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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 <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/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
32#ifdef CONFIG_KEXEC_SIG
33static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE);
34
35void set_kexec_sig_enforced(void)
36{
37 sig_enforce = true;
38}
39#endif
40
41static int kexec_calculate_store_digests(struct kimage *image);
42
43/* Maximum size in bytes for kernel/initrd files. */
44#define KEXEC_FILE_SIZE_MAX min_t(s64, 4LL << 30, SSIZE_MAX)
45
46/*
47 * Currently this is the only default function that is exported as some
48 * architectures need it to do additional handlings.
49 * In the future, other default functions may be exported too if required.
50 */
51int kexec_image_probe_default(struct kimage *image, void *buf,
52 unsigned long buf_len)
53{
54 const struct kexec_file_ops * const *fops;
55 int ret = -ENOEXEC;
56
57 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
58 ret = (*fops)->probe(buf, buf_len);
59 if (!ret) {
60 image->fops = *fops;
61 return ret;
62 }
63 }
64
65 return ret;
66}
67
68static void *kexec_image_load_default(struct kimage *image)
69{
70 if (!image->fops || !image->fops->load)
71 return ERR_PTR(-ENOEXEC);
72
73 return image->fops->load(image, image->kernel_buf,
74 image->kernel_buf_len, image->initrd_buf,
75 image->initrd_buf_len, image->cmdline_buf,
76 image->cmdline_buf_len);
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
87/*
88 * Free up memory used by kernel, initrd, and command line. This is temporary
89 * memory allocation which is not needed any more after these buffers have
90 * been loaded into separate segments and have been copied elsewhere.
91 */
92void kimage_file_post_load_cleanup(struct kimage *image)
93{
94 struct purgatory_info *pi = &image->purgatory_info;
95
96 vfree(image->kernel_buf);
97 image->kernel_buf = NULL;
98
99 vfree(image->initrd_buf);
100 image->initrd_buf = NULL;
101
102 kfree(image->cmdline_buf);
103 image->cmdline_buf = NULL;
104
105 vfree(pi->purgatory_buf);
106 pi->purgatory_buf = NULL;
107
108 vfree(pi->sechdrs);
109 pi->sechdrs = NULL;
110
111#ifdef CONFIG_IMA_KEXEC
112 vfree(image->ima_buffer);
113 image->ima_buffer = NULL;
114#endif /* CONFIG_IMA_KEXEC */
115
116 /* See if architecture has anything to cleanup post load */
117 arch_kimage_file_post_load_cleanup(image);
118
119 /*
120 * Above call should have called into bootloader to free up
121 * any data stored in kimage->image_loader_data. It should
122 * be ok now to free it up.
123 */
124 kfree(image->image_loader_data);
125 image->image_loader_data = NULL;
126
127 kexec_file_dbg_print = false;
128}
129
130#ifdef CONFIG_KEXEC_SIG
131#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
132int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
133{
134 int ret;
135
136 ret = verify_pefile_signature(kernel, kernel_len,
137 VERIFY_USE_SECONDARY_KEYRING,
138 VERIFYING_KEXEC_PE_SIGNATURE);
139 if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
140 ret = verify_pefile_signature(kernel, kernel_len,
141 VERIFY_USE_PLATFORM_KEYRING,
142 VERIFYING_KEXEC_PE_SIGNATURE);
143 }
144 return ret;
145}
146#endif
147
148static int kexec_image_verify_sig(struct kimage *image, void *buf,
149 unsigned long buf_len)
150{
151 if (!image->fops || !image->fops->verify_sig) {
152 pr_debug("kernel loader does not support signature verification.\n");
153 return -EKEYREJECTED;
154 }
155
156 return image->fops->verify_sig(buf, buf_len);
157}
158
159static int
160kimage_validate_signature(struct kimage *image)
161{
162 int ret;
163
164 ret = kexec_image_verify_sig(image, image->kernel_buf,
165 image->kernel_buf_len);
166 if (ret) {
167
168 if (sig_enforce) {
169 pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
170 return ret;
171 }
172
173 /*
174 * If IMA is guaranteed to appraise a signature on the kexec
175 * image, permit it even if the kernel is otherwise locked
176 * down.
