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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#ifdef CONFIG_CRASH_HOTPLUG
380 if ((flags & KEXEC_FILE_ON_CRASH) && arch_crash_hotplug_support(image, flags))
381 image->hotplug_support = 1;
382#endif
383
384 ret = machine_kexec_prepare(image);
385 if (ret)
386 goto out;
387
388 /*
389 * Some architecture(like S390) may touch the crash memory before
390 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
391 */
392 ret = kimage_crash_copy_vmcoreinfo(image);
393 if (ret)
394 goto out;
395
396 ret = kexec_calculate_store_digests(image);
397 if (ret)
398 goto out;
399
400 kexec_dprintk("nr_segments = %lu\n", image->nr_segments);
401 for (i = 0; i < image->nr_segments; i++) {
402 struct kexec_segment *ksegment;
403
404 ksegment = &image->segment[i];
405 kexec_dprintk("segment[%d]: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
406 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
407 ksegment->memsz);
408
409 ret = kimage_load_segment(image, &image->segment[i]);
410 if (ret)
411 goto out;
412 }
413
414 kimage_terminate(image);
415
416 ret = machine_kexec_post_load(image);
417 if (ret)
418 goto out;
419
420 kexec_dprintk("kexec_file_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n",
421 image->type, image->start, image->head, flags);
422 /*
423 * Free up any temporary buffers allocated which are not needed
424 * after image has been loaded
425 */
426 kimage_file_post_load_cleanup(image);
427exchange:
428 image = xchg(dest_image, image);
429out:
430#ifdef CONFIG_CRASH_DUMP
431 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
432 arch_kexec_protect_crashkres();
433#endif
434
435 kexec_unlock();
436 kimage_free(image);
437 return ret;
438}
439
440static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
441 struct kexec_buf *kbuf)
442{
443 struct kimage *image = kbuf->image;
444 unsigned long temp_start, temp_end;
445
446 temp_end = min(end, kbuf->buf_max);
447 temp_start = temp_end - kbuf->memsz + 1;
448
449 do {
450 /* align down start */
451 temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align);
452
453 if (temp_start < start || temp_start < kbuf->buf_min)
454 return 0;
455
456 temp_end = temp_start + kbuf->memsz - 1;
457
458 /*
459 * Make sure this does not conflict with any of existing
460 * segments
461 */
462 if (kimage_is_destination_range(image, temp_start, temp_end)) {
463 temp_start = temp_start - PAGE_SIZE;
464 continue;
465 }
466
467 /* We found a suitable memory range */
468 break;
469 } while (1);
470
471 /* If we are here, we found a suitable memory range */
472 kbuf->mem = temp_start;
473
474 /* Success, stop navigating through remaining System RAM ranges */
475 return 1;
476}
477
478static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
479 struct kexec_buf *kbuf)
480{
481 struct kimage *image = kbuf->image;
482 unsigned long temp_start, temp_end;
483
484 temp_start = max(start, kbuf->buf_min);
485
486 do {
487 temp_start = ALIGN(temp_start, kbuf->buf_align);
488 temp_end = temp_start + kbuf->memsz - 1;
489
490 if (temp_end > end || temp_end > kbuf->buf_max)
491 return 0;
492 /*
493 * Make sure this does not conflict with any of existing
494 * segments
495 */
496 if (kimage_is_destination_range(image, temp_start, temp_end)) {
497 temp_start = temp_start + PAGE_SIZE;
498 continue;
499 }
500
501 /* We found a suitable memory range */
502 break;
503 } while (1);
504
505 /* If we are here, we found a suitable memory range */
506 kbuf->mem = temp_start;
507
508 /* Success, stop navigating through remaining System RAM ranges */
509 return 1;
510}
511
512static int locate_mem_hole_callback(struct resource *res, void *arg)
513{
514 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
515 u64 start = res->start, end = res->end;
516 unsigned long sz = end - start + 1;
517
518 /* Returning 0 will take to next memory range */
519
520 /* Don't use memory that will be detected and handled by a driver. */
521 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
522 return 0;
523
524 if (sz < kbuf->memsz)
525 return 0;
526
527 if (end < kbuf->buf_min || start > kbuf->buf_max)
528 return 0;
529
530 /*
531 * Allocate memory top down with-in ram range. Otherwise bottom up
532 * allocation.
533 */
534 if (kbuf->top_down)
535 return locate_mem_hole_top_down(start, end, kbuf);
536 return locate_mem_hole_bottom_up(start, end, kbuf);
537}
538
539#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
540static int kexec_walk_memblock(struct kexec_buf *kbuf,
541 int (*func)(struct resource *, void *))
542{
543 int ret = 0;
544 u64 i;
545 phys_addr_t mstart, mend;
546 struct resource res = { };
547
548#ifdef CONFIG_CRASH_DUMP
549 if (kbuf->image->type == KEXEC_TYPE_CRASH)
550 return func(&crashk_res, kbuf);
551#endif
552
553 /*
554 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
555 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
556 * locate_mem_hole_callback().
557 */
558 if (kbuf->top_down) {
559 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
560 &mstart, &mend, NULL) {
561 /*
562 * In memblock, end points to the first byte after the
563 * range while in kexec, end points to the last byte
564 * in the range.
565 */
566 res.start = mstart;
567 res.end = mend - 1;
568 ret = func(&res, kbuf);
569 if (ret)
570 break;
571 }
572 } else {
573 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
574 &mstart, &mend, NULL) {
575 /*
576 * In memblock, end points to the first byte after the
577 * range while in kexec, end points to the last byte
578 * in the range.
579 */
580 res.start = mstart;
581 res.end = mend - 1;
582 ret = func(&res, kbuf);
583 if (ret)
584 break;
585 }
586 }
587
588 return ret;
589}
590#else
591static int kexec_walk_memblock(struct kexec_buf *kbuf,
592 int (*func)(struct resource *, void *))
593{
594 return 0;
595}
596#endif
597
598/**
599 * kexec_walk_resources - call func(data) on free memory regions
600 * @kbuf: Context info for the search. Also passed to @func.
601 * @func: Function to call for each memory region.
602 *
603 * Return: The memory walk will stop when func returns a non-zero value
604 * and that value will be returned. If all free regions are visited without
605 * func returning non-zero, then zero will be returned.
606 */
607static int kexec_walk_resources(struct kexec_buf *kbuf,
608 int (*func)(struct resource *, void *))
609{
610#ifdef CONFIG_CRASH_DUMP
611 if (kbuf->image->type == KEXEC_TYPE_CRASH)
612 return walk_iomem_res_desc(crashk_res.desc,
613 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
614 crashk_res.start, crashk_res.end,
615 kbuf, func);
616#endif
617 if (kbuf->top_down)
618 return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func);
619 else
620 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
621}
622
623/**
624 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
625 * @kbuf: Parameters for the memory search.
626 *
627 * On success, kbuf->mem will have the start address of the memory region found.
628 *
629 * Return: 0 on success, negative errno on error.
630 */
631int kexec_locate_mem_hole(struct kexec_buf *kbuf)
632{
633 int ret;
634
635 /* Arch knows where to place */
636 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
637 return 0;
638
639 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
640 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
641 else
642 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
643
644 return ret == 1 ? 0 : -EADDRNOTAVAIL;
645}
646
647/**
648 * kexec_add_buffer - place a buffer in a kexec segment
649 * @kbuf: Buffer contents and memory parameters.
650 *
651 * This function assumes that kexec_lock is held.
652 * On successful return, @kbuf->mem will have the physical address of
653 * the buffer in memory.
654 *
655 * Return: 0 on success, negative errno on error.
