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feat/secure_boot_v2: Adding secure boot v2 support for ESP32-ECO3

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This commit is contained in:
Supreet Deshpande
2020-02-25 01:21:41 +05:30
parent c65b67115a
commit a9ccc5e5c8
34 changed files with 950 additions and 185 deletions
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components/bootloader_support/src/idf/bootloader_sha.c
+1
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@@ -12,6 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
#include "bootloader_sha.h"
#include "bootloader_flash.h"
#include <stdbool.h>
#include <string.h>
#include <assert.h>
components/bootloader_support/src/idf/secure_boot_signatures.c
+153 -14
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@@ -15,42 +15,50 @@
#include "bootloader_flash.h"
#include "bootloader_sha.h"
#include "bootloader_utility.h"
#include "esp_log.h"
#include "esp_image_format.h"
#include "esp_secure_boot.h"
#include "mbedtls/sha256.h"
#include "mbedtls/x509.h"
#include "mbedtls/md.h"
#include "mbedtls/platform.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include <string.h>
#include <sys/param.h>
static const char *TAG = "secure_boot";
#define DIGEST_LEN 32
#ifdef CONFIG_SECURE_SIGNED_APPS_ECDSA_SCHEME
static const char *TAG = "secure_boot_v1";
extern const uint8_t signature_verification_key_start[] asm("_binary_signature_verification_key_bin_start");
extern const uint8_t signature_verification_key_end[] asm("_binary_signature_verification_key_bin_end");
#define SIGNATURE_VERIFICATION_KEYLEN 64
#define DIGEST_LEN 32
esp_err_t esp_secure_boot_verify_signature(uint32_t src_addr, uint32_t length)
{
uint8_t digest[DIGEST_LEN];
const uint8_t *data;
const esp_secure_boot_sig_block_t *sigblock;
ESP_LOGD(TAG, "verifying signature src_addr 0x%x length 0x%x", src_addr, length);
data = bootloader_mmap(src_addr, length + sizeof(esp_secure_boot_sig_block_t));
if (data == NULL) {
ESP_LOGE(TAG, "bootloader_mmap(0x%x, 0x%x) failed", src_addr, length + sizeof(esp_secure_boot_sig_block_t));
return ESP_FAIL;
esp_err_t err = bootloader_sha256_flash_contents(src_addr, length, digest);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Digest calculation failed 0x%x, 0x%x", src_addr, length);
return err;
}
// Calculate digest of main image
mbedtls_sha256_ret(data, length, digest, 0);
// Map the signature block and verify the signature
sigblock = (const esp_secure_boot_sig_block_t *)(data + length);
esp_err_t err = esp_secure_boot_verify_signature_block(sigblock, digest);
bootloader_munmap(data);
sigblock = (const esp_secure_boot_sig_block_t *)bootloader_mmap(src_addr + length, sizeof(esp_secure_boot_sig_block_t));
if (sigblock == NULL) {
ESP_LOGE(TAG, "bootloader_mmap(0x%x, 0x%x) failed", src_addr + length, sizeof(esp_secure_boot_sig_block_t));
return ESP_FAIL;
}
err = esp_secure_boot_verify_signature_block(sigblock, digest);
bootloader_munmap(sigblock);
return err;
}
@@ -123,3 +131,134 @@ cleanup:
return ret == 0 ? ESP_OK : ESP_ERR_IMAGE_INVALID;
#endif // CONFIG_MBEDTLS_ECDSA_C && CONFIG_MBEDTLS_ECP_DP_SECP256R1_ENABLED
}
#elif CONFIG_SECURE_SIGNED_APPS_RSA_SCHEME
static const char *TAG = "secure_boot_v2";
#define ALIGN_UP(num, align) (((num) + ((align) - 1)) & ~((align) - 1))
#define RSA_KEY_SIZE 384 /* RSA 3072 Bits */
esp_err_t esp_secure_boot_verify_signature(uint32_t src_addr, uint32_t length)
{
uint8_t digest[DIGEST_LEN] = {0};
/* Rounding off length to the upper 4k boundary */
int padded_length = ALIGN_UP(length, FLASH_SECTOR_SIZE);
ESP_LOGD(TAG, "verifying signature src_addr 0x%x length 0x%x", src_addr, length);
