mirror of
https://github.com/espressif/esp-idf.git
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d40c69375c
Goal is that multiple faults would be required to bypass a boot-time signature check. - Also strengthens some address range checks for safe app memory addresses - Change pre-enable logic to also check the bootloader signature before enabling SBV2 on ESP32 Add some additional checks for invalid sections: - Sections only partially in DRAM or IRAM are invalid - If a section is in D/IRAM, allow the possibility only some is in D/IRAM - Only pass sections that are entirely in the same type of RTC memory region
83 lines
3.0 KiB
C
83 lines
3.0 KiB
C
// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "sdkconfig.h"
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#include "bootloader_flash.h"
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#include "bootloader_sha.h"
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#include "esp_log.h"
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#include "esp_image_format.h"
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#include "esp32s2/rom/secure_boot.h"
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static const char* TAG = "secure_boot";
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#define DIGEST_LEN 32
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esp_err_t esp_secure_boot_verify_signature(uint32_t src_addr, uint32_t length)
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{
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ets_secure_boot_key_digests_t trusted_keys = { 0 };
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uint8_t digest[DIGEST_LEN];
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uint8_t verified_digest[DIGEST_LEN] = { 0 }; /* Note: this function doesn't do any anti-FI checks on this buffer */
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const uint8_t *data;
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ESP_LOGD(TAG, "verifying signature src_addr 0x%x length 0x%x", src_addr, length);
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if ((src_addr + length) % 4096 != 0) {
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ESP_LOGE(TAG, "addr 0x%x length 0x%x doesn't end on a sector boundary", src_addr, length);
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return ESP_ERR_INVALID_ARG;
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}
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data = bootloader_mmap(src_addr, length + sizeof(struct ets_secure_boot_sig_block));
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if (data == NULL) {
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ESP_LOGE(TAG, "bootloader_mmap(0x%x, 0x%x) failed", src_addr, length+sizeof(ets_secure_boot_signature_t));
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return ESP_FAIL;
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}
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// Calculate digest of main image
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#ifdef BOOTLOADER_BUILD
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bootloader_sha256_handle_t handle = bootloader_sha256_start();
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bootloader_sha256_data(handle, data, length);
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bootloader_sha256_finish(handle, digest);
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#else
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/* Use thread-safe esp-idf SHA function */
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esp_sha(SHA2_256, data, length, digest);
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#endif
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int r = ets_secure_boot_read_key_digests(&trusted_keys);
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if (r == ETS_OK) {
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const ets_secure_boot_signature_t *sig = (const ets_secure_boot_signature_t *)(data + length);
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// TODO: calling this function in IDF app context is unsafe
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r = ets_secure_boot_verify_signature(sig, digest, &trusted_keys, verified_digest);
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}
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bootloader_munmap(data);
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return (r == ETS_OK) ? ESP_OK : ESP_FAIL;
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}
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esp_err_t esp_secure_boot_verify_rsa_signature_block(const ets_secure_boot_signature_t *sig_block, const uint8_t *image_digest, uint8_t *verified_digest)
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{
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ets_secure_boot_key_digests_t trusted_keys;
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int r = ets_secure_boot_read_key_digests(&trusted_keys);
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if (r != 0) {
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ESP_LOGE(TAG, "No trusted key digests were found in efuse!");
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} else {
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ESP_LOGD(TAG, "Verifying with RSA-PSS...");
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// TODO: calling this function in IDF app context is unsafe
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r = ets_secure_boot_verify_signature(sig_block, image_digest, &trusted_keys, verified_digest);
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}
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return (r == 0) ? ESP_OK : ESP_ERR_IMAGE_INVALID;
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}
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