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
