projects/linux·blob v5.12 · refs

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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kexec: kexec_file_load system call
4 *
5 * Copyright (C) 2014 Red Hat Inc.
6 * Authors:
7 * Vivek Goyal <[email protected]>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/capability.h>
13#include <linux/mm.h>
14#include <linux/file.h>
15#include <linux/slab.h>
16#include <linux/kexec.h>
17#include <linux/memblock.h>
18#include <linux/mutex.h>
19#include <linux/list.h>
20#include <linux/fs.h>
21#include <linux/ima.h>
22#include <crypto/hash.h>
23#include <crypto/sha2.h>
24#include <linux/elf.h>
25#include <linux/elfcore.h>
26#include <linux/kernel.h>
27#include <linux/kernel_read_file.h>
28#include <linux/syscalls.h>
29#include <linux/vmalloc.h>
30#include "kexec_internal.h"
31
32static int kexec_calculate_store_digests(struct kimage *image);
33
34/*
35 * Currently this is the only default function that is exported as some
36 * architectures need it to do additional handlings.
37 * In the future, other default functions may be exported too if required.
38 */
39int kexec_image_probe_default(struct kimage *image, void *buf,
40 unsigned long buf_len)
41{
42 const struct kexec_file_ops * const *fops;
43 int ret = -ENOEXEC;
44
45 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
46 ret = (*fops)->probe(buf, buf_len);
47 if (!ret) {
48 image->fops = *fops;
49 return ret;
50 }
51 }
52
53 return ret;
54}
55
56/* Architectures can provide this probe function */
57int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
58 unsigned long buf_len)
59{
60 return kexec_image_probe_default(image, buf, buf_len);
61}
62
63static void *kexec_image_load_default(struct kimage *image)
64{
65 if (!image->fops || !image->fops->load)
66 return ERR_PTR(-ENOEXEC);
67
68 return image->fops->load(image, image->kernel_buf,
69 image->kernel_buf_len, image->initrd_buf,
70 image->initrd_buf_len, image->cmdline_buf,
71 image->cmdline_buf_len);
72}
73
74void * __weak arch_kexec_kernel_image_load(struct kimage *image)
75{
76 return kexec_image_load_default(image);
77}
78
79int kexec_image_post_load_cleanup_default(struct kimage *image)
80{
81 if (!image->fops || !image->fops->cleanup)
82 return 0;
83
84 return image->fops->cleanup(image->image_loader_data);
85}
86
87int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
88{
89 return kexec_image_post_load_cleanup_default(image);
90}
91
92#ifdef CONFIG_KEXEC_SIG
93static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
94 unsigned long buf_len)
95{
96 if (!image->fops || !image->fops->verify_sig) {
97 pr_debug("kernel loader does not support signature verification.\n");
98 return -EKEYREJECTED;
99 }
100
101 return image->fops->verify_sig(buf, buf_len);
102}
103
104int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
105 unsigned long buf_len)
106{
107 return kexec_image_verify_sig_default(image, buf, buf_len);
108}
109#endif
110
111/*
112 * arch_kexec_apply_relocations_add - apply relocations of type RELA
113 * @pi: Purgatory to be relocated.
114 * @section: Section relocations applying to.
115 * @relsec: Section containing RELAs.
116 * @symtab: Corresponding symtab.
117 *
118 * Return: 0 on success, negative errno on error.
119 */
120int __weak
121arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
122 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
123{
124 pr_err("RELA relocation unsupported.\n");
125 return -ENOEXEC;
126}
127
128/*
129 * arch_kexec_apply_relocations - apply relocations of type REL
130 * @pi: Purgatory to be relocated.
131 * @section: Section relocations applying to.
132 * @relsec: Section containing RELs.
133 * @symtab: Corresponding symtab.
134 *
135 * Return: 0 on success, negative errno on error.
136 */
137int __weak
138arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
139 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
140{
141 pr_err("REL relocation unsupported.\n");
142 return -ENOEXEC;
143}
144
145/*
146 * Free up memory used by kernel, initrd, and command line. This is temporary
147 * memory allocation which is not needed any more after these buffers have
148 * been loaded into separate segments and have been copied elsewhere.
149 */
150void kimage_file_post_load_cleanup(struct kimage *image)
151{
152 struct purgatory_info *pi = &image->purgatory_info;
153
154 vfree(image->kernel_buf);
155 image->kernel_buf = NULL;
156
157 vfree(image->initrd_buf);
158 image->initrd_buf = NULL;
159
160 kfree(image->cmdline_buf);
161 image->cmdline_buf = NULL;
162
163 vfree(pi->purgatory_buf);
164 pi->purgatory_buf = NULL;
165
166 vfree(pi->sechdrs);
167 pi->sechdrs = NULL;
168
169#ifdef CONFIG_IMA_KEXEC
170 vfree(image->ima_buffer);
171 image->ima_buffer = NULL;
172#endif /* CONFIG_IMA_KEXEC */
173
174 /* See if architecture has anything to cleanup post load */
175 arch_kimage_file_post_load_cleanup(image);
176
177 /*
178 * Above call should have called into bootloader to free up
179 * any data stored in kimage->image_loader_data. It should
180 * be ok now to free it up.