177 */
178 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
179 security_locked_down(LOCKDOWN_KEXEC))
180 return -EPERM;
181
182 pr_debug("kernel signature verification failed (%d).\n", ret);
183 }
184
185 return 0;
186}
187#endif
188
189/*
190 * In file mode list of segments is prepared by kernel. Copy relevant
191 * data from user space, do error checking, prepare segment list
192 */
193static int
194kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
195 const char __user *cmdline_ptr,
196 unsigned long cmdline_len, unsigned flags)
197{
198 ssize_t ret;
199 void *ldata;
200
201 ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
202 KEXEC_FILE_SIZE_MAX, NULL,
203 READING_KEXEC_IMAGE);
204 if (ret < 0)
205 return ret;
206 image->kernel_buf_len = ret;
207 kexec_dprintk("kernel: %p kernel_size: %#lx\n",
208 image->kernel_buf, image->kernel_buf_len);
209
210 /* Call arch image probe handlers */
211 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
212 image->kernel_buf_len);
213 if (ret)
214 goto out;
215
216#ifdef CONFIG_KEXEC_SIG
217 ret = kimage_validate_signature(image);
218
219 if (ret)
220 goto out;
221#endif
222 /* It is possible that there no initramfs is being loaded */
223 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
224 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
225 KEXEC_FILE_SIZE_MAX, NULL,
226 READING_KEXEC_INITRAMFS);
227 if (ret < 0)
228 goto out;
229 image->initrd_buf_len = ret;
230 ret = 0;
231 }
232
233 if (cmdline_len) {
234 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
235 if (IS_ERR(image->cmdline_buf)) {
236 ret = PTR_ERR(image->cmdline_buf);
237 image->cmdline_buf = NULL;
238 goto out;
239 }
240
241 image->cmdline_buf_len = cmdline_len;
242
243 /* command line should be a string with last byte null */
244 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
245 ret = -EINVAL;
246 goto out;
247 }
248
249 ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
250 image->cmdline_buf_len - 1);
251 }
252
253 /* IMA needs to pass the measurement list to the next kernel. */
254 ima_add_kexec_buffer(image);
255
256 /* Call image load handler */
257 ldata = kexec_image_load_default(image);
258
259 if (IS_ERR(ldata)) {
260 ret = PTR_ERR(ldata);
261 goto out;
262 }
263
264 image->image_loader_data = ldata;
265out:
266 /* In case of error, free up all allocated memory in this function */
267 if (ret)
268 kimage_file_post_load_cleanup(image);
269 return ret;
270}
271
272static int
273kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
274 int initrd_fd, const char __user *cmdline_ptr,
275 unsigned long cmdline_len, unsigned long flags)
276{
277 int ret;
278 struct kimage *image;
279 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
280
281 image = do_kimage_alloc_init();
282 if (!image)
283 return -ENOMEM;
284
285 kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
286 image->file_mode = 1;
287
288#ifdef CONFIG_CRASH_DUMP
289 if (kexec_on_panic) {
290 /* Enable special crash kernel control page alloc policy. */
291 image->control_page = crashk_res.start;
292 image->type = KEXEC_TYPE_CRASH;
293 }
294#endif
295
296 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
297 cmdline_ptr, cmdline_len, flags);
298 if (ret)
299 goto out_free_image;
300
301 ret = sanity_check_segment_list(image);
302 if (ret)
303 goto out_free_post_load_bufs;
304
305 ret = -ENOMEM;
306 image->control_code_page = kimage_alloc_control_pages(image,
307 get_order(KEXEC_CONTROL_PAGE_SIZE));
308 if (!image->control_code_page) {
309 pr_err("Could not allocate control_code_buffer\n");
310 goto out_free_post_load_bufs;
311 }
312
313 if (!kexec_on_panic) {
314 image->swap_page = kimage_alloc_control_pages(image, 0);
315 if (!image->swap_page) {
316 pr_err("Could not allocate swap buffer\n");
317 goto out_free_control_pages;
318 }
319 }
320
321 *rimage = image;
322 return 0;
323out_free_control_pages:
324 kimage_free_page_list(&image->control_pages);
325out_free_post_load_bufs:
326 kimage_file_post_load_cleanup(image);
327out_free_image:
328 kfree(image);
329 return ret;
330}
331
332SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
333 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
334 unsigned long, flags)
335{
336 int image_type = (flags & KEXEC_FILE_ON_CRASH) ?
