1 /* 2 * kexec: kexec_file_load system call 3 * 4 * Copyright (C) 2014 Red Hat Inc. 5 * Authors: 6 * Vivek Goyal <vgoyal@redhat.com> 7 * 8 * This source code is licensed under the GNU General Public License, 9 * Version 2. See the file COPYING for more details. 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/capability.h> 15 #include <linux/mm.h> 16 #include <linux/file.h> 17 #include <linux/slab.h> 18 #include <linux/kexec.h> 19 #include <linux/mutex.h> 20 #include <linux/list.h> 21 #include <linux/fs.h> 22 #include <linux/ima.h> 23 #include <crypto/hash.h> 24 #include <crypto/sha.h> 25 #include <linux/elf.h> 26 #include <linux/elfcore.h> 27 #include <linux/kernel.h> 28 #include <linux/kexec.h> 29 #include <linux/slab.h> 30 #include <linux/syscalls.h> 31 #include <linux/vmalloc.h> 32 #include "kexec_internal.h" 33 34 static int kexec_calculate_store_digests(struct kimage *image); 35 36 /* 37 * Currently this is the only default function that is exported as some 38 * architectures need it to do additional handlings. 39 * In the future, other default functions may be exported too if required. 40 */ 41 int kexec_image_probe_default(struct kimage *image, void *buf, 42 unsigned long buf_len) 43 { 44 const struct kexec_file_ops * const *fops; 45 int ret = -ENOEXEC; 46 47 for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) { 48 ret = (*fops)->probe(buf, buf_len); 49 if (!ret) { 50 image->fops = *fops; 51 return ret; 52 } 53 } 54 55 return ret; 56 } 57 58 /* Architectures can provide this probe function */ 59 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, 60 unsigned long buf_len) 61 { 62 return kexec_image_probe_default(image, buf, buf_len); 63 } 64 65 static void *kexec_image_load_default(struct kimage *image) 66 { 67 if (!image->fops || !image->fops->load) 68 return ERR_PTR(-ENOEXEC); 69 70 return image->fops->load(image, image->kernel_buf, 71 image->kernel_buf_len, image->initrd_buf, 72 image->initrd_buf_len, image->cmdline_buf, 73 image->cmdline_buf_len); 74 } 75 76 void * __weak arch_kexec_kernel_image_load(struct kimage *image) 77 { 78 return kexec_image_load_default(image); 79 } 80 81 static int kexec_image_post_load_cleanup_default(struct kimage *image) 82 { 83 if (!image->fops || !image->fops->cleanup) 84 return 0; 85 86 return image->fops->cleanup(image->image_loader_data); 87 } 88 89 int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) 90 { 91 return kexec_image_post_load_cleanup_default(image); 92 } 93 94 #ifdef CONFIG_KEXEC_VERIFY_SIG 95 static int kexec_image_verify_sig_default(struct kimage *image, void *buf, 96 unsigned long buf_len) 97 { 98 if (!image->fops || !image->fops->verify_sig) { 99 pr_debug("kernel loader does not support signature verification.\n"); 100 return -EKEYREJECTED; 101 } 102 103 return image->fops->verify_sig(buf, buf_len); 104 } 105 106 int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, 107 unsigned long buf_len) 108 { 109 return kexec_image_verify_sig_default(image, buf, buf_len); 110 } 111 #endif 112 113 /* 114 * arch_kexec_apply_relocations_add - apply relocations of type RELA 115 * @pi: Purgatory to be relocated. 116 * @section: Section relocations applying to. 117 * @relsec: Section containing RELAs. 118 * @symtab: Corresponding symtab. 119 * 120 * Return: 0 on success, negative errno on error. 121 */ 122 int __weak 123 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section, 124 const Elf_Shdr *relsec, const Elf_Shdr *symtab) 125 { 126 pr_err("RELA relocation unsupported.\n"); 127 return -ENOEXEC; 128 } 129 130 /* 131 * arch_kexec_apply_relocations - apply relocations of type REL 132 * @pi: Purgatory to be relocated. 133 * @section: Section relocations applying to. 134 * @relsec: Section containing RELs. 135 * @symtab: Corresponding symtab. 136 * 137 * Return: 0 on success, negative errno on error. 138 */ 139 int __weak 140 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section, 141 const Elf_Shdr *relsec, const Elf_Shdr *symtab) 142 { 143 pr_err("REL relocation unsupported.\n"); 144 return -ENOEXEC; 145 } 146 147 /* 148 * Free up memory used by kernel, initrd, and command line. This is temporary 149 * memory allocation which is not needed any more after these buffers have 150 * been loaded into separate segments and have been copied elsewhere. 