kernel/kexec_file.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * kexec: kexec_file_load system call
   4  *
   5  * Copyright (C) 2014 Red Hat Inc.
   6  * Authors:
   7  *      Vivek Goyal <vgoyal@redhat.com>
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/capability.h>
  13 #include <linux/mm.h>
  14 #include <linux/file.h>
  15 #include <linux/slab.h>
  16 #include <linux/kexec.h>
  17 #include <linux/memblock.h>
  18 #include <linux/mutex.h>
  19 #include <linux/list.h>
  20 #include <linux/fs.h>
  21 #include <linux/ima.h>
  22 #include <crypto/hash.h>
  23 #include <crypto/sha.h>
  24 #include <linux/elf.h>
  25 #include <linux/elfcore.h>
  26 #include <linux/kernel.h>
  27 #include <linux/syscalls.h>
  28 #include <linux/vmalloc.h>
  29 #include "kexec_internal.h"
  30
  31 static int kexec_calculate_store_digests(struct kimage *image);
  32
  33 /*
  34  * Currently this is the only default function that is exported as some
  35  * architectures need it to do additional handlings.
  36  * In the future, other default functions may be exported too if required.
  37  */
  38 int kexec_image_probe_default(struct kimage *image, void *buf,
  39                               unsigned long buf_len)
  40 {
  41         const struct kexec_file_ops * const *fops;
  42         int ret = -ENOEXEC;
  43
  44         for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
  45                 ret = (*fops)->probe(buf, buf_len);
  46                 if (!ret) {
  47                         image->fops = *fops;
  48                         return ret;
  49                 }
  50         }
  51
  52         return ret;
  53 }
  54
  55 /* Architectures can provide this probe function */
  56 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
  57                                          unsigned long buf_len)
  58 {
  59         return kexec_image_probe_default(image, buf, buf_len);
  60 }
  61
  62 static void *kexec_image_load_default(struct kimage *image)
  63 {
  64         if (!image->fops || !image->fops->load)
  65                 return ERR_PTR(-ENOEXEC);
  66
  67         return image->fops->load(image, image->kernel_buf,
  68                                  image->kernel_buf_len, image->initrd_buf,
  69                                  image->initrd_buf_len, image->cmdline_buf,
  70                                  image->cmdline_buf_len);
  71 }
  72
  73 void * __weak arch_kexec_kernel_image_load(struct kimage *image)
  74 {
  75         return kexec_image_load_default(image);
  76 }
  77
  78 int kexec_image_post_load_cleanup_default(struct kimage *image)
  79 {
  80         if (!image->fops || !image->fops->cleanup)
  81                 return 0;
  82
  83         return image->fops->cleanup(image->image_loader_data);
  84 }
  85
  86 int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
  87 {
  88         return kexec_image_post_load_cleanup_default(image);
  89 }
  90
  91 #ifdef CONFIG_KEXEC_VERIFY_SIG
  92 static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
  93                                           unsigned long buf_len)
  94 {
  95         if (!image->fops || !image->fops->verify_sig) {
  96                 pr_debug("kernel loader does not support signature verification.\n");
  97                 return -EKEYREJECTED;
  98         }
  99
 100         return image->fops->verify_sig(buf, buf_len);
 101 }
 102
 103 int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
 104                                         unsigned long buf_len)
 105 {
 106         return kexec_image_verify_sig_default(image, buf, buf_len);
 107 }
 108 #endif
 109
 110 /*
 111  * arch_kexec_apply_relocations_add - apply relocations of type RELA
 112  * @pi:         Purgatory to be relocated.
 113  * @section:    Section relocations applying to.
 114  * @relsec:     Section containing RELAs.
 115  * @symtab:     Corresponding symtab.
 116  *
 117  * Return: 0 on success, negative errno on error.
 118  */
 119 int __weak
 120 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
 121                                  const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 122 {
 123         pr_err("RELA relocation unsupported.\n");
 124         return -ENOEXEC;
 125 }
 126
 127 /*
 128  * arch_kexec_apply_relocations - apply relocations of type REL
 129  * @pi:         Purgatory to be relocated.
 130  * @section:    Section relocations applying to.
 131  * @relsec:     Section containing RELs.
 132  * @symtab:     Corresponding symtab.
 133  *
 134  * Return: 0 on success, negative errno on error.
 135  */
 136 int __weak
 137 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
 138                              const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 139 {
 140         pr_err("REL relocation unsupported.\n");
 141         return -ENOEXEC;
 142 }
 143
 144 /*
 145  * Free up memory used by kernel, initrd, and command line. This is temporary
 146  * memory allocation which is not needed any more after these buffers have
 147  * been loaded into separate segments and have been copied elsewhere.
 148  */
 149 void kimage_file_post_load_cleanup(struct kimage *image)
 150 {
 151         struct purgatory_info *pi = &image->purgatory_info;
 152
 153         vfree(image->kernel_buf);
 154         image->kernel_buf = NULL;
 155
 156         vfree(image->initrd_buf);
 157         image->initrd_buf = NULL;
 158
 159         kfree(image->cmdline_buf);
 160         image->cmdline_buf = NULL;
 161
 162         vfree(pi->purgatory_buf);
 163         pi->purgatory_buf = NULL;
 164
 165         vfree(pi->sechdrs);
 166         pi->sechdrs = NULL;
 167
 168         /* See if architecture has anything to cleanup post load */
 169         arch_kimage_file_post_load_cleanup(image);
 170
 171         /*
 172          * Above call should have called into bootloader to free up
 173          * any data stored in kimage->image_loader_data. It should
 174          * be ok now to free it up.
