Merge tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy...
[platform/kernel/linux-starfive.git] / kernel / kexec_file.c
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
33 static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE);
34
35 void set_kexec_sig_enforced(void)
36 {
37         sig_enforce = true;
38 }
39 #endif
40
41 static 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  */
51 int 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
68 static 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
79 int 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  */
92 void 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
128 #ifdef CONFIG_KEXEC_SIG
129 #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
130 int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
131 {
132         int ret;
133
134         ret = verify_pefile_signature(kernel, kernel_len,
135                                       VERIFY_USE_SECONDARY_KEYRING,
136                                       VERIFYING_KEXEC_PE_SIGNATURE);
137         if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
138                 ret = verify_pefile_signature(kernel, kernel_len,
139                                               VERIFY_USE_PLATFORM_KEYRING,
140                                               VERIFYING_KEXEC_PE_SIGNATURE);
141         }
142         return ret;
143 }
144 #endif
145
146 static int kexec_image_verify_sig(struct kimage *image, void *buf,
147                                   unsigned long buf_len)
148 {
149         if (!image->fops || !image->fops->verify_sig) {
150                 pr_debug("kernel loader does not support signature verification.\n");
151                 return -EKEYREJECTED;
152         }
153
154         return image->fops->verify_sig(buf, buf_len);
155 }
156
157 static int
158 kimage_validate_signature(struct kimage *image)
159 {
160         int ret;
161
162         ret = kexec_image_verify_sig(image, image->kernel_buf,
163                                      image->kernel_buf_len);
164         if (ret) {
165
166                 if (sig_enforce) {
167                         pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
168                         return ret;
169                 }
170
171                 /*
172                  * If IMA is guaranteed to appraise a signature on the kexec
173                  * image, permit it even if the kernel is otherwise locked
174                  * down.
175                  */
176                 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
177                     security_locked_down(LOCKDOWN_KEXEC))
178                         return -EPERM;
179
180                 pr_debug("kernel signature verification failed (%d).\n", ret);
181         }
182
183         return 0;
184 }
185 #endif
186
187 /*
188  * In file mode list of segments is prepared by kernel. Copy relevant
189  * data from user space, do error checking, prepare segment list
190  */
191 static int
192 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
193                              const char __user *cmdline_ptr,
194                              unsigned long cmdline_len, unsigned flags)
195 {
196         ssize_t ret;
197         void *ldata;
198
199         ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
200                                        KEXEC_FILE_SIZE_MAX, NULL,
201                                        READING_KEXEC_IMAGE);
202         if (ret < 0)
203                 return ret;
204         image->kernel_buf_len = ret;
205
206         /* Call arch image probe handlers */
207         ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
208                                             image->kernel_buf_len);
209         if (ret)
210                 goto out;
211
212 #ifdef CONFIG_KEXEC_SIG
213         ret = kimage_validate_signature(image);
214
215         if (ret)
216                 goto out;
217 #endif
218         /* It is possible that there no initramfs is being loaded */
219         if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
220                 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
221                                                KEXEC_FILE_SIZE_MAX, NULL,
222                                                READING_KEXEC_INITRAMFS);
223                 if (ret < 0)
224                         goto out;
225                 image->initrd_buf_len = ret;
226                 ret = 0;
227         }
228
229         if (cmdline_len) {
230                 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
231                 if (IS_ERR(image->cmdline_buf)) {
232                         ret = PTR_ERR(image->cmdline_buf);
