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Re: Padding for PUSH_PROMISE frames

From: Ryan Hamilton <rch@google.com>
Date: Fri, 14 Feb 2014 14:11:43 -0800
Message-ID: <CAJ_4DfRpc51kxzJ=D8Q3K9ofyJobd0jU53n5pSzKdT6F7jJhjQ@mail.gmail.com>
To: Roberto Peon <grmocg@gmail.com>
Cc: Nicholas Hurley <hurley@todesschaf.org>, IETF HTTP WG <ietf-http-wg@w3.org>, Jeff Pinner <jpinner@twitter.com>
Would it make sense to consider adding an explicit padding frame instead of
adding padding *to* existing frames?


On Fri, Feb 14, 2014 at 2:06 PM, Roberto Peon <grmocg@gmail.com> wrote:

> Yup. Padding should be on any frame including a headers block, plus the
> data frame.
> -=R
>
>
> On Fri, Feb 14, 2014 at 2:01 PM, Nicholas Hurley <hurley@todesschaf.org>wrote:
>
>> I thought about adding padding to everything, but like Roberto said, it
>> gets even trickier to do correctly (i.e., without messing up the security
>> properties), and it seems a little silly to me to add padding to a frame
>> that has a constant size. Adding it to PUSH_PROMISE, though, allows hiding
>> the true size of the promised headers, and makea processing of both that
>> and HEADERS frames almost the same, conceivably simplifying  implementation.
>>  I can see an argument for it but... meh. Padding is not a security
>> feature unless it is used right. Adding it everywhere doesn't really help
>> that, and opens up stuff even wider for abuse in the myriad cases where it
>> has no real security benefit.
>>
>> -=R
>>
>>
>> On Thu, Feb 13, 2014 at 9:39 PM, Jeff Pinner <jpinner@twitter.com> wrote:
>>
>>> Should we consider adding padding to all frames?
>>>
>>> We have two bits reserved at the beginning of the length field that we
>>> could use for the two padding flags, independent of frame type.
>>>
>>>
>>> On Thu, Feb 13, 2014 at 9:26 PM, Nicholas Hurley <hurley@todesschaf.org>wrote:
>>>
>>>> All,
>>>>
>>>> Right now (as of draft-10), DATA, HEADERS, and CONTINUATION frames can
>>>> contain padding to obscure the actual size of the data being sent. I
>>>> believe it would make sense to also add the option for padding to
>>>> PUSH_PROMISE frames, as they carry (pretty much) the same type of payload
>>>> as HEADERS frames, and can benefit from padding in the same way.
>>>>
>>>> I can make a pull request if others think this is a good idea.
>>>>
>>>> Thoughts?
>>>> -Nick
>>>>
>>>
>>>
>>
>
Received on Friday, 14 February 2014 22:12:10 UTC

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