1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * kexec: kexec_file_load system call 4 * 5 * Copyright (C) 2014 Red Hat Inc. 6 * Authors: 7 * Vivek Goyal <vgoyal@redhat.com> 8 */ 9 10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 12#include <linux/capability.h> 13#include <linux/mm.h> 14#include <linux/file.h> 15#include <linux/slab.h> 16#include <linux/kexec.h> 17#include <linux/memblock.h> 18#include <linux/mutex.h> 19#include <linux/list.h> 20#include <linux/fs.h> 21#include <linux/ima.h> 22#include <crypto/hash.h> 23#include <crypto/sha2.h> 24#include <linux/elf.h> 25#include <linux/elfcore.h> 26#include <linux/kernel.h> 27#include <linux/kernel_read_file.h> 28#include <linux/syscalls.h> 29#include <linux/vmalloc.h> 30#include "kexec_internal.h" 31 32#ifdef CONFIG_KEXEC_SIG 33static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE); 34 35void set_kexec_sig_enforced(void) 36{ 37 sig_enforce = true; 38} 39#endif 40 41static int kexec_calculate_store_digests(struct kimage *image); 42 43/* Maximum size in bytes for kernel/initrd files. */ 44#define KEXEC_FILE_SIZE_MAX min_t(s64, 4LL << 30, SSIZE_MAX) 45 46/* 47 * Currently this is the only default function that is exported as some 48 * architectures need it to do additional handlings. 49 * In the future, other default functions may be exported too if required. 50 */ 51int kexec_image_probe_default(struct kimage *image, void *buf, 52 unsigned long buf_len) 53{ 54 const struct kexec_file_ops * const *fops; 55 int ret = -ENOEXEC; 56 57 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) { 58 ret = (*fops)->probe(buf, buf_len); 59 if (!ret) { 60 image->fops = *fops; 61 return ret; 62 } 63 } 64 65 return ret; 66} 67 68static void *kexec_image_load_default(struct kimage *image) 69{ 70 if (!image->fops || !image->fops->load) 71 return ERR_PTR(-ENOEXEC); 72 73 return image->fops->load(image, image->kernel_buf, 74 image->kernel_buf_len, image->initrd_buf, 75 image->initrd_buf_len, image->cmdline_buf, 76 image->cmdline_buf_len); 77} 78 79int kexec_image_post_load_cleanup_default(struct kimage *image) 80{ 81 if (!image->fops || !image->fops->cleanup) 82 return 0; 83 84 return image->fops->cleanup(image->image_loader_data); 85} 86 87/* 88 * Free up memory used by kernel, initrd, and command line. This is temporary 89 * memory allocation which is not needed any more after these buffers have 90 * been loaded into separate segments and have been copied elsewhere. 91 */ 92void kimage_file_post_load_cleanup(struct kimage *image) 93{ 94 struct purgatory_info *pi = &image->purgatory_info; 95 96 vfree(image->kernel_buf); 97 image->kernel_buf = NULL; 98 99 vfree(image->initrd_buf); 100 image->initrd_buf = NULL; 101 102 kfree(image->cmdline_buf); 103 image->cmdline_buf = NULL; 104 105 vfree(pi->purgatory_buf); 106 pi->purgatory_buf = NULL; 107 108 vfree(pi->sechdrs); 109 pi->sechdrs = NULL; 110 111#ifdef CONFIG_IMA_KEXEC 112 vfree(image->ima_buffer); 113 image->ima_buffer = NULL; 114#endif /* CONFIG_IMA_KEXEC */ 115 116 /* See if architecture has anything to cleanup post load */ 117 arch_kimage_file_post_load_cleanup(image); 118 119 /* 120 * Above call should have called into bootloader to free up 121 * any data stored in kimage->image_loader_data. It should 122 * be ok now to free it up. 123 */ 124 kfree(image->image_loader_data); 125 image->image_loader_data = NULL; 126 127 kexec_file_dbg_print = false; 128} 129 130#ifdef CONFIG_KEXEC_SIG 131#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION 132int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len) 133{ 134 int ret; 135 136 ret = verify_pefile_signature(kernel, kernel_len, 137 VERIFY_USE_SECONDARY_KEYRING, 138 VERIFYING_KEXEC_PE_SIGNATURE); 139 if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) { 140 ret = verify_pefile_signature(kernel, kernel_len, 141 VERIFY_USE_PLATFORM_KEYRING, 142 VERIFYING_KEXEC_PE_SIGNATURE); 143 } 144 return ret; 145} 146#endif 147 148static int kexec_image_verify_sig(struct kimage *image, void *buf, 149 unsigned long buf_len) 150{ 151 if (!image->fops || !image->fops->verify_sig) { 152 pr_debug("kernel loader does not support signature verification.