337 KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT;
338 struct kimage **dest_image, *image;
339 int ret = 0, i;
340
341 /* We only trust the superuser with rebooting the system. */
342 if (!kexec_load_permitted(image_type))
343 return -EPERM;
344
345 /* Make sure we have a legal set of flags */
346 if (flags != (flags & KEXEC_FILE_FLAGS))
347 return -EINVAL;
348
349 image = NULL;
350
351 if (!kexec_trylock())
352 return -EBUSY;
353
354#ifdef CONFIG_CRASH_DUMP
355 if (image_type == KEXEC_TYPE_CRASH) {
356 dest_image = &kexec_crash_image;
357 if (kexec_crash_image)
358 arch_kexec_unprotect_crashkres();
359 } else
360#endif
361 dest_image = &kexec_image;
362
363 if (flags & KEXEC_FILE_UNLOAD)
364 goto exchange;
365
366 /*
367 * In case of crash, new kernel gets loaded in reserved region. It is
368 * same memory where old crash kernel might be loaded. Free any
369 * current crash dump kernel before we corrupt it.
370 */
371 if (flags & KEXEC_FILE_ON_CRASH)
372 kimage_free(xchg(&kexec_crash_image, NULL));
373
374 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
375 cmdline_len, flags);
376 if (ret)
377 goto out;
378
379 ret = machine_kexec_prepare(image);
380 if (ret)
381 goto out;
382
383 /*
384 * Some architecture(like S390) may touch the crash memory before
385 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
386 */
387 ret = kimage_crash_copy_vmcoreinfo(image);
388 if (ret)
389 goto out;
390
391 ret = kexec_calculate_store_digests(image);
392 if (ret)
393 goto out;
394
395 kexec_dprintk("nr_segments = %lu\n", image->nr_segments);
396 for (i = 0; i < image->nr_segments; i++) {
397 struct kexec_segment *ksegment;
398
399 ksegment = &image->segment[i];
400 kexec_dprintk("segment[%d]: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
401 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
402 ksegment->memsz);
403
404 ret = kimage_load_segment(image, &image->segment[i]);
405 if (ret)
406 goto out;
407 }
408
409 kimage_terminate(image);
410
411 ret = machine_kexec_post_load(image);
412 if (ret)
413 goto out;
414
415 kexec_dprintk("kexec_file_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n",
416 image->type, image->start, image->head, flags);
417 /*
418 * Free up any temporary buffers allocated which are not needed
419 * after image has been loaded
420 */
421 kimage_file_post_load_cleanup(image);
422exchange:
423 image = xchg(dest_image, image);
424out:
425#ifdef CONFIG_CRASH_DUMP
426 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
427 arch_kexec_protect_crashkres();
428#endif
429
430 kexec_unlock();
431 kimage_free(image);
432 return ret;
433}
434
435static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
436 struct kexec_buf *kbuf)
437{
438 struct kimage *image = kbuf->image;
439 unsigned long temp_start, temp_end;
440
441 temp_end = min(end, kbuf->buf_max);
442 temp_start = temp_end - kbuf->memsz + 1;
443
444 do {
445 /* align down start */
446 temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align);
447
448 if (temp_start < start || temp_start < kbuf->buf_min)
449 return 0;
450
451 temp_end = temp_start + kbuf->memsz - 1;
452
453 /*
454 * Make sure this does not conflict with any of existing
455 * segments
456 */
457 if (kimage_is_destination_range(image, temp_start, temp_end)) {
458 temp_start = temp_start - PAGE_SIZE;
459 continue;
460 }
461
462 /* We found a suitable memory range */
463 break;
464 } while (1);
465
466 /* If we are here, we found a suitable memory range */
467 kbuf->mem = temp_start;
468
469 /* Success, stop navigating through remaining System RAM ranges */
470 return 1;
471}
472
473static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
474 struct kexec_buf *kbuf)
475{
476 struct kimage *image = kbuf->image;
477 unsigned long temp_start, temp_end;
478
479 temp_start = max(start, kbuf->buf_min);
480
481 do {
482 temp_start = ALIGN(temp_start, kbuf->buf_align);
483 temp_end = temp_start + kbuf->memsz - 1;
484
485 if (temp_end > end || temp_end > kbuf->buf_max)
486 return 0;
487 /*
488 * Make sure this does not conflict with any of existing
489 * segments
490 */
491 if (kimage_is_destination_range(image, temp_start, temp_end)) {
492 temp_start = temp_start + PAGE_SIZE;
493 continue;
494 }
495
496 /* We found a suitable memory range */
497 break;
498 } while (1);
499
500 /* If we are here, we found a suitable memory range */
501 kbuf->mem = temp_start;
502
503 /* Success, stop navigating through remaining System RAM ranges */
504 return 1;
505}
506
507static int locate_mem_hole_callback(struct resource *res, void *arg)
508{
509 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
510 u64 start = res->start, end = res->end;
511 unsigned long sz = end - start + 1;
512
513 /* Returning 0 will take to next memory range */
514
515 /* Don't use memory that will be detected and handled by a driver. */
516 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
517 return 0;
518
519 if (sz < kbuf->memsz)
520 return 0;
521
522 if (end < kbuf->buf_min || start > kbuf->buf_max)
523 return 0;
524
525 /*
526 * Allocate memory top down with-in ram range. Otherwise bottom up
527 * allocation.