181 */
182 kfree(image->image_loader_data);
183 image->image_loader_data = NULL;
184}
185
186#ifdef CONFIG_KEXEC_SIG
187static int
188kimage_validate_signature(struct kimage *image)
189{
190 int ret;
191
192 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
193 image->kernel_buf_len);
194 if (ret) {
195
196 if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
197 pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
198 return ret;
199 }
200
201 /*
202 * If IMA is guaranteed to appraise a signature on the kexec
203 * image, permit it even if the kernel is otherwise locked
204 * down.
205 */
206 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
207 security_locked_down(LOCKDOWN_KEXEC))
208 return -EPERM;
209
210 pr_debug("kernel signature verification failed (%d).\n", ret);
211 }
212
213 return 0;
214}
215#endif
216
217/*
218 * In file mode list of segments is prepared by kernel. Copy relevant
219 * data from user space, do error checking, prepare segment list
220 */
221static int
222kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
223 const char __user *cmdline_ptr,
224 unsigned long cmdline_len, unsigned flags)
225{
226 int ret;
227 void *ldata;
228
229 ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
230 INT_MAX, NULL, READING_KEXEC_IMAGE);
231 if (ret < 0)
232 return ret;
233 image->kernel_buf_len = ret;
234
235 /* Call arch image probe handlers */
236 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
237 image->kernel_buf_len);
238 if (ret)
239 goto out;
240
241#ifdef CONFIG_KEXEC_SIG
242 ret = kimage_validate_signature(image);
243
244 if (ret)
245 goto out;
246#endif
247 /* It is possible that there no initramfs is being loaded */
248 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
249 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
250 INT_MAX, NULL,
251 READING_KEXEC_INITRAMFS);
252 if (ret < 0)
253 goto out;
254 image->initrd_buf_len = ret;
255 ret = 0;
256 }
257
258 if (cmdline_len) {
259 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
260 if (IS_ERR(image->cmdline_buf)) {
261 ret = PTR_ERR(image->cmdline_buf);
262 image->cmdline_buf = NULL;
263 goto out;
264 }
265
266 image->cmdline_buf_len = cmdline_len;
267
268 /* command line should be a string with last byte null */
269 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
270 ret = -EINVAL;
271 goto out;
272 }
273
274 ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
275 image->cmdline_buf_len - 1);
276 }
277
278 /* IMA needs to pass the measurement list to the next kernel. */
279 ima_add_kexec_buffer(image);
280
281 /* Call arch image load handlers */
282 ldata = arch_kexec_kernel_image_load(image);
283
284 if (IS_ERR(ldata)) {
285 ret = PTR_ERR(ldata);
286 goto out;
287 }
288
289 image->image_loader_data = ldata;
290out:
291 /* In case of error, free up all allocated memory in this function */
292 if (ret)
293 kimage_file_post_load_cleanup(image);
294 return ret;
295}
296
297static int
298kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
299 int initrd_fd, const char __user *cmdline_ptr,
300 unsigned long cmdline_len, unsigned long flags)
301{
302 int ret;
303 struct kimage *image;
304 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
305
306 image = do_kimage_alloc_init();
307 if (!image)
308 return -ENOMEM;
309
310 image->file_mode = 1;
311
312 if (kexec_on_panic) {
313 /* Enable special crash kernel control page alloc policy. */
314 image->control_page = crashk_res.start;
315 image->type = KEXEC_TYPE_CRASH;
316 }
317
318 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
319 cmdline_ptr, cmdline_len, flags);
320 if (ret)
321 goto out_free_image;
322
323 ret = sanity_check_segment_list(image);
324 if (ret)
325 goto out_free_post_load_bufs;
326
327 ret = -ENOMEM;
328 image->control_code_page = kimage_alloc_control_pages(image,
329 get_order(KEXEC_CONTROL_PAGE_SIZE));
330 if (!image->control_code_page) {
331 pr_err("Could not allocate control_code_buffer\n");
332 goto out_free_post_load_bufs;
333 }
334
335 if (!kexec_on_panic) {
336 image->swap_page = kimage_alloc_control_pages(image, 0);
337 if (!image->swap_page) {
338 pr_err("Could not allocate swap buffer\n");
339 goto out_free_control_pages;
340 }
341 }
342
343 *rimage = image;
344 return 0;
345out_free_control_pages:
346 kimage_free_page_list(&image->control_pages);
347out_free_post_load_bufs:
348 kimage_file_post_load_cleanup(image);
349out_free_image:
350 kfree(image);
351 return ret;
352}
353
354SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
355 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
356 unsigned long, flags)
357{
358 int ret = 0, i;
359 struct kimage **dest_image, *image;
360
361 /* We only trust the superuser with rebooting the system. */
362 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
363 return -EPERM;
364
365 /* Make sure we have a legal set of flags */
366 if (flags != (flags & KEXEC_FILE_FLAGS))
367 return -EINVAL;
368
369 image = NULL;
370
371 if (!mutex_trylock(&kexec_mutex))
372 return -EBUSY;
373
374 dest_image = &kexec_image;
375 if (flags & KEXEC_FILE_ON_CRASH) {
376 dest_image = &kexec_crash_image;
377 if (kexec_crash_image)
378 arch_kexec_unprotect_crashkres();
379 }
380
381 if (flags & KEXEC_FILE_UNLOAD)
382 goto exchange;
383
384 /*
385 * In case of crash, new kernel gets loaded in reserved region. It is
386 * same memory where old crash kernel might be loaded. Free any
387 * current crash dump kernel before we corrupt it.