\n"); 153 return -EKEYREJECTED; 154 } 155 156 return image->fops->verify_sig(buf, buf_len); 157} 158 159static int 160kimage_validate_signature(struct kimage *image) 161{ 162 int ret; 163 164 ret = kexec_image_verify_sig(image, image->kernel_buf, 165 image->kernel_buf_len); 166 if (ret) { 167 168 if (sig_enforce) { 169 pr_notice("Enforced kernel signature verification failed (%d).\n", ret); 170 return ret; 171 } 172 173 /* 174 * If IMA is guaranteed to appraise a signature on the kexec 175 * image, permit it even if the kernel is otherwise locked 176 * down. 177 */ 178 if (!ima_appraise_signature(READING_KEXEC_IMAGE) && 179 security_locked_down(LOCKDOWN_KEXEC)) 180 return -EPERM; 181 182 pr_debug("kernel signature verification failed (%d).\n", ret); 183 } 184 185 return 0; 186} 187#endif 188 189/* 190 * In file mode list of segments is prepared by kernel. Copy relevant 191 * data from user space, do error checking, prepare segment list 192 */ 193static int 194kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, 195 const char __user *cmdline_ptr, 196 unsigned long cmdline_len, unsigned flags) 197{ 198 ssize_t ret; 199 void *ldata; 200 201 ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf, 202 KEXEC_FILE_SIZE_MAX, NULL, 203 READING_KEXEC_IMAGE); 204 if (ret < 0) 205 return ret; 206 image->kernel_buf_len = ret; 207 kexec_dprintk("kernel: %p kernel_size: %#lx\n", 208 image->kernel_buf, image->kernel_buf_len); 209 210 /* Call arch image probe handlers */ 211 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, 212 image->kernel_buf_len); 213 if (ret) 214 goto out; 215 216#ifdef CONFIG_KEXEC_SIG 217 ret = kimage_validate_signature(image); 218 219 if (ret) 220 goto out; 221#endif 222 /* It is possible that there no initramfs is being loaded */ 223 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { 224 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf, 225 KEXEC_FILE_SIZE_MAX, NULL, 226 READING_KEXEC_INITRAMFS); 227 if (ret < 0) 228 goto out; 229 image->initrd_buf_len = ret; 230 ret = 0; 231 } 232 233 if (cmdline_len) { 234 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len); 235 if (IS_ERR(image->cmdline_buf)) { 236 ret = PTR_ERR(image->cmdline_buf); 237 image->cmdline_buf = NULL; 238 goto out; 239 } 240 241 image->cmdline_buf_len = cmdline_len; 242 243 /* command line should be a string with last byte null */ 244 if (image->cmdline_buf[cmdline_len - 1] != '\0') { 245 ret = -EINVAL; 246 goto out; 247 } 248 249 ima_kexec_cmdline(kernel_fd, image->cmdline_buf, 250 image->cmdline_buf_len - 1); 251 } 252 253 /* IMA needs to pass the measurement list to the next kernel. */ 254 ima_add_kexec_buffer(image); 255 256 /* Call image load handler */ 257 ldata = kexec_image_load_default(image); 258 259 if (IS_ERR(ldata)) { 260 ret = PTR_ERR(ldata); 261 goto out; 262 } 263 264 image->image_loader_data = ldata; 265out: 266 /* In case of error, free up all allocated memory in this function */ 267 if (ret) 268 kimage_file_post_load_cleanup(image); 269 return ret; 270} 271 272static int 273kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, 274 int initrd_fd, const char __user *cmdline_ptr, 275 unsigned long cmdline_len, unsigned long flags) 276{ 277 int ret; 278 struct kimage *image; 279 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; 280 281 image = do_kimage_alloc_init(); 282 if (!image) 283 return -ENOMEM; 284 285 kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG); 286 image->file_mode = 1; 287 288#ifdef CONFIG_CRASH_DUMP 289 if (kexec_on_panic) { 290 /* Enable special crash kernel control page alloc policy. */ 291 image->control_page = crashk_res.start; 292 image->type = KEXEC_TYPE_CRASH; 293 } 294#endif 295 296 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, 297 cmdline_ptr, cmdline_len, flags); 298 if (ret) 299 goto out_free_image; 300 301 ret = sanity_check_segment_list(image); 