bug#10536: 23.3; Make base64-decode more fault tolerant

[Noam Postavsky]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> writes:

>> there was a missing padding character, i.e. the last quartet was
>> "xy=" rather than the proper "xy==".
>>
>> I would suggest that base64-decode should tolerate this, like with
>> the appended patch.

>>        if (c == '=')
>>      {
>> -      READ_QUADRUPLET_BYTE (-1);
>> +      /* Be tolerant against missing final padding '='.  */
>> +      READ_QUADRUPLET_BYTE (e-to);

> What do the rest of you people think?  (I think I'm slightly for
> applying the patch.  "Be liberal in what you receive" and all that.)

Makes sense to me.