388 */
389 if (flags & KEXEC_FILE_ON_CRASH)
390 kimage_free(xchg(&kexec_crash_image, NULL));
391
392 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
393 cmdline_len, flags);
394 if (ret)
395 goto out;
396
397 ret = machine_kexec_prepare(image);
398 if (ret)
399 goto out;
400
401 /*
402 * Some architecture(like S390) may touch the crash memory before
403 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
404 */
405 ret = kimage_crash_copy_vmcoreinfo(image);
406 if (ret)
407 goto out;
408
409 ret = kexec_calculate_store_digests(image);
410 if (ret)
411 goto out;
412
413 for (i = 0; i < image->nr_segments; i++) {
414 struct kexec_segment *ksegment;
415
416 ksegment = &image->segment[i];
417 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
418 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
419 ksegment->memsz);
420
421 ret = kimage_load_segment(image, &image->segment[i]);
422 if (ret)
423 goto out;
424 }
425
426 kimage_terminate(image);
427
428 ret = machine_kexec_post_load(image);
429 if (ret)
430 goto out;
431
432 /*
433 * Free up any temporary buffers allocated which are not needed
434 * after image has been loaded
435 */
436 kimage_file_post_load_cleanup(image);
437exchange:
438 image = xchg(dest_image, image);
439out:
440 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
441 arch_kexec_protect_crashkres();
442
443 mutex_unlock(&kexec_mutex);
444 kimage_free(image);
445 return ret;
446}
447
448static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
449 struct kexec_buf *kbuf)
450{
451 struct kimage *image = kbuf->image;
452 unsigned long temp_start, temp_end;
453
454 temp_end = min(end, kbuf->buf_max);
455 temp_start = temp_end - kbuf->memsz;
456
457 do {
458 /* align down start */
459 temp_start = temp_start & (~(kbuf->buf_align - 1));
460
461 if (temp_start < start || temp_start < kbuf->buf_min)
462 return 0;
463
464 temp_end = temp_start + kbuf->memsz - 1;
465
466 /*
467 * Make sure this does not conflict with any of existing
468 * segments
469 */
470 if (kimage_is_destination_range(image, temp_start, temp_end)) {
471 temp_start = temp_start - PAGE_SIZE;
472 continue;
473 }
474
475 /* We found a suitable memory range */
476 break;
477 } while (1);
478
479 /* If we are here, we found a suitable memory range */
480 kbuf->mem = temp_start;
481
482 /* Success, stop navigating through remaining System RAM ranges */
483 return 1;
484}
485
486static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
487 struct kexec_buf *kbuf)
488{
489 struct kimage *image = kbuf->image;
490 unsigned long temp_start, temp_end;
491
492 temp_start = max(start, kbuf->buf_min);
493
494 do {
495 temp_start = ALIGN(temp_start, kbuf->buf_align);
496 temp_end = temp_start + kbuf->memsz - 1;
497
498 if (temp_end > end || temp_end > kbuf->buf_max)
499 return 0;
500 /*
501 * Make sure this does not conflict with any of existing
502 * segments
503 */
504 if (kimage_is_destination_range(image, temp_start, temp_end)) {
505 temp_start = temp_start + PAGE_SIZE;
506 continue;
507 }
508
509 /* We found a suitable memory range */
510 break;
511 } while (1);
512
513 /* If we are here, we found a suitable memory range */
514 kbuf->mem = temp_start;
515
516 /* Success, stop navigating through remaining System RAM ranges */
517 return 1;
518}
519
520static int locate_mem_hole_callback(struct resource *res, void *arg)
521{
522 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
523 u64 start = res->start, end = res->end;
524 unsigned long sz = end - start + 1;
525
526 /* Returning 0 will take to next memory range */
527
528 /* Don't use memory that will be detected and handled by a driver. */
529 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
530 return 0;
531
532 if (sz < kbuf->memsz)
533 return 0;
534
535 if (end < kbuf->buf_min || start > kbuf->buf_max)
536 return 0;
537
538 /*
539 * Allocate memory top down with-in ram range. Otherwise bottom up
540 * allocation.
