7f42d63687
When an OTA image size is larger than 50 MMU pages (approx. 3.2 MB), secure_boot_generate fails while trying to map it into memory: https://github.com/espressif/esp-idf/blob/master/components/bootloader_support/src/esp32/secure_boot.c#L72 Instead of trying to map the whole image, secure boot code should split the image into chunks and map them one by one, like it is done in esp_image_format.c: https://github.com/espressif/esp-idf/blob/master/components/bootloader_support/src/esp_image_format.c#L371 Signed-off-by: Vikram Dattu <vikram.dattu@espressif.com>
112 lines
4 KiB
C
112 lines
4 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 "esp_secure_boot.h"
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#include "uECC.h"
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#include <sys/param.h>
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static const char* TAG = "secure_boot";
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extern const uint8_t signature_verification_key_start[] asm("_binary_signature_verification_key_bin_start");
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extern const uint8_t signature_verification_key_end[] asm("_binary_signature_verification_key_bin_end");
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#define SIGNATURE_VERIFICATION_KEYLEN 64
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#define DIGEST_LEN 32
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/* Mmap source address mask */
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#define MMAP_ALIGNED_MASK 0x0000FFFF
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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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uint8_t digest[DIGEST_LEN];
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const uint8_t *data;
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const esp_secure_boot_sig_block_t *sigblock;
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ESP_LOGD(TAG, "verifying signature src_addr 0x%x length 0x%x", src_addr, length);
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bootloader_sha256_handle_t handle = bootloader_sha256_start();
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uint32_t free_page_count = bootloader_mmap_get_free_pages();
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ESP_LOGD(TAG, "free data page_count 0x%08x", free_page_count);
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int32_t data_len_remain = length;
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uint32_t data_addr = src_addr;
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while (data_len_remain > 0) {
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uint32_t offset_page = ((data_addr & MMAP_ALIGNED_MASK) != 0) ? 1 : 0;
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/* Data we could map in case we are not aligned to PAGE boundary is one page size lesser. */
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uint32_t data_len = MIN(data_len_remain, ((free_page_count - offset_page) * SPI_FLASH_MMU_PAGE_SIZE));
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data = (const uint8_t *) bootloader_mmap(data_addr, data_len);
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if(!data) {
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ESP_LOGE(TAG, "bootloader_mmap(0x%x, 0x%x) failed", data_addr, data_len);
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bootloader_sha256_finish(handle, NULL);
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return ESP_FAIL;
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}
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bootloader_sha256_data(handle, data, data_len);
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bootloader_munmap(data);
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data_addr += data_len;
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data_len_remain -= data_len;
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}
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/* Done! Get the digest */
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bootloader_sha256_finish(handle, digest);
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// Map the signature block
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sigblock = (const esp_secure_boot_sig_block_t *) bootloader_mmap(src_addr + length, sizeof(esp_secure_boot_sig_block_t));
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if(!sigblock) {
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ESP_LOGE(TAG, "bootloader_mmap(0x%x, 0x%x) failed", src_addr + length, sizeof(esp_secure_boot_sig_block_t));
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return ESP_FAIL;
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}
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// Verify the signature
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esp_err_t err = esp_secure_boot_verify_signature_block(sigblock, digest);
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// Unmap
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bootloader_munmap(sigblock);
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return err;
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}
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esp_err_t esp_secure_boot_verify_signature_block(const esp_secure_boot_sig_block_t *sig_block, const uint8_t *image_digest)
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{
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ptrdiff_t keylen;
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bool is_valid;
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keylen = signature_verification_key_end - signature_verification_key_start;
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if(keylen != SIGNATURE_VERIFICATION_KEYLEN) {
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ESP_LOGE(TAG, "Embedded public verification key has wrong length %d", keylen);
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return ESP_FAIL;
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}
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if (sig_block->version != 0) {
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ESP_LOGE(TAG, "image has invalid signature version field 0x%08x", sig_block->version);
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return ESP_FAIL;
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}
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ESP_LOGD(TAG, "Verifying secure boot signature");
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is_valid = uECC_verify(signature_verification_key_start,
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image_digest,
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DIGEST_LEN,
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sig_block->signature,
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uECC_secp256r1());
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ESP_LOGD(TAG, "Verification result %d", is_valid);
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return is_valid ? ESP_OK : ESP_ERR_IMAGE_INVALID;
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}
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