302 if (ret) 303 goto out_free_post_load_bufs; 304 305 ret = -ENOMEM; 306 image->control_code_page = kimage_alloc_control_pages(image, 307 get_order(KEXEC_CONTROL_PAGE_SIZE)); 308 if (!image->control_code_page) { 309 pr_err("Could not allocate control_code_buffer\n"); 310 goto out_free_post_load_bufs; 311 } 312 313 if (!kexec_on_panic) { 314 image->swap_page = kimage_alloc_control_pages(image, 0); 315 if (!image->swap_page) { 316 pr_err("Could not allocate swap buffer\n"); 317 goto out_free_control_pages; 318 } 319 } 320 321 *rimage = image; 322 return 0; 323out_free_control_pages: 324 kimage_free_page_list(&image->control_pages); 325out_free_post_load_bufs: 326 kimage_file_post_load_cleanup(image); 327out_free_image: 328 kfree(image); 329 return ret; 330} 331 332SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, 333 unsigned long, cmdline_len, const char __user *, cmdline_ptr, 334 unsigned long, flags) 335{ 336 int image_type = (flags & KEXEC_FILE_ON_CRASH) ? 337 KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT; 338 struct kimage **dest_image, *image; 339 int ret = 0, i; 340 341 /* We only trust the superuser with rebooting the system. */ 342 if (!kexec_load_permitted(image_type)) 343 return -EPERM; 344 345 /* Make sure we have a legal set of flags */ 346 if (flags != (flags & KEXEC_FILE_FLAGS)) 347 return -EINVAL; 348 349 image = NULL; 350 351 if (!kexec_trylock()) 352 return -EBUSY; 353 354#ifdef CONFIG_CRASH_DUMP 355 if (image_type == KEXEC_TYPE_CRASH) { 356 dest_image = &kexec_crash_image; 357 if (kexec_crash_image) 358 arch_kexec_unprotect_crashkres(); 359 } else 360#endif 361 dest_image = &kexec_image; 362 363 if (flags & KEXEC_FILE_UNLOAD) 364 goto exchange; 365 366 /* 367 * In case of crash, new kernel gets loaded in reserved region. It is 368 * same memory where old crash kernel might be loaded. Free any 369 * current crash dump kernel before we corrupt it. 370 */ 371 if (flags & KEXEC_FILE_ON_CRASH) 372 kimage_free(xchg(&kexec_crash_image, NULL)); 373 374 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, 375 cmdline_len, flags); 376 if (ret) 377 goto out; 378 379 ret = machine_kexec_prepare(image); 380 if (ret) 381 goto out; 382 383 /* 384 * Some architecture(like S390) may touch the crash memory before 385 * machine_kexec_prepare(), we must copy vmcoreinfo data after it. 386 */ 387 ret = kimage_crash_copy_vmcoreinfo(image); 388 if (ret) 389 goto out; 390 391 ret = kexec_calculate_store_digests(image); 392 if (ret) 393 goto out; 394 395 kexec_dprintk("nr_segments = %lu\n", image->nr_segments); 396 for (i = 0; i < image->nr_segments; i++) { 397 struct kexec_segment *ksegment; 398 399 ksegment = &image->segment[i]; 400 kexec_dprintk("segment[%d]: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", 401 i, ksegment->buf, ksegment->bufsz, ksegment->mem, 402 ksegment->memsz); 403 404 ret = kimage_load_segment(image, &image->segment[i]); 405 if (ret) 406 goto out; 407 } 408 409 kimage_terminate(image); 410 411 ret = machine_kexec_post_load(image); 412 if (ret) 413 goto out; 414 415 kexec_dprintk("kexec_file_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n", 416 image->type, image->start, image->head, flags); 417 /* 418 * Free up any temporary buffers allocated which are not needed 419 * after image has been loaded 420 */ 421 kimage_file_post_load_cleanup(image); 422exchange: 423 image = xchg(dest_image, image); 424out: 425#ifdef CONFIG_CRASH_DUMP 426 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) 427 arch_kexec_protect_crashkres(); 428#endif 429 430 kexec_unlock(); 431 kimage_free(image); 432 return ret; 433} 434 435static int locate_mem_hole_top_down(unsigned long start, unsigned long end, 436 struct kexec_buf *kbuf) 437{ 438 struct kimage *image = kbuf->image; 439 unsigned long temp_start, temp_end; 440 441 temp_end = min(end, kbuf->buf_max); 442 temp_start = temp_end - kbuf->memsz + 1; 443 444 do { 445 /* align down start */ 446 temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align); 