Cregit: Linux 5.8: purgatory.c

Contributors: 6
Author	Tokens	Token Proportion	Commits	Commit Proportion
Vivek Goyal	135	74.59%	1	12.50%
Thomas Gleixner	31	17.13%	2	25.00%
Nick Desaulniers	10	5.52%	1	12.50%
Tobin C Harding	3	1.66%	2	25.00%
Hans de Goede	1	0.55%	1	12.50%
Philipp Rudo	1	0.55%	1	12.50%
Total	181		8

// SPDX-License-Identifier: GPL-2.0-only
/*
 * purgatory: Runs between two kernels
 *
 * Copyright (C) 2014 Red Hat Inc.
 *
 * Author:
 *       Vivek Goyal <vgoyal@redhat.com>
 */

#include <linux/bug.h>
#include <crypto/sha.h>
#include <asm/purgatory.h>

#include "../boot/string.h"

u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(.kexec-purgatory);

struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(.kexec-purgatory);

static int verify_sha256_digest(void)
{
	struct kexec_sha_region *ptr, *end;
	u8 digest[SHA256_DIGEST_SIZE];
	struct sha256_state sctx;

	sha256_init(&sctx);
	end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);

	for (ptr = purgatory_sha_regions; ptr < end; ptr++)
		sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);

	sha256_final(&sctx, digest);

	if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
		return 1;

	return 0;
}

void purgatory(void)
{
	int ret;

	ret = verify_sha256_digest();
	if (ret) {
		/* loop forever */
		for (;;)
			;
	}
}

/*
 * Defined in order to reuse memcpy() and memset() from
 * arch/x86/boot/compressed/string.c
 */
void warn(const char *msg) {}