LXR linux/arch/s390/purgatory/purgatory.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Purgatory code running between two kernels.
   4 *
   5 * Copyright IBM Corp. 2018
   6 *
   7 * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
   8 */
   9
  10#include <linux/kexec.h>
  11#include <linux/string.h>
  12#include <crypto/sha2.h>
  13#include <asm/purgatory.h>
  14
  15int verify_sha256_digest(void)
  16{
  17        struct kexec_sha_region *ptr, *end;
  18        u8 digest[SHA256_DIGEST_SIZE];
  19        struct sha256_state sctx;
  20
  21        sha256_init(&sctx);
  22        end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
  23
  24        for (ptr = purgatory_sha_regions; ptr < end; ptr++)
  25                sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
  26
  27        sha256_final(&sctx, digest);
  28
  29        if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
  30                return 1;
  31
  32        return 0;
  33}
  34