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/memblock.h>
  20 #include <linux/mutex.h>
  21 #include <linux/list.h>
  22 #include <linux/fs.h>
  23 #include <linux/ima.h>
  24 #include <crypto/hash.h>
  25 #include <crypto/sha.h>
  26 #include <linux/elf.h>
  27 #include <linux/elfcore.h>
  28 #include <linux/kernel.h>
  29 #include <linux/syscalls.h>
  30 #include <linux/vmalloc.h>
  31 #include "kexec_internal.h"
  32
  33 static int kexec_calculate_store_digests(struct kimage *image);
  34
  35 /*
  36  * Currently this is the only default function that is exported as some
  37  * architectures need it to do additional handlings.
  38  * In the future, other default functions may be exported too if required.
  39  */
  40 int kexec_image_probe_default(struct kimage *image, void *buf,
  41                               unsigned long buf_len)
  42 {
  43         const struct kexec_file_ops * const *fops;
  44         int ret = -ENOEXEC;
  45
  46         for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
  47                 ret = (*fops)->probe(buf, buf_len);
  48                 if (!ret) {
  49                         image->fops = *fops;
  50                         return ret;
  51                 }
  52         }
  53
  54         return ret;
  55 }
  56
  57 /* Architectures can provide this probe function */
  58 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
  59                                          unsigned long buf_len)
  60 {
  61         return kexec_image_probe_default(image, buf, buf_len);
  62 }
  63
  64 static void *kexec_image_load_default(struct kimage *image)
  65 {
  66         if (!image->fops || !image->fops->load)
  67                 return ERR_PTR(-ENOEXEC);
  68
  69         return image->fops->load(image, image->kernel_buf,
  70                                  image->kernel_buf_len, image->initrd_buf,
  71                                  image->initrd_buf_len, image->cmdline_buf,
  72                                  image->cmdline_buf_len);
  73 }
  74
  75 void * __weak arch_kexec_kernel_image_load(struct kimage *image)
  76 {
  77         return kexec_image_load_default(image);
  78 }
  79
  80 int kexec_image_post_load_cleanup_default(struct kimage *image)
  81 {
  82         if (!image->fops || !image->fops->cleanup)
  83                 return 0;
  84
  85         return image->fops->cleanup(image->image_loader_data);
  86 }
  87
  88 int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
  89 {
  90         return kexec_image_post_load_cleanup_default(image);
  91 }
  92
  93 #ifdef CONFIG_KEXEC_VERIFY_SIG
  94 static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
  95                                           unsigned long buf_len)
  96 {
  97         if (!image->fops || !image->fops->verify_sig) {
  98                 pr_debug("kernel loader does not support signature verification.\n");
  99                 return -EKEYREJECTED;
 100         }
 101
 102         return image->fops->verify_sig(buf, buf_len);
 103 }
 104
 105 int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
 106                                         unsigned long buf_len)
 107 {
 108         return kexec_image_verify_sig_default(image, buf, buf_len);
 109 }
 110 #endif
 111
 112 /*
 113  * arch_kexec_apply_relocations_add - apply relocations of type RELA
 114  * @pi:         Purgatory to be relocated.
 115  * @section:    Section relocations applying to.
 116  * @relsec:     Section containing RELAs.
 117  * @symtab:     Corresponding symtab.
 118  *
 119  * Return: 0 on success, negative errno on error.
 120  */
 121 int __weak
 122 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
 123                                  const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 124 {
 125         pr_err("RELA relocation unsupported.\n");
 126         return -ENOEXEC;
 127 }
 128
 129 /*
 130  * arch_kexec_apply_relocations - apply relocations of type REL
 131  * @pi:         Purgatory to be relocated.
 132  * @section:    Section relocations applying to.
 133  * @relsec:     Section containing RELs.
 134  * @symtab:     Corresponding symtab.
 135  *
 136  * Return: 0 on success, negative errno on error.
 137  */
 138 int __weak
 139 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
 140                              const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 141 {
 142         pr_err("REL relocation unsupported.\n");
 143         return -ENOEXEC;
 144 }
 145
 146 /*
 147  * Free up memory used by kernel, initrd, and command line. This is temporary
 148  * memory allocation which is not needed any more after these buffers have
 149  * been loaded into separate segments and have been copied elsewhere.
 150  */
 151 void kimage_file_post_load_cleanup(struct kimage *image)
 152 {
 153         struct purgatory_info *pi = &image->purgatory_info;
 154
 155         vfree(image->kernel_buf);
 156         image->kernel_buf = NULL;
 157
 158         vfree(image->initrd_buf);
 159         image->initrd_buf = NULL;
 160
 161         kfree(image->cmdline_buf);
 162         image->cmdline_buf = NULL;
 163
 164         vfree(pi->purgatory_buf);
 165         pi->purgatory_buf = NULL;
 166
 167         vfree(pi->sechdrs);
 168         pi->sechdrs = NULL;
 169
 170         /* See if architecture has anything to cleanup post load */
 171         arch_kimage_file_post_load_cleanup(image);
 172
 173         /*
 174          * Above call should have called into bootloader to free up
 175          * any data stored in kimage->image_loader_data. It should
 176          * be ok now to free it up.