233                         image->cmdline_buf = NULL;
234                         goto out;
235                 }
236
237                 image->cmdline_buf_len = cmdline_len;
238
239                 /* command line should be a string with last byte null */
240                 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
241                         ret = -EINVAL;
242                         goto out;
243                 }
244
245                 ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
246                                   image->cmdline_buf_len - 1);
247         }
248
249         /* IMA needs to pass the measurement list to the next kernel. */
250         ima_add_kexec_buffer(image);
251
252         /* Call image load handler */
253         ldata = kexec_image_load_default(image);
254
255         if (IS_ERR(ldata)) {
256                 ret = PTR_ERR(ldata);
257                 goto out;
258         }
259
260         image->image_loader_data = ldata;
261 out:
262         /* In case of error, free up all allocated memory in this function */
263         if (ret)
264                 kimage_file_post_load_cleanup(image);
265         return ret;
266 }
267
268 static int
269 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
270                        int initrd_fd, const char __user *cmdline_ptr,
271                        unsigned long cmdline_len, unsigned long flags)
272 {
273         int ret;
274         struct kimage *image;
275         bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
276
277         image = do_kimage_alloc_init();
278         if (!image)
279                 return -ENOMEM;
280
281         image->file_mode = 1;
282
283         if (kexec_on_panic) {
284                 /* Enable special crash kernel control page alloc policy. */
285                 image->control_page = crashk_res.start;
286                 image->type = KEXEC_TYPE_CRASH;
287         }
288
289         ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
290                                            cmdline_ptr, cmdline_len, flags);
291         if (ret)
292                 goto out_free_image;
293
294         ret = sanity_check_segment_list(image);
295         if (ret)
296                 goto out_free_post_load_bufs;
297
298         ret = -ENOMEM;
299         image->control_code_page = kimage_alloc_control_pages(image,
300                                            get_order(KEXEC_CONTROL_PAGE_SIZE));
301         if (!image->control_code_page) {
302                 pr_err("Could not allocate control_code_buffer\n");
303                 goto out_free_post_load_bufs;
304         }
305
306         if (!kexec_on_panic) {
307                 image->swap_page = kimage_alloc_control_pages(image, 0);
308                 if (!image->swap_page) {
309                         pr_err("Could not allocate swap buffer\n");
310                         goto out_free_control_pages;
311                 }
312         }
313
314         *rimage = image;
315         return 0;
316 out_free_control_pages:
317         kimage_free_page_list(&image->control_pages);
318 out_free_post_load_bufs:
319         kimage_file_post_load_cleanup(image);
320 out_free_image:
321         kfree(image);
322         return ret;
323 }
324
325 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
326                 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
327                 unsigned long, flags)
328 {
329         int image_type = (flags & KEXEC_FILE_ON_CRASH) ?
330                          KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT;
331         struct kimage **dest_image, *image;
332         int ret = 0, i;
333
334         /* We only trust the superuser with rebooting the system. */
335         if (!kexec_load_permitted(image_type))
336                 return -EPERM;
337
338         /* Make sure we have a legal set of flags */
339         if (flags != (flags & KEXEC_FILE_FLAGS))
340                 return -EINVAL;
341
342         image = NULL;
343
344         if (!kexec_trylock())
345                 return -EBUSY;
346
347         if (image_type == KEXEC_TYPE_CRASH) {
348                 dest_image = &kexec_crash_image;
349                 if (kexec_crash_image)
350                         arch_kexec_unprotect_crashkres();
351         } else {
352                 dest_image = &kexec_image;
353         }
354
355         if (flags & KEXEC_FILE_UNLOAD)
356                 goto exchange;
357
358         /*
359          * In case of crash, new kernel gets loaded in reserved region. It is
360          * same memory where old crash kernel might be loaded. Free any
361          * current crash dump kernel before we corrupt it.