447 448 if (temp_start < start || temp_start < kbuf->buf_min) 449 return 0; 450 451 temp_end = temp_start + kbuf->memsz - 1; 452 453 /* 454 * Make sure this does not conflict with any of existing 455 * segments 456 */ 457 if (kimage_is_destination_range(image, temp_start, temp_end)) { 458 temp_start = temp_start - PAGE_SIZE; 459 continue; 460 } 461 462 /* We found a suitable memory range */ 463 break; 464 } while (1); 465 466 /* If we are here, we found a suitable memory range */ 467 kbuf->mem = temp_start; 468 469 /* Success, stop navigating through remaining System RAM ranges */ 470 return 1; 471} 472 473static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, 474 struct kexec_buf *kbuf) 475{ 476 struct kimage *image = kbuf->image; 477 unsigned long temp_start, temp_end; 478 479 temp_start = max(start, kbuf->buf_min); 480 481 do { 482 temp_start = ALIGN(temp_start, kbuf->buf_align); 483 temp_end = temp_start + kbuf->memsz - 1; 484 485 if (temp_end > end || temp_end > kbuf->buf_max) 486 return 0; 487 /* 488 * Make sure this does not conflict with any of existing 489 * segments 490 */ 491 if (kimage_is_destination_range(image, temp_start, temp_end)) { 492 temp_start = temp_start + PAGE_SIZE; 493 continue; 494 } 495 496 /* We found a suitable memory range */ 497 break; 498 } while (1); 499 500 /* If we are here, we found a suitable memory range */ 501 kbuf->mem = temp_start; 502 503 /* Success, stop navigating through remaining System RAM ranges */ 504 return 1; 505} 506 507static int locate_mem_hole_callback(struct resource *res, void *arg) 508{ 509 struct kexec_buf *kbuf = (struct kexec_buf *)arg; 510 u64 start = res->start, end = res->end; 511 unsigned long sz = end - start + 1; 512 513 /* Returning 0 will take to next memory range */ 514 515 /* Don't use memory that will be detected and handled by a driver. */ 516 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) 517 return 0; 518 519 if (sz < kbuf->memsz) 520 return 0; 521 522 if (end < kbuf->buf_min || start > kbuf->buf_max) 523 return 0; 524 525 /* 526 * Allocate memory top down with-in ram range. Otherwise bottom up 527 * allocation. 528 */ 529 if (kbuf->top_down) 530 return locate_mem_hole_top_down(start, end, kbuf); 531 return locate_mem_hole_bottom_up(start, end, kbuf); 532} 533 534#ifdef CONFIG_ARCH_KEEP_MEMBLOCK 535static int kexec_walk_memblock(struct kexec_buf *kbuf, 536 int (*func)(struct resource *, void *)) 537{ 538 int ret = 0; 539 u64 i; 540 phys_addr_t mstart, mend; 541 struct resource res = { }; 542 543#ifdef CONFIG_CRASH_DUMP 544 if (kbuf->image->type == KEXEC_TYPE_CRASH) 545 return func(&crashk_res, kbuf); 546#endif 547 548 /* 549 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See 550 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in 551 * locate_mem_hole_callback(). 552 */ 553 if (kbuf->top_down) { 554 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE, 555 &mstart, &mend, NULL) { 556 /* 557 * In memblock, end points to the first byte after the 558 * range while in kexec, end points to the last byte 559 * in the range. 560 */ 561 res.start = mstart; 562 res.end = mend - 1; 563 ret = func(&res, kbuf); 564 if (ret) 565 break; 566 } 567 } else { 568 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, 569 &mstart, &mend, NULL) { 570 /* 571 * In memblock, end points to the first byte after the 572 * range while in kexec, end points to the last byte 573 * in the range. 574 */ 575 res.start = mstart; 576 res.end = mend - 1; 577 ret = func(&res, kbuf); 578 if (ret) 579 break; 580 } 581 } 582 583 return ret; 584} 585#else 586static int kexec_walk_memblock(struct kexec_buf *kbuf, 587 int (*func)(struct resource *, void *)) 588{ 589 return 0; 590} 591#endif 592 593/** 594 * kexec_walk_resources - call func(data) on free memory regions 595 * @kbuf: Context info for the search. Also passed to @func. 596 * @func: Function to call for each memory region. 