1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * kexec: kexec_file_load system call 4 * 5 * Copyright (C) 2014 Red Hat Inc. 6 * Authors: 7 * Vivek Goyal <vgoyal@redhat.com> 8 */ 9 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 12 #include <linux/capability.h> 13 #include <linux/mm.h> 14 #include <linux/file.h> 15 #include <linux/slab.h> 16 #include <linux/kexec.h> 17 #include <linux/memblock.h> 18 #include <linux/mutex.h> 19 #include <linux/list.h> 20 #include <linux/fs.h> 21 #include <linux/ima.h> 22 #include <crypto/hash.h> 23 #include <crypto/sha.h> 24 #include <linux/elf.h> 25 #include <linux/elfcore.h> 26 #include <linux/kernel.h> 27 #include <linux/syscalls.h> 28 #include <linux/vmalloc.h> 29 #include "kexec_internal.h" 30 31 static int kexec_calculate_store_digests(struct kimage *image); 32 33 /* 34 * Currently this is the only default function that is exported as some 35 * architectures need it to do additional handlings. 36 * In the future, other default functions may be exported too if required. 37 */ 38 int kexec_image_probe_default(struct kimage *image, void *buf, 39 unsigned long buf_len) 40 { 41 const struct kexec_file_ops * const *fops; 42 int ret = -ENOEXEC; 43 44 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) { 45 ret = (*fops)->probe(buf, buf_len); 46 if (!ret) { 47 image->fops = *fops; 48 return ret; 49 } 50 } 51 52 return ret; 53 } 54 55 /* Architectures can provide this probe function */ 56 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, 57 unsigned long buf_len) 58 { 59 return kexec_image_probe_default(image, buf, buf_len); 60 } 61 62 static void *kexec_image_load_default(struct kimage *image) 63 { 64 if (!image->fops || !image->fops->load) 65 return ERR_PTR(-ENOEXEC); 66 67 return image->fops->load(image, image->kernel_buf, 68 image->kernel_buf_len, image->initrd_buf, 69 image->initrd_buf_len, image->cmdline_buf, 70 image->cmdline_buf_len); 71 } 72 73 void * __weak arch_kexec_kernel_image_load(struct kimage *image) 74 { 75 return kexec_image_load_default(image); 76 } 77 78 int kexec_image_post_load_cleanup_default(struct kimage *image) 79 { 80 if (!image->fops || !image->fops->cleanup) 81 return 0; 82 83 return image->fops->cleanup(image->image_loader_data); 84 } 85 86 int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) 87 { 88 return kexec_image_post_load_cleanup_default(image); 89 } 90 91 #ifdef CONFIG_KEXEC_SIG 92 static int kexec_image_verify_sig_default(struct kimage *image, void *buf, 93 unsigned long buf_len) 94 { 95 if (!image->fops || !image->fops->verify_sig) { 96 pr_debug("kernel loader does not support signature verification.\n"); 97 return -EKEYREJECTED; 98 } 99 100 return image->fops->verify_sig(buf, buf_len); 101 } 102 103 int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, 104 unsigned long buf_len) 105 { 106 return kexec_image_verify_sig_default(image, buf, buf_len); 107 } 108 #endif 109 110 /* 111 * arch_kexec_apply_relocations_add - apply relocations of type RELA 112 * @pi: Purgatory to be relocated. 113 * @section: Section relocations applying to. 114 * @relsec: Section containing RELAs. 115 * @symtab: Corresponding symtab. 116 * 117 * Return: 0 on success, negative errno on error. 118 */ 119 int __weak 120 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section, 121 const Elf_Shdr *relsec, const Elf_Shdr *symtab) 122 { 123 pr_err("RELA relocation unsupported.\n"); 124 return -ENOEXEC; 125 } 126 127 /* 128 * arch_kexec_apply_relocations - apply relocations of type REL 129 * @pi: Purgatory to be relocated. 130 * @section: Section relocations applying to. 131 * @relsec: Section containing RELs. 132 * @symtab: Corresponding symtab. 133 * 134 * Return: 0 on success, negative errno on error. 135 */ 136 int __weak 137 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section, 138 const Elf_Shdr *relsec, const Elf_Shdr *symtab) 139 { 140 pr_err("REL relocation unsupported.\n"); 141 return -ENOEXEC; 142 } 143 144 /* 145 * Free up memory used by kernel, initrd, and command line. This is temporary 146 * memory allocation which is not needed any more after these buffers have 147 * been loaded into separate segments and have been copied elsewhere. 