kernel/kexec_file.c

   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         bss_align = 1;
 734         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         pi->purgatory_load_addr = kbuf->mem;
 767
 768         return 0;
 769 out:
 770         vfree(pi->purgatory_buf);
 771         pi->purgatory_buf = NULL;
 772         return ret;
 773 }
 774
 775 /*
 776  * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
 777  * @pi:         Purgatory to be loaded.
 778  * @kbuf:       Buffer prepared to store purgatory.
 779  *
 780  * Allocates the memory needed for the buffer. Caller is responsible to free
 781  * the memory after use.
 782  *
 783  * Return: 0 on success, negative errno on error.
 784  */
 785 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 786                                          struct kexec_buf *kbuf)
 787 {
 788         unsigned long curr_load_addr;
 789         unsigned long load_addr;
 790         unsigned long bss_addr;
 791         unsigned long offset;
 792         unsigned char *buf_addr;
 793         unsigned char *src;
 794         Elf_Shdr *sechdrs;
 795         int entry_sidx = -1;
 796         int i;
 797
 798         sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
 799         if (!sechdrs)
 800                 return -ENOMEM;
 801         memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
 802                pi->ehdr->e_shnum * sizeof(Elf_Shdr));
 803         pi->sechdrs = sechdrs;
 804
 805         /*
 806          * We seem to have multiple copies of sections. First copy is which
 807          * is embedded in kernel in read only section. Some of these sections
 808          * will be copied to a temporary buffer and relocated. And these
 809          * sections will finally be copied to their final destination at
 810          * segment load time.
 811          *
 812          * Use ->sh_offset to reflect section address in memory. It will
 813          * point to original read only copy if section is not allocatable.
 814          * Otherwise it will point to temporary copy which will be relocated.
 815          *
 816          * Use ->sh_addr to contain final address of the section where it
 817          * will go during execution time.
 818          */
 819         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 820                 if (sechdrs[i].sh_type == SHT_NOBITS)
 821                         continue;
 822
 823                 sechdrs[i].sh_offset = (unsigned long)pi->ehdr +
 824                                                 sechdrs[i].sh_offset;
 825         }
 826
 827         /*
 828          * Identify entry point section and make entry relative to section
 829          * start.
 830          */
 831         kbuf->image->start = pi->ehdr->e_entry;
 832         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 833                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 834                         continue;
 835
 836                 if (!(sechdrs[i].sh_flags & SHF_EXECINSTR))
 837                         continue;
 838
 839                 /* Make entry section relative */
 840                 if (sechdrs[i].sh_addr <= pi->ehdr->e_entry &&
 841                     ((sechdrs[i].sh_addr + sechdrs[i].sh_size) >
 842                      pi->ehdr->e_entry)) {
 843                         entry_sidx = i;
 844                         kbuf->image->start -= sechdrs[i].sh_addr;
 845                         break;
 846                 }
 847         }
 848
 849         /* Load SHF_ALLOC sections */
 850         buf_addr = kbuf->buffer;
 851         load_addr = curr_load_addr = kbuf->mem;
 852         bss_addr = load_addr + kbuf->bufsz;
 853
 854         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 855                 unsigned long align;
 856
 857                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 858                         continue;
 859
 860                 align = sechdrs[i].sh_addralign;
 861                 if (sechdrs[i].sh_type != SHT_NOBITS) {
 862                         curr_load_addr = ALIGN(curr_load_addr, align);
 863                         offset = curr_load_addr - load_addr;
 864                         /* We already modifed ->sh_offset to keep src addr */
 865                         src = (char *) sechdrs[i].sh_offset;
 866                         memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
 867
 868                         /* Store load address and source address of section */
 869                         sechdrs[i].sh_addr = curr_load_addr;
 870
 871                         /*
 872                          * This section got copied to temporary buffer. Update
 873                          * ->sh_offset accordingly.