528 */
529 if (kbuf->top_down)
530 return locate_mem_hole_top_down(start, end, kbuf);
531 return locate_mem_hole_bottom_up(start, end, kbuf);
532}
533
534#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
535static int kexec_walk_memblock(struct kexec_buf *kbuf,
536 int (*func)(struct resource *, void *))
537{
538 int ret = 0;
539 u64 i;
540 phys_addr_t mstart, mend;
541 struct resource res = { };
542
543#ifdef CONFIG_CRASH_DUMP
544 if (kbuf->image->type == KEXEC_TYPE_CRASH)
545 return func(&crashk_res, kbuf);
546#endif
547
548 /*
549 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
550 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
551 * locate_mem_hole_callback().
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#ifdef CONFIG_CRASH_DUMP
606 if (kbuf->image->type == KEXEC_TYPE_CRASH)
607 return walk_iomem_res_desc(crashk_res.desc,
608 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
609 crashk_res.start, crashk_res.end,
610 kbuf, func);
611#endif
612 if (kbuf->top_down)
613 return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func);
614 else
615 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
616}
617
618/**
619 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
620 * @kbuf: Parameters for the memory search.
621 *
622 * On success, kbuf->mem will have the start address of the memory region found.
623 *
624 * Return: 0 on success, negative errno on error.
625 */
626int kexec_locate_mem_hole(struct kexec_buf *kbuf)
627{
628 int ret;
629
630 /* Arch knows where to place */
631 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
632 return 0;
633
634 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
635 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
636 else
637 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
638
639 return ret == 1 ? 0 : -EADDRNOTAVAIL;
640}
641
642/**
643 * kexec_add_buffer - place a buffer in a kexec segment
644 * @kbuf: Buffer contents and memory parameters.
645 *
646 * This function assumes that kexec_lock is held.
647 * On successful return, @kbuf->mem will have the physical address of
648 * the buffer in memory.
649 *
650 * Return: 0 on success, negative errno on error.
651 */
652int kexec_add_buffer(struct kexec_buf *kbuf)
653{
654 struct kexec_segment *ksegment;
655 int ret;
656
657 /* Currently adding segment this way is allowed only in file mode */
658 if (!kbuf->image->file_mode)
659 return -EINVAL;
660
661 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
662 return -EINVAL;
663
664 /*
665 * Make sure we are not trying to add buffer after allocating
666 * control pages. All segments need to be placed first before
667 * any control pages are allocated. As control page allocation
668 * logic goes through list of segments to make sure there are
669 * no destination overlaps.