148 */ 149 void kimage_file_post_load_cleanup(struct kimage *image) 150 { 151 struct purgatory_info *pi = &image->purgatory_info; 152 153 vfree(image->kernel_buf); 154 image->kernel_buf = NULL; 155 156 vfree(image->initrd_buf); 157 image->initrd_buf = NULL; 158 159 kfree(image->cmdline_buf); 160 image->cmdline_buf = NULL; 161 162 vfree(pi->purgatory_buf); 163 pi->purgatory_buf = NULL; 164 165 vfree(pi->sechdrs); 166 pi->sechdrs = NULL; 167 168 /* See if architecture has anything to cleanup post load */ 169 arch_kimage_file_post_load_cleanup(image); 170 171 /* 172 * Above call should have called into bootloader to free up 173 * any data stored in kimage->image_loader_data. It should 174 * be ok now to free it up. 175 */ 176 kfree(image->image_loader_data); 177 image->image_loader_data = NULL; 178 } 179 180 #ifdef CONFIG_KEXEC_SIG 181 static int 182 kimage_validate_signature(struct kimage *image) 183 { 184 int ret; 185 186 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, 187 image->kernel_buf_len); 188 if (ret) { 189 190 if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) { 191 pr_notice("Enforced kernel signature verification failed (%d).\n", ret); 192 return ret; 193 } 194 195 /* 196 * If IMA is guaranteed to appraise a signature on the kexec 197 * image, permit it even if the kernel is otherwise locked 198 * down. 199 */ 200 if (!ima_appraise_signature(READING_KEXEC_IMAGE) && 201 security_locked_down(LOCKDOWN_KEXEC)) 202 return -EPERM; 203 204 pr_debug("kernel signature verification failed (%d).\n", ret); 205 } 206 207 return 0; 208 } 209 #endif 210 211 /* 212 * In file mode list of segments is prepared by kernel. Copy relevant 213 * data from user space, do error checking, prepare segment list 214 */ 215 static int 216 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, 217 const char __user *cmdline_ptr, 218 unsigned long cmdline_len, unsigned flags) 219 { 220 int ret; 221 void *ldata; 222 loff_t size; 223 224 ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, 225 &size, INT_MAX, READING_KEXEC_IMAGE); 226 if (ret) 227 return ret; 228 image->kernel_buf_len = size; 229 230 /* Call arch image probe handlers */ 231 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, 232 image->kernel_buf_len); 233 if (ret) 234 goto out; 235 236 #ifdef CONFIG_KEXEC_SIG 237 ret = kimage_validate_signature(image); 238 239 if (ret) 240 goto out; 241 #endif 242 /* It is possible that there no initramfs is being loaded */ 243 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { 244 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, 245 &size, INT_MAX, 246 READING_KEXEC_INITRAMFS); 247 if (ret) 248 goto out; 249 image->initrd_buf_len = size; 250 } 251 252 if (cmdline_len) { 253 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len); 254 if (IS_ERR(image->cmdline_buf)) { 255 ret = PTR_ERR(image->cmdline_buf); 256 image->cmdline_buf = NULL; 257 goto out; 258 } 259 260 image->cmdline_buf_len = cmdline_len; 261 262 /* command line should be a string with last byte null */ 263 if (image->cmdline_buf[cmdline_len - 1] != '\0') { 264 ret = -EINVAL; 265 goto out; 266 } 267 268 ima_kexec_cmdline(kernel_fd, image->cmdline_buf, 269 image->cmdline_buf_len - 1); 270 } 271 272 /* IMA needs to pass the measurement list to the next kernel. */ 273 ima_add_kexec_buffer(image); 274 275 /* Call arch image load handlers */ 276 ldata = arch_kexec_kernel_image_load(image); 277 278 if (IS_ERR(ldata)) { 279 ret = PTR_ERR(ldata); 280 goto out; 281 } 282 283 image->image_loader_data = ldata; 284 out: 285 /* In case of error, free up all allocated memory in this function */ 286 if (ret) 287 kimage_file_post_load_cleanup(image); 288 return ret; 289 } 290 291 static int 292 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, 293 int initrd_fd, const char __user *cmdline_ptr, 294 unsigned long cmdline_len, unsigned long flags) 295 { 296 int ret; 297 struct kimage *image; 298 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; 299 300 image = do_kimage_alloc_init(); 301 if (!image) 302 return -ENOMEM; 303 304 image->file_mode = 1; 305 306 if (kexec_on_panic) { 307 /* Enable special crash kernel control page alloc policy. */ 308 image->control_page = crashk_res.start; 309 image->type = KEXEC_TYPE_CRASH; 310 } 311 312 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, 313 cmdline_ptr, cmdline_len, flags); 314 if (ret) 315 goto out_free_image; 316 317 ret = sanity_check_segment_list(image); 318 if (ret) 319 goto out_free_post_load_bufs; 320 321 ret = -ENOMEM; 322 image->control_code_page = kimage_alloc_control_pages(image, 323 get_order(KEXEC_CONTROL_PAGE_SIZE)); 324 