1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
/*
* Copyright 2020 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* SHA256 module for Chrome EC */
#include "common.h"
#include "sha256.h"
#include "util.h"
enum ncl_status {
NCL_STATUS_OK,
NCL_STATUS_FAIL,
NCL_STATUS_INVALID_PARAM,
NCL_STATUS_PARAM_NOT_SUPPORTED,
NCL_STATUS_SYSTEM_BUSY,
NCL_STATUS_AUTHENTICATION_FAIL,
NCL_STATUS_NO_RESPONSE,
NCL_STATUS_HARDWARE_ERROR,
};
enum ncl_sha_type {
NCL_SHA_TYPE_2_256 = 0,
NCL_SHA_TYPE_2_384 = 1,
NCL_SHA_TYPE_2_512 = 2,
NCL_SHA_TYPE_NUM
};
/*
* The base address of the table that holds the function pointer for each
* SHA256 API in ROM.
*/
#define NCL_SHA_BASE_ADDR 0x00000100UL
struct ncl_sha {
/* Get the SHA context size required by SHA APIs. */
uint32_t (*get_context_size)(void);
/* Initial SHA context. */
enum ncl_status (*init_context)(void *ctx);
/* Finalize SHA context. */
enum ncl_status (*finalize_context)(void *ctx);
/* Initiate the SHA hardware module and setups needed parameters. */
enum ncl_status (*init)(void *ctx);
/*
* Prepare the context buffer for a SHA calculation - by loading the
* initial SHA-256/384/512 parameters.
*/
enum ncl_status (*start)(void *ctx, enum ncl_sha_type type);
/*
* Updates the SHA calculation with the additional data. When the
* function returns, the hardware and memory buffer shall be ready to
* accept new data * buffers for SHA calculation and changes to the data
* in data buffer should no longer effect the SHA calculation.
*/
enum ncl_status (*update)(void *ctx, const uint8_t *data, uint32_t Len);
/* Return the SHA result (digest.) */
enum ncl_status (*finish)(void *ctx, uint8_t *hashDigest);
/* Perform a complete SHA calculation */
enum ncl_status (*calc)(void *ctx, enum ncl_sha_type type,
const uint8_t *data, uint32_t Len, uint8_t *hashDigest);
/* Power on/off the SHA module. */
enum ncl_status (*power)(void *ctx, uint8_t enable);
/* Reset the SHA hardware and terminate any in-progress operations. */
enum ncl_status (*reset)(void *ctx);
};
#define NCL_SHA ((const struct ncl_sha *)NCL_SHA_BASE_ADDR)
void SHA256_init(struct sha256_ctx *ctx)
{
NCL_SHA->init_context(ctx->handle);
NCL_SHA->power(ctx->handle, 1);
NCL_SHA->init(ctx->handle);
NCL_SHA->reset(ctx->handle);
NCL_SHA->start(ctx->handle, NCL_SHA_TYPE_2_256);
}
void SHA256_update(struct sha256_ctx *ctx, const uint8_t *data, uint32_t len)
{
NCL_SHA->update(ctx->handle, data, len);
}
void SHA256_abort(struct sha256_ctx *ctx)
{
NCL_SHA->reset(ctx->handle);
NCL_SHA->power(ctx->handle, 0);
NCL_SHA->finalize_context(ctx->handle);
}
uint8_t *SHA256_final(struct sha256_ctx *ctx)
{
NCL_SHA->finish(ctx->handle, ctx->buf);
NCL_SHA->power(ctx->handle, 0);
NCL_SHA->finalize_context(ctx->handle);
return ctx->buf;
}
static void hmac_SHA256_step(uint8_t *output, uint8_t mask,
const uint8_t *key, const int key_len,
const uint8_t *data, const int data_len)
{
struct sha256_ctx hmac_ctx;
uint8_t *key_pad = hmac_ctx.buf;
uint8_t *tmp;
int i;
memset(key_pad, mask, SHA256_BLOCK_SIZE);
for (i = 0; i < key_len; i++)
key_pad[i] ^= key[i];
SHA256_init(&hmac_ctx);
SHA256_update(&hmac_ctx, key_pad, SHA256_BLOCK_SIZE);
SHA256_update(&hmac_ctx, data, data_len);
tmp = SHA256_final(&hmac_ctx);
memcpy(output, tmp, SHA256_DIGEST_SIZE);
}
/*
* Note: When the API is called, it will consume about half of TASK_STACK_SIZE
* because a variable of structure sha256_ctx is declared in the function
* hmac_SHA256_step.
*/
void hmac_SHA256(uint8_t *output, const uint8_t *key, const int key_len,
const uint8_t *message, const int message_len)
{
/* This code does not support key_len > block_size. */
ASSERT(key_len <= SHA256_BLOCK_SIZE);
/*
* i_key_pad = key (zero-padded) ^ 0x36
* output = hash(i_key_pad || message)
* (Use output as temporary buffer)
*/
hmac_SHA256_step(output, 0x36, key, key_len, message, message_len);
/*
* o_key_pad = key (zero-padded) ^ 0x5c
* output = hash(o_key_pad || output)
*/
hmac_SHA256_step(output, 0x5c, key, key_len, output,
SHA256_DIGEST_SIZE);
}
|