 177          */
 178         kfree(image->image_loader_data);
 179         image->image_loader_data = NULL;
 180 }
 181
 182 /*
 183  * In file mode list of segments is prepared by kernel. Copy relevant
 184  * data from user space, do error checking, prepare segment list
 185  */
 186 static int
 187 kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 188                              const char __user *cmdline_ptr,
 189                              unsigned long cmdline_len, unsigned flags)
 190 {
 191         int ret = 0;
 192         void *ldata;
 193         loff_t size;
 194
 195         ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
 196                                        &size, INT_MAX, READING_KEXEC_IMAGE);
 197         if (ret)
 198                 return ret;
 199         image->kernel_buf_len = size;
 200
 201         /* IMA needs to pass the measurement list to the next kernel. */
 202         ima_add_kexec_buffer(image);
 203
 204         /* Call arch image probe handlers */
 205         ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
 206                                             image->kernel_buf_len);
 207         if (ret)
 208                 goto out;
 209
 210 #ifdef CONFIG_KEXEC_VERIFY_SIG
 211         ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
 212                                            image->kernel_buf_len);
 213         if (ret) {
 214                 pr_debug("kernel signature verification failed.\n");
 215                 goto out;
 216         }
 217         pr_debug("kernel signature verification successful.\n");
 218 #endif
 219         /* It is possible that there no initramfs is being loaded */
 220         if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
 221                 ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
 222                                                &size, INT_MAX,
 223                                                READING_KEXEC_INITRAMFS);
 224                 if (ret)
 225                         goto out;
 226                 image->initrd_buf_len = size;
 227         }
 228
 229         if (cmdline_len) {
 230                 image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
 231                 if (IS_ERR(image->cmdline_buf)) {
 232                         ret = PTR_ERR(image->cmdline_buf);
 233                         image->cmdline_buf = NULL;
 234                         goto out;
 235                 }
 236
 237                 image->cmdline_buf_len = cmdline_len;
 238
 239                 /* command line should be a string with last byte null */
 240                 if (image->cmdline_buf[cmdline_len - 1] != '\0') {
 241                         ret = -EINVAL;
 242                         goto out;
 243                 }
 244         }
 245
 246         /* Call arch image load handlers */
 247         ldata = arch_kexec_kernel_image_load(image);
 248
 249         if (IS_ERR(ldata)) {
 250                 ret = PTR_ERR(ldata);
 251                 goto out;
 252         }
 253
 254         image->image_loader_data = ldata;
 255 out:
 256         /* In case of error, free up all allocated memory in this function */
 257         if (ret)
 258                 kimage_file_post_load_cleanup(image);
 259         return ret;
 260 }
 261
 262 static int
 263 kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
 264                        int initrd_fd, const char __user *cmdline_ptr,
 265                        unsigned long cmdline_len, unsigned long flags)
 266 {
 267         int ret;
 268         struct kimage *image;
 269         bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
 270
 271         image = do_kimage_alloc_init();
 272         if (!image)
 273                 return -ENOMEM;
 274
 275         image->file_mode = 1;
 276
 277         if (kexec_on_panic) {
 278                 /* Enable special crash kernel control page alloc policy. */
 279                 image->control_page = crashk_res.start;
 280                 image->type = KEXEC_TYPE_CRASH;
 281         }
 282
 283         ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
 284                                            cmdline_ptr, cmdline_len, flags);
 285         if (ret)
 286                 goto out_free_image;
 287
 288         ret = sanity_check_segment_list(image);
 289         if (ret)
 290                 goto out_free_post_load_bufs;
 291
 292         ret = -ENOMEM;
 293         image->control_code_page = kimage_alloc_control_pages(image,
 294                                            get_order(KEXEC_CONTROL_PAGE_SIZE));
 295         if (!image->control_code_page) {
 296                 pr_err("Could not allocate control_code_buffer\n");
 297                 goto out_free_post_load_bufs;
 298         }
 299
 300         if (!kexec_on_panic) {
 301                 image->swap_page = kimage_alloc_control_pages(image, 0);
 302                 if (!image->swap_page) {
 303                         pr_err("Could not allocate swap buffer\n");
 304                         goto out_free_control_pages;
 305                 }
 306         }
 307
 308         *rimage = image;
 309         return 0;
 310 out_free_control_pages:
 311         kimage_free_page_list(&image->control_pages);
 312 out_free_post_load_bufs:
 313         kimage_file_post_load_cleanup(image);
 314 out_free_image:
 315         kfree(image);
 316         return ret;
 317 }
 318
 319 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 320                 unsigned long, cmdline_len, const char __user *, cmdline_ptr,
 321                 unsigned long, flags)
 322 {
 323         int ret = 0, i;
 324         struct kimage **dest_image, *image;
 325
 326         /* We only trust the superuser with rebooting the system. */
 327         if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
 328                 return -EPERM;
 329
 330         /* Make sure we have a legal set of flags */
 331         if (flags != (flags & KEXEC_FILE_FLAGS))
 332                 return -EINVAL;
 333
 334         image = NULL;
 335
 336         if (!mutex_trylock(&kexec_mutex))
 337                 return -EBUSY;
 338
 339         dest_image = &kexec_image;
 340         if (flags & KEXEC_FILE_ON_CRASH) {
 341                 dest_image = &kexec_crash_image;
 342                 if (kexec_crash_image)
 343                         arch_kexec_unprotect_crashkres();
 344         }
 345
 346         if (flags & KEXEC_FILE_UNLOAD)
 347                 goto exchange;
 348
 349         /*
 350          * In case of crash, new kernel gets loaded in reserved region. It is
 351          * same memory where old crash kernel might be loaded. Free any
 352          * current crash dump kernel before we corrupt it.