if (!image->control_code_page) { 325 pr_err("Could not allocate control_code_buffer\n"); 326 goto out_free_post_load_bufs; 327 } 328 329 if (!kexec_on_panic) { 330 image->swap_page = kimage_alloc_control_pages(image, 0); 331 if (!image->swap_page) { 332 pr_err("Could not allocate swap buffer\n"); 333 goto out_free_control_pages; 334 } 335 } 336 337 *rimage = image; 338 return 0; 339 out_free_control_pages: 340 kimage_free_page_list(&image->control_pages); 341 out_free_post_load_bufs: 342 kimage_file_post_load_cleanup(image); 343 out_free_image: 344 kfree(image); 345 return ret; 346 } 347 348 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, 349 unsigned long, cmdline_len, const char __user *, cmdline_ptr, 350 unsigned long, flags) 351 { 352 int ret = 0, i; 353 struct kimage **dest_image, *image; 354 355 /* We only trust the superuser with rebooting the system. */ 356 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) 357 return -EPERM; 358 359 /* Make sure we have a legal set of flags */ 360 if (flags != (flags & KEXEC_FILE_FLAGS)) 361 return -EINVAL; 362 363 image = NULL; 364 365 if (!mutex_trylock(&kexec_mutex)) 366 return -EBUSY; 367 368 dest_image = &kexec_image; 369 if (flags & KEXEC_FILE_ON_CRASH) { 370 dest_image = &kexec_crash_image; 371 if (kexec_crash_image) 372 arch_kexec_unprotect_crashkres(); 373 } 374 375 if (flags & KEXEC_FILE_UNLOAD) 376 goto exchange; 377 378 /* 379 * In case of crash, new kernel gets loaded in reserved region. It is 380 * same memory where old crash kernel might be loaded. Free any 381 * current crash dump kernel before we corrupt it. 382 */ 383 if (flags & KEXEC_FILE_ON_CRASH) 384 kimage_free(xchg(&kexec_crash_image, NULL)); 385 386 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, 387 cmdline_len, flags); 388 if (ret) 389 goto out; 390 391 ret = machine_kexec_prepare(image); 392 if (ret) 393 goto out; 394 395 /* 396 * Some architecture(like S390) may touch the crash memory before 397 * machine_kexec_prepare(), we must copy vmcoreinfo data after it. 398 */ 399 ret = kimage_crash_copy_vmcoreinfo(image); 400 if (ret) 401 goto out; 402 403 ret = kexec_calculate_store_digests(image); 404 if (ret) 405 goto out; 406 407 for (i = 0; i < image->nr_segments; i++) { 408 struct kexec_segment *ksegment; 409 410 ksegment = &image->segment[i]; 411 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", 412 i, ksegment->buf, ksegment->bufsz, ksegment->mem, 413 ksegment->memsz); 414 415 ret = kimage_load_segment(image, &image->segment[i]); 416 if (ret) 417 goto out; 418 } 419 420 kimage_terminate(image); 421 422 ret = machine_kexec_post_load(image); 423 if (ret) 424 goto out; 425 426 /* 427 * Free up any temporary buffers allocated which are not needed 428 * after image has been loaded 429 */ 430 kimage_file_post_load_cleanup(image); 431 exchange: 432 image = xchg(dest_image, image); 433 out: 434 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) 435 arch_kexec_protect_crashkres(); 436 437 mutex_unlock(&kexec_mutex); 438 kimage_free(image); 439 return ret; 440 } 441 442 static int locate_mem_hole_top_down(unsigned long start, unsigned long end, 443 struct kexec_buf *kbuf) 444 { 445 struct kimage *image = kbuf->image; 446 unsigned long temp_start, temp_end; 447 448 temp_end = min(end, kbuf->buf_max); 449 temp_start = temp_end - kbuf->memsz; 450 451 do { 452 /* align down start */ 453 temp_start = temp_start & (~(kbuf->buf_align - 1)); 454 455 if (temp_start < start || temp_start < kbuf->buf_min) 456 return 0; 457 458 temp_end = temp_start + kbuf->memsz - 1; 459 460 /* 461 * Make sure this does not conflict with any of existing 462 * segments 463 */ 464 if (kimage_is_destination_range(image, temp_start, temp_end)) { 465 temp_start = temp_start - PAGE_SIZE; 466 continue; 467 } 468 469 /* We found a suitable memory range */ 470 break; 471 } while (1); 472 473 /* If we are here, we found a suitable memory range */ 474 kbuf->mem = temp_start; 475 476 /* Success, stop navigating through remaining System RAM ranges */ 477 return 1; 478 } 479 480 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, 481 struct kexec_buf *kbuf) 482 { 483 struct kimage *image = kbuf->image; 484 unsigned long temp_start, temp_end; 485 486 temp_start = max(start, kbuf->buf_min); 487 488 do { 489 temp_start = ALIGN(temp_start, kbuf->buf_align); 490 temp_end = temp_start + kbuf->memsz - 1; 491 492 if (temp_end > end || temp_end > kbuf->buf_max) 493 return 0; 494 /* 495 * Make sure this does not conflict with any of existing 496 * segments 497 */ 498 if (kimage_is_destination_range(image, temp_start, temp_end)) { 499 temp_start = temp_start + PAGE_SIZE; 500 continue; 501 } 502 503 /* We found a suitable memory range */ 504 break; 505 } while (1); 506 507 /* If we are here, we found a suitable memory range */ 508 kbuf->mem = temp_start; 509 510 /* Success, stop navigating through remaining System RAM ranges */ 511 return 1; 512 } 513 514 static int locate_mem_hole_callback(struct resource *res, void *arg) 515 { 516 struct kexec_buf *kbuf = (struct kexec_buf *)arg; 517 u64 start = res->start, end = res->end; 518 unsigned long sz = end - start + 1; 519 520 /* Returning 0 will take to next memory range */ 521 522 /* Don't use memory that will be detected and handled by a driver. */ 523 if (res->flags & IORESOURCE_MEM_DRIVER_MANAGED) 524 return 0; 525 526 if (sz < kbuf->memsz) 527 return 0; 528 529 if (end < kbuf->buf_min || start > kbuf->buf_max) 530 return 0; 531 532 /* 533 * Allocate memory top down with-in ram range. Otherwise bottom up 534 * allocation. 535 */ 536 if (kbuf->top_down) 537 return locate_mem_hole_top_down(start, end, kbuf); 538 return locate_mem_hole_bottom_up(start, end, kbuf); 539 } 540 541 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK 542 static int kexec_walk_memblock(struct kexec_buf *kbuf, 543 int (*func)(struct resource *, void *)) 544 { 545 int ret = 0; 546 u64 i; 547 phys_addr_t mstart, mend; 548 struct resource res = { }; 549 550 if (kbuf->image->type == KEXEC_TYPE_CRASH) 551 return func(&crashk_res, kbuf); 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 586 static 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 */ 602 static int kexec_walk_resources(struct kexec_buf *kbuf, 603 int (*func)(struct resource *, void *)) 604 { 605 if (kbuf->image->type == KEXEC_TYPE_CRASH) 606 return walk_iomem_res_desc(crashk_res.desc, 607 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, 608 crashk_res.start, crashk_res.end, 609 kbuf, func); 610 else 611 return walk_system_ram_res(0, ULONG_MAX, kbuf, func); 612 } 613 614 /** 615 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel 616 * @kbuf: Parameters for the memory search. 617 * 618 * On success, kbuf->mem will have the start address of the memory region found. 619 * 620 * Return: 0 on success, negative errno on error. 621 */ 622 int kexec_locate_mem_hole(struct kexec_buf *kbuf) 623 { 624 int ret; 625 626 /* Arch knows where to place */ 627 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) 628 return 0; 629 630 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 631 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); 632 else 633 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback); 634 635 return ret == 1 ? 0 : -EADDRNOTAVAIL; 636 } 637 638 /** 639 * arch_kexec_locate_mem_hole - Find free memory to place the segments. 640 * @kbuf: Parameters for the memory search. 641 * 642 * On success, kbuf->mem will have the start address of the memory region found. 643 * 644 * Return: 0 on success, negative errno on error. 645 */ 646 int __weak arch_kexec_locate_mem_hole(struct kexec_buf *kbuf) 647 { 648 return kexec_locate_mem_hole(kbuf); 649 } 650 651 /** 652 * kexec_add_buffer - place a buffer in a kexec segment 653 * @kbuf: Buffer contents and memory parameters. 654 * 655 * This function assumes that kexec_mutex is held. 656 * On successful return, @kbuf->mem will have the physical address of 657 * the buffer in memory. 658 * 659 * Return: 0 on success, negative errno on error. 660 */ 661 int kexec_add_buffer(struct kexec_buf *kbuf) 662 { 663 struct kexec_segment *ksegment; 664 int ret; 665 666 /* Currently adding segment this way is allowed only in file mode */ 667 if (!kbuf->image->file_mode) 668 return -EINVAL; 669 670 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) 671 return -EINVAL; 672 673 /* 674 * Make sure we are not trying to add buffer after allocating 675 * control pages. All segments need to be placed first before 676 * any control pages are allocated. As control page allocation 677 * logic goes through list of segments to make sure there are 678 * no destination overlaps. 