597 * 598 * Return: The memory walk will stop when func returns a non-zero value 599 * and that value will be returned. If all free regions are visited without 600 * func returning non-zero, then zero will be returned. 601 */ 602static int kexec_walk_resources(struct kexec_buf *kbuf, 603 int (*func)(struct resource *, void *)) 604{ 605#ifdef CONFIG_CRASH_DUMP 606 if (kbuf->image->type == KEXEC_TYPE_CRASH) 607 return walk_iomem_res_desc(crashk_res.desc, 608 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, 609 crashk_res.start, crashk_res.end, 610 kbuf, func); 611#endif 612 if (kbuf->top_down) 613 return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func); 614 else 615 return walk_system_ram_res(0, ULONG_MAX, kbuf, func); 616} 617 618/** 619 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel 620 * @kbuf: Parameters for the memory search. 621 * 622 * On success, kbuf->mem will have the start address of the memory region found. 623 * 624 * Return: 0 on success, negative errno on error. 625 */ 626int kexec_locate_mem_hole(struct kexec_buf *kbuf) 627{ 628 int ret; 629 630 /* Arch knows where to place */ 631 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) 632 return 0; 633 634 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 635 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); 636 else 637 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback); 638 639 return ret == 1 ? 0 : -EADDRNOTAVAIL; 640} 641 642/** 643 * kexec_add_buffer - place a buffer in a kexec segment 644 * @kbuf: Buffer contents and memory parameters. 645 * 646 * This function assumes that kexec_lock is held. 647 * On successful return, @kbuf->mem will have the physical address of 648 * the buffer in memory. 649 * 650 * Return: 0 on success, negative errno on error. 651 */ 652int kexec_add_buffer(struct kexec_buf *kbuf) 653{ 654 struct kexec_segment *ksegment; 655 int ret; 656 657 /* Currently adding segment this way is allowed only in file mode */ 658 if (!kbuf->image->file_mode) 659 return -EINVAL; 660 661 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) 662 return -EINVAL; 663 664 /* 665 * Make sure we are not trying to add buffer after allocating 666 * control pages. All segments need to be placed first before 667 * any control pages are allocated. As control page allocation 668 * logic goes through list of segments to make sure there are 669 * no destination overlaps. 670 */ 671 if (!list_empty(&kbuf->image->control_pages)) { 672 WARN_ON(1); 673 return -EINVAL; 674 } 675 676 /* Ensure minimum alignment needed for segments. */ 677 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); 678 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); 679 680 /* Walk the RAM ranges and allocate a suitable range for the buffer */ 681 ret = arch_kexec_locate_mem_hole(kbuf); 682 if (ret) 683 return ret; 684 685 /* Found a suitable memory range */ 686 ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; 687 ksegment->kbuf = kbuf->buffer; 688 ksegment->bufsz = kbuf->bufsz; 689 ksegment->mem = kbuf->mem; 690 ksegment->memsz = kbuf->memsz; 691 kbuf->image->nr_segments++; 692 return 0; 693} 694 695/* Calculate and store the digest of segments */ 696static int kexec_calculate_store_digests(struct kimage *image) 697{ 698 struct crypto_shash *tfm; 699 struct shash_desc *desc; 700 int ret = 0, i, j, zero_buf_sz, sha_region_sz; 701 size_t desc_size, nullsz; 702 char *digest; 703 void *zero_buf; 704 struct kexec_sha_region *sha_regions; 705 struct purgatory_info *pi = &image->purgatory_info; 706 707 if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY)) 708 return 0; 709 710 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); 711 zero_buf_sz = PAGE_SIZE; 712 713 tfm = crypto_alloc_shash("sha256", 0, 0); 714 if (IS_ERR(tfm)) { 715 ret = PTR_ERR(tfm); 716 goto out; 717 } 718 719 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); 720 desc = kzalloc(desc_size, GFP_KERNEL); 721 if (!desc) { 722 ret = -ENOMEM; 723 goto out_free_tfm; 724 } 725 726 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); 727 sha_regions = vzalloc(sha_region_sz); 728 if (!sha_regions) { 