SSL handshake fails

[samaklis]

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I have a MQTT (Mosquitto) server listening for websocket connections from clients and is secured via a valid 3rd party issued SSL certificate. All connections work as expected from all clients. After upgrading to iOS 13.5.1 the connections are failing with a SSL CERTIFICATE_VERIFY_FAILED error in Pythonista in ssl.py in do_handshake self.sslobj.do_handshake() (It was working fine up to version 14.*)

I can replicate the behavior in both my iPhone and iPad

When looking at the server logs I see: sslv3 alert certificate expired, which is misleading as the certificate is valid. I am not sure if this is because the ssl.py in Pythonista is an old version. (2016)

Pythonista version 3.3 (330025) default interpreter 3.6.1 iOS 13.5.1

Sample code that works outside of Pythonista without getting the SSL error:

import ssl
import socket


host = 'i_can_provide_hostname_privately'

context = ssl.create_default_context()

with socket.create_connection((host, 9001)) as sock:
    with context.wrap_socket(sock, server_hostname=host) as ssock:
        print(ssock.version())

I have tested the issue by installing a local version of openssl: OpenSSL 1.0.2f 28 Jan 2016 which is the same that Pythonista comes with and when I issue the command openssl s_client connect host:port I get the below (look at error in return code)

No client certificate CA names sent
Peer signing digest: SHA512
Server Temp Key: ECDH, P-256, 256 bits
---
SSL handshake has read 5357 bytes and written 443 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : ECDHE-RSA-AES256-GCM-SHA384
    Session-ID: 3B19973E06CB84FCBB96178FA11FE78A13AC697854FBBD51A895B39B65829C4E
    Session-ID-ctx:
    Master-Key: DDBE9EAFC7FC20E6956EB694FCF1621B495E24EAB134D5EB44BB4A22134138B638047F571DB113CCA3D86DC1C9196D8B
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    TLS session ticket lifetime hint: 7200 (seconds)
    TLS session ticket:
    0000 - 04 f6 10 db 51 72 36 ff-01 ef 3a a0 16 c8 62 02   ....Qr6...:...b.
    0010 - b1 98 95 76 50 76 e4 12-af 28 d8 4c d1 26 75 2f   ...vPv...(.L.&u/
    0020 - 7a de ed e0 0b d7 0a 9f-b1 c9 6c af f3 4a 4c 1d   z.........l..JL.
    0030 - 41 7a 23 37 73 8b 21 90-2c a6 23 f7 11 30 28 8b   Az#7s.!.,.#..0(.
    0040 - 9f fc 1f d2 f9 07 f8 e5-5d a6 00 02 9d 9f ad f1   ........].......
    0050 - e1 a6 c9 48 3a 17 25 95-98 ae 16 f5 38 e0 a0 f8   ...H:.%.....8...
    0060 - ce f1 51 59 31 57 fa 30-49 39 f1 55 b9 e7 48 b7   ..QY1W.0I9.U..H.
    0070 - ae 12 a3 fb 6c 76 52 23-d5 53 08 0b 59 01 77 b2   ....lvR#.S..Y.w.
    0080 - 31 0e 3a b5 10 b7 6b a4-b6 1f 2b b5 73 af b9 c7   1.:...k...+.s...
    0090 - 7f 56 85 15 07 33 c4 4c-d9 11 00 7b 2d b1 b3 26   .V...3.L...{-..&

    Start Time: 1591927357
    Timeout   : 300 (sec)
    Verify return code: 20 (unable to get local issuer certificate)

When I run the same command with version: OpenSSL 1.1.1f 31 Mar 2020 I get no errors (look at return code=0):

No client certificate CA names sent
Peer signing digest: SHA512
Peer signature type: RSA
Server Temp Key: ECDH, P-256, 256 bits
---
SSL handshake has read 5381 bytes and written 434 bytes
Verification: OK
---
New, TLSv1.2, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : ECDHE-RSA-AES256-GCM-SHA384
    Session-ID: 2D876927EB37E715EACF58C6AEA2EDA5EC8EE3D4067D089C2CAE256345B83A8C
    Session-ID-ctx:
    Master-Key: 2AF552551C08BF01A0B8F166510E83BFDF03439A67698DA68502BC9B84891DD099C04545B73CD2D9EC729CF47D533AF5
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    TLS session ticket lifetime hint: 7200 (seconds)
    TLS session ticket:
    0000 - 04 f6 10 db 51 72 36 ff-01 ef 3a a0 16 c8 62 02   ....Qr6...:...b.
    0010 - 15 49 44 26 0e 71 18 58-54 27 28 0c 8b bb ce 38   .ID&.q.XT'(....8
    0020 - 5c b2 f8 33 13 f8 3a 14-ee 23 c8 c5 40 fe 80 c0   \..3..:..#..@...
    0030 - 05 ea f5 5e 94 4b bb 33-54 ab 46 f1 0c e8 b0 b7   ...^.K.3T.F.....
    0040 - 52 e3 51 e1 20 d6 9f 58-c6 40 5f 11 58 e1 dd de   R.Q. ..X.@_.X...
    0050 - db 05 3c 69 74 38 3b 6e-3f 93 21 bb 1d 4e 48 4a   ..<it8;n?.!..NHJ
    0060 - cf 19 f1 fd ec ac 0b e3-93 b4 4e 12 d1 03 61 9a   ..........N...a.
    0070 - 24 d6 c8 13 19 ba cd 9c-5a 1d 0c da ab e3 c5 b2   $.......Z.......
    0080 - 2d 79 f2 91 31 29 08 32-c7 1b c5 ef 89 bf fb db   -y..1).2........
    0090 - e4 66 2b a8 bb e3 23 76-ac a1 83 bb 4a 5f 4b 6c   .f+...#v....J_Kl
    00a0 - 6d 36 e2 71 ac 68 23 4b-de 6f 5c d7 b1 8c d1 5c   m6.q.h#K.o\....\

    Start Time: 1591927401
    Timeout   : 7200 (sec)
    Verify return code: 0 (ok)
    Extended master secret: yes

I think this proves that the included ssl.py that comes with Pythonista needs to be upgraded to a later version

[andypiper]

It would be great to see this updated! 👍