GNU Linux-libre 5.4.200-gnu1
[releases.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/sha.h>
24 #include <linux/elf.h>
25 #include <linux/elfcore.h>
26 #include <linux/kernel.h>
27 #include <linux/syscalls.h>
28 #include <linux/vmalloc.h>
29 #include "kexec_internal.h"
30
31 static int kexec_calculate_store_digests(struct kimage *image);
32
33 /*
34  * Currently this is the only default function that is exported as some
35  * architectures need it to do additional handlings.
36  * In the future, other default functions may be exported too if required.
37  */
38 int kexec_image_probe_default(struct kimage *image, void *buf,
39                               unsigned long buf_len)
40 {
41         const struct kexec_file_ops * const *fops;
42         int ret = -ENOEXEC;
43
44         for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
45                 ret = (*fops)->probe(buf, buf_len);
46                 if (!ret) {
47                         image->fops = *fops;
48                         return ret;
49                 }
50         }
51
52         return ret;
53 }
54
55 /* Architectures can provide this probe function */
56 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
57                                          unsigned long buf_len)
58 {
59         return kexec_image_probe_default(image, buf, buf_len);
60 }
61
62 static void *kexec_image_load_default(struct kimage *image)
63 {
64         if (!image->fops || !image->fops->load)
65                 return ERR_PTR(-ENOEXEC);
66
67         return image->fops->load(image, image->kernel_buf,
68                                  image->kernel_buf_len, image->initrd_buf,
69                                  image->initrd_buf_len, image->cmdline_buf,
70                                  image->cmdline_buf_len);
71 }
72
73 void * __weak arch_kexec_kernel_image_load(struct kimage *image)
74 {
75         return kexec_image_load_default(image);
76 }
77
78 int kexec_image_post_load_cleanup_default(struct kimage *image)
79 {
80         if (!image->fops || !image->fops->cleanup)
81                 return 0;
82
83         return image->fops->cleanup(image->image_loader_data);
84 }
85
86 int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
87 {
88         return kexec_image_post_load_cleanup_default(image);
89 }
90
91 #ifdef CONFIG_KEXEC_SIG
92 static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
93                                           unsigned long buf_len)
94 {
95         if (!image->fops || !image->fops->verify_sig) {
96                 pr_debug("kernel loader does not support signature verification.\n");
97                 return -EKEYREJECTED;
98         }
99
100         return image->fops->verify_sig(buf, buf_len);
101 }
102
103 int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
104                                         unsigned long buf_len)
105 {
106         return kexec_image_verify_sig_default(image, buf, buf_len);
107 }
108 #endif
109
110 /*
111  * arch_kexec_apply_relocations_add - apply relocations of type RELA
112  * @pi:         Purgatory to be relocated.
113  * @section:    Section relocations applying to.
114  * @relsec:     Section containing RELAs.
115  * @symtab:     Corresponding symtab.
116  *
117  * Return: 0 on success, negative errno on error.
118  */
119 int __weak
120 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
121                                  const Elf_Shdr *relsec, const Elf_Shdr *symtab)
122 {
123         pr_err("RELA relocation unsupported.\n");
124         return -ENOEXEC;
125 }
126
127 /*
128  * arch_kexec_apply_relocations - apply relocations of type REL
129  * @pi:         Purgatory to be relocated.
130  * @section:    Section relocations applying to.
131  * @relsec:     Section containing RELs.
132  * @symtab:     Corresponding symtab.
133  *
134  * Return: 0 on success, negative errno on error.
135  */
136 int __weak
137 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
138                              const Elf_Shdr *relsec, const Elf_Shdr *symtab)
139 {
140         pr_err("REL relocation unsupported.\n");
141         return -ENOEXEC;
142 }
143
144 /*
145  * Free up memory used by kernel, initrd, and command line. This is temporary
146  * memory allocation which is not needed any more after these buffers have
147  * been loaded into separate segments and have been copied elsewhere.
148  */
149 void kimage_file_post_load_cleanup(struct kimage *image)
150 {
151         struct purgatory_info *pi = &image->purgatory_info;
152
153         vfree(image->kernel_buf);
154         image->kernel_buf = NULL;
155
156         vfree(image->initrd_buf);
157         image->initrd_buf = NULL;
158
159         kfree(image->cmdline_buf);
160         image->cmdline_buf = NULL;
161
162         vfree(pi->purgatory_buf);
163         pi->purgatory_buf = NULL;
164
165         vfree(pi->sechdrs);
166         pi->sechdrs = NULL;
167
168 #ifdef CONFIG_IMA_KEXEC
169         vfree(image->ima_buffer);
170         image->ima_buffer = NULL;
171 #endif /* CONFIG_IMA_KEXEC */
172
173         /* See if architecture has anything to cleanup post load */
174         arch_kimage_file_post_load_cleanup(image);
175
176         /*
177          * Above call should have called into bootloader to free up
178          * any data stored in kimage->image_loader_data. It should
179          * be ok now to free it up.
180          */
181         kfree(image->image_loader_data);
182         image->image_loader_data = NULL;
183 }
184
185 #ifdef CONFIG_KEXEC_SIG
186 static int
187 kimage_validate_signature(struct kimage *image)
188 {
189         const char *reason;
190         int ret;
191
192         ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
193                                            image->kernel_buf_len);
194         switch (ret) {
195         case 0:
196                 break;
197
198                 /* Certain verification errors are non-fatal if we're not
199                  * checking errors, provided we aren't mandating that there
200                  * must be a valid signature.
201                  */
202         case -ENODATA:
203                 reason = "kexec of unsigned image";
204                 goto decide;
205         case -ENOPKG:
206                 reason = "kexec of image with unsupported crypto";
207                 goto decide;
208         case -ENOKEY:
209                 reason = "kexec of image with unavailable key";
210         decide:
211                 if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
212                         pr_notice("%s rejected\n", reason);
213                         return ret;
214                 }
215
216                 /* If IMA is guaranteed to appraise a signature on the kexec
217                  * image, permit it even if the kernel is otherwise locked
218                  * down.
219                  */
220                 if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
221                     security_locked_down(LOCKDOWN_KEXEC))
222                         return -EPERM;
223
224                 return 0;
225
226                 /* All other errors are fatal, including nomem, unparseable
227                  * signatures and signature check failures - even if signatures
228                  * aren't required.
229                  */
230         default:
231                 pr_notice("kernel signature verification failed (%d).\n", ret);
232         }
233
234         return ret;
235 }
236 #endif
237
238 /*
239  * In file mode list of segments is prepared by kernel. Copy relevant
240  * data from user space, do error checking, prepare segment list
241  */
242 static int
243 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
244                              const char __user *cmdline_ptr,
245                              unsigned long cmdline_len, unsigned flags)
246 {
247         int ret;
248         void *ldata;
249         loff_t size;
250
251         ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
252                                        &size, INT_MAX, READING_KEXEC_IMAGE);
253         if (ret)
254                 return ret;
255         image->kernel_buf_len = size;
256
257         /* Call arch image probe handlers */
258         ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
259                                             image->kernel_buf_len);
260         if (ret)
261                 goto out;
262
263 #ifdef CONFIG_KEXEC_SIG
264         ret = kimage_validate_signature(image);
265
266         if (ret)
267                 goto out;
268 #endif
269         /* It is possible that there no initramfs is being loaded */
270         if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
271                 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
272                                                &size, INT_MAX,
273                                                READING_KEXEC_INITRAMFS);
274                 if (ret)
275                         goto out;
276                 image->initrd_buf_len = size;
277         }
278
279         if (cmdline_len) {
280                 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
281                 if (IS_ERR(image->cmdline_buf)) {
282                         ret = PTR_ERR(image->cmdline_buf);
283                         image->cmdline_buf = NULL;
284                         goto out;
285                 }
286
287                 image->cmdline_buf_len = cmdline_len;
288
289                 /* command line should be a string with last byte null */
290                 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
291                         ret = -EINVAL;
292                         goto out;
293                 }
294
295                 ima_kexec_cmdline(image->cmdline_buf,
296                                   image->cmdline_buf_len - 1);
297         }
298
299         /* IMA needs to pass the measurement list to the next kernel. */
300         ima_add_kexec_buffer(image);
301
302         /* Call arch image load handlers */
303         ldata = arch_kexec_kernel_image_load(image);
304
305         if (IS_ERR(ldata)) {
306                 ret = PTR_ERR(ldata);
307                 goto out;
308         }
309
310         image->image_loader_data = ldata;
311 out:
312         /* In case of error, free up all allocated memory in this function */
313         if (ret)
314                 kimage_file_post_load_cleanup(image);
315         return ret;
316 }
317
318 static int
319 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
320                        int initrd_fd, const char __user *cmdline_ptr,
321                        unsigned long cmdline_len, unsigned long flags)
322 {
323         int ret;
324         struct kimage *image;
325         bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
326
327         image = do_kimage_alloc_init();
328         if (!image)
329                 return -ENOMEM;
330
331         image->file_mode = 1;
332
333         if (kexec_on_panic) {
334                 /* Enable special crash kernel control page alloc policy. */
335                 image->control_page = crashk_res.start;
336                 image->type = KEXEC_TYPE_CRASH;
337         }
338
339         ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
340                                            cmdline_ptr, cmdline_len, flags);
341         if (ret)
342                 goto out_free_image;
343
344         ret = sanity_check_segment_list(image);
345         if (ret)
346                 goto out_free_post_load_bufs;
347
348         ret = -ENOMEM;
349         image->control_code_page = kimage_alloc_control_pages(image,
350                                            get_order(KEXEC_CONTROL_PAGE_SIZE));
351         if (!image->control_code_page) {
352                 pr_err("Could not allocate control_code_buffer\n");
353                 goto out_free_post_load_bufs;
354         }
355
356         if (!kexec_on_panic) {
357                 image->swap_page = kimage_alloc_control_pages(image, 0);
358                 if (!image->swap_page) {
359                         pr_err("Could not allocate swap buffer\n");
360                         goto out_free_control_pages;
361                 }
362         }
363
364         *rimage = image;
365         return 0;
366 out_free_control_pages:
367         kimage_free_page_list(&image->control_pages);
368 out_free_post_load_bufs:
369         kimage_file_post_load_cleanup(image);
370 out_free_image:
371         kfree(image);
372         return ret;
373 }
374
375 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
376                 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
377                 unsigned long, flags)
378 {
379         int ret = 0, i;
380         struct kimage **dest_image, *image;
381
382         /* We only trust the superuser with rebooting the system. */
383         if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
384                 return -EPERM;
385
386         /* Make sure we have a legal set of flags */
387         if (flags != (flags & KEXEC_FILE_FLAGS))
388                 return -EINVAL;
389
390         image = NULL;
391
392         if (!mutex_trylock(&kexec_mutex))
393                 return -EBUSY;
394
395         dest_image = &kexec_image;
396         if (flags & KEXEC_FILE_ON_CRASH) {
397                 dest_image = &kexec_crash_image;
398                 if (kexec_crash_image)
399                         arch_kexec_unprotect_crashkres();
400         }
401
402         if (flags & KEXEC_FILE_UNLOAD)
403                 goto exchange;
404
405         /*
406          * In case of crash, new kernel gets loaded in reserved region. It is
407          * same memory where old crash kernel might be loaded. Free any
408          * current crash dump kernel before we corrupt it.
409          */
410         if (flags & KEXEC_FILE_ON_CRASH)
411                 kimage_free(xchg(&kexec_crash_image, NULL));
412
413         ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
414                                      cmdline_len, flags);
415         if (ret)
416                 goto out;
417
418         ret = machine_kexec_prepare(image);
419         if (ret)
420                 goto out;
421
422         /*
423          * Some architecture(like S390) may touch the crash memory before
424          * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
425          */
426         ret = kimage_crash_copy_vmcoreinfo(image);
427         if (ret)
428                 goto out;
429
430         ret = kexec_calculate_store_digests(image);
431         if (ret)
432                 goto out;
433
434         for (i = 0; i < image->nr_segments; i++) {
435                 struct kexec_segment *ksegment;
436
437                 ksegment = &image->segment[i];
438                 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
439                          i, ksegment->buf, ksegment->bufsz, ksegment->mem,
440                          ksegment->memsz);
441
442                 ret = kimage_load_segment(image, &image->segment[i]);
443                 if (ret)
444                         goto out;
445         }
446
447         kimage_terminate(image);
448
449         /*
450          * Free up any temporary buffers allocated which are not needed
451          * after image has been loaded
452          */
453         kimage_file_post_load_cleanup(image);
454 exchange:
455         image = xchg(dest_image, image);
456 out:
457         if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
458                 arch_kexec_protect_crashkres();
459
460         mutex_unlock(&kexec_mutex);
461         kimage_free(image);
462         return ret;
463 }
464
465 static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
466                                     struct kexec_buf *kbuf)
467 {
468         struct kimage *image = kbuf->image;
469         unsigned long temp_start, temp_end;
470
471         temp_end = min(end, kbuf->buf_max);
472         temp_start = temp_end - kbuf->memsz;
473
474         do {
475                 /* align down start */
476                 temp_start = temp_start & (~(kbuf->buf_align - 1));
477
478                 if (temp_start < start || temp_start < kbuf->buf_min)
479                         return 0;
480
481                 temp_end = temp_start + kbuf->memsz - 1;
482
483                 /*
484                  * Make sure this does not conflict with any of existing
485                  * segments
486                  */
487                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
488                         temp_start = temp_start - PAGE_SIZE;
489                         continue;
490                 }
491
492                 /* We found a suitable memory range */
493                 break;
494         } while (1);
495
496         /* If we are here, we found a suitable memory range */
497         kbuf->mem = temp_start;
498
499         /* Success, stop navigating through remaining System RAM ranges */
500         return 1;
501 }
502
503 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
504                                      struct kexec_buf *kbuf)
505 {
506         struct kimage *image = kbuf->image;
507         unsigned long temp_start, temp_end;
508
509         temp_start = max(start, kbuf->buf_min);
510
511         do {
512                 temp_start = ALIGN(temp_start, kbuf->buf_align);
513                 temp_end = temp_start + kbuf->memsz - 1;
514
515                 if (temp_end > end || temp_end > kbuf->buf_max)
516                         return 0;
517                 /*
518                  * Make sure this does not conflict with any of existing
519                  * segments
520                  */
521                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
522                         temp_start = temp_start + PAGE_SIZE;
523                         continue;
524                 }
525
526                 /* We found a suitable memory range */
527                 break;
528         } while (1);
529
530         /* If we are here, we found a suitable memory range */
531         kbuf->mem = temp_start;
532
533         /* Success, stop navigating through remaining System RAM ranges */
534         return 1;
535 }
536
537 static int locate_mem_hole_callback(struct resource *res, void *arg)
538 {
539         struct kexec_buf *kbuf = (struct kexec_buf *)arg;
540         u64 start = res->start, end = res->end;
541         unsigned long sz = end - start + 1;
542
543         /* Returning 0 will take to next memory range */
544         if (sz < kbuf->memsz)
545                 return 0;
546
547         if (end < kbuf->buf_min || start > kbuf->buf_max)
548                 return 0;
549
550         /*
551          * Allocate memory top down with-in ram range. Otherwise bottom up
552          * allocation.
553          */
554         if (kbuf->top_down)
555                 return locate_mem_hole_top_down(start, end, kbuf);
556         return locate_mem_hole_bottom_up(start, end, kbuf);
557 }
558
559 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
560 static int kexec_walk_memblock(struct kexec_buf *kbuf,
561                                int (*func)(struct resource *, void *))
562 {
563         int ret = 0;
564         u64 i;
565         phys_addr_t mstart, mend;
566         struct resource res = { };
567
568         if (kbuf->image->type == KEXEC_TYPE_CRASH)
569                 return func(&crashk_res, kbuf);
570
571         if (kbuf->top_down) {
572                 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
573                                                 &mstart, &mend, NULL) {
574                         /*
575                          * In memblock, end points to the first byte after the
576                          * range while in kexec, end points to the last byte
577                          * in the range.
578                          */
579                         res.start = mstart;
580                         res.end = mend - 1;
581                         ret = func(&res, kbuf);
582                         if (ret)
583                                 break;
584                 }
585         } else {
586                 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
587                                         &mstart, &mend, NULL) {
588                         /*
589                          * In memblock, end points to the first byte after the
590                          * range while in kexec, end points to the last byte
591                          * in the range.
592                          */
593                         res.start = mstart;
594                         res.end = mend - 1;
595                         ret = func(&res, kbuf);
596                         if (ret)
597                                 break;
598                 }
599         }
600
601         return ret;
602 }
603 #else
604 static int kexec_walk_memblock(struct kexec_buf *kbuf,
605                                int (*func)(struct resource *, void *))
606 {
607         return 0;
608 }
609 #endif
610
611 /**
612  * kexec_walk_resources - call func(data) on free memory regions
613  * @kbuf:       Context info for the search. Also passed to @func.
614  * @func:       Function to call for each memory region.
615  *
616  * Return: The memory walk will stop when func returns a non-zero value
617  * and that value will be returned. If all free regions are visited without
618  * func returning non-zero, then zero will be returned.
619  */
620 static int kexec_walk_resources(struct kexec_buf *kbuf,
621                                 int (*func)(struct resource *, void *))
622 {
623         if (kbuf->image->type == KEXEC_TYPE_CRASH)
624                 return walk_iomem_res_desc(crashk_res.desc,
625                                            IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
626                                            crashk_res.start, crashk_res.end,
627                                            kbuf, func);
628         else
629                 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
630 }
631
632 /**
633  * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
634  * @kbuf:       Parameters for the memory search.
635  *
636  * On success, kbuf->mem will have the start address of the memory region found.
637  *
638  * Return: 0 on success, negative errno on error.
639  */
640 int kexec_locate_mem_hole(struct kexec_buf *kbuf)
641 {
642         int ret;
643
644         /* Arch knows where to place */
645         if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
646                 return 0;
647
648         if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
649                 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
650         else
651                 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
652
653         return ret == 1 ? 0 : -EADDRNOTAVAIL;
654 }
655
656 /**
657  * kexec_add_buffer - place a buffer in a kexec segment
658  * @kbuf:       Buffer contents and memory parameters.
659  *
660  * This function assumes that kexec_mutex is held.
661  * On successful return, @kbuf->mem will have the physical address of
662  * the buffer in memory.
663  *
664  * Return: 0 on success, negative errno on error.
665  */
666 int kexec_add_buffer(struct kexec_buf *kbuf)
667 {
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 = 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 */
711 static 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
815 out_free_digest:
816         kfree(digest);
817 out_free_sha_regions:
818         vfree(sha_regions);
819 out_free_desc:
820         kfree(desc);
821 out_free_tfm:
822         kfree(tfm);
823 out:
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  */
838 static 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;
883 out:
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  */
899 static 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
958 static 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  */
1029 int 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;
1052 out:
1053         vfree(pi->sechdrs);
1054         pi->sechdrs = NULL;
1055 out_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  */
1068 static 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
1116 void *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  */
1139 int 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
1176 int 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;
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
1187                 if (mstart > end || mend < start)
1188                         continue;
1189
1190                 /* Truncate any area outside of range */
1191                 if (mstart < start)
1192                         mstart = start;
1193                 if (mend > end)
1194                         mend = end;
1195
1196                 /* Found completely overlapping range */
1197                 if (mstart == start && mend == end) {
1198                         mem->ranges[i].start = 0;
1199                         mem->ranges[i].end = 0;
1200                         if (i < mem->nr_ranges - 1) {
1201                                 /* Shift rest of the ranges to left */
1202                                 for (j = i; j < mem->nr_ranges - 1; j++) {
1203                                         mem->ranges[j].start =
1204                                                 mem->ranges[j+1].start;
1205                                         mem->ranges[j].end =
1206                                                         mem->ranges[j+1].end;
1207                                 }
1208                         }
1209                         mem->nr_ranges--;
1210                         return 0;
1211                 }
1212
1213                 if (mstart > start && mend < end) {
1214                         /* Split original range */
1215                         mem->ranges[i].end = mstart - 1;
1216                         temp_range.start = mend + 1;
1217                         temp_range.end = end;
1218                 } else if (mstart != start)
1219                         mem->ranges[i].end = mstart - 1;
1220                 else
1221                         mem->ranges[i].start = mend + 1;
1222                 break;
1223         }
1224
1225         /* If a split happened, add the split to array */
1226         if (!temp_range.end)
1227                 return 0;
1228
1229         /* Split happened */
1230         if (i == mem->max_nr_ranges - 1)
1231                 return -ENOMEM;
1232
1233         /* Location where new range should go */
1234         j = i + 1;
1235         if (j < mem->nr_ranges) {
1236                 /* Move over all ranges one slot towards the end */
1237                 for (i = mem->nr_ranges - 1; i >= j; i--)
1238                         mem->ranges[i + 1] = mem->ranges[i];
1239         }
1240
1241         mem->ranges[j].start = temp_range.start;
1242         mem->ranges[j].end = temp_range.end;
1243         mem->nr_ranges++;
1244         return 0;
1245 }
1246
1247 int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1248                           void **addr, unsigned long *sz)
1249 {
1250         Elf64_Ehdr *ehdr;
1251         Elf64_Phdr *phdr;
1252         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1253         unsigned char *buf;
1254         unsigned int cpu, i;
1255         unsigned long long notes_addr;
1256         unsigned long mstart, mend;
1257
1258         /* extra phdr for vmcoreinfo elf note */
1259         nr_phdr = nr_cpus + 1;
1260         nr_phdr += mem->nr_ranges;
1261
1262         /*
1263          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1264          * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1265          * I think this is required by tools like gdb. So same physical
1266          * memory will be mapped in two elf headers. One will contain kernel
1267          * text virtual addresses and other will have __va(physical) addresses.
1268          */
1269
1270         nr_phdr++;
1271         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1272         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1273
1274         buf = vzalloc(elf_sz);
1275         if (!buf)
1276                 return -ENOMEM;
1277
1278         ehdr = (Elf64_Ehdr *)buf;
1279         phdr = (Elf64_Phdr *)(ehdr + 1);
1280         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1281         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1282         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1283         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1284         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1285         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1286         ehdr->e_type = ET_CORE;
1287         ehdr->e_machine = ELF_ARCH;
1288         ehdr->e_version = EV_CURRENT;
1289         ehdr->e_phoff = sizeof(Elf64_Ehdr);
1290         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1291         ehdr->e_phentsize = sizeof(Elf64_Phdr);
1292
1293         /* Prepare one phdr of type PT_NOTE for each present cpu */
1294         for_each_present_cpu(cpu) {
1295                 phdr->p_type = PT_NOTE;
1296                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1297                 phdr->p_offset = phdr->p_paddr = notes_addr;
1298                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1299                 (ehdr->e_phnum)++;
1300                 phdr++;
1301         }
1302
1303         /* Prepare one PT_NOTE header for vmcoreinfo */
1304         phdr->p_type = PT_NOTE;
1305         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1306         phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1307         (ehdr->e_phnum)++;
1308         phdr++;
1309
1310         /* Prepare PT_LOAD type program header for kernel text region */
1311         if (kernel_map) {
1312                 phdr->p_type = PT_LOAD;
1313                 phdr->p_flags = PF_R|PF_W|PF_X;
1314                 phdr->p_vaddr = (Elf64_Addr)_text;
1315                 phdr->p_filesz = phdr->p_memsz = _end - _text;
1316                 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1317                 ehdr->e_phnum++;
1318                 phdr++;
1319         }
1320
1321         /* Go through all the ranges in mem->ranges[] and prepare phdr */
1322         for (i = 0; i < mem->nr_ranges; i++) {
1323                 mstart = mem->ranges[i].start;
1324                 mend = mem->ranges[i].end;
1325
1326                 phdr->p_type = PT_LOAD;
1327                 phdr->p_flags = PF_R|PF_W|PF_X;
1328                 phdr->p_offset  = mstart;
1329
1330                 phdr->p_paddr = mstart;
1331                 phdr->p_vaddr = (unsigned long long) __va(mstart);
1332                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1333                 phdr->p_align = 0;
1334                 ehdr->e_phnum++;
1335                 phdr++;
1336                 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",
1337                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1338                         ehdr->e_phnum, phdr->p_offset);
1339         }
1340
1341         *addr = buf;
1342         *sz = elf_sz;
1343         return 0;
1344 }