541 */
542 if (kbuf->top_down)
543 return locate_mem_hole_top_down(start, end, kbuf);
544 return locate_mem_hole_bottom_up(start, end, kbuf);
545}
546
547#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
548static int kexec_walk_memblock(struct kexec_buf *kbuf,
549 int (*func)(struct resource *, void *))
550{
551 int ret = 0;
552 u64 i;
553 phys_addr_t mstart, mend;
554 struct resource res = { };
555
556 if (kbuf->image->type == KEXEC_TYPE_CRASH)
557 return func(&crashk_res, kbuf);
558
559 if (kbuf->top_down) {
560 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
561 &mstart, &mend, NULL) {
562 /*
563 * In memblock, end points to the first byte after the
564 * range while in kexec, end points to the last byte
565 * in the range.
566 */
567 res.start = mstart;
568 res.end = mend - 1;
569 ret = func(&res, kbuf);
570 if (ret)
571 break;
572 }
573 } else {
574 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
575 &mstart, &mend, NULL) {
576 /*
577 * In memblock, end points to the first byte after the
578 * range while in kexec, end points to the last byte
579 * in the range.
580 */
581 res.start = mstart;
582 res.end = mend - 1;
583 ret = func(&res, kbuf);
584 if (ret)
585 break;
586 }
587 }
588
589 return ret;
590}
591#else
592static int kexec_walk_memblock(struct kexec_buf *kbuf,
593 int (*func)(struct resource *, void *))
594{
595 return 0;
596}
597#endif
598
599/**
600 * kexec_walk_resources - call func(data) on free memory regions
601 * @kbuf: Context info for the search. Also passed to @func.
602 * @func: Function to call for each memory region.
603 *
604 * Return: The memory walk will stop when func returns a non-zero value
605 * and that value will be returned. If all free regions are visited without
606 * func returning non-zero, then zero will be returned.
607 */
608static int kexec_walk_resources(struct kexec_buf *kbuf,
609 int (*func)(struct resource *, void *))
610{
611 if (kbuf->image->type == KEXEC_TYPE_CRASH)
612 return walk_iomem_res_desc(crashk_res.desc,
613 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
614 crashk_res.start, crashk_res.end,
615 kbuf, func);
616 else
617 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
618}
619
620/**
621 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
622 * @kbuf: Parameters for the memory search.
623 *
624 * On success, kbuf->mem will have the start address of the memory region found.
625 *
626 * Return: 0 on success, negative errno on error.
627 */
628int kexec_locate_mem_hole(struct kexec_buf *kbuf)
629{
630 int ret;
631
632 /* Arch knows where to place */
633 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
634 return 0;
635
636 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
637 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
638 else
639 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
640
641 return ret == 1 ? 0 : -EADDRNOTAVAIL;
642}
643
644/**
645 * arch_kexec_locate_mem_hole - Find free memory to place the segments.
646 * @kbuf: Parameters for the memory search.
647 *
648 * On success, kbuf->mem will have the start address of the memory region found.
649 *
650 * Return: 0 on success, negative errno on error.
651 */
652int __weak arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
653{
654 return kexec_locate_mem_hole(kbuf);
655}
656
657/**
658 * kexec_add_buffer - place a buffer in a kexec segment
659 * @kbuf: Buffer contents and memory parameters.
660 *
661 * This function assumes that kexec_mutex is held.
662 * On successful return, @kbuf->mem will have the physical address of
663 * the buffer in memory.
664 *
665 * Return: 0 on success, negative errno on error.
666 */
667int kexec_add_buffer(struct kexec_buf *kbuf)
668{
669 struct kexec_segment *ksegment;
670 int ret;
671
672 /* Currently adding segment this way is allowed only in file mode */
673 if (!kbuf->image->file_mode)
674 return -EINVAL;
675
676 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
677 return -EINVAL;
678
679 /*
680 * Make sure we are not trying to add buffer after allocating
681 * control pages. All segments need to be placed first before
682 * any control pages are allocated. As control page allocation
683 * logic goes through list of segments to make sure there are
684 * no destination overlaps.