656 */
657int kexec_add_buffer(struct kexec_buf *kbuf)
658{
659 struct kexec_segment *ksegment;
660 int ret;
661
662 /* Currently adding segment this way is allowed only in file mode */
663 if (!kbuf->image->file_mode)
664 return -EINVAL;
665
666 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
667 return -EINVAL;
668
669 /*
670 * Make sure we are not trying to add buffer after allocating
671 * control pages. All segments need to be placed first before
672 * any control pages are allocated. As control page allocation
673 * logic goes through list of segments to make sure there are
674 * no destination overlaps.
675 */
676 if (!list_empty(&kbuf->image->control_pages)) {
677 WARN_ON(1);
678 return -EINVAL;
679 }
680
681 /* Ensure minimum alignment needed for segments. */
682 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
683 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
684
685 /* Walk the RAM ranges and allocate a suitable range for the buffer */
686 ret = arch_kexec_locate_mem_hole(kbuf);
687 if (ret)
688 return ret;
689
690 /* Found a suitable memory range */
691 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
692 ksegment->kbuf = kbuf->buffer;
693 ksegment->bufsz = kbuf->bufsz;
694 ksegment->mem = kbuf->mem;
695 ksegment->memsz = kbuf->memsz;
696 kbuf->image->nr_segments++;
697 return 0;
698}
699
700/* Calculate and store the digest of segments */
701static int kexec_calculate_store_digests(struct kimage *image)
702{
703 struct crypto_shash *tfm;
704 struct shash_desc *desc;
705 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
706 size_t desc_size, nullsz;
707 char *digest;
708 void *zero_buf;
709 struct kexec_sha_region *sha_regions;
710 struct purgatory_info *pi = &image->purgatory_info;
711
712 if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY))
713 return 0;
714
715 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
716 zero_buf_sz = PAGE_SIZE;
717
718 tfm = crypto_alloc_shash("sha256", 0, 0);
719 if (IS_ERR(tfm)) {
720 ret = PTR_ERR(tfm);
721 goto out;
722 }
723
724 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
725 desc = kzalloc(desc_size, GFP_KERNEL);
726 if (!desc) {
727 ret = -ENOMEM;
728 goto out_free_tfm;
729 }
730
731 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
732 sha_regions = vzalloc(sha_region_sz);
733 if (!sha_regions) {
734 ret = -ENOMEM;
735 goto out_free_desc;
736 }
737
738 desc->tfm = tfm;
739
740 ret = crypto_shash_init(desc);
741 if (ret < 0)
742 goto out_free_sha_regions;
743
744 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
745 if (!digest) {
746 ret = -ENOMEM;
747 goto out_free_sha_regions;
748 }
749
750 for (j = i = 0; i < image->nr_segments; i++) {
751 struct kexec_segment *ksegment;
752
753#ifdef CONFIG_CRASH_HOTPLUG
754 /* Exclude elfcorehdr segment to allow future changes via hotplug */
755 if (i == image->elfcorehdr_index)
756 continue;
757#endif
758
759 ksegment = &image->segment[i];
760 /*
761 * Skip purgatory as it will be modified once we put digest
762 * info in purgatory.
763 */
764 if (ksegment->kbuf == pi->purgatory_buf)
765 continue;
766
767 ret = crypto_shash_update(desc, ksegment->kbuf,
768 ksegment->bufsz);
769 if (ret)
770 break;
771
772 /*
773 * Assume rest of the buffer is filled with zero and
774 * update digest accordingly.
775 */
776 nullsz = ksegment->memsz - ksegment->bufsz;
777 while (nullsz) {
778 unsigned long bytes = nullsz;
779
780 if (bytes > zero_buf_sz)
781 bytes = zero_buf_sz;
782 ret = crypto_shash_update(desc, zero_buf, bytes);
783 if (ret)
784 break;
785 nullsz -= bytes;
786 }
787
788 if (ret)
789 break;
790
791 sha_regions[j].start = ksegment->mem;
792 sha_regions[j].len = ksegment->memsz;
793 j++;
794 }
795
796 if (!ret) {
797 ret = crypto_shash_final(desc, digest);
798 if (ret)
799 goto out_free_digest;
800 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
801 sha_regions, sha_region_sz, 0);
802 if (ret)
803 goto out_free_digest;
804
805 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
806 digest, SHA256_DIGEST_SIZE, 0);
807 if (ret)
808 goto out_free_digest;
809 }
810
811out_free_digest:
812 kfree(digest);
813out_free_sha_regions:
814 vfree(sha_regions);
815out_free_desc:
816 kfree(desc);
817out_free_tfm:
818 kfree(tfm);
819out:
820 return ret;
821}
822
823#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
824/*
825 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
826 * @pi: Purgatory to be loaded.
827 * @kbuf: Buffer to setup.
828 *
829 * Allocates the memory needed for the buffer. Caller is responsible to free
830 * the memory after use.
831 *
832 * Return: 0 on success, negative errno on error.
833 */
834static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
835 struct kexec_buf *kbuf)
836{
837 const Elf_Shdr *sechdrs;
838 unsigned long bss_align;
839 unsigned long bss_sz;
840 unsigned long align;
841 int i, ret;
842
843 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
844 kbuf->buf_align = bss_align = 1;
845 kbuf->bufsz = bss_sz = 0;
846
847 for (i = 0; i < pi->ehdr->e_shnum; i++) {
848 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
849 continue;
850
851 align = sechdrs[i].sh_addralign;
852 if (sechdrs[i].sh_type != SHT_NOBITS) {
853 if (kbuf->buf_align < align)
854 kbuf->buf_align = align;
855 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
856 kbuf->bufsz += sechdrs[i].sh_size;
857 } else {
858 if (bss_align < align)
859 bss_align = align;
860 bss_sz = ALIGN(bss_sz, align);
861 bss_sz += sechdrs[i].sh_size;
862 }
863 }
864 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
865 kbuf->memsz = kbuf->bufsz + bss_sz;
866 if (kbuf->buf_align < bss_align)
867 kbuf->buf_align = bss_align;
868
869 kbuf->buffer = vzalloc(kbuf->bufsz);
870 if (!kbuf->buffer)
871 return -ENOMEM;
872 pi->purgatory_buf = kbuf->buffer;
873
874 ret = kexec_add_buffer(kbuf);
875 if (ret)
876 goto out;
877
878 return 0;
879out:
880 vfree(pi->purgatory_buf);
881 pi->purgatory_buf = NULL;
882 return ret;
883}
884
885/*
886 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
887 * @pi: Purgatory to be loaded.
888 * @kbuf: Buffer prepared to store purgatory.
889 *
890 * Allocates the memory needed for the buffer. Caller is responsible to free
891 * the memory after use.
892 *
893 * Return: 0 on success, negative errno on error.
894 */
895static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
896 struct kexec_buf *kbuf)
897{
898 unsigned long bss_addr;
899 unsigned long offset;
900 size_t sechdrs_size;
901 Elf_Shdr *sechdrs;
902 int i;
903
904 /*
905 * The section headers in kexec_purgatory are read-only. In order to
906 * have them modifiable make a temporary copy.
907 */
908 sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
909 sechdrs = vzalloc(sechdrs_size);
910 if (!sechdrs)
911 return -ENOMEM;
912 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
913 pi->sechdrs = sechdrs;
914
915 offset = 0;
916 bss_addr = kbuf->mem + kbuf->bufsz;
917 kbuf->image->start = pi->ehdr->e_entry;
918
919 for (i = 0; i < pi->ehdr->e_shnum; i++) {
920 unsigned long align;
921 void *src, *dst;
922
923 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
924 continue;
925
926 align = sechdrs[i].sh_addralign;
927 if (sechdrs[i].sh_type == SHT_NOBITS) {
928 bss_addr = ALIGN(bss_addr, align);
929 sechdrs[i].sh_addr = bss_addr;
930 bss_addr += sechdrs[i].sh_size;
931 continue;
932 }
933
934 offset = ALIGN(offset, align);
935
936 /*
937 * Check if the segment contains the entry point, if so,
938 * calculate the value of image->start based on it.