362          */
363         if (flags & KEXEC_FILE_ON_CRASH)
364                 kimage_free(xchg(&kexec_crash_image, NULL));
365
366         ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
367                                      cmdline_len, flags);
368         if (ret)
369                 goto out;
370
371         ret = machine_kexec_prepare(image);
372         if (ret)
373                 goto out;
374
375         /*
376          * Some architecture(like S390) may touch the crash memory before
377          * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
378          */
379         ret = kimage_crash_copy_vmcoreinfo(image);
380         if (ret)
381                 goto out;
382
383         ret = kexec_calculate_store_digests(image);
384         if (ret)
385                 goto out;
386
387         for (i = 0; i < image->nr_segments; i++) {
388                 struct kexec_segment *ksegment;
389
390                 ksegment = &image->segment[i];
391                 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
392                          i, ksegment->buf, ksegment->bufsz, ksegment->mem,
393                          ksegment->memsz);
394
395                 ret = kimage_load_segment(image, &image->segment[i]);
396                 if (ret)
397                         goto out;
398         }
399
400         kimage_terminate(image);
401
402         ret = machine_kexec_post_load(image);
403         if (ret)
404                 goto out;
405
406         /*
407          * Free up any temporary buffers allocated which are not needed
408          * after image has been loaded
409          */
410         kimage_file_post_load_cleanup(image);
411 exchange:
412         image = xchg(dest_image, image);
413 out:
414         if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
415                 arch_kexec_protect_crashkres();
416
417         kexec_unlock();
418         kimage_free(image);
419         return ret;
420 }
421
422 static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
423                                     struct kexec_buf *kbuf)
424 {
425         struct kimage *image = kbuf->image;
426         unsigned long temp_start, temp_end;
427
428         temp_end = min(end, kbuf->buf_max);
429         temp_start = temp_end - kbuf->memsz;
430
431         do {
432                 /* align down start */
433                 temp_start = temp_start & (~(kbuf->buf_align - 1));
434
435                 if (temp_start < start || temp_start < kbuf->buf_min)
436                         return 0;
437
438                 temp_end = temp_start + kbuf->memsz - 1;
439
440                 /*
441                  * Make sure this does not conflict with any of existing
442                  * segments
443                  */
444                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
445                         temp_start = temp_start - PAGE_SIZE;
446                         continue;
447                 }
448
449                 /* We found a suitable memory range */
450                 break;
451         } while (1);
452
453         /* If we are here, we found a suitable memory range */
454         kbuf->mem = temp_start;
455
456         /* Success, stop navigating through remaining System RAM ranges */
457         return 1;
458 }
459
460 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
461                                      struct kexec_buf *kbuf)
462 {
463         struct kimage *image = kbuf->image;
464         unsigned long temp_start, temp_end;
465
466         temp_start = max(start, kbuf->buf_min);
467
468         do {
469                 temp_start = ALIGN(temp_start, kbuf->buf_align);
470                 temp_end = temp_start + kbuf->memsz - 1;
471
472                 if (temp_end > end || temp_end > kbuf->buf_max)
473                         return 0;
474                 /*
475                  * Make sure this does not conflict with any of existing
476                  * segments
477                  */
478                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
479                         temp_start = temp_start + PAGE_SIZE;
480                         continue;
481                 }
482
483                 /* We found a suitable memory range */
484                 break;
485         } while (1);
486
487         /* If we are here, we found a suitable memory range */
488         kbuf->mem = temp_start;
489
490         /* Success, stop navigating through remaining System RAM ranges */
491         return 1;
492 }
493
494 static int locate_mem_hole_callback(struct resource *res, void *arg)
495 {
496         struct kexec_buf *kbuf = (struct kexec_buf *)arg;
497         u64 start = res->start, end = res->end;
498         unsigned long sz = end - start + 1;
499
500         /* Returning 0 will take to next memory range */
501
502         /* Don't use memory that will be detected and handled by a driver. */
503         if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
504                 return 0;
505
506         if (sz < kbuf->memsz)
507                 return 0;
508
509         if (end < kbuf->buf_min || start > kbuf->buf_max)
510                 return 0;
511
512         /*
513          * Allocate memory top down with-in ram range. Otherwise bottom up
514          * allocation.