 353          */
 354         if (flags & KEXEC_FILE_ON_CRASH)
 355                 kimage_free(xchg(&kexec_crash_image, NULL));
 356
 357         ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
 358                                      cmdline_len, flags);
 359         if (ret)
 360                 goto out;
 361
 362         ret = machine_kexec_prepare(image);
 363         if (ret)
 364                 goto out;
 365
 366         /*
 367          * Some architecture(like S390) may touch the crash memory before
 368          * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
 369          */
 370         ret = kimage_crash_copy_vmcoreinfo(image);
 371         if (ret)
 372                 goto out;
 373
 374         ret = kexec_calculate_store_digests(image);
 375         if (ret)
 376                 goto out;
 377
 378         for (i = 0; i < image->nr_segments; i++) {
 379                 struct kexec_segment *ksegment;
 380
 381                 ksegment = &image->segment[i];
 382                 pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
 383                          i, ksegment->buf, ksegment->bufsz, ksegment->mem,
 384                          ksegment->memsz);
 385
 386                 ret = kimage_load_segment(image, &image->segment[i]);
 387                 if (ret)
 388                         goto out;
 389         }
 390
 391         kimage_terminate(image);
 392
 393         /*
 394          * Free up any temporary buffers allocated which are not needed
 395          * after image has been loaded
 396          */
 397         kimage_file_post_load_cleanup(image);
 398 exchange:
 399         image = xchg(dest_image, image);
 400 out:
 401         if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
 402                 arch_kexec_protect_crashkres();
 403
 404         mutex_unlock(&kexec_mutex);
 405         kimage_free(image);
 406         return ret;
 407 }
 408
 409 static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
 410                                     struct kexec_buf *kbuf)
 411 {
 412         struct kimage *image = kbuf->image;
 413         unsigned long temp_start, temp_end;
 414
 415         temp_end = min(end, kbuf->buf_max);
 416         temp_start = temp_end - kbuf->memsz;
 417
 418         do {
 419                 /* align down start */
 420                 temp_start = temp_start & (~(kbuf->buf_align - 1));
 421
 422                 if (temp_start < start || temp_start < kbuf->buf_min)
 423                         return 0;
 424
 425                 temp_end = temp_start + kbuf->memsz - 1;
 426
 427                 /*
 428                  * Make sure this does not conflict with any of existing
 429                  * segments
 430                  */
 431                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
 432                         temp_start = temp_start - PAGE_SIZE;
 433                         continue;
 434                 }
 435
 436                 /* We found a suitable memory range */
 437                 break;
 438         } while (1);
 439
 440         /* If we are here, we found a suitable memory range */
 441         kbuf->mem = temp_start;
 442
 443         /* Success, stop navigating through remaining System RAM ranges */
 444         return 1;
 445 }
 446
 447 static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
 448                                      struct kexec_buf *kbuf)
 449 {
 450         struct kimage *image = kbuf->image;
 451         unsigned long temp_start, temp_end;
 452
 453         temp_start = max(start, kbuf->buf_min);
 454
 455         do {
 456                 temp_start = ALIGN(temp_start, kbuf->buf_align);
 457                 temp_end = temp_start + kbuf->memsz - 1;
 458
 459                 if (temp_end > end || temp_end > kbuf->buf_max)
 460                         return 0;
 461                 /*
 462                  * Make sure this does not conflict with any of existing
 463                  * segments
 464                  */
 465                 if (kimage_is_destination_range(image, temp_start, temp_end)) {
 466                         temp_start = temp_start + PAGE_SIZE;
 467                         continue;
 468                 }
 469
 470                 /* We found a suitable memory range */
 471                 break;
 472         } while (1);
 473
 474         /* If we are here, we found a suitable memory range */
 475         kbuf->mem = temp_start;
 476
 477         /* Success, stop navigating through remaining System RAM ranges */
 478         return 1;
 479 }
 480
 481 static int locate_mem_hole_callback(struct resource *res, void *arg)
 482 {
 483         struct kexec_buf *kbuf = (struct kexec_buf *)arg;
 484         u64 start = res->start, end = res->end;
 485         unsigned long sz = end - start + 1;
 486
 487         /* Returning 0 will take to next memory range */
 488         if (sz < kbuf->memsz)
 489                 return 0;
 490
 491         if (end < kbuf->buf_min || start > kbuf->buf_max)
 492                 return 0;
 493
 494         /*
 495          * Allocate memory top down with-in ram range. Otherwise bottom up
 496          * allocation.