939 * If the compiler has produced more than one .text section
940 * (Eg: .text.hot), they are generally after the main .text
941 * section, and they shall not be used to calculate
942 * image->start. So do not re-calculate image->start if it
943 * is not set to the initial value, and warn the user so they
944 * have a chance to fix their purgatory's linker script.
945 */
946 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
947 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
948 pi->ehdr->e_entry < (sechdrs[i].sh_addr
949 + sechdrs[i].sh_size) &&
950 !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
951 kbuf->image->start -= sechdrs[i].sh_addr;
952 kbuf->image->start += kbuf->mem + offset;
953 }
954
955 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
956 dst = pi->purgatory_buf + offset;
957 memcpy(dst, src, sechdrs[i].sh_size);
958
959 sechdrs[i].sh_addr = kbuf->mem + offset;
960 sechdrs[i].sh_offset = offset;
961 offset += sechdrs[i].sh_size;
962 }
963
964 return 0;
965}
966
967static int kexec_apply_relocations(struct kimage *image)
968{
969 int i, ret;
970 struct purgatory_info *pi = &image->purgatory_info;
971 const Elf_Shdr *sechdrs;
972
973 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
974
975 for (i = 0; i < pi->ehdr->e_shnum; i++) {
976 const Elf_Shdr *relsec;
977 const Elf_Shdr *symtab;
978 Elf_Shdr *section;
979
980 relsec = sechdrs + i;
981
982 if (relsec->sh_type != SHT_RELA &&
983 relsec->sh_type != SHT_REL)
984 continue;
985
986 /*
987 * For section of type SHT_RELA/SHT_REL,
988 * ->sh_link contains section header index of associated
989 * symbol table. And ->sh_info contains section header
990 * index of section to which relocations apply.
991 */
992 if (relsec->sh_info >= pi->ehdr->e_shnum ||
993 relsec->sh_link >= pi->ehdr->e_shnum)
994 return -ENOEXEC;
995
996 section = pi->sechdrs + relsec->sh_info;
997 symtab = sechdrs + relsec->sh_link;
998
999 if (!(section->sh_flags & SHF_ALLOC))
1000 continue;
1001
1002 /*
1003 * symtab->sh_link contain section header index of associated
1004 * string table.
1005 */
1006 if (symtab->sh_link >= pi->ehdr->e_shnum)
1007 /* Invalid section number? */
1008 continue;
1009
1010 /*
1011 * Respective architecture needs to provide support for applying
1012 * relocations of type SHT_RELA/SHT_REL.
1013 */
1014 if (relsec->sh_type == SHT_RELA)
1015 ret = arch_kexec_apply_relocations_add(pi, section,
1016 relsec, symtab);
1017 else if (relsec->sh_type == SHT_REL)
1018 ret = arch_kexec_apply_relocations(pi, section,
1019 relsec, symtab);
1020 if (ret)
1021 return ret;
1022 }
1023
1024 return 0;
1025}
1026
1027/*
1028 * kexec_load_purgatory - Load and relocate the purgatory object.
1029 * @image: Image to add the purgatory to.
1030 * @kbuf: Memory parameters to use.
1031 *
1032 * Allocates the memory needed for image->purgatory_info.sechdrs and
1033 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1034 * to free the memory after use.
1035 *
1036 * Return: 0 on success, negative errno on error.
1037 */
1038int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1039{
1040 struct purgatory_info *pi = &image->purgatory_info;
1041 int ret;
1042
1043 if (kexec_purgatory_size <= 0)
1044 return -EINVAL;
1045
1046 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1047
1048 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1049 if (ret)
1050 return ret;
1051
1052 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1053 if (ret)
1054 goto out_free_kbuf;
1055
1056 ret = kexec_apply_relocations(image);
1057 if (ret)
1058 goto out;
1059
1060 return 0;
1061out:
1062 vfree(pi->sechdrs);
1063 pi->sechdrs = NULL;
1064out_free_kbuf:
1065 vfree(pi->purgatory_buf);
1066 pi->purgatory_buf = NULL;
1067 return ret;
1068}
1069
1070/*
1071 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1072 * @pi: Purgatory to search in.
1073 * @name: Name of the symbol.
1074 *
1075 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1076 */
1077static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1078 const char *name)
1079{
1080 const Elf_Shdr *sechdrs;
1081 const Elf_Ehdr *ehdr;
1082 const Elf_Sym *syms;
1083 const char *strtab;
1084 int i, k;
1085
1086 if (!pi->ehdr)
1087 return NULL;
1088
1089 ehdr = pi->ehdr;
1090 sechdrs = (void *)ehdr + ehdr->e_shoff;
1091
1092 for (i = 0; i < ehdr->e_shnum; i++) {
1093 if (sechdrs[i].sh_type != SHT_SYMTAB)
1094 continue;
1095
1096 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1097 /* Invalid strtab section number */
1098 continue;
1099 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1100 syms = (void *)ehdr + sechdrs[i].sh_offset;
1101
1102 /* Go through symbols for a match */
1103 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1104 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1105 continue;
1106
1107 if (strcmp(strtab + syms[k].st_name, name) != 0)
1108 continue;
1109
1110 if (syms[k].st_shndx == SHN_UNDEF ||
1111 syms[k].st_shndx >= ehdr->e_shnum) {
1112 pr_debug("Symbol: %s has bad section index %d.\n",
1113 name, syms[k].st_shndx);
1114 return NULL;
1115 }
1116
1117 /* Found the symbol we are looking for */
1118 return &syms[k];
1119 }
1120 }
1121
1122 return NULL;
1123}
1124
1125void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1126{
1127 struct purgatory_info *pi = &image->purgatory_info;
1128 const Elf_Sym *sym;
1129 Elf_Shdr *sechdr;
1130
1131 sym = kexec_purgatory_find_symbol(pi, name);
1132 if (!sym)
1133 return ERR_PTR(-EINVAL);
1134
1135 sechdr = &pi->sechdrs[sym->st_shndx];
1136
1137 /*
1138 * Returns the address where symbol will finally be loaded after
1139 * kexec_load_segment()
1140 */
1141 return (void *)(sechdr->sh_addr + sym->st_value);
1142}
1143
1144/*
1145 * Get or set value of a symbol. If "get_value" is true, symbol value is
1146 * returned in buf otherwise symbol value is set based on value in buf.
1147 */
1148int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1149 void *buf, unsigned int size, bool get_value)
1150{
1151 struct purgatory_info *pi = &image->purgatory_info;
1152 const Elf_Sym *sym;
1153 Elf_Shdr *sec;
1154 char *sym_buf;
1155
1156 sym = kexec_purgatory_find_symbol(pi, name);
1157 if (!sym)
1158 return -EINVAL;
1159
1160 if (sym->st_size != size) {
1161 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1162 name, (unsigned long)sym->st_size, size);
1163 return -EINVAL;
1164 }
1165
1166 sec = pi->sechdrs + sym->st_shndx;
1167
1168 if (sec->sh_type == SHT_NOBITS) {
1169 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1170 get_value ? "get" : "set");
1171 return -EINVAL;
1172 }
1173
1174 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1175
1176 if (get_value)
1177 memcpy((void *)buf, sym_buf, size);
1178 else
1179 memcpy((void *)sym_buf, buf, size);
1180
1181 return 0;
1182}
1183#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */
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
32static int kexec_calculate_store_digests(struct kimage *image);
33
34/*
35 * Currently this is the only default function that is exported as some
36 * architectures need it to do additional handlings.