151 */ 152 void kimage_file_post_load_cleanup(struct kimage *image) 153 { 154 struct purgatory_info *pi = &image->purgatory_info; 155 156 vfree(image->kernel_buf); 157 image->kernel_buf = NULL; 158 159 vfree(image->initrd_buf); 160 image->initrd_buf = NULL; 161 162 kfree(image->cmdline_buf); 163 image->cmdline_buf = NULL; 164 165 vfree(pi->purgatory_buf); 166 pi->purgatory_buf = NULL; 167 168 vfree(pi->sechdrs); 169 pi->sechdrs = NULL; 170 171 /* See if architecture has anything to cleanup post load */ 172 arch_kimage_file_post_load_cleanup(image); 173 174 /* 175 * Above call should have called into bootloader to free up 176 * any data stored in kimage->image_loader_data. It should 177 * be ok now to free it up. 178 */ 179 kfree(image->image_loader_data); 180 image->image_loader_data = NULL; 181 } 182 183 /* 184 * In file mode list of segments is prepared by kernel. Copy relevant 185 * data from user space, do error checking, prepare segment list 186 */ 187 static int 188 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, 189 const char __user *cmdline_ptr, 190 unsigned long cmdline_len, unsigned flags) 191 { 192 int ret = 0; 193 void *ldata; 194 loff_t size; 195 196 ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, 197 &size, INT_MAX, READING_KEXEC_IMAGE); 198 if (ret) 199 return ret; 200 image->kernel_buf_len = size; 201 202 /* IMA needs to pass the measurement list to the next kernel. */ 203 ima_add_kexec_buffer(image); 204 205 /* Call arch image probe handlers */ 206 ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, 207 image->kernel_buf_len); 208 if (ret) 209 goto out; 210 211 #ifdef CONFIG_KEXEC_VERIFY_SIG 212 ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, 213 image->kernel_buf_len); 214 if (ret) { 215 pr_debug("kernel signature verification failed.\n"); 216 goto out; 217 } 218 pr_debug("kernel signature verification successful.\n"); 219 #endif 220 /* It is possible that there no initramfs is being loaded */ 221 if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { 222 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, 223 &size, INT_MAX, 224 READING_KEXEC_INITRAMFS); 225 if (ret) 226 goto out; 227 image->initrd_buf_len = size; 228 } 229 230 if (cmdline_len) { 231 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len); 232 if (IS_ERR(image->cmdline_buf)) { 233 ret = PTR_ERR(image->cmdline_buf); 234 image->cmdline_buf = NULL; 235 goto out; 236 } 237 238 image->cmdline_buf_len = cmdline_len; 239 240 /* command line should be a string with last byte null */ 241 if (image->cmdline_buf[cmdline_len - 1] != '\0') { 242 ret = -EINVAL; 243 goto out; 244 } 245 } 246 247 /* Call arch image load handlers */ 248 ldata = arch_kexec_kernel_image_load(image); 249 250 if (IS_ERR(ldata)) { 251 ret = PTR_ERR(ldata); 252 goto out; 253 } 254 255 image->image_loader_data = ldata; 256 out: 257 /* In case of error, free up all allocated memory in this function */ 258 if (ret) 259 kimage_file_post_load_cleanup(image); 260 return ret; 261 } 262 263 static int 264 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, 265 int initrd_fd, const char __user *cmdline_ptr, 266 unsigned long cmdline_len, unsigned long flags) 267 { 268 int ret; 269 struct kimage *image; 270 bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; 271 272 image = do_kimage_alloc_init(); 273 if (!image) 274 return -ENOMEM; 275 276 image->file_mode = 1; 277 278 if (kexec_on_panic) { 279 /* Enable special crash kernel control page alloc policy. */ 280 image->control_page = crashk_res.start; 281 image->type = KEXEC_TYPE_CRASH; 282 } 283 284 ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, 285 cmdline_ptr, cmdline_len, flags); 286 if (ret) 287 goto out_free_image; 288 289 ret = sanity_check_segment_list(image); 290 if (ret) 291 goto out_free_post_load_bufs; 292 293 ret = -ENOMEM; 294 image->control_code_page = kimage_alloc_control_pages(image, 295 get_order(KEXEC_CONTROL_PAGE_SIZE)); 296 if (!image->control_code_page) { 297 pr_err("Could not allocate control_code_buffer\n"); 298 goto out_free_post_load_bufs; 299 } 300 301 if (!kexec_on_panic) { 302 image->swap_page = kimage_alloc_control_pages(image, 0); 303 if (!image->swap_page) { 304 pr_err("Could not allocate