729 ret = -ENOMEM; 730 goto out_free_desc; 731 } 732 733 desc->tfm = tfm; 734 735 ret = crypto_shash_init(desc); 736 if (ret < 0) 737 goto out_free_sha_regions; 738 739 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); 740 if (!digest) { 741 ret = -ENOMEM; 742 goto out_free_sha_regions; 743 } 744 745 for (j = i = 0; i < image->nr_segments; i++) { 746 struct kexec_segment *ksegment; 747 748#ifdef CONFIG_CRASH_HOTPLUG 749 /* Exclude elfcorehdr segment to allow future changes via hotplug */ 750 if (j == image->elfcorehdr_index) 751 continue; 752#endif 753 754 ksegment = &image->segment[i]; 755 /* 756 * Skip purgatory as it will be modified once we put digest 757 * info in purgatory. 758 */ 759 if (ksegment->kbuf == pi->purgatory_buf) 760 continue; 761 762 ret = crypto_shash_update(desc, ksegment->kbuf, 763 ksegment->bufsz); 764 if (ret) 765 break; 766 767 /* 768 * Assume rest of the buffer is filled with zero and 769 * update digest accordingly. 770 */ 771 nullsz = ksegment->memsz - ksegment->bufsz; 772 while (nullsz) { 773 unsigned long bytes = nullsz; 774 775 if (bytes > zero_buf_sz) 776 bytes = zero_buf_sz; 777 ret = crypto_shash_update(desc, zero_buf, bytes); 778 if (ret) 779 break; 780 nullsz -= bytes; 781 } 782 783 if (ret) 784 break; 785 786 sha_regions[j].start = ksegment->mem; 787 sha_regions[j].len = ksegment->memsz; 788 j++; 789 } 790 791 if (!ret) { 792 ret = crypto_shash_final(desc, digest); 793 if (ret) 794 goto out_free_digest; 795 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", 796 sha_regions, sha_region_sz, 0); 797 if (ret) 798 goto out_free_digest; 799 800 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", 801 digest, SHA256_DIGEST_SIZE, 0); 802 if (ret) 803 goto out_free_digest; 804 } 805 806out_free_digest: 807 kfree(digest); 808out_free_sha_regions: 809 vfree(sha_regions); 810out_free_desc: 811 kfree(desc); 812out_free_tfm: 813 kfree(tfm); 814out: 815 return ret; 816} 817 818#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY 819/* 820 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. 821 * @pi: Purgatory to be loaded. 822 * @kbuf: Buffer to setup. 823 * 824 * Allocates the memory needed for the buffer. Caller is responsible to free 825 * the memory after use. 826 * 827 * Return: 0 on success, negative errno on error. 828 */ 829static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, 830 struct kexec_buf *kbuf) 831{ 832 const Elf_Shdr *sechdrs; 833 unsigned long bss_align; 834 unsigned long bss_sz; 835 unsigned long align; 836 int i, ret; 837 838 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 839 kbuf->buf_align = bss_align = 1; 840 kbuf->bufsz = bss_sz = 0; 841 842 for (i = 0; i < pi->ehdr->e_shnum; i++) { 843 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 844 continue; 845 846 align = sechdrs[i].sh_addralign; 847 if (sechdrs[i].sh_type != SHT_NOBITS) { 848 if (kbuf->buf_align < align) 849 kbuf->buf_align = align; 850 kbuf->bufsz = ALIGN(kbuf->bufsz, align); 851 kbuf->bufsz += sechdrs[i].sh_size; 852 } else { 853 if (bss_align < align) 854 bss_align = align; 855 bss_sz = ALIGN(bss_sz, align); 856 bss_sz += sechdrs[i].sh_size; 857 } 858 } 859 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); 860 kbuf->memsz = kbuf->bufsz + bss_sz; 861 if (kbuf->buf_align < bss_align) 862 kbuf->buf_align = bss_align; 863 864 kbuf->buffer = vzalloc(kbuf->bufsz); 865 if (!kbuf->buffer) 866 return -ENOMEM; 867 pi->purgatory_buf = kbuf->buffer; 868 869 ret = kexec_add_buffer(kbuf); 870 if (ret) 871 goto out; 872 873 return 0; 874out: 875 vfree(pi->purgatory_buf); 876 pi->purgatory_buf = NULL; 877 return ret; 878} 879 880/* 881 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. 882 * @pi: Purgatory to be loaded. 883 * @kbuf: Buffer prepared to store purgatory. 884 * 885 * Allocates the memory needed for the buffer. Caller is responsible to free 886 * the memory after use. 887 * 888 * Return: 0 on success, negative errno on error. 