37 * In the future, other default functions may be exported too if required.
38 */
39int kexec_image_probe_default(struct kimage *image, void *buf,
40 unsigned long buf_len)
41{
42 const struct kexec_file_ops * const *fops;
43 int ret = -ENOEXEC;
44
45 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
46 ret = (*fops)->probe(buf, buf_len);
47 if (!ret) {
48 image->fops = *fops;
49 return ret;
50 }
51 }
52
53 return ret;
54}
55
56/* Architectures can provide this probe function */
57int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
58 unsigned long buf_len)
59{
60 return kexec_image_probe_default(image, buf, buf_len);
61}
62
63static void *kexec_image_load_default(struct kimage *image)
64{
65 if (!image->fops || !image->fops->load)
66 return ERR_PTR(-ENOEXEC);
67
68 return image->fops->load(image, image->kernel_buf,
69 image->kernel_buf_len, image->initrd_buf,
70 image->initrd_buf_len, image->cmdline_buf,
71 image->cmdline_buf_len);
72}
73
74void * __weak arch_kexec_kernel_image_load(struct kimage *image)
75{
76 return kexec_image_load_default(image);
77}
78
79int kexec_image_post_load_cleanup_default(struct kimage *image)
80{
81 if (!image->fops || !image->fops->cleanup)
82 return 0;
83
84 return image->fops->cleanup(image->image_loader_data);
85}
86
87int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
88{
89 return kexec_image_post_load_cleanup_default(image);
90}
91
92#ifdef CONFIG_KEXEC_SIG
93static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
94 unsigned long buf_len)
95{
96 if (!image->fops || !image->fops->verify_sig) {
97 pr_debug("kernel loader does not support signature verification.\n");
98 return -EKEYREJECTED;
99 }
100
101 return image->fops->verify_sig(buf, buf_len);
102}
103
104int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
105 unsigned long buf_len)
106{
107 return kexec_image_verify_sig_default(image, buf, buf_len);
108}
109#endif
110
111/*
112 * arch_kexec_apply_relocations_add - apply relocations of type RELA
113 * @pi: Purgatory to be relocated.
114 * @section: Section relocations applying to.
115 * @relsec: Section containing RELAs.
116 * @symtab: Corresponding symtab.
117 *
118 * Return: 0 on success, negative errno on error.
119 */
120int __weak
121arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
122 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
123{
124 pr_err("RELA relocation unsupported.\n");
125 return -ENOEXEC;
126}
127
128/*
129 * arch_kexec_apply_relocations - apply relocations of type REL
130 * @pi: Purgatory to be relocated.
131 * @section: Section relocations applying to.
132 * @relsec: Section containing RELs.
133 * @symtab: Corresponding symtab.
134 *
135 * Return: 0 on success, negative errno on error.
136 */
137int __weak
138arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
139 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
140{
141 pr_err("REL relocation unsupported.\n");
142 return -ENOEXEC;
143}
144
145/*
146 * Free up memory used by kernel, initrd, and command line. This is temporary
147 * memory allocation which is not needed any more after these buffers have
148 * been loaded into separate segments and have been copied elsewhere.
149 */
150void kimage_file_post_load_cleanup(struct kimage *image)
151{
152 struct purgatory_info *pi = &image->purgatory_info;
153
154 vfree(image->kernel_buf);
155 image->kernel_buf = NULL;
156
157 vfree(image->initrd_buf);
158 image->initrd_buf = NULL;
159
160 kfree(image->cmdline_buf);
161 image->cmdline_buf = NULL;
162
163 vfree(pi->purgatory_buf);
164 pi->purgatory_buf = NULL;
165
166 vfree(pi->sechdrs);
167 pi->sechdrs = NULL;
168
169#ifdef CONFIG_IMA_KEXEC
170 vfree(image->ima_buffer);
171 image->ima_buffer = NULL;
172#endif /* CONFIG_IMA_KEXEC */
173
174 /* See if architecture has anything to cleanup post load */
175 arch_kimage_file_post_load_cleanup(image);
176
177 /*
178 * Above call should have called into bootloader to free up
179 * any data stored in kimage->image_loader_data. It should
180 * be ok now to free it up.
181 */
182 kfree(image->image_loader_data);
183 image->image_loader_data = NULL;
184}
185
186#ifdef CONFIG_KEXEC_SIG
187static int
188kimage_validate_signature(struct kimage *image)
189{
190 int ret;
191
192 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
193 image->kernel_buf_len);
194 if (ret) {
195
196 if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
197 pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
198 return ret;
199 }
200
201 /*
202 * If IMA is guaranteed to appraise a signature on the kexec
203 * image, permit it even if the kernel is otherwise locked
204 * down.
205 */
206 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
207 security_locked_down(LOCKDOWN_KEXEC))
208 return -EPERM;
209
210 pr_debug("kernel signature verification failed (%d).\n", ret);
211 }
212
213 return 0;
214}
215#endif
216
217/*
218 * In file mode list of segments is prepared by kernel. Copy relevant
219 * data from user space, do error checking, prepare segment list
220 */
221static int
222kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
223 const char __user *cmdline_ptr,
224 unsigned long cmdline_len, unsigned flags)
225{
226 int ret;
227 void *ldata;
228
229 ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
230 INT_MAX, NULL, READING_KEXEC_IMAGE);
231 if (ret < 0)
232 return ret;
233 image->kernel_buf_len = ret;
234
235 /* Call arch image probe handlers */
236 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
237 image->kernel_buf_len);
238 if (ret)
239 goto out;
240
241#ifdef CONFIG_KEXEC_SIG
242 ret = kimage_validate_signature(image);
243
244 if (ret)
245 goto out;
246#endif
247 /* It is possible that there no initramfs is being loaded */
248 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
249 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
250 INT_MAX, NULL,
251 READING_KEXEC_INITRAMFS);
252 if (ret < 0)
253 goto out;
254 image->initrd_buf_len = ret;
255 ret = 0;
256 }
257
258 if (cmdline_len) {
259 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
260 if (IS_ERR(image->cmdline_buf)) {
261 ret = PTR_ERR(image->cmdline_buf);
262 image->cmdline_buf = NULL;
263 goto out;
264 }
265
266 image->cmdline_buf_len = cmdline_len;
267
268 /* command line should be a string with last byte null */
269 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
270 ret = -EINVAL;
271 goto out;
272 }
273
274 ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
275 image->cmdline_buf_len - 1);
276 }
277
278 /* IMA needs to pass the measurement list to the next kernel. */
279 ima_add_kexec_buffer(image);
280
281 /* Call arch image load handlers */
282 ldata = arch_kexec_kernel_image_load(image);
283
284 if (IS_ERR(ldata)) {
285 ret = PTR_ERR(ldata);
286 goto out;
287 }
288
289 image->image_loader_data = ldata;
290out:
291 /* In case of error, free up all allocated memory in this function */
292 if (ret)
293 kimage_file_post_load_cleanup(image);
294 return ret;
295}
296
297static int
298kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
299 int initrd_fd, const char __user *cmdline_ptr,
300 unsigned long cmdline_len, unsigned long flags)
301{
302 int ret;
303 struct kimage *image;
304 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
305
306 image = do_kimage_alloc_init();
307 if (!image)
308 return -ENOMEM;
309
310 image->file_mode = 1;
311
312 if (kexec_on_panic) {
313 /* Enable special crash kernel control page alloc policy. */
314 image->control_page = crashk_res.start;
315 image->type = KEXEC_TYPE_CRASH;
316 }
317
318 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
319 cmdline_ptr, cmdline_len, flags);
320 if (ret)
321 goto out_free_image;
322
323 ret = sanity_check_segment_list(image);
324 if (ret)
325 goto out_free_post_load_bufs;
326
327 ret = -ENOMEM;
328 image->control_code_page = kimage_alloc_control_pages(image,
329 get_order(KEXEC_CONTROL_PAGE_SIZE));
330 if (!image->control_code_page) {
331 pr_err("Could not allocate control_code_buffer\n");
332 goto out_free_post_load_bufs;
333 }
334
335 if (!kexec_on_panic) {
336 image->swap_page = kimage_alloc_control_pages(image, 0);
337 if (!image->swap_page) {
338 pr_err("Could not allocate swap buffer\n");
339 goto out_free_control_pages;
340 }
341 }
342
343 *rimage = image;
344 return 0;
345out_free_control_pages:
346 kimage_free_page_list(&image->control_pages);
347out_free_post_load_bufs:
348 kimage_file_post_load_cleanup(image);
349out_free_image:
350 kfree(image);
351 return ret;
352}
353
354SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
355 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
356 unsigned long, flags)
357{
358 int ret = 0, i;
359 struct kimage **dest_image, *image;
360
361 /* We only trust the superuser with rebooting the system. */
362 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
363 return -EPERM;
364
365 /* Make sure we have a legal set of flags */
366 if (flags != (flags & KEXEC_FILE_FLAGS))
367 return -EINVAL;
368
369 image = NULL;
370
371 if (!mutex_trylock(&kexec_mutex))
372 return -EBUSY;
373
374 dest_image = &kexec_image;
375 if (flags & KEXEC_FILE_ON_CRASH) {
376 dest_image = &kexec_crash_image;
377 if (kexec_crash_image)
378 arch_kexec_unprotect_crashkres();
379 }
380
381 if (flags & KEXEC_FILE_UNLOAD)
382 goto exchange;
383
384 /*
385 * In case of crash, new kernel gets loaded in reserved region. It is
386 * same memory where old crash kernel might be loaded. Free any
387 * current crash dump kernel before we corrupt it.
