purgatory.c (1221B)
1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * purgatory: Runs between two kernels 4 * 5 * Copyright (C) 2014 Red Hat Inc. 6 * 7 * Author: 8 * Vivek Goyal <vgoyal@redhat.com> 9 */ 10 11#include <linux/bug.h> 12#include <linux/kernel.h> 13#include <linux/types.h> 14#include <crypto/sha2.h> 15#include <asm/purgatory.h> 16 17#include "../boot/string.h" 18 19u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory"); 20 21struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory"); 22 23static int verify_sha256_digest(void) 24{ 25 struct kexec_sha_region *ptr, *end; 26 u8 digest[SHA256_DIGEST_SIZE]; 27 struct sha256_state sctx; 28 29 sha256_init(&sctx); 30 end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions); 31 32 for (ptr = purgatory_sha_regions; ptr < end; ptr++) 33 sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len); 34 35 sha256_final(&sctx, digest); 36 37 if (memcmp(digest, purgatory_sha256_digest, sizeof(digest))) 38 return 1; 39 40 return 0; 41} 42 43void purgatory(void) 44{ 45 int ret; 46 47 ret = verify_sha256_digest(); 48 if (ret) { 49 /* loop forever */ 50 for (;;) 51 ; 52 } 53} 54 55/* 56 * Defined in order to reuse memcpy() and memset() from 57 * arch/x86/boot/compressed/string.c 58 */ 59void warn(const char *msg) {}