 497          */
 498         if (kbuf->top_down)
 499                 return locate_mem_hole_top_down(start, end, kbuf);
 500         return locate_mem_hole_bottom_up(start, end, kbuf);
 501 }
 502
 503 #ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
 504 static int kexec_walk_memblock(struct kexec_buf *kbuf,
 505                                int (*func)(struct resource *, void *))
 506 {
 507         return 0;
 508 }
 509 #else
 510 static int kexec_walk_memblock(struct kexec_buf *kbuf,
 511                                int (*func)(struct resource *, void *))
 512 {
 513         int ret = 0;
 514         u64 i;
 515         phys_addr_t mstart, mend;
 516         struct resource res = { };
 517
 518         if (kbuf->image->type == KEXEC_TYPE_CRASH)
 519                 return func(&crashk_res, kbuf);
 520
 521         if (kbuf->top_down) {
 522                 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 523                                                 &mstart, &mend, NULL) {
 524                         /*
 525                          * In memblock, end points to the first byte after the
 526                          * range while in kexec, end points to the last byte
 527                          * in the range.
 528                          */
 529                         res.start = mstart;
 530                         res.end = mend - 1;
 531                         ret = func(&res, kbuf);
 532                         if (ret)
 533                                 break;
 534                 }
 535         } else {
 536                 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 537                                         &mstart, &mend, NULL) {
 538                         /*
 539                          * In memblock, end points to the first byte after the
 540                          * range while in kexec, end points to the last byte
 541                          * in the range.
 542                          */
 543                         res.start = mstart;
 544                         res.end = mend - 1;
 545                         ret = func(&res, kbuf);
 546                         if (ret)
 547                                 break;
 548                 }
 549         }
 550
 551         return ret;
 552 }
 553 #endif
 554
 555 /**
 556  * kexec_walk_resources - call func(data) on free memory regions
 557  * @kbuf:       Context info for the search. Also passed to @func.
 558  * @func:       Function to call for each memory region.
 559  *
 560  * Return: The memory walk will stop when func returns a non-zero value
 561  * and that value will be returned. If all free regions are visited without
 562  * func returning non-zero, then zero will be returned.
 563  */
 564 static int kexec_walk_resources(struct kexec_buf *kbuf,
 565                                 int (*func)(struct resource *, void *))
 566 {
 567         if (kbuf->image->type == KEXEC_TYPE_CRASH)
 568                 return walk_iomem_res_desc(crashk_res.desc,
 569                                            IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
 570                                            crashk_res.start, crashk_res.end,
 571                                            kbuf, func);
 572         else
 573                 return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
 574 }
 575
 576 /**
 577  * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
 578  * @kbuf:       Parameters for the memory search.
 579  *
 580  * On success, kbuf->mem will have the start address of the memory region found.
 581  *
 582  * Return: 0 on success, negative errno on error.
 583  */
 584 int kexec_locate_mem_hole(struct kexec_buf *kbuf)
 585 {
 586         int ret;
 587
 588         /* Arch knows where to place */
 589         if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
 590                 return 0;
 591
 592         if (IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
 593                 ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
 594         else
 595                 ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
 596
 597         return ret == 1 ? 0 : -EADDRNOTAVAIL;
 598 }
 599
 600 /**
 601  * kexec_add_buffer - place a buffer in a kexec segment
 602  * @kbuf:       Buffer contents and memory parameters.
 603  *
 604  * This function assumes that kexec_mutex is held.
 605  * On successful return, @kbuf->mem will have the physical address of
 606  * the buffer in memory.
 607  *
 608  * Return: 0 on success, negative errno on error.
 609  */
 610 int kexec_add_buffer(struct kexec_buf *kbuf)
 611 {
 612
 613         struct kexec_segment *ksegment;
 614         int ret;
 615
 616         /* Currently adding segment this way is allowed only in file mode */
 617         if (!kbuf->image->file_mode)
 618                 return -EINVAL;
 619
 620         if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
 621                 return -EINVAL;
 622
 623         /*
 624          * Make sure we are not trying to add buffer after allocating
 625          * control pages. All segments need to be placed first before
 626          * any control pages are allocated. As control page allocation
 627          * logic goes through list of segments to make sure there are
 628          * no destination overlaps.
 629          */
 630         if (!list_empty(&kbuf->image->control_pages)) {
 631                 WARN_ON(1);
 632                 return -EINVAL;
 633         }
 634
 635         /* Ensure minimum alignment needed for segments. */
 636         kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
 637         kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
 638
 639         /* Walk the RAM ranges and allocate a suitable range for the buffer */
 640         ret = kexec_locate_mem_hole(kbuf);
 641         if (ret)
 642                 return ret;
 643
 644         /* Found a suitable memory range */
 645         ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
 646         ksegment->kbuf = kbuf->buffer;
 647         ksegment->bufsz = kbuf->bufsz;
 648         ksegment->mem = kbuf->mem;
 649         ksegment->memsz = kbuf->memsz;
 650         kbuf->image->nr_segments++;
 651         return 0;
 652 }
 653
 654 /* Calculate and store the digest of segments */
 655 static int kexec_calculate_store_digests(struct kimage *image)
 656 {
 657         struct crypto_shash *tfm;
 658         struct shash_desc *desc;
 659         int ret = 0, i, j, zero_buf_sz, sha_region_sz;
 660         size_t desc_size, nullsz;
 661         char *digest;
 662         void *zero_buf;
 663         struct kexec_sha_region *sha_regions;
 664         struct purgatory_info *pi = &image->purgatory_info;
 665
 666         if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
 667                 return 0;
 668
 669         zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
 670         zero_buf_sz = PAGE_SIZE;
 671
 672         tfm = crypto_alloc_shash("sha256", 0, 0);
 673         if (IS_ERR(tfm)) {
 674                 ret = PTR_ERR(tfm);
 675                 goto out;
 676         }
 677
 678         desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
 679         desc = kzalloc(desc_size, GFP_KERNEL);
 680         if (!desc) {
 681                 ret = -ENOMEM;
 682                 goto out_free_tfm;
 683         }
 684
 685         sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
 686         sha_regions = vzalloc(sha_region_sz);
 687         if (!sha_regions)
 688                 goto out_free_desc;
 689
 690         desc->tfm   = tfm;
 691         desc->flags = 0;
 692
 693         ret = crypto_shash_init(desc);
 694         if (ret < 0)
 695                 goto out_free_sha_regions;
 696
 697         digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
 698         if (!digest) {
 699                 ret = -ENOMEM;
 700                 goto out_free_sha_regions;
 701         }
 702
 703         for (j = i = 0; i < image->nr_segments; i++) {
 704                 struct kexec_segment *ksegment;
 705
 706                 ksegment = &image->segment[i];
 707                 /*
 708                  * Skip purgatory as it will be modified once we put digest
 709                  * info in purgatory.