 175          */
 176         kfree(image->image_loader_data);
 177         image->image_loader_data = NULL;
 178 }
 179
 180 /*
 181  * In file mode list of segments is prepared by kernel. Copy relevant
 182  * data from user space, do error checking, prepare segment list
 183  */
 184 static int
 185 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 186                              const char __user *cmdline_ptr,
 187                              unsigned long cmdline_len, unsigned flags)
 188 {
 189         int ret = 0;
 190         void *ldata;
 191         loff_t size;
 192
 193         ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
 194                                        &size, INT_MAX, READING_KEXEC_IMAGE);
 195         if (ret)
 196                 return ret;
 197         image->kernel_buf_len = size;
 198
 199         /* IMA needs to pass the measurement list to the next kernel. */
 200         ima_add_kexec_buffer(image);
 201
 202         /* Call arch image probe handlers */
 203         ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
 204                                             image->kernel_buf_len);
 205         if (ret)
 206                 goto out;
 207
 208 #ifdef CONFIG_KEXEC_VERIFY_SIG
 209         ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
 210                                            image->kernel_buf_len);
 211         if (ret) {
 212                 pr_debug("kernel signature verification failed.\n");
 213                 goto out;
 214         }
 215         pr_debug("kernel signature verification successful.\n");
 216 #endif
 217         /* It is possible that there no initramfs is being loaded */
 218         if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
 219                 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
 220                                                &size, INT_MAX,
 221                                                READING_KEXEC_INITRAMFS);
 222                 if (ret)
 223                         goto out;
 224                 image->initrd_buf_len = size;
 225         }
 226
 227         if (cmdline_len) {
 228                 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
 229                 if (IS_ERR(image->cmdline_buf)) {
 230                         ret = PTR_ERR(image->cmdline_buf);
 231                         image->cmdline_buf = NULL;
 232                         goto out;
 233                 }
 234
 235                 image->cmdline_buf_len = cmdline_len;
 236
 237                 /* command line should be a string with last byte null */
 238                 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
 239                         ret = -EINVAL;
 240                         goto out;
 241                 }
 242         }
 243
 244         /* Call arch image load handlers */
 245         ldata = arch_kexec_kernel_image_load(image);
 246
 247         if (IS_ERR(ldata)) {
 248                 ret = PTR_ERR(ldata);
 249                 goto out;
 250         }
 251
 252         image->image_loader_data = ldata;
 253 out:
 254         /* In case of error, free up all allocated memory in this function */
 255         if (ret)
 256                 kimage_file_post_load_cleanup(image);
 257         return ret;
 258 }
 259
 260 static int
 261 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
 262                        int initrd_fd, const char __user *cmdline_ptr,
 263                        unsigned long cmdline_len, unsigned long flags)
 264 {
 265         int ret;
 266         struct kimage *image;
 267         bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
 268
 269         image = do_kimage_alloc_init();
 270         if (!image)
 271                 return -ENOMEM;
 272
 273         image->file_mode = 1;
 274
 275         if (kexec_on_panic) {
 276                 /* Enable special crash kernel control page alloc policy. */
 277                 image->control_page = crashk_res.start;
 278                 image->type = KEXEC_TYPE_CRASH;
 279         }
 280
 281         ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
 282                                            cmdline_ptr, cmdline_len, flags);
 283         if (ret)
 284                 goto out_free_image;
 285
 286         ret = sanity_check_segment_list(image);
 287         if (ret)
 288                 goto out_free_post_load_bufs;
 289
 290         ret = -ENOMEM;
 291         image->control_code_page = kimage_alloc_control_pages(image,
 292                                            get_order(KEXEC_CONTROL_PAGE_SIZE));
 293         if (!image->control_code_page) {
 294                 pr_err("Could not allocate control_code_buffer\n");
 295                 goto out_free_post_load_bufs;
 296         }
 297
 298         if (!kexec_on_panic) {
 299                 image->swap_page = kimage_alloc_control_pages(image, 0);
 300                 if (!image->swap_page) {
 301                         pr_err("Could not allocate swap buffer\n");
 302                         goto out_free_control_pages;
 303                 }
 304         }
 305
 306         *rimage = image;
 307         return 0;
 308 out_free_control_pages:
 309         kimage_free_page_list(&image->control_pages);
 310 out_free_post_load_bufs:
 311         kimage_file_post_load_cleanup(image);
 312 out_free_image:
 313         kfree(image);
 314         return ret;
 315 }
 316
 317 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 318                 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
 319                 unsigned long, flags)
 320 {
 321         int ret = 0, i;
 322         struct kimage **dest_image, *image;
 323
 324         /* We only trust the superuser with rebooting the system. */
 325         if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
 326                 return -EPERM;
 327
 328         /* Make sure we have a legal set of flags */
 329         if (flags != (flags & KEXEC_FILE_FLAGS))
 330                 return -EINVAL;
 331
 332         image = NULL;
 333
 334         if (!mutex_trylock(&kexec_mutex))
 335                 return -EBUSY;
 336
 337         dest_image = &kexec_image;
 338         if (flags & KEXEC_FILE_ON_CRASH) {
 339                 dest_image = &kexec_crash_image;
 340                 if (kexec_crash_image)
 341                         arch_kexec_unprotect_crashkres();
 342         }
 343
 344         if (flags & KEXEC_FILE_UNLOAD)
 345                 goto exchange;
 346
 347         /*
 348          * In case of crash, new kernel gets loaded in reserved region. It is
 349          * same memory where old crash kernel might be loaded. Free any
 350          * current crash dump kernel before we corrupt it.