 874                          */
 875                         sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
 876
 877                         /* Advance to the next address */
 878                         curr_load_addr += sechdrs[i].sh_size;
 879                 } else {
 880                         bss_addr = ALIGN(bss_addr, align);
 881                         sechdrs[i].sh_addr = bss_addr;
 882                         bss_addr += sechdrs[i].sh_size;
 883                 }
 884         }
 885
 886         /* Update entry point based on load address of text section */
 887         if (entry_sidx >= 0)
 888                 kbuf->image->start += sechdrs[entry_sidx].sh_addr;
 889
 890         return 0;
 891 }
 892
 893 static int kexec_apply_relocations(struct kimage *image)
 894 {
 895         int i, ret;
 896         struct purgatory_info *pi = &image->purgatory_info;
 897         const Elf_Shdr *sechdrs;
 898
 899         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 900
 901         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 902                 const Elf_Shdr *relsec;
 903                 const Elf_Shdr *symtab;
 904                 Elf_Shdr *section;
 905
 906                 relsec = sechdrs + i;
 907
 908                 if (relsec->sh_type != SHT_RELA &&
 909                     relsec->sh_type != SHT_REL)
 910                         continue;
 911
 912                 /*
 913                  * For section of type SHT_RELA/SHT_REL,
 914                  * ->sh_link contains section header index of associated
 915                  * symbol table. And ->sh_info contains section header
 916                  * index of section to which relocations apply.
 917                  */
 918                 if (relsec->sh_info >= pi->ehdr->e_shnum ||
 919                     relsec->sh_link >= pi->ehdr->e_shnum)
 920                         return -ENOEXEC;
 921
 922                 section = pi->sechdrs + relsec->sh_info;
 923                 symtab = sechdrs + relsec->sh_link;
 924
 925                 if (!(section->sh_flags & SHF_ALLOC))
 926                         continue;
 927
 928                 /*
 929                  * symtab->sh_link contain section header index of associated
 930                  * string table.
 931                  */
 932                 if (symtab->sh_link >= pi->ehdr->e_shnum)
 933                         /* Invalid section number? */
 934                         continue;
 935
 936                 /*
 937                  * Respective architecture needs to provide support for applying
 938                  * relocations of type SHT_RELA/SHT_REL.
 939                  */
 940                 if (relsec->sh_type == SHT_RELA)
 941                         ret = arch_kexec_apply_relocations_add(pi, section,
 942                                                                relsec, symtab);
 943                 else if (relsec->sh_type == SHT_REL)
 944                         ret = arch_kexec_apply_relocations(pi, section,
 945                                                            relsec, symtab);
 946                 if (ret)
 947                         return ret;
 948         }
 949
 950         return 0;
 951 }
 952
 953 /* Load relocatable purgatory object and relocate it appropriately */
 954 int kexec_load_purgatory(struct kimage *image, unsigned long min,
 955                          unsigned long max, int top_down,
 956                          unsigned long *load_addr)
 957 {
 958         struct purgatory_info *pi = &image->purgatory_info;
 959         int ret;
 960         struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1,
 961                                   .buf_min = min, .buf_max = max,
 962                                   .top_down = top_down };
 963
 964         if (kexec_purgatory_size <= 0)
 965                 return -EINVAL;
 966
 967         pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
 968
 969         ret = kexec_purgatory_setup_kbuf(pi, &kbuf);
 970         if (ret)
 971                 return ret;
 972
 973         ret = kexec_purgatory_setup_sechdrs(pi, &kbuf);
 974         if (ret)
 975                 goto out_free_kbuf;
 976
 977         ret = kexec_apply_relocations(image);
 978         if (ret)
 979                 goto out;
 980
 981         *load_addr = pi->purgatory_load_addr;
 982         return 0;
 983 out:
 984         vfree(pi->sechdrs);
 985         pi->sechdrs = NULL;
 986 out_free_kbuf:
 987         vfree(pi->purgatory_buf);
 988         pi->purgatory_buf = NULL;
 989         return ret;
 990 }
 991
 992 /*
 993  * kexec_purgatory_find_symbol - find a symbol in the purgatory
 994  * @pi:         Purgatory to search in.
 995  * @name:       Name of the symbol.
 996  *
 997  * Return: pointer to symbol in read-only symtab on success, NULL on error.
