yt-dl.org is sending an expired intermediate cert, causing validation by youtube-dl.exe (python 3.4.4) to fail

[bughit]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.05.29
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-U', '--verbose']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2020.05.29
[debug] Python version 3.4.4 (CPython) - Windows-7-6.1.7601-SP1
[debug] exe versions: ffmpeg 4.2.1, ffprobe 4.2.1
[debug] Proxy map: {}
Traceback (most recent call last):
  File "C:\Python\Python34\lib\urllib\request.py", line 1183, in do_open
  File "C:\Python\Python34\lib\http\client.py", line 1137, in request
  File "C:\Python\Python34\lib\http\client.py", line 1182, in _send_request
  File "C:\Python\Python34\lib\http\client.py", line 1133, in endheaders
  File "C:\Python\Python34\lib\http\client.py", line 963, in _send_output
  File "C:\Python\Python34\lib\http\client.py", line 898, in send
  File "C:\Python\Python34\lib\http\client.py", line 1287, in connect
  File "C:\Python\Python34\lib\ssl.py", line 362, in wrap_socket
  File "C:\Python\Python34\lib\ssl.py", line 580, in __init__
  File "C:\Python\Python34\lib\ssl.py", line 807, in do_handshake
ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpxtvjzx45\build\youtube_dl\update.py", line 46, in update_self
  File "C:\Python\Python34\lib\urllib\request.py", line 464, in open
  File "C:\Python\Python34\lib\urllib\request.py", line 482, in _open
  File "C:\Python\Python34\lib\urllib\request.py", line 442, in _call_chain
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpxtvjzx45\build\youtube_dl\utils.py", line 2736, in https_open
  File "C:\Python\Python34\lib\urllib\request.py", line 1185, in do_open
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600)>

ERROR: can't find the current version. Please try again later.

Description

yt-dl.org is sending the expired intermediate cert (the last one in the below openssl output, "COMODO RSA Certification Authority"), which is what's causing validation to fail in python. Browsers are evidently smart enough to ignore it, and build an alternate chain, but the python client is not.

 echo q | openssl s_client -connect yt-dl.org:443 -CApath /usr/lib/ssl/certs -showcerts
CONNECTED(00000003)
depth=2 C = GB, ST = Greater Manchester, L = Salford, O = COMODO CA Limited, CN = COMODO RSA Certification Authority
verify return:1
depth=1 C = GB, ST = Greater Manchester, L = Salford, O = COMODO CA Limited, CN = COMODO RSA Domain Validation Secure Server CA
verify return:1
depth=0 OU = Domain Control Validated, OU = PositiveSSL, CN = yt-dl.org
verify return:1
---
Certificate chain
 0 s:OU = Domain Control Validated, OU = PositiveSSL, CN = yt-dl.org
   i:C = GB, ST = Greater Manchester, L = Salford, O = COMODO CA Limited, CN = COMODO RSA Domain Validation Secure Server CA
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
 1 s:C = GB, ST = Greater Manchester, L = Salford, O = COMODO CA Limited, CN = COMODO RSA Domain Validation Secure Server CA
   i:C = GB, ST = Greater Manchester, L = Salford, O = COMODO CA Limited, CN = COMODO RSA Certification Authority
-----BEGIN CERTIFICATE-----
MIIGCDCCA/CgAwIBAgIQKy5u6tl1NmwUim7bo3yMBzANBgkqhkiG9w0BAQwFADCB
hTELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4G
A1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxKzApBgNV
BAMTIkNPTU9ETyBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkwHhcNMTQwMjEy
MDAwMDAwWhcNMjkwMjExMjM1OTU5WjCBkDELMAkGA1UEBhMCR0IxGzAZBgNVBAgT
EkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR
Q09NT0RPIENBIExpbWl0ZWQxNjA0BgNVBAMTLUNPTU9ETyBSU0EgRG9tYWluIFZh
bGlkYXRpb24gU2VjdXJlIFNlcnZlciBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEP
ADCCAQoCggEBAI7CAhnhoFmk6zg1jSz9AdDTScBkxwtiBUUWOqigwAwCfx3M28Sh
bXcDow+G+eMGnD4LgYqbSRutA776S9uMIO3Vzl5ljj4Nr0zCsLdFXlIvNN5IJGS0
Qa4Al/e+Z96e0HqnU4A7fK31llVvl0cKfIWLIpeNs4TgllfQcBhglo/uLQeTnaG6
ytHNe+nEKpooIZFNb5JPJaXyejXdJtxGpdCsWTWM/06RQ1A/WZMebFEh7lgUq/51
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e+FE6kKVxF0NAVBGFfKBiVlsit2M8RKhjTpCipj4SzR7JzsItG8kO3KdY3RYPBps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-----END CERTIFICATE-----
 2 s:C = GB, ST = Greater Manchester, L = Salford, O = COMODO CA Limited, CN = COMODO RSA Certification Authority
   i:C = SE, O = AddTrust AB, OU = AddTrust External TTP Network, CN = AddTrust External CA Root
-----BEGIN CERTIFICATE-----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Jw5dhHk3QBN39bSsHNA7qxcS1u80GH4r6XnTq1dFDK8o+tDb5VCViLvfhVdpfZLY
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B5a6SE2Q8pTIqXOi6wZ7I53eovNNVZ96YUWYGGjHXkBrI/V5eu+MtWuLt29G9Hvx
PUsE2JOAWVrgQSQdso8VYFhH2+9uRv0V9dlfmrPb2LjkQLPNlzmuhbsdjrzch5vR
pu/xO28QOG8=
-----END CERTIFICATE-----

the solution is described here:
https://www.agwa.name/blog/post/fixing_the_addtrust_root_expiration

you have to stop sending the expired intermediate cert because your own python client can't handle it

Fortunately, modern clients with well-written certificate validators (this includes all mainstream web browsers) won't have a problem with the expiration. Since they trust the USERTrust RSA Certification Authority root, they will build a chain to that root and ignore the fact that the server sent an expired intermediate certificate.

Other clients, notably anything using OpenSSL 1.0.x or GnuTLS, will have a problem. Even if these clients trust the USERTrust RSA Certification Authority root, and could build a chain to it if they wanted, they'll end up building a chain to AddTrust External CA Root instead, causing the certificate validation to fail with an expired certificate error.

Fixing this problem as a server operator
Basically, you need to remove the intermediate certificate issued by AddTrust External CA Root from your certificate chain.

[dstftw]

Updates without any issue for me:

> youtube-dl.exe -U
Updating to version 2020.05.29 ...
Waiting for file handle to be closed ...
Updated youtube-dl to version 2020.05.29.

In any case I don't manage certificates for yt-dl.org.
/cc @phihag.

[PierreKircher]

can you update python to say at least 3.7 and see if that persists ? 3.7 had some major ssl changes

[bughit]

The windows exe bundles python 3.4.4, so whereas it's possible that a newer python can work around this, the proper solution is to stop serving the expired cert.

[FoxMcloud5655]

Almost made a new issue with this myself, but saw this one here. Having the same issue; if additional output is needed, I can provide.

[krisu5]

Same here. I'm not using Python but everytime I tried to update exe, it just displays error message.

[dstftw]

Bump.
/cc @phihag.