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/compressed/error.h"
18 #include "../boot/string.h"
19
20 u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
21
22 struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");
23
24 static int verify_sha256_digest(void)
25 {
26 struct kexec_sha_region *ptr, *end;
27 u8 digest[SHA256_DIGEST_SIZE];
28 struct sha256_state sctx;
29
30 sha256_init(&sctx);
31 end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
32
33 for (ptr = purgatory_sha_regions; ptr < end; ptr++)
34 sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
35
36 sha256_final(&sctx, digest);
37
38 if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
39 return 1;
40
41 return 0;
42 }
43
44 void purgatory(void)
45 {
46 int ret;
47
48 ret = verify_sha256_digest();
49 if (ret) {
50 /* loop forever */
51 for (;;)
52 ;
53 }
54 }
55
56 /*
57 * Defined in order to reuse memcpy() and memset() from
58 * arch/x86/boot/compressed/string.c
59 */
60 void warn(const char *msg) {}
61
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