OpenSSL 3.0.0: Handle UNEXPECTED_EOF_WHILE_READING / wrap SSL_OP_IGNORE_UNEXPECTED_EOF

[tiran]

BPO	43794
Nosy	@tiran, @agronholm, @miss-islington
PRs	bpo-43794: OpenSSL 3.0.0: set OP_IGNORE_UNEXPECTED_EOF by default (GH-25309) #25309 [3.9] bpo-43794: OpenSSL 3.0.0: set OP_IGNORE_UNEXPECTED_EOF by default (GH-25309) #25313 [3.8] bpo-43794: OpenSSL 3.0.0: set OP_IGNORE_UNEXPECTED_EOF by default (GH-25309) #25314

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

Show more details

GitHub fields:

assignee = 'https://github.com/tiran'
closed_at = <Date 2021-05-02.14:07:05.788>
created_at = <Date 2021-04-09.14:13:11.374>
labels = ['expert-SSL', 'type-bug', '3.8', '3.9', '3.10']
title = 'OpenSSL 3.0.0: Handle UNEXPECTED_EOF_WHILE_READING / wrap SSL_OP_IGNORE_UNEXPECTED_EOF'
updated_at = <Date 2021-12-11.23:41:17.142>
user = 'https://github.com/tiran'

bugs.python.org fields:

activity = <Date 2021-12-11.23:41:17.142>
actor = 'alex.gronholm'
assignee = 'christian.heimes'
closed = True
closed_date = <Date 2021-05-02.14:07:05.788>
closer = 'christian.heimes'
components = ['SSL']
creation = <Date 2021-04-09.14:13:11.374>
creator = 'christian.heimes'
dependencies = []
files = []
hgrepos = []
issue_num = 43794
keywords = ['patch']
message_count = 6.0
messages = ['390632', '390640', '390642', '390643', '392699', '408350']
nosy_count = 3.0
nosy_names = ['christian.heimes', 'alex.gronholm', 'miss-islington']
pr_nums = ['25309', '25313', '25314']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue43794'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']

[tiran]

OpenSSL 3.0.0 state machine handles unexpected EOFs more strict and requires peers to properly shut down connections. The old OpenSSL 1.1.1 behavior can be get back with SSL_OP_IGNORE_UNEXPECTED_EOF.

I propose to add the option by default until Python's ssl module has better ways to perform one-way shutdown of connections.

https://www.openssl.org/docs/manmaster/man3/SSL_CTX_set_options.html

Some TLS implementations do not send the mandatory close_notify alert on shutdown. If the application tries to wait for the close_notify alert but the peer closes the connection without sending it, an error is generated. When this option is enabled the peer does not need to send the close_notify alert and a closed connection will be treated as if the close_notify alert was received.

You should only enable this option if the protocol running over TLS can detect a truncation attack itself, and that the application is checking for that truncation attack.

[tiran]

New changeset 6f37ebc by Christian Heimes in branch 'master':
bpo-43794: OpenSSL 3.0.0: set OP_IGNORE_UNEXPECTED_EOF by default (GH-25309)
6f37ebc

[miss-islington]

New changeset e18ebd9 by Miss Islington (bot) in branch '3.8':
bpo-43794: OpenSSL 3.0.0: set OP_IGNORE_UNEXPECTED_EOF by default (GH-25309)
e18ebd9