679 */ 680 if (!list_empty(&kbuf->image->control_pages)) { 681 WARN_ON(1); 682 return -EINVAL; 683 } 684 685 /* Ensure minimum alignment needed for segments. */ 686 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); 687 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); 688 689 /* Walk the RAM ranges and allocate a suitable range for the buffer */ 690 ret = arch_kexec_locate_mem_hole(kbuf); 691 if (ret) 692 return ret; 693 694 /* Found a suitable memory range */ 695 ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; 696 ksegment->kbuf = kbuf->buffer; 697 ksegment->bufsz = kbuf->bufsz; 698 ksegment->mem = kbuf->mem; 699 ksegment->memsz = kbuf->memsz; 700 kbuf->image->nr_segments++; 701 return 0; 702 } 703 704 /* Calculate and store the digest of segments */ 705 static int kexec_calculate_store_digests(struct kimage *image) 706 { 707 struct crypto_shash *tfm; 708 struct shash_desc *desc; 709 int ret = 0, i, j, zero_buf_sz, sha_region_sz; 710 size_t desc_size, nullsz; 711 char *digest; 712 void *zero_buf; 713 struct kexec_sha_region *sha_regions; 714 struct purgatory_info *pi = &image->purgatory_info; 715 716 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY)) 717 return 0; 718 719 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); 720 zero_buf_sz = PAGE_SIZE; 721 722 tfm = crypto_alloc_shash("sha256", 0, 0); 723 if (IS_ERR(tfm)) { 724 ret = PTR_ERR(tfm); 725 goto out; 726 } 727 728 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); 729 desc = kzalloc(desc_size, GFP_KERNEL); 730 if (!desc) { 731 ret = -ENOMEM; 732 goto out_free_tfm; 733 } 734 735 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); 736 sha_regions = vzalloc(sha_region_sz); 737 if (!sha_regions) 738 goto out_free_desc; 739 740 desc->tfm = tfm; 741 742 ret = crypto_shash_init(desc); 743 if (ret < 0) 744 goto out_free_sha_regions; 745 746 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); 747 if (!digest) { 748 ret = -ENOMEM; 749 goto out_free_sha_regions; 750 } 751 752 for (j = i = 0; i < image->nr_segments; i++) { 753 struct kexec_segment *ksegment; 754 755 ksegment = &image->segment[i]; 756 /* 757 * Skip purgatory as it will be modified once we put digest 758 * info in purgatory. 759 */ 760 if (ksegment->kbuf == pi->purgatory_buf) 761 continue; 762 763 ret = crypto_shash_update(desc, ksegment->kbuf, 764 ksegment->bufsz); 765 if (ret) 766 break; 767 768 /* 769 * Assume rest of the buffer is filled with zero and 770 * update digest accordingly. 771 */ 772 nullsz = ksegment->memsz - ksegment->bufsz; 773 while (nullsz) { 774 unsigned long bytes = nullsz; 775 776 if (bytes > zero_buf_sz) 777 bytes = zero_buf_sz; 778 ret = crypto_shash_update(desc, zero_buf, bytes); 779 if (ret) 780 break; 781 nullsz -= bytes; 782 } 783 784 if (ret) 785 break; 786 787 sha_regions[j].start = ksegment->mem; 788 sha_regions[j].len = ksegment->memsz; 789 j++; 790 } 791 792 if (!ret) { 793 ret = crypto_shash_final(desc, digest); 794 if (ret) 795 goto out_free_digest; 796 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", 797 sha_regions, sha_region_sz, 0); 798 if (ret) 799 goto out_free_digest; 800 801 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", 802 digest, SHA256_DIGEST_SIZE, 0); 803 if (ret) 804 goto out_free_digest; 805 } 806 807 out_free_digest: 808 kfree(digest); 809 out_free_sha_regions: 810 vfree(sha_regions); 811 out_free_desc: 812 kfree(desc); 813 out_free_tfm: 814 kfree(tfm); 815 out: 816 return ret; 817 } 818 819 #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY 820 /* 821 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. 822 * @pi: Purgatory to be loaded. 823 * @kbuf: Buffer to setup. 824 * 825 * Allocates the memory needed for the buffer. Caller is responsible to free 826 * the memory after use. 827 * 828 * Return: 0 on success, negative errno on error. 829 */ 830 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, 831 struct kexec_buf *kbuf) 832 { 833 const Elf_Shdr *sechdrs; 834 unsigned long bss_align; 835 unsigned long bss_sz; 836 unsigned long align; 837 int i, ret; 838 839 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 840 kbuf->buf_align = bss_align = 1; 841 kbuf->bufsz = bss_sz = 0; 842 843 for (i = 0; i < pi->ehdr->e_shnum; i++) { 844 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 845 continue; 846 847 align = sechdrs[i].sh_addralign; 848 if (sechdrs[i].sh_type != SHT_NOBITS) { 849 if (kbuf->buf_align < align) 850 kbuf->buf_align = align; 851 kbuf->bufsz = ALIGN(kbuf->bufsz, align); 852 kbuf->bufsz += sechdrs[i].sh_size; 853 } else { 854 if (bss_align < align) 855 bss_align = align; 856 bss_sz = ALIGN(bss_sz, align); 857 bss_sz += sechdrs[i].sh_size; 858 } 859 } 860 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); 861 kbuf->memsz = kbuf->bufsz + bss_sz; 862 if (kbuf->buf_align < bss_align) 863 kbuf->buf_align = bss_align; 864 865 kbuf->buffer = vzalloc(kbuf->bufsz); 866 if (!kbuf->buffer) 867 return -ENOMEM; 868 pi->purgatory_buf = kbuf->buffer; 869 870 ret = kexec_add_buffer(kbuf); 871 if (ret) 872 goto out; 873 874 return 0; 875 out: 876 vfree(pi->purgatory_buf); 877 pi->purgatory_buf = NULL; 878 return ret; 879 } 880 881 /* 882 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. 