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1/*
2 * kexec: kexec_file_load system call
3 *
4 * Copyright (C) 2014 Red Hat Inc.
5 * Authors:
6 * Vivek Goyal <vgoyal@redhat.com>
7 *
8 * This source code is licensed under the GNU General Public License,
9 * Version 2. See the file COPYING for more details.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/capability.h>
15#include <linux/mm.h>
16#include <linux/file.h>
17#include <linux/slab.h>
18#include <linux/kexec.h>
19#include <linux/mutex.h>
20#include <linux/list.h>
21#include <linux/fs.h>
22#include <linux/ima.h>
23#include <crypto/hash.h>
24#include <crypto/sha.h>
25#include <linux/elf.h>
26#include <linux/elfcore.h>
27#include <linux/kernel.h>
28#include <linux/kexec.h>
29#include <linux/slab.h>
30#include <linux/syscalls.h>
31#include <linux/vmalloc.h>
32#include "kexec_internal.h"
33
34static int kexec_calculate_store_digests(struct kimage *image);
35
36/*
37 * Currently this is the only default function that is exported as some
38 * architectures need it to do additional handlings.
39 * In the future, other default functions may be exported too if required.
40 */
41int kexec_image_probe_default(struct kimage *image, void *buf,
42 unsigned long buf_len)
43{
44 const struct kexec_file_ops * const *fops;
45 int ret = -ENOEXEC;
46
47 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
48 ret = (*fops)->probe(buf, buf_len);
49 if (!ret) {
50 image->fops = *fops;
51 return ret;
52 }
53 }
54
55 return ret;
56}
57
58/* Architectures can provide this probe function */
59int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
60 unsigned long buf_len)
61{
62 return kexec_image_probe_default(image, buf, buf_len);
63}
64
65static void *kexec_image_load_default(struct kimage *image)
66{
67 if (!image->fops || !image->fops->load)
68 return ERR_PTR(-ENOEXEC);
69
70 return image->fops->load(image, image->kernel_buf,
71 image->kernel_buf_len, image->initrd_buf,
72 image->initrd_buf_len, image->cmdline_buf,
73 image->cmdline_buf_len);
74}
75
76void * __weak arch_kexec_kernel_image_load(struct kimage *image)
77{
78 return kexec_image_load_default(image);
79}
80
81static int kexec_image_post_load_cleanup_default(struct kimage *image)
82{
83 if (!image->fops || !image->fops->cleanup)
84 return 0;
85
86 return image->fops->cleanup(image->image_loader_data);
87}
88
89int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
90{
91 return kexec_image_post_load_cleanup_default(image);
92}
93
94#ifdef CONFIG_KEXEC_VERIFY_SIG
95static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
96 unsigned long buf_len)
97{
98 if (!image->fops || !image->fops->verify_sig) {
99 pr_debug("kernel loader does not support signature verification.\n");
100 return -EKEYREJECTED;
101 }
102
103 return image->fops->verify_sig(buf, buf_len);
104}
105
106int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
107 unsigned long buf_len)
108{
109 return kexec_image_verify_sig_default(image, buf, buf_len);
110}
111#endif
112
113/*
114 * arch_kexec_apply_relocations_add - apply relocations of type RELA
115 * @pi: Purgatory to be relocated.
116 * @section: Section relocations applying to.
117 * @relsec: Section containing RELAs.
118 * @symtab: Corresponding symtab.
119 *
120 * Return: 0 on success, negative errno on error.
121 */
122int __weak
123arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
124 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
125{
126 pr_err("RELA relocation unsupported.\n");
127 return -ENOEXEC;
128}
129
130/*
131 * arch_kexec_apply_relocations - apply relocations of type REL
132 * @pi: Purgatory to be relocated.
133 * @section: Section relocations applying to.
134 * @relsec: Section containing RELs.
135 * @symtab: Corresponding symtab.
136 *
137 * Return: 0 on success, negative errno on error.
138 */
139int __weak
140arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
141 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
142{
143 pr_err("REL relocation unsupported.\n");
144 return -ENOEXEC;
145}
146
147/*
148 * Free up memory used by kernel, initrd, and command line. This is temporary
149 * memory allocation which is not needed any more after these buffers have
150 * been loaded into separate segments and have been copied elsewhere.
151 */
152void kimage_file_post_load_cleanup(struct kimage *image)
153{
154 struct purgatory_info *pi = &image->purgatory_info;
155
156 vfree(image->kernel_buf);
157 image->kernel_buf = NULL;
158
159 vfree(image->initrd_buf);
160 image->initrd_buf = NULL;
161
162 kfree(image->cmdline_buf);
163 image->cmdline_buf = NULL;
164
165 vfree(pi->purgatory_buf);
166 pi->purgatory_buf = NULL;
167
168 vfree(pi->sechdrs);
169 pi->sechdrs = NULL;
170
171 /* See if architecture has anything to cleanup post load */
172 arch_kimage_file_post_load_cleanup(image);
173
174 /*
175 * Above call should have called into bootloader to free up
176 * any data stored in kimage->image_loader_data. It should
177 * be ok now to free it up.
178 */
179 kfree(image->image_loader_data);
180 image->image_loader_data = NULL;
181}
182
183/*
184 * In file mode list of segments is prepared by kernel. Copy relevant
185 * data from user space, do error checking, prepare segment list
186 */
187static int
188kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
189 const char __user *cmdline_ptr,
190 unsigned long cmdline_len, unsigned flags)
191{
192 int ret = 0;
193 void *ldata;
194 loff_t size;
195
196 ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
197 &size, INT_MAX, READING_KEXEC_IMAGE);
198 if (ret)
199 return ret;
200 image->kernel_buf_len = size;
201
202 /* IMA needs to pass the measurement list to the next kernel. */
203 ima_add_kexec_buffer(image);
204
205 /* Call arch image probe handlers */
206 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
207 image->kernel_buf_len);
208 if (ret)
209 goto out;
210
211#ifdef CONFIG_KEXEC_VERIFY_SIG
212 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
213 image->kernel_buf_len);
214 if (ret) {
215 pr_debug("kernel signature verification failed.\n");
216 goto out;
217 }
218 pr_debug("kernel signature verification successful.\n");
219#endif
220 /* It is possible that there no initramfs is being loaded */
221 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
222 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
223 &size, INT_MAX,
224 READING_KEXEC_INITRAMFS);
225 if (ret)
226 goto out;
227 image->initrd_buf_len = size;
228 }
229
230 if (cmdline_len) {
231 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
232 if (IS_ERR(image->cmdline_buf)) {
233 ret = PTR_ERR(image->cmdline_buf);
234 image->cmdline_buf = NULL;
235 goto out;
236 }
237
238 image->cmdline_buf_len = cmdline_len;
239
240 /* command line should be a string with last byte null */
241 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
242 ret = -EINVAL;
243 goto out;
244 }
245 }
246
247 /* Call arch image load handlers */
248 ldata = arch_kexec_kernel_image_load(image);
249
250 if (IS_ERR(ldata)) {
251 ret = PTR_ERR(ldata);
252 goto out;
253 }
254
255 image->image_loader_data = ldata;
256out:
257 /* In case of error, free up all allocated memory in this function */
258 if (ret)
259 kimage_file_post_load_cleanup(image);
260 return ret;
261}
262
263static int
264kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
265 int initrd_fd, const char __user *cmdline_ptr,
266 unsigned long cmdline_len, unsigned long flags)
267{
268 int ret;
269 struct kimage *image;
270 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
271
272 image = do_kimage_alloc_init();
273 if (!image)
274 return -ENOMEM;
275
276 image->file_mode = 1;
277
278 if (kexec_on_panic) {
279 /* Enable special crash kernel control page alloc policy. */
280 image->control_page = crashk_res.start;
281 image->type = KEXEC_TYPE_CRASH;
282 }
283
284 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
285 cmdline_ptr, cmdline_len, flags);
286 if (ret)
287 goto out_free_image;
288
289 ret = sanity_check_segment_list(image);
290 if (ret)
291 goto out_free_post_load_bufs;
292
293 ret = -ENOMEM;
294 image->control_code_page = kimage_alloc_control_pages(image,
295 get_order(KEXEC_CONTROL_PAGE_SIZE));
296 if (!image->control_code_page) {
297 pr_err("Could not allocate control_code_buffer\n");
298 goto out_free_post_load_bufs;
299 }
300
301 if (!kexec_on_panic) {
302 image->swap_page = kimage_alloc_control_pages(image, 0);
303 if (!image->swap_page) {
304 pr_err("Could not allocate swap buffer\n");
305 goto out_free_control_pages;
306 }
307 }
308
309 *rimage = image;
310 return 0;
311out_free_control_pages:
312 kimage_free_page_list(&image->control_pages);
313out_free_post_load_bufs:
314 kimage_file_post_load_cleanup(image);
315out_free_image:
316 kfree(image);
317 return ret;
318}
319
320SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
321 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
322 unsigned long, flags)
323{
324 int ret = 0, i;
325 struct kimage **dest_image, *image;
326
327 /* We only trust the superuser with rebooting the system. */
328 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
329 return -EPERM;
330
331 /* Make sure we have a legal set of flags */
332 if (flags != (flags & KEXEC_FILE_FLAGS))
333 return -EINVAL;
334
335 image = NULL;
336
337 if (!mutex_trylock(&kexec_mutex))
338 return -EBUSY;
339
340 dest_image = &kexec_image;
341 if (flags & KEXEC_FILE_ON_CRASH) {
342 dest_image = &kexec_crash_image;
343 if (kexec_crash_image)
344 arch_kexec_unprotect_crashkres();
345 }
346
347 if (flags & KEXEC_FILE_UNLOAD)
348 goto exchange;
349
350 /*
351 * In case of crash, new kernel gets loaded in reserved region. It is
352 * same memory where old crash kernel might be loaded. Free any
353 * current crash dump kernel before we corrupt it.