670 */
671 if (!list_empty(&kbuf->image->control_pages)) {
672 WARN_ON(1);
673 return -EINVAL;
674 }
675
676 /* Ensure minimum alignment needed for segments. */
677 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
678 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
679
680 /* Walk the RAM ranges and allocate a suitable range for the buffer */
681 ret = arch_kexec_locate_mem_hole(kbuf);
682 if (ret)
683 return ret;
684
685 /* Found a suitable memory range */
686 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
687 ksegment->kbuf = kbuf->buffer;
688 ksegment->bufsz = kbuf->bufsz;
689 ksegment->mem = kbuf->mem;
690 ksegment->memsz = kbuf->memsz;
691 kbuf->image->nr_segments++;
692 return 0;
693}
694
695/* Calculate and store the digest of segments */
696static int kexec_calculate_store_digests(struct kimage *image)
697{
698 struct crypto_shash *tfm;
699 struct shash_desc *desc;
700 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
701 size_t desc_size, nullsz;
702 char *digest;
703 void *zero_buf;
704 struct kexec_sha_region *sha_regions;
705 struct purgatory_info *pi = &image->purgatory_info;
706
707 if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY))
708 return 0;
709
710 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
711 zero_buf_sz = PAGE_SIZE;
712
713 tfm = crypto_alloc_shash("sha256", 0, 0);
714 if (IS_ERR(tfm)) {
715 ret = PTR_ERR(tfm);
716 goto out;
717 }
718
719 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
720 desc = kzalloc(desc_size, GFP_KERNEL);
721 if (!desc) {
722 ret = -ENOMEM;
723 goto out_free_tfm;
724 }
725
726 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
727 sha_regions = vzalloc(sha_region_sz);
728 if (!sha_regions) {
729 ret = -ENOMEM;
730 goto out_free_desc;
731 }
732
733 desc->tfm = tfm;
734
735 ret = crypto_shash_init(desc);
736 if (ret < 0)
737 goto out_free_sha_regions;
738
739 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
740 if (!digest) {
741 ret = -ENOMEM;
742 goto out_free_sha_regions;
743 }
744
745 for (j = i = 0; i < image->nr_segments; i++) {
746 struct kexec_segment *ksegment;
747
748#ifdef CONFIG_CRASH_HOTPLUG
749 /* Exclude elfcorehdr segment to allow future changes via hotplug */
750 if (j == image->elfcorehdr_index)
751 continue;
752#endif
753
754 ksegment = &image->segment[i];
755 /*
756 * Skip purgatory as it will be modified once we put digest
757 * info in purgatory.
758 */
759 if (ksegment->kbuf == pi->purgatory_buf)
760 continue;
761
762 ret = crypto_shash_update(desc, ksegment->kbuf,
763 ksegment->bufsz);
764 if (ret)
765 break;
766
767 /*
768 * Assume rest of the buffer is filled with zero and
769 * update digest accordingly.
770 */
771 nullsz = ksegment->memsz - ksegment->bufsz;
772 while (nullsz) {
773 unsigned long bytes = nullsz;
774
775 if (bytes > zero_buf_sz)
776 bytes = zero_buf_sz;
777 ret = crypto_shash_update(desc, zero_buf, bytes);
778 if (ret)
779 break;
780 nullsz -= bytes;
781 }
782
783 if (ret)
784 break;
785
786 sha_regions[j].start = ksegment->mem;
787 sha_regions[j].len = ksegment->memsz;
788 j++;
789 }
790
791 if (!ret) {
792 ret = crypto_shash_final(desc, digest);
793 if (ret)
794 goto out_free_digest;
795 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
796 sha_regions, sha_region_sz, 0);
797 if (ret)
798 goto out_free_digest;
799
800 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
801 digest, SHA256_DIGEST_SIZE, 0);
802 if (ret)
803 goto out_free_digest;
804 }
805
806out_free_digest:
807 kfree(digest);
808out_free_sha_regions:
809 vfree(sha_regions);
810out_free_desc:
811 kfree(desc);
812out_free_tfm:
813 kfree(tfm);
814out:
815 return ret;
816}
817
818#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
819/*
820 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
821 * @pi: Purgatory to be loaded.
822 * @kbuf: Buffer to setup.
823 *
824 * Allocates the memory needed for the buffer. Caller is responsible to free
825 * the memory after use.
826 *
827 * Return: 0 on success, negative errno on error.
828 */
829static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
830 struct kexec_buf *kbuf)
831{
832 const Elf_Shdr *sechdrs;
833 unsigned long bss_align;
834 unsigned long bss_sz;
835 unsigned long align;
836 int i, ret;
837
838 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
839 kbuf->buf_align = bss_align = 1;
840 kbuf->bufsz = bss_sz = 0;
841
842 for (i = 0; i < pi->ehdr->e_shnum; i++) {
843 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
844 continue;
845
846 align = sechdrs[i].sh_addralign;
847 if (sechdrs[i].sh_type != SHT_NOBITS) {
848 if (kbuf->buf_align < align)
849 kbuf->buf_align = align;
850 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
851 kbuf->bufsz += sechdrs[i].sh_size;
852 } else {
853 if (bss_align < align)
854 bss_align = align;
855 bss_sz = ALIGN(bss_sz, align);
856 bss_sz += sechdrs[i].sh_size;
857 }
858 }
859 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
860 kbuf->memsz = kbuf->bufsz + bss_sz;
861 if (kbuf->buf_align < bss_align)
862 kbuf->buf_align = bss_align;
863
864 kbuf->buffer = vzalloc(kbuf->bufsz);
865 if (!kbuf->buffer)
866 return -ENOMEM;
867 pi->purgatory_buf = kbuf->buffer;
868
869 ret = kexec_add_buffer(kbuf);
870 if (ret)
871 goto out;
872
873 return 0;
874out:
875 vfree(pi->purgatory_buf);
876 pi->purgatory_buf = NULL;
877 return ret;
878}
879
880/*
881 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
882 * @pi: Purgatory to be loaded.