685 */
686 if (!list_empty(&kbuf->image->control_pages)) {
687 WARN_ON(1);
688 return -EINVAL;
689 }
690
691 /* Ensure minimum alignment needed for segments. */
692 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
693 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
694
695 /* Walk the RAM ranges and allocate a suitable range for the buffer */
696 ret = arch_kexec_locate_mem_hole(kbuf);
697 if (ret)
698 return ret;
699
700 /* Found a suitable memory range */
701 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
702 ksegment->kbuf = kbuf->buffer;
703 ksegment->bufsz = kbuf->bufsz;
704 ksegment->mem = kbuf->mem;
705 ksegment->memsz = kbuf->memsz;
706 kbuf->image->nr_segments++;
707 return 0;
708}
709
710/* Calculate and store the digest of segments */
711static int kexec_calculate_store_digests(struct kimage *image)
712{
713 struct crypto_shash *tfm;
714 struct shash_desc *desc;
715 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
716 size_t desc_size, nullsz;
717 char *digest;
718 void *zero_buf;
719 struct kexec_sha_region *sha_regions;
720 struct purgatory_info *pi = &image->purgatory_info;
721
722 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
723 return 0;
724
725 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
726 zero_buf_sz = PAGE_SIZE;
727
728 tfm = crypto_alloc_shash("sha256", 0, 0);
729 if (IS_ERR(tfm)) {
730 ret = PTR_ERR(tfm);
731 goto out;
732 }
733
734 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
735 desc = kzalloc(desc_size, GFP_KERNEL);
736 if (!desc) {
737 ret = -ENOMEM;
738 goto out_free_tfm;
739 }
740
741 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
742 sha_regions = vzalloc(sha_region_sz);
743 if (!sha_regions)
744 goto out_free_desc;
745
746 desc->tfm = tfm;
747
748 ret = crypto_shash_init(desc);
749 if (ret < 0)
750 goto out_free_sha_regions;
751
752 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
753 if (!digest) {
754 ret = -ENOMEM;
755 goto out_free_sha_regions;
756 }
757
758 for (j = i = 0; i < image->nr_segments; i++) {
759 struct kexec_segment *ksegment;
760
761 ksegment = &image->segment[i];
762 /*
763 * Skip purgatory as it will be modified once we put digest
764 * info in purgatory.
765 */
766 if (ksegment->kbuf == pi->purgatory_buf)
767 continue;
768
769 ret = crypto_shash_update(desc, ksegment->kbuf,
770 ksegment->bufsz);
771 if (ret)
772 break;
773
774 /*
775 * Assume rest of the buffer is filled with zero and
776 * update digest accordingly.
777 */
778 nullsz = ksegment->memsz - ksegment->bufsz;
779 while (nullsz) {
780 unsigned long bytes = nullsz;
781
782 if (bytes > zero_buf_sz)
783 bytes = zero_buf_sz;
784 ret = crypto_shash_update(desc, zero_buf, bytes);
785 if (ret)
786 break;
787 nullsz -= bytes;
788 }
789
790 if (ret)
791 break;
792
793 sha_regions[j].start = ksegment->mem;
794 sha_regions[j].len = ksegment->memsz;
795 j++;
796 }
797
798 if (!ret) {
799 ret = crypto_shash_final(desc, digest);
800 if (ret)
801 goto out_free_digest;
802 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
803 sha_regions, sha_region_sz, 0);
804 if (ret)
805 goto out_free_digest;
806
807 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
808 digest, SHA256_DIGEST_SIZE, 0);
809 if (ret)
810 goto out_free_digest;
811 }
812
813out_free_digest:
814 kfree(digest);
815out_free_sha_regions:
816 vfree(sha_regions);
817out_free_desc:
818 kfree(desc);
819out_free_tfm:
820 kfree(tfm);
821out:
822 return ret;
823}
824
825#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
826/*
827 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
828 * @pi: Purgatory to be loaded.
829 * @kbuf: Buffer to setup.
830 *
831 * Allocates the memory needed for the buffer. Caller is responsible to free
832 * the memory after use.
833 *
834 * Return: 0 on success, negative errno on error.
835 */
836static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
837 struct kexec_buf *kbuf)
838{
839 const Elf_Shdr *sechdrs;
840 unsigned long bss_align;
841 unsigned long bss_sz;
842 unsigned long align;
843 int i, ret;
844
845 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
846 kbuf->buf_align = bss_align = 1;
847 kbuf->bufsz = bss_sz = 0;
848
849 for (i = 0; i < pi->ehdr->e_shnum; i++) {
850 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
851 continue;
852
853 align = sechdrs[i].sh_addralign;
854 if (sechdrs[i].sh_type != SHT_NOBITS) {
855 if (kbuf->buf_align < align)
856 kbuf->buf_align = align;
857 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
858 kbuf->bufsz += sechdrs[i].sh_size;
859 } else {
860 if (bss_align < align)
861 bss_align = align;
862 bss_sz = ALIGN(bss_sz, align);
863 bss_sz += sechdrs[i].sh_size;
864 }
865 }
866 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
867 kbuf->memsz = kbuf->bufsz + bss_sz;
868 if (kbuf->buf_align < bss_align)
869 kbuf->buf_align = bss_align;
870
871 kbuf->buffer = vzalloc(kbuf->bufsz);
872 if (!kbuf->buffer)
873 return -ENOMEM;
874 pi->purgatory_buf = kbuf->buffer;
875
876 ret = kexec_add_buffer(kbuf);
877 if (ret)
878 goto out;
879
880 return 0;
881out:
882 vfree(pi->purgatory_buf);
883 pi->purgatory_buf = NULL;
884 return ret;
885}
886
887/*
888 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
889 * @pi: Purgatory to be loaded.