esp_err_t err = bootloader_sha256_flash_contents(src_addr, padded_length, digest);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Digest calculation failed 0x%x, 0x%x", src_addr, padded_length);
return err;
}
const ets_secure_boot_signature_t *sig_block = bootloader_mmap(src_addr + padded_length, sizeof(ets_secure_boot_signature_t));
if (sig_block == NULL) {
ESP_LOGE(TAG, "Failed to mmap data at offset 0x%x", src_addr + padded_length);
return ESP_FAIL;
}
err = esp_secure_boot_verify_signature_block(sig_block, digest);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Secure Boot V2 verification failed.");
}
bootloader_munmap(sig_block);
return err;
}
esp_err_t esp_secure_boot_verify_signature_block(const ets_secure_boot_signature_t *sig_block, const uint8_t *image_digest)
{
uint8_t i = 0, efuse_trusted_digest[DIGEST_LEN] = {0}, sig_block_trusted_digest[DIGEST_LEN] = {0};
memcpy(efuse_trusted_digest, (uint8_t *) EFUSE_BLK2_RDATA0_REG, sizeof(efuse_trusted_digest));
/* Generating the SHA of the public key components in the signature block */
bootloader_sha256_handle_t sig_block_sha;
sig_block_sha = bootloader_sha256_start();
bootloader_sha256_data(sig_block_sha, &sig_block->block[0].key, sizeof(sig_block->block[0].key));
bootloader_sha256_finish(sig_block_sha, (unsigned char *)sig_block_trusted_digest);
if (memcmp(efuse_trusted_digest, sig_block_trusted_digest, DIGEST_LEN) != 0) {
if (esp_secure_boot_enabled()) {
ESP_LOGE(TAG, "Public key digest in eFuse BLK2 and the signature block don't match.");
return ESP_FAIL;
} else {
ESP_LOGW(TAG, "Public key digest in eFuse BLK2 and the signature block don't match.");
}
}
ESP_LOGI(TAG, "Verifying with RSA-PSS...");
int ret = 0;
mbedtls_rsa_context pk;
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
unsigned char *sig_be = calloc(1, RSA_KEY_SIZE);
unsigned char *buf = calloc(1, RSA_KEY_SIZE);
if (sig_be == NULL || buf == NULL) {
return ESP_ERR_NO_MEM;
}
mbedtls_entropy_init(&entropy);
ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy, NULL, 0);
if (ret != 0) {
ESP_LOGE(TAG, "mbedtls_ctr_drbg_seed returned -0x%04x\n", ret);
goto exit;
}
for (i = 0; i < SECURE_BOOT_NUM_BLOCKS; i++) {
const mbedtls_mpi N = { .s = 1,
.n = sizeof(sig_block->block[i].key.n)/sizeof(mbedtls_mpi_uint),
.p = (void *)sig_block->block[i].key.n,
};
const mbedtls_mpi e = { .s = 1,
.n = sizeof(sig_block->block[i].key.e)/sizeof(mbedtls_mpi_uint), // 1
.p = (void *)&sig_block->block[i].key.e,
};
mbedtls_rsa_init(&pk, MBEDTLS_RSA_PKCS_V21, MBEDTLS_MD_SHA256);
ret = mbedtls_rsa_import(&pk, &N, NULL, NULL, NULL, &e);
if (ret != 0) {
ESP_LOGE(TAG, "Failed mbedtls_rsa_import, err: %d", ret);
goto exit;
}
ret = mbedtls_rsa_complete(&pk);
if (ret != 0) {
ESP_LOGE(TAG, "Failed mbedtls_rsa_complete, err: %d", ret);
goto exit;
}
ret = mbedtls_rsa_check_pubkey(&pk);
if (ret != 0) {
ESP_LOGI(TAG, "Key is not an RSA key -%0x", -ret);
goto exit;
}
/* Signature needs to be byte swapped into BE representation */
for (int j = 0; j < RSA_KEY_SIZE; j++) {
sig_be[RSA_KEY_SIZE- j - 1] = sig_block->block[i].signature[j];
}
ret = mbedtls_rsa_public( &pk, sig_be, buf);
if (ret != 0) {
ESP_LOGE(TAG, "mbedtls_rsa_public failed, err: %d", ret);
goto exit;
}
ret = mbedtls_rsa_rsassa_pss_verify( &pk, mbedtls_ctr_drbg_random, &ctr_drbg, MBEDTLS_RSA_PUBLIC, MBEDTLS_MD_SHA256, 32,
sig_block->block[i].image_digest, sig_be);
if (ret != 0) {
ESP_LOGE(TAG, "Failed mbedtls_rsa_rsassa_pss_verify, err: %d", ret);
} else {
ESP_LOGI(TAG, "Signature verified successfully!");
}
exit:
mbedtls_rsa_free(&pk);
if (ret == 0) {
break;
}
}
free(sig_be);
free(buf);
return (!ret) ? ESP_OK : ESP_ERR_IMAGE_INVALID;
}
#endif