[PATCH] env: Fix warning when forcing environment without ENV_ACCESS_IGNORE_FORCE

Marek Vasut
2021-01-28T23:03:52Z

On 1/28/21 8:26 PM, Tom Rini wrote:
> On Thu, Jan 28, 2021 at 08:07:54PM +0100, Marek Vasut wrote:
>> On 1/11/21 11:27 AM, Martin Fuzzey wrote:
>>> Since commit 0f036bf4b87e ("env: Warn on force access if ENV_ACCESS_IGNORE_FORCE set")
>>> a warning message is displayed when setenv -f is used WITHOUT
>>> CONFIG_ENV_ACCESS_IGNORE_FORCE, but the variable is set anyway, resulting
>>> in lots of log pollution.
>>>
>>> env_flags_validate() returns 0 if the access is accepted, or non zero
>>> if it is refused.
>>>
>>> So the original code
>>> #ifndef CONFIG_ENV_ACCESS_IGNORE_FORCE
>>> if (flag & H_FORCE)
>>> return 0;
>>> #endif
>>>
>>> was correct, it returns 0 (accepts the modification) if forced UNLESS
>>> IGNORE_FORCE is set (in which case access checks in the following code
>>> are applied). The broken patch just added a printf to the force accepted
>>> case.
>>>
>>> To obtain the intent of the patch we need this:
>>> if (flag & H_FORCE) {
>>> #ifdef CONFIG_ENV_ACCESS_IGNORE_FORCE
>>> printf("## Error: Can't force access to \"%s\"\n", name);
>>> #else
>>> return 0;
>>> #endif
>>> }
>>>
>>> Fixes: 0f036bf4b87e ("env: Warn on force access if ENV_ACCESS_IGNORE_FORCE set")
>>>
>>> Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
>>> ---
>>> env/flags.c | 5 +++--
>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/env/flags.c b/env/flags.c
>>> index df4aed2..e3e833c 100644
>>> --- a/env/flags.c
>>> +++ b/env/flags.c
>>> @@ -563,12 +563,13 @@ int env_flags_validate(const struct env_entry *item, const char *newval,
>>> return 1;
>>> #endif
>>> -#ifndef CONFIG_ENV_ACCESS_IGNORE_FORCE
>>> if (flag & H_FORCE) {
>>> +#ifdef CONFIG_ENV_ACCESS_IGNORE_FORCE
>>> printf("## Error: Can't force access to \"%s\"\n", name);
>>> +#else
>>> return 0;
>>> - }
>>> #endif
>>
>> Based on env/Kconfig description of this option:
>>
>> config ENV_ACCESS_IGNORE_FORCE
>> bool "Block forced environment operations"
>> default n
>> help
>> If defined, don't allow the -f switch to env set override variable
>> access flags.
>>
>> I would think the code should look like this:
>>
>> #ifdef CONFIG_ENV_ACCESS_IGNORE_FORCE
>> if (flag & H_FORCE) {
>> printf("## Error: Can't force access to \"%s\"\n", name);
>> return 1;
>> }
>> #else
>> if (flag & H_FORCE)
>> return 0;
>> #endif
>
> So, prior to 0f036bf4b87e we had what you're suggesting, and that lead
> to 8a5cdf601f8d (which is the commit I was trying to think of) which
> Heinrich did not like, but was what was needed to get things to function
> again. Wouldn't what you're proposing break the use case you had in the
> first place?

No, the idea is to completely block the -f flag if
CONFIG_ENV_ACCESS_IGNORE_FORCE is set from setting anything in the
environment. That's how I understand the Kconfig entry help text.