 351          */
 352         if (flags & KEXEC_FILE_ON_CRASH)
 353                 kimage_free(xchg(&kexec_crash_image, NULL));
 354
 355         ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
 356                                      cmdline_len, flags);
 357         if (ret)
 358                 goto out;
 359
 360         ret = machine_kexec_prepare(image);
 361         if (ret)
 362                 goto out;
 363
 364         /*
 365          * Some architecture(like S390) may touch the crash memory before
 366          * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
 367          */
 368         ret = kimage_crash_copy_vmcoreinfo(image);
 369         if (ret)
 370                 goto out;
 371
 372         ret = kexec_calculate_store_digests(image);
 373         if (ret)
 374                 goto out;
 375
 376         for (i = 0; i < image->nr_segments; i++) {
 377                 struct kexec_segment *ksegment;
 378
 379                 ksegment = &image->segment[i];
 380                 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
 381                          i, ksegment->buf, ksegment->bufsz, ksegment->mem,
 382                          ksegment->memsz);
 383
 384                 ret = kimage_load_segment(image, &image->segment[i]);
 385                 if (ret)
 386                         goto out;
 387         }
 388
 389         kimage_terminate(image);
 390
 391         /*
 392          * Free up any temporary buffers allocated which are not needed
 393          * after image has been loaded
 394          */
 395         kimage_file_post_load_cleanup(image);
 396 exchange:
 397         image = xchg(dest_image, image);
 398 out:
 399         if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
 400                 arch_kexec_protect_crashkres();
 401
 402         mutex_unlock(&kexec_mutex);
 403         kimage_free(image);
 404         return ret;
 405 }
 406
 407 static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
 408                                     struct kexec_buf *kbuf)
 409 {
 410         struct kimage *image = kbuf->image;
 411         unsigned long temp_start, temp_end;
 412
 413         temp_end = min(end, kbuf->buf_max);
 414         temp_start = temp_end - kbuf->memsz;
 415
 416         do {
 417                 /* align down start */
 418                 temp_start = temp_start & (~(kbuf->buf_align - 1));
 419
 420                 if (temp_start < start || temp_start < kbuf->buf_min)
 421                         return 0;
 422
 423                 temp_end = temp_start + kbuf->memsz - 1;
 424
 425                 /*
 426                  * Make sure this does not conflict with any of existing
 427                  * segments
 428                  */
 429                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
 430                         temp_start = temp_start - PAGE_SIZE;
 431                         continue;
 432                 }
 433
 434                 /* We found a suitable memory range */
 435                 break;
 436         } while (1);
 437
 438         /* If we are here, we found a suitable memory range */
 439         kbuf->mem = temp_start;
 440
 441         /* Success, stop navigating through remaining System RAM ranges */
 442         return 1;
 443 }
 444
 445 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
 446                                      struct kexec_buf *kbuf)
 447 {
 448         struct kimage *image = kbuf->image;
 449         unsigned long temp_start, temp_end;
 450
 451         temp_start = max(start, kbuf->buf_min);
 452
 453         do {
 454                 temp_start = ALIGN(temp_start, kbuf->buf_align);
 455                 temp_end = temp_start + kbuf->memsz - 1;
 456
 457                 if (temp_end > end || temp_end > kbuf->buf_max)
 458                         return 0;
 459                 /*
 460                  * Make sure this does not conflict with any of existing
 461                  * segments
 462                  */
 463                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
 464                         temp_start = temp_start + PAGE_SIZE;
 465                         continue;
 466                 }
 467
 468                 /* We found a suitable memory range */
 469                 break;
 470         } while (1);
 471
 472         /* If we are here, we found a suitable memory range */
 473         kbuf->mem = temp_start;
 474
 475         /* Success, stop navigating through remaining System RAM ranges */
 476         return 1;
 477 }
 478
 479 static int locate_mem_hole_callback(struct resource *res, void *arg)
 480 {
 481         struct kexec_buf *kbuf = (struct kexec_buf *)arg;
 482         u64 start = res->start, end = res->end;
 483         unsigned long sz = end - start + 1;
 484
 485         /* Returning 0 will take to next memory range */
 486         if (sz < kbuf->memsz)
 487                 return 0;
 488
 489         if (end < kbuf->buf_min || start > kbuf->buf_max)
 490                 return 0;
 491
 492         /*
 493          * Allocate memory top down with-in ram range. Otherwise bottom up
 494          * allocation.
