Import bootloader from esp-idf v3
[apeos.git] / components / bootloader_support / src / secure_boot.c
blobef9744ffc8bf57419be78f12e71c75295c5b3312
1 // Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
15 #include <string.h>
17 #include "esp_attr.h"
18 #include "esp_types.h"
19 #include "esp_log.h"
21 #include "rom/cache.h"
22 #include "rom/ets_sys.h"
23 #include "rom/secure_boot.h"
25 #include "soc/dport_reg.h"
26 #include "soc/io_mux_reg.h"
27 #include "soc/efuse_reg.h"
28 #include "soc/rtc_cntl_reg.h"
30 #include "sdkconfig.h"
32 #include "bootloader_flash.h"
33 #include "bootloader_random.h"
34 #include "esp_image_format.h"
35 #include "esp_secure_boot.h"
36 #include "esp_flash_encrypt.h"
37 #include "esp_efuse.h"
39 static const char* TAG = "secure_boot";
41 /**
42 * @function : secure_boot_generate
43 * @description: generate boot digest (aka "abstract") & iv
45 * @inputs: image_len - length of image to calculate digest for
47 static bool secure_boot_generate(uint32_t image_len){
48 esp_err_t err;
49 esp_secure_boot_iv_digest_t digest;
50 const uint32_t *image;
52 /* hardware secure boot engine only takes full blocks, so round up the
53 image length. The additional data should all be 0xFF.
55 if (image_len % sizeof(digest.iv) != 0) {
56 image_len = (image_len / sizeof(digest.iv) + 1) * sizeof(digest.iv);
58 ets_secure_boot_start();
59 ets_secure_boot_rd_iv((uint32_t *)digest.iv);
60 ets_secure_boot_hash(NULL);
61 /* iv stored in sec 0 */
62 err = bootloader_flash_erase_sector(0);
63 if (err != ESP_OK)
65 ESP_LOGE(TAG, "SPI erase failed: 0x%x", err);
66 return false;
69 /* generate digest from image contents */
70 image = bootloader_mmap(ESP_BOOTLOADER_OFFSET, image_len);
71 if (!image) {
72 ESP_LOGE(TAG, "bootloader_mmap(0x1000, 0x%x) failed", image_len);
73 return false;
75 for (int i = 0; i < image_len; i+= sizeof(digest.iv)) {
76 ets_secure_boot_hash(&image[i/sizeof(uint32_t)]);
78 bootloader_munmap(image);
80 ets_secure_boot_obtain();
81 ets_secure_boot_rd_abstract((uint32_t *)digest.digest);
82 ets_secure_boot_finish();
84 ESP_LOGD(TAG, "write iv+digest to flash");
85 err = bootloader_flash_write(FLASH_OFFS_SECURE_BOOT_IV_DIGEST, &digest,
86 sizeof(digest), esp_flash_encryption_enabled());
87 if (err != ESP_OK) {
88 ESP_LOGE(TAG, "SPI write failed: 0x%x", err);
89 return false;
91 Cache_Read_Enable(0);
92 return true;
95 /* Burn values written to the efuse write registers */
96 static inline void burn_efuses()
98 #ifdef CONFIG_SECURE_BOOT_TEST_MODE
99 ESP_LOGE(TAG, "SECURE BOOT TEST MODE. Not really burning any efuses! NOT SECURE");
100 #else
101 esp_efuse_burn_new_values();
102 #endif
105 esp_err_t esp_secure_boot_permanently_enable(void) {
106 esp_err_t err;
107 uint32_t image_len = 0;
108 if (esp_secure_boot_enabled())
110 ESP_LOGI(TAG, "bootloader secure boot is already enabled, continuing..");
111 return ESP_OK;
114 err = esp_image_verify_bootloader(&image_len);
115 if (err != ESP_OK) {
116 ESP_LOGE(TAG, "bootloader image appears invalid! error %d", err);
117 return err;
120 uint32_t dis_reg = REG_READ(EFUSE_BLK0_RDATA0_REG);
