1 /* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 */
5
6 /* Non-volatile storage routines */
7
8 #include "2sysincludes.h"
9 #include "2common.h"
10 #include "2crc8.h"
11 #include "2misc.h"
12 #include "2nvstorage.h"
13 #include "2nvstorage_fields.h"
14
vb2_nv_regen_crc(struct vb2_context * ctx)15 static void vb2_nv_regen_crc(struct vb2_context *ctx)
16 {
17 ctx->nvdata[VB2_NV_OFFS_CRC] = vb2_crc8(ctx->nvdata, VB2_NV_OFFS_CRC);
18 ctx->flags |= VB2_CONTEXT_NVDATA_CHANGED;
19 }
20
21 /**
22 * Check the CRC of the non-volatile storage context.
23 *
24 * Use this if reading from non-volatile storage may be flaky, and you want to
25 * retry reading it several times.
26 *
27 * This may be called before vb2_context_init().
28 *
29 * @param ctx Context pointer
30 * @return VB2_SUCCESS, or non-zero error code if error.
31 */
vb2_nv_check_crc(const struct vb2_context * ctx)32 int vb2_nv_check_crc(const struct vb2_context *ctx)
33 {
34 const uint8_t *p = ctx->nvdata;
35
36 /* Check header */
37 if (VB2_NV_HEADER_SIGNATURE !=
38 (p[VB2_NV_OFFS_HEADER] & VB2_NV_HEADER_MASK))
39 return VB2_ERROR_NV_HEADER;
40
41 /* Check CRC */
42 if (vb2_crc8(p, VB2_NV_OFFS_CRC) != p[VB2_NV_OFFS_CRC])
43 return VB2_ERROR_NV_CRC;
44
45 return VB2_SUCCESS;
46 }
47
vb2_nv_init(struct vb2_context * ctx)48 void vb2_nv_init(struct vb2_context *ctx)
49 {
50 struct vb2_shared_data *sd = vb2_get_sd(ctx);
51 uint8_t *p = ctx->nvdata;
52
53 /* Check data for consistency */
54 if (vb2_nv_check_crc(ctx) != VB2_SUCCESS) {
55 /* Data is inconsistent (bad CRC or header); reset defaults */
56 memset(p, 0, VB2_NVDATA_SIZE);
57 p[VB2_NV_OFFS_HEADER] = (VB2_NV_HEADER_SIGNATURE |
58 VB2_NV_HEADER_FW_SETTINGS_RESET |
59 VB2_NV_HEADER_KERNEL_SETTINGS_RESET);
60
61 /* Regenerate CRC */
62 vb2_nv_regen_crc(ctx);
63
64 /* Set status flag */
65 sd->status |= VB2_SD_STATUS_NV_REINIT;
66 // TODO: unit test for status flag being set
67 }
68
69 sd->status |= VB2_SD_STATUS_NV_INIT;
70 }
71
72 /* Macro for vb2_nv_get() single-bit settings to reduce duplicate code. */
73 #define GETBIT(offs, mask) (p[offs] & mask ? 1 : 0)
74
vb2_nv_get(struct vb2_context * ctx,enum vb2_nv_param param)75 uint32_t vb2_nv_get(struct vb2_context *ctx, enum vb2_nv_param param)
76 {
77 const uint8_t *p = ctx->nvdata;
78
79 /*
80 * TODO: We could reduce the binary size for this code by #ifdef'ing
81 * out the params not used by firmware verification.
