1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * kexec: kexec_file_load system call 4 * 5 * Copyright (C) 2014 Red Hat Inc. 6 * Authors: 7 * Vivek Goyal <vgoyal@redhat.com> 8 */ 9 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 12 #include <linux/capability.h> 13 #include <linux/mm.h> 14 #include <linux/file.h> 15 #include <linux/slab.h> 16 #include <linux/kexec.h> 17 #include <linux/memblock.h> 18 #include <linux/mutex.h> 19 #include <linux/list.h> 20 #include <linux/fs.h> 21 #include <linux/ima.h> 22 #include <crypto/hash.h> 23 #include <crypto/sha2.h> 24 #include <linux/elf.h> 25 #include <linux/elfcore.h> 26 #include <linux/kernel.h> 27 #include <linux/kernel_read_file.h> 28 #include <linux/syscalls.h> 29 #include <linux/vmalloc.h> 30 #include "kexec_internal.h" 31 32 #ifdef CONFIG_KEXEC_SIG 33 static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE); 34 35 void set_kexec_sig_enforced(void) 36 { 37 sig_enforce = true; 38 } 39 #endif 40 41 static int kexec_calculate_store_digests(struct kimage *image); 42 43 /* 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 */ 51 int 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 68 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 79 int 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 */ 92 void 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 } 127 128 #ifdef CONFIG_KEXEC_SIG 129 #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION 130 int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len) 131 { 132 int ret; 133 134 ret = verify_pefile_signature(kernel, kernel_len, 135 VERIFY_USE_SECONDARY_KEYRING, 136 VERIFYING_KEXEC_PE_SIGNATURE); 137 if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) { 138 ret = verify_pefile_signature(kernel, kernel_len, 139 VERIFY_USE_PLATFORM_KEYRING, 140 VERIFYING_KEXEC_PE_SIGNATURE); 141 } 142 return ret; 143 } 144 #endif 145 146 static int kexec_image_verify_sig(struct kimage *image, void *buf, 147 unsigned long buf_len) 148 { 149 if (!image->fops || !image->fops->verify_sig) { 150 pr_debug("kernel loader does not support signature verification.\n"); 151 return -EKEYREJECTED; 152 } 153 154 return image->fops->verify_sig(buf, buf_len); 155 } 156 157 static int 158 kimage_validate_signature(struct kimage *image) 159 { 160 int ret; 161 162 ret = kexec_image_verify_sig(image, image->kernel_buf, 163 image->kernel_buf_len); 164 if (ret) { 165 166 if (sig_enforce) { 167 pr_notice("Enforced kernel signature verification failed (%d).\n", ret); 168 return ret; 169 } 170 171 /* 172 * If IMA is guaranteed to appraise a signature on the kexec 173 * image, permit it even if the kernel is otherwise locked 174 * down. 175 */ 176 if (!ima_appraise_signature(READING_KEXEC_IMAGE) && 177 security_locked_down(LOCKDOWN_KEXEC)) 178 return -EPERM; 179 180 pr_debug("kernel signature verification failed (%d).\n", ret); 181 } 182 183 return 0; 184 } 185 #endif 186 187 /* 188 * In file mode list of segments is prepared by kernel. Copy relevant 189 * data from user space, do error checking, prepare segment list 190 */ 191 static int 192 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, 193 const char __user *cmdline_ptr, 194 unsigned long cmdline_len, unsigned flags) 195 { 196 ssize_t ret; 197 void *ldata; 198 199 ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf, 200 KEXEC_FILE_SIZE_MAX, NULL, 201 READING_KEXEC_IMAGE); 202 if (ret < 0) 203 return ret; 204 image->kernel_buf_len = ret; 205 206 /* Call arch image probe handlers */ 207 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, 208 image->kernel_buf_len); 209 if (ret) 210 goto out; 211 212 #ifdef CONFIG_KEXEC_SIG 213 ret = kimage_validate_signature(image); 214 215 if (ret) 216 goto out; 217 #endif 218 /* It is possible that there no initramfs is being loaded */ 219 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { 220 ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf, 221 KEXEC_FILE_SIZE_MAX, NULL, 222 READING_KEXEC_INITRAMFS); 223 if (ret < 0) 224 goto out; 225 image->initrd_buf_len = ret; 226 ret = 0; 227 } 228 229 if (cmdline_len) { 230 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len); 231 if (IS_ERR(image->cmdline_buf)) { 232 ret = PTR_ERR(image->cmdline_buf); 233 image->cmdline_buf = NULL; 234 