889 */ 890static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, 891 struct kexec_buf *kbuf) 892{ 893 unsigned long bss_addr; 894 unsigned long offset; 895 size_t sechdrs_size; 896 Elf_Shdr *sechdrs; 897 int i; 898 899 /* 900 * The section headers in kexec_purgatory are read-only. In order to 901 * have them modifiable make a temporary copy. 902 */ 903 sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum); 904 sechdrs = vzalloc(sechdrs_size); 905 if (!sechdrs) 906 return -ENOMEM; 907 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size); 908 pi->sechdrs = sechdrs; 909 910 offset = 0; 911 bss_addr = kbuf->mem + kbuf->bufsz; 912 kbuf->image->start = pi->ehdr->e_entry; 913 914 for (i = 0; i < pi->ehdr->e_shnum; i++) { 915 unsigned long align; 916 void *src, *dst; 917 918 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 919 continue; 920 921 align = sechdrs[i].sh_addralign; 922 if (sechdrs[i].sh_type == SHT_NOBITS) { 923 bss_addr = ALIGN(bss_addr, align); 924 sechdrs[i].sh_addr = bss_addr; 925 bss_addr += sechdrs[i].sh_size; 926 continue; 927 } 928 929 offset = ALIGN(offset, align); 930 931 /* 932 * Check if the segment contains the entry point, if so, 933 * calculate the value of image->start based on it. 934 * If the compiler has produced more than one .text section 935 * (Eg: .text.hot), they are generally after the main .text 936 * section, and they shall not be used to calculate 937 * image->start. So do not re-calculate image->start if it 938 * is not set to the initial value, and warn the user so they 939 * have a chance to fix their purgatory's linker script. 940 */ 941 if (sechdrs[i].sh_flags & SHF_EXECINSTR && 942 pi->ehdr->e_entry >= sechdrs[i].sh_addr && 943 pi->ehdr->e_entry < (sechdrs[i].sh_addr 944 + sechdrs[i].sh_size) && 945 !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { 946 kbuf->image->start -= sechdrs[i].sh_addr; 947 kbuf->image->start += kbuf->mem + offset; 948 } 949 950 src = (void *)pi->ehdr + sechdrs[i].sh_offset; 951 dst = pi->purgatory_buf + offset; 952 memcpy(dst, src, sechdrs[i].sh_size); 953 954 sechdrs[i].sh_addr = kbuf->mem + offset; 955 sechdrs[i].sh_offset = offset; 956 offset += sechdrs[i].sh_size; 957 } 958 959 return 0; 960} 961 962static int kexec_apply_relocations(struct kimage *image) 963{ 964 int i, ret; 965 struct purgatory_info *pi = &image->purgatory_info; 966 const Elf_Shdr *sechdrs; 967 968 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 969 970 for (i = 0; i < pi->ehdr->e_shnum; i++) { 971 const Elf_Shdr *relsec; 972 const Elf_Shdr *symtab; 973 Elf_Shdr *section; 974 975 relsec = sechdrs + i; 976 977 if (relsec->sh_type != SHT_RELA && 978 relsec->sh_type != SHT_REL) 979 continue; 980 981 /* 982 * For section of type SHT_RELA/SHT_REL, 983 * ->sh_link contains section header index of associated 984 * symbol table. And ->sh_info contains section header 985 * index of section to which relocations apply. 986 */ 987 if (relsec->sh_info >= pi->ehdr->e_shnum || 988 relsec->sh_link >= pi->ehdr->e_shnum) 989 return -ENOEXEC; 990 991 section = pi->sechdrs + relsec->sh_info; 992 symtab = sechdrs + relsec->sh_link; 993 994 if (!(section->sh_flags & SHF_ALLOC)) 995 continue; 996 997 /* 998 * symtab->sh_link contain section header index of associated 999 * string table. 1000 */ 1001 if (symtab->sh_link >= pi->ehdr->e_shnum) 1002 /* Invalid section number? */ 1003 continue; 1004 1005 /* 1006 * Respective architecture needs to provide support for applying 1007 * relocations of type SHT_RELA/SHT_REL. 1008 */ 1009 if (relsec->sh_type == SHT_RELA) 1010 ret = arch_kexec_apply_relocations_add(pi, section, 1011 relsec, symtab); 1012 else if (relsec->sh_type == SHT_REL) 1013 ret = arch_kexec_apply_relocations(pi, section, 1014 relsec, symtab); 1015 if (ret) 1016 return ret; 1017 } 1018 1019 return 0; 1020} 1021 1022/* 1023 * kexec_load_purgatory - Load and relocate the purgatory object. 1024 * @image: Image to add the purgatory to. 1025 * @kbuf: Memory parameters to use. 1026 * 1027 * Allocates the memory needed for image->purgatory_info.sechdrs and 1028 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible 1029 * to free the memory after use. 1030 * 1031 * Return: 0 on success, negative errno on error. 1032 */ 1033int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) 1034{ 1035 struct purgatory_info *pi = &image->purgatory_info; 1036 int ret; 1037 1038 if (kexec_purgatory_size <= 0) 1039 return -EINVAL; 1040 1041 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; 1042 1043 ret = kexec_purgatory_setup_kbuf(pi, kbuf); 1044 if (ret) 1045 return ret; 1046 1047 ret = kexec_purgatory_setup_sechdrs(pi, kbuf); 1048 if (ret) 1049 goto out_free_kbuf; 1050 1051 ret = kexec_apply_relocations(image); 1052 if (ret) 1053 goto out; 1054 1055 return 0; 1056out: 1057 vfree(pi->sechdrs); 1058 pi->sechdrs = NULL; 1059out_free_kbuf: 1060 vfree(pi->purgatory_buf); 1061 pi->purgatory_buf = NULL; 1062 return ret; 1063} 1064 1065/* 1066 * kexec_purgatory_find_symbol - find a symbol in the purgatory 1067 * @pi: Purgatory to search in. 1068 * @name: Name of the symbol. 1069 * 1070 * Return: pointer to symbol in read-only symtab on success, NULL on error. 1071 */ 1072static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 1073 const char *name) 1074{ 1075 const Elf_Shdr *sechdrs; 1076 const Elf_Ehdr *ehdr; 1077 const Elf_Sym *syms; 1078 const char *strtab; 1079 int i, k; 1080 1081 if (!pi->ehdr) 1082 return NULL; 1083 1084 ehdr = pi->ehdr; 1085 sechdrs = (void *)ehdr + ehdr->e_shoff; 1086 1087 for (i = 0; i < ehdr->e_shnum; i++) { 1088 if (sechdrs[i].sh_type != SHT_SYMTAB) 1089 continue; 1090 1091 if (sechdrs[i].sh_link >= ehdr->e_shnum) 1092 /* Invalid strtab section number */ 1093 continue; 1094 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; 1095 syms = (void *)ehdr + sechdrs[i].sh_offset; 1096 1097 /* Go through symbols for a match */ 1098 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { 1099 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) 1100 continue; 1101 1102 if (strcmp(strtab + syms[k].st_name, name) != 0) 1103 continue; 1104 1105 if (syms[k].st_shndx == SHN_UNDEF || 1106 syms[k].st_shndx >= ehdr->e_shnum) { 1107 pr_debug("Symbol: %s has bad section index %d.\n", 1108 name, syms[k].st_shndx); 1109 return NULL; 1110 } 1111 1112 /* Found the symbol we are looking for */ 1113 return &syms[k]; 1114 } 1115 } 1116 1117 return NULL; 1118} 1119 1120void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) 1121{ 1122 struct purgatory_info *pi = &image->purgatory_info; 1123 const Elf_Sym *sym; 1124 Elf_Shdr *sechdr; 1125 1126 sym = kexec_purgatory_find_symbol(pi, name); 1127 if (!sym) 1128 return ERR_PTR(-EINVAL); 1129 1130 sechdr = &pi->sechdrs[sym->st_shndx]; 1131 1132 /* 1133 * Returns the address where symbol will finally be loaded after 1134 * kexec_load_segment() 1135 */ 1136 return (void *)(sechdr->sh_addr + sym->st_value); 1137} 1138 1139/* 1140 * Get or set value of a symbol. If "get_value" is true, symbol value is 1141 * returned in buf otherwise symbol value is set based on value in buf. 1142 */ 1143int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 1144 void *buf, unsigned int size, bool get_value) 1145{ 1146 struct purgatory_info *pi = &image->purgatory_info; 1147 const Elf_Sym *sym; 1148 Elf_Shdr *sec; 1149 char *sym_buf; 1150 1151 sym = kexec_purgatory_find_symbol(pi, name); 1152 if (!sym) 1153 return -EINVAL; 1154 1155 if (sym->st_size != size) { 1156 pr_err("symbol %s size mismatch: expected %lu actual %u\n", 1157 name, (unsigned long)sym->st_size, size); 1158 return -EINVAL; 1159 } 1160 1161 sec = pi->sechdrs + sym->st_shndx; 1162 1163 if (sec->sh_type == SHT_NOBITS) { 1164 pr_err("symbol %s is in a bss section. Cannot %s\n", name, 1165 get_value ? "get" : "set"); 1166 return -EINVAL; 1167 } 1168 1169 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; 1170 1171 if (get_value) 1172 memcpy((void *)buf, sym_buf, size); 1173 else 1174 memcpy((void *)sym_buf, buf, size); 1175 1176 return 0; 1177} 1178#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */ 1179