In ESP32-H2, the ECDSA peripheral by default uses the TRNG (hardware)
generated k value but it can be overridden to software supplied k.
This can happen through by overriding the `ECDSA_SOFTWARE_SET_K` bit
in the configuration register. Even though the HAL API is not exposed
for this but still it could be achieved by direct register
programming. And for this scenario, if sufficiently random k is not
supplied by the software then it could posses a security risk.
In this change, we are unconditionally programming the efuse
`ESP_EFUSE_ECDSA_FORCE_USE_HARDWARE_K` bit during startup security
checks itself. Additionally, same is ensured in the `esp_efuse_write_key`
API as well. This always enforces the hardware k mode in the ECDSA
peripheral and ensures strongest possible security.
eFuse module has a hardware bug.
It is related to ESP32-C3, C6, S3, H2 chips:
- BLOCK9 (BLOCK_KEY5) can not be used by XTS_AES keys.
For H2 chips, the BLOCK9 (BLOCK_KEY5) can not be used by ECDSA keys.
S2 does not have such a hardware bug.
The following two functions in bootloader_support are private now:
* esp_secure_boot_verify_sbv2_signature_block()
* esp_secure_boot_verify_rsa_signature_block()
They have been moved into private header files
inside bootloader_private/
* Removed bootloader_reset_reason.h and
bootloader_common_get_reset_reason() completely.
Alternative in ROM component is available.
* made esp_efuse.h independent of target-specific rom header