goto out; 235 } 236 237 image->cmdline_buf_len = cmdline_len; 238 239 /* command line should be a string with last byte null */ 240 if (image->cmdline_buf[cmdline_len - 1] != '\0') { 241 ret = -EINVAL; 242 goto out; 243 } 244 245 ima_kexec_cmdline(kernel_fd, image->cmdline_buf, 246 image->cmdline_buf_len - 1); 247 } 248 249 /* IMA needs to pass the measurement list to the next kernel. */ 250 ima_add_kexec_buffer(image); 251 252 /* Call arch image load handlers */ 253 ldata = arch_kexec_kernel_image_load(image); 254 255 if (IS_ERR(ldata)) { 256 ret = PTR_ERR(ldata); 257 goto out; 258 } 259 260 image->image_loader_data = ldata; 261 out: 262 /* In case of error, free up all allocated memory in this function */ 263 if (ret) 264 kimage_file_post_load_cleanup(image); 265 return ret; 266 } 267 268 static int 269 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, 270 int initrd_fd, const char __user *cmdline_ptr, 271 unsigned long cmdline_len, unsigned long flags) 272 { 273 int ret; 274 struct kimage *image; 275 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; 276 277 image = do_kimage_alloc_init(); 278 if (!image) 279 return -ENOMEM; 280 281 image->file_mode = 1; 282 283 if (kexec_on_panic) { 284 /* Enable special crash kernel control page alloc policy. */ 285 image->control_page = crashk_res.start; 286 image->type = KEXEC_TYPE_CRASH; 287 } 288 289 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, 290 cmdline_ptr, cmdline_len, flags); 291 if (ret) 292 goto out_free_image; 293 294 ret = sanity_check_segment_list(image); 295 if (ret) 296 goto out_free_post_load_bufs; 297 298 ret = -ENOMEM; 299 image->control_code_page = kimage_alloc_control_pages(image, 300 get_order(KEXEC_CONTROL_PAGE_SIZE)); 301 if (!image->control_code_page) { 302 pr_err("Could not allocate control_code_buffer\n"); 303 goto out_free_post_load_bufs; 304 } 305 306 if (!kexec_on_panic) { 307 image->swap_page = kimage_alloc_control_pages(image, 0); 308 if (!image->swap_page) { 309 pr_err("Could not allocate swap buffer\n"); 310 goto out_free_control_pages; 311 } 312 } 313 314 *rimage = image; 315 return 0; 316 out_free_control_pages: 317 kimage_free_page_list(&image->control_pages); 318 out_free_post_load_bufs: 319 kimage_file_post_load_cleanup(image); 320 out_free_image: 321 kfree(image); 322 return ret; 323 } 324 325 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, 326 unsigned long, cmdline_len, const char __user *, cmdline_ptr, 327 unsigned long, flags) 328 { 329 int ret = 0, i; 330 struct kimage **dest_image, *image; 331 332 /* We only trust the superuser with rebooting the system. */ 333 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) 334 return -EPERM; 335 336 /* Make sure we have a legal set of flags */ 337 if (flags != (flags & KEXEC_FILE_FLAGS)) 338 return -EINVAL; 339 340 image = NULL; 341 342 if (!mutex_trylock(&kexec_mutex)) 343 return -EBUSY; 344 345 dest_image = &kexec_image; 346 if (flags & KEXEC_FILE_ON_CRASH) { 347 dest_image = &kexec_crash_image; 348 if (kexec_crash_image) 349 arch_kexec_unprotect_crashkres(); 350 } 351 352 if (flags & KEXEC_FILE_UNLOAD) 353 goto exchange; 354 355 /* 356 * In case of crash, new kernel gets loaded in reserved region. It is 357 * same memory where old crash kernel might be loaded. Free any 358 * current crash dump kernel before we corrupt it. 359 */ 360 if (flags & KEXEC_FILE_ON_CRASH) 361 kimage_free(xchg(&kexec_crash_image, NULL)); 362 363 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, 364 cmdline_len, flags); 365 if (ret) 366 goto out; 367 368 ret = machine_kexec_prepare(image); 369 if (ret) 370 goto out; 371 372 /* 373 * Some architecture(like S390) may touch the crash memory before 374 * machine_kexec_prepare(), we must copy vmcoreinfo data after it. 375 */ 376 ret = kimage_crash_copy_vmcoreinfo(image); 377 if (ret) 378 goto out; 379 380 ret = kexec_calculate_store_digests(image); 381 if (ret) 382 goto out; 383 384 for (i = 0; i < image->nr_segments; i++) { 385 struct kexec_segment *ksegment; 386 387 ksegment = &image->segment[i]; 388 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", 389 i, ksegment->buf, ksegment->bufsz, ksegment->mem, 390 ksegment->memsz); 391 392 ret = kimage_load_segment(image, &image->segment[i]); 393 if (ret) 394 