swap buffer\n"); 305 goto out_free_control_pages; 306 } 307 } 308 309 *rimage = image; 310 return 0; 311 out_free_control_pages: 312 kimage_free_page_list(&image->control_pages); 313 out_free_post_load_bufs: 314 kimage_file_post_load_cleanup(image); 315 out_free_image: 316 kfree(image); 317 return ret; 318 } 319 320 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, 321 unsigned long, cmdline_len, const char __user *, cmdline_ptr, 322 unsigned long, flags) 323 { 324 int ret = 0, i; 325 struct kimage **dest_image, *image; 326 327 /* We only trust the superuser with rebooting the system. */ 328 if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) 329 return -EPERM; 330 331 /* Make sure we have a legal set of flags */ 332 if (flags != (flags & KEXEC_FILE_FLAGS)) 333 return -EINVAL; 334 335 image = NULL; 336 337 if (!mutex_trylock(&kexec_mutex)) 338 return -EBUSY; 339 340 dest_image = &kexec_image; 341 if (flags & KEXEC_FILE_ON_CRASH) { 342 dest_image = &kexec_crash_image; 343 if (kexec_crash_image) 344 arch_kexec_unprotect_crashkres(); 345 } 346 347 if (flags & KEXEC_FILE_UNLOAD) 348 goto exchange; 349 350 /* 351 * In case of crash, new kernel gets loaded in reserved region. It is 352 * same memory where old crash kernel might be loaded. Free any 353 * current crash dump kernel before we corrupt it. 354 */ 355 if (flags & KEXEC_FILE_ON_CRASH) 356 kimage_free(xchg(&kexec_crash_image, NULL)); 357 358 ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, 359 cmdline_len, flags); 360 if (ret) 361 goto out; 362 363 ret = machine_kexec_prepare(image); 364 if (ret) 365 goto out; 366 367 /* 368 * Some architecture(like S390) may touch the crash memory before 369 * machine_kexec_prepare(), we must copy vmcoreinfo data after it. 370 */ 371 ret = kimage_crash_copy_vmcoreinfo(image); 372 if (ret) 373 goto out; 374 375 ret = kexec_calculate_store_digests(image); 376 if (ret) 377 goto out; 378 379 for (i = 0; i < image->nr_segments; i++) { 380 struct kexec_segment *ksegment; 381 382 ksegment = &image->segment[i]; 383 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", 384 i, ksegment->buf, ksegment->bufsz, ksegment->mem, 385 ksegment->memsz); 386 387 ret = kimage_load_segment(image, &image->segment[i]); 388 if (ret) 389 goto out; 390 } 391 392 kimage_terminate(image); 393 394 /* 395 * Free up any temporary buffers allocated which are not needed 396 * after image has been loaded 397 */ 398 kimage_file_post_load_cleanup(image); 399 exchange: 400 image = xchg(dest_image, image); 401 out: 402 if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) 403 arch_kexec_protect_crashkres(); 404 405 mutex_unlock(&kexec_mutex); 406 kimage_free(image); 407 return ret; 408 } 409 410 static int locate_mem_hole_top_down(unsigned long start, unsigned long end, 411 struct kexec_buf *kbuf) 412 { 413 struct kimage *image = kbuf->image; 414 unsigned long temp_start, temp_end; 415 416 temp_end = min(end, kbuf->buf_max); 417 temp_start = temp_end - kbuf->memsz; 418 419 do { 420 /* align down start */ 421 temp_start = temp_start & (~(kbuf->buf_align - 1)); 422 423 if (temp_start < start || temp_start < kbuf->buf_min) 424 return 0; 425 426 temp_end = temp_start + kbuf->memsz - 1; 427 428 /* 429 * Make sure this does not conflict with any of existing 430 * segments 431 */ 432 if (kimage_is_destination_range(image, temp_start, temp_end)) { 433 temp_start = temp_start - PAGE_SIZE; 434 continue; 435 } 436 437 /* We found a suitable memory range */ 438 break; 439 } while (1); 440 441 /* If we are here, we found a suitable memory range */ 442 kbuf->mem = temp_start; 443 444 /* Success, stop navigating through remaining System RAM ranges */ 445 return 1; 446 } 447 448 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, 449 struct kexec_buf *kbuf) 450 { 451 struct kimage *image = kbuf->image; 452 unsigned long temp_start, temp_end; 453 454 temp_start = max(start, kbuf->buf_min); 455 456 do { 457 temp_start = ALIGN(temp_start, kbuf->buf_align); 458 temp_end = temp_start + kbuf->memsz - 1; 459 460 if (temp_end > end || temp_end > kbuf->buf_max) 461 return 0; 462 /* 463 * Make sure this does not conflict with any of existing 464 * segments 465 */ 466 if (kimage_is_destination_range(image, temp_start, temp_end)) { 467 