Re: [Bug-wget] Redirect containing %2B behaves differently depending on locale

[Ander Juaristi]

On 03/13/2015 11:48 PM, Adam Sampson wrote:
> Hi,
>
> I've just found a case where wget 1.16.3 responds to a 302 redirect
> differently depending on whether it's in an ASCII or UTF-8 locale.
>
> This works:
> LC_ALL=en_GB.UTF-8 wget 
> https://bitbucket.org/pypy/pypy/downloads/pypy-2.5.0-src.tar.bz2
>
> This doesn't work:
> LC_ALL=C wget https://bitbucket.org/pypy/pypy/downloads/pypy-2.5.0-src.tar.bz2
>
> I've attached logs with -d showing what's actually going on. The
> initial request gives a 302 response with a Location: that contains:
>    ....tar.bz2?Signature=up6%2BtTpSF...
>
> In the UTF-8 locale, wget correctly redirects to that location.
>
> In the ASCII locale, wget -d print a "converted: '...' -> '...'" line
> (from iri.c's do_conversion), then redirects to:
>    ....tar.bz2?Signature=up6+tTpSF...
>
> (If you try it yourself you'll get a slightly different URL, but at
> least for me it usually contains %2B somewhere.)
>
> This appears to be because do_conversion calls url_unescape on the
> input string it's given -- even though that input string is a _const_
> char * in the code that calls it (main -> retrieve_url -> url_parse ->
> remote_to_utf8 -> do_conversion). It's not immediately obvious to me
> whether that's intentional or not; at the very least, it's a surprising
> bit of behaviour.
That call to url_unescape() is necessary because iconv() needs the multibyte 
characters with no encoding. My first approach, by the way, was to remove that 
call, but that caused Test-iri-percent.px to fail, which is pretty clear.

The issue seems to be at the call to reencode_escapes(), just after remote_to_utf8() returns. The problem 
here is that %2B resolves to "+" (literal). And that character is equal to the reserved character 
"+", and reencode_escapes() treats it as a reserved characters and leaves it as-is. The same 
happens with other characters, such as "=" (%3D).

What I propose is to tag the characters that have been decoded, in 
url_unescape(), and then in reencode_escapes(), verify if they coincide with 
reserved characters as well.

What do you guys think?

--
Regards,
- AJ