goto out; 395 } 396 397 kimage_terminate(image); 398 399 ret = machine_kexec_post_load(image); 400 if (ret) 401 goto out; 402 403 /* 404 * Free up any temporary buffers allocated which are not needed 405 * after image has been loaded 406 */ 407 kimage_file_post_load_cleanup(image); 408 exchange: 409 image = xchg(dest_image, image); 410 out: 411 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) 412 arch_kexec_protect_crashkres(); 413 414 mutex_unlock(&kexec_mutex); 415 kimage_free(image); 416 return ret; 417 } 418 419 static int locate_mem_hole_top_down(unsigned long start, unsigned long end, 420 struct kexec_buf *kbuf) 421 { 422 struct kimage *image = kbuf->image; 423 unsigned long temp_start, temp_end; 424 425 temp_end = min(end, kbuf->buf_max); 426 temp_start = temp_end - kbuf->memsz; 427 428 do { 429 /* align down start */ 430 temp_start = temp_start & (~(kbuf->buf_align - 1)); 431 432 if (temp_start < start || temp_start < kbuf->buf_min) 433 return 0; 434 435 temp_end = temp_start + kbuf->memsz - 1; 436 437 /* 438 * Make sure this does not conflict with any of existing 439 * segments 440 */ 441 if (kimage_is_destination_range(image, temp_start, temp_end)) { 442 temp_start = temp_start - PAGE_SIZE; 443 continue; 444 } 445 446 /* We found a suitable memory range */ 447 break; 448 } while (1); 449 450 /* If we are here, we found a suitable memory range */ 451 kbuf->mem = temp_start; 452 453 /* Success, stop navigating through remaining System RAM ranges */ 454 return 1; 455 } 456 457 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, 458 struct kexec_buf *kbuf) 459 { 460 struct kimage *image = kbuf->image; 461 unsigned long temp_start, temp_end; 462 463 temp_start = max(start, kbuf->buf_min); 464 465 do { 466 temp_start = ALIGN(temp_start, kbuf->buf_align); 467 temp_end = temp_start + kbuf->memsz - 1; 468 469 if (temp_end > end || temp_end > kbuf->buf_max) 470 return 0; 471 /* 472 * Make sure this does not conflict with any of existing 473 * segments 474 */ 475 if (kimage_is_destination_range(image, temp_start, temp_end)) { 476 temp_start = temp_start + PAGE_SIZE; 477 continue; 478 } 479 480 /* We found a suitable memory range */ 481 break; 482 } while (1); 483 484 /* If we are here, we found a suitable memory range */ 485 kbuf->mem = temp_start; 486 487 /* Success, stop navigating through remaining System RAM ranges */ 488 return 1; 489 } 490 491 static int locate_mem_hole_callback(struct resource *res, void *arg) 492 { 493 struct kexec_buf *kbuf = (struct kexec_buf *)arg; 494 u64 start = res->start, end = res->end; 495 unsigned long sz = end - start + 1; 496 497 /* Returning 0 will take to next memory range */ 498 499 /* Don't use memory that will be detected and handled by a driver. */ 500 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) 501 return 0; 502 503 if (sz < kbuf->memsz) 504 return 0; 505 506 if (end < kbuf->buf_min || start > kbuf->buf_max) 507 return 0; 508 509 /* 510 * Allocate memory top down with-in ram range. Otherwise bottom up 511 * allocation. 512 */ 513 if (kbuf->top_down) 514 return locate_mem_hole_top_down(start, end, kbuf); 515 return locate_mem_hole_bottom_up(start, end, kbuf); 516 } 517 518 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK 519 static int kexec_walk_memblock(struct kexec_buf *kbuf, 520 int (*func)(struct resource *, void *)) 521 { 522 int ret = 0; 523 u64 i; 524 phys_addr_t mstart, mend; 525 struct resource res = { }; 526 527 if (kbuf->image->type == KEXEC_TYPE_CRASH) 528 return func(&crashk_res, kbuf); 529 530 /* 531 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See 532 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in 533 * locate_mem_hole_callback(). 534 */ 535 if (kbuf->top_down) { 536 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE, 537 &mstart, &mend, NULL) { 538 /* 539 * In memblock, end points to the first byte after the 540 * range while in kexec, end points to the last byte 541 * in the range. 542 */ 543 res.start = mstart; 544 res.end = mend - 1; 545 ret = func(&res, kbuf); 546 if (ret) 547 break; 548 } 549 } else { 550 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, 551 &mstart, &mend, NULL) { 552 /* 553 * In memblock, end points to the first byte after the 554 * range while in kexec, end points to the last byte 555 * in the range. 