 710                  */
 711                 if (ksegment->kbuf == pi->purgatory_buf)
 712                         continue;
 713
 714                 ret = crypto_shash_update(desc, ksegment->kbuf,
 715                                           ksegment->bufsz);
 716                 if (ret)
 717                         break;
 718
 719                 /*
 720                  * Assume rest of the buffer is filled with zero and
 721                  * update digest accordingly.
 722                  */
 723                 nullsz = ksegment->memsz - ksegment->bufsz;
 724                 while (nullsz) {
 725                         unsigned long bytes = nullsz;
 726
 727                         if (bytes > zero_buf_sz)
 728                                 bytes = zero_buf_sz;
 729                         ret = crypto_shash_update(desc, zero_buf, bytes);
 730                         if (ret)
 731                                 break;
 732                         nullsz -= bytes;
 733                 }
 734
 735                 if (ret)
 736                         break;
 737
 738                 sha_regions[j].start = ksegment->mem;
 739                 sha_regions[j].len = ksegment->memsz;
 740                 j++;
 741         }
 742
 743         if (!ret) {
 744                 ret = crypto_shash_final(desc, digest);
 745                 if (ret)
 746                         goto out_free_digest;
 747                 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
 748                                                      sha_regions, sha_region_sz, 0);
 749                 if (ret)
 750                         goto out_free_digest;
 751
 752                 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
 753                                                      digest, SHA256_DIGEST_SIZE, 0);
 754                 if (ret)
 755                         goto out_free_digest;
 756         }
 757
 758 out_free_digest:
 759         kfree(digest);
 760 out_free_sha_regions:
 761         vfree(sha_regions);
 762 out_free_desc:
 763         kfree(desc);
 764 out_free_tfm:
 765         kfree(tfm);
 766 out:
 767         return ret;
 768 }
 769
 770 #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
 771 /*
 772  * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
 773  * @pi:         Purgatory to be loaded.
 774  * @kbuf:       Buffer to setup.
 775  *
 776  * Allocates the memory needed for the buffer. Caller is responsible to free
 777  * the memory after use.
 778  *
 779  * Return: 0 on success, negative errno on error.
 780  */
 781 static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
 782                                       struct kexec_buf *kbuf)
 783 {
 784         const Elf_Shdr *sechdrs;
 785         unsigned long bss_align;
 786         unsigned long bss_sz;
 787         unsigned long align;
 788         int i, ret;
 789
 790         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 791         kbuf->buf_align = bss_align = 1;
 792         kbuf->bufsz = bss_sz = 0;
 793
 794         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 795                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 796                         continue;
 797
 798                 align = sechdrs[i].sh_addralign;
 799                 if (sechdrs[i].sh_type != SHT_NOBITS) {
 800                         if (kbuf->buf_align < align)
 801                                 kbuf->buf_align = align;
 802                         kbuf->bufsz = ALIGN(kbuf->bufsz, align);
 803                         kbuf->bufsz += sechdrs[i].sh_size;
 804                 } else {
 805                         if (bss_align < align)
 806                                 bss_align = align;
 807                         bss_sz = ALIGN(bss_sz, align);
 808                         bss_sz += sechdrs[i].sh_size;
 809                 }
 810         }
 811         kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
 812         kbuf->memsz = kbuf->bufsz + bss_sz;
 813         if (kbuf->buf_align < bss_align)
 814                 kbuf->buf_align = bss_align;
 815
 816         kbuf->buffer = vzalloc(kbuf->bufsz);
 817         if (!kbuf->buffer)
 818                 return -ENOMEM;
 819         pi->purgatory_buf = kbuf->buffer;
 820
 821         ret = kexec_add_buffer(kbuf);
 822         if (ret)
 823                 goto out;
 824
 825         return 0;
 826 out:
 827         vfree(pi->purgatory_buf);
 828         pi->purgatory_buf = NULL;
 829         return ret;
 830 }
 831
 832 /*
 833  * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
 834  * @pi:         Purgatory to be loaded.