388 */
389 if (flags & KEXEC_FILE_ON_CRASH)
390 kimage_free(xchg(&kexec_crash_image, NULL));
391
392 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
393 cmdline_len, flags);
394 if (ret)
395 goto out;
396
397 ret = machine_kexec_prepare(image);
398 if (ret)
399 goto out;
400
401 /*
402 * Some architecture(like S390) may touch the crash memory before
403 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
404 */
405 ret = kimage_crash_copy_vmcoreinfo(image);
406 if (ret)
407 goto out;
408
409 ret = kexec_calculate_store_digests(image);
410 if (ret)
411 goto out;
412
413 for (i = 0; i < image->nr_segments; i++) {
414 struct kexec_segment *ksegment;
415
416 ksegment = &image->segment[i];
417 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
418 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
419 ksegment->memsz);
420
421 ret = kimage_load_segment(image, &image->segment[i]);
422 if (ret)
423 goto out;
424 }
425
426 kimage_terminate(image);
427
428 ret = machine_kexec_post_load(image);
429 if (ret)
430 goto out;
431
432 /*
433 * Free up any temporary buffers allocated which are not needed
434 * after image has been loaded
435 */
436 kimage_file_post_load_cleanup(image);
437exchange:
438 image = xchg(dest_image, image);
439out:
440 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
441 arch_kexec_protect_crashkres();
442
443 mutex_unlock(&kexec_mutex);
444 kimage_free(image);
445 return ret;
446}
447
448static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
449 struct kexec_buf *kbuf)
450{
451 struct kimage *image = kbuf->image;
452 unsigned long temp_start, temp_end;
453
454 temp_end = min(end, kbuf->buf_max);
455 temp_start = temp_end - kbuf->memsz;
456
457 do {
458 /* align down start */
459 temp_start = temp_start & (~(kbuf->buf_align - 1));
460
461 if (temp_start < start || temp_start < kbuf->buf_min)
462 return 0;
463
464 temp_end = temp_start + kbuf->memsz - 1;
465
466 /*
467 * Make sure this does not conflict with any of existing
468 * segments
469 */
470 if (kimage_is_destination_range(image, temp_start, temp_end)) {
471 temp_start = temp_start - PAGE_SIZE;
472 continue;
473 }
474
475 /* We found a suitable memory range */
476 break;
477 } while (1);
478
479 /* If we are here, we found a suitable memory range */
480 kbuf->mem = temp_start;
481
482 /* Success, stop navigating through remaining System RAM ranges */
483 return 1;
484}
485
486static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
487 struct kexec_buf *kbuf)
488{
489 struct kimage *image = kbuf->image;
490 unsigned long temp_start, temp_end;
491
492 temp_start = max(start, kbuf->buf_min);
493
494 do {
495 temp_start = ALIGN(temp_start, kbuf->buf_align);
496 temp_end = temp_start + kbuf->memsz - 1;
497
498 if (temp_end > end || temp_end > kbuf->buf_max)
499 return 0;
500 /*
501 * Make sure this does not conflict with any of existing
502 * segments
503 */
504 if (kimage_is_destination_range(image, temp_start, temp_end)) {
505 temp_start = temp_start + PAGE_SIZE;
506 continue;
507 }
508
509 /* We found a suitable memory range */
510 break;
511 } while (1);
512
513 /* If we are here, we found a suitable memory range */
514 kbuf->mem = temp_start;
515
516 /* Success, stop navigating through remaining System RAM ranges */
517 return 1;
518}
519
520static int locate_mem_hole_callback(struct resource *res, void *arg)
521{
522 struct kexec_buf *kbuf = (struct kexec_buf *)arg;
523 u64 start = res->start, end = res->end;
524 unsigned long sz = end - start + 1;
525
526 /* Returning 0 will take to next memory range */
527
528 /* Don't use memory that will be detected and handled by a driver. */
529 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
530 return 0;
531
532 if (sz < kbuf->memsz)
533 return 0;
534
535 if (end < kbuf->buf_min || start > kbuf->buf_max)
536 return 0;
537
538 /*
539 * Allocate memory top down with-in ram range. Otherwise bottom up
540 * allocation.
541 */
542 if (kbuf->top_down)
543 return locate_mem_hole_top_down(start, end, kbuf);
544 return locate_mem_hole_bottom_up(start, end, kbuf);
545}
546
547#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
548static int kexec_walk_memblock(struct kexec_buf *kbuf,
549 int (*func)(struct resource *, void *))
550{
551 int ret = 0;
552 u64 i;
553 phys_addr_t mstart, mend;
554 struct resource res = { };
555
556 if (kbuf->image->type == KEXEC_TYPE_CRASH)
557 return func(&crashk_res, kbuf);
558
559 if (kbuf->top_down) {
560 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
561 &mstart, &mend, NULL) {
562 /*
563 * In memblock, end points to the first byte after the
564 * range while in kexec, end points to the last byte
565 * in the range.
566 */
567 res.start = mstart;
568 res.end = mend - 1;
569 ret = func(&res, kbuf);
570 if (ret)
571 break;
572 }
573 } else {
574 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
575 &mstart, &mend, NULL) {
576 /*
577 * In memblock, end points to the first byte after the
578 * range while in kexec, end points to the last byte
579 * in the range.