 998  */
 999 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1000                                                   const char *name)
1001 {
1002         const Elf_Shdr *sechdrs;
1003         const Elf_Ehdr *ehdr;
1004         const Elf_Sym *syms;
1005         const char *strtab;
1006         int i, k;
1007
1008         if (!pi->ehdr)
1009                 return NULL;
1010
1011         ehdr = pi->ehdr;
1012         sechdrs = (void *)ehdr + ehdr->e_shoff;
1013
1014         for (i = 0; i < ehdr->e_shnum; i++) {
1015                 if (sechdrs[i].sh_type != SHT_SYMTAB)
1016                         continue;
1017
1018                 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1019                         /* Invalid strtab section number */
1020                         continue;
1021                 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1022                 syms = (void *)ehdr + sechdrs[i].sh_offset;
1023
1024                 /* Go through symbols for a match */
1025                 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1026                         if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1027                                 continue;
1028
1029                         if (strcmp(strtab + syms[k].st_name, name) != 0)
1030                                 continue;
1031
1032                         if (syms[k].st_shndx == SHN_UNDEF ||
1033                             syms[k].st_shndx >= ehdr->e_shnum) {
1034                                 pr_debug("Symbol: %s has bad section index %d.\n",
1035                                                 name, syms[k].st_shndx);
1036                                 return NULL;
1037                         }
1038
1039                         /* Found the symbol we are looking for */
1040                         return &syms[k];
1041                 }
1042         }
1043
1044         return NULL;
1045 }
1046
1047 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1048 {
1049         struct purgatory_info *pi = &image->purgatory_info;
1050         const Elf_Sym *sym;
1051         Elf_Shdr *sechdr;
1052
1053         sym = kexec_purgatory_find_symbol(pi, name);
1054         if (!sym)
1055                 return ERR_PTR(-EINVAL);
1056
1057         sechdr = &pi->sechdrs[sym->st_shndx];
1058
1059         /*
1060          * Returns the address where symbol will finally be loaded after
1061          * kexec_load_segment()
1062          */
1063         return (void *)(sechdr->sh_addr + sym->st_value);
1064 }
1065
1066 /*
1067  * Get or set value of a symbol. If "get_value" is true, symbol value is
1068  * returned in buf otherwise symbol value is set based on value in buf.
1069  */
1070 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1071                                    void *buf, unsigned int size, bool get_value)
1072 {
1073         struct purgatory_info *pi = &image->purgatory_info;
1074         const Elf_Sym *sym;
1075         Elf_Shdr *sec;
1076         char *sym_buf;
1077
1078         sym = kexec_purgatory_find_symbol(pi, name);
1079         if (!sym)
1080                 return -EINVAL;
1081
1082         if (sym->st_size != size) {
1083                 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1084                        name, (unsigned long)sym->st_size, size);
1085                 return -EINVAL;
1086         }
1087
1088         sec = pi->sechdrs + sym->st_shndx;
1089
1090         if (sec->sh_type == SHT_NOBITS) {
1091                 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1092                        get_value ? "get" : "set");
1093                 return -EINVAL;
1094         }
1095
1096         sym_buf = (char *)sec->sh_offset + sym->st_value;
1097
1098         if (get_value)
1099                 memcpy((void *)buf, sym_buf, size);
1100         else
1101                 memcpy((void *)sym_buf, buf, size);
1102
1103         return 0;
1104 }
1105 #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1106
1107 int crash_exclude_mem_range(struct crash_mem *mem,
1108                             unsigned long long mstart, unsigned long long mend)
1109 {
1110         int i, j;
1111         unsigned long long start, end;
1112         struct crash_mem_range temp_range = {0, 0};
1113
1114         for (i = 0; i < mem->nr_ranges; i++) {
1115                 start = mem->ranges[i].start;
1116                 end = mem->ranges[i].end;
1117
1118                 if (mstart > end || mend < start)
1119                         continue;
1120
1121                 /* Truncate any area outside of range */
1122                 if (mstart < start)
1123                         mstart = start;
1124                 if (mend > end)
1125                         mend = end;
1126
1127                 /* Found completely overlapping range */
1128                 if (mstart == start && mend == end) {
1129                         mem->ranges[i].start = 0;
1130                         mem->ranges[i].end = 0;
1131                         if (i < mem->nr_ranges - 1) {
1132                                 /* Shift rest of the ranges to left */
1133                                 for (j = i; j < mem->nr_ranges - 1; j++) {
1134                                         mem->ranges[j].start =
1135                                                 mem->ranges[j+1].start;
1136                                         mem->ranges[j].end =
1137                                                         mem->ranges[j+1].end;
1138                                 }
1139                         }
1140                         mem->nr_ranges--;
