SSL and certificate validation¶
All SSL configuration is done per-storage.
Pinning by fingerprint¶
To pin the certificate by fingerprint:
[storage foo] type = "caldav" ... verify_fingerprint = "94:FD:7A:CB:50:75:A4:69:82:0A:F8:23:DF:07:FC:69:3E:CD:90:CA" #verify = false # Optional: Disable CA validation, useful for self-signed certs
SHA1-, SHA256- or MD5-Fingerprints can be used. They’re detected by their length.
You can use the following command for obtaining a SHA-1 fingerprint:
echo -n | openssl s_client -connect unterwaditzer.net:443 | openssl x509 -noout -fingerprint
verify_fingerprint doesn’t suffice for vdirsyncer to work with
self-signed certificates (or certificates that are not in