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