec_load_purgatory(image, min, max, top_down); | |
879 | if (ret) | |
880 | return ret; | |
881 | ||
882 | ret = kexec_apply_relocations(image); | |
883 | if (ret) | |
884 | goto out; | |
885 | ||
886 | *load_addr = pi->purgatory_load_addr; | |
887 | return 0; | |
888 | out: | |
889 | vfree(pi->sechdrs); | |
890 | vfree(pi->purgatory_buf); | |
891 | return ret; | |
892 | } | |
893 | ||
894 | static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, | |
895 | const char *name) | |
896 | { | |
897 | Elf_Sym *syms; | |
898 | Elf_Shdr *sechdrs; | |
899 | Elf_Ehdr *ehdr; | |
900 | int i, k; | |
901 | const char *strtab; | |
902 | ||
903 | if (!pi->sechdrs || !pi->ehdr) | |
904 | return NULL; | |
905 | ||
906 | sechdrs = pi->sechdrs; | |
907 | ehdr = pi->ehdr; | |
908 | ||
909 | for (i = 0; i < ehdr->e_shnum; i++) { | |
910 | if (sechdrs[i].sh_type != SHT_SYMTAB) | |
911 | continue; | |
912 | ||
913 | if (sechdrs[i].sh_link >= ehdr->e_shnum) | |
914 | /* Invalid strtab section number */ | |
915 | continue; | |
916 | strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset; | |
917 | syms = (Elf_Sym *)sechdrs[i].sh_offset; | |
918 | ||
919 | /* Go through symbols for a match */ | |
920 | for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { | |
921 | if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) | |
922 | continue; | |
923 | ||
924 | if (strcmp(strtab + syms[k].st_name, name) != 0) | |
925 | continue; | |
926 | ||
927 | if (syms[k].st_shndx == SHN_UNDEF || | |
928 | syms[k].st_shndx >= ehdr->e_shnum) { | |
929 | pr_debug("Symbol: %s has bad section index %d.\n", | |
930 | name, syms[k].st_shndx); | |
931 | return NULL; | |
932 | } | |
933 | ||
934 | /* Found the symbol we are looking for */ | |
935 | return &syms[k]; | |
936 | } | |
937 | } | |
938 | ||
939 | return NULL; | |
940 | } | |
941 | ||
942 | void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) | |
943 | { | |
944 | struct purgatory_info *pi = &image->purgatory_info; | |
945 | Elf_Sym *sym; | |
946 | Elf_Shdr *sechdr; | |
947 | ||
948 | sym = kexec_purgatory_find_symbol(pi, name); | |
949 | if (!sym) | |
950 | return ERR_PTR(-EINVAL); | |
951 | ||
952 | sechdr = &pi->sechdrs[sym->st_shndx]; | |
953 | ||
954 | /* | |
955 | * Returns the address where symbol will finally be loaded after | |
956 | * kexec_load_segment() | |
957 | */ | |
958 | return (void *)(sechdr->sh_addr + sym->st_value); | |
959 | } | |
960 | ||
961 | /* | |
962 | * Get or set value of a symbol. If "get_value" is true, symbol value is | |
963 | * returned in buf otherwise symbol value is set based on value in buf. | |
964 | */ | |
965 | int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, | |
966 | void *buf, unsigned int size, bool get_value) | |
967 | { | |
968 | Elf_Sym *sym; | |
969 | Elf_Shdr *sechdrs; | |
970 | struct purgatory_info *pi = &image->purgatory_info; | |
971 | char *sym_buf; | |
972 | ||
973 | sym = kexec_purgatory_find_symbol(pi, name); | |
974 | if (!sym) | |
975 | return -EINVAL; | |
976 | ||
977 | if (sym->st_size != size) { | |
978 | pr_err("symbol %s size mismatch: expected %lu actual %u\n", | |
979 | name, (unsigned long)sym->st_size, size); | |
980 | return -EINVAL; | |
981 | } | |
982 | ||
983 | sechdrs = pi->sechdrs; | |
984 | ||
985 | if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) { | |
986 | pr_err("symbol %s is in a bss section. Cannot %s\n", name, | |
987 | get_value ? "get" : "set"); | |
988 | return -EINVAL; | |
989 | } | |
990 | ||
991 | sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset + | |
992 | sym->st_value; | |
993 | ||
994 | if (get_value) | |
995 | memcpy((void *)buf, sym_buf, size); | |
996 | else | |
997 | memcpy((void *)sym_buf, buf, size); | |
998 | ||
999 | return 0; | |
1000 | } |