1141                         return 0;
1142                 }
1143
1144                 if (mstart > start && mend < end) {
1145                         /* Split original range */
1146                         mem->ranges[i].end = mstart - 1;
1147                         temp_range.start = mend + 1;
1148                         temp_range.end = end;
1149                 } else if (mstart != start)
1150                         mem->ranges[i].end = mstart - 1;
1151                 else
1152                         mem->ranges[i].start = mend + 1;
1153                 break;
1154         }
1155
1156         /* If a split happened, add the split to array */
1157         if (!temp_range.end)
1158                 return 0;
1159
1160         /* Split happened */
1161         if (i == mem->max_nr_ranges - 1)
1162                 return -ENOMEM;
1163
1164         /* Location where new range should go */
1165         j = i + 1;
1166         if (j < mem->nr_ranges) {
1167                 /* Move over all ranges one slot towards the end */
1168                 for (i = mem->nr_ranges - 1; i >= j; i--)
1169                         mem->ranges[i + 1] = mem->ranges[i];
1170         }
1171
1172         mem->ranges[j].start = temp_range.start;
1173         mem->ranges[j].end = temp_range.end;
1174         mem->nr_ranges++;
1175         return 0;
1176 }
1177
1178 int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1179                           void **addr, unsigned long *sz)
1180 {
1181         Elf64_Ehdr *ehdr;
1182         Elf64_Phdr *phdr;
1183         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1184         unsigned char *buf;
1185         unsigned int cpu, i;
1186         unsigned long long notes_addr;
1187         unsigned long mstart, mend;
1188
1189         /* extra phdr for vmcoreinfo elf note */
1190         nr_phdr = nr_cpus + 1;
1191         nr_phdr += mem->nr_ranges;
1192
1193         /*
1194          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1195          * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1196          * I think this is required by tools like gdb. So same physical
1197          * memory will be mapped in two elf headers. One will contain kernel
1198          * text virtual addresses and other will have __va(physical) addresses.
1199          */
1200
1201         nr_phdr++;
1202         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1203         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1204
1205         buf = vzalloc(elf_sz);
1206         if (!buf)
1207                 return -ENOMEM;
1208
1209         ehdr = (Elf64_Ehdr *)buf;
1210         phdr = (Elf64_Phdr *)(ehdr + 1);
1211         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1212         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1213         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1214         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1215         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1216         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1217         ehdr->e_type = ET_CORE;
1218         ehdr->e_machine = ELF_ARCH;
1219         ehdr->e_version = EV_CURRENT;
1220         ehdr->e_phoff = sizeof(Elf64_Ehdr);
1221         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1222         ehdr->e_phentsize = sizeof(Elf64_Phdr);
1223
1224         /* Prepare one phdr of type PT_NOTE for each present cpu */
1225         for_each_present_cpu(cpu) {
1226                 phdr->p_type = PT_NOTE;
1227                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1228                 phdr->p_offset = phdr->p_paddr = notes_addr;
1229                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1230                 (ehdr->e_phnum)++;
1231                 phdr++;
1232         }
1233
1234         /* Prepare one PT_NOTE header for vmcoreinfo */
1235         phdr->p_type = PT_NOTE;
1236         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1237         phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1238         (ehdr->e_phnum)++;
1239         phdr++;
1240
1241         /* Prepare PT_LOAD type program header for kernel text region */
1242         if (kernel_map) {
1243                 phdr->p_type = PT_LOAD;
1244                 phdr->p_flags = PF_R|PF_W|PF_X;
1245                 phdr->p_vaddr = (Elf64_Addr)_text;
1246                 phdr->p_filesz = phdr->p_memsz = _end - _text;
1247                 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1248                 ehdr->e_phnum++;
1249                 phdr++;
1250         }
1251
1252         /* Go through all the ranges in mem->ranges[] and prepare phdr */
1253         for (i = 0; i < mem->nr_ranges; i++) {
1254                 mstart = mem->ranges[i].start;
1255                 mend = mem->ranges[i].end;
1256
1257                 phdr->p_type = PT_LOAD;
1258                 phdr->p_flags = PF_R|PF_W|PF_X;
1259                 phdr->p_offset  = mstart;
1260
1261                 phdr->p_paddr = mstart;
1262                 phdr->p_vaddr = (unsigned long long) __va(mstart);
1263                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1264                 phdr->p_align = 0;
1265                 ehdr->e_phnum++;
1266                 phdr++;
1267                 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",
1268                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1269                         ehdr->e_phnum, phdr->p_offset);
1270         }
1271
1272         *addr = buf;
1273         *sz = elf_sz;
1274         return 0;
1275 }