 495          */
 496         if (kbuf->top_down)
 497                 return locate_mem_hole_top_down(start, end, kbuf);
 498         return locate_mem_hole_bottom_up(start, end, kbuf);
 499 }
 500
 501 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 502 static int kexec_walk_memblock(struct kexec_buf *kbuf,
 503                                int (*func)(struct resource *, void *))
 504 {
 505         int ret = 0;
 506         u64 i;
 507         phys_addr_t mstart, mend;
 508         struct resource res = { };
 509
 510         if (kbuf->image->type == KEXEC_TYPE_CRASH)
 511                 return func(&crashk_res, kbuf);
 512
 513         if (kbuf->top_down) {
 514                 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 515                                                 &mstart, &mend, NULL) {
 516                         /*
 517                          * In memblock, end points to the first byte after the
 518                          * range while in kexec, end points to the last byte
 519                          * in the range.
 520                          */
 521                         res.start = mstart;
 522                         res.end = mend - 1;
 523                         ret = func(&res, kbuf);
 524                         if (ret)
 525                                 break;
 526                 }
 527         } else {
 528                 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 529                                         &mstart, &mend, NULL) {
 530                         /*
 531                          * In memblock, end points to the first byte after the
 532                          * range while in kexec, end points to the last byte
 533                          * in the range.
 534                          */
 535                         res.start = mstart;
 536                         res.end = mend - 1;
 537                         ret = func(&res, kbuf);
 538                         if (ret)
 539                                 break;
 540                 }
 541         }
 542
 543         return ret;
 544 }
 545 #else
 546 static int kexec_walk_memblock(struct kexec_buf *kbuf,
 547                                int (*func)(struct resource *, void *))
 548 {
 549         return 0;
 550 }
 551 #endif
 552
 553 /**
 554  * kexec_walk_resources - call func(data) on free memory regions
 555  * @kbuf:       Context info for the search. Also passed to @func.
 556  * @func:       Function to call for each memory region.
 557  *
 558  * Return: The memory walk will stop when func returns a non-zero value
 559  * and that value will be returned. If all free regions are visited without
 560  * func returning non-zero, then zero will be returned.
 561  */
 562 static int kexec_walk_resources(struct kexec_buf *kbuf,
 563                                 int (*func)(struct resource *, void *))
 564 {
 565         if (kbuf->image->type == KEXEC_TYPE_CRASH)
 566                 return walk_iomem_res_desc(crashk_res.desc,
 567                                            IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
 568                                            crashk_res.start, crashk_res.end,
 569                                            kbuf, func);
 570         else
 571                 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
 572 }
 573
 574 /**
 575  * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
 576  * @kbuf:       Parameters for the memory search.
 577  *
 578  * On success, kbuf->mem will have the start address of the memory region found.
 579  *
 580  * Return: 0 on success, negative errno on error.
 581  */
 582 int kexec_locate_mem_hole(struct kexec_buf *kbuf)
 583 {
 584         int ret;
 585
 586         /* Arch knows where to place */
 587         if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
 588                 return 0;
 589
 590         if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
 591                 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
 592         else
 593                 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
 594
 595         return ret == 1 ? 0 : -EADDRNOTAVAIL;
 596 }
 597
 598 /**
 599  * kexec_add_buffer - place a buffer in a kexec segment
 600  * @kbuf:       Buffer contents and memory parameters.
 601  *
 602  * This function assumes that kexec_mutex is held.
 603  * On successful return, @kbuf->mem will have the physical address of
 604  * the buffer in memory.
 605  *
 606  * Return: 0 on success, negative errno on error.
 607  */
 608 int kexec_add_buffer(struct kexec_buf *kbuf)
 609 {
 610
 611         struct kexec_segment *ksegment;
 612         int ret;
 613
 614         /* Currently adding segment this way is allowed only in file mode */
 615         if (!kbuf->image->file_mode)
 616                 return -EINVAL;
 617
 618         if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
 619                 return -EINVAL;
 620
 621         /*
 622          * Make sure we are not trying to add buffer after allocating
 623          * control pages. All segments need to be placed first before
 624          * any control pages are allocated. As control page allocation
 625          * logic goes through list of segments to make sure there are
 626          * no destination overlaps.