890 * @kbuf: Buffer prepared to store purgatory.
891 *
892 * Allocates the memory needed for the buffer. Caller is responsible to free
893 * the memory after use.
894 *
895 * Return: 0 on success, negative errno on error.
896 */
897static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
898 struct kexec_buf *kbuf)
899{
900 unsigned long bss_addr;
901 unsigned long offset;
902 Elf_Shdr *sechdrs;
903 int i;
904
905 /*
906 * The section headers in kexec_purgatory are read-only. In order to
907 * have them modifiable make a temporary copy.
908 */
909 sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
910 if (!sechdrs)
911 return -ENOMEM;
912 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
913 pi->ehdr->e_shnum * sizeof(Elf_Shdr));
914 pi->sechdrs = sechdrs;
915
916 offset = 0;
917 bss_addr = kbuf->mem + kbuf->bufsz;
918 kbuf->image->start = pi->ehdr->e_entry;
919
920 for (i = 0; i < pi->ehdr->e_shnum; i++) {
921 unsigned long align;
922 void *src, *dst;
923
924 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
925 continue;
926
927 align = sechdrs[i].sh_addralign;
928 if (sechdrs[i].sh_type == SHT_NOBITS) {
929 bss_addr = ALIGN(bss_addr, align);
930 sechdrs[i].sh_addr = bss_addr;
931 bss_addr += sechdrs[i].sh_size;
932 continue;
933 }
934
935 offset = ALIGN(offset, align);
936 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
937 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
938 pi->ehdr->e_entry < (sechdrs[i].sh_addr
939 + sechdrs[i].sh_size)) {
940 kbuf->image->start -= sechdrs[i].sh_addr;
941 kbuf->image->start += kbuf->mem + offset;
942 }
943
944 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
945 dst = pi->purgatory_buf + offset;
946 memcpy(dst, src, sechdrs[i].sh_size);
947
948 sechdrs[i].sh_addr = kbuf->mem + offset;
949 sechdrs[i].sh_offset = offset;
950 offset += sechdrs[i].sh_size;
951 }
952
953 return 0;
954}
955
956static int kexec_apply_relocations(struct kimage *image)
957{
958 int i, ret;
959 struct purgatory_info *pi = &image->purgatory_info;
960 const Elf_Shdr *sechdrs;
961
962 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
963
964 for (i = 0; i < pi->ehdr->e_shnum; i++) {
965 const Elf_Shdr *relsec;
966 const Elf_Shdr *symtab;
967 Elf_Shdr *section;
968
969 relsec = sechdrs + i;
970
971 if (relsec->sh_type != SHT_RELA &&
972 relsec->sh_type != SHT_REL)
973 continue;
974
975 /*
976 * For section of type SHT_RELA/SHT_REL,
977 * ->sh_link contains section header index of associated
978 * symbol table. And ->sh_info contains section header
979 * index of section to which relocations apply.
980 */
981 if (relsec->sh_info >= pi->ehdr->e_shnum ||
982 relsec->sh_link >= pi->ehdr->e_shnum)
983 return -ENOEXEC;
984
985 section = pi->sechdrs + relsec->sh_info;
986 symtab = sechdrs + relsec->sh_link;
987
988 if (!(section->sh_flags & SHF_ALLOC))
989 continue;
990
991 /*
992 * symtab->sh_link contain section header index of associated
993 * string table.
994 */
995 if (symtab->sh_link >= pi->ehdr->e_shnum)
996 /* Invalid section number? */
997 continue;
998
999 /*
1000 * Respective architecture needs to provide support for applying
1001 * relocations of type SHT_RELA/SHT_REL.
1002 */
1003 if (relsec->sh_type == SHT_RELA)
1004 ret = arch_kexec_apply_relocations_add(pi, section,
1005 relsec, symtab);
1006 else if (relsec->sh_type == SHT_REL)
1007 ret = arch_kexec_apply_relocations(pi, section,
1008 relsec, symtab);
1009 if (ret)
1010 return ret;
1011 }
1012
1013 return 0;
1014}
1015
1016/*
1017 * kexec_load_purgatory - Load and relocate the purgatory object.
1018 * @image: Image to add the purgatory to.
1019 * @kbuf: Memory parameters to use.
1020 *
1021 * Allocates the memory needed for image->purgatory_info.sechdrs and
1022 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1023 * to free the memory after use.
1024 *
1025 * Return: 0 on success, negative errno on error.