temp_start = temp_start + PAGE_SIZE; 468 continue; 469 } 470 471 /* We found a suitable memory range */ 472 break; 473 } while (1); 474 475 /* If we are here, we found a suitable memory range */ 476 kbuf->mem = temp_start; 477 478 /* Success, stop navigating through remaining System RAM ranges */ 479 return 1; 480 } 481 482 static int locate_mem_hole_callback(struct resource *res, void *arg) 483 { 484 struct kexec_buf *kbuf = (struct kexec_buf *)arg; 485 u64 start = res->start, end = res->end; 486 unsigned long sz = end - start + 1; 487 488 /* Returning 0 will take to next memory range */ 489 if (sz < kbuf->memsz) 490 return 0; 491 492 if (end < kbuf->buf_min || start > kbuf->buf_max) 493 return 0; 494 495 /* 496 * Allocate memory top down with-in ram range. Otherwise bottom up 497 * allocation. 498 */ 499 if (kbuf->top_down) 500 return locate_mem_hole_top_down(start, end, kbuf); 501 return locate_mem_hole_bottom_up(start, end, kbuf); 502 } 503 504 /** 505 * arch_kexec_walk_mem - call func(data) on free memory regions 506 * @kbuf: Context info for the search. Also passed to @func. 507 * @func: Function to call for each memory region. 508 * 509 * Return: The memory walk will stop when func returns a non-zero value 510 * and that value will be returned. If all free regions are visited without 511 * func returning non-zero, then zero will be returned. 512 */ 513 int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf, 514 int (*func)(struct resource *, void *)) 515 { 516 if (kbuf->image->type == KEXEC_TYPE_CRASH) 517 return walk_iomem_res_desc(crashk_res.desc, 518 IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, 519 crashk_res.start, crashk_res.end, 520 kbuf, func); 521 else 522 return walk_system_ram_res(0, ULONG_MAX, kbuf, func); 523 } 524 525 /** 526 * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel 527 * @kbuf: Parameters for the memory search. 528 * 529 * On success, kbuf->mem will have the start address of the memory region found. 530 * 531 * Return: 0 on success, negative errno on error. 532 */ 533 int kexec_locate_mem_hole(struct kexec_buf *kbuf) 534 { 535 int ret; 536 537 ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback); 538 539 return ret == 1 ? 0 : -EADDRNOTAVAIL; 540 } 541 542 /** 543 * kexec_add_buffer - place a buffer in a kexec segment 544 * @kbuf: Buffer contents and memory parameters. 545 * 546 * This function assumes that kexec_mutex is held. 547 * On successful return, @kbuf->mem will have the physical address of 548 * the buffer in memory. 549 * 550 * Return: 0 on success, negative errno on error. 551 */ 552 int kexec_add_buffer(struct kexec_buf *kbuf) 553 { 554 555 struct kexec_segment *ksegment; 556 int ret; 557 558 /* Currently adding segment this way is allowed only in file mode */ 559 if (!kbuf->image->file_mode) 560 return -EINVAL; 561 562 if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) 563 return -EINVAL; 564 565 /* 566 * Make sure we are not trying to add buffer after allocating 567 * control pages. All segments need to be placed first before 568 * any control pages are allocated. As control page allocation 569 * logic goes through list of segments to make sure there are 570 * no destination overlaps. 571 */ 572 if (!list_empty(&kbuf->image->control_pages)) { 573 WARN_ON(1); 574 return -EINVAL; 575 } 576 577 /* Ensure minimum alignment needed for segments. */ 578 kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); 579 kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); 580 581 /* Walk the RAM ranges and allocate a suitable range for the buffer */ 582 ret = kexec_locate_mem_hole(kbuf); 583 if (ret) 584 return ret; 585 586 /* Found a suitable memory range */ 587 ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; 588 ksegment->kbuf = kbuf->buffer; 589 ksegment->bufsz = kbuf->bufsz; 590 ksegment->mem = kbuf->mem; 591 ksegment->memsz = kbuf->memsz; 592 kbuf->image->nr_segments++; 593 return 0; 594 } 595 596 /* Calculate and store the digest of segments */ 597 static int kexec_calculate_store_digests(struct kimage *image) 598 { 599 struct crypto_shash *tfm; 600 struct shash_desc *desc; 601 int ret = 0, i, j, zero_buf_sz, sha_region_sz; 602 size_t desc_size, nullsz; 603 char *digest; 604 void *zero_buf; 605 struct kexec_sha_region *sha_regions; 606 struct purgatory_info *pi = &image->purgatory_info; 607 608 if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY)) 609 return 0; 610 611 zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); 612 zero_buf_sz = PAGE_SIZE; 613 614 tfm = crypto_alloc_shash("sha256", 0, 0); 615 if (IS_ERR(tfm)) { 616 ret = PTR_ERR(tfm); 617 goto out; 618 } 619 620 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); 621 desc = kzalloc(desc_size, GFP_KERNEL); 622 if (!desc) { 623 ret = -ENOMEM; 624 goto out_free_tfm; 625 } 626 627 sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); 628 sha_regions = vzalloc(sha_region_sz); 629 if (!sha_regions) 630 goto out_free_desc; 631 632 desc->tfm = tfm; 633 desc->flags = 0; 634 635 ret = crypto_shash_init(desc); 636 if (ret < 0) 637 goto out_free_sha_regions; 638 639 digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); 640 if (!digest) { 641 ret = -ENOMEM; 642 goto out_free_sha_regions; 643 } 644 645 for (j = i = 0; i < image->nr_segments; i++) { 646 struct kexec_segment *ksegment; 647 648 ksegment = &image->segment[i]; 649 /* 650 * Skip purgatory as it will be modified once we put digest 651 * info in purgatory. 652 */ 653 if (ksegment->kbuf == pi->purgatory_buf) 654 continue; 655 656 ret = crypto_shash_update(desc, ksegment->kbuf, 657 ksegment->bufsz); 658 if (ret) 659 break; 660 661 /* 662 * Assume rest of the buffer is filled with zero and 663 * update digest accordingly. 664 */ 665 nullsz = ksegment->memsz - ksegment->bufsz; 666 while (nullsz) { 667 unsigned long bytes = nullsz; 668 669 if (bytes > zero_buf_sz) 670 bytes = zero_buf_sz; 671 ret = crypto_shash_update(desc, zero_buf, bytes); 672 if (ret) 673 break; 674 nullsz -= bytes; 675 } 676 677 if (ret) 678 break; 679 680 sha_regions[j].start = ksegment->mem; 681 sha_regions[j].len = ksegment->memsz; 682 j++; 683 } 684 685 if (!ret) { 686 ret = crypto_shash_final(desc, digest); 687 if (ret) 688 goto out_free_digest; 689 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", 690 sha_regions, sha_region_sz, 0); 691 if (ret) 692 goto out_free_digest; 693 694 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", 695 digest, SHA256_DIGEST_SIZE, 0); 696 if (ret) 697 goto out_free_digest; 698 } 699 700 out_free_digest: 701 kfree(digest); 702 out_free_sha_regions: 703 vfree(sha_regions); 704 out_free_desc: 705 kfree(desc); 706 out_free_tfm: 707 kfree(tfm); 708 out: 709 return ret; 710 } 711 712 #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY 713 /* 714 * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. 715 * @pi: Purgatory to be loaded. 716 * @kbuf: Buffer to setup. 717 * 718 * Allocates the memory needed for the buffer. Caller is responsible to free 719 * the memory after use. 720 * 721 * Return: 0 on success, negative errno on error. 722 */ 723 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, 724 struct kexec_buf *kbuf) 725 { 726 const Elf_Shdr *sechdrs; 727 unsigned long bss_align; 728 unsigned long bss_sz; 729 unsigned long align; 730 int i, ret; 731 732 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 733 kbuf->buf_align = bss_align = 1; 734 kbuf->bufsz = bss_sz = 0; 735 736 for (i = 0; i < pi->ehdr->e_shnum; i++) { 737 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 738 continue; 739 740 align = sechdrs[i].sh_addralign; 741 if (sechdrs[i].sh_type != SHT_NOBITS) { 742 if (kbuf->buf_align < align) 743 kbuf->buf_align = align; 744 kbuf->bufsz = ALIGN(kbuf->bufsz, align); 745 kbuf->bufsz += sechdrs[i].sh_size; 746 } else { 747 if (bss_align < align) 748 bss_align = align; 749 bss_sz = ALIGN(bss_sz, align); 750 bss_sz += sechdrs[i].sh_size; 751 } 752 } 753 kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); 754 kbuf->memsz = kbuf->bufsz + bss_sz; 755 if (kbuf->buf_align < bss_align) 756 kbuf->buf_align = bss_align; 757 758 kbuf->buffer = vzalloc(kbuf->bufsz); 759 if (!kbuf->buffer) 760 return -ENOMEM; 761 pi->purgatory_buf = kbuf->buffer; 762 763 ret = kexec_add_buffer(kbuf); 764 if (ret) 765 goto out; 766 767 return 0; 768 out: 769 vfree(pi->purgatory_buf); 770 pi->purgatory_buf = NULL; 771 return ret; 772 } 773 774 /* 775 * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. 776 * @pi: Purgatory to be loaded. 777 * @kbuf: Buffer prepared to store purgatory. 778 * 779 * Allocates the memory needed for the buffer. Caller is responsible to free 780 * the memory after use. 781 * 782 * Return: 0 on success, negative errno on error. 783 */ 784 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, 785 struct kexec_buf *kbuf) 786 { 787 unsigned long bss_addr; 788 unsigned long offset; 789 Elf_Shdr *sechdrs; 790 int i; 791 792 /* 793 * The section headers in kexec_purgatory are read-only. In order to 794 * have them modifiable make a temporary copy. 795 */ 796 sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum)); 797 if (!sechdrs) 798 return -ENOMEM; 799 memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, 800 pi->ehdr->e_shnum * sizeof(Elf_Shdr)); 801 pi->sechdrs = sechdrs; 802 803 offset = 0; 804 bss_addr = kbuf->mem + kbuf->bufsz; 805 kbuf->image->start = pi->ehdr->e_entry; 806 807 for (i = 0; i < pi->ehdr->e_shnum; i++) { 808 unsigned long align; 809 void *src, *dst; 810 811 if (!(sechdrs[i].sh_flags & SHF_ALLOC)) 812 continue; 813 814 align = sechdrs[i].sh_addralign; 815 if (sechdrs[i].sh_type == SHT_NOBITS) { 816 bss_addr = ALIGN(bss_addr, align); 817 sechdrs[i].sh_addr = bss_addr; 818 bss_addr += sechdrs[i].sh_size; 819 continue; 820 } 821 822 offset = ALIGN(offset, align); 823 if (sechdrs[i].sh_flags & SHF_EXECINSTR && 824 pi->ehdr->e_entry >= sechdrs[i].sh_addr && 825 pi->ehdr->e_entry < (sechdrs[i].sh_addr 826 + sechdrs[i].sh_size)) { 827 kbuf->image->start -= sechdrs[i].sh_addr; 828 kbuf->image->start += kbuf->mem + offset; 829 } 830 831 src = (void *)pi->ehdr + sechdrs[i].sh_offset; 832 dst = pi->purgatory_buf + offset; 833 memcpy(dst, src, sechdrs[i].sh_size); 834 835 sechdrs[i].sh_addr = kbuf->mem + offset; 836 sechdrs[i].sh_offset = offset; 837 offset += sechdrs[i].sh_size; 838 } 839 840 return 0; 841 } 842 843 static int kexec_apply_relocations(struct kimage *image) 844 { 845 int i, ret; 846 struct purgatory_info *pi = &image->purgatory_info; 847 const Elf_Shdr *sechdrs; 848 849 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; 850 851 for (i = 0; i < pi->ehdr->e_shnum; i++) { 852 const Elf_Shdr *relsec; 853 const Elf_Shdr *symtab; 854 Elf_Shdr *section; 855 856 relsec = sechdrs + i; 857 858 if (relsec->sh_type != SHT_RELA && 859 relsec->sh_type != SHT_REL) 860 continue; 861 862 /* 863 * For section of type SHT_RELA/SHT_REL, 864 * ->sh_link contains section header index of associated 865 * symbol table. And ->sh_info contains section header 866 * index of section to which relocations apply. 867 */ 868 if (relsec->sh_info >= pi->ehdr->e_shnum || 869 relsec->sh_link >= pi->ehdr->e_shnum) 870 return -ENOEXEC; 871 872 section = pi->sechdrs + relsec->sh_info; 873 symtab = sechdrs + relsec->sh_link; 874 875 if (!(section->sh_flags & SHF_ALLOC)) 876 continue; 877 878 /* 879 * symtab->sh_link contain section header index of associated 880 * string table. 881 */ 882 if (symtab->sh_link >= pi->ehdr->e_shnum) 883 /* Invalid section number? */ 884 continue; 885 886 /* 887 * Respective architecture needs to provide support for applying 888 * relocations of type SHT_RELA/SHT_REL. 889 */ 890 if (relsec->sh_type == SHT_RELA) 891 ret = arch_kexec_apply_relocations_add(pi, section, 892 relsec, symtab); 893 else if (relsec->sh_type == SHT_REL) 894 ret = arch_kexec_apply_relocations(pi, section, 895 relsec, symtab); 896 if (ret) 897 return ret; 898 } 899 900 return 0; 901 } 902 903 /* 904 * kexec_load_purgatory - Load and relocate the purgatory object. 905 * @image: Image to add the purgatory to. 906 * @kbuf: Memory parameters to use. 907 * 908 * Allocates the memory needed for image->purgatory_info.sechdrs and 909 * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible 910 * to free the memory after use. 911 * 912 * Return: 0 on success, negative errno on error. 913 */ 914 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) 915 { 916 struct purgatory_info *pi = &image->purgatory_info; 917 int ret; 918 919 if (kexec_purgatory_size <= 0) 920 return -EINVAL; 921 922 pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; 923 924 ret = kexec_purgatory_setup_kbuf(pi, kbuf); 925 if (ret) 926 return ret; 927 928 ret = kexec_purgatory_setup_sechdrs(pi, kbuf); 929 if (ret) 930 goto out_free_kbuf; 931 932 ret = kexec_apply_relocations(image); 933 if (ret) 934 goto out; 935 936 return 0; 937 out: 938 vfree(pi->sechdrs); 939 pi->sechdrs = NULL; 940 out_free_kbuf: 941 vfree(pi->purgatory_buf); 942 pi->purgatory_buf = NULL; 943 return ret; 944 } 945 946 /* 947 * kexec_purgatory_find_symbol - find a symbol in the purgatory 948 * @pi: Purgatory to search in. 949 * @name: Name of the symbol. 