 627          */
 628         if (!list_empty(&kbuf->image->control_pages)) {
 629                 WARN_ON(1);
 630                 return -EINVAL;
 631         }
 632
 633         /* Ensure minimum alignment needed for segments. */
 634         kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
 635         kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
 636
 637         /* Walk the RAM ranges and allocate a suitable range for the buffer */
 638         ret = kexec_locate_mem_hole(kbuf);
 639         if (ret)
 640                 return ret;
 641
 642         /* Found a suitable memory range */
 643         ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
 644         ksegment->kbuf = kbuf->buffer;
 645         ksegment->bufsz = kbuf->bufsz;
 646         ksegment->mem = kbuf->mem;
 647         ksegment->memsz = kbuf->memsz;
 648         kbuf->image->nr_segments++;
 649         return 0;
 650 }
 651
 652 /* Calculate and store the digest of segments */
 653 static int kexec_calculate_store_digests(struct kimage *image)
 654 {
 655         struct crypto_shash *tfm;
 656         struct shash_desc *desc;
 657         int ret = 0, i, j, zero_buf_sz, sha_region_sz;
 658         size_t desc_size, nullsz;
 659         char *digest;
 660         void *zero_buf;
 661         struct kexec_sha_region *sha_regions;
 662         struct purgatory_info *pi = &image->purgatory_info;
 663
 664         if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
 665                 return 0;
 666
 667         zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
 668         zero_buf_sz = PAGE_SIZE;
 669
 670         tfm = crypto_alloc_shash("sha256", 0, 0);
 671         if (IS_ERR(tfm)) {
 672                 ret = PTR_ERR(tfm);
 673                 goto out;
 674         }
 675
 676         desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
 677         desc = kzalloc(desc_size, GFP_KERNEL);
 678         if (!desc) {
 679                 ret = -ENOMEM;
 680                 goto out_free_tfm;
 681         }
 682
 683         sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
 684         sha_regions = vzalloc(sha_region_sz);
 685         if (!sha_regions)
 686                 goto out_free_desc;
 687
 688         desc->tfm   = tfm;
 689
 690         ret = crypto_shash_init(desc);
 691         if (ret < 0)
 692                 goto out_free_sha_regions;
 693
 694         digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
 695         if (!digest) {
 696                 ret = -ENOMEM;
 697                 goto out_free_sha_regions;
 698         }
 699
 700         for (j = i = 0; i < image->nr_segments; i++) {
 701                 struct kexec_segment *ksegment;
 702
 703                 ksegment = &image->segment[i];
 704                 /*
 705                  * Skip purgatory as it will be modified once we put digest
 706                  * info in purgatory.
 707                  */
 708                 if (ksegment->kbuf == pi->purgatory_buf)
 709                         continue;
 710
 711                 ret = crypto_shash_update(desc, ksegment->kbuf,
 712                                           ksegment->bufsz);
 713                 if (ret)
 714                         break;
 715
 716                 /*
 717                  * Assume rest of the buffer is filled with zero and
 718                  * update digest accordingly.
 719                  */
 720                 nullsz = ksegment->memsz - ksegment->bufsz;
 721                 while (nullsz) {
 722                         unsigned long bytes = nullsz;
 723
 724                         if (bytes > zero_buf_sz)
 725                                 bytes = zero_buf_sz;
 726                         ret = crypto_shash_update(desc, zero_buf, bytes);
 727                         if (ret)
 728                                 break;
 729                         nullsz -= bytes;
 730                 }
 731
 732                 if (ret)
 733                         break;
 734
 735                 sha_regions[j].start = ksegment->mem;
 736                 sha_regions[j].len = ksegment->memsz;
 737                 j++;
 738         }
 739
 740         if (!ret) {
 741                 ret = crypto_shash_final(desc, digest);
 742                 if (ret)
 743                         goto out_free_digest;
 744                 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
 745                                                      sha_regions, sha_region_sz, 0);
 746                 if (ret)
 747                         goto out_free_digest;
 748
 749                 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
 750                                                      digest, SHA256_DIGEST_SIZE, 0);
 751                 if (ret)
 752                         goto out_free_digest;
 753         }
 754
 755 out_free_digest:
 756         kfree(digest);
 757 out_free_sha_regions:
 758         vfree(sha_regions);
 759 out_free_desc:
 760         kfree(desc);
 761 out_free_tfm:
 762         kfree(tfm);
 763 out:
 764         return ret;
 765 }
 766
 767 #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
 768 /*
 769  * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
 770  * @pi:         Purgatory to be loaded.
 771  * @kbuf:       Buffer to setup.
 772  *
 773  * Allocates the memory needed for the buffer. Caller is responsible to free
 774  * the memory after use.
 775  *
 776  * Return: 0 on success, negative errno on error.
 777  */
 778 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
 779                                       struct kexec_buf *kbuf)
 780 {
 781         const Elf_Shdr *sechdrs;
 782         unsigned long bss_align;
 783         unsigned long bss_sz;
 784         unsigned long align;
 785         int i, ret;
 786
 787         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 788         kbuf->buf_align = bss_align = 1;
 789         kbuf->bufsz = bss_sz = 0;
 790
 791         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 792                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 793                         continue;
 794
 795                 align = sechdrs[i].sh_addralign;
 796                 if (sechdrs[i].sh_type != SHT_NOBITS) {
 797                         if (kbuf->buf_align < align)
 798                                 kbuf->buf_align = align;
 799                         kbuf->bufsz = ALIGN(kbuf->bufsz, align);
 800                         kbuf->bufsz += sechdrs[i].sh_size;
 801                 } else {
 802                         if (bss_align < align)
 803                                 bss_align = align;
 804                         bss_sz = ALIGN(bss_sz, align);
 805                         bss_sz += sechdrs[i].sh_size;
 806                 }
 807         }
 808         kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
 809         kbuf->memsz = kbuf->bufsz + bss_sz;
 810         if (kbuf->buf_align < bss_align)
 811                 kbuf->buf_align = bss_align;
 812
 813         kbuf->buffer = vzalloc(kbuf->bufsz);
 814         if (!kbuf->buffer)
 815                 return -ENOMEM;
 816         pi->purgatory_buf = kbuf->buffer;
 817
 818         ret = kexec_add_buffer(kbuf);
 819         if (ret)
 820                 goto out;
 821
 822         return 0;
 823 out:
 824         vfree(pi->purgatory_buf);
 825         pi->purgatory_buf = NULL;
 826         return ret;
 827 }
 828
 829 /*
 830  * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
 831  * @pi:         Purgatory to be loaded.