1026 */
1027int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1028{
1029 struct purgatory_info *pi = &image->purgatory_info;
1030 int ret;
1031
1032 if (kexec_purgatory_size <= 0)
1033 return -EINVAL;
1034
1035 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1036
1037 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1038 if (ret)
1039 return ret;
1040
1041 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1042 if (ret)
1043 goto out_free_kbuf;
1044
1045 ret = kexec_apply_relocations(image);
1046 if (ret)
1047 goto out;
1048
1049 return 0;
1050out:
1051 vfree(pi->sechdrs);
1052 pi->sechdrs = NULL;
1053out_free_kbuf:
1054 vfree(pi->purgatory_buf);
1055 pi->purgatory_buf = NULL;
1056 return ret;
1057}
1058
1059/*
1060 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1061 * @pi: Purgatory to search in.
1062 * @name: Name of the symbol.
1063 *
1064 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1065 */
1066static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1067 const char *name)
1068{
1069 const Elf_Shdr *sechdrs;
1070 const Elf_Ehdr *ehdr;
1071 const Elf_Sym *syms;
1072 const char *strtab;
1073 int i, k;
1074
1075 if (!pi->ehdr)
1076 return NULL;
1077
1078 ehdr = pi->ehdr;
1079 sechdrs = (void *)ehdr + ehdr->e_shoff;
1080
1081 for (i = 0; i < ehdr->e_shnum; i++) {
1082 if (sechdrs[i].sh_type != SHT_SYMTAB)
1083 continue;
1084
1085 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1086 /* Invalid strtab section number */
1087 continue;
1088 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1089 syms = (void *)ehdr + sechdrs[i].sh_offset;
1090
1091 /* Go through symbols for a match */
1092 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1093 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1094 continue;
1095
1096 if (strcmp(strtab + syms[k].st_name, name) != 0)
1097 continue;
1098
1099 if (syms[k].st_shndx == SHN_UNDEF ||
1100 syms[k].st_shndx >= ehdr->e_shnum) {
1101 pr_debug("Symbol: %s has bad section index %d.\n",
1102 name, syms[k].st_shndx);
1103 return NULL;
1104 }
1105
1106 /* Found the symbol we are looking for */
1107 return &syms[k];
1108 }
1109 }
1110
1111 return NULL;
1112}
1113
1114void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1115{
1116 struct purgatory_info *pi = &image->purgatory_info;
1117 const Elf_Sym *sym;
1118 Elf_Shdr *sechdr;
1119
1120 sym = kexec_purgatory_find_symbol(pi, name);
1121 if (!sym)
1122 return ERR_PTR(-EINVAL);
1123
1124 sechdr = &pi->sechdrs[sym->st_shndx];
1125
1126 /*
1127 * Returns the address where symbol will finally be loaded after
1128 * kexec_load_segment()
1129 */
1130 return (void *)(sechdr->sh_addr + sym->st_value);
1131}
1132
1133/*
1134 * Get or set value of a symbol. If "get_value" is true, symbol value is
1135 * returned in buf otherwise symbol value is set based on value in buf.
1136 */
1137int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1138 void *buf, unsigned int size, bool get_value)
1139{
1140 struct purgatory_info *pi = &image->purgatory_info;
1141 const Elf_Sym *sym;
1142 Elf_Shdr *sec;
1143 char *sym_buf;
1144
1145 sym = kexec_purgatory_find_symbol(pi, name);
1146 if (!sym)
1147 return -EINVAL;
1148
1149 if (sym->st_size != size) {
1150 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1151 name, (unsigned long)sym->st_size, size);
1152 return -EINVAL;
1153 }
1154
1155 sec = pi->sechdrs + sym->st_shndx;
1156
1157 if (sec->sh_type == SHT_NOBITS) {
1158 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1159 get_value ? "get" : "set");
1160 return -EINVAL;
1161 }
1162
1163 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1164
1165 if (get_value)
1166 memcpy((void *)buf, sym_buf, size);
1167 else
1168 memcpy((void *)sym_buf, buf, size);
1169
1170 return 0;
1171}
1172#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1173
1174int crash_exclude_mem_range(struct crash_mem *mem,
1175 unsigned long long mstart, unsigned long long mend)
1176{
1177 int i, j;
1178 unsigned long long start, end, p_start, p_end;
1179 struct crash_mem_range temp_range = {0, 0};
1180
1181 for (i = 0; i < mem->nr_ranges; i++) {
1182 start = mem->ranges[i].start;
1183 end = mem->ranges[i].end;
1184 p_start = mstart;
1185 p_end = mend;
1186
1187 if (mstart > end || mend < start)
1188 continue;
1189
1190 /* Truncate any area outside of range */
1191 if (mstart < start)
1192 p_start = start;
1193 if (mend > end)
1194 p_end = end;
1195
1196 /* Found completely overlapping range */
1197 if (p_start == start && p_end == end) {
1198 mem->ranges[i].start = 0;
1199 mem->ranges[i].end = 0;
1200 if (i < mem->nr_ranges - 1) {
1201 /* Shift rest of the ranges to left */
1202 for (j = i; j < mem->nr_ranges - 1; j++) {
1203 mem->ranges[j].start =
1204 mem->ranges[j+1].start;
1205 mem->ranges[j].end =
1206 mem->ranges[j+1].end;
1207 }
1208
1209 /*
1210 * Continue to check if there are another overlapping ranges
1211 * from the current position because of shifting the above
1212 * mem ranges.
