Description

tiran

opened on Sep 14, 2018

Issue body actions

BPO	34670
Nosy	@tiran, @benjaminp, @ned-deily, @njsmith, @xnox, @miss-islington
PRs	bpo-34670: Add TLS 1.3 post handshake auth #9460 [3.7] bpo-34670: Add TLS 1.3 post handshake auth (GH-9460) #9505 [3.6] bpo-34670: Add TLS 1.3 post handshake auth (GH-9460) #9507

^{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 = 'https://github.com/tiran'
closed_at = <Date 2021-04-19.19:53:59.522>
created_at = <Date 2018-09-14.00:16:08.840>
labels = ['expert-SSL', '3.8', 'type-bug', '3.7']
title = 'Add set_post_handshake_auth for TLS 1.3'
updated_at = <Date 2021-04-19.19:53:59.522>
user = 'https://github.com/tiran'

bugs.python.org fields:

activity = <Date 2021-04-19.19:53:59.522>
actor = 'christian.heimes'
assignee = 'christian.heimes'
closed = True
closed_date = <Date 2021-04-19.19:53:59.522>
closer = 'christian.heimes'
components = ['SSL']
creation = <Date 2018-09-14.00:16:08.840>
creator = 'christian.heimes'
dependencies = []
files = []
hgrepos = []
issue_num = 34670
keywords = ['patch']
message_count = 8.0
messages = ['325314', '325973', '326138', '326141', '326142', '326458', '327932', '391394']
nosy_count = 6.0
nosy_names = ['christian.heimes', 'benjamin.peterson', 'ned.deily', 'njs', 'xnox', 'miss-islington']
pr_nums = ['9460', '9505', '9507']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue34670'
versions = ['Python 2.7', 'Python 3.6', 'Python 3.7', 'Python 3.8']

Activity

1. tiran commented on Sep 14, 2018

   

   tiran

   on Sep 14, 2018

   MemberAuthor

   More actions

   TLS 1.3 removed renegotiation in favor of rekeying and post handshake authentication (PHA). With PHA, a server can request a client certificate from a client at some point after the handshake. The feature is commonly used by HTTP server for conditional and path specific TLS client auth. For example a server can decide to require a cert based on HTTP method and/or path. A client must announce support for PHA during the handshake

   Apache mod_ssl uses PHA, https://github.com/apache/httpd/blob/trunk/modules/ssl/ssl_engine_kernel.c#L1207

   As of OpenSSL ticket openssl/openssl#6933, TLS 1.3 clients no longer send the PHA TLS extension by default. Nikos and I requested the change, because PHA breaks some assumptions of TLS 1.2 clients. For on-demand auth, PHA extension must be enabled with SSL_CTX_set_post_handshake_auth(), https://www.openssl.org/docs/manmaster/man3/SSL_CTX_set_post_handshake_auth.html .

   I propose to add a property on SSLContext to enable PHA and backport the change to Python 2.7, 3.6 and 3.7.

   In order to test the feature, I'd also have to add some flags and a function for the server side: (SSL_VERIFY_CLIENT_ONCE, SSL_VERIFY_POST_HANDSHAKE, SSL_verify_client_post_handshake()).
2. tiran

   added

   3.7 (EOL)end of lifeend of life

   3.8 (EOL)end of lifeend of life

   on Sep 14, 2018
3. tiran

   self-assigned this

   on Sep 14, 2018
4. tiran

   added

   topic-SSL

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Sep 14, 2018
5. tiran commented on Sep 21, 2018

   

   tiran

   on Sep 21, 2018

   MemberAuthor

   More actions

   Please note that SSL_verify_client_post_handshake() doesn't perform any IO by itself.

   A typical scenario for HTTP looks like this (actual flow may vary):

   • client
     • send HTTP GET /path
   • server
     • recv
     • verify_client_post_handshake
     • send HTTP Connection Upgrade (emits CertRequest message)
   • client
     • recv
     • send upgrade confirmation (emits Certificate, CertificateVerify, Finish message)
   • server
     • recv
     • verify certificate
     • send payload or error (may emit TLS alert for unknown, invalid, or missing cert)
   • client
     • recv (receive TLS alert or server response)
6. miss-islington commented on Sep 23, 2018

   

   miss-islington

   on Sep 23, 2018

   Contributor

   More actions

   New changeset 9fb051f by Miss Islington (bot) (Christian Heimes) in branch 'master':
   bpo-34670: Add TLS 1.3 post handshake auth (GH-9460)
   9fb051f
7. miss-islington commented on Sep 23, 2018

   

   miss-islington

   on Sep 23, 2018

   Contributor

   More actions

   New changeset 2756ef3 by Miss Islington (bot) (Christian Heimes) in branch '3.7':
   [3.7] bpo-34670: Add TLS 1.3 post handshake auth (GH-9460) (GH-9505)
   2756ef3
8. miss-islington commented on Sep 23, 2018

   

   miss-islington

   on Sep 23, 2018

   Contributor

   More actions

   New changeset 94812f7 by Miss Islington (bot) (Christian Heimes) in branch '3.6':
   [3.6] bpo-34670: Add TLS 1.3 post handshake auth (GH-9460) (GH-9507)
   94812f7
9. xnox commented on Sep 26, 2018

   

   xnoxmannequin

   on Sep 26, 2018

   Mannequin

   More actions

   Will this be backported to the 2.7 branch as well? Pretty please =)
10. njsmith commented on Oct 18, 2018

    

    njsmith

    on Oct 18, 2018

    Contributor

    More actions

    FYI Christian, your "typical scenario for HTTP" doesn't make sense to me... you can't send HTTP Connection Upgrade in the middle of a regular request/response cycle. I feel like the typical scenario ought to be more like:

    • client
      • send HTTP GET /path
    • server
      • recv
      • verify_client_post_handshake (maybe... via calling SSL_do_handshake again?)
    • client
      • recv
      • send upgrade confirmation (emits Certificate, CertificateVerify, Finish message)
    • server
      • recv
      • verify certificate
      • send either the requested response, or a 401 Unauthorized depending

    But I don't really understand the underlying design here, either at the TLS 1.3 level or the openssl level, and haven't found very useful docs yet, so I could be wrong.
11. tiran commented on Apr 19, 2021

    

    tiran

    on Apr 19, 2021

    MemberAuthor

    More actions

    I don't think is anything left to do here. PHA has been supported for a while and I haven't seen any problems.
12. tiran

    closed this as completedon Apr 19, 2021
13. ezio-melotti

    transferred this issue fromon Apr 10, 2022

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