| 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: &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: &sctx, data: (uint8_t *)(ptr->start), len: ptr->len); |
| 35 | |
| 36 | sha256_final(sctx: &sctx, out: 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 |