354 */
355 if (flags & KEXEC_FILE_ON_CRASH)
356 kimage_free(xchg(&kexec_crash_image, NULL));
357
358 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
359 cmdline_len, flags);
360 if (ret)
361 goto out;
362
363 ret = machine_kexec_prepare(image);
364 if (ret)
365 goto out;
366
367 /*
368 * Some architecture(like S390) may touch the crash memory before
369 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
370 */
371 ret = kimage_crash_copy_vmcoreinfo(image);
372 if (ret)
373 goto out;
374
375 ret = kexec_calculate_store_digests(image);
376 if (ret)
377 goto out;
378
379 for (i = 0; i < image->nr_segments; i++) {
380 struct kexec_segment *ksegment;
381
382 ksegment = &image->segment[i];
383 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
384 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
385 ksegment->memsz);
386
387 ret = kimage_load_segment(image, &image->segment[i]);
388 if (ret)
389 goto out;
390 }
391
392 kimage_terminate(image);
393
394 /*
395 * Free up any temporary buffers allocated which are not needed
396 * after image has been loaded
397 */
398 kimage_file_post_load_cleanup(image);
399exchange:
400 image = xchg(dest_image, image);
401out:
402 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
403 arch_kexec_protect_crashkres();
404
405 mutex_unlock(&kexec_mutex);
406 kimage_free(image);
407 return ret;
408}
409
410static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
411 struct kexec_buf *kbuf)
412{
413 struct kimage *image = kbuf->image;
414 unsigned long temp_start, temp_end;
415
416 temp_end = min(end, kbuf->buf_max);
417 temp_start = temp_end - kbuf->memsz;
418
419 do {
420 /* align down start */
421 temp_start = temp_start & (~(kbuf->buf_align - 1));
422
423 if (temp_start < start || temp_start < kbuf->buf_min)
424 return 0;
425
426 temp_end = temp_start + kbuf->memsz - 1;
427
428 /*
429 * Make sure this does not conflict with any of existing
430 * segments
431 */
432 if (kimage_is_destination_range(image, temp_start, temp_end)) {
433 temp_start = temp_start - PAGE_SIZE;
434 continue;
435 }
436
437 /* We found a suitable memory range */
438 break;
439 } while (1);
440
441 /* If we are here, we found a suitable memory range */
442 kbuf->mem = temp_start;
443
444 /* Success, stop navigating through remaining System RAM ranges */
445 return 1;
446}
447
448static int locate_mem_hole_bottom_up(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_start = max(start, kbuf->buf_min);
455
456 do {
457 temp_start = ALIGN(temp_start, kbuf->buf_align);
458 temp_end = temp_start + kbuf->memsz - 1;
459
460 if (temp_end > end || temp_end > kbuf->buf_max)
461 return 0;
462 /*
463 * Make sure this does not conflict with any of existing
464 * segments
465 */
466 if (kimage_is_destination_range(image, temp_start, temp_end)) {
467 temp_start = temp_start + PAGE_SIZE;
468 continue;
469 }
470
471 /* We found a suitable memory range */
472 break;
473 } while (1);
474
475 /* If we are here, we found a suitable memory range */
476 kbuf->mem = temp_start;
477
478 /* Success, stop navigating through remaining System RAM ranges */
479 return 1;
480}
481
482static int locate_mem_hole_callback(struct resource *res, void *arg)
483{
484 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
485 u64 start = res->start, end = res->end;
486 unsigned long sz = end - start + 1;
487
488 /* Returning 0 will take to next memory range */
489 if (sz < kbuf->memsz)
490 return 0;
491
492 if (end < kbuf->buf_min || start > kbuf->buf_max)
493 return 0;
494
495 /*
496 * Allocate memory top down with-in ram range. Otherwise bottom up
497 * allocation.
498 */
499 if (kbuf->top_down)
500 return locate_mem_hole_top_down(start, end, kbuf);
501 return locate_mem_hole_bottom_up(start, end, kbuf);
502}
503
504/**
505 * arch_kexec_walk_mem - call func(data) on free memory regions
506 * @kbuf: Context info for the search. Also passed to @func.
507 * @func: Function to call for each memory region.
508 *
509 * Return: The memory walk will stop when func returns a non-zero value
510 * and that value will be returned. If all free regions are visited without
511 * func returning non-zero, then zero will be returned.
512 */
513int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
514 int (*func)(struct resource *, void *))
515{
516 if (kbuf->image->type == KEXEC_TYPE_CRASH)
517 return walk_iomem_res_desc(crashk_res.desc,
518 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
519 crashk_res.start, crashk_res.end,
520 kbuf, func);
521 else
522 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
523}
524
525/**
526 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
527 * @kbuf: Parameters for the memory search.
528 *
529 * On success, kbuf->mem will have the start address of the memory region found.
530 *
531 * Return: 0 on success, negative errno on error.
532 */
533int kexec_locate_mem_hole(struct kexec_buf *kbuf)
534{
535 int ret;
536
537 ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
538
539 return ret == 1 ? 0 : -EADDRNOTAVAIL;
540}
541
542/**
543 * kexec_add_buffer - place a buffer in a kexec segment
544 * @kbuf: Buffer contents and memory parameters.
545 *
546 * This function assumes that kexec_mutex is held.
547 * On successful return, @kbuf->mem will have the physical address of
548 * the buffer in memory.
549 *
550 * Return: 0 on success, negative errno on error.
551 */
552int kexec_add_buffer(struct kexec_buf *kbuf)
553{
554
555 struct kexec_segment *ksegment;
556 int ret;
557
558 /* Currently adding segment this way is allowed only in file mode */
559 if (!kbuf->image->file_mode)
560 return -EINVAL;
561
562 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
563 return -EINVAL;
564
565 /*
566 * Make sure we are not trying to add buffer after allocating
567 * control pages. All segments need to be placed first before
568 * any control pages are allocated. As control page allocation
569 * logic goes through list of segments to make sure there are
570 * no destination overlaps.
571 */
572 if (!list_empty(&kbuf->image->control_pages)) {
573 WARN_ON(1);
574 return -EINVAL;
575 }
576
577 /* Ensure minimum alignment needed for segments. */
578 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
579 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
580
581 /* Walk the RAM ranges and allocate a suitable range for the buffer */
582 ret = kexec_locate_mem_hole(kbuf);
583 if (ret)
584 return ret;
585
586 /* Found a suitable memory range */
587 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
588 ksegment->kbuf = kbuf->buffer;
589 ksegment->bufsz = kbuf->bufsz;
590 ksegment->mem = kbuf->mem;
591 ksegment->memsz = kbuf->memsz;
592 kbuf->image->nr_segments++;
593 return 0;
594}
595
596/* Calculate and store the digest of segments */
597static int kexec_calculate_store_digests(struct kimage *image)
598{
599 struct crypto_shash *tfm;
600 struct shash_desc *desc;
601 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
602 size_t desc_size, nullsz;
603 char *digest;
604 void *zero_buf;
605 struct kexec_sha_region *sha_regions;
606 struct purgatory_info *pi = &image->purgatory_info;
607
608 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
609 return 0;
610
611 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
612 zero_buf_sz = PAGE_SIZE;
613
614 tfm = crypto_alloc_shash("sha256", 0, 0);
615 if (IS_ERR(tfm)) {
616 ret = PTR_ERR(tfm);
617 goto out;
618 }
619
620 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
621 desc = kzalloc(desc_size, GFP_KERNEL);
622 if (!desc) {
623 ret = -ENOMEM;
624 goto out_free_tfm;
625 }
626
627 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
628 sha_regions = vzalloc(sha_region_sz);
629 if (!sha_regions)
630 goto out_free_desc;
631
632 desc->tfm = tfm;
633 desc->flags = 0;
634
635 ret = crypto_shash_init(desc);
636 if (ret < 0)
637 goto out_free_sha_regions;
638
639 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
640 if (!digest) {
641 ret = -ENOMEM;
642 goto out_free_sha_regions;
643 }
644
645 for (j = i = 0; i < image->nr_segments; i++) {
646 struct kexec_segment *ksegment;
647
648 ksegment = &image->segment[i];
649 /*
650 * Skip purgatory as it will be modified once we put digest
651 * info in purgatory.
652 */
653 if (ksegment->kbuf == pi->purgatory_buf)
654 continue;
655
656 ret = crypto_shash_update(desc, ksegment->kbuf,
657 ksegment->bufsz);
658 if (ret)
659 break;
660
661 /*
662 * Assume rest of the buffer is filled with zero and
663 * update digest accordingly.