556 */ 557 res.start = mstart; 558 res.end = mend - 1; 559 ret = func(&res, kbuf); 560 if (ret) 561 break; 562 } 563 } 564 565 return ret; 566 } 567 #else 568 static int kexec_walk_memblock(struct kexec_buf *kbuf, 569 int (*func)(struct resource *, void *)) 570 { 571 return 0; 572 } 573 #endif 574 575 /** 576 * kexec_walk_resources - call func(data) on free memory regions 577 * @kbuf: Context info for the search. Also passed to @func. 578 * @func: Function to call for each memory region. 579 * 580 * Return: The memory walk will stop when func returns a non-zero value 581 * and that value will be returned. If all free regions are visited without 582 * func returning non-zero, then zero will be returned. 583 */ 584 static int kexec_walk_resources(struct kexec_buf *kbuf, 585 int (*func)(struct resource *, void *)) 586 { 587 if (kbuf->image->type == KEXEC_TYPE_CRASH) 588 return walk_iomem_res_desc(crashk_res.desc, 589 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, 590 crashk_res.start, crashk_res.end, 591 kbuf, func); 592 else 593 return walk_system_ram_res(0, ULONG_MAX, kbuf, func); 594 } 595 596 /** 597 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel 598 * @kbuf: Parameters for the memory search. 599 * 600 * On success, kbuf->mem will have the start address of the memory region found. 601 * 602 * Return: 0 on success, negative errno on error. 603 */ 604 int kexec_locate_mem_hole(struct kexec_buf *kbuf) 605 { 606 int ret; 607 608 /* Arch knows where to place */ 609 if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) 610 return 0; 611 612 if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 613 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); 614 else 615 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback); 616 617 return ret == 1 ? 0 : -EADDRNOTAVAIL; 618 } 619 620 /** 621 * kexec_add_buffer - place a buffer in a kexec segment 622 * @kbuf: Buffer contents and memory parameters. 623 * 624 * This function assumes that kexec_mutex is held. 625 * On successful return, @kbuf->mem will have the physical address of 626 * the buffer in memory. 627 * 628 * Return: 0 on success, negative errno on error. 629 */ 630 int kexec_add_buffer(struct kexec_buf *kbuf) 631 { 632 struct kexec_segment *ksegment; 633 int ret; 634 635 /* Currently adding segment this way is allowed only in file mode */ 636 if (!kbuf->image->file_mode) 637 return -EINVAL; 638 639 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) 640 return -EINVAL; 641 642 /* 643 * Make sure we are not trying to add buffer after allocating 644 * control pages. All segments need to be placed first before 645 * any control pages are allocated. As control page allocation 646 * logic goes through list of segments to make sure there are 647 * no destination overlaps. 648 */ 649 if (!list_empty(&kbuf->image->control_pages)) { 650 WARN_ON(1); 651 return -EINVAL; 652 } 653 654 /* Ensure minimum alignment needed for segments. */ 655 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); 656 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); 657 658 /* Walk the RAM ranges and allocate a suitable range for the buffer */ 659 ret = arch_kexec_locate_mem_hole(kbuf); 660 if (ret) 661 return ret; 662 663 /* Found a suitable memory range */ 664 ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; 665 ksegment->kbuf = kbuf->buffer; 666 ksegment->bufsz = kbuf->bufsz; 667 ksegment->mem = kbuf->mem; 668 ksegment->memsz = kbuf->memsz; 669 kbuf->image->nr_segments++; 670 return 0; 671 } 672 673 /* Calculate and store the digest of segments */ 674 static int kexec_calculate_store_digests(struct kimage *image) 675 { 676 struct crypto_shash *tfm; 677 struct shash_desc *desc; 678 int ret = 0, i, j, zero_buf_sz, sha_region_sz; 679 size_t desc_size, nullsz; 680 char *digest; 681 void *zero_buf; 682 struct kexec_sha_region *sha_regions; 683 struct purgatory_info *pi = &image->purgatory_info; 684 685 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY)) 686 return 0; 687 688 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); 689 zero_buf_sz = PAGE_SIZE; 690 691 tfm = crypto_alloc_shash("sha256", 0, 0); 692 if (IS_ERR(tfm)) { 693 ret = PTR_ERR(tfm); 694 goto out; 695 } 696 697 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); 698 desc = kzalloc(desc_size, GFP_KERNEL); 699 if (!desc) { 700 ret = -ENOMEM; 701 goto out_free_tfm; 702 } 703 704 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); 705 sha_regions = vzalloc(sha_region_sz); 706 if (!sha_regions) { 707 ret = -ENOMEM; 708 goto out_free_desc; 709 } 710 711 desc->tfm = tfm; 712 713 ret = crypto_shash_init(desc); 714 if (ret < 0) 715 goto out_free_sha_regions; 716 717 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); 718 if (!digest) { 719 ret = -ENOMEM; 720 goto out_free_sha_regions; 721 } 722 723 for (j = i = 0; i < image->nr_segments; i++) { 724 struct kexec_segment *ksegment; 725 726 ksegment = &image->segment[i]; 727 /* 728 * Skip purgatory as it will be modified once we put digest 729 * info in purgatory. 730 */ 731 if (ksegment->kbuf == pi->purgatory_buf) 732 continue; 733 734 ret = crypto_shash_update(desc, ksegment->kbuf, 735 ksegment->bufsz); 736 if (ret) 737 break; 738 739 /* 740 * Assume rest of the buffer is filled with zero and 741 * update digest accordingly. 742 */ 743 nullsz = ksegment->memsz - ksegment->bufsz; 744 while (nullsz) { 745 unsigned long bytes = nullsz; 746 747 if (bytes > zero_buf_sz) 748 bytes = zero_buf_sz; 749 ret = crypto_shash_update(desc, zero_buf, bytes); 750 if (ret) 751 break; 752 nullsz -= bytes; 753 } 754 755 if (ret) 756 break; 757 758 sha_regions[j].start = ksegment->mem; 759 sha_regions[j].len = ksegment->memsz; 760 j++; 761 } 762 763 if (!ret) { 764 ret = crypto_shash_final(desc, digest); 765 if (ret) 766 goto out_free_digest; 767 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", 768 sha_regions, sha_region_sz, 0); 769 if (ret) 770 goto out_free_digest; 771 772 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", 773 digest, SHA256_DIGEST_SIZE, 0); 774 if (ret) 775 goto out_free_digest; 776 } 777 778 out_free_digest: 779 kfree(digest); 780 out_free_sha_regions: 781 vfree(sha_regions); 782 out_free_desc: 783 kfree(desc); 784 out_free_tfm: 785 kfree(tfm); 786 out: 787 return ret; 788 } 789 790 #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY 791 /* 792 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. 793 * @pi: Purgatory to be loaded. 794 * @kbuf: Buffer to setup. 795 * 796 * Allocates the memory needed for the buffer. Caller is responsible to free 797 * the memory after use. 798 * 799 * Return: 0 on success, negative errno on error. 800 */ 801 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, 802 struct kexec_buf *kbuf) 803 { 804 const Elf_Shdr *sechdrs; 805 unsigned long bss_align; 806 unsigned long bss_sz; 807 unsigned long align; 808 int i, ret; 809 810 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 811 kbuf->buf_align = bss_align = 1; 812 kbuf->bufsz = bss_sz = 0; 813 814 for (i = 0; i < pi->ehdr->e_shnum; i++) { 815 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 816 continue; 817 818 align = sechdrs[i].sh_addralign; 819 if (sechdrs[i].sh_type != SHT_NOBITS) { 820 if (kbuf->buf_align < align) 821 kbuf->buf_align = align; 822 kbuf->bufsz = ALIGN(kbuf->bufsz, align); 823 kbuf->bufsz += sechdrs[i].sh_size; 824 } else { 825 if (bss_align < align) 826 bss_align = align; 827 bss_sz = ALIGN(bss_sz, align); 828 bss_sz += sechdrs[i].sh_size; 829 } 830 } 831 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); 832 kbuf->memsz = kbuf->bufsz + bss_sz; 833 if (kbuf->buf_align < bss_align) 834 kbuf->buf_align = bss_align; 835 836 kbuf->buffer = vzalloc(kbuf->bufsz); 837 if (!kbuf->buffer) 838 return -ENOMEM; 839 pi->purgatory_buf = kbuf->buffer; 840 841 ret = kexec_add_buffer(kbuf); 842 if (ret) 843 goto out; 844 845 return 0; 846 out: 847 vfree(pi->purgatory_buf); 848 pi->purgatory_buf = NULL; 849 return ret; 850 } 851 852 /* 853 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. 854 * @pi: Purgatory to be loaded. 855 * @kbuf: Buffer prepared to store purgatory. 856 * 857 * Allocates the memory needed for the buffer. Caller is responsible to free 858 * the memory after use. 859 * 860 * Return: 0 on success, negative errno on error. 861 */ 862 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, 863 struct kexec_buf *kbuf) 864 { 865 unsigned long bss_addr; 866 unsigned long offset; 867 Elf_Shdr *sechdrs; 868 int i; 869 870 /* 871 * The section headers in kexec_purgatory are read-only. In order to 872 * have them modifiable make a temporary copy. 873 */ 874 sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum)); 875 if (!sechdrs) 876 return -ENOMEM; 877 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, 878 pi->ehdr->e_shnum * sizeof(Elf_Shdr)); 879 pi->sechdrs = sechdrs; 880 881 offset = 0; 882 bss_addr = kbuf->mem + kbuf->bufsz; 883 kbuf->image->start = pi->ehdr->e_entry; 884 885 for (i = 0; i < pi->ehdr->e_shnum; i++) { 886 unsigned long align; 887 void *src, *dst; 888 889 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 890 continue; 891 892 align = sechdrs[i].sh_addralign; 893 if (sechdrs[i].sh_type == SHT_NOBITS) { 894 bss_addr = ALIGN(bss_addr, align); 895 sechdrs[i].sh_addr = bss_addr; 896 bss_addr += sechdrs[i].sh_size; 897 continue; 898 } 899 900 offset = ALIGN(offset, align); 901 if (sechdrs[i].sh_flags & SHF_EXECINSTR && 902 pi->ehdr->e_entry >= sechdrs[i].sh_addr && 903 pi->ehdr->e_entry < (sechdrs[i].sh_addr 904 + sechdrs[i].sh_size)) { 905 kbuf->image->start -= sechdrs[i].sh_addr; 906 kbuf->image->start += kbuf->mem + offset; 907 } 908 909 src = (void *)pi->ehdr + sechdrs[i].sh_offset; 910 dst = pi->purgatory_buf + offset; 911 memcpy(dst, src, sechdrs[i].sh_size); 912 913 sechdrs[i].sh_addr = kbuf->mem + offset; 914 sechdrs[i].sh_offset = offset; 915 offset += sechdrs[i].sh_size; 916 } 917 918 return 0; 919 } 920 921 static int kexec_apply_relocations(struct kimage *image) 922 { 923 int i, ret; 924 struct purgatory_info *pi = &image->purgatory_info; 925 const Elf_Shdr *sechdrs; 926 927 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 928 929 for (i = 0; i < pi->ehdr->e_shnum; i++) { 930 const Elf_Shdr *relsec; 931 const Elf_Shdr *symtab; 932 Elf_Shdr *section; 933 934 relsec = sechdrs + i; 935 936 if (relsec->sh_type != SHT_RELA && 937 relsec->sh_type != SHT_REL) 938 continue; 939 940 /* 941 * For section of type SHT_RELA/SHT_REL, 942 * ->sh_link contains section header index of associated 943 * symbol table. And ->sh_info contains section header 944 * index of section to which relocations apply. 945 */ 946 if (relsec->sh_info >= pi->ehdr->e_shnum || 947 relsec->sh_link >= pi->ehdr->e_shnum) 948 return -ENOEXEC; 949 950 section = pi->sechdrs + relsec->sh_info; 951 symtab = sechdrs + relsec->sh_link; 952 953 if (!(section->sh_flags & SHF_ALLOC)) 954 continue; 955 956 /* 957 * symtab->sh_link contain section header index of associated 958 * string table. 959 */ 960 if (symtab->sh_link >= pi->ehdr->e_shnum) 961 /* Invalid section number? */ 962 continue; 963 964 /* 965 * Respective architecture needs to provide support for applying 966 * relocations of type SHT_RELA/SHT_REL. 967 */ 968 if (relsec->sh_type == SHT_RELA) 969 ret = arch_kexec_apply_relocations_add(pi, section, 970 relsec, symtab); 971 else if (relsec->sh_type == SHT_REL) 972 ret = arch_kexec_apply_relocations(pi, section, 973 relsec, symtab); 974 if (ret) 975 return ret; 976 } 977 978 return 0; 979 } 980 981 /* 982 * kexec_load_purgatory - Load and relocate the purgatory object. 983 * @image: Image to add the purgatory to. 984 * @kbuf: Memory parameters to use. 985 * 986 * Allocates the memory needed for image->purgatory_info.sechdrs and 987 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible 988 * to free the memory after use. 989 * 990 * Return: 0 on success, negative errno on error. 991 */ 992 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) 993 { 994 struct purgatory_info *pi = &image->purgatory_info; 995 int ret; 996 997 if (kexec_purgatory_size <= 0) 998 return -EINVAL; 999 1000 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; 1001 1002 ret = kexec_purgatory_setup_kbuf(pi, kbuf); 1003 if (ret) 1004 return ret; 1005 1006 ret = kexec_purgatory_setup_sechdrs(pi, kbuf); 1007 if (ret) 1008 goto out_free_kbuf; 1009 1010 ret = kexec_apply_relocations(image); 1011 if (ret) 1012 goto out; 1013 1014 return 0; 1015 out: 1016 vfree(pi->sechdrs); 1017 pi->sechdrs = NULL; 1018 out_free_kbuf: 1019 vfree(pi->purgatory_buf); 1020 pi->purgatory_buf = NULL; 1021 return ret; 1022 } 1023 1024 /* 1025 * kexec_purgatory_find_symbol - find a symbol in the purgatory 1026 * @pi: Purgatory to search in. 1027 * @name: Name of the symbol. 1028 * 1029 * Return: pointer to symbol in read-only symtab on success, NULL on error. 1030 */ 1031 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 1032 const char *name) 1033 { 1034 const Elf_Shdr *sechdrs; 1035 const Elf_Ehdr *ehdr; 1036 const Elf_Sym *syms; 1037 const char *strtab; 1038 int i, k; 1039 1040 if (!pi->ehdr) 1041 return NULL; 1042 1043 ehdr = pi->ehdr; 1044 sechdrs = (void *)ehdr + ehdr->e_shoff; 1045 1046 for (i = 0; i < ehdr->e_shnum; i++) { 1047 if (sechdrs[i].sh_type != SHT_SYMTAB) 1048 continue; 1049 1050 if (sechdrs[i].sh_link >= ehdr->e_shnum) 1051 /* Invalid strtab section number */ 1052 continue; 1053 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; 1054 syms = (void *)ehdr + sechdrs[i].sh_offset; 1055 1056 /* Go through symbols for a match */ 1057 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { 1058 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) 1059 continue; 1060 1061 if (strcmp(strtab + syms[k].st_name, name) != 0) 1062 continue; 1063 1064 if (syms[k].st_shndx == SHN_UNDEF || 1065 syms[k].st_shndx >= ehdr->e_shnum) { 1066 pr_debug("Symbol: %s has bad section index %d.\n", 1067 name, syms[k].st_shndx); 1068 return NULL; 1069 } 1070 1071 /* Found the symbol we are looking for */ 1072 return &syms[k]; 1073 } 1074 } 1075 1076 return NULL; 1077 } 1078 1079 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) 1080 { 1081 struct purgatory_info *pi = &image->purgatory_info; 1082 const Elf_Sym *sym; 1083 Elf_Shdr *sechdr; 1084 1085 sym = kexec_purgatory_find_symbol(pi, name); 1086 if (!sym) 1087 return ERR_PTR(-EINVAL); 1088 1089 sechdr = &pi->sechdrs[sym->st_shndx]; 1090 1091 /* 1092 * Returns the address where symbol will finally be loaded after 1093 * kexec_load_segment() 1094 */ 1095 return (void *)(sechdr->sh_addr + sym->st_value); 1096 } 1097 1098 /* 1099 * Get or set value of a symbol. If "get_value" is true, symbol value is 1100 * returned in buf otherwise symbol value is set based on value in buf. 1101 */ 1102 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 1103 void *buf, unsigned int size, bool get_value) 1104 { 1105 struct purgatory_info *pi = &image->purgatory_info; 1106 const Elf_Sym *sym; 1107 Elf_Shdr *sec; 1108 char *sym_buf; 1109 1110 sym = kexec_purgatory_find_symbol(pi, name); 1111 if (!sym) 1112 return -EINVAL; 1113 1114 if (sym->st_size != size) { 1115 pr_err("symbol %s size mismatch: expected %lu actual %u\n", 1116 name, (unsigned long)sym->st_size, size); 1117 return -EINVAL; 1118 } 1119 1120 sec = pi->sechdrs + sym->st_shndx; 1121 1122 if (sec->sh_type == SHT_NOBITS) { 1123 pr_err("symbol %s is in a bss section. Cannot %s\n", name, 1124 get_value ? "get" : "set"); 1125 return -EINVAL; 1126 } 1127 1128 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; 1129 1130 if (get_value) 1131 memcpy((void *)buf, sym_buf, size); 1132 else 1133 memcpy((void *)sym_buf, buf, size); 1134 1135 return 0; 1136 } 1137 #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */ 1138 1139 int crash_exclude_mem_range(struct crash_mem *mem, 1140 unsigned long long mstart, unsigned long long mend) 1141 { 1142 int i, j; 1143 unsigned long long start, end, p_start, p_end; 1144 struct crash_mem_range temp_range = {0, 0}; 1145 1146 for (i = 0; i < mem->nr_ranges; i++) { 1147 start = mem->ranges[i].start; 1148 end = mem->ranges[i].end; 1149 p_start = mstart; 1150 p_end = mend; 1151 1152 if (mstart > end || mend < start) 1153 continue; 1154 1155 /* Truncate any area outside of range */ 1156 if (mstart < start) 1157 p_start = start; 1158 if (mend > end) 1159 p_end = end; 1160 1161 /* Found completely overlapping range */ 1162 if (p_start == start && p_end == end) { 1163 mem->ranges[i].start = 0; 1164 mem->ranges[i].end = 0; 1165 if (i < mem->nr_ranges - 1) { 1166 /* Shift rest of the ranges to left */ 1167 for (j = i; j < mem->nr_ranges - 1; j++) { 1168 mem->ranges[j].start = 1169 mem->ranges[j+1].start; 1170 mem->ranges[j].end = 1171 mem->ranges[j+1].end; 1172 } 1173 1174 /* 1175 * Continue to check if there are another overlapping ranges 1176 * from the current position because of shifting the above 1177 * mem ranges. 1178 */ 1179 i--; 1180 mem->nr_ranges--; 1181 continue; 1182 } 1183 mem->nr_ranges--; 1184 return 0; 1185 } 1186 1187 if (p_start > start && p_end < end) { 1188 /* Split original range */ 1189 mem->ranges[i].end = p_start - 1; 1190 temp_range.start = p_end + 1; 1191 temp_range.end = end; 1192 } else if (p_start != start) 1193 mem->ranges[i].end = p_start - 1; 1194 else 1195 mem->ranges[i].start = p_end + 1; 1196 break; 1197 } 1198 1199 /* If a split happened, add the split to array */ 1200 if (!temp_range.end) 1201 return 0; 1202 1203 /* Split happened */ 1204 if (i == mem->max_nr_ranges - 1) 1205 return -ENOMEM; 1206 1207 /* Location where new range should go */ 1208 j = i + 1; 1209 if (j < mem->nr_ranges) { 1210 /* Move over all ranges one slot towards the end */ 1211 for (i = mem->nr_ranges - 1; i >= j; i--) 1212 mem->ranges[i + 1] = mem->ranges[i]; 1213 } 1214 1215 mem->ranges[j].start = temp_range.start; 1216 mem->ranges[j].end = temp_range.end; 1217 mem->nr_ranges++; 1218 return 0; 1219 } 1220 1221 int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, 1222 void **addr, unsigned long *sz) 1223 { 1224 Elf64_Ehdr *ehdr; 1225 Elf64_Phdr *phdr; 1226 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; 1227 unsigned char *buf; 1228 unsigned int cpu, i; 1229 unsigned long long notes_addr; 1230 unsigned long mstart, mend; 1231 1232 /* extra phdr for vmcoreinfo ELF note */ 1233 nr_phdr = nr_cpus + 1; 1234 nr_phdr += mem->nr_ranges; 1235 1236 /* 1237 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping 1238 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). 1239 * I think this is required by tools like gdb. So same physical 1240 * memory will be mapped in two ELF headers. One will contain kernel 1241 * text virtual addresses and other will have __va(physical) addresses. 1242 */ 1243 1244 nr_phdr++; 1245 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); 1246 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); 1247 1248 buf = vzalloc(elf_sz); 1249 if (!buf) 1250 return -ENOMEM; 1251 1252 ehdr = (Elf64_Ehdr *)buf; 1253 phdr = (Elf64_Phdr *)(ehdr + 1); 1254 memcpy(ehdr->e_ident, ELFMAG, SELFMAG); 1255 ehdr->e_ident[EI_CLASS] = ELFCLASS64; 1256 ehdr->e_ident[EI_DATA] = ELFDATA2LSB; 1257 ehdr->e_ident[EI_VERSION] = EV_CURRENT; 1258 ehdr->e_ident[EI_OSABI] = ELF_OSABI; 1259 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); 1260 ehdr->e_type = ET_CORE; 1261 ehdr->e_machine = ELF_ARCH; 1262 ehdr->e_version = EV_CURRENT; 1263 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1264 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1265 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1266 1267 /* Prepare one phdr of type PT_NOTE for each present CPU */ 1268 for_each_present_cpu(cpu) { 1269 phdr->p_type = PT_NOTE; 1270 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); 1271 phdr->p_offset = phdr->p_paddr = notes_addr; 1272 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); 1273 (ehdr->e_phnum)++; 1274 phdr++; 1275 } 1276 1277 /* Prepare one PT_NOTE header for vmcoreinfo */ 1278 phdr->p_type = PT_NOTE; 1279 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); 1280 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; 1281 (ehdr->e_phnum)++; 1282 phdr++; 1283 1284 /* Prepare PT_LOAD type program header for kernel text region */ 1285 if (need_kernel_map) { 1286 phdr->p_type = PT_LOAD; 1287 phdr->p_flags = PF_R|PF_W|PF_X; 1288 phdr->p_vaddr = (unsigned long) _text; 1289 phdr->p_filesz = phdr->p_memsz = _end - _text; 1290 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); 1291 ehdr->e_phnum++; 1292 phdr++; 1293 } 1294 1295 /* Go through all the ranges in mem->ranges[] and prepare phdr */ 1296 for (i = 0; i < mem->nr_ranges; i++) { 1297 mstart = mem->ranges[i].start; 1298 mend = mem->ranges[i].end; 1299 1300 phdr->p_type = PT_LOAD; 1301 phdr->p_flags = PF_R|PF_W|PF_X; 1302 phdr->p_offset = mstart; 1303 1304 phdr->p_paddr = mstart; 1305 phdr->p_vaddr = (unsigned long) __va(mstart); 1306 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; 1307 phdr->p_align = 0; 1308 ehdr->e_phnum++; 1309 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", 1310 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, 1311 ehdr->e_phnum, phdr->p_offset); 1312 phdr++; 1313 } 1314 1315 *addr = buf; 1316 *sz = elf_sz; 1317 return 0; 1318 } 1319