1 /* Copyright 2019 The ChromiumOS Authors
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 *
5 * Firmware management parameters (FWMP) APIs
6 */
7
8 #include "2common.h"
9 #include "2crc8.h"
10 #include "2misc.h"
11 #include "2secdata.h"
12 #include "2secdata_struct.h"
13
14 test_mockable
vb2api_secdata_fwmp_check(struct vb2_context * ctx,uint8_t * size)15 vb2_error_t vb2api_secdata_fwmp_check(struct vb2_context *ctx, uint8_t *size)
16 {
17 struct vb2_secdata_fwmp *sec =
18 (struct vb2_secdata_fwmp *)&ctx->secdata_fwmp;
19
20 /* Verify that at least the minimum size has been read */
21 if (*size < VB2_SECDATA_FWMP_MIN_SIZE) {
22 VB2_DEBUG("FWMP: missing %d bytes for minimum size\n",
23 VB2_SECDATA_FWMP_MIN_SIZE - *size);
24 *size = VB2_SECDATA_FWMP_MIN_SIZE;
25 return VB2_ERROR_SECDATA_FWMP_INCOMPLETE;
26 }
27
28 /* Verify that struct_size is reasonable */
29 if (sec->struct_size < VB2_SECDATA_FWMP_MIN_SIZE ||
30 sec->struct_size > VB2_SECDATA_FWMP_MAX_SIZE) {
31 VB2_DEBUG("FWMP: invalid size: %d\n", sec->struct_size);
32 return VB2_ERROR_SECDATA_FWMP_SIZE;
33 }
34
35 /* Verify that we have read full structure */
36 if (*size < sec->struct_size) {
37 VB2_DEBUG("FWMP: missing %d bytes\n", sec->struct_size - *size);
38 *size = sec->struct_size;
39 return VB2_ERROR_SECDATA_FWMP_INCOMPLETE;
40 }
41 *size = sec->struct_size;
42
43 /* Verify CRC */
44 if (sec->crc8 != vb2_secdata_fwmp_crc(sec)) {
45 VB2_DEBUG("FWMP: bad CRC\n");
46 return VB2_ERROR_SECDATA_FWMP_CRC;
47 }
48
49 /* Verify major version is compatible */
50 if ((sec->struct_version >> 4) != (VB2_SECDATA_FWMP_VERSION >> 4)) {
51 VB2_DEBUG("FWMP: major version incompatible\n");
52 return VB2_ERROR_SECDATA_FWMP_VERSION;
53 }
54
55 /*
56 * If this were a 1.1+ reader and the source was a 1.0 struct,
57 * we would need to take care of initializing the extra fields
58 * added in 1.1+. But that's not an issue yet.
59 */
60 return VB2_SUCCESS;
61 }
62
vb2api_secdata_fwmp_create(struct vb2_context * ctx)63 uint32_t vb2api_secdata_fwmp_create(struct vb2_context *ctx)
64 {
65 struct vb2_secdata_fwmp *sec = (void *)&ctx->secdata_fwmp;
66
67 /* Clear the entire struct */
68 memset(sec, 0, sizeof(*sec));
69
70 /* Set to current version */
71 sec->struct_version = VB2_SECDATA_FWMP_VERSION;
72
73 /* Set the structure size */
74 sec->struct_size = sizeof(*sec);
75
76 /* Calculate initial CRC */
77 sec->crc8 = vb2_secdata_fwmp_crc(sec);
78
79 return sizeof(*sec);
80 }
81
82 test_mockable
vb2_secdata_fwmp_init(struct vb2_context * ctx)83 vb2_error_t vb2_secdata_fwmp_init(struct vb2_context *ctx)
84 {
85 struct vb2_shared_data *sd = vb2_get_sd(ctx);
86 struct vb2_secdata_fwmp *sec =
87 (struct vb2_secdata_fwmp *)&ctx->secdata_fwmp;
88
89 /* Skip checking if NO_SECDATA_FWMP is set. */
90 if (!(ctx->flags & VB2_CONTEXT_NO_SECDATA_FWMP))
91 VB2_TRY(vb2api_secdata_fwmp_check(ctx, &sec->struct_size));
92
93 /* Mark as initialized */
94 sd->status |= VB2_SD_STATUS_SECDATA_FWMP_INIT;
95
96 return VB2_SUCCESS;
97 }
98
vb2_secdata_fwmp_get_flag(struct vb2_context * ctx,enum vb2_secdata_fwmp_flags flag)99 int vb2_secdata_fwmp_get_flag(struct vb2_context *ctx,
100 enum vb2_secdata_fwmp_flags flag)
101 {
102 struct vb2_shared_data *sd = vb2_get_sd(ctx);
103 struct vb2_secdata_fwmp *sec =
104 (struct vb2_secdata_fwmp *)&ctx->secdata_fwmp;
105
106 if (!(sd->status & VB2_SD_STATUS_SECDATA_FWMP_INIT)) {
107 VB2_REC_OR_DIE(ctx, "Must init FWMP before retrieving flag\n");
108 return 0;
109 }
110
111 if (ctx->flags & VB2_CONTEXT_NO_SECDATA_FWMP)
112 return 0;
113
114 return !!(sec->flags & flag);
115 }
116
vb2_secdata_fwmp_get_dev_key_hash(struct vb2_context * ctx)117 uint8_t *vb2_secdata_fwmp_get_dev_key_hash(struct vb2_context *ctx)
118 {
119 struct vb2_shared_data *sd = vb2_get_sd(ctx);
120 struct vb2_secdata_fwmp *sec =
121 (struct vb2_secdata_fwmp *)&ctx->secdata_fwmp;
122
123 if (!(sd->status & VB2_SD_STATUS_SECDATA_FWMP_INIT)) {
124 VB2_REC_OR_DIE(ctx, "Must init FWMP before get dev key hash\n");
125 return NULL;
126 }
127
128 if (ctx->flags & VB2_CONTEXT_NO_SECDATA_FWMP)
129 return NULL;
130
131 return sec->dev_key_hash;
132 }
133