Re: [PATCH v2 2/2] dns.cgi: Fixes bug#12395 - German umlauts not correctly displayed in remarks

[Adolf Belka <adolf.belka@ipfire.org>]

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Hi Michael,

On 12/03/2024 11:02, Michael Tremer wrote:
> Thank you.
> 
> I merged this for now so that we can fix this problem quickly.
> 
> However I was wondering whether we should consider making the decode statement a part of the “cleanhtml” function.
That makes a lot of sense. It would also mean that the problem of 
umlauts etc would be fixed everywhere that cleanhtml is used rather than 
needing to fix every invocation of cleanhtml.

I will look at putting something together for that.

> 
> I am still unsure why this is happening in the first place. We should be receiving UTF-8 from the browser, and I believe that perl doesn’t natively store things in UTF-8. That is however not a problem, because it should read files the same way it wrote them and so there should not be any difference when we re-read the configuration files. Unless some parts of the code specify any kind of encoding.
We do receive UTF-8 from the browser. The problem seems to be that the 
HTML::Entities::encode_entities command doesn't work with UTF-8 but with 
ISO-8859-1 encoding. I can't find where I found this the other day when 
I was searching on this topic to understand how to overcome it.

The fix is not encoding the text from the browser remark box into UTF-8 
but decoding it from UTF-8. Once the text is in the files then it is fine.

Of course my reasoning for doing the decoding may or may not be right, 
so I am always open to alternative suggestions.

Regards,

Adolf.
> 
> -Michael
> 
>> On 11 Mar 2024, at 12:19, Adolf Belka <adolf.belka(a)ipfire.org> wrote:
>>
>> - If Freifunk München e.V. is entered as a remark it gets converted to
>>    Freifunk München e.V.
>> - This is because cleanhtml is used on the UTF-8 remark text before saving it to the file
>>    and the HTML::Entities::encode_entities command that is run on that remark text does
>>    not work with UTF-8 text.
>> - If the UTF-8 text in the remark is decoded before running through the cleanhtml command
>>    then the characters with diacritical marks are correctly shown.
>> - Have tested out the fix on a remark with a range of different characters with
>>    diacritical marks and all of the ones tested were displayed correctly with the fix while
>>    in the original form they were mangled.
>>
>> Fixes: Bug#12395
>> Tested-by: Adolf Belka <adolf.belka(a)ipfire.org>
>> Signed-off-by: Adolf Belka <adolf.belka(a)ipfire.org>
>> ---
>> html/cgi-bin/dns.cgi | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/html/cgi-bin/dns.cgi b/html/cgi-bin/dns.cgi
>> index 0a34d3fd6..eb6f908d5 100644
>> --- a/html/cgi-bin/dns.cgi
>> +++ b/html/cgi-bin/dns.cgi
>> @@ -142,6 +142,13 @@ if (($cgiparams{'SERVERS'} eq $Lang::tr{'save'}) || ($cgiparams{'SERVERS'} eq $L
>> # Go further if there was no error.
>> if ( ! $errormessage) {
>> # Check if a remark has been entered.
>> +
>> + # decode the UTF-8 text so that characters with diacritical marks such as
>> + # umlauts are treated correctly by the following cleanhtml command
>> + $cgiparams{'REMARK'} = decode("UTF-8", $cgiparams{'REMARK'});
>> +
>> + # run the REMARK text through cleanhtml to ensure all unsafe html characters
>> + # are correctly encoded to their html entities
>> $cgiparams{'REMARK'} = &Header::cleanhtml($cgiparams{'REMARK'});
>>
>> my %dns_servers = ();
>> -- 
>> 2.44.0
>>
> 

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