121 bool efuse_key_read_protected = dis_reg & EFUSE_RD_DIS_BLK2;
122 bool efuse_key_write_protected = dis_reg & EFUSE_WR_DIS_BLK2;
123 if (efuse_key_read_protected == false
124 && efuse_key_write_protected == false
125 && REG_READ(EFUSE_BLK2_RDATA0_REG) == 0
126 && REG_READ(EFUSE_BLK2_RDATA1_REG) == 0
127 && REG_READ(EFUSE_BLK2_RDATA2_REG) == 0
128 && REG_READ(EFUSE_BLK2_RDATA3_REG) == 0
129 && REG_READ(EFUSE_BLK2_RDATA4_REG) == 0
130 && REG_READ(EFUSE_BLK2_RDATA5_REG) == 0
131 && REG_READ(EFUSE_BLK2_RDATA6_REG) == 0
132 && REG_READ(EFUSE_BLK2_RDATA7_REG) == 0) {
133 ESP_LOGI(TAG, "Generating new secure boot key...");
134 uint32_t buf[8];
135 bootloader_fill_random(buf, sizeof(buf));
136 for (int i = 0; i < 8; i++) {
137 ESP_LOGV(TAG, "EFUSE_BLK2_WDATA%d_REG = 0x%08x", i, buf[i]);
138 REG_WRITE(EFUSE_BLK2_WDATA0_REG + 4*i, buf[i]);
140 bzero(buf, sizeof(buf));
141 burn_efuses();
142 ESP_LOGI(TAG, "Read & write protecting new key...");
143 REG_WRITE(EFUSE_BLK0_WDATA0_REG, EFUSE_WR_DIS_BLK2 | EFUSE_RD_DIS_BLK2);
144 burn_efuses();
145 efuse_key_read_protected = true;
146 efuse_key_write_protected = true;
148 } else {
149 ESP_LOGW(TAG, "Using pre-loaded secure boot key in EFUSE block 2");
152 ESP_LOGI(TAG, "Generating secure boot digest...");
153 if (false == secure_boot_generate(image_len)){
154 ESP_LOGE(TAG, "secure boot generation failed");
155 return ESP_FAIL;
157 ESP_LOGI(TAG, "Digest generation complete.");
159 #ifndef CONFIG_SECURE_BOOT_TEST_MODE
160 if (!efuse_key_read_protected) {
161 ESP_LOGE(TAG, "Pre-loaded key is not read protected. Refusing to blow secure boot efuse.");
162 return ESP_ERR_INVALID_STATE;
164 if (!efuse_key_write_protected) {
165 ESP_LOGE(TAG, "Pre-loaded key is not write protected. Refusing to blow secure boot efuse.");
166 return ESP_ERR_INVALID_STATE;
168 #endif
170 ESP_LOGI(TAG, "blowing secure boot efuse...");
171 ESP_LOGD(TAG, "before updating, EFUSE_BLK0_RDATA6 %x", REG_READ(EFUSE_BLK0_RDATA6_REG));
173 uint32_t new_wdata6 = EFUSE_RD_ABS_DONE_0;
175 #ifndef CONFIG_SECURE_BOOT_ALLOW_JTAG
176 ESP_LOGI(TAG, "Disable JTAG...");
177 new_wdata6 |= EFUSE_RD_DISABLE_JTAG;
178 #else
179 ESP_LOGW(TAG, "Not disabling JTAG - SECURITY COMPROMISED");
180 #endif
182 #ifndef CONFIG_SECURE_BOOT_ALLOW_ROM_BASIC
183 ESP_LOGI(TAG, "Disable ROM BASIC interpreter fallback...");
184 new_wdata6 |= EFUSE_RD_CONSOLE_DEBUG_DISABLE;
185 #else
186 ESP_LOGW(TAG, "Not disabling ROM BASIC fallback - SECURITY COMPROMISED");
187 #endif
189 REG_WRITE(EFUSE_BLK0_WDATA6_REG, new_wdata6);
190 burn_efuses();
191 uint32_t after = REG_READ(EFUSE_BLK0_RDATA6_REG);
192 ESP_LOGD(TAG, "after updating, EFUSE_BLK0_RDATA6 %x", after);
193 if (after & EFUSE_RD_ABS_DONE_0) {
194 ESP_LOGI(TAG, "secure boot is now enabled for bootloader image");
195 return ESP_OK;
196 } else {
197 #ifdef CONFIG_SECURE_BOOT_TEST_MODE
198 ESP_LOGE(TAG, "secure boot not enabled due to test mode");
199 #else
200 ESP_LOGE(TAG, "secure boot not enabled for bootloader image, EFUSE_RD_ABS_DONE_0 is probably write protected!");
201 #endif
202 return ESP_ERR_INVALID_STATE;