Re: [quicwg/base-drafts] Security Considerations text for a memory limit (#3004)

Kazuho Oku <notifications@github.com> Wed, 04 September 2019 03:58 UTC

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Subject: Re: [quicwg/base-drafts] Security Considerations text for a memory limit (#3004)
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kazuho commented on this pull request.



> @@ -1126,6 +1126,13 @@ HTTP_QPACK_DECODER_STREAM_ERROR (0x202):
 
 TBD.
 
+While the negotiated limit on the dynamic table size accounts for much of the
+memory that can be consumed by a QPACK implementation, data which cannot be
+immediately sent due to flow control is not affected by this limit.
+Implementations MUST limit the size of unsent data, especially on the decoder
+stream where flexibility to choose what to send is limited.  If this limit is
+exceeded, the connection MUST be terminated.

I am not sure if "MUST terminate if the limit is exceeded" is a good advice, as there could be alternative strategies. For example, an endpoint can stop reading data from the streams, as well as giving the peer new stream ID credit while the amount of unsent data on the QPACK decoder stream is above some threshold.

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