| 1 | // SPDX-License-Identifier: GPL-2.0-only |
|---|---|
| 2 | /* |
| 3 | * purgatory: Runs between two kernels |
| 4 | * |
| 5 | * Copyright (C) 2022 Huawei Technologies Co, Ltd. |
| 6 | * |
| 7 | * Author: Li Zhengyu (lizhengyu3@huawei.com) |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/purgatory.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/string.h> |
| 14 | #include <asm/string.h> |
| 15 | |
| 16 | u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory"); |
| 17 | |
| 18 | struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory"); |
| 19 | |
| 20 | static int verify_sha256_digest(void) |
| 21 | { |
| 22 | struct kexec_sha_region *ptr, *end; |
| 23 | struct sha256_state ss; |
| 24 | u8 digest[SHA256_DIGEST_SIZE]; |
| 25 | |
| 26 | sha256_init(sctx: &ss); |
| 27 | end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions); |
| 28 | for (ptr = purgatory_sha_regions; ptr < end; ptr++) |
| 29 | sha256_update(sctx: &ss, data: (uint8_t *)(ptr->start), len: ptr->len); |
| 30 | sha256_final(sctx: &ss, out: digest); |
| 31 | if (memcmp(p: digest, q: purgatory_sha256_digest, size: sizeof(digest)) != 0) |
| 32 | return 1; |
| 33 | return 0; |
| 34 | } |
| 35 | |
| 36 | /* workaround for a warning with -Wmissing-prototypes */ |
| 37 | void purgatory(void); |
| 38 | |
| 39 | void purgatory(void) |
| 40 | { |
| 41 | if (verify_sha256_digest()) |
| 42 | for (;;) |
| 43 | /* loop forever */ |
| 44 | ; |
| 45 | } |
| 46 |