883 * @kbuf: Buffer prepared to store purgatory.
884 *
885 * Allocates the memory needed for the buffer. Caller is responsible to free
886 * the memory after use.
887 *
888 * Return: 0 on success, negative errno on error.
889 */
890static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
891 struct kexec_buf *kbuf)
892{
893 unsigned long bss_addr;
894 unsigned long offset;
895 size_t sechdrs_size;
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_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
904 sechdrs = vzalloc(sechdrs_size);
905 if (!sechdrs)
906 return -ENOMEM;
907 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
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
931 /*
932 * Check if the segment contains the entry point, if so,
933 * calculate the value of image->start based on it.
934 * If the compiler has produced more than one .text section
935 * (Eg: .text.hot), they are generally after the main .text
936 * section, and they shall not be used to calculate
937 * image->start. So do not re-calculate image->start if it
938 * is not set to the initial value, and warn the user so they
939 * have a chance to fix their purgatory's linker script.
940 */
941 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
942 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
943 pi->ehdr->e_entry < (sechdrs[i].sh_addr
944 + sechdrs[i].sh_size) &&
945 !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
946 kbuf->image->start -= sechdrs[i].sh_addr;
947 kbuf->image->start += kbuf->mem + offset;
948 }
949
950 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
951 dst = pi->purgatory_buf + offset;
952 memcpy(dst, src, sechdrs[i].sh_size);
953
954 sechdrs[i].sh_addr = kbuf->mem + offset;
955 sechdrs[i].sh_offset = offset;
956 offset += sechdrs[i].sh_size;
957 }
958
959 return 0;
960}
961
962static int kexec_apply_relocations(struct kimage *image)
963{
964 int i, ret;
965 struct purgatory_info *pi = &image->purgatory_info;
966 const Elf_Shdr *sechdrs;
967
968 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
969
970 for (i = 0; i < pi->ehdr->e_shnum; i++) {
971 const Elf_Shdr *relsec;
972 const Elf_Shdr *symtab;
973 Elf_Shdr *section;
974
975 relsec = sechdrs + i;
976
977 if (relsec->sh_type != SHT_RELA &&
978 relsec->sh_type != SHT_REL)
979 continue;
980
981 /*
982 * For section of type SHT_RELA/SHT_REL,
983 * ->sh_link contains section header index of associated
984 * symbol table. And ->sh_info contains section header
985 * index of section to which relocations apply.
986 */
987 if (relsec->sh_info >= pi->ehdr->e_shnum ||
988 relsec->sh_link >= pi->ehdr->e_shnum)
989 return -ENOEXEC;
990
991 section = pi->sechdrs + relsec->sh_info;
992 symtab = sechdrs + relsec->sh_link;
993
994 if (!(section->sh_flags & SHF_ALLOC))
995 continue;
996
997 /*
998 * symtab->sh_link contain section header index of associated
999 * string table.
1000 */
1001 if (symtab->sh_link >= pi->ehdr->e_shnum)
1002 /* Invalid section number? */
1003 continue;
1004
1005 /*
1006 * Respective architecture needs to provide support for applying
1007 * relocations of type SHT_RELA/SHT_REL.
1008 */
1009 if (relsec->sh_type == SHT_RELA)
1010 ret = arch_kexec_apply_relocations_add(pi, section,
1011 relsec, symtab);
1012 else if (relsec->sh_type == SHT_REL)
1013 ret = arch_kexec_apply_relocations(pi, section,
1014 relsec, symtab);
1015 if (ret)
1016 return ret;
1017 }
1018
1019 return 0;
1020}
1021
1022/*
1023 * kexec_load_purgatory - Load and relocate the purgatory object.