1213 */
1214 i--;
1215 mem->nr_ranges--;
1216 continue;
1217 }
1218 mem->nr_ranges--;
1219 return 0;
1220 }
1221
1222 if (p_start > start && p_end < end) {
1223 /* Split original range */
1224 mem->ranges[i].end = p_start - 1;
1225 temp_range.start = p_end + 1;
1226 temp_range.end = end;
1227 } else if (p_start != start)
1228 mem->ranges[i].end = p_start - 1;
1229 else
1230 mem->ranges[i].start = p_end + 1;
1231 break;
1232 }
1233
1234 /* If a split happened, add the split to array */
1235 if (!temp_range.end)
1236 return 0;
1237
1238 /* Split happened */
1239 if (i == mem->max_nr_ranges - 1)
1240 return -ENOMEM;
1241
1242 /* Location where new range should go */
1243 j = i + 1;
1244 if (j < mem->nr_ranges) {
1245 /* Move over all ranges one slot towards the end */
1246 for (i = mem->nr_ranges - 1; i >= j; i--)
1247 mem->ranges[i + 1] = mem->ranges[i];
1248 }
1249
1250 mem->ranges[j].start = temp_range.start;
1251 mem->ranges[j].end = temp_range.end;
1252 mem->nr_ranges++;
1253 return 0;
1254}
1255
1256int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1257 void **addr, unsigned long *sz)
1258{
1259 Elf64_Ehdr *ehdr;
1260 Elf64_Phdr *phdr;
1261 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1262 unsigned char *buf;
1263 unsigned int cpu, i;
1264 unsigned long long notes_addr;
1265 unsigned long mstart, mend;
1266
1267 /* extra phdr for vmcoreinfo ELF note */
1268 nr_phdr = nr_cpus + 1;
1269 nr_phdr += mem->nr_ranges;
1270
1271 /*
1272 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1273 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1274 * I think this is required by tools like gdb. So same physical
1275 * memory will be mapped in two ELF headers. One will contain kernel
1276 * text virtual addresses and other will have __va(physical) addresses.
1277 */
1278
1279 nr_phdr++;
1280 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1281 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1282
1283 buf = vzalloc(elf_sz);
1284 if (!buf)
1285 return -ENOMEM;
1286
1287 ehdr = (Elf64_Ehdr *)buf;
1288 phdr = (Elf64_Phdr *)(ehdr + 1);
1289 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1290 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1291 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1292 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1293 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1294 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1295 ehdr->e_type = ET_CORE;
1296 ehdr->e_machine = ELF_ARCH;
1297 ehdr->e_version = EV_CURRENT;
1298 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1299 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1300 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1301
1302 /* Prepare one phdr of type PT_NOTE for each present CPU */
1303 for_each_present_cpu(cpu) {
1304 phdr->p_type = PT_NOTE;
1305 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1306 phdr->p_offset = phdr->p_paddr = notes_addr;
1307 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1308 (ehdr->e_phnum)++;
1309 phdr++;
1310 }
1311
1312 /* Prepare one PT_NOTE header for vmcoreinfo */
1313 phdr->p_type = PT_NOTE;
1314 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1315 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1316 (ehdr->e_phnum)++;
1317 phdr++;
1318
1319 /* Prepare PT_LOAD type program header for kernel text region */
1320 if (kernel_map) {
1321 phdr->p_type = PT_LOAD;
1322 phdr->p_flags = PF_R|PF_W|PF_X;
1323 phdr->p_vaddr = (unsigned long) _text;
1324 phdr->p_filesz = phdr->p_memsz = _end - _text;
1325 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1326 ehdr->e_phnum++;
1327 phdr++;
1328 }
1329
1330 /* Go through all the ranges in mem->ranges[] and prepare phdr */
1331 for (i = 0; i < mem->nr_ranges; i++) {
1332 mstart = mem->ranges[i].start;
1333 mend = mem->ranges[i].end;
1334
1335 phdr->p_type = PT_LOAD;
1336 phdr->p_flags = PF_R|PF_W|PF_X;
1337 phdr->p_offset = mstart;
1338
1339 phdr->p_paddr = mstart;
1340 phdr->p_vaddr = (unsigned long) __va(mstart);
1341 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1342 phdr->p_align = 0;
1343 ehdr->e_phnum++;
1344 pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
1345 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1346 ehdr->e_phnum, phdr->p_offset);
1347 phdr++;
1348 }
1349
1350 *addr = buf;
1351 *sz = elf_sz;
1352 return 0;
1353}