 832  * @kbuf:       Buffer prepared to store purgatory.
 833  *
 834  * Allocates the memory needed for the buffer. Caller is responsible to free
 835  * the memory after use.
 836  *
 837  * Return: 0 on success, negative errno on error.
 838  */
 839 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 840                                          struct kexec_buf *kbuf)
 841 {
 842         unsigned long bss_addr;
 843         unsigned long offset;
 844         Elf_Shdr *sechdrs;
 845         int i;
 846
 847         /*
 848          * The section headers in kexec_purgatory are read-only. In order to
 849          * have them modifiable make a temporary copy.
 850          */
 851         sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
 852         if (!sechdrs)
 853                 return -ENOMEM;
 854         memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
 855                pi->ehdr->e_shnum * sizeof(Elf_Shdr));
 856         pi->sechdrs = sechdrs;
 857
 858         offset = 0;
 859         bss_addr = kbuf->mem + kbuf->bufsz;
 860         kbuf->image->start = pi->ehdr->e_entry;
 861
 862         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 863                 unsigned long align;
 864                 void *src, *dst;
 865
 866                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 867                         continue;
 868
 869                 align = sechdrs[i].sh_addralign;
 870                 if (sechdrs[i].sh_type == SHT_NOBITS) {
 871                         bss_addr = ALIGN(bss_addr, align);
 872                         sechdrs[i].sh_addr = bss_addr;
 873                         bss_addr += sechdrs[i].sh_size;
 874                         continue;
 875                 }
 876
 877                 offset = ALIGN(offset, align);
 878                 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
 879                     pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
 880                     pi->ehdr->e_entry < (sechdrs[i].sh_addr
 881                                          + sechdrs[i].sh_size)) {
 882                         kbuf->image->start -= sechdrs[i].sh_addr;
 883                         kbuf->image->start += kbuf->mem + offset;
 884                 }
 885
 886                 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
 887                 dst = pi->purgatory_buf + offset;
 888                 memcpy(dst, src, sechdrs[i].sh_size);
 889
 890                 sechdrs[i].sh_addr = kbuf->mem + offset;
 891                 sechdrs[i].sh_offset = offset;
 892                 offset += sechdrs[i].sh_size;
 893         }
 894
 895         return 0;
 896 }
 897
 898 static int kexec_apply_relocations(struct kimage *image)
 899 {
 900         int i, ret;
 901         struct purgatory_info *pi = &image->purgatory_info;
 902         const Elf_Shdr *sechdrs;
 903
 904         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 905
 906         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 907                 const Elf_Shdr *relsec;
 908                 const Elf_Shdr *symtab;
 909                 Elf_Shdr *section;
 910
 911                 relsec = sechdrs + i;
 912
 913                 if (relsec->sh_type != SHT_RELA &&
 914                     relsec->sh_type != SHT_REL)
 915                         continue;
 916
 917                 /*
 918                  * For section of type SHT_RELA/SHT_REL,
 919                  * ->sh_link contains section header index of associated
 920                  * symbol table. And ->sh_info contains section header
 921                  * index of section to which relocations apply.
 922                  */
 923                 if (relsec->sh_info >= pi->ehdr->e_shnum ||
 924                     relsec->sh_link >= pi->ehdr->e_shnum)
 925                         return -ENOEXEC;
 926
 927                 section = pi->sechdrs + relsec->sh_info;
 928                 symtab = sechdrs + relsec->sh_link;
 929
 930                 if (!(section->sh_flags & SHF_ALLOC))
 931                         continue;
 932
 933                 /*
 934                  * symtab->sh_link contain section header index of associated
 935                  * string table.
 936                  */
 937                 if (symtab->sh_link >= pi->ehdr->e_shnum)
 938                         /* Invalid section number? */
 939                         continue;
 940
 941                 /*
 942                  * Respective architecture needs to provide support for applying
 943                  * relocations of type SHT_RELA/SHT_REL.
 944                  */
 945                 if (relsec->sh_type == SHT_RELA)
 946                         ret = arch_kexec_apply_relocations_add(pi, section,
 947                                                                relsec, symtab);
 948                 else if (relsec->sh_type == SHT_REL)
 949                         ret = arch_kexec_apply_relocations(pi, section,
 950                                                            relsec, symtab);
 951                 if (ret)
 952                         return ret;
 953         }
 954
 955         return 0;
 956 }
 957
 958 /*
 959  * kexec_load_purgatory - Load and relocate the purgatory object.
 960  * @image:      Image to add the purgatory to.
 961  * @kbuf:       Memory parameters to use.
 962  *
 963  * Allocates the memory needed for image->purgatory_info.sechdrs and
 964  * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
 965  * to free the memory after use.
 966  *
 967  * Return: 0 on success, negative errno on error.
