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[Python-Dev] Need help to fix HTTP Header Injection vulnerability

Wes Turner wes.turner at gmail.com
Wed Apr 10 06:16:10 EDT 2019 
1. Is there a library of URL / Header injection tests e.g. for fuzzing that
we could generate additional test cases with or from?

2. Are requests.get() and requests.post() also vulnerable?

3. Despite the much-heralded UNIX pipe protocols' utility, filenames
containing newlines (the de-facto line record delimiter) are possible:
"file"$'\n'"name"

Should filenames containing newlines and control characters require a kwarg
to be non-None in order to be passed through unescaped to the HTTP request?

On Wednesday, April 10, 2019, Karthikeyan <tir.karthi at gmail.com> wrote:

> Thanks Gregory. I think it's a good tradeoff to ensure this validation
> only for URLs of http scheme.
>
> I also agree handling newline is little problematic over the years and the
> discussion over the level at which validation should occur also prolongs
> some of the patches. https://bugs.python.org/issue35906 is another
> similar case where splitlines is used but it's better to raise an error and
> the proposed fix could be used there too. Victor seemed to wrote a similar
> PR like linked one for other urllib functions only to fix similar attack in
> ftplib to reject newlines that was eventually fixed only in ftplib
>
> * https://bugs.python.org/issue30713
> * https://bugs.python.org/issue29606
>
> Search also brings multiple issues with one duplicate over another that
> makes these attacks scattered over the tracker and some edge case missing.
> Slightly off topic, the last time I reported a cookie related issue where
> the policy can be overriden by third party library I was asked to fix it in
> stdlib itself since adding fixes to libraries causes maintenance burden to
> downstream libraries to keep up upstream. With urllib being a heavily used
> module across ecosystem it's good to have a fix landing in stdlib that
> secures downstream libraries encouraging users to upgrade Python too.
>
> Regards,
> Karthikeyan S
>
>>
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