664 */
665 nullsz = ksegment->memsz - ksegment->bufsz;
666 while (nullsz) {
667 unsigned long bytes = nullsz;
668
669 if (bytes > zero_buf_sz)
670 bytes = zero_buf_sz;
671 ret = crypto_shash_update(desc, zero_buf, bytes);
672 if (ret)
673 break;
674 nullsz -= bytes;
675 }
676
677 if (ret)
678 break;
679
680 sha_regions[j].start = ksegment->mem;
681 sha_regions[j].len = ksegment->memsz;
682 j++;
683 }
684
685 if (!ret) {
686 ret = crypto_shash_final(desc, digest);
687 if (ret)
688 goto out_free_digest;
689 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
690 sha_regions, sha_region_sz, 0);
691 if (ret)
692 goto out_free_digest;
693
694 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
695 digest, SHA256_DIGEST_SIZE, 0);
696 if (ret)
697 goto out_free_digest;
698 }
699
700out_free_digest:
701 kfree(digest);
702out_free_sha_regions:
703 vfree(sha_regions);
704out_free_desc:
705 kfree(desc);
706out_free_tfm:
707 kfree(tfm);
708out:
709 return ret;
710}
711
712#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
713/*
714 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
715 * @pi: Purgatory to be loaded.
716 * @kbuf: Buffer to setup.
717 *
718 * Allocates the memory needed for the buffer. Caller is responsible to free
719 * the memory after use.
720 *
721 * Return: 0 on success, negative errno on error.
722 */
723static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
724 struct kexec_buf *kbuf)
725{
726 const Elf_Shdr *sechdrs;
727 unsigned long bss_align;
728 unsigned long bss_sz;
729 unsigned long align;
730 int i, ret;
731
732 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
733 kbuf->buf_align = bss_align = 1;
734 kbuf->bufsz = bss_sz = 0;
735
736 for (i = 0; i < pi->ehdr->e_shnum; i++) {
737 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
738 continue;
739
740 align = sechdrs[i].sh_addralign;
741 if (sechdrs[i].sh_type != SHT_NOBITS) {
742 if (kbuf->buf_align < align)
743 kbuf->buf_align = align;
744 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
745 kbuf->bufsz += sechdrs[i].sh_size;
746 } else {
747 if (bss_align < align)
748 bss_align = align;
749 bss_sz = ALIGN(bss_sz, align);
750 bss_sz += sechdrs[i].sh_size;
751 }
752 }
753 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
754 kbuf->memsz = kbuf->bufsz + bss_sz;
755 if (kbuf->buf_align < bss_align)
756 kbuf->buf_align = bss_align;
757
758 kbuf->buffer = vzalloc(kbuf->bufsz);
759 if (!kbuf->buffer)
760 return -ENOMEM;
761 pi->purgatory_buf = kbuf->buffer;
762
763 ret = kexec_add_buffer(kbuf);
764 if (ret)
765 goto out;
766
767 return 0;
768out:
769 vfree(pi->purgatory_buf);
770 pi->purgatory_buf = NULL;
771 return ret;
772}
773
774/*
775 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
776 * @pi: Purgatory to be loaded.
777 * @kbuf: Buffer prepared to store purgatory.
778 *
779 * Allocates the memory needed for the buffer. Caller is responsible to free
780 * the memory after use.
781 *
782 * Return: 0 on success, negative errno on error.
783 */
784static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
785 struct kexec_buf *kbuf)
786{
787 unsigned long bss_addr;
788 unsigned long offset;
789 Elf_Shdr *sechdrs;
790 int i;
791
792 /*
793 * The section headers in kexec_purgatory are read-only. In order to
794 * have them modifiable make a temporary copy.
795 */
796 sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
797 if (!sechdrs)
798 return -ENOMEM;
799 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
800 pi->ehdr->e_shnum * sizeof(Elf_Shdr));
801 pi->sechdrs = sechdrs;
802
803 offset = 0;
804 bss_addr = kbuf->mem + kbuf->bufsz;
805 kbuf->image->start = pi->ehdr->e_entry;
806
807 for (i = 0; i < pi->ehdr->e_shnum; i++) {
808 unsigned long align;
809 void *src, *dst;
810
811 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
812 continue;
813
814 align = sechdrs[i].sh_addralign;
815 if (sechdrs[i].sh_type == SHT_NOBITS) {
816 bss_addr = ALIGN(bss_addr, align);
817 sechdrs[i].sh_addr = bss_addr;
818 bss_addr += sechdrs[i].sh_size;
819 continue;
820 }
821
822 offset = ALIGN(offset, align);
823 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
824 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
825 pi->ehdr->e_entry < (sechdrs[i].sh_addr
826 + sechdrs[i].sh_size)) {
827 kbuf->image->start -= sechdrs[i].sh_addr;
828 kbuf->image->start += kbuf->mem + offset;
829 }
830
831 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
832 dst = pi->purgatory_buf + offset;
833 memcpy(dst, src, sechdrs[i].sh_size);
834
835 sechdrs[i].sh_addr = kbuf->mem + offset;
836 sechdrs[i].sh_offset = offset;
837 offset += sechdrs[i].sh_size;
838 }
839
840 return 0;
841}
842
843static int kexec_apply_relocations(struct kimage *image)
844{
845 int i, ret;
846 struct purgatory_info *pi = &image->purgatory_info;
847 const Elf_Shdr *sechdrs;
848
849 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
850
851 for (i = 0; i < pi->ehdr->e_shnum; i++) {
852 const Elf_Shdr *relsec;
853 const Elf_Shdr *symtab;
854 Elf_Shdr *section;
855
856 relsec = sechdrs + i;
857
858 if (relsec->sh_type != SHT_RELA &&
859 relsec->sh_type != SHT_REL)
860 continue;
861
862 /*
863 * For section of type SHT_RELA/SHT_REL,
864 * ->sh_link contains section header index of associated
865 * symbol table. And ->sh_info contains section header
866 * index of section to which relocations apply.
867 */
868 if (relsec->sh_info >= pi->ehdr->e_shnum ||
869 relsec->sh_link >= pi->ehdr->e_shnum)
870 return -ENOEXEC;
871
872 section = pi->sechdrs + relsec->sh_info;
873 symtab = sechdrs + relsec->sh_link;
874
875 if (!(section->sh_flags & SHF_ALLOC))
876 continue;
877
878 /*
879 * symtab->sh_link contain section header index of associated
880 * string table.
881 */
882 if (symtab->sh_link >= pi->ehdr->e_shnum)
883 /* Invalid section number? */
884 continue;
885
886 /*
887 * Respective architecture needs to provide support for applying
888 * relocations of type SHT_RELA/SHT_REL.
889 */
890 if (relsec->sh_type == SHT_RELA)
891 ret = arch_kexec_apply_relocations_add(pi, section,
892 relsec, symtab);
893 else if (relsec->sh_type == SHT_REL)
894 ret = arch_kexec_apply_relocations(pi, section,
895 relsec, symtab);
896 if (ret)
897 return ret;
898 }
899
900 return 0;
901}
902
903/*
904 * kexec_load_purgatory - Load and relocate the purgatory object.
905 * @image: Image to add the purgatory to.
906 * @kbuf: Memory parameters to use.
907 *
908 * Allocates the memory needed for image->purgatory_info.sechdrs and
909 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
910 * to free the memory after use.
911 *
912 * Return: 0 on success, negative errno on error.
913 */
914int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
915{
916 struct purgatory_info *pi = &image->purgatory_info;
917 int ret;
918
919 if (kexec_purgatory_size <= 0)
920 return -EINVAL;
921
922 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
923
924 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
925 if (ret)
926 return ret;
927
928 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
929 if (ret)
930 goto out_free_kbuf;
931
932 ret = kexec_apply_relocations(image);
933 if (ret)
934 goto out;
935
936 return 0;
937out:
938 vfree(pi->sechdrs);
939 pi->sechdrs = NULL;
940out_free_kbuf:
941 vfree(pi->purgatory_buf);
942 pi->purgatory_buf = NULL;
943 return ret;
944}
945
946/*
947 * kexec_purgatory_find_symbol - find a symbol in the purgatory
948 * @pi: Purgatory to search in.
949 * @name: Name of the symbol.
950 *
951 * Return: pointer to symbol in read-only symtab on success, NULL on error.