 968  */
 969 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
 970 {
 971         struct purgatory_info *pi = &image->purgatory_info;
 972         int ret;
 973
 974         if (kexec_purgatory_size <= 0)
 975                 return -EINVAL;
 976
 977         pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
 978
 979         ret = kexec_purgatory_setup_kbuf(pi, kbuf);
 980         if (ret)
 981                 return ret;
 982
 983         ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
 984         if (ret)
 985                 goto out_free_kbuf;
 986
 987         ret = kexec_apply_relocations(image);
 988         if (ret)
 989                 goto out;
 990
 991         return 0;
 992 out:
 993         vfree(pi->sechdrs);
 994         pi->sechdrs = NULL;
 995 out_free_kbuf:
 996         vfree(pi->purgatory_buf);
 997         pi->purgatory_buf = NULL;
 998         return ret;
 999 }
1000
1001 /*
1002  * kexec_purgatory_find_symbol - find a symbol in the purgatory
1003  * @pi:         Purgatory to search in.
1004  * @name:       Name of the symbol.
1005  *
1006  * Return: pointer to symbol in read-only symtab on success, NULL on error.
1007  */
1008 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1009                                                   const char *name)
1010 {
1011         const Elf_Shdr *sechdrs;
1012         const Elf_Ehdr *ehdr;
1013         const Elf_Sym *syms;
1014         const char *strtab;
1015         int i, k;
1016
1017         if (!pi->ehdr)
1018                 return NULL;
1019
1020         ehdr = pi->ehdr;
1021         sechdrs = (void *)ehdr + ehdr->e_shoff;
1022
1023         for (i = 0; i < ehdr->e_shnum; i++) {
1024                 if (sechdrs[i].sh_type != SHT_SYMTAB)
1025                         continue;
1026
1027                 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1028                         /* Invalid strtab section number */
1029                         continue;
1030                 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1031                 syms = (void *)ehdr + sechdrs[i].sh_offset;
1032
1033                 /* Go through symbols for a match */
1034                 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1035                         if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1036                                 continue;
1037
1038                         if (strcmp(strtab + syms[k].st_name, name) != 0)
1039                                 continue;
1040
1041                         if (syms[k].st_shndx == SHN_UNDEF ||
1042                             syms[k].st_shndx >= ehdr->e_shnum) {
1043                                 pr_debug("Symbol: %s has bad section index %d.\n",
1044                                                 name, syms[k].st_shndx);
1045                                 return NULL;
1046                         }
1047
1048                         /* Found the symbol we are looking for */
1049                         return &syms[k];
1050                 }
1051         }
1052
1053         return NULL;
1054 }
1055
1056 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1057 {
1058         struct purgatory_info *pi = &image->purgatory_info;
1059         const Elf_Sym *sym;
1060         Elf_Shdr *sechdr;
1061
1062         sym = kexec_purgatory_find_symbol(pi, name);
1063         if (!sym)
1064                 return ERR_PTR(-EINVAL);
1065
1066         sechdr = &pi->sechdrs[sym->st_shndx];
1067
1068         /*
1069          * Returns the address where symbol will finally be loaded after
1070          * kexec_load_segment()
1071          */
1072         return (void *)(sechdr->sh_addr + sym->st_value);
1073 }
1074
1075 /*
1076  * Get or set value of a symbol. If "get_value" is true, symbol value is
1077  * returned in buf otherwise symbol value is set based on value in buf.
1078  */
1079 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1080                                    void *buf, unsigned int size, bool get_value)
1081 {
1082         struct purgatory_info *pi = &image->purgatory_info;
1083         const Elf_Sym *sym;
1084         Elf_Shdr *sec;
1085         char *sym_buf;
1086
1087         sym = kexec_purgatory_find_symbol(pi, name);
1088         if (!sym)
1089                 return -EINVAL;
1090
1091         if (sym->st_size != size) {
1092                 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1093                        name, (unsigned long)sym->st_size, size);
1094                 return -EINVAL;
1095         }
1096
1097         sec = pi->sechdrs + sym->st_shndx;
1098
1099         if (sec->sh_type == SHT_NOBITS) {
1100                 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1101                        get_value ? "get" : "set");
1102                 return -EINVAL;
1103         }
1104
1105         sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1106
1107         if (get_value)
1108                 memcpy((void *)buf, sym_buf, size);
1109         else
1110                 memcpy((void *)sym_buf, buf, size);
1111
1112         return 0;
1113 }
1114 #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1115
1116 int crash_exclude_mem_range(struct crash_mem *mem,
1117                             unsigned long long mstart, unsigned long long mend)
1118 {
1119         int i, j;
1120         unsigned long long start, end;
1121         struct crash_mem_range temp_range = {0, 0};
1122
1123         for (i = 0; i < mem->nr_ranges; i++) {
1124                 start = mem->ranges[i].start;
1125                 end = mem->ranges[i].end;
1126
1127                 if (mstart > end || mend < start)
1128                         continue;
1129
1130                 /* Truncate any area outside of range */
1131                 if (mstart < start)
1132                         mstart = start;
1133                 if (mend > end)
1134                         mend = end;
1135
1136                 /* Found completely overlapping range */
1137                 if (mstart == start && mend == end) {
1138                         mem->ranges[i].start = 0;
1139                         mem->ranges[i].end = 0;
1140                         if (i < mem->nr_ranges - 1) {