 835  * @kbuf:       Buffer prepared to store purgatory.
 836  *
 837  * Allocates the memory needed for the buffer. Caller is responsible to free
 838  * the memory after use.
 839  *
 840  * Return: 0 on success, negative errno on error.
 841  */
 842 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 843                                          struct kexec_buf *kbuf)
 844 {
 845         unsigned long bss_addr;
 846         unsigned long offset;
 847         Elf_Shdr *sechdrs;
 848         int i;
 849
 850         /*
 851          * The section headers in kexec_purgatory are read-only. In order to
 852          * have them modifiable make a temporary copy.
 853          */
 854         sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
 855         if (!sechdrs)
 856                 return -ENOMEM;
 857         memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
 858                pi->ehdr->e_shnum * sizeof(Elf_Shdr));
 859         pi->sechdrs = sechdrs;
 860
 861         offset = 0;
 862         bss_addr = kbuf->mem + kbuf->bufsz;
 863         kbuf->image->start = pi->ehdr->e_entry;
 864
 865         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 866                 unsigned long align;
 867                 void *src, *dst;
 868
 869                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 870                         continue;
 871
 872                 align = sechdrs[i].sh_addralign;
 873                 if (sechdrs[i].sh_type == SHT_NOBITS) {
 874                         bss_addr = ALIGN(bss_addr, align);
 875                         sechdrs[i].sh_addr = bss_addr;
 876                         bss_addr += sechdrs[i].sh_size;
 877                         continue;
 878                 }
 879
 880                 offset = ALIGN(offset, align);
 881                 if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
 882                     pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
 883                     pi->ehdr->e_entry < (sechdrs[i].sh_addr
 884                                          + sechdrs[i].sh_size)) {
 885                         kbuf->image->start -= sechdrs[i].sh_addr;
 886                         kbuf->image->start += kbuf->mem + offset;
 887                 }
 888
 889                 src = (void *)pi->ehdr + sechdrs[i].sh_offset;
 890                 dst = pi->purgatory_buf + offset;
 891                 memcpy(dst, src, sechdrs[i].sh_size);
 892
 893                 sechdrs[i].sh_addr = kbuf->mem + offset;
 894                 sechdrs[i].sh_offset = offset;
 895                 offset += sechdrs[i].sh_size;
 896         }
 897
 898         return 0;
 899 }
 900
 901 static int kexec_apply_relocations(struct kimage *image)
 902 {
 903         int i, ret;
 904         struct purgatory_info *pi = &image->purgatory_info;
 905         const Elf_Shdr *sechdrs;
 906
 907         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 908
 909         for (i = 0; i < pi->ehdr->e_shnum; i++) {
 910                 const Elf_Shdr *relsec;
 911                 const Elf_Shdr *symtab;
 912                 Elf_Shdr *section;
 913
 914                 relsec = sechdrs + i;
 915
 916                 if (relsec->sh_type != SHT_RELA &&
 917                     relsec->sh_type != SHT_REL)
 918                         continue;
 919
 920                 /*
 921                  * For section of type SHT_RELA/SHT_REL,
 922                  * ->sh_link contains section header index of associated
 923                  * symbol table. And ->sh_info contains section header
 924                  * index of section to which relocations apply.
 925                  */
 926                 if (relsec->sh_info >= pi->ehdr->e_shnum ||
 927                     relsec->sh_link >= pi->ehdr->e_shnum)
 928                         return -ENOEXEC;
 929
 930                 section = pi->sechdrs + relsec->sh_info;
 931                 symtab = sechdrs + relsec->sh_link;
 932
 933                 if (!(section->sh_flags & SHF_ALLOC))
 934                         continue;
 935
 936                 /*
 937                  * symtab->sh_link contain section header index of associated
 938                  * string table.
 939                  */
 940                 if (symtab->sh_link >= pi->ehdr->e_shnum)
 941                         /* Invalid section number? */
 942                         continue;
 943
 944                 /*
 945                  * Respective architecture needs to provide support for applying
 946                  * relocations of type SHT_RELA/SHT_REL.
 947                  */
 948                 if (relsec->sh_type == SHT_RELA)
 949                         ret = arch_kexec_apply_relocations_add(pi, section,
 950                                                                relsec, symtab);
 951                 else if (relsec->sh_type == SHT_REL)
 952                         ret = arch_kexec_apply_relocations(pi, section,
 953                                                            relsec, symtab);
 954                 if (ret)
 955                         return ret;
 956         }
 957
 958         return 0;
 959 }
 960
 961 /*
 962  * kexec_load_purgatory - Load and relocate the purgatory object.
 963  * @image:      Image to add the purgatory to.
 964  * @kbuf:       Memory parameters to use.
 965  *
 966  * Allocates the memory needed for image->purgatory_info.sechdrs and
 967  * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
 968  * to free the memory after use.
 969  *
 970  * Return: 0 on success, negative errno on error.