883 * @pi: Purgatory to be loaded. 884 * @kbuf: Buffer prepared to store purgatory. 885 * 886 * Allocates the memory needed for the buffer. Caller is responsible to free 887 * the memory after use. 888 * 889 * Return: 0 on success, negative errno on error. 890 */ 891 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, 892 struct kexec_buf *kbuf) 893 { 894 unsigned long bss_addr; 895 unsigned long offset; 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 = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum)); 904 if (!sechdrs) 905 return -ENOMEM; 906 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, 907 pi->ehdr->e_shnum * sizeof(Elf_Shdr)); 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 if (sechdrs[i].sh_flags & SHF_EXECINSTR && 931 pi->ehdr->e_entry >= sechdrs[i].sh_addr && 932 pi->ehdr->e_entry < (sechdrs[i].sh_addr 933 + sechdrs[i].sh_size)) { 934 kbuf->image->start -= sechdrs[i].sh_addr; 935 kbuf->image->start += kbuf->mem + offset; 936 } 937 938 src = (void *)pi->ehdr + sechdrs[i].sh_offset; 939 dst = pi->purgatory_buf + offset; 940 memcpy(dst, src, sechdrs[i].sh_size); 941 942 sechdrs[i].sh_addr = kbuf->mem + offset; 943 sechdrs[i].sh_offset = offset; 944 offset += sechdrs[i].sh_size; 945 } 946 947 return 0; 948 } 949 950 static int kexec_apply_relocations(struct kimage *image) 951 { 952 int i, ret; 953 struct purgatory_info *pi = &image->purgatory_info; 954 const Elf_Shdr *sechdrs; 955 956 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 957 958 for (i = 0; i < pi->ehdr->e_shnum; i++) { 959 const Elf_Shdr *relsec; 960 const Elf_Shdr *symtab; 961 Elf_Shdr *section; 962 963 relsec = sechdrs + i; 964 965 if (relsec->sh_type != SHT_RELA && 966 relsec->sh_type != SHT_REL) 967 continue; 968 969 /* 970 * For section of type SHT_RELA/SHT_REL, 971 * ->sh_link contains section header index of associated 972 * symbol table. And ->sh_info contains section header 973 * index of section to which relocations apply. 974 */ 975 if (relsec->sh_info >= pi->ehdr->e_shnum || 976 relsec->sh_link >= pi->ehdr->e_shnum) 977 return -ENOEXEC; 978 979 section = pi->sechdrs + relsec->sh_info; 980 symtab = sechdrs + relsec->sh_link; 981 982 if (!(section->sh_flags & SHF_ALLOC)) 983 continue; 984 985 /* 986 * symtab->sh_link contain section header index of associated 987 * string table. 988 */ 989 if (symtab->sh_link >= pi->ehdr->e_shnum) 990 /* Invalid section number? */ 991 continue; 992 993 /* 994 * Respective architecture needs to provide support for applying 995 * relocations of type SHT_RELA/SHT_REL. 996 */ 997 if (relsec->sh_type == SHT_RELA) 998 ret = arch_kexec_apply_relocations_add(pi, section, 999 relsec, symtab); 1000 else if (relsec->sh_type == SHT_REL) 1001 ret = arch_kexec_apply_relocations(pi, section, 1002 relsec, symtab); 1003 if (ret) 1004 return ret; 1005 } 1006 1007 return 0; 1008 } 1009 1010 /* 1011 * kexec_load_purgatory - Load and relocate the purgatory object. 1012 * @image: Image to add the purgatory to. 1013 * @kbuf: Memory parameters to use. 1014 * 1015 * Allocates the memory needed for image->purgatory_info.sechdrs and 1016 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible 1017 * to free the memory after use. 1018 * 1019 * Return: 0 on success, negative errno on error. 1020 */ 1021 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) 1022 { 1023 struct purgatory_info *pi = &image->purgatory_info; 1024 int ret; 1025 1026 if (kexec_purgatory_size <= 0) 1027 return -EINVAL; 1028 1029 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; 1030 1031 ret = kexec_purgatory_setup_kbuf(pi, kbuf); 1032 if (ret) 1033 return ret; 1034 1035 ret = kexec_purgatory_setup_sechdrs(pi, kbuf); 1036 if (ret) 1037 goto out_free_kbuf; 1038 1039 ret = kexec_apply_relocations(image); 1040 if (ret) 1041 goto out; 1042 1043 return 0; 1044 out: 1045 vfree(pi->sechdrs); 1046 pi->sechdrs = NULL; 1047 out_free_kbuf: 1048 vfree(pi->purgatory_buf); 1049 pi->purgatory_buf = NULL; 1050 return ret; 1051 } 1052 1053 /* 1054 * kexec_purgatory_find_symbol - find a symbol in the purgatory 1055 * @pi: Purgatory to search in. 1056 * @name: Name of the symbol. 1057 * 1058 * Return: pointer to symbol in read-only symtab on success, NULL on error. 1059 */ 1060 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 1061 const char *name) 1062 { 1063 const Elf_Shdr *sechdrs; 1064 const Elf_Ehdr *ehdr; 1065 const Elf_Sym *syms; 1066 const char *strtab; 1067 int i, k; 1068 1069 if (!pi->ehdr) 1070 return NULL; 1071 1072 ehdr = pi->ehdr; 1073 sechdrs = (void *)ehdr + ehdr->e_shoff; 1074 1075 for (i = 0; i < ehdr->e_shnum; i++) { 1076 if (sechdrs[i].sh_type != SHT_SYMTAB) 1077 continue; 1078 1079 if (sechdrs[i].sh_link >= ehdr->e_shnum) 1080 /* Invalid strtab section number */ 1081 continue; 1082 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; 1083 syms = (void *)ehdr + sechdrs[i].sh_offset; 1084 1085 /* Go through symbols for a match */ 1086 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { 1087 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) 1088 continue; 1089 1090 if (strcmp(strtab + syms[k].st_name, name) != 0) 1091 continue; 1092 1093 if (syms[k].st_shndx == SHN_UNDEF || 1094 syms[k].st_shndx >= ehdr->e_shnum) { 1095 pr_debug("Symbol: %s has bad section index %d.\n", 1096 name, syms[k].st_shndx); 1097 return NULL; 1098 } 1099 1100 /* Found the symbol we are looking for */ 1101 return &syms[k]; 1102 } 1103 } 1104 1105 return NULL; 1106 } 1107 1108 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) 1109 { 1110 struct purgatory_info *pi = &image->purgatory_info; 1111 const Elf_Sym *sym; 1112 Elf_Shdr *sechdr; 1113 1114 sym = kexec_purgatory_find_symbol(pi, name); 1115 if (!sym) 1116 return ERR_PTR(-EINVAL); 1117 1118 sechdr = &pi->sechdrs[sym->st_shndx]; 1119 1120 /* 1121 * Returns the address where symbol will finally be loaded after 1122 * kexec_load_segment() 1123 */ 1124 return (void *)(sechdr->sh_addr + sym->st_value); 1125 } 1126 1127 /* 1128 * Get or set value of a symbol. If "get_value" is true, symbol value is 1129 * returned in buf otherwise symbol value is set based on value in buf. 1130 */ 1131 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 1132 void *buf, unsigned int size, bool get_value) 1133 { 1134 struct purgatory_info *pi = &image->purgatory_info; 1135 const Elf_Sym *sym; 1136 Elf_Shdr *sec; 1137 char *sym_buf; 1138 1139 sym = kexec_purgatory_find_symbol(pi, name); 1140 if (!sym) 1141 return -EINVAL; 1142 1143 if (sym->st_size != size) { 1144 pr_err("symbol %s size mismatch: expected %lu actual %u\n", 1145 name, (unsigned long)sym->st_size, size); 1146 return -EINVAL; 1147 } 1148 1149 sec = pi->sechdrs + sym->st_shndx; 1150 1151 if (sec->sh_type == SHT_NOBITS) { 1152 pr_err("symbol %s is in a bss section. Cannot %s\n", name, 1153 get_value ? "get" : "set"); 1154 return -EINVAL; 1155 } 1156 1157 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; 1158 1159 if (get_value) 1160 memcpy((void *)buf, sym_buf, size); 1161 else 1162 memcpy((void *)sym_buf, buf, size); 1163 1164 return 0; 1165 } 1166 #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */ 1167 1168 int crash_exclude_mem_range(struct crash_mem *mem, 1169 unsigned long long mstart, unsigned long long mend) 1170 { 1171 int i, j; 1172 unsigned long long start, end, p_start, p_end; 1173 struct crash_mem_range temp_range = {0, 0}; 1174 1175 for (i = 0; i < mem->nr_ranges; i++) { 1176 start = mem->ranges[i].start; 1177 end = mem->ranges[i].end; 1178 p_start = mstart; 1179 p_end = mend; 1180 1181 if (mstart > end || mend < start) 1182 continue; 1183 1184 /* Truncate any area outside of range */ 1185 if (mstart < start) 1186 p_start = start; 1187 if (mend > end) 1188 p_end = end; 1189 1190 /* Found completely overlapping range */ 1191 if (p_start == start && p_end == end) { 1192 mem->ranges[i].start = 0; 1193 mem->ranges[i].end = 0; 1194 if (i < mem->nr_ranges - 1) { 1195 /* Shift rest of the ranges to left */ 1196 for (j = i; j < mem->nr_ranges - 1; j++) { 1197 mem->ranges[j].start = 1198 mem->ranges[j+1].start; 1199 mem->ranges[j].end = 1200 mem->ranges[j+1].end; 1201 } 1202 1203 /* 1204 * Continue to check if there are another overlapping ranges 1205 * from the current position because of shifting the above 1206 * mem ranges. 1207 */ 1208 i--; 1209 mem->nr_ranges--; 1210 continue; 1211 } 1212 mem->nr_ranges--; 1213 return 0; 1214 } 1215 1216 if (p_start > start && p_end < end) { 1217 /* Split original range */ 1218 mem->ranges[i].end = p_start - 1; 1219 temp_range.start = p_end + 1; 1220 temp_range.end = end; 1221 } else if (p_start != start) 1222 mem->ranges[i].end = p_start - 1; 1223 else 1224 mem->ranges[i].start = p_end + 1; 1225 break; 1226 } 1227 1228 /* If a split happened, add the split to array */ 1229 if (!temp_range.end) 1230 return 0; 1231 1232 /* Split happened */ 1233 if (i == mem->max_nr_ranges - 1) 1234 return -ENOMEM; 1235 1236 /* Location where new range should go */ 1237 j = i + 1; 1238 if (j < mem->nr_ranges) { 1239 /* Move over all ranges one slot towards the end */ 1240 for (i = mem->nr_ranges - 1; i >= j; i--) 1241 mem->ranges[i + 1] = mem->ranges[i]; 1242 } 1243 1244 mem->ranges[j].start = temp_range.start; 1245 mem->ranges[j].end = temp_range.end; 1246 mem->nr_ranges++; 1247 return 0; 1248 } 1249 1250 int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, 1251 void **addr, unsigned long *sz) 1252 { 1253 Elf64_Ehdr *ehdr; 1254 Elf64_Phdr *phdr; 1255 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; 1256 unsigned char *buf; 1257 unsigned int cpu, i; 1258 unsigned long long notes_addr; 1259 unsigned long mstart, mend; 1260 1261 /* extra phdr for vmcoreinfo ELF note */ 1262 nr_phdr = nr_cpus + 1; 1263 nr_phdr += mem->nr_ranges; 1264 1265 /* 1266 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping 1267 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). 1268 * I think this is required by tools like gdb. So same physical 1269 * memory will be mapped in two ELF headers. One will contain kernel 1270 * text virtual addresses and other will have __va(physical) addresses. 1271 */ 1272 1273 nr_phdr++; 1274 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); 1275 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); 1276 1277 buf = vzalloc(elf_sz); 1278 if (!buf) 1279 return -ENOMEM; 1280 1281 ehdr = (Elf64_Ehdr *)buf; 1282 phdr = (Elf64_Phdr *)(ehdr + 1); 1283 memcpy(ehdr->e_ident, ELFMAG, SELFMAG); 1284 ehdr->e_ident[EI_CLASS] = ELFCLASS64; 1285 ehdr->e_ident[EI_DATA] = ELFDATA2LSB; 1286 ehdr->e_ident[EI_VERSION] = EV_CURRENT; 1287 ehdr->e_ident[EI_OSABI] = ELF_OSABI; 1288 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); 1289 ehdr->e_type = ET_CORE; 1290 ehdr->e_machine = ELF_ARCH; 1291 ehdr->e_version = EV_CURRENT; 1292 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1293 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1294 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1295 1296 /* Prepare one phdr of type PT_NOTE for each present CPU */ 1297 for_each_present_cpu(cpu) { 1298 phdr->p_type = PT_NOTE; 1299 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); 1300 phdr->p_offset = phdr->p_paddr = notes_addr; 1301 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); 1302 (ehdr->e_phnum)++; 1303 phdr++; 1304 } 1305 1306 /* Prepare one PT_NOTE header for vmcoreinfo */ 1307 phdr->p_type = PT_NOTE; 1308 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); 1309 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; 1310 (ehdr->e_phnum)++; 1311 phdr++; 1312 1313 /* Prepare PT_LOAD type program header for kernel text region */ 1314 if (kernel_map) { 1315 phdr->p_type = PT_LOAD; 1316 phdr->p_flags = PF_R|PF_W|PF_X; 1317 phdr->p_vaddr = (unsigned long) _text; 1318 phdr->p_filesz = phdr->p_memsz = _end - _text; 1319 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); 1320 ehdr->e_phnum++; 1321 phdr++; 1322 } 1323 1324 /* Go through all the ranges in mem->ranges[] and prepare phdr */ 1325 for (i = 0; i < mem->nr_ranges; i++) { 1326 mstart = mem->ranges[i].start; 1327 mend = mem->ranges[i].end; 1328 1329 phdr->p_type = PT_LOAD; 1330 phdr->p_flags = PF_R|PF_W|PF_X; 1331 phdr->p_offset = mstart; 1332 1333 phdr->p_paddr = mstart; 1334 phdr->p_vaddr = (unsigned long) __va(mstart); 1335 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; 1336 phdr->p_align = 0; 1337 ehdr->e_phnum++; 1338 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", 1339 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, 1340 ehdr->e_phnum, phdr->p_offset); 1341 phdr++; 1342 } 1343 1344 *addr = buf; 1345 *sz = elf_sz; 1346 return 0; 1347 } 1348