data_received called on protocol after call to pause_reading on ssl transport

[chrisb2]

BPO	45159
Nosy	@asvetlov, @1st1, @kumaraditya303

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2022-02-26.14:47:06.342>
created_at = <Date 2021-09-10.04:23:52.349>
labels = ['3.11', 'type-bug', 'expert-asyncio']
title = 'data_received called on protocol after call to pause_reading on ssl transport'
updated_at = <Date 2022-02-26.14:47:06.339>
user = 'https://bugs.python.org/chrisb2'

bugs.python.org fields:

activity = <Date 2022-02-26.14:47:06.339>
actor = 'asvetlov'
assignee = 'none'
closed = True
closed_date = <Date 2022-02-26.14:47:06.342>
closer = 'asvetlov'
components = ['asyncio']
creation = <Date 2021-09-10.04:23:52.349>
creator = 'chrisb2'
dependencies = []
files = []
hgrepos = []
issue_num = 45159
keywords = []
message_count = 2.0
messages = ['401553', '414106']
nosy_count = 4.0
nosy_names = ['asvetlov', 'yselivanov', 'kumaraditya', 'chrisb2']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45159'
versions = ['Python 3.11']

[chrisb2]

An SSL connection created with loop.create_connection may have data_received called on its protocol after pause_reading has been called on the transport.

If an application has a protocol whose data_received method calls pause_reading on the transport then there is a chance that the data_received method will be called again before the application calls resume_reading on the transport.

That existing implementation of pause_reading at:

cpython/Lib/asyncio/sslproto.py

Line 335 in 62fa613

self._ssl_protocol._transport.pause_reading()

calls pause_reading on the underlying socket transport, which is correct. However, there is a loop in the SSLProtocol's data_received method:

cpython/Lib/asyncio/sslproto.py

Line 335 in 62fa613

self._ssl_protocol._transport.pause_reading()

If the loop referenced above has more than one iteration then there is a chance that the application protocol's data_received method could call pause_reading on the transport. If that happens on any iteration of the loop other than the last iteration, then the SSLProtocol's data_received method will call the application protocol's data_received method when it should not.

Stealing uvloop's asyncio ssl implementation would resolve this bug: https://bugs.python.org/issue44011

[kumaraditya303]

Since https://bugs.python.org/issue44011 is fixed, this can be closed now.