 971  */
 972 int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
 973 {
 974         struct purgatory_info *pi = &image->purgatory_info;
 975         int ret;
 976
 977         if (kexec_purgatory_size <= 0)
 978                 return -EINVAL;
 979
 980         pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
 981
 982         ret = kexec_purgatory_setup_kbuf(pi, kbuf);
 983         if (ret)
 984                 return ret;
 985
 986         ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
 987         if (ret)
 988                 goto out_free_kbuf;
 989
 990         ret = kexec_apply_relocations(image);
 991         if (ret)
 992                 goto out;
 993
 994         return 0;
 995 out:
 996         vfree(pi->sechdrs);
 997         pi->sechdrs = NULL;
 998 out_free_kbuf:
 999         vfree(pi->purgatory_buf);
1000         pi->purgatory_buf = NULL;
1001         return ret;
1002 }
1003
1004 /*
1005  * kexec_purgatory_find_symbol - find a symbol in the purgatory
1006  * @pi:         Purgatory to search in.
1007  * @name:       Name of the symbol.
1008  *
1009  * Return: pointer to symbol in read-only symtab on success, NULL on error.
1010  */
1011 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1012                                                   const char *name)
1013 {
1014         const Elf_Shdr *sechdrs;
1015         const Elf_Ehdr *ehdr;
1016         const Elf_Sym *syms;
1017         const char *strtab;
1018         int i, k;
1019
1020         if (!pi->ehdr)
1021                 return NULL;
1022
1023         ehdr = pi->ehdr;
1024         sechdrs = (void *)ehdr + ehdr->e_shoff;
1025
1026         for (i = 0; i < ehdr->e_shnum; i++) {
1027                 if (sechdrs[i].sh_type != SHT_SYMTAB)
1028                         continue;
1029
1030                 if (sechdrs[i].sh_link >= ehdr->e_shnum)
1031                         /* Invalid strtab section number */
1032                         continue;
1033                 strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
1034                 syms = (void *)ehdr + sechdrs[i].sh_offset;
1035
1036                 /* Go through symbols for a match */
1037                 for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
1038                         if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
1039                                 continue;
1040
1041                         if (strcmp(strtab + syms[k].st_name, name) != 0)
1042                                 continue;
1043
1044                         if (syms[k].st_shndx == SHN_UNDEF ||
1045                             syms[k].st_shndx >= ehdr->e_shnum) {
1046                                 pr_debug("Symbol: %s has bad section index %d.\n",
1047                                                 name, syms[k].st_shndx);
1048                                 return NULL;
1049                         }
1050
1051                         /* Found the symbol we are looking for */
1052                         return &syms[k];
1053                 }
1054         }
1055
1056         return NULL;
1057 }
1058
1059 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
1060 {
1061         struct purgatory_info *pi = &image->purgatory_info;
1062         const Elf_Sym *sym;
1063         Elf_Shdr *sechdr;
1064
1065         sym = kexec_purgatory_find_symbol(pi, name);
1066         if (!sym)
1067                 return ERR_PTR(-EINVAL);
1068
1069         sechdr = &pi->sechdrs[sym->st_shndx];
1070
1071         /*
1072          * Returns the address where symbol will finally be loaded after
1073          * kexec_load_segment()
1074          */
1075         return (void *)(sechdr->sh_addr + sym->st_value);
1076 }
1077
1078 /*
1079  * Get or set value of a symbol. If "get_value" is true, symbol value is
1080  * returned in buf otherwise symbol value is set based on value in buf.
1081  */
1082 int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
1083                                    void *buf, unsigned int size, bool get_value)
1084 {
1085         struct purgatory_info *pi = &image->purgatory_info;
1086         const Elf_Sym *sym;
1087         Elf_Shdr *sec;
1088         char *sym_buf;
1089
1090         sym = kexec_purgatory_find_symbol(pi, name);
1091         if (!sym)
1092                 return -EINVAL;
1093
1094         if (sym->st_size != size) {
1095                 pr_err("symbol %s size mismatch: expected %lu actual %u\n",
1096                        name, (unsigned long)sym->st_size, size);
1097                 return -EINVAL;
1098         }
1099
1100         sec = pi->sechdrs + sym->st_shndx;
1101
1102         if (sec->sh_type == SHT_NOBITS) {
1103                 pr_err("symbol %s is in a bss section. Cannot %s\n", name,
1104                        get_value ? "get" : "set");
1105                 return -EINVAL;
1106         }
1107
1108         sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
1109
1110         if (get_value)
1111                 memcpy((void *)buf, sym_buf, size);
1112         else
1113                 memcpy((void *)sym_buf, buf, size);
1114
1115         return 0;
1116 }
1117 #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
1118
1119 int crash_exclude_mem_range(struct crash_mem *mem,
1120                             unsigned long long mstart, unsigned long long mend)
1121 {
1122         int i, j;
1123         unsigned long long start, end;
1124         struct crash_mem_range temp_range = {0, 0};
1125
1126         for (i = 0; i < mem->nr_ranges; i++) {
1127                 start = mem->ranges[i].start;
1128                 end = mem->ranges[i].end;
1129
1130                 if (mstart > end || mend < start)
1131                         continue;
1132
1133                 /* Truncate any area outside of range */
1134                 if (mstart < start)
1135                         mstart = start;
1136                 if (mend > end)
1137                         mend = end;
1138
1139                 /* Found completely overlapping range */
1140                 if (mstart == start && mend == end) {
1141                         mem->ranges[i].start = 0;
1142                         mem->ranges[i].end = 0;