950 * 951 * Return: pointer to symbol in read-only symtab on success, NULL on error. 952 */ 953 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 954 const char *name) 955 { 956 const Elf_Shdr *sechdrs; 957 const Elf_Ehdr *ehdr; 958 const Elf_Sym *syms; 959 const char *strtab; 960 int i, k; 961 962 if (!pi->ehdr) 963 return NULL; 964 965 ehdr = pi->ehdr; 966 sechdrs = (void *)ehdr + ehdr->e_shoff; 967 968 for (i = 0; i < ehdr->e_shnum; i++) { 969 if (sechdrs[i].sh_type != SHT_SYMTAB) 970 continue; 971 972 if (sechdrs[i].sh_link >= ehdr->e_shnum) 973 /* Invalid strtab section number */ 974 continue; 975 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; 976 syms = (void *)ehdr + sechdrs[i].sh_offset; 977 978 /* Go through symbols for a match */ 979 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { 980 if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) 981 continue; 982 983 if (strcmp(strtab + syms[k].st_name, name) != 0) 984 continue; 985 986 if (syms[k].st_shndx == SHN_UNDEF || 987 syms[k].st_shndx >= ehdr->e_shnum) { 988 pr_debug("Symbol: %s has bad section index %d.\n", 989 name, syms[k].st_shndx); 990 return NULL; 991 } 992 993 /* Found the symbol we are looking for */ 994 return &syms[k]; 995 } 996 } 997 998 return NULL; 999 } 1000 1001 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) 1002 { 1003 struct purgatory_info *pi = &image->purgatory_info; 1004 const Elf_Sym *sym; 1005 Elf_Shdr *sechdr; 1006 1007 sym = kexec_purgatory_find_symbol(pi, name); 1008 if (!sym) 1009 return ERR_PTR(-EINVAL); 1010 1011 sechdr = &pi->sechdrs[sym->st_shndx]; 1012 1013 /* 1014 * Returns the address where symbol will finally be loaded after 1015 * kexec_load_segment() 1016 */ 1017 return (void *)(sechdr->sh_addr + sym->st_value); 1018 } 1019 1020 /* 1021 * Get or set value of a symbol. If "get_value" is true, symbol value is 1022 * returned in buf otherwise symbol value is set based on value in buf. 1023 */ 1024 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 1025 void *buf, unsigned int size, bool get_value) 1026 { 1027 struct purgatory_info *pi = &image->purgatory_info; 1028 const Elf_Sym *sym; 1029 Elf_Shdr *sec; 1030 char *sym_buf; 1031 1032 sym = kexec_purgatory_find_symbol(pi, name); 1033 if (!sym) 1034 return -EINVAL; 1035 1036 if (sym->st_size != size) { 1037 pr_err("symbol %s size mismatch: expected %lu actual %u\n", 1038 name, (unsigned long)sym->st_size, size); 1039 return -EINVAL; 1040 } 1041 1042 sec = pi->sechdrs + sym->st_shndx; 1043 1044 if (sec->sh_type == SHT_NOBITS) { 1045 pr_err("symbol %s is in a bss section. Cannot %s\n", name, 1046 get_value ? "get" : "set"); 1047 return -EINVAL; 1048 } 1049 1050 sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; 1051 1052 if (get_value) 1053 memcpy((void *)buf, sym_buf, size); 1054 else 1055 memcpy((void *)sym_buf, buf, size); 1056 1057 return 0; 1058 } 1059 #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */ 1060 1061 int crash_exclude_mem_range(struct crash_mem *mem, 1062 unsigned long long mstart, unsigned long long mend) 1063 { 1064 int i, j; 1065 unsigned long long start, end; 1066 struct crash_mem_range temp_range = {0, 0}; 1067 1068 for (i = 0; i < mem->nr_ranges; i++) { 1069 start = mem->ranges[i].start; 1070 end = mem->ranges[i].end; 1071 1072 if (mstart > end || mend < start) 1073 continue; 1074 1075 /* Truncate any area outside of range */ 1076 if (mstart < start) 1077 mstart = start; 1078 if (mend > end) 1079 mend = end; 1080 1081 /* Found completely overlapping range */ 1082 if (mstart == start && mend == end) { 1083 mem->ranges[i].start = 0; 1084 mem->ranges[i].end = 0; 1085 if (i < mem->nr_ranges - 1) { 1086 /* Shift rest of the ranges to left */ 1087 for (j = i; j < mem->nr_ranges - 1; j++) { 1088 mem->ranges[j].start = 1089 mem->ranges[j+1].start; 1090 mem->ranges[j].end = 1091 mem->ranges[j+1].end; 1092 } 1093 } 1094 