Additionally, always enable the partition MD5 check if flash encryption is on in
Release mode. This ensures the partition table ciphertext has not been modified
(CVE-2021-27926).
The exception is pre-V3.1 ESP-IDF bootloaders and partition tables, which
don't have support for the MD5 entry.
As this mode uses the public keys attached to the existing app's signatures to
verify the next app, checking that a signature block is found on boot prevents
the possibility of deploying a non-updatable device from the factory.
Sometimes the flash size read from bootloader is not correct. This may
forbid SPI Flash driver from reading the the area larger than the size
in bootloader header.
When the new config option is enabled, the latest configured
ESPTOOLPY_FLAHSIZE in the app header will be used to override the value
read from bootloader header.
Allows booting in QIO/QOUT mode or with PSRAM on ESP32-PICO-V3 and
ESP32-PICO-V3-O2 without any config changes.
Custom WP pins (needed for fully custom circuit boards) should still be compatible.
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
This saves time when waking up from deep sleep, but potentially decreases
the security of the system. If the application able to modify itself
(especially areas that are loaded into RAM) in flash while running
without crashing or is modifies the cached bits of information about
what was last booted from the bootloader, this could cause security
issues if the user does a "deep sleep reset" since the full validation
is skipped.
Signed-off-by: Tim Nordell <tim.nordell@nimbelink.com>
We fixed some flash bugs in bootloader, but for the users used the old
vrsion bootloader, they can not fix these bugs via OTA, the solution is
add these updates in app startup.
These updates include:
1. SPI flash gpio matrix and drive strength configuration
2. SPI flash clock configuration
3. SPI flash read dummy configuration
4. SPI flash cs timing configuration
5. Update flash id of g_rom_flashchip
This MR improves existing flash encryption document to provide simplified steps
Adds two new modes for user: Development & Release
Adds a simple example
Supports encrypted write through make command