1143                         if (i < mem->nr_ranges - 1) {
1144                                 /* Shift rest of the ranges to left */
1145                                 for (j = i; j < mem->nr_ranges - 1; j++) {
1146                                         mem->ranges[j].start =
1147                                                 mem->ranges[j+1].start;
1148                                         mem->ranges[j].end =
1149                                                         mem->ranges[j+1].end;
1150                                 }
1151                         }
1152                         mem->nr_ranges--;
1153                         return 0;
1154                 }
1155
1156                 if (mstart > start && mend < end) {
1157                         /* Split original range */
1158                         mem->ranges[i].end = mstart - 1;
1159                         temp_range.start = mend + 1;
1160                         temp_range.end = end;
1161                 } else if (mstart != start)
1162                         mem->ranges[i].end = mstart - 1;
1163                 else
1164                         mem->ranges[i].start = mend + 1;
1165                 break;
1166         }
1167
1168         /* If a split happened, add the split to array */
1169         if (!temp_range.end)
1170                 return 0;
1171
1172         /* Split happened */
1173         if (i == mem->max_nr_ranges - 1)
1174                 return -ENOMEM;
1175
1176         /* Location where new range should go */
1177         j = i + 1;
1178         if (j < mem->nr_ranges) {
1179                 /* Move over all ranges one slot towards the end */
1180                 for (i = mem->nr_ranges - 1; i >= j; i--)
1181                         mem->ranges[i + 1] = mem->ranges[i];
1182         }
1183
1184         mem->ranges[j].start = temp_range.start;
1185         mem->ranges[j].end = temp_range.end;
1186         mem->nr_ranges++;
1187         return 0;
1188 }
1189
1190 int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
1191                           void **addr, unsigned long *sz)
1192 {
1193         Elf64_Ehdr *ehdr;
1194         Elf64_Phdr *phdr;
1195         unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
1196         unsigned char *buf;
1197         unsigned int cpu, i;
1198         unsigned long long notes_addr;
1199         unsigned long mstart, mend;
1200
1201         /* extra phdr for vmcoreinfo elf note */
1202         nr_phdr = nr_cpus + 1;
1203         nr_phdr += mem->nr_ranges;
1204
1205         /*
1206          * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
1207          * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
1208          * I think this is required by tools like gdb. So same physical
1209          * memory will be mapped in two elf headers. One will contain kernel
1210          * text virtual addresses and other will have __va(physical) addresses.
1211          */
1212
1213         nr_phdr++;
1214         elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
1215         elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
1216
1217         buf = vzalloc(elf_sz);
1218         if (!buf)
1219                 return -ENOMEM;
1220
1221         ehdr = (Elf64_Ehdr *)buf;
1222         phdr = (Elf64_Phdr *)(ehdr + 1);
1223         memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
1224         ehdr->e_ident[EI_CLASS] = ELFCLASS64;
1225         ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
1226         ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1227         ehdr->e_ident[EI_OSABI] = ELF_OSABI;
1228         memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
1229         ehdr->e_type = ET_CORE;
1230         ehdr->e_machine = ELF_ARCH;
1231         ehdr->e_version = EV_CURRENT;
1232         ehdr->e_phoff = sizeof(Elf64_Ehdr);
1233         ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1234         ehdr->e_phentsize = sizeof(Elf64_Phdr);
1235
1236         /* Prepare one phdr of type PT_NOTE for each present cpu */
1237         for_each_present_cpu(cpu) {
1238                 phdr->p_type = PT_NOTE;
1239                 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
1240                 phdr->p_offset = phdr->p_paddr = notes_addr;
1241                 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
1242                 (ehdr->e_phnum)++;
1243                 phdr++;
1244         }
1245
1246         /* Prepare one PT_NOTE header for vmcoreinfo */
1247         phdr->p_type = PT_NOTE;
1248         phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
1249         phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
1250         (ehdr->e_phnum)++;
1251         phdr++;
1252
1253         /* Prepare PT_LOAD type program header for kernel text region */
1254         if (kernel_map) {
1255                 phdr->p_type = PT_LOAD;
1256                 phdr->p_flags = PF_R|PF_W|PF_X;
1257                 phdr->p_vaddr = (Elf64_Addr)_text;
1258                 phdr->p_filesz = phdr->p_memsz = _end - _text;
1259                 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
1260                 ehdr->e_phnum++;
1261                 phdr++;
1262         }
1263
1264         /* Go through all the ranges in mem->ranges[] and prepare phdr */
1265         for (i = 0; i < mem->nr_ranges; i++) {
1266                 mstart = mem->ranges[i].start;
1267                 mend = mem->ranges[i].end;
1268
1269                 phdr->p_type = PT_LOAD;
1270                 phdr->p_flags = PF_R|PF_W|PF_X;
1271                 phdr->p_offset  = mstart;
1272
1273                 phdr->p_paddr = mstart;
1274                 phdr->p_vaddr = (unsigned long long) __va(mstart);
1275                 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
1276                 phdr->p_align = 0;
1277                 ehdr->e_phnum++;
1278                 phdr++;
1279                 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",
1280                         phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
1281                         ehdr->e_phnum, phdr->p_offset);
1282         }
1283
1284         *addr = buf;
1285         *sz = elf_sz;
1286         return 0;
1287 }