mem->nr_ranges--; 1095 return 0; 1096 } 1097 1098 if (mstart > start && mend < end) { 1099 /* Split original range */ 1100 mem->ranges[i].end = mstart - 1; 1101 temp_range.start = mend + 1; 1102 temp_range.end = end; 1103 } else if (mstart != start) 1104 mem->ranges[i].end = mstart - 1; 1105 else 1106 mem->ranges[i].start = mend + 1; 1107 break; 1108 } 1109 1110 /* If a split happened, add the split to array */ 1111 if (!temp_range.end) 1112 return 0; 1113 1114 /* Split happened */ 1115 if (i == mem->max_nr_ranges - 1) 1116 return -ENOMEM; 1117 1118 /* Location where new range should go */ 1119 j = i + 1; 1120 if (j < mem->nr_ranges) { 1121 /* Move over all ranges one slot towards the end */ 1122 for (i = mem->nr_ranges - 1; i >= j; i--) 1123 mem->ranges[i + 1] = mem->ranges[i]; 1124 } 1125 1126 mem->ranges[j].start = temp_range.start; 1127 mem->ranges[j].end = temp_range.end; 1128 mem->nr_ranges++; 1129 return 0; 1130 } 1131 1132 int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, 1133 void **addr, unsigned long *sz) 1134 { 1135 Elf64_Ehdr *ehdr; 1136 Elf64_Phdr *phdr; 1137 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; 1138 unsigned char *buf; 1139 unsigned int cpu, i; 1140 unsigned long long notes_addr; 1141 unsigned long mstart, mend; 1142 1143 /* extra phdr for vmcoreinfo elf note */ 1144 nr_phdr = nr_cpus + 1; 1145 nr_phdr += mem->nr_ranges; 1146 1147 /* 1148 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping 1149 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). 1150 * I think this is required by tools like gdb. So same physical 1151 * memory will be mapped in two elf headers. One will contain kernel 1152 * text virtual addresses and other will have __va(physical) addresses. 1153 */ 1154 1155 nr_phdr++; 1156 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); 1157 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); 1158 1159 buf = vzalloc(elf_sz); 1160 if (!buf) 1161 return -ENOMEM; 1162 1163 ehdr = (Elf64_Ehdr *)buf; 1164 phdr = (Elf64_Phdr *)(ehdr + 1); 1165 memcpy(ehdr->e_ident, ELFMAG, SELFMAG); 1166 ehdr->e_ident[EI_CLASS] = ELFCLASS64; 1167 ehdr->e_ident[EI_DATA] = ELFDATA2LSB; 1168 ehdr->e_ident[EI_VERSION] = EV_CURRENT; 1169 ehdr->e_ident[EI_OSABI] = ELF_OSABI; 1170 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); 1171 ehdr->e_type = ET_CORE; 1172 ehdr->e_machine = ELF_ARCH; 1173 ehdr->e_version = EV_CURRENT; 1174 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1175 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1176 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1177 1178 /* Prepare one phdr of type PT_NOTE for each present cpu */ 1179 for_each_present_cpu(cpu) { 1180 phdr->p_type = PT_NOTE; 1181 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); 1182 phdr->p_offset = phdr->p_paddr = notes_addr; 1183 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); 1184 (ehdr->e_phnum)++; 1185 phdr++; 1186 } 1187 1188 /* Prepare one PT_NOTE header for vmcoreinfo */ 1189 phdr->p_type = PT_NOTE; 1190 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); 1191 phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; 1192 (ehdr->e_phnum)++; 1193 phdr++; 1194 1195 /* Prepare PT_LOAD type program header for kernel text region */ 1196 if (kernel_map) { 1197 phdr->p_type = PT_LOAD; 1198 phdr->p_flags = PF_R|PF_W|PF_X; 1199 phdr->p_vaddr = (Elf64_Addr)_text; 1200 phdr->p_filesz = phdr->p_memsz = _end - _text; 1201 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); 1202 ehdr->e_phnum++; 1203 phdr++; 1204 } 1205 1206 /* Go through all the ranges in mem->ranges[] and prepare phdr */ 1207 for (i = 0; i < mem->nr_ranges; i++) { 1208 mstart = mem->ranges[i].start; 1209 mend = mem->ranges[i].end; 1210 1211 phdr->p_type = PT_LOAD; 1212 phdr->p_flags = PF_R|PF_W|PF_X; 1213 phdr->p_offset = mstart; 1214 1215 phdr->p_paddr = mstart; 1216 phdr->p_vaddr = (unsigned long long) __va(mstart); 1217 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; 1218 phdr->p_align = 0; 1219 ehdr->e_phnum++; 1220 phdr++; 1221 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", 1222 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, 1223 ehdr->e_phnum, phdr->p_offset); 1224 } 1225 1226 *addr = buf; 1227 *sz = elf_sz; 1228 return 0; 1229 } 1230