580 */
581 res.start = mstart;
582 res.end = mend - 1;
583 ret = func(&res, kbuf);
584 if (ret)
585 break;
586 }
587 }
588
589 return ret;
590}
591#else
592static int kexec_walk_memblock(struct kexec_buf *kbuf,
593 int (*func)(struct resource *, void *))
594{
595 return 0;
596}
597#endif
598
599/**
600 * kexec_walk_resources - call func(data) on free memory regions
601 * @kbuf: Context info for the search. Also passed to @func.
602 * @func: Function to call for each memory region.
603 *
604 * Return: The memory walk will stop when func returns a non-zero value
605 * and that value will be returned. If all free regions are visited without
606 * func returning non-zero, then zero will be returned.
607 */
608static int kexec_walk_resources(struct kexec_buf *kbuf,
609 int (*func)(struct resource *, void *))
610{
611 if (kbuf->image->type == KEXEC_TYPE_CRASH)
612 return walk_iomem_res_desc(crashk_res.desc,
613 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
614 crashk_res.start, crashk_res.end,
615 kbuf, func);
616 else
617 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
618}
619
620/**
621 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
622 * @kbuf: Parameters for the memory search.
623 *
624 * On success, kbuf->mem will have the start address of the memory region found.
625 *
626 * Return: 0 on success, negative errno on error.
627 */
628int kexec_locate_mem_hole(struct kexec_buf *kbuf)
629{
630 int ret;
631
632 /* Arch knows where to place */
633 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
634 return 0;
635
636 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
637 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
638 else
639 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
640
641 return ret == 1 ? 0 : -EADDRNOTAVAIL;
642}
643
644/**
645 * arch_kexec_locate_mem_hole - Find free memory to place the segments.
646 * @kbuf: Parameters for the memory search.
647 *
648 * On success, kbuf->mem will have the start address of the memory region found.
649 *
650 * Return: 0 on success, negative errno on error.
651 */
652int __weak arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
653{
654 return kexec_locate_mem_hole(kbuf);
655}
656
657/**
658 * kexec_add_buffer - place a buffer in a kexec segment
659 * @kbuf: Buffer contents and memory parameters.
660 *
661 * This function assumes that kexec_mutex is held.
662 * On successful return, @kbuf->mem will have the physical address of
663 * the buffer in memory.
664 *
665 * Return: 0 on success, negative errno on error.
666 */
667int kexec_add_buffer(struct kexec_buf *kbuf)
668{
669 struct kexec_segment *ksegment;
670 int ret;
671
672 /* Currently adding segment this way is allowed only in file mode */
673 if (!kbuf->image->file_mode)
674 return -EINVAL;
675
676 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
677 return -EINVAL;
678
679 /*
680 * Make sure we are not trying to add buffer after allocating
681 * control pages. All segments need to be placed first before
682 * any control pages are allocated. As control page allocation
683 * logic goes through list of segments to make sure there are
684 * no destination overlaps.
685 */
686 if (!list_empty(&kbuf->image->control_pages)) {
687 WARN_ON(1);
688 return -EINVAL;
689 }
690
691 /* Ensure minimum alignment needed for segments. */
692 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
693 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
694
695 /* Walk the RAM ranges and allocate a suitable range for the buffer */
696 ret = arch_kexec_locate_mem_hole(kbuf);
697 if (ret)
698 return ret;
699
700 /* Found a suitable memory range */
701 ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
702 ksegment->kbuf = kbuf->buffer;
703 ksegment->bufsz = kbuf->bufsz;
704 ksegment->mem = kbuf->mem;
705 ksegment->memsz = kbuf->memsz;
706 kbuf->image->nr_segments++;
707 return 0;
708}
709
710/* Calculate and store the digest of segments */
711static int kexec_calculate_store_digests(struct kimage *image)
712{
713 struct crypto_shash *tfm;
714 struct shash_desc *desc;
715 int ret = 0, i, j, zero_buf_sz, sha_region_sz;
716 size_t desc_size, nullsz;
717 char *digest;
718 void *zero_buf;
719 struct kexec_sha_region *sha_regions;
720 struct purgatory_info *pi = &image->purgatory_info;
721
722 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
723 return 0;
724
725 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
726 zero_buf_sz = PAGE_SIZE;
727
728 tfm = crypto_alloc_shash("sha256", 0, 0);
729 if (IS_ERR(tfm)) {
730 ret = PTR_ERR(tfm);
731 goto out;
732 }
733
734 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
735 desc = kzalloc(desc_size, GFP_KERNEL);
736 if (!desc) {
737 ret = -ENOMEM;
738 goto out_free_tfm;
739 }
740
741 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
742 sha_regions = vzalloc(sha_region_sz);
743 if (!sha_regions) {
744 ret = -ENOMEM;
745 goto out_free_desc;
746 }
747
748 desc->tfm = tfm;
749
750 ret = crypto_shash_init(desc);
751 if (ret < 0)
752 goto out_free_sha_regions;
753
754 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
755 if (!digest) {
756 ret = -ENOMEM;
757 goto out_free_sha_regions;
758 }
759
760 for (j = i = 0; i < image->nr_segments; i++) {
761 struct kexec_segment *ksegment;
762
763 ksegment = &image->segment[i];
764 /*
765 * Skip purgatory as it will be modified once we put digest
766 * info in purgatory.
767 */
768 if (ksegment->kbuf == pi->purgatory_buf)
769 continue;
770
771 ret = crypto_shash_update(desc, ksegment->kbuf,
772 ksegment->bufsz);
773 if (ret)
774 break;
775
776 /*
777 * Assume rest of the buffer is filled with zero and
778 * update digest accordingly.
779 */
780 nullsz = ksegment->memsz - ksegment->bufsz;
781 while (nullsz) {
782 unsigned long bytes = nullsz;
783
784 if (bytes > zero_buf_sz)
785 bytes = zero_buf_sz;
786 ret = crypto_shash_update(desc, zero_buf, bytes);
787 if (ret)
788 break;
789 nullsz -= bytes;
790 }
791
792 if (ret)
793 break;
794
795 sha_regions[j].start = ksegment->mem;
796 sha_regions[j].len = ksegment->memsz;
797 j++;
798 }
799
800 if (!ret) {
801 ret = crypto_shash_final(desc, digest);
802 if (ret)
803 goto out_free_digest;
804 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
805 sha_regions, sha_region_sz, 0);
806 if (ret)
807 goto out_free_digest;
808
809 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
810 digest, SHA256_DIGEST_SIZE, 0);
811 if (ret)
812 goto out_free_digest;
813 }
814
815out_free_digest:
816 kfree(digest);
817out_free_sha_regions:
818 vfree(sha_regions);
819out_free_desc:
820 kfree(desc);
821out_free_tfm:
822 kfree(tfm);
823out:
824 return ret;
825}
826
827#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
828/*
829 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
830 * @pi: Purgatory to be loaded.
831 * @kbuf: Buffer to setup.
832 *
833 * Allocates the memory needed for the buffer. Caller is responsible to free
834 * the memory after use.
835 *
836 * Return: 0 on success, negative errno on error.