1024 * @image: Image to add the purgatory to.
1025 * @kbuf: Memory parameters to use.
1026 *
1027 * Allocates the memory needed for image->purgatory_info.sechdrs and
1028 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1029 * to free the memory after use.
1030 *
1031 * Return: 0 on success, negative errno on error.
1032 */
1033int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1034{
1035 struct purgatory_info *pi = &image->purgatory_info;
1036 int ret;
1037
1038 if (kexec_purgatory_size <= 0)
1039 return -EINVAL;
1040
1041 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1042
1043 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1044 if (ret)
1045 return ret;
1046
1047 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1048 if (ret)
1049 goto out_free_kbuf;
1050
1051 ret = kexec_apply_relocations(image);
1052 if (ret)
1053 goto out;
1054
1055 return 0;
1056out:
1057 vfree(pi->sechdrs);
1058 pi->sechdrs = NULL;
1059out_free_kbuf:
1060 vfree(pi->purgatory_buf);
1061 pi->purgatory_buf = NULL;
1062 return ret;
1063}
1064
1065/*
1066 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1067 * @pi: Purgatory to search in.
1068 * @name: Name of the symbol.
1069 *
1070 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1071 */
1072static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1073 const char *name)
1074{
1075 const Elf_Shdr *sechdrs;
1076 const Elf_Ehdr *ehdr;
1077 const Elf_Sym *syms;
1078 const char *strtab;
1079 int i, k;
1080
1081 if (!pi->ehdr)
1082 return NULL;
1083
1084 ehdr = pi->ehdr;
1085 sechdrs = (void *)ehdr + ehdr->e_shoff;
1086
1087 for (i = 0; i < ehdr->e_shnum; i++) {
1088 if (sechdrs[i].sh_type != SHT_SYMTAB)
1089 continue;
1090
1091 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1092 /* Invalid strtab section number */
1093 continue;
1094 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1095 syms = (void *)ehdr + sechdrs[i].sh_offset;
1096
1097 /* Go through symbols for a match */
1098 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1099 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1100 continue;
1101
1102 if (strcmp(strtab + syms[k].st_name, name) != 0)
1103 continue;
1104
1105 if (syms[k].st_shndx == SHN_UNDEF ||
1106 syms[k].st_shndx >= ehdr->e_shnum) {
1107 pr_debug("Symbol: %s has bad section index %d.\n",
1108 name, syms[k].st_shndx);
1109 return NULL;
1110 }
1111
1112 /* Found the symbol we are looking for */
1113 return &syms[k];
1114 }
1115 }
1116
1117 return NULL;
1118}
1119
1120void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1121{
1122 struct purgatory_info *pi = &image->purgatory_info;
1123 const Elf_Sym *sym;
1124 Elf_Shdr *sechdr;
1125
1126 sym = kexec_purgatory_find_symbol(pi, name);
1127 if (!sym)
1128 return ERR_PTR(-EINVAL);
1129
1130 sechdr = &pi->sechdrs[sym->st_shndx];
1131
1132 /*
1133 * Returns the address where symbol will finally be loaded after
1134 * kexec_load_segment()
1135 */
1136 return (void *)(sechdr->sh_addr + sym->st_value);
1137}
1138
1139/*
1140 * Get or set value of a symbol. If "get_value" is true, symbol value is
1141 * returned in buf otherwise symbol value is set based on value in buf.
1142 */
1143int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1144 void *buf, unsigned int size, bool get_value)
1145{
1146 struct purgatory_info *pi = &image->purgatory_info;
1147 const Elf_Sym *sym;
1148 Elf_Shdr *sec;
1149 char *sym_buf;
1150
1151 sym = kexec_purgatory_find_symbol(pi, name);
1152 if (!sym)
1153 return -EINVAL;
1154
1155 if (sym->st_size != size) {
1156 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1157 name, (unsigned long)sym->st_size, size);
1158 return -EINVAL;
1159 }
1160
1161 sec = pi->sechdrs + sym->st_shndx;
1162
1163 if (sec->sh_type == SHT_NOBITS) {
1164 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1165 get_value ? "get" : "set");
1166 return -EINVAL;
1167 }
1168
1169 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1170
1171 if (get_value)
1172 memcpy((void *)buf, sym_buf, size);
1173 else
1174 memcpy((void *)sym_buf, buf, size);
1175
1176 return 0;
1177}
1178#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */