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