952 */
953static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
954 const char *name)
955{
956 const Elf_Shdr *sechdrs;
957 const Elf_Ehdr *ehdr;
958 const Elf_Sym *syms;
959 const char *strtab;
960 int i, k;
961
962 if (!pi->ehdr)
963 return NULL;
964
965 ehdr = pi->ehdr;
966 sechdrs = (void *)ehdr + ehdr->e_shoff;
967
968 for (i = 0; i < ehdr->e_shnum; i++) {
969 if (sechdrs[i].sh_type != SHT_SYMTAB)
970 continue;
971
972 if (sechdrs[i].sh_link >= ehdr->e_shnum)
973 /* Invalid strtab section number */
974 continue;
975 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
976 syms = (void *)ehdr + sechdrs[i].sh_offset;
977
978 /* Go through symbols for a match */
979 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
980 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
981 continue;
982
983 if (strcmp(strtab + syms[k].st_name, name) != 0)
984 continue;
985
986 if (syms[k].st_shndx == SHN_UNDEF ||
987 syms[k].st_shndx >= ehdr->e_shnum) {
988 pr_debug("Symbol: %s has bad section index %d.\n",
989 name, syms[k].st_shndx);
990 return NULL;
991 }
992
993 /* Found the symbol we are looking for */
994 return &syms[k];
995 }
996 }
997
998 return NULL;
999}
1000
1001void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1002{
1003 struct purgatory_info *pi = &image->purgatory_info;
1004 const Elf_Sym *sym;
1005 Elf_Shdr *sechdr;
1006
1007 sym = kexec_purgatory_find_symbol(pi, name);
1008 if (!sym)
1009 return ERR_PTR(-EINVAL);
1010
1011 sechdr = &pi->sechdrs[sym->st_shndx];
1012
1013 /*
1014 * Returns the address where symbol will finally be loaded after
1015 * kexec_load_segment()
1016 */
1017 return (void *)(sechdr->sh_addr + sym->st_value);
1018}
1019
1020/*
1021 * Get or set value of a symbol. If "get_value" is true, symbol value is
1022 * returned in buf otherwise symbol value is set based on value in buf.
1023 */
1024int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1025 void *buf, unsigned int size, bool get_value)
1026{
1027 struct purgatory_info *pi = &image->purgatory_info;
1028 const Elf_Sym *sym;
1029 Elf_Shdr *sec;
1030 char *sym_buf;
1031
1032 sym = kexec_purgatory_find_symbol(pi, name);
1033 if (!sym)
1034 return -EINVAL;
1035
1036 if (sym->st_size != size) {
1037 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1038 name, (unsigned long)sym->st_size, size);
1039 return -EINVAL;
1040 }
1041
1042 sec = pi->sechdrs + sym->st_shndx;
1043
1044 if (sec->sh_type == SHT_NOBITS) {
1045 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1046 get_value ? "get" : "set");
1047 return -EINVAL;
1048 }
1049
1050 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1051
1052 if (get_value)
1053 memcpy((void *)buf, sym_buf, size);
1054 else
1055 memcpy((void *)sym_buf, buf, size);
1056
1057 return 0;
1058}
1059#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1060
1061int crash_exclude_mem_range(struct crash_mem *mem,
1062 unsigned long long mstart, unsigned long long mend)
1063{
1064 int i, j;
1065 unsigned long long start, end;
1066 struct crash_mem_range temp_range = {0, 0};
1067
1068 for (i = 0; i < mem->nr_ranges; i++) {
1069 start = mem->ranges[i].start;
1070 end = mem->ranges[i].end;
1071
1072 if (mstart > end || mend < start)
1073 continue;
1074
1075 /* Truncate any area outside of range */
1076 if (mstart < start)
1077 mstart = start;
1078 if (mend > end)
1079 mend = end;
1080
1081 /* Found completely overlapping range */
1082 if (mstart == start && mend == end) {
1083 mem->ranges[i].start = 0;
1084 mem->ranges[i].end = 0;
1085 if (i < mem->nr_ranges - 1) {
1086 /* Shift rest of the ranges to left */
1087 for (j = i; j < mem->nr_ranges - 1; j++) {
1088 mem->ranges[j].start =
1089 mem->ranges[j+1].start;
1090 mem->ranges[j].end =
1091 mem->ranges[j+1].end;
1092 }
1093 }
1094 mem->nr_ranges--;
1095 return 0;
1096 }
1097
1098 if (mstart > start && mend < end) {
1099 /* Split original range */
1100 mem->ranges[i].end = mstart - 1;
1101 temp_range.start = mend + 1;
1102 temp_range.end = end;
1103 } else if (mstart != start)
1104 mem->ranges[i].end = mstart - 1;
1105 else
1106 mem->ranges[i].start = mend + 1;
1107 break;
1108 }
1109
1110 /* If a split happened, add the split to array */
1111 if (!temp_range.end)
1112 return 0;
1113
1114 /* Split happened */
1115 if (i == mem->max_nr_ranges - 1)
1116 return -ENOMEM;
1117
1118 /* Location where new range should go */
1119 j = i + 1;
1120 if (j < mem->nr_ranges) {
1121 /* Move over all ranges one slot towards the end */
1122 for (i = mem->nr_ranges - 1; i >= j; i--)
1123 mem->ranges[i + 1] = mem->ranges[i];
1124 }
1125
1126 mem->ranges[j].start = temp_range.start;
1127 mem->ranges[j].end = temp_range.end;
1128 mem->nr_ranges++;
1129 return 0;
1130}
1131
1132int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1133 void **addr, unsigned long *sz)
1134{
1135 Elf64_Ehdr *ehdr;
1136 Elf64_Phdr *phdr;
1137 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1138 unsigned char *buf;
1139 unsigned int cpu, i;
1140 unsigned long long notes_addr;
1141 unsigned long mstart, mend;
1142
1143 /* extra phdr for vmcoreinfo elf note */
1144 nr_phdr = nr_cpus + 1;
1145 nr_phdr += mem->nr_ranges;
1146
1147 /*
1148 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1149 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1150 * I think this is required by tools like gdb. So same physical
1151 * memory will be mapped in two elf headers. One will contain kernel
1152 * text virtual addresses and other will have __va(physical) addresses.
1153 */
1154
1155 nr_phdr++;
1156 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1157 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1158
1159 buf = vzalloc(elf_sz);
1160 if (!buf)
1161 return -ENOMEM;
1162
1163 ehdr = (Elf64_Ehdr *)buf;
1164 phdr = (Elf64_Phdr *)(ehdr + 1);
1165 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1166 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1167 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1168 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1169 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1170 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1171 ehdr->e_type = ET_CORE;
1172 ehdr->e_machine = ELF_ARCH;
1173 ehdr->e_version = EV_CURRENT;
1174 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1175 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1176 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1177
1178 /* Prepare one phdr of type PT_NOTE for each present cpu */
1179 for_each_present_cpu(cpu) {
1180 phdr->p_type = PT_NOTE;
1181 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1182 phdr->p_offset = phdr->p_paddr = notes_addr;
1183 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1184 (ehdr->e_phnum)++;
1185 phdr++;
1186 }
1187
1188 /* Prepare one PT_NOTE header for vmcoreinfo */
1189 phdr->p_type = PT_NOTE;
1190 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1191 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1192 (ehdr->e_phnum)++;
1193 phdr++;
1194
1195 /* Prepare PT_LOAD type program header for kernel text region */
1196 if (kernel_map) {
1197 phdr->p_type = PT_LOAD;
1198 phdr->p_flags = PF_R|PF_W|PF_X;
1199 phdr->p_vaddr = (Elf64_Addr)_text;
1200 phdr->p_filesz = phdr->p_memsz = _end - _text;
1201 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1202 ehdr->e_phnum++;
1203 phdr++;
1204 }
1205
1206 /* Go through all the ranges in mem->ranges[] and prepare phdr */
1207 for (i = 0; i < mem->nr_ranges; i++) {
1208 mstart = mem->ranges[i].start;
1209 mend = mem->ranges[i].end;
1210
1211 phdr->p_type = PT_LOAD;
1212 phdr->p_flags = PF_R|PF_W|PF_X;
1213 phdr->p_offset = mstart;
1214
1215 phdr->p_paddr = mstart;
1216 phdr->p_vaddr = (unsigned long long) __va(mstart);
1217 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1218 phdr->p_align = 0;
1219 ehdr->e_phnum++;
1220 phdr++;
1221 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",
1222 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1223 ehdr->e_phnum, phdr->p_offset);
1224 }
1225
1226 *addr = buf;
1227 *sz = elf_sz;
1228 return 0;
1229}
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 <vgoyal@redhat.com>
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/sha.h>
24#include <linux/elf.h>
25#include <linux/elfcore.h>
26#include <linux/kernel.h>
27#include <linux/syscalls.h>
28#include <linux/vmalloc.h>
29#include "kexec_internal.h"
30
31static int kexec_calculate_store_digests(struct kimage *image);
32
33/*
34 * Currently this is the only default function that is exported as some
35 * architectures need it to do additional handlings.
36 * In the future, other default functions may be exported too if required.