515          */
516         if (kbuf->top_down)
517                 return locate_mem_hole_top_down(start, end, kbuf);
518         return locate_mem_hole_bottom_up(start, end, kbuf);
519 }
520
521 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
522 static int kexec_walk_memblock(struct kexec_buf *kbuf,
523                                int (*func)(struct resource *, void *))
524 {
525         int ret = 0;
526         u64 i;
527         phys_addr_t mstart, mend;
528         struct resource res = { };
529
530         if (kbuf->image->type == KEXEC_TYPE_CRASH)
531                 return func(&crashk_res, kbuf);
532
533         /*
534          * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
535          * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
536          * locate_mem_hole_callback().
537          */
538         if (kbuf->top_down) {
539                 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
540                                                 &mstart, &mend, NULL) {
541                         /*
542                          * In memblock, end points to the first byte after the
543                          * range while in kexec, end points to the last byte
544                          * in the range.
545                          */
546                         res.start = mstart;
547                         res.end = mend - 1;
548                         ret = func(&res, kbuf);
549                         if (ret)
550                                 break;
551                 }
552         } else {
553                 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
554                                         &mstart, &mend, NULL) {
555                         /*
556                          * In memblock, end points to the first byte after the
557                          * range while in kexec, end points to the last byte
558                          * in the range.
559                          */
560                         res.start = mstart;
561                         res.end = mend - 1;
562                         ret = func(&res, kbuf);
563                         if (ret)
564                                 break;
565                 }
566         }
567
568         return ret;
569 }
570 #else
571 static int kexec_walk_memblock(struct kexec_buf *kbuf,
572                                int (*func)(struct resource *, void *))
573 {
574         return 0;
575 }
576 #endif
577
578 /**
579  * kexec_walk_resources - call func(data) on free memory regions
580  * @kbuf:       Context info for the search. Also passed to @func.
581  * @func:       Function to call for each memory region.
582  *
583  * Return: The memory walk will stop when func returns a non-zero value
584  * and that value will be returned. If all free regions are visited without
585  * func returning non-zero, then zero will be returned.
586  */
587 static int kexec_walk_resources(struct kexec_buf *kbuf,
588                                 int (*func)(struct resource *, void *))
589 {
590         if (kbuf->image->type == KEXEC_TYPE_CRASH)
591                 return walk_iomem_res_desc(crashk_res.desc,
592                                            IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
593                                            crashk_res.start, crashk_res.end,
594                                            kbuf, func);
595         else
596                 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
597 }
598
599 /**
600  * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
601  * @kbuf:       Parameters for the memory search.
602  *
603  * On success, kbuf->mem will have the start address of the memory region found.
604  *
605  * Return: 0 on success, negative errno on error.
606  */
607 int kexec_locate_mem_hole(struct kexec_buf *kbuf)
608 {
609         int ret;
610
611         /* Arch knows where to place */
612         if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
613                 return 0;
614
615         if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
616                 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
617         else
618                 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
619
620         return ret == 1 ? 0 : -EADDRNOTAVAIL;
621 }
622
623 /**
624  * kexec_add_buffer - place a buffer in a kexec segment
625  * @kbuf:       Buffer contents and memory parameters.
626  *
627  * This function assumes that kexec_lock is held.
628  * On successful return, @kbuf->mem will have the physical address of
629  * the buffer in memory.
630  *
631  * Return: 0 on success, negative errno on error.
632  */
633 int kexec_add_buffer(struct kexec_buf *kbuf)
634 {
635         struct kexec_segment *ksegment;
636         int ret;
637
638         /* Currently adding segment this way is allowed only in file mode */
639         if (!kbuf->image->file_mode)
640                 return -EINVAL;
641
642         if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
643                 return -EINVAL;
644
645         /*
646          * Make sure we are not trying to add buffer after allocating
647          * control pages. All segments need to be placed first before
648          * any control pages are allocated. As control page allocation
649          * logic goes through list of segments to make sure there are
650          * no destination overlaps.