1141                                 /* Shift rest of the ranges to left */
1142                                 for (j = i; j < mem->nr_ranges - 1; j++) {
1143                                         mem->ranges[j].start =
1144                                                 mem->ranges[j+1].start;
1145                                         mem->ranges[j].end =
1146                                                         mem->ranges[j+1].end;
1147                                 }
1148                         }
1149                         mem->nr_ranges--;
1150                         return 0;
1151                 }
1152
1153                 if (mstart > start && mend < end) {
1154                         /* Split original range */
1155                         mem->ranges[i].end = mstart - 1;
1156                         temp_range.start = mend + 1;
1157                         temp_range.end = end;
1158                 } else if (mstart != start)
1159                         mem->ranges[i].end = mstart - 1;
1160                 else
1161                         mem->ranges[i].start = mend + 1;
1162                 break;
1163         }
1164
1165         /* If a split happened, add the split to array */
1166         if (!temp_range.end)
1167                 return 0;
1168
1169         /* Split happened */
1170         if (i == mem->max_nr_ranges - 1)
1171                 return -ENOMEM;
1172
1173         /* Location where new range should go */
1174         j = i + 1;
1175         if (j < mem->nr_ranges) {
1176                 /* Move over all ranges one slot towards the end */
1177                 for (i = mem->nr_ranges - 1; i >= j; i--)
1178                         mem->ranges[i + 1] = mem->ranges[i];
1179         }
1180
1181         mem->ranges[j].start = temp_range.start;
1182         mem->ranges[j].end = temp_range.end;
1183         mem->nr_ranges++;
1184         return 0;
1185 }
1186
1187 int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1188                           void **addr, unsigned long *sz)
1189 {
1190         Elf64_Ehdr *ehdr;
1191         Elf64_Phdr *phdr;
1192         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1193         unsigned char *buf;
1194         unsigned int cpu, i;
1195         unsigned long long notes_addr;
1196         unsigned long mstart, mend;
1197
1198         /* extra phdr for vmcoreinfo elf note */
1199         nr_phdr = nr_cpus + 1;
1200         nr_phdr += mem->nr_ranges;
1201
1202         /*
1203          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1204          * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1205          * I think this is required by tools like gdb. So same physical
1206          * memory will be mapped in two elf headers. One will contain kernel
1207          * text virtual addresses and other will have __va(physical) addresses.
1208          */
1209
1210         nr_phdr++;
1211         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1212         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1213
1214         buf = vzalloc(elf_sz);
1215         if (!buf)
1216                 return -ENOMEM;
1217
1218         ehdr = (Elf64_Ehdr *)buf;
1219         phdr = (Elf64_Phdr *)(ehdr + 1);
1220         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1221         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1222         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1223         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1224         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1225         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1226         ehdr->e_type = ET_CORE;
1227         ehdr->e_machine = ELF_ARCH;
1228         ehdr->e_version = EV_CURRENT;
1229         ehdr->e_phoff = sizeof(Elf64_Ehdr);
1230         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1231         ehdr->e_phentsize = sizeof(Elf64_Phdr);
1232
1233         /* Prepare one phdr of type PT_NOTE for each present cpu */
1234         for_each_present_cpu(cpu) {
1235                 phdr->p_type = PT_NOTE;
1236                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1237                 phdr->p_offset = phdr->p_paddr = notes_addr;
1238                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1239                 (ehdr->e_phnum)++;
1240                 phdr++;
1241         }
1242
1243         /* Prepare one PT_NOTE header for vmcoreinfo */
1244         phdr->p_type = PT_NOTE;
1245         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1246         phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1247         (ehdr->e_phnum)++;
1248         phdr++;
1249
1250         /* Prepare PT_LOAD type program header for kernel text region */
1251         if (kernel_map) {
1252                 phdr->p_type = PT_LOAD;
1253                 phdr->p_flags = PF_R|PF_W|PF_X;
1254                 phdr->p_vaddr = (Elf64_Addr)_text;
1255                 phdr->p_filesz = phdr->p_memsz = _end - _text;
1256                 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1257                 ehdr->e_phnum++;
1258                 phdr++;
1259         }
1260
1261         /* Go through all the ranges in mem->ranges[] and prepare phdr */
1262         for (i = 0; i < mem->nr_ranges; i++) {
1263                 mstart = mem->ranges[i].start;
1264                 mend = mem->ranges[i].end;
1265
1266                 phdr->p_type = PT_LOAD;
1267                 phdr->p_flags = PF_R|PF_W|PF_X;
1268                 phdr->p_offset  = mstart;
1269
1270                 phdr->p_paddr = mstart;
1271                 phdr->p_vaddr = (unsigned long long) __va(mstart);
1272                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1273                 phdr->p_align = 0;
1274                 ehdr->e_phnum++;
1275                 phdr++;
1276                 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",
1277                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1278                         ehdr->e_phnum, phdr->p_offset);
1279         }
1280
1281         *addr = buf;
1282         *sz = elf_sz;
1283         return 0;
1284 }