Occasional invalid master key in WebDAVS service #243
Description
From time to time we see davs.log entries on the form:
2025-05-13 09:22:16,017 ERROR Invalid SSL master_key: b'dd7a0b7a54024bd039b166b12391719e5871532ae8ae0821920189fe5f92a557'
with the key value changing but always of length 64 hex ciphers.
They appear to come from the ssl_master_key extraction function of the webdavs SSL socket session key in mig/shared/sslsession.py and they fail because they are not of the defined expected key length (96).
We used to extract those keys from our own legacy sslsession C-extension but we switched over to the sslkeylog library instead with the move to python3, so something may have changed and need adjustment.
It may be just noise from stray scanners, but we should probably revisit the WebDAVS session tracking and make sure it generally works with the new helper and filter any such noise.