change(secure_boot): mark ECDSA based Secure Boot V2 as insecure on affected SoCs

ECDSA based Secure Boot V2 is not functional for certain input vectors on
ESP32-C5/C61/H2/P4 and on the preview targets ESP32-H4/H21. RSA based Secure
Boot V2 is the recommended scheme where the SoC supports it. This issue will be
fixed in a future hardware ECO revision; more details will be shared through the
hardware errata document.

A new hidden Kconfig option SECURE_BOOT_V2_ECDSA_INSECURE marks the affected
mass-production SoCs (ESP32-C5/C61/H2/P4). On these SoCs, when hardware Secure
Boot V2 is enabled, the ECDSA (V2) signing scheme is no longer offered by
default; it must be turned on explicitly via SECURE_BOOT_V2_FORCE_ENABLE_ECDSA
under "Allow potentially insecure options" (CONFIG_SECURE_BOOT_INSECURE). App
signing without hardware Secure Boot is not affected. Note that ESP32-C61 has no
RSA based Secure Boot V2, so it has no Secure Boot scheme enabled by default.

The preview targets ESP32-H4 and ESP32-H21 mark ECDSA Secure Boot V2 as not
supported in their SoC capabilities instead of using the option above. As
ESP32-H4 has no other Secure Boot V2 scheme, Secure Boot is disabled entirely on
it; ESP32-H21 retains RSA based Secure Boot V2.

The security documentation keeps the ECDSA Secure Boot V2 content visible and
adds a warning describing the limitation (including that ECDSA Secure Boot V2 on
ESP32-C61 is not recommended for production). CI apps that exercise ECDSA Secure
Boot V2 on the affected SoCs set CONFIG_SECURE_BOOT_V2_FORCE_ENABLE_ECDSA
accordingly.
This commit is contained in:
Aditya Patwardhan
2026-05-27 12:59:03 +05:30
parent 0664dc6ab7
commit ef0b3dd4f9
4 changed files with 56 additions and 0 deletions

View File

@@ -1,6 +1,9 @@
CONFIG_IDF_TARGET="esp32h2"
CONFIG_IDF_TARGET_ESP32H2=y
# ECDSA Secure Boot V2 is gated behind the insecure option on the affected SoCs
CONFIG_SECURE_BOOT_INSECURE=y
CONFIG_SECURE_BOOT_V2_FORCE_ENABLE_ECDSA=y
CONFIG_SECURE_BOOT_V2_ECDSA_ENABLED=y
CONFIG_SECURE_SIGNED_APPS_ECDSA_V2_SCHEME=y
CONFIG_SECURE_BOOT_ECDSA_KEY_LEN_256_BITS=y