37 */
38int kexec_image_probe_default(struct kimage *image, void *buf,
39 unsigned long buf_len)
40{
41 const struct kexec_file_ops * const *fops;
42 int ret = -ENOEXEC;
43
44 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
45 ret = (*fops)->probe(buf, buf_len);
46 if (!ret) {
47 image->fops = *fops;
48 return ret;
49 }
50 }
51
52 return ret;
53}
54
55/* Architectures can provide this probe function */
56int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
57 unsigned long buf_len)
58{
59 return kexec_image_probe_default(image, buf, buf_len);
60}
61
62static void *kexec_image_load_default(struct kimage *image)
63{
64 if (!image->fops || !image->fops->load)
65 return ERR_PTR(-ENOEXEC);
66
67 return image->fops->load(image, image->kernel_buf,
68 image->kernel_buf_len, image->initrd_buf,
69 image->initrd_buf_len, image->cmdline_buf,
70 image->cmdline_buf_len);
71}
72
73void * __weak arch_kexec_kernel_image_load(struct kimage *image)
74{
75 return kexec_image_load_default(image);
76}
77
78int kexec_image_post_load_cleanup_default(struct kimage *image)
79{
80 if (!image->fops || !image->fops->cleanup)
81 return 0;
82
83 return image->fops->cleanup(image->image_loader_data);
84}
85
86int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
87{
88 return kexec_image_post_load_cleanup_default(image);
89}
90
91#ifdef CONFIG_KEXEC_SIG
92static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
93 unsigned long buf_len)
94{
95 if (!image->fops || !image->fops->verify_sig) {
96 pr_debug("kernel loader does not support signature verification.\n");
97 return -EKEYREJECTED;
98 }
99
100 return image->fops->verify_sig(buf, buf_len);
101}
102
103int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
104 unsigned long buf_len)
105{
106 return kexec_image_verify_sig_default(image, buf, buf_len);
107}
108#endif
109
110/*
111 * arch_kexec_apply_relocations_add - apply relocations of type RELA
112 * @pi: Purgatory to be relocated.
113 * @section: Section relocations applying to.
114 * @relsec: Section containing RELAs.
115 * @symtab: Corresponding symtab.
116 *
117 * Return: 0 on success, negative errno on error.
118 */
119int __weak
120arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
121 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
122{
123 pr_err("RELA relocation unsupported.\n");
124 return -ENOEXEC;
125}
126
127/*
128 * arch_kexec_apply_relocations - apply relocations of type REL
129 * @pi: Purgatory to be relocated.
130 * @section: Section relocations applying to.
131 * @relsec: Section containing RELs.
132 * @symtab: Corresponding symtab.
133 *
134 * Return: 0 on success, negative errno on error.
135 */
136int __weak
137arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
138 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
139{
140 pr_err("REL relocation unsupported.\n");
141 return -ENOEXEC;
142}
143
144/*
145 * Free up memory used by kernel, initrd, and command line. This is temporary
146 * memory allocation which is not needed any more after these buffers have
147 * been loaded into separate segments and have been copied elsewhere.
148 */
149void kimage_file_post_load_cleanup(struct kimage *image)
150{
151 struct purgatory_info *pi = &image->purgatory_info;
152
153 vfree(image->kernel_buf);
154 image->kernel_buf = NULL;
155
156 vfree(image->initrd_buf);
157 image->initrd_buf = NULL;
158
159 kfree(image->cmdline_buf);
160 image->cmdline_buf = NULL;
161
162 vfree(pi->purgatory_buf);
163 pi->purgatory_buf = NULL;
164
165 vfree(pi->sechdrs);
166 pi->sechdrs = NULL;
167
168 /* See if architecture has anything to cleanup post load */
169 arch_kimage_file_post_load_cleanup(image);
170
171 /*
172 * Above call should have called into bootloader to free up
173 * any data stored in kimage->image_loader_data. It should
174 * be ok now to free it up.
175 */
176 kfree(image->image_loader_data);
177 image->image_loader_data = NULL;
178}
179
180#ifdef CONFIG_KEXEC_SIG
181static int
182kimage_validate_signature(struct kimage *image)
183{
184 int ret;
185
186 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
187 image->kernel_buf_len);
188 if (ret) {
189
190 if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
191 pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
192 return ret;
193 }
194
195 /*
196 * If IMA is guaranteed to appraise a signature on the kexec
197 * image, permit it even if the kernel is otherwise locked
198 * down.
199 */
200 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
201 security_locked_down(LOCKDOWN_KEXEC))
202 return -EPERM;
203
204 pr_debug("kernel signature verification failed (%d).\n", ret);
205 }
206
207 return 0;
208}
209#endif
210
211/*
212 * In file mode list of segments is prepared by kernel. Copy relevant
213 * data from user space, do error checking, prepare segment list
214 */
215static int
216kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
217 const char __user *cmdline_ptr,
218 unsigned long cmdline_len, unsigned flags)
219{
220 int ret;
221 void *ldata;
222 loff_t size;
223
224 ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
225 &size, INT_MAX, READING_KEXEC_IMAGE);
226 if (ret)
227 return ret;
228 image->kernel_buf_len = size;
229
230 /* Call arch image probe handlers */
231 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
232 image->kernel_buf_len);
233 if (ret)
234 goto out;
235
236#ifdef CONFIG_KEXEC_SIG
237 ret = kimage_validate_signature(image);
238
239 if (ret)
240 goto out;
241#endif
242 /* It is possible that there no initramfs is being loaded */
243 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
244 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
245 &size, INT_MAX,
246 READING_KEXEC_INITRAMFS);
247 if (ret)
248 goto out;
249 image->initrd_buf_len = size;
250 }
251
252 if (cmdline_len) {
253 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
254 if (IS_ERR(image->cmdline_buf)) {
255 ret = PTR_ERR(image->cmdline_buf);
256 image->cmdline_buf = NULL;
257 goto out;
258 }
259
260 image->cmdline_buf_len = cmdline_len;
261
262 /* command line should be a string with last byte null */
263 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
264 ret = -EINVAL;
265 goto out;
266 }
267
268 ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
269 image->cmdline_buf_len - 1);
270 }
271
272 /* IMA needs to pass the measurement list to the next kernel. */
273 ima_add_kexec_buffer(image);
274
275 /* Call arch image load handlers */
276 ldata = arch_kexec_kernel_image_load(image);
277
278 if (IS_ERR(ldata)) {
279 ret = PTR_ERR(ldata);
280 goto out;
281 }
282
283 image->image_loader_data = ldata;
284out:
285 /* In case of error, free up all allocated memory in this function */
286 if (ret)
287 kimage_file_post_load_cleanup(image);
288 return ret;
289}
290
291static int
292kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
293 int initrd_fd, const char __user *cmdline_ptr,
294 unsigned long cmdline_len, unsigned long flags)
295{
296 int ret;
297 struct kimage *image;
298 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
299
300 image = do_kimage_alloc_init();
301 if (!image)
302 return -ENOMEM;
303
304 image->file_mode = 1;
305
306 if (kexec_on_panic) {
307 /* Enable special crash kernel control page alloc policy. */
308 image->control_page = crashk_res.start;
309 image->type = KEXEC_TYPE_CRASH;
310 }
311
312 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
313 cmdline_ptr, cmdline_len, flags);
314 if (ret)
315 goto out_free_image;
316
317 ret = sanity_check_segment_list(image);
318 if (ret)
319 goto out_free_post_load_bufs;
320
321 ret = -ENOMEM;
322 image->control_code_page = kimage_alloc_control_pages(image,
323 get_order(KEXEC_CONTROL_PAGE_SIZE));
324 if (!image->control_code_page) {
325 pr_err("Could not allocate control_code_buffer\n");
326 goto out_free_post_load_bufs;
327 }
328
329 if (!kexec_on_panic) {
330 image->swap_page = kimage_alloc_control_pages(image, 0);
331 if (!image->swap_page) {
332 pr_err("Could not allocate swap buffer\n");
333 goto out_free_control_pages;
334 }
335 }
336
337 *rimage = image;
338 return 0;
339out_free_control_pages:
340 kimage_free_page_list(&image->control_pages);
341out_free_post_load_bufs:
342 kimage_file_post_load_cleanup(image);
343out_free_image:
344 kfree(image);
345 return ret;
346}
347
348SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
349 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
350 unsigned long, flags)
351{
352 int ret = 0, i;
353 struct kimage **dest_image, *image;
354
355 /* We only trust the superuser with rebooting the system. */
356 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
357 return -EPERM;
358
359 /* Make sure we have a legal set of flags */
360 if (flags != (flags & KEXEC_FILE_FLAGS))
361 return -EINVAL;
362
363 image = NULL;
364
365 if (!mutex_trylock(&kexec_mutex))
366 return -EBUSY;
367
368 dest_image = &kexec_image;
369 if (flags & KEXEC_FILE_ON_CRASH) {
370 dest_image = &kexec_crash_image;
371 if (kexec_crash_image)
372 arch_kexec_unprotect_crashkres();
373 }
374
375 if (flags & KEXEC_FILE_UNLOAD)
376 goto exchange;
377
378 /*
379 * In case of crash, new kernel gets loaded in reserved region. It is
380 * same memory where old crash kernel might be loaded. Free any
381 * current crash dump kernel before we corrupt it.