82 */
83 switch (param) {
84 case VB2_NV_FIRMWARE_SETTINGS_RESET:
85 return GETBIT(VB2_NV_OFFS_HEADER,
86 VB2_NV_HEADER_FW_SETTINGS_RESET);
87
88 case VB2_NV_KERNEL_SETTINGS_RESET:
89 return GETBIT(VB2_NV_OFFS_HEADER,
90 VB2_NV_HEADER_KERNEL_SETTINGS_RESET);
91
92 case VB2_NV_DEBUG_RESET_MODE:
93 return GETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_DEBUG_RESET);
94
95 case VB2_NV_TRY_NEXT:
96 return GETBIT(VB2_NV_OFFS_BOOT2, VB2_NV_BOOT2_TRY_NEXT);
97
98 case VB2_NV_TRY_COUNT:
99 return p[VB2_NV_OFFS_BOOT] & VB2_NV_BOOT_TRY_COUNT_MASK;
100
101 case VB2_NV_FW_TRIED:
102 return GETBIT(VB2_NV_OFFS_BOOT2, VB2_NV_BOOT2_TRIED);
103
104 case VB2_NV_FW_RESULT:
105 return p[VB2_NV_OFFS_BOOT2] & VB2_NV_BOOT2_RESULT_MASK;
106
107 case VB2_NV_FW_PREV_TRIED:
108 return GETBIT(VB2_NV_OFFS_BOOT2, VB2_NV_BOOT2_PREV_TRIED);
109
110 case VB2_NV_FW_PREV_RESULT:
111 return (p[VB2_NV_OFFS_BOOT2] & VB2_NV_BOOT2_PREV_RESULT_MASK)
112 >> VB2_NV_BOOT2_PREV_RESULT_SHIFT;
113
114 case VB2_NV_RECOVERY_REQUEST:
115 return p[VB2_NV_OFFS_RECOVERY];
116
117 case VB2_NV_RECOVERY_SUBCODE:
118 return p[VB2_NV_OFFS_RECOVERY_SUBCODE];
119
120 case VB2_NV_LOCALIZATION_INDEX:
121 return p[VB2_NV_OFFS_LOCALIZATION];
122
123 case VB2_NV_KERNEL_FIELD:
124 return (p[VB2_NV_OFFS_KERNEL]
125 | (p[VB2_NV_OFFS_KERNEL + 1] << 8)
126 | (p[VB2_NV_OFFS_KERNEL + 2] << 16)
127 | (p[VB2_NV_OFFS_KERNEL + 3] << 24));
128
129 case VB2_NV_DEV_BOOT_USB:
130 return GETBIT(VB2_NV_OFFS_DEV, VB2_NV_DEV_FLAG_USB);
131
132 case VB2_NV_DEV_BOOT_LEGACY:
133 return GETBIT(VB2_NV_OFFS_DEV, VB2_NV_DEV_FLAG_LEGACY);
134
135 case VB2_NV_DEV_BOOT_SIGNED_ONLY:
136 return GETBIT(VB2_NV_OFFS_DEV, VB2_NV_DEV_FLAG_SIGNED_ONLY);
137
138 case VB2_NV_DISABLE_DEV_REQUEST:
139 return GETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_DISABLE_DEV);
140
141 case VB2_NV_OPROM_NEEDED:
142 return GETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_OPROM_NEEDED);
143
144 case VB2_NV_BACKUP_NVRAM_REQUEST:
145 return GETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_BACKUP_NVRAM);
146
147 case VB2_NV_CLEAR_TPM_OWNER_REQUEST:
148 return GETBIT(VB2_NV_OFFS_TPM, VB2_NV_TPM_CLEAR_OWNER_REQUEST);
149
150 case VB2_NV_CLEAR_TPM_OWNER_DONE:
151 return GETBIT(VB2_NV_OFFS_TPM, VB2_NV_TPM_CLEAR_OWNER_DONE);
152 }
153
154 /*
155 * Put default return outside the switch() instead of in default:, so
156 * that adding a new param will cause a compiler warning.
157 */
158 return 0;
159 }
160
161 #undef GETBIT
162
163 /* Macro for vb2_nv_set() single-bit settings to reduce duplicate code. */
164 #define SETBIT(offs, mask) \
165 { if (value) p[offs] |= mask; else p[offs] &= ~mask; }
166
vb2_nv_set(struct vb2_context * ctx,enum vb2_nv_param param,uint32_t value)167 void vb2_nv_set(struct vb2_context *ctx,
168 enum vb2_nv_param param,
169 uint32_t value)
170 {
171 uint8_t *p = ctx->nvdata;
172
173 /* If not changing the value, don't regenerate the CRC. */
174 if (vb2_nv_get(ctx, param) == value)
175 return;
176
177 /*
178 * TODO: We could reduce the binary size for this code by #ifdef'ing
179 * out the params not used by firmware verification.
