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#ifdef CONFIG_CRASH_HOTPLUG 380 if ((flags & KEXEC_FILE_ON_CRASH) && arch_crash_hotplug_support(image, flags)) 381 image->hotplug_support = 1; 382#endif 383 384 ret = machine_kexec_prepare(image); 385 if (ret) 386 goto out; 387 388 /* 389 * Some architecture(like S390) may touch the crash memory before 390 * machine_kexec_prepare(), we must copy vmcoreinfo data after it. 391 */ 392 ret = kimage_crash_copy_vmcoreinfo(image); 393 if (ret) 394 goto out; 395 396 ret = kexec_calculate_store_digests(image); 397 if (ret) 398 goto out; 399 400 kexec_dprintk("nr_segments = %lu\n", image->nr_segments); 401 for (i = 0; i < image->nr_segments; i++) { 402 struct kexec_segment *ksegment; 403 404 ksegment = &image->segment[i]; 405 kexec_dprintk("segment[%d]: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", 406 i, ksegment->buf, ksegment->bufsz, ksegment->mem, 407 ksegment->memsz); 408 409 ret = kimage_load_segment(image, &image->segment[i]); 410 if (ret) 411 goto out; 412 } 413 414 kimage_terminate(image); 415 416 ret = machine_kexec_post_load(image); 417 if (ret) 418 goto out; 419 420 kexec_dprintk("kexec_file_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n", 421 image->type, image->start, image->head, flags); 422 /* 423 * Free up any temporary buffers allocated which are not needed 424 * after image has been loaded 425 */ 426 kimage_file_post_load_cleanup(image); 427exchange: 428 image = xchg(dest_image, image); 429out: 430#ifdef CONFIG_CRASH_DUMP 431 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) 432 arch_kexec_protect_crashkres(); 433#endif 434 435 kexec_unlock(); 436 kimage_free(image); 437 return ret; 438} 439 440static int locate_mem_hole_top_down(unsigned long start, unsigned long end, 441 struct kexec_buf *kbuf) 442{ 443 struct kimage *image = kbuf->image; 444 unsigned long temp_start, temp_end; 445 446 temp_end = min(end, kbuf->buf_max); 447 temp_start = temp_end - kbuf->memsz + 1; 448 449 do { 450 /* align down start */ 451 temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align); 452 453 if (temp_start < start || temp_start < kbuf->buf_min) 454 return 0; 455 456 temp_end = temp_start + kbuf->memsz - 1; 457 458 /* 459 * Make sure this does not conflict with any of existing 460 * segments 461 */ 462 if (kimage_is_destination_range(image, temp_start, temp_end)) { 463 temp_start = temp_start - PAGE_SIZE; 464 continue; 465 } 466 467 /* We found a suitable memory range */ 468 break; 469 } while (1); 470 471 /* If we are here, we found a suitable memory range */ 472 kbuf->mem = temp_start; 473 474 /* Success, stop navigating through remaining System RAM ranges */ 475 return 1; 476} 477 478static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, 479 struct kexec_buf *kbuf) 480{ 481 struct kimage *image = kbuf->image; 482 unsigned long temp_start, temp_end; 483 484 temp_start = max(start, kbuf->buf_min); 485 486 do { 487 temp_start = ALIGN(temp_start, kbuf->buf_align); 488 temp_end = temp_start + kbuf->memsz - 1; 489 490 if (temp_end > end || temp_end > kbuf->buf_max) 491 return 0; 492 /* 493 * Make sure this does not conflict with any of existing 494 * segments 495 */ 496 if (kimage_is_destination_range(image, temp_start, temp_end)) { 497 temp_start = temp_start + PAGE_SIZE; 498 continue; 499 } 500 501 /* We found a suitable memory range */ 502 break; 503 } while (1); 504 505 /* If we are here, we found a suitable memory range */ 506 kbuf->mem = temp_start; 507 508 /* Success, stop navigating through remaining System RAM ranges */ 509 return 1; 510} 511 512static int locate_mem_hole_callback(struct resource *res, void *arg) 513{ 514 struct kexec_buf *kbuf = (struct kexec_buf *)arg; 515 u64 start = res->start, end = res->end; 516 unsigned long sz = end - start + 1; 517 518 /* Returning 0 will take to next memory range */ 519 520 /* Don't use memory that will be detected and handled by a driver. */ 521 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) 522 return 0; 523 524 if (sz < kbuf->memsz) 525 return 0; 526 527 if (end < kbuf->buf_min || start > kbuf->buf_max) 528 return 0; 529 530 /* 531 * Allocate memory top down with-in ram range. Otherwise bottom up 532 * allocation. 533 */ 534 if (kbuf->top_down) 535 return locate_mem_hole_top_down(start, end, kbuf); 536 return locate_mem_hole_bottom_up(start, end, kbuf); 537} 538 539#ifdef CONFIG_ARCH_KEEP_MEMBLOCK 540static int kexec_walk_memblock(struct kexec_buf *kbuf, 541 int (*func)(struct resource *, void *)) 542{ 543 int ret = 0; 544 u64 i; 545 phys_addr_t mstart, mend; 546 struct resource res = { }; 547 548#ifdef CONFIG_CRASH_DUMP 549 if (kbuf->image->type == KEXEC_TYPE_CRASH) 550 return func(&crashk_res, kbuf); 551#endif 552 553 /* 554 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See 555 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in 556 * locate_mem_hole_callback(). 557 */ 558 if (kbuf->top_down) { 559 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE, 560 &mstart, &mend, NULL) { 561 /* 562 * In memblock, end points to the first byte after the 563 * range while in kexec, end points to the last byte 564 * in the range. 565 */ 566 res.start = mstart; 567 res.end = mend - 1; 568 ret = func(&res, kbuf); 569 if (ret) 570 break; 571 } 572 } else { 573 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, 574 &mstart, &mend, NULL) { 575 /* 576 * In memblock, end points to the first byte after the 577 * range while in kexec, end points to the last byte 578 * in the range. 579 */ 580 res.start = mstart; 581 res.end = mend - 1; 582 ret = func(&res, kbuf); 583 if (ret) 584 break; 585 } 586 } 587 588 return ret; 589} 590#else 591static int kexec_walk_memblock(struct kexec_buf *kbuf, 592 int (*func)(struct resource *, void *)) 593{ 594 return 0; 595} 596#endif 597 598/** 599 * kexec_walk_resources - call func(data) on free memory regions 600 * @kbuf: Context info for the search. Also passed to @func. 601 * @func: Function to call for each memory region. 602 * 603 * Return: The memory walk will stop when func returns a non-zero value 604 * and that value will be returned. If all free regions are visited without 605 * func returning non-zero, then zero will be returned. 606 */ 607static int kexec_walk_resources(struct kexec_buf *kbuf, 608 int (*func)(struct resource *, void *)) 609{ 610#ifdef CONFIG_CRASH_DUMP 611 if (kbuf->image->type == KEXEC_TYPE_CRASH) 612 return walk_iomem_res_desc(crashk_res.desc, 613 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, 614 crashk_res.start, crashk_res.end, 615 kbuf, func); 616#endif 617 if (kbuf->top_down) 618 return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func); 619 else 620 return walk_system_ram_res(0, ULONG_MAX, kbuf, func); 621} 622 623/** 624 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel 625 * @kbuf: Parameters for the memory search. 626 * 627 * On success, kbuf->mem will have the start address of the memory region found. 628 * 629 * Return: 0 on success, negative errno on error. 630 */ 631int kexec_locate_mem_hole(struct kexec_buf *kbuf) 632{ 633 int ret; 634 635 /* Arch knows where to place */ 636 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) 637 return 0; 638 639 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 640 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); 641 else 642 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback); 643 644 return ret == 1 ? 0 : -EADDRNOTAVAIL; 645} 646 647/** 648 * kexec_add_buffer - place a buffer in a kexec segment 649 * @kbuf: Buffer contents and memory parameters. 650 * 651 * This function assumes that kexec_lock is held. 652 * On successful return, @kbuf->mem will have the physical address of 653 * the buffer in memory. 654 * 655 * Return: 0 on success, negative errno on error. 656 */ 657int kexec_add_buffer(struct kexec_buf *kbuf) 658{ 659 struct kexec_segment *ksegment; 660 int ret; 661 662 /* Currently adding segment this way is allowed only in file mode */ 663 if (!kbuf->image->file_mode) 664 return -EINVAL; 665 666 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) 667 return -EINVAL; 668 669 /* 670 * Make sure we are not trying to add buffer after allocating 671 * control pages. All segments need to be placed first before 672 * any control pages are allocated. As control page allocation 673 * logic goes through list of segments to make sure there are 674 * no destination overlaps. 675 */ 676 if (!list_empty(&kbuf->image->control_pages)) { 677 WARN_ON(1); 678 return -EINVAL; 679 } 680 681 /* Ensure minimum alignment needed for segments. */ 682 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); 683 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); 684 685 /* Walk the RAM ranges and allocate a suitable range for the buffer */ 686 ret = arch_kexec_locate_mem_hole(kbuf); 687 if (ret) 688 return ret; 689 690 /* Found a suitable memory range */ 691 ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; 692 ksegment->kbuf = kbuf->buffer; 693 ksegment->bufsz = kbuf->bufsz; 694 ksegment->mem = kbuf->mem; 695 ksegment->memsz = kbuf->memsz; 696 kbuf->image->nr_segments++; 697 return 0; 698} 699 700/* Calculate and store the digest of segments */ 701static int kexec_calculate_store_digests(struct kimage *image) 702{ 703 struct crypto_shash *tfm; 704 struct shash_desc *desc; 705 int ret = 0, i, j, zero_buf_sz, sha_region_sz; 706 size_t desc_size, nullsz; 707 char *digest; 708 void *zero_buf; 709 struct kexec_sha_region *sha_regions; 710 struct purgatory_info *pi = &image->purgatory_info; 711 712 if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY)) 713 return 0; 714 715 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); 716 zero_buf_sz = PAGE_SIZE; 717 718 tfm = crypto_alloc_shash("sha256", 0, 0); 719 if (IS_ERR(tfm)) { 720 ret = PTR_ERR(tfm); 721 goto out; 722 } 723 724 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); 725 desc = kzalloc(desc_size, GFP_KERNEL); 726 if (!desc) { 727 ret = -ENOMEM; 728 goto out_free_tfm; 729 } 730 731 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); 732 sha_regions = vzalloc(sha_region_sz); 733 if (!sha_regions) { 734 ret = -ENOMEM; 735 goto out_free_desc; 736 } 737 738 desc->tfm = tfm; 739 740 ret = crypto_shash_init(desc); 741 if (ret < 0) 742 goto out_free_sha_regions; 743 744 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); 745 if (!digest) { 746 ret = -ENOMEM; 747 goto out_free_sha_regions; 748 } 749 750 for (j = i = 0; i < image->nr_segments; i++) { 751 struct kexec_segment *ksegment; 752 753#ifdef CONFIG_CRASH_HOTPLUG 754 /* Exclude elfcorehdr segment to allow future changes via hotplug */ 755 if (j == image->elfcorehdr_index) 756 continue; 757#endif 758 759 ksegment = &image->segment[i]; 760 /* 761 * Skip purgatory as it will be modified once we put digest 762 * info in purgatory. 763 */ 764 if (ksegment->kbuf == pi->purgatory_buf) 765 continue; 766 767 ret = crypto_shash_update(desc, ksegment->kbuf, 768 ksegment->bufsz); 769 if (ret) 770 break; 771 772 /* 773 * Assume rest of the buffer is filled with zero and 774 * update digest accordingly. 775 */ 776 nullsz = ksegment->memsz - ksegment->bufsz; 777 while (nullsz) { 778 unsigned long bytes = nullsz; 779 780 if (bytes > zero_buf_sz) 781 bytes = zero_buf_sz; 782 ret = crypto_shash_update(desc, zero_buf, bytes); 783 if (ret) 784 break; 785 nullsz -= bytes; 786 } 787 788 if (ret) 789 break; 790 791 sha_regions[j].start = ksegment->mem; 792 sha_regions[j].len = ksegment->memsz; 793 j++; 794 } 795 796 if (!ret) { 797 ret = crypto_shash_final(desc, digest); 798 if (ret) 799 goto out_free_digest; 800 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", 801 sha_regions, sha_region_sz, 0); 802 if (ret) 803 goto out_free_digest; 804 805 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", 806 digest, SHA256_DIGEST_SIZE, 0); 807 if (ret) 808 goto out_free_digest; 809 } 810 811out_free_digest: 812 kfree(digest); 813out_free_sha_regions: 814 vfree(sha_regions); 815out_free_desc: 816 kfree(desc); 817out_free_tfm: 818 kfree(tfm); 819out: 820 return ret; 821} 822 823#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY 824/* 825 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. 826 * @pi: Purgatory to be loaded. 827 * @kbuf: Buffer to setup. 828 * 829 * Allocates the memory needed for the buffer. Caller is responsible to free 830 * the memory after use. 831 * 832 * Return: 0 on success, negative errno on error. 833 */ 834static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, 835 struct kexec_buf *kbuf) 836{ 837 const Elf_Shdr *sechdrs; 838 unsigned long bss_align; 839 unsigned long bss_sz; 840 unsigned long align; 841 int i, ret; 842 843 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 844 kbuf->buf_align = bss_align = 1; 845 kbuf->bufsz = bss_sz = 0; 846 847 for (i = 0; i < pi->ehdr->e_shnum; i++) { 848 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 849 continue; 850 851 align = sechdrs[i].sh_addralign; 852 if (sechdrs[i].sh_type != SHT_NOBITS) { 853 if (kbuf->buf_align < align) 854 kbuf->buf_align = align; 855 kbuf->bufsz = ALIGN(kbuf->bufsz, align); 856 kbuf->bufsz += sechdrs[i].sh_size; 857 } else { 858 if (bss_align < align) 859 bss_align = align; 860 bss_sz = ALIGN(bss_sz, align); 861 bss_sz += sechdrs[i].sh_size; 862 } 863 } 864 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); 865 kbuf->memsz = kbuf->bufsz + bss_sz; 866 if (kbuf->buf_align < bss_align) 867 kbuf->buf_align = bss_align; 868 869 kbuf->buffer = vzalloc(kbuf->bufsz); 870 if (!kbuf->buffer) 871 return -ENOMEM; 872 pi->purgatory_buf = kbuf->buffer; 873 874 ret = kexec_add_buffer(kbuf); 875 if (ret) 876 goto out; 877 878 return 0; 879out: 880 vfree(pi->purgatory_buf); 881 pi->purgatory_buf = NULL; 882 return ret; 883} 884 885/* 886 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. 887 * @pi: Purgatory to be loaded. 888 * @kbuf: Buffer prepared to store purgatory. 889 * 890 * Allocates the memory needed for the buffer. Caller is responsible to free 891 * the memory after use. 892 * 893 * Return: 0 on success, negative errno on error. 894 */ 895static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, 896 struct kexec_buf *kbuf) 897{ 898 unsigned long bss_addr; 899 unsigned long offset; 900 size_t sechdrs_size; 901 Elf_Shdr *sechdrs; 902 int i; 903 904 /* 905 * The section headers in kexec_purgatory are read-only. In order to 906 * have them modifiable make a temporary copy. 907 */ 908 sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum); 909 sechdrs = vzalloc(sechdrs_size); 910 if (!sechdrs) 911 return -ENOMEM; 912 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size); 913 pi->sechdrs = sechdrs; 914 915 offset = 0; 916 bss_addr = kbuf->mem + kbuf->bufsz; 917 kbuf->image->start = pi->ehdr->e_entry; 918 919 for (i = 0; i < pi->ehdr->e_shnum; i++) { 920 unsigned long align; 921 void *src, *dst; 922 923 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 924 continue; 925 926 align = sechdrs[i].sh_addralign; 927 if (sechdrs[i].sh_type == SHT_NOBITS) { 928 bss_addr = ALIGN(bss_addr, align); 929 sechdrs[i].sh_addr = bss_addr; 930 bss_addr += sechdrs[i].sh_size; 931 continue; 932 } 933 934 offset = ALIGN(offset, align); 935 936 /* 937 * Check if the segment contains the entry point, if so, 938 * calculate the value of image->start based on it. 939 * If the compiler has produced more than one .text section 940 * (Eg: .text.hot), they are generally after the main .text 941 * section, and they shall not be used to calculate 942 * image->start. So do not re-calculate image->start if it 943 * is not set to the initial value, and warn the user so they 944 * have a chance to fix their purgatory's linker script. 945 */ 946 if (sechdrs[i].sh_flags & SHF_EXECINSTR && 947 pi->ehdr->e_entry >= sechdrs[i].sh_addr && 948 pi->ehdr->e_entry < (sechdrs[i].sh_addr 949 + sechdrs[i].sh_size) && 950 !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { 951 kbuf->image->start -= sechdrs[i].sh_addr; 952 kbuf->image->start += kbuf->mem + offset; 953 } 954 955 src = (void *)pi->ehdr + sechdrs[i].sh_offset; 956 dst = pi->purgatory_buf + offset; 957 memcpy(dst, src, sechdrs[i].sh_size); 958 959 sechdrs[i].sh_addr = kbuf->mem + offset; 960 sechdrs[i].sh_offset = offset; 961 offset += sechdrs[i].sh_size; 962 } 963 964 return 0; 965} 966 967static int kexec_apply_relocations(struct kimage *image) 968{ 969 int i, ret; 970 struct purgatory_info *pi = &image->purgatory_info; 971 const Elf_Shdr *sechdrs; 972 973 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 974 975 for (i = 0; i < pi->ehdr->e_shnum; i++) { 976 const Elf_Shdr *relsec; 977 const Elf_Shdr *symtab; 978 Elf_Shdr *section; 979 980 relsec = sechdrs + i; 981 982 if (relsec->sh_type != SHT_RELA && 983 relsec->sh_type != SHT_REL) 984 continue; 985 986 /* 987 * For section of type SHT_RELA/SHT_REL, 988 * ->sh_link contains section header index of associated 989 * symbol table. And ->sh_info contains section header 990 * index of section to which relocations apply. 991 */ 992 if (relsec->sh_info >= pi->ehdr->e_shnum || 993 relsec->sh_link >= pi->ehdr->e_shnum) 994 return -ENOEXEC; 995 996 section = pi->sechdrs + relsec->sh_info; 997 symtab = sechdrs + relsec->sh_link; 998 999 if (!(section->sh_flags & SHF_ALLOC)) 1000 continue; 1001 1002 /* 1003 * symtab->sh_link contain section header index of associated 1004 * string table. 1005 */ 1006 if (symtab->sh_link >= pi->ehdr->e_shnum) 1007 /* Invalid section number? */ 1008 continue; 1009 1010 /* 1011 * Respective architecture needs to provide support for applying 1012 * relocations of type SHT_RELA/SHT_REL. 1013 */ 1014 if (relsec->sh_type == SHT_RELA) 1015 ret = arch_kexec_apply_relocations_add(pi, section, 1016 relsec, symtab); 1017 else if (relsec->sh_type == SHT_REL) 1018 ret = arch_kexec_apply_relocations(pi, section, 1019 relsec, symtab); 1020 if (ret) 1021 return ret; 1022 } 1023 1024 return 0; 1025} 1026 1027/* 1028 * kexec_load_purgatory - Load and relocate the purgatory object. 1029 * @image: Image to add the purgatory to. 1030 * @kbuf: Memory parameters to use. 1031 * 1032 * Allocates the memory needed for image->purgatory_info.sechdrs and 1033 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible 1034 * to free the memory after use. 1035 * 1036 * Return: 0 on success, negative errno on error. 1037 */ 1038int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) 1039{ 1040 struct purgatory_info *pi = &image->purgatory_info; 1041 int ret; 1042 1043 if (kexec_purgatory_size <= 0) 1044 return -EINVAL; 1045 1046 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; 1047 1048 ret = kexec_purgatory_setup_kbuf(pi, kbuf); 1049 if (ret) 1050 return ret; 1051 1052 ret = kexec_purgatory_setup_sechdrs(pi, kbuf); 1053 if (ret) 1054 goto out_free_kbuf; 1055 1056 ret = kexec_apply_relocations(image); 1057 if (ret) 1058 goto out; 1059 1060 return 0; 1061out: 1062 vfree(pi->sechdrs); 1063 pi->sechdrs = NULL; 1064out_free_kbuf: 1065 vfree(pi->purgatory_buf); 1066 pi->purgatory_buf = NULL; 1067 return ret; 1068} 1069 1070/* 1071 * kexec_purgatory_find_symbol - find a symbol in the purgatory 1072 * @pi: Purgatory to search in. 1073 * @name: Name of the symbol. 1074 * 1075 * Return: pointer to symbol in read-only symtab on success, NULL on error. 1076 */ 1077static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 1078 const char *name) 1079{ 1080 const Elf_Shdr *sechdrs; 1081 const Elf_Ehdr *ehdr; 1082 const Elf_Sym *syms; 1083 const char *strtab; 1084 int i, k; 1085 1086 if (!pi->ehdr) 1087 return NULL; 1088 1089 ehdr = pi->ehdr; 1090 sechdrs = (void *)ehdr + ehdr->e_shoff; 1091 1092 for (i = 0; i < ehdr->e_shnum; i++) { 1093 if (sechdrs[i].sh_type != SHT_SYMTAB) 1094 continue; 1095 1096 if (sechdrs[i].sh_link >= ehdr->e_shnum) 1097 /* Invalid strtab section number */ 1098 continue; 1099 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; 1100 syms = (void *)ehdr + sechdrs[i].sh_offset; 1101 1102 /* Go through symbols for a match */ 1103 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { 1104 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) 1105 continue; 1106 1107 if (strcmp(strtab + syms[k].st_name, name) != 0) 1108 continue; 1109 1110 if (syms[k].st_shndx == SHN_UNDEF || 1111 syms[k].st_shndx >= ehdr->e_shnum) { 1112 pr_debug("Symbol: %s has bad section index %d.\n", 1113 name, syms[k].st_shndx); 1114 return NULL; 1115 } 1116 1117 /* Found the symbol we are looking for */ 1118 return &syms[k]; 1119 } 1120 } 1121 1122 return NULL; 1123} 1124 1125void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) 1126{ 1127 struct purgatory_info *pi = &image->purgatory_info; 1128 const Elf_Sym *sym; 1129 Elf_Shdr *sechdr; 1130 1131 sym = kexec_purgatory_find_symbol(pi, name); 1132 if (!sym) 1133 return ERR_PTR(-EINVAL); 1134 1135 sechdr = &pi->sechdrs[sym->st_shndx]; 1136 1137 /* 1138 * Returns the address where symbol will finally be loaded after 1139 * kexec_load_segment() 1140 */ 1141 return (void *)(sechdr->sh_addr + sym->st_value); 1142} 1143 1144/* 1145 * Get or set value of a symbol. If "get_value" is true, symbol value is 1146 * returned in buf otherwise symbol value is set based on value in buf. 1147 */ 1148int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 1149 void *buf, unsigned int size, bool get_value) 1150{ 1151 struct purgatory_info *pi = &image->purgatory_info; 1152 const Elf_Sym *sym; 1153 Elf_Shdr *sec; 1154 char *sym_buf; 1155 1156 sym = kexec_purgatory_find_symbol(pi, name); 1157 if (!sym) 1158 return -EINVAL; 1159 1160 if (sym->st_size != size) { 1161 pr_err("symbol %s size mismatch: expected %lu actual %u\n", 1162 name, (unsigned long)sym->st_size, size); 1163 return -EINVAL; 1164 } 1165 1166 sec = pi->sechdrs + sym->st_shndx; 1167 1168 if (sec->sh_type == SHT_NOBITS) { 1169 pr_err("symbol %s is in a bss section. Cannot %s\n", name, 1170 get_value ? "get" : "set"); 1171 return -EINVAL; 1172 } 1173 1174 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; 1175 1176 if (get_value) 1177 memcpy((void *)buf, sym_buf, size); 1178 else 1179 memcpy((void *)sym_buf, buf, size); 1180 1181 return 0; 1182} 1183#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */ 1184