837 */
838static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
839 struct kexec_buf *kbuf)
840{
841 const Elf_Shdr *sechdrs;
842 unsigned long bss_align;
843 unsigned long bss_sz;
844 unsigned long align;
845 int i, ret;
846
847 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
848 kbuf->buf_align = bss_align = 1;
849 kbuf->bufsz = bss_sz = 0;
850
851 for (i = 0; i < pi->ehdr->e_shnum; i++) {
852 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
853 continue;
854
855 align = sechdrs[i].sh_addralign;
856 if (sechdrs[i].sh_type != SHT_NOBITS) {
857 if (kbuf->buf_align < align)
858 kbuf->buf_align = align;
859 kbuf->bufsz = ALIGN(kbuf->bufsz, align);
860 kbuf->bufsz += sechdrs[i].sh_size;
861 } else {
862 if (bss_align < align)
863 bss_align = align;
864 bss_sz = ALIGN(bss_sz, align);
865 bss_sz += sechdrs[i].sh_size;
866 }
867 }
868 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
869 kbuf->memsz = kbuf->bufsz + bss_sz;
870 if (kbuf->buf_align < bss_align)
871 kbuf->buf_align = bss_align;
872
873 kbuf->buffer = vzalloc(kbuf->bufsz);
874 if (!kbuf->buffer)
875 return -ENOMEM;
876 pi->purgatory_buf = kbuf->buffer;
877
878 ret = kexec_add_buffer(kbuf);
879 if (ret)
880 goto out;
881
882 return 0;
883out:
884 vfree(pi->purgatory_buf);
885 pi->purgatory_buf = NULL;
886 return ret;
887}
888
889/*
890 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
891 * @pi: Purgatory to be loaded.
892 * @kbuf: Buffer prepared to store purgatory.
893 *
894 * Allocates the memory needed for the buffer. Caller is responsible to free
895 * the memory after use.
896 *
897 * Return: 0 on success, negative errno on error.
898 */
899static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
900 struct kexec_buf *kbuf)
901{
902 unsigned long bss_addr;
903 unsigned long offset;
904 Elf_Shdr *sechdrs;
905 int i;
906
907 /*
908 * The section headers in kexec_purgatory are read-only. In order to
909 * have them modifiable make a temporary copy.
910 */
911 sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
912 if (!sechdrs)
913 return -ENOMEM;
914 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
915 pi->ehdr->e_shnum * sizeof(Elf_Shdr));
916 pi->sechdrs = sechdrs;
917
918 offset = 0;
919 bss_addr = kbuf->mem + kbuf->bufsz;
920 kbuf->image->start = pi->ehdr->e_entry;
921
922 for (i = 0; i < pi->ehdr->e_shnum; i++) {
923 unsigned long align;
924 void *src, *dst;
925
926 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
927 continue;
928
929 align = sechdrs[i].sh_addralign;
930 if (sechdrs[i].sh_type == SHT_NOBITS) {
931 bss_addr = ALIGN(bss_addr, align);
932 sechdrs[i].sh_addr = bss_addr;
933 bss_addr += sechdrs[i].sh_size;
934 continue;
935 }
936
937 offset = ALIGN(offset, align);
938 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
939 pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
940 pi->ehdr->e_entry < (sechdrs[i].sh_addr
941 + sechdrs[i].sh_size)) {
942 kbuf->image->start -= sechdrs[i].sh_addr;
943 kbuf->image->start += kbuf->mem + offset;
944 }
945
946 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
947 dst = pi->purgatory_buf + offset;
948 memcpy(dst, src, sechdrs[i].sh_size);
949
950 sechdrs[i].sh_addr = kbuf->mem + offset;
951 sechdrs[i].sh_offset = offset;
952 offset += sechdrs[i].sh_size;
953 }
954
955 return 0;
956}
957
958static int kexec_apply_relocations(struct kimage *image)
959{
960 int i, ret;
961 struct purgatory_info *pi = &image->purgatory_info;
962 const Elf_Shdr *sechdrs;
963
964 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
965
966 for (i = 0; i < pi->ehdr->e_shnum; i++) {
967 const Elf_Shdr *relsec;
968 const Elf_Shdr *symtab;
969 Elf_Shdr *section;
970
971 relsec = sechdrs + i;
972
973 if (relsec->sh_type != SHT_RELA &&
974 relsec->sh_type != SHT_REL)
975 continue;
976
977 /*
978 * For section of type SHT_RELA/SHT_REL,
979 * ->sh_link contains section header index of associated
980 * symbol table. And ->sh_info contains section header
981 * index of section to which relocations apply.
982 */
983 if (relsec->sh_info >= pi->ehdr->e_shnum ||
984 relsec->sh_link >= pi->ehdr->e_shnum)
985 return -ENOEXEC;
986
987 section = pi->sechdrs + relsec->sh_info;
988 symtab = sechdrs + relsec->sh_link;
989
990 if (!(section->sh_flags & SHF_ALLOC))
991 continue;
992
993 /*
994 * symtab->sh_link contain section header index of associated
995 * string table.
996 */
997 if (symtab->sh_link >= pi->ehdr->e_shnum)
998 /* Invalid section number? */
999 continue;
1000
1001 /*
1002 * Respective architecture needs to provide support for applying
1003 * relocations of type SHT_RELA/SHT_REL.
1004 */
1005 if (relsec->sh_type == SHT_RELA)
1006 ret = arch_kexec_apply_relocations_add(pi, section,
1007 relsec, symtab);
1008 else if (relsec->sh_type == SHT_REL)
1009 ret = arch_kexec_apply_relocations(pi, section,
1010 relsec, symtab);
1011 if (ret)
1012 return ret;
1013 }
1014
1015 return 0;
1016}
1017
1018/*
1019 * kexec_load_purgatory - Load and relocate the purgatory object.
1020 * @image: Image to add the purgatory to.
1021 * @kbuf: Memory parameters to use.
1022 *
1023 * Allocates the memory needed for image->purgatory_info.sechdrs and
1024 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1025 * to free the memory after use.
1026 *
1027 * Return: 0 on success, negative errno on error.
1028 */
1029int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1030{
1031 struct purgatory_info *pi = &image->purgatory_info;
1032 int ret;
1033
1034 if (kexec_purgatory_size <= 0)
1035 return -EINVAL;
1036
1037 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1038
1039 ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1040 if (ret)
1041 return ret;
1042
1043 ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1044 if (ret)
1045 goto out_free_kbuf;
1046
1047 ret = kexec_apply_relocations(image);
1048 if (ret)
1049 goto out;
1050
1051 return 0;
1052out:
1053 vfree(pi->sechdrs);
1054 pi->sechdrs = NULL;
1055out_free_kbuf:
1056 vfree(pi->purgatory_buf);
1057 pi->purgatory_buf = NULL;
1058 return ret;
1059}
1060
1061/*
1062 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1063 * @pi: Purgatory to search in.
1064 * @name: Name of the symbol.
1065 *
1066 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1067 */
1068static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1069 const char *name)
1070{
1071 const Elf_Shdr *sechdrs;
1072 const Elf_Ehdr *ehdr;
1073 const Elf_Sym *syms;
1074 const char *strtab;
1075 int i, k;
1076
1077 if (!pi->ehdr)
1078 return NULL;
1079
1080 ehdr = pi->ehdr;
1081 sechdrs = (void *)ehdr + ehdr->e_shoff;
1082
1083 for (i = 0; i < ehdr->e_shnum; i++) {
1084 if (sechdrs[i].sh_type != SHT_SYMTAB)
1085 continue;
1086
1087 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1088 /* Invalid strtab section number */
1089 continue;
1090 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1091 syms = (void *)ehdr + sechdrs[i].sh_offset;
1092
1093 /* Go through symbols for a match */
1094 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1095 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1096 continue;
1097
1098 if (strcmp(strtab + syms[k].st_name, name) != 0)
1099 continue;
1100
1101 if (syms[k].st_shndx == SHN_UNDEF ||
1102 syms[k].st_shndx >= ehdr->e_shnum) {
1103 pr_debug("Symbol: %s has bad section index %d.\n",
1104 name, syms[k].st_shndx);
1105 return NULL;
1106 }
1107
1108 /* Found the symbol we are looking for */
1109 return &syms[k];
1110 }
1111 }
1112
1113 return NULL;
1114}
1115
1116void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1117{
1118 struct purgatory_info *pi = &image->purgatory_info;
1119 const Elf_Sym *sym;
1120 Elf_Shdr *sechdr;
1121
1122 sym = kexec_purgatory_find_symbol(pi, name);
1123 if (!sym)
1124 return ERR_PTR(-EINVAL);
1125
1126 sechdr = &pi->sechdrs[sym->st_shndx];
1127
1128 /*
1129 * Returns the address where symbol will finally be loaded after
1130 * kexec_load_segment()
1131 */
1132 return (void *)(sechdr->sh_addr + sym->st_value);
1133}
1134
1135/*
1136 * Get or set value of a symbol. If "get_value" is true, symbol value is
1137 * returned in buf otherwise symbol value is set based on value in buf.