382 */
383 if (flags & KEXEC_FILE_ON_CRASH)
384 kimage_free(xchg(&kexec_crash_image, NULL));
385
386 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
387 cmdline_len, flags);
388 if (ret)
389 goto out;
390
391 ret = machine_kexec_prepare(image);
392 if (ret)
393 goto out;
394
395 /*
396 * Some architecture(like S390) may touch the crash memory before
397 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
398 */
399 ret = kimage_crash_copy_vmcoreinfo(image);
400 if (ret)
401 goto out;
402
403 ret = kexec_calculate_store_digests(image);
404 if (ret)
405 goto out;
406
407 for (i = 0; i < image->nr_segments; i++) {
408 struct kexec_segment *ksegment;
409
410 ksegment = &image->segment[i];
411 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
412 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
413 ksegment->memsz);
414
415 ret = kimage_load_segment(image, &image->segment[i]);
416 if (ret)
417 goto out;
418 }
419
420 kimage_terminate(image);
421
422 ret = machine_kexec_post_load(image);
423 if (ret)
424 goto out;
425
426 /*
427 * Free up any temporary buffers allocated which are not needed
428 * after image has been loaded
429 */
430 kimage_file_post_load_cleanup(image);
431exchange:
432 image = xchg(dest_image, image);
433out:
434 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
435 arch_kexec_protect_crashkres();
436
437 mutex_unlock(&kexec_mutex);
438 kimage_free(image);
439 return ret;
440}
441
442static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
443 struct kexec_buf *kbuf)
444{
445 struct kimage *image = kbuf->image;
446 unsigned long temp_start, temp_end;
447
448 temp_end = min(end, kbuf->buf_max);
449 temp_start = temp_end - kbuf->memsz;
450
451 do {
452 /* align down start */
453 temp_start = temp_start & (~(kbuf->buf_align - 1));
454
455 if (temp_start < start || temp_start < kbuf->buf_min)
456 return 0;
457
458 temp_end = temp_start + kbuf->memsz - 1;
459
460 /*
461 * Make sure this does not conflict with any of existing
462 * segments
463 */
464 if (kimage_is_destination_range(image, temp_start, temp_end)) {
465 temp_start = temp_start - PAGE_SIZE;
466 continue;
467 }
468
469 /* We found a suitable memory range */
470 break;
471 } while (1);
472
473 /* If we are here, we found a suitable memory range */
474 kbuf->mem = temp_start;
475
476 /* Success, stop navigating through remaining System RAM ranges */
477 return 1;
478}
479
480static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
481 struct kexec_buf *kbuf)
482{
483 struct kimage *image = kbuf->image;
484 unsigned long temp_start, temp_end;
485
486 temp_start = max(start, kbuf->buf_min);
487
488 do {
489 temp_start = ALIGN(temp_start, kbuf->buf_align);
490 temp_end = temp_start + kbuf->memsz - 1;
491
492 if (temp_end > end || temp_end > kbuf->buf_max)
493 return 0;
494 /*
495 * Make sure this does not conflict with any of existing
496 * segments
497 */
498 if (kimage_is_destination_range(image, temp_start, temp_end)) {
499 temp_start = temp_start + PAGE_SIZE;
500 continue;
501 }
502
503 /* We found a suitable memory range */
504 break;
505 } while (1);
506
507 /* If we are here, we found a suitable memory range */
508 kbuf->mem = temp_start;
509
510 /* Success, stop navigating through remaining System RAM ranges */
511 return 1;
512}
513
514static int locate_mem_hole_callback(struct resource *res, void *arg)
515{
516 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
517 u64 start = res->start, end = res->end;
518 unsigned long sz = end - start + 1;
519
520 /* Returning 0 will take to next memory range */
521
522 /* Don't use memory that will be detected and handled by a driver. */
523 if (res->flags & IORESOURCE_MEM_DRIVER_MANAGED)
524 return 0;
525
526 if (sz < kbuf->memsz)
527 return 0;
528
529 if (end < kbuf->buf_min || start > kbuf->buf_max)
530 return 0;
531
532 /*
533 * Allocate memory top down with-in ram range. Otherwise bottom up
534 * allocation.
535 */
536 if (kbuf->top_down)
537 return locate_mem_hole_top_down(start, end, kbuf);
538 return locate_mem_hole_bottom_up(start, end, kbuf);
539}
540
541#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
542static int kexec_walk_memblock(struct kexec_buf *kbuf,
543 int (*func)(struct resource *, void *))
544{
545 int ret = 0;
546 u64 i;
547 phys_addr_t mstart, mend;
548 struct resource res = { };
549
550 if (kbuf->image->type == KEXEC_TYPE_CRASH)
551 return func(&crashk_res, kbuf);
552
553 if (kbuf->top_down) {
554 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
555 &mstart, &mend, NULL) {
556 /*
557 * In memblock, end points to the first byte after the
558 * range while in kexec, end points to the last byte
559 * in the range.
560 */
561 res.start = mstart;
562 res.end = mend - 1;
563 ret = func(&res, kbuf);
564 if (ret)
565 break;
566 }
567 } else {
568 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
569 &mstart, &mend, NULL) {
570 /*
571 * In memblock, end points to the first byte after the
572 * range while in kexec, end points to the last byte
573 * in the range.
574 */
575 res.start = mstart;
576 res.end = mend - 1;
577 ret = func(&res, kbuf);
578 if (ret)
579 break;
580 }
581 }
582
583 return ret;
584}
585#else
586static int kexec_walk_memblock(struct kexec_buf *kbuf,
587 int (*func)(struct resource *, void *))
588{
589 return 0;
590}
591#endif
592
593/**
594 * kexec_walk_resources - call func(data) on free memory regions
595 * @kbuf: Context info for the search. Also passed to @func.
596 * @func: Function to call for each memory region.
597 *
598 * Return: The memory walk will stop when func returns a non-zero value
599 * and that value will be returned. If all free regions are visited without
600 * func returning non-zero, then zero will be returned.
601 */
602static int kexec_walk_resources(struct kexec_buf *kbuf,
603 int (*func)(struct resource *, void *))
604{
605 if (kbuf->image->type == KEXEC_TYPE_CRASH)
606 return walk_iomem_res_desc(crashk_res.desc,
607 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
608 crashk_res.start, crashk_res.end,
609 kbuf, func);
610 else
611 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
612}
613
614/**
615 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
616 * @kbuf: Parameters for the memory search.
617 *
618 * On success, kbuf->mem will have the start address of the memory region found.
619 *
620 * Return: 0 on success, negative errno on error.
621 */
622int kexec_locate_mem_hole(struct kexec_buf *kbuf)
623{
624 int ret;
625
626 /* Arch knows where to place */
627 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
628 return 0;
629
630 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
631 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
632 else
633 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
634
635 return ret == 1 ? 0 : -EADDRNOTAVAIL;
636}
637
638/**
639 * arch_kexec_locate_mem_hole - Find free memory to place the segments.
640 * @kbuf: Parameters for the memory search.
641 *
642 * On success, kbuf->mem will have the start address of the memory region found.
643 *
644 * Return: 0 on success, negative errno on error.
645 */
646int __weak arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
647{
648 return kexec_locate_mem_hole(kbuf);
649}
650
651/**
652 * kexec_add_buffer - place a buffer in a kexec segment
653 * @kbuf: Buffer contents and memory parameters.
654 *
655 * This function assumes that kexec_mutex is held.
656 * On successful return, @kbuf->mem will have the physical address of
657 * the buffer in memory.
658 *
659 * Return: 0 on success, negative errno on error.
660 */
661int kexec_add_buffer(struct kexec_buf *kbuf)
662{
663 struct kexec_segment *ksegment;
664 int ret;
665
666 /* Currently adding segment this way is allowed only in file mode */
667 if (!kbuf->image->file_mode)
668 return -EINVAL;
669
670 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
671 return -EINVAL;
672
673 /*
674 * Make sure we are not trying to add buffer after allocating
675 * control pages. All segments need to be placed first before
676 * any control pages are allocated. As control page allocation
677 * logic goes through list of segments to make sure there are
678 * no destination overlaps.
679 */
680 if (!list_empty(&kbuf->image->control_pages)) {
681 WARN_ON(1);
682 return -EINVAL;
683 }
684
685 /* Ensure minimum alignment needed for segments. */
686 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
687 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
688
689 /* Walk the RAM ranges and allocate a suitable range for the buffer */
690 ret = arch_kexec_locate_mem_hole(kbuf);
691 if (ret)
692 return ret;
693
694 /* Found a suitable memory range */
695 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
696 ksegment->kbuf = kbuf->buffer;
697 ksegment->bufsz = kbuf->bufsz;
698 ksegment->mem = kbuf->mem;
699 ksegment->memsz = kbuf->memsz;
700 kbuf->image->nr_segments++;
701 return 0;
702}
703
704/* Calculate and store the digest of segments */
705static int kexec_calculate_store_digests(struct kimage *image)
706{
707 struct crypto_shash *tfm;
708 struct shash_desc *desc;
709 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
710 size_t desc_size, nullsz;
711 char *digest;
712 void *zero_buf;
713 struct kexec_sha_region *sha_regions;
714 struct purgatory_info *pi = &image->purgatory_info;
715
716 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
717 return 0;
718
719 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
720 zero_buf_sz = PAGE_SIZE;
721
722 tfm = crypto_alloc_shash("sha256", 0, 0);
723 if (IS_ERR(tfm)) {
724 ret = PTR_ERR(tfm);
725 goto out;
726 }
727
728 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
729 desc = kzalloc(desc_size, GFP_KERNEL);
730 if (!desc) {
731 ret = -ENOMEM;
732 goto out_free_tfm;
733 }
734
735 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
736 sha_regions = vzalloc(sha_region_sz);
737 if (!sha_regions)
738 goto out_free_desc;
739
740 desc->tfm = tfm;
741
742 ret = crypto_shash_init(desc);
743 if (ret < 0)
744 goto out_free_sha_regions;
745
746 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
747 if (!digest) {
748 ret = -ENOMEM;
749 goto out_free_sha_regions;
750 }
751
752 for (j = i = 0; i < image->nr_segments; i++) {
753 struct kexec_segment *ksegment;
754
755 ksegment = &image->segment[i];
756 /*
757 * Skip purgatory as it will be modified once we put digest
758 * info in purgatory.