180 */
181 switch (param) {
182 case VB2_NV_FIRMWARE_SETTINGS_RESET:
183 SETBIT(VB2_NV_OFFS_HEADER, VB2_NV_HEADER_FW_SETTINGS_RESET);
184 break;
185
186 case VB2_NV_KERNEL_SETTINGS_RESET:
187 SETBIT(VB2_NV_OFFS_HEADER, VB2_NV_HEADER_KERNEL_SETTINGS_RESET);
188 break;
189
190 case VB2_NV_DEBUG_RESET_MODE:
191 SETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_DEBUG_RESET);
192 break;
193
194 case VB2_NV_TRY_NEXT:
195 SETBIT(VB2_NV_OFFS_BOOT2, VB2_NV_BOOT2_TRY_NEXT);
196 break;
197
198 case VB2_NV_TRY_COUNT:
199 /* Clip to valid range. */
200 if (value > VB2_NV_BOOT_TRY_COUNT_MASK)
201 value = VB2_NV_BOOT_TRY_COUNT_MASK;
202
203 p[VB2_NV_OFFS_BOOT] &= ~VB2_NV_BOOT_TRY_COUNT_MASK;
204 p[VB2_NV_OFFS_BOOT] |= (uint8_t)value;
205 break;
206
207 case VB2_NV_FW_TRIED:
208 SETBIT(VB2_NV_OFFS_BOOT2, VB2_NV_BOOT2_TRIED);
209 break;
210
211 case VB2_NV_FW_RESULT:
212 /* Map out of range values to unknown */
213 if (value > VB2_NV_BOOT2_RESULT_MASK)
214 value = VB2_FW_RESULT_UNKNOWN;
215
216 p[VB2_NV_OFFS_BOOT2] &= ~VB2_NV_BOOT2_RESULT_MASK;
217 p[VB2_NV_OFFS_BOOT2] |= (uint8_t)value;
218 break;
219
220 case VB2_NV_FW_PREV_TRIED:
221 SETBIT(VB2_NV_OFFS_BOOT2, VB2_NV_BOOT2_PREV_TRIED);
222 break;
223
224 case VB2_NV_FW_PREV_RESULT:
225 /* Map out of range values to unknown */
226 if (value > VB2_NV_BOOT2_RESULT_MASK)
227 value = VB2_FW_RESULT_UNKNOWN;
228
229 p[VB2_NV_OFFS_BOOT2] &= ~VB2_NV_BOOT2_PREV_RESULT_MASK;
230 p[VB2_NV_OFFS_BOOT2] |=
231 (uint8_t)(value << VB2_NV_BOOT2_PREV_RESULT_SHIFT);
232 break;
233
234 case VB2_NV_RECOVERY_REQUEST:
235 /*
236 * Map values outside the valid range to the legacy reason,
237 * since we can't determine if we're called from kernel or user
238 * mode.
239 */
240 if (value > 0xff)
241 value = VB2_RECOVERY_LEGACY;
242 p[VB2_NV_OFFS_RECOVERY] = (uint8_t)value;
243 break;
244
245 case VB2_NV_RECOVERY_SUBCODE:
246 p[VB2_NV_OFFS_RECOVERY_SUBCODE] = (uint8_t)value;
247 break;
248
249 case VB2_NV_LOCALIZATION_INDEX:
250 /* Map values outside the valid range to the default index. */
251 if (value > 0xFF)
252 value = 0;
253 p[VB2_NV_OFFS_LOCALIZATION] = (uint8_t)value;
254 break;
255
256 case VB2_NV_KERNEL_FIELD:
257 p[VB2_NV_OFFS_KERNEL] = (uint8_t)(value);
258 p[VB2_NV_OFFS_KERNEL + 1] = (uint8_t)(value >> 8);
259 p[VB2_NV_OFFS_KERNEL + 2] = (uint8_t)(value >> 16);
260 p[VB2_NV_OFFS_KERNEL + 3] = (uint8_t)(value >> 24);
261 break;
262
263 case VB2_NV_DEV_BOOT_USB:
264 SETBIT(VB2_NV_OFFS_DEV, VB2_NV_DEV_FLAG_USB);
265 break;
266
267 case VB2_NV_DEV_BOOT_LEGACY:
268 SETBIT(VB2_NV_OFFS_DEV, VB2_NV_DEV_FLAG_LEGACY);
269 break;
270
271 case VB2_NV_DEV_BOOT_SIGNED_ONLY:
272 SETBIT(VB2_NV_OFFS_DEV, VB2_NV_DEV_FLAG_SIGNED_ONLY);
273 break;
274
275 case VB2_NV_DISABLE_DEV_REQUEST:
276 SETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_DISABLE_DEV);
277 break;
278
279 case VB2_NV_OPROM_NEEDED:
280 SETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_OPROM_NEEDED);
281 break;
282
283 case VB2_NV_BACKUP_NVRAM_REQUEST:
284 SETBIT(VB2_NV_OFFS_BOOT, VB2_NV_BOOT_BACKUP_NVRAM);
285 break;
286
287 case VB2_NV_CLEAR_TPM_OWNER_REQUEST:
288 SETBIT(VB2_NV_OFFS_TPM, VB2_NV_TPM_CLEAR_OWNER_REQUEST);
289 break;
290
291 case VB2_NV_CLEAR_TPM_OWNER_DONE:
292 SETBIT(VB2_NV_OFFS_TPM, VB2_NV_TPM_CLEAR_OWNER_DONE);
293 break;
294 }
295
296 /*
297 * Note there is no default case. This causes a compiler warning if
298 * a new param is added to the enum without adding support here.
299 */
300
301 /* Need to regenerate CRC, since the value changed. */
302 vb2_nv_regen_crc(ctx);
303 }
304
305 #undef SETBIT
306