Security

[中文]

Memory Protection

Starting from ESP-IDF v6.2, on ESP32-C5, ESP32-C6, ESP32-C61, ESP32-H2, and ESP32-P4 the second stage bootloader no longer configures or locks any RISC-V PMP entries. The complete PMP configuration is now programmed and locked by the application during early startup.

A PMP entry locked by the bootloader cannot be reconfigured until the next CPU reset. Since the bootloader on a deployed device is generally never updated, entries locked by an older bootloader could conflict with the PMP layout expected by an application built with a newer ESP-IDF version, leading to boot failures or to memory protection being silently inactive.

Applications built with ESP-IDF are not affected, as they program and lock the full PMP configuration themselves during startup, before any application code runs.

Custom (non-ESP-IDF) applications launched by the ESP-IDF second stage bootloader must not assume that any PMP entries are pre-configured or locked at handoff. Previously, the bootloader configured and locked entries covering, e.g., the ROM and the peripheral address spaces; such applications must now program their own PMP configuration.

Image verification split out of bootloader_support

Image verification and secure-boot signature checking moved from bootloader_support into the new esp_image_verify component. bootloader_support no longer depends on mbedtls.

  • Components that relied on bootloader_support transitively providing mbedtls or app_update must now declare those dependencies explicitly in their PRIV_REQUIRES / REQUIRES.

  • bootloader_common_get_sha256_of_partition() is deprecated. Use esp_partition_get_sha256() instead.

  • In builds that do not include the esp_image_verify component (no OTA or signed-image features), calling esp_partition_get_sha256() or the deprecated function above fails at link time with an undefined reference to esp_image_get_metadata / bootloader_sha256_flash_contents. Add esp_image_verify (or app_update, which includes it and provides the OTA APIs) to the calling component's PRIV_REQUIRES or to the project's COMPONENTS list.

  • Builds enabling CONFIG_SECURE_SIGNED_ON_UPDATE_NO_SECURE_BOOT must include the esp_image_verify component, which provides the startup check that verifies the running app's signature. Apps using OTA get it automatically through app_update; apps that trim the component graph (e.g. MINIMAL_BUILD) must add esp_image_verify (or app_update) to a PRIV_REQUIRES list or the project COMPONENTS. Such builds fail with a #error instead of silently skipping the configured check.

  • The Kconfig option CONFIG_SECURE_SIGNED_DATA_PARTITION was renamed to CONFIG_APP_UPDATE_SECURE_SIGNED_DATA_PARTITION (old name still accepted via sdkconfig.rename).

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