759 */
760 if (ksegment->kbuf == pi->purgatory_buf)
761 continue;
762
763 ret = crypto_shash_update(desc, ksegment->kbuf,
764 ksegment->bufsz);
765 if (ret)
766 break;
767
768 /*
769 * Assume rest of the buffer is filled with zero and
770 * update digest accordingly.
771 */
772 nullsz = ksegment->memsz - ksegment->bufsz;
773 while (nullsz) {
774 unsigned long bytes = nullsz;
775
776 if (bytes > zero_buf_sz)
777 bytes = zero_buf_sz;
778 ret = crypto_shash_update(desc, zero_buf, bytes);
779 if (ret)
780 break;
781 nullsz -= bytes;
782 }
783
784 if (ret)
785 break;
786
787 sha_regions[j].start = ksegment->mem;
788 sha_regions[j].len = ksegment->memsz;
789 j++;
790 }
791
792 if (!ret) {
793 ret = crypto_shash_final(desc, digest);
794 if (ret)
795 goto out_free_digest;
796 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
797 sha_regions, sha_region_sz, 0);
798 if (ret)
799 goto out_free_digest;
800
801 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
802 digest, SHA256_DIGEST_SIZE, 0);
803 if (ret)
804 goto out_free_digest;
805 }
806
807out_free_digest:
808 kfree(digest);
809out_free_sha_regions:
810 vfree(sha_regions);
811out_free_desc:
812 kfree(desc);
813out_free_tfm:
814 kfree(tfm);
815out:
816 return ret;
817}
818
819#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
820/*
821 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
822 * @pi: Purgatory to be loaded.
823 * @kbuf: Buffer to setup.
824 *
825 * Allocates the memory needed for the buffer. Caller is responsible to free
826 * the memory after use.
827 *
828 * Return: 0 on success, negative errno on error.
829 */
830static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
831 struct kexec_buf *kbuf)
832{
833 const Elf_Shdr *sechdrs;
834 unsigned long bss_align;
835 unsigned long bss_sz;
836 unsigned long align;
837 int i, ret;
838
839 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
840 kbuf->buf_align = bss_align = 1;
841 kbuf->bufsz = bss_sz = 0;
842
843 for (i = 0; i < pi->ehdr->e_shnum; i++) {
844 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
845 continue;
846
847 align = sechdrs[i].sh_addralign;
848 if (sechdrs[i].sh_type != SHT_NOBITS) {
849 if (kbuf->buf_align < align)
850 kbuf->buf_align = align;
851 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
852 kbuf->bufsz += sechdrs[i].sh_size;
853 } else {
854 if (bss_align < align)
855 bss_align = align;
856 bss_sz = ALIGN(bss_sz, align);
857 bss_sz += sechdrs[i].sh_size;
858 }
859 }
860 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
861 kbuf->memsz = kbuf->bufsz + bss_sz;
862 if (kbuf->buf_align < bss_align)
863 kbuf->buf_align = bss_align;
864
865 kbuf->buffer = vzalloc(kbuf->bufsz);
866 if (!kbuf->buffer)
867 return -ENOMEM;
868 pi->purgatory_buf = kbuf->buffer;
869
870 ret = kexec_add_buffer(kbuf);
871 if (ret)
872 goto out;
873
874 return 0;
875out:
876 vfree(pi->purgatory_buf);
877 pi->purgatory_buf = NULL;
878 return ret;
879}
880
881/*
882 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
883 * @pi: Purgatory to be loaded.
884 * @kbuf: Buffer prepared to store purgatory.
885 *
886 * Allocates the memory needed for the buffer. Caller is responsible to free
887 * the memory after use.
888 *
889 * Return: 0 on success, negative errno on error.
890 */
891static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
892 struct kexec_buf *kbuf)
893{
894 unsigned long bss_addr;
895 unsigned long offset;
896 Elf_Shdr *sechdrs;
897 int i;
898
899 /*
900 * The section headers in kexec_purgatory are read-only. In order to
901 * have them modifiable make a temporary copy.
902 */
903 sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
904 if (!sechdrs)
905 return -ENOMEM;
906 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
907 pi->ehdr->e_shnum * sizeof(Elf_Shdr));
908 pi->sechdrs = sechdrs;
909
910 offset = 0;
911 bss_addr = kbuf->mem + kbuf->bufsz;
912 kbuf->image->start = pi->ehdr->e_entry;
913
914 for (i = 0; i < pi->ehdr->e_shnum; i++) {
915 unsigned long align;
916 void *src, *dst;
917
918 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
919 continue;
920
921 align = sechdrs[i].sh_addralign;
922 if (sechdrs[i].sh_type == SHT_NOBITS) {
923 bss_addr = ALIGN(bss_addr, align);
924 sechdrs[i].sh_addr = bss_addr;
925 bss_addr += sechdrs[i].sh_size;
926 continue;
927 }
928
929 offset = ALIGN(offset, align);
930 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
931 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
932 pi->ehdr->e_entry < (sechdrs[i].sh_addr
933 + sechdrs[i].sh_size)) {
934 kbuf->image->start -= sechdrs[i].sh_addr;
935 kbuf->image->start += kbuf->mem + offset;
936 }
937
938 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
939 dst = pi->purgatory_buf + offset;
940 memcpy(dst, src, sechdrs[i].sh_size);
941
942 sechdrs[i].sh_addr = kbuf->mem + offset;
943 sechdrs[i].sh_offset = offset;
944 offset += sechdrs[i].sh_size;
945 }
946
947 return 0;
948}
949
950static int kexec_apply_relocations(struct kimage *image)
951{
952 int i, ret;
953 struct purgatory_info *pi = &image->purgatory_info;
954 const Elf_Shdr *sechdrs;
955
956 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
957
958 for (i = 0; i < pi->ehdr->e_shnum; i++) {
959 const Elf_Shdr *relsec;
960 const Elf_Shdr *symtab;
961 Elf_Shdr *section;
962
963 relsec = sechdrs + i;
964
965 if (relsec->sh_type != SHT_RELA &&
966 relsec->sh_type != SHT_REL)
967 continue;
968
969 /*
970 * For section of type SHT_RELA/SHT_REL,
971 * ->sh_link contains section header index of associated
972 * symbol table. And ->sh_info contains section header
973 * index of section to which relocations apply.
974 */
975 if (relsec->sh_info >= pi->ehdr->e_shnum ||
976 relsec->sh_link >= pi->ehdr->e_shnum)
977 return -ENOEXEC;
978
979 section = pi->sechdrs + relsec->sh_info;
980 symtab = sechdrs + relsec->sh_link;
981
982 if (!(section->sh_flags & SHF_ALLOC))
983 continue;
984
985 /*
986 * symtab->sh_link contain section header index of associated
987 * string table.
988 */
989 if (symtab->sh_link >= pi->ehdr->e_shnum)
990 /* Invalid section number? */
991 continue;
992
993 /*
994 * Respective architecture needs to provide support for applying
995 * relocations of type SHT_RELA/SHT_REL.
996 */
997 if (relsec->sh_type == SHT_RELA)
998 ret = arch_kexec_apply_relocations_add(pi, section,
999 relsec, symtab);
1000 else if (relsec->sh_type == SHT_REL)
1001 ret = arch_kexec_apply_relocations(pi, section,
1002 relsec, symtab);
1003 if (ret)
1004 return ret;
1005 }
1006
1007 return 0;
1008}
1009
1010/*
1011 * kexec_load_purgatory - Load and relocate the purgatory object.
1012 * @image: Image to add the purgatory to.
1013 * @kbuf: Memory parameters to use.
1014 *
1015 * Allocates the memory needed for image->purgatory_info.sechdrs and
1016 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1017 * to free the memory after use.
1018 *
1019 * Return: 0 on success, negative errno on error.
1020 */
1021int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1022{
1023 struct purgatory_info *pi = &image->purgatory_info;
1024 int ret;
1025
1026 if (kexec_purgatory_size <= 0)
1027 return -EINVAL;
1028
1029 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1030
1031 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1032 if (ret)
1033 return ret;
1034
1035 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1036 if (ret)
1037 goto out_free_kbuf;
1038
1039 ret = kexec_apply_relocations(image);
1040 if (ret)
1041 goto out;
1042
1043 return 0;
1044out:
1045 vfree(pi->sechdrs);
1046 pi->sechdrs = NULL;
1047out_free_kbuf:
1048 vfree(pi->purgatory_buf);
1049 pi->purgatory_buf = NULL;
1050 return ret;
1051}
1052
1053/*
1054 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1055 * @pi: Purgatory to search in.