651          */
652         if (!list_empty(&kbuf->image->control_pages)) {
653                 WARN_ON(1);
654                 return -EINVAL;
655         }
656
657         /* Ensure minimum alignment needed for segments. */
658         kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
659         kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
660
661         /* Walk the RAM ranges and allocate a suitable range for the buffer */
662         ret = arch_kexec_locate_mem_hole(kbuf);
663         if (ret)
664                 return ret;
665
666         /* Found a suitable memory range */
667         ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
668         ksegment->kbuf = kbuf->buffer;
669         ksegment->bufsz = kbuf->bufsz;
670         ksegment->mem = kbuf->mem;
671         ksegment->memsz = kbuf->memsz;
672         kbuf->image->nr_segments++;
673         return 0;
674 }
675
676 /* Calculate and store the digest of segments */
677 static int kexec_calculate_store_digests(struct kimage *image)
678 {
679         struct crypto_shash *tfm;
680         struct shash_desc *desc;
681         int ret = 0, i, j, zero_buf_sz, sha_region_sz;
682         size_t desc_size, nullsz;
683         char *digest;
684         void *zero_buf;
685         struct kexec_sha_region *sha_regions;
686         struct purgatory_info *pi = &image->purgatory_info;
687
688         if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY))
689                 return 0;
690
691         zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
692         zero_buf_sz = PAGE_SIZE;
693
694         tfm = crypto_alloc_shash("sha256", 0, 0);
695         if (IS_ERR(tfm)) {
696                 ret = PTR_ERR(tfm);
697                 goto out;
698         }
699
700         desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
701         desc = kzalloc(desc_size, GFP_KERNEL);
702         if (!desc) {
703                 ret = -ENOMEM;
704                 goto out_free_tfm;
705         }
706
707         sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
708         sha_regions = vzalloc(sha_region_sz);
709         if (!sha_regions) {
710                 ret = -ENOMEM;
711                 goto out_free_desc;
712         }
713
714         desc->tfm   = tfm;
715
716         ret = crypto_shash_init(desc);
717         if (ret < 0)
718                 goto out_free_sha_regions;
719
720         digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
721         if (!digest) {
722                 ret = -ENOMEM;
723                 goto out_free_sha_regions;
724         }
725
726         for (j = i = 0; i < image->nr_segments; i++) {
727                 struct kexec_segment *ksegment;
728
729 #ifdef CONFIG_CRASH_HOTPLUG
730                 /* Exclude elfcorehdr segment to allow future changes via hotplug */
731                 if (j == image->elfcorehdr_index)
732                         continue;
733 #endif
734
735                 ksegment = &image->segment[i];
736                 /*
737                  * Skip purgatory as it will be modified once we put digest
738                  * info in purgatory.
739                  */
740                 if (ksegment->kbuf == pi->purgatory_buf)
741                         continue;
742
743                 ret = crypto_shash_update(desc, ksegment->kbuf,
744                                           ksegment->bufsz);
745                 if (ret)
746                         break;
747
748                 /*
749                  * Assume rest of the buffer is filled with zero and
750                  * update digest accordingly.
751                  */
752                 nullsz = ksegment->memsz - ksegment->bufsz;
753                 while (nullsz) {
754                         unsigned long bytes = nullsz;
755
756                         if (bytes > zero_buf_sz)
757                                 bytes = zero_buf_sz;
758                         ret = crypto_shash_update(desc, zero_buf, bytes);
759                         if (ret)
760                                 break;
761                         nullsz -= bytes;
762                 }
763
764                 if (ret)
765                         break;
766
767                 sha_regions[j].start = ksegment->mem;
768                 sha_regions[j].len = ksegment->memsz;
769                 j++;
770         }
771
772         if (!ret) {
773                 ret = crypto_shash_final(desc, digest);
774                 if (ret)
775                         goto out_free_digest;
776                 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
777                                                      sha_regions, sha_region_sz, 0);
778                 if (ret)
779                         goto out_free_digest;
780
781                 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
782                                                      digest, SHA256_DIGEST_SIZE, 0);
783                 if (ret)
784                         goto out_free_digest;
785         }
786
787 out_free_digest:
788         kfree(digest);
789 out_free_sha_regions:
790         vfree(sha_regions);
791 out_free_desc:
792         kfree(desc);
793 out_free_tfm:
794         kfree(tfm);
795 out:
796         return ret;
797 }
798
799 #ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
800 /*
801  * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
802  * @pi:         Purgatory to be loaded.
