Hello,
I read the code about environment variable protection and an old discussion: https://lists.denx.de/pipermail/u-boot/2021-April/446247.html but I still have a question.
In env_flags_init() we have: if (first_call) { #ifdef CONFIG_ENV_WRITEABLE_LIST flags_list = ENV_FLAGS_LIST_STATIC; #else flags_list = env_get(ENV_FLAGS_VAR); #endif first_call = 0; }
When ENV_WRITEABLE_LIST is enabled, why do we have to initialize the list with ENV_FLAGS_LIST_STATIC instead of ".flags" ? Doing so makes ".flags" being ignored.
In env_flags_lookup() there is already a fallback when a flag is not found, the static list will be checked.
Since default env is firstly loaded in env_load(), external ".flags" are rejected and don't affect the security: change_ok() rejected setting variable .flags, skipping it!
Advantage of using .flags is being able to use a <board>.env file to group all variables together without modifying the included header.
Best regards, Zixun