1056 * @name: Name of the symbol.
1057 *
1058 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1059 */
1060static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1061 const char *name)
1062{
1063 const Elf_Shdr *sechdrs;
1064 const Elf_Ehdr *ehdr;
1065 const Elf_Sym *syms;
1066 const char *strtab;
1067 int i, k;
1068
1069 if (!pi->ehdr)
1070 return NULL;
1071
1072 ehdr = pi->ehdr;
1073 sechdrs = (void *)ehdr + ehdr->e_shoff;
1074
1075 for (i = 0; i < ehdr->e_shnum; i++) {
1076 if (sechdrs[i].sh_type != SHT_SYMTAB)
1077 continue;
1078
1079 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1080 /* Invalid strtab section number */
1081 continue;
1082 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1083 syms = (void *)ehdr + sechdrs[i].sh_offset;
1084
1085 /* Go through symbols for a match */
1086 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1087 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1088 continue;
1089
1090 if (strcmp(strtab + syms[k].st_name, name) != 0)
1091 continue;
1092
1093 if (syms[k].st_shndx == SHN_UNDEF ||
1094 syms[k].st_shndx >= ehdr->e_shnum) {
1095 pr_debug("Symbol: %s has bad section index %d.\n",
1096 name, syms[k].st_shndx);
1097 return NULL;
1098 }
1099
1100 /* Found the symbol we are looking for */
1101 return &syms[k];
1102 }
1103 }
1104
1105 return NULL;
1106}
1107
1108void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1109{
1110 struct purgatory_info *pi = &image->purgatory_info;
1111 const Elf_Sym *sym;
1112 Elf_Shdr *sechdr;
1113
1114 sym = kexec_purgatory_find_symbol(pi, name);
1115 if (!sym)
1116 return ERR_PTR(-EINVAL);
1117
1118 sechdr = &pi->sechdrs[sym->st_shndx];
1119
1120 /*
1121 * Returns the address where symbol will finally be loaded after
1122 * kexec_load_segment()
1123 */
1124 return (void *)(sechdr->sh_addr + sym->st_value);
1125}
1126
1127/*
1128 * Get or set value of a symbol. If "get_value" is true, symbol value is
1129 * returned in buf otherwise symbol value is set based on value in buf.
1130 */
1131int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1132 void *buf, unsigned int size, bool get_value)
1133{
1134 struct purgatory_info *pi = &image->purgatory_info;
1135 const Elf_Sym *sym;
1136 Elf_Shdr *sec;
1137 char *sym_buf;
1138
1139 sym = kexec_purgatory_find_symbol(pi, name);
1140 if (!sym)
1141 return -EINVAL;
1142
1143 if (sym->st_size != size) {
1144 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1145 name, (unsigned long)sym->st_size, size);
1146 return -EINVAL;
1147 }
1148
1149 sec = pi->sechdrs + sym->st_shndx;
1150
1151 if (sec->sh_type == SHT_NOBITS) {
1152 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1153 get_value ? "get" : "set");
1154 return -EINVAL;
1155 }
1156
1157 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1158
1159 if (get_value)
1160 memcpy((void *)buf, sym_buf, size);
1161 else
1162 memcpy((void *)sym_buf, buf, size);
1163
1164 return 0;
1165}
1166#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1167
1168int crash_exclude_mem_range(struct crash_mem *mem,
1169 unsigned long long mstart, unsigned long long mend)
1170{
1171 int i, j;
1172 unsigned long long start, end, p_start, p_end;
1173 struct crash_mem_range temp_range = {0, 0};
1174
1175 for (i = 0; i < mem->nr_ranges; i++) {
1176 start = mem->ranges[i].start;
1177 end = mem->ranges[i].end;
1178 p_start = mstart;
1179 p_end = mend;
1180
1181 if (mstart > end || mend < start)
1182 continue;
1183
1184 /* Truncate any area outside of range */
1185 if (mstart < start)
1186 p_start = start;
1187 if (mend > end)
1188 p_end = end;
1189
1190 /* Found completely overlapping range */
1191 if (p_start == start && p_end == end) {
1192 mem->ranges[i].start = 0;
1193 mem->ranges[i].end = 0;
1194 if (i < mem->nr_ranges - 1) {
1195 /* Shift rest of the ranges to left */
1196 for (j = i; j < mem->nr_ranges - 1; j++) {
1197 mem->ranges[j].start =
1198 mem->ranges[j+1].start;
1199 mem->ranges[j].end =
1200 mem->ranges[j+1].end;
1201 }
1202
1203 /*
1204 * Continue to check if there are another overlapping ranges
1205 * from the current position because of shifting the above
1206 * mem ranges.
1207 */
1208 i--;
1209 mem->nr_ranges--;
1210 continue;
1211 }
1212 mem->nr_ranges--;
1213 return 0;
1214 }
1215
1216 if (p_start > start && p_end < end) {
1217 /* Split original range */
1218 mem->ranges[i].end = p_start - 1;
1219 temp_range.start = p_end + 1;
1220 temp_range.end = end;
1221 } else if (p_start != start)
1222 mem->ranges[i].end = p_start - 1;
1223 else
1224 mem->ranges[i].start = p_end + 1;
1225 break;
1226 }
1227
1228 /* If a split happened, add the split to array */
1229 if (!temp_range.end)
1230 return 0;
1231
1232 /* Split happened */
1233 if (i == mem->max_nr_ranges - 1)
1234 return -ENOMEM;
1235
1236 /* Location where new range should go */
1237 j = i + 1;
1238 if (j < mem->nr_ranges) {
1239 /* Move over all ranges one slot towards the end */
1240 for (i = mem->nr_ranges - 1; i >= j; i--)
1241 mem->ranges[i + 1] = mem->ranges[i];
1242 }
1243
1244 mem->ranges[j].start = temp_range.start;
1245 mem->ranges[j].end = temp_range.end;
1246 mem->nr_ranges++;
1247 return 0;
1248}
1249
1250int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1251 void **addr, unsigned long *sz)
1252{
1253 Elf64_Ehdr *ehdr;
1254 Elf64_Phdr *phdr;
1255 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1256 unsigned char *buf;
1257 unsigned int cpu, i;
1258 unsigned long long notes_addr;
1259 unsigned long mstart, mend;
1260
1261 /* extra phdr for vmcoreinfo ELF note */
1262 nr_phdr = nr_cpus + 1;
1263 nr_phdr += mem->nr_ranges;
1264
1265 /*
1266 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1267 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1268 * I think this is required by tools like gdb. So same physical
1269 * memory will be mapped in two ELF headers. One will contain kernel
1270 * text virtual addresses and other will have __va(physical) addresses.
1271 */
1272
1273 nr_phdr++;
1274 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1275 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1276
1277 buf = vzalloc(elf_sz);
1278 if (!buf)
1279 return -ENOMEM;
1280
1281 ehdr = (Elf64_Ehdr *)buf;
1282 phdr = (Elf64_Phdr *)(ehdr + 1);
1283 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1284 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1285 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1286 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1287 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1288 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1289 ehdr->e_type = ET_CORE;
1290 ehdr->e_machine = ELF_ARCH;
1291 ehdr->e_version = EV_CURRENT;
1292 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1293 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1294 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1295
1296 /* Prepare one phdr of type PT_NOTE for each present CPU */
1297 for_each_present_cpu(cpu) {
1298 phdr->p_type = PT_NOTE;
1299 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1300 phdr->p_offset = phdr->p_paddr = notes_addr;
1301 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1302 (ehdr->e_phnum)++;
1303 phdr++;
1304 }
1305
1306 /* Prepare one PT_NOTE header for vmcoreinfo */
1307 phdr->p_type = PT_NOTE;
1308 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1309 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1310 (ehdr->e_phnum)++;
1311 phdr++;
1312
1313 /* Prepare PT_LOAD type program header for kernel text region */
1314 if (kernel_map) {
1315 phdr->p_type = PT_LOAD;
1316 phdr->p_flags = PF_R|PF_W|PF_X;
1317 phdr->p_vaddr = (unsigned long) _text;
1318 phdr->p_filesz = phdr->p_memsz = _end - _text;
1319 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1320 ehdr->e_phnum++;
1321 phdr++;
1322 }
1323
1324 /* Go through all the ranges in mem->ranges[] and prepare phdr */
1325 for (i = 0; i < mem->nr_ranges; i++) {
1326 mstart = mem->ranges[i].start;
1327 mend = mem->ranges[i].end;
1328
1329 phdr->p_type = PT_LOAD;
1330 phdr->p_flags = PF_R|PF_W|PF_X;
1331 phdr->p_offset = mstart;
1332
1333 phdr->p_paddr = mstart;
1334 phdr->p_vaddr = (unsigned long) __va(mstart);
1335 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1336 phdr->p_align = 0;
1337 ehdr->e_phnum++;
1338 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",
1339 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1340 ehdr->e_phnum, phdr->p_offset);
1341 phdr++;
1342 }
1343
1344 *addr = buf;
1345 *sz = elf_sz;
1346 return 0;
1347}