[PATCH] env: mmc: Correct partition comparison in mmc_offset_try_partition

[Jaehoon Chung]

Hi,

On 11/11/20 7:25 PM, 김호연지기 wrote:
> On Wed, Nov 11, 2020 at 7:07 PM Jorge Ramirez-Ortiz, Gmail
> <jorge.ramirez.ortiz at gmail.com> wrote:
>>
>> On 11/11/20, Jaehoon Chung wrote:
>>> On 11/10/20 11:28 PM, Hoyeonjiki Kim wrote:
>>>> The function mmc_offset_try_partition searches MMC partition to save the
>>>> environment data by name.  However, it only compares the first word-size
>>>> bytes (size of 'const char *'), which may make the function to find
>>>> unintended partition.
>>>>
>>>> Correct the function not to partially compare the partition name with
>>>> config "u-boot,,mmc-env-partition".
>>>>
>>>> Signed-off-by: Hoyeonjiki Kim <jigi.kim at gmail.com>
>>>> ---
>>>>  env/mmc.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/env/mmc.c b/env/mmc.c
>>>> index 4e67180b23..505f7aa2b8 100644
>>>> --- a/env/mmc.c
>>>> +++ b/env/mmc.c
>>>> @@ -42,7 +42,7 @@ static inline int mmc_offset_try_partition(const char *str, int copy, s64 *val)
>>>>             if (ret < 0)
>>>>                     return ret;
>>>>
>>>> -           if (!strncmp((const char *)info.name, str, sizeof(str)))
>>>> +           if (!strcmp((const char *)info.name, str))
>>>
>>> Using "strlen(str)" is better than changing to strcmp.
>>>
>>> strncmp(..., ..., strlen(str))
>>
>> absolutely.
>> maybe also modify the commit like to indicate a fix to the current bug?
> 
> Thanks for the feedback for both.
> 
> However, when we do so, isn't there still the possibility for the
> function searching incorrect partition if,
> 1) "str" is shorter than "info.name", and
> 2) the first "strlen(str)" letters of "info.name" is same with those of "str"?

Make sense. You're right. :)

There are two approach. One is that choose one of those length what is longer.
Other is your approach. I don't have any objection to fix whatever.

Just resend your patch with Jorge's comment, plz. 


Best Regards,
Jaehoon Chung

> 
> This commit is for fixing the current bug, but also I wanna make sure
> that partition name matches fully.
> 
> Let me know your opinion.
> 
> Best Regards,
> Hoeyonjiki Kim
> 
>>
>>>
>>>
>>> Best Regards,
>>> Jaehoon Chung
>>>
>>>>                     break;
>>>>     }
>>>>
>>>>
>>>
>