803  * @kbuf:       Buffer to setup.
804  *
805  * Allocates the memory needed for the buffer. Caller is responsible to free
806  * the memory after use.
807  *
808  * Return: 0 on success, negative errno on error.
809  */
810 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
811                                       struct kexec_buf *kbuf)
812 {
813         const Elf_Shdr *sechdrs;
814         unsigned long bss_align;
815         unsigned long bss_sz;
816         unsigned long align;
817         int i, ret;
818
819         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
820         kbuf->buf_align = bss_align = 1;
821         kbuf->bufsz = bss_sz = 0;
822
823         for (i = 0; i < pi->ehdr->e_shnum; i++) {
824                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
825                         continue;
826
827                 align = sechdrs[i].sh_addralign;
828                 if (sechdrs[i].sh_type != SHT_NOBITS) {
829                         if (kbuf->buf_align < align)
830                                 kbuf->buf_align = align;
831                         kbuf->bufsz = ALIGN(kbuf->bufsz, align);
832                         kbuf->bufsz += sechdrs[i].sh_size;
833                 } else {
834                         if (bss_align < align)
835                                 bss_align = align;
836                         bss_sz = ALIGN(bss_sz, align);
837                         bss_sz += sechdrs[i].sh_size;
838                 }
839         }
840         kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
841         kbuf->memsz = kbuf->bufsz + bss_sz;
842         if (kbuf->buf_align < bss_align)
843                 kbuf->buf_align = bss_align;
844
845         kbuf->buffer = vzalloc(kbuf->bufsz);
846         if (!kbuf->buffer)
847                 return -ENOMEM;
848         pi->purgatory_buf = kbuf->buffer;
849
850         ret = kexec_add_buffer(kbuf);
851         if (ret)
852                 goto out;
853
854         return 0;
855 out:
856         vfree(pi->purgatory_buf);
857         pi->purgatory_buf = NULL;
858         return ret;
859 }
860
861 /*
862  * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
863  * @pi:         Purgatory to be loaded.
864  * @kbuf:       Buffer prepared to store purgatory.
865  *
866  * Allocates the memory needed for the buffer. Caller is responsible to free
867  * the memory after use.
868  *
869  * Return: 0 on success, negative errno on error.
870  */
871 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
872                                          struct kexec_buf *kbuf)
873 {
874         unsigned long bss_addr;
875         unsigned long offset;
876         size_t sechdrs_size;
877         Elf_Shdr *sechdrs;
878         int i;
879
880         /*
881          * The section headers in kexec_purgatory are read-only. In order to
882          * have them modifiable make a temporary copy.
883          */
884         sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
885         sechdrs = vzalloc(sechdrs_size);
886         if (!sechdrs)
887                 return -ENOMEM;
888         memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
889         pi->sechdrs = sechdrs;
890
891         offset = 0;
892         bss_addr = kbuf->mem + kbuf->bufsz;
893         kbuf->image->start = pi->ehdr->e_entry;
894
895         for (i = 0; i < pi->ehdr->e_shnum; i++) {
896                 unsigned long align;
897                 void *src, *dst;
898
899                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
900                         continue;
901
902                 align = sechdrs[i].sh_addralign;
903                 if (sechdrs[i].sh_type == SHT_NOBITS) {
904                         bss_addr = ALIGN(bss_addr, align);
905                         sechdrs[i].sh_addr = bss_addr;
906                         bss_addr += sechdrs[i].sh_size;
907                         continue;
908                 }
909
910                 offset = ALIGN(offset, align);
911
912                 /*
913                  * Check if the segment contains the entry point, if so,
914                  * calculate the value of image->start based on it.