1138 */
1139int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1140 void *buf, unsigned int size, bool get_value)
1141{
1142 struct purgatory_info *pi = &image->purgatory_info;
1143 const Elf_Sym *sym;
1144 Elf_Shdr *sec;
1145 char *sym_buf;
1146
1147 sym = kexec_purgatory_find_symbol(pi, name);
1148 if (!sym)
1149 return -EINVAL;
1150
1151 if (sym->st_size != size) {
1152 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1153 name, (unsigned long)sym->st_size, size);
1154 return -EINVAL;
1155 }
1156
1157 sec = pi->sechdrs + sym->st_shndx;
1158
1159 if (sec->sh_type == SHT_NOBITS) {
1160 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1161 get_value ? "get" : "set");
1162 return -EINVAL;
1163 }
1164
1165 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1166
1167 if (get_value)
1168 memcpy((void *)buf, sym_buf, size);
1169 else
1170 memcpy((void *)sym_buf, buf, size);
1171
1172 return 0;
1173}
1174#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1175
1176int crash_exclude_mem_range(struct crash_mem *mem,
1177 unsigned long long mstart, unsigned long long mend)
1178{
1179 int i, j;
1180 unsigned long long start, end, p_start, p_end;
1181 struct crash_mem_range temp_range = {0, 0};
1182
1183 for (i = 0; i < mem->nr_ranges; i++) {
1184 start = mem->ranges[i].start;
1185 end = mem->ranges[i].end;
1186 p_start = mstart;
1187 p_end = mend;
1188
1189 if (mstart > end || mend < start)
1190 continue;
1191
1192 /* Truncate any area outside of range */
1193 if (mstart < start)
1194 p_start = start;
1195 if (mend > end)
1196 p_end = end;
1197
1198 /* Found completely overlapping range */
1199 if (p_start == start && p_end == end) {
1200 mem->ranges[i].start = 0;
1201 mem->ranges[i].end = 0;
1202 if (i < mem->nr_ranges - 1) {
1203 /* Shift rest of the ranges to left */
1204 for (j = i; j < mem->nr_ranges - 1; j++) {
1205 mem->ranges[j].start =
1206 mem->ranges[j+1].start;
1207 mem->ranges[j].end =
1208 mem->ranges[j+1].end;
1209 }
1210
1211 /*
1212 * Continue to check if there are another overlapping ranges
1213 * from the current position because of shifting the above
1214 * mem ranges.
1215 */
1216 i--;
1217 mem->nr_ranges--;
1218 continue;
1219 }
1220 mem->nr_ranges--;
1221 return 0;
1222 }
1223
1224 if (p_start > start && p_end < end) {
1225 /* Split original range */
1226 mem->ranges[i].end = p_start - 1;
1227 temp_range.start = p_end + 1;
1228 temp_range.end = end;
1229 } else if (p_start != start)
1230 mem->ranges[i].end = p_start - 1;
1231 else
1232 mem->ranges[i].start = p_end + 1;
1233 break;
1234 }
1235
1236 /* If a split happened, add the split to array */
1237 if (!temp_range.end)
1238 return 0;
1239
1240 /* Split happened */
1241 if (i == mem->max_nr_ranges - 1)
1242 return -ENOMEM;
1243
1244 /* Location where new range should go */
1245 j = i + 1;
1246 if (j < mem->nr_ranges) {
1247 /* Move over all ranges one slot towards the end */
1248 for (i = mem->nr_ranges - 1; i >= j; i--)
1249 mem->ranges[i + 1] = mem->ranges[i];
1250 }
1251
1252 mem->ranges[j].start = temp_range.start;
1253 mem->ranges[j].end = temp_range.end;
1254 mem->nr_ranges++;
1255 return 0;
1256}
1257
1258int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1259 void **addr, unsigned long *sz)
1260{
1261 Elf64_Ehdr *ehdr;
1262 Elf64_Phdr *phdr;
1263 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1264 unsigned char *buf;
1265 unsigned int cpu, i;
1266 unsigned long long notes_addr;
1267 unsigned long mstart, mend;
1268
1269 /* extra phdr for vmcoreinfo ELF note */
1270 nr_phdr = nr_cpus + 1;
1271 nr_phdr += mem->nr_ranges;
1272
1273 /*
1274 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1275 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1276 * I think this is required by tools like gdb. So same physical
1277 * memory will be mapped in two ELF headers. One will contain kernel
1278 * text virtual addresses and other will have __va(physical) addresses.
1279 */
1280
1281 nr_phdr++;
1282 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1283 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1284
1285 buf = vzalloc(elf_sz);
1286 if (!buf)
1287 return -ENOMEM;
1288
1289 ehdr = (Elf64_Ehdr *)buf;
1290 phdr = (Elf64_Phdr *)(ehdr + 1);
1291 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1292 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1293 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1294 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1295 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1296 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1297 ehdr->e_type = ET_CORE;
1298 ehdr->e_machine = ELF_ARCH;
1299 ehdr->e_version = EV_CURRENT;
1300 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1301 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1302 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1303
1304 /* Prepare one phdr of type PT_NOTE for each present CPU */
1305 for_each_present_cpu(cpu) {
1306 phdr->p_type = PT_NOTE;
1307 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1308 phdr->p_offset = phdr->p_paddr = notes_addr;
1309 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1310 (ehdr->e_phnum)++;
1311 phdr++;
1312 }
1313
1314 /* Prepare one PT_NOTE header for vmcoreinfo */
1315 phdr->p_type = PT_NOTE;
1316 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1317 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1318 (ehdr->e_phnum)++;
1319 phdr++;
1320
1321 /* Prepare PT_LOAD type program header for kernel text region */
1322 if (kernel_map) {
1323 phdr->p_type = PT_LOAD;
1324 phdr->p_flags = PF_R|PF_W|PF_X;
1325 phdr->p_vaddr = (unsigned long) _text;
1326 phdr->p_filesz = phdr->p_memsz = _end - _text;
1327 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1328 ehdr->e_phnum++;
1329 phdr++;
1330 }
1331
1332 /* Go through all the ranges in mem->ranges[] and prepare phdr */
1333 for (i = 0; i < mem->nr_ranges; i++) {
1334 mstart = mem->ranges[i].start;
1335 mend = mem->ranges[i].end;
1336
1337 phdr->p_type = PT_LOAD;
1338 phdr->p_flags = PF_R|PF_W|PF_X;
1339 phdr->p_offset = mstart;
1340
1341 phdr->p_paddr = mstart;
1342 phdr->p_vaddr = (unsigned long) __va(mstart);
1343 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1344 phdr->p_align = 0;
1345 ehdr->e_phnum++;
1346 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",
1347 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1348 ehdr->e_phnum, phdr->p_offset);
1349 phdr++;
1350 }
1351
1352 *addr = buf;
1353 *sz = elf_sz;
1354 return 0;
1355}