915                  * If the compiler has produced more than one .text section
916                  * (Eg: .text.hot), they are generally after the main .text
917                  * section, and they shall not be used to calculate
918                  * image->start. So do not re-calculate image->start if it
919                  * is not set to the initial value, and warn the user so they
920                  * have a chance to fix their purgatory's linker script.
921                  */
922                 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
923                     pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
924                     pi->ehdr->e_entry < (sechdrs[i].sh_addr
925                                          + sechdrs[i].sh_size) &&
926                     !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
927                         kbuf->image->start -= sechdrs[i].sh_addr;
928                         kbuf->image->start += kbuf->mem + offset;
929                 }
930
931                 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
932                 dst = pi->purgatory_buf + offset;
933                 memcpy(dst, src, sechdrs[i].sh_size);
934
935                 sechdrs[i].sh_addr = kbuf->mem + offset;
936                 sechdrs[i].sh_offset = offset;
937                 offset += sechdrs[i].sh_size;
938         }
939
940         return 0;
941 }
942
943 static int kexec_apply_relocations(struct kimage *image)
944 {
945         int i, ret;
946         struct purgatory_info *pi = &image->purgatory_info;
947         const Elf_Shdr *sechdrs;
948
949         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
950
951         for (i = 0; i < pi->ehdr->e_shnum; i++) {
952                 const Elf_Shdr *relsec;
953                 const Elf_Shdr *symtab;
954                 Elf_Shdr *section;
955
956                 relsec = sechdrs + i;
957
958                 if (relsec->sh_type != SHT_RELA &&
959                     relsec->sh_type != SHT_REL)
960                         continue;
961
962                 /*
963                  * For section of type SHT_RELA/SHT_REL,
964                  * ->sh_link contains section header index of associated
965                  * symbol table. And ->sh_info contains section header
966                  * index of section to which relocations apply.
967                  */
968                 if (relsec->sh_info >= pi->ehdr->e_shnum ||
969                     relsec->sh_link >= pi->ehdr->e_shnum)
970                         return -ENOEXEC;
971
972                 section = pi->sechdrs + relsec->sh_info;
973                 symtab = sechdrs + relsec->sh_link;
974
975                 if (!(section->sh_flags & SHF_ALLOC))
976                         continue;
977
978                 /*
979                  * symtab->sh_link contain section header index of associated
980                  * string table.
981                  */
982                 if (symtab->sh_link >= pi->ehdr->e_shnum)
983                         /* Invalid section number? */
984                         continue;
985
986                 /*
987                  * Respective architecture needs to provide support for applying
988                  * relocations of type SHT_RELA/SHT_REL.
989                  */
990                 if (relsec->sh_type == SHT_RELA)
991                         ret = arch_kexec_apply_relocations_add(pi, section,
992                                                                relsec, symtab);
993                 else if (relsec->sh_type == SHT_REL)
994                         ret = arch_kexec_apply_relocations(pi, section,
995                                                            relsec, symtab);
996                 if (ret)
997                         return ret;
998         }
999
1000         return 0;
1001 }
1002
1003 /*
1004  * kexec_load_purgatory - Load and relocate the purgatory object.
1005  * @image:      Image to add the purgatory to.
1006  * @kbuf:       Memory parameters to use.
1007  *
1008  * Allocates the memory needed for image->purgatory_info.sechdrs and
1009  * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
1010  * to free the memory after use.
1011  *
1012  * Return: 0 on success, negative errno on error.
1013  */
1014 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
1015 {
1016         struct purgatory_info *pi = &image->purgatory_info;
1017         int ret;
1018
1019         if (kexec_purgatory_size <= 0)
1020                 return -EINVAL;
1021
1022         pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
1023
1024         ret = kexec_purgatory_setup_kbuf(pi, kbuf);
1025         if (ret)
1026                 return ret;
1027
1028         ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
1029         if (ret)
1030                 goto out_free_kbuf;
1031
1032         ret = kexec_apply_relocations(image);
1033         if (ret)
1034                 goto out;
1035
1036         return 0;
1037 out:
1038         vfree(pi->sechdrs);
1039         pi->sechdrs = NULL;
1040 out_free_kbuf:
1041         vfree(pi->purgatory_buf);
1042         pi->purgatory_buf = NULL;
1043         return ret;
1044 }
1045
1046 /*
1047  * kexec_purgatory_find_symbol - find a symbol in the purgatory
1048  * @pi:         Purgatory to search in.
1049  * @name:       Name of the symbol.
1050  *
1051  * Return: pointer to symbol in read-only symtab on success, NULL on error.
1052  */
1053 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1054                                                   const char *name)
1055 {
1056         const Elf_Shdr *sechdrs;
1057         const Elf_Ehdr *ehdr;
1058         const Elf_Sym *syms;
1059         const char *strtab;
1060         int i, k;
1061
1062         if (!pi->ehdr)
1063                 return NULL;
1064
1065         ehdr = pi->ehdr;
1066         sechdrs = (void *)ehdr + ehdr->e_shoff;
1067
1068         for (i = 0; i < ehdr->e_shnum; i++) {
1069                 if (sechdrs[i].sh_type != SHT_SYMTAB)
1070                         continue;
1071
1072                 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1073                         /* Invalid strtab section number */
1074                         continue;
1075                 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1076                 syms = (void *)ehdr + sechdrs[i].sh_offset;
1077
1078                 /* Go through symbols for a match */
1079                 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1080                         if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1081                                 continue;
1082
1083                         if (strcmp(strtab + syms[k].st_name, name) != 0)
1084                                 continue;
1085
1086                         if (syms[k].st_shndx == SHN_UNDEF ||
1087                             syms[k].st_shndx >= ehdr->e_shnum) {
1088                                 pr_debug("Symbol: %s has bad section index %d.\n",
1089                                                 name, syms[k].st_shndx);
1090                                 return NULL;
1091                         }
1092
1093                         /* Found the symbol we are looking for */
1094                         return &syms[k];
1095                 }
1096         }
1097
1098         return NULL;
1099 }
1100
1101 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1102 {
1103         struct purgatory_info *pi = &image->purgatory_info;
1104         const Elf_Sym *sym;
1105         Elf_Shdr *sechdr;
1106
1107         sym = kexec_purgatory_find_symbol(pi, name);
1108         if (!sym)
1109                 return ERR_PTR(-EINVAL);
1110
1111         sechdr = &pi->sechdrs[sym->st_shndx];
1112
1113         /*
1114          * Returns the address where symbol will finally be loaded after
1115          * kexec_load_segment()
1116          */
1117         return (void *)(sechdr->sh_addr + sym->st_value);
1118 }
1119
1120 /*
1121  * Get or set value of a symbol. If "get_value" is true, symbol value is
1122  * returned in buf otherwise symbol value is set based on value in buf.
1123  */
1124 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1125                                    void *buf, unsigned int size, bool get_value)
1126 {
1127         struct purgatory_info *pi = &image->purgatory_info;
1128         const Elf_Sym *sym;
1129         Elf_Shdr *sec;
1130         char *sym_buf;
1131
1132         sym = kexec_purgatory_find_symbol(pi, name);
1133         if (!sym)
1134                 return -EINVAL;
1135
1136         if (sym->st_size != size) {
1137                 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1138                        name, (unsigned long)sym->st_size, size);
1139                 return -EINVAL;
1140         }
1141
1142         sec = pi->sechdrs + sym->st_shndx;
1143
1144         if (sec->sh_type == SHT_NOBITS) {
1145                 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1146                        get_value ? "get" : "set");
1147                 return -EINVAL;
1148         }
1149
1150         sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1151
1152         if (get_value)
1153                 memcpy((void *)buf, sym_buf, size);
1154         else
1155                 memcpy((void *)sym_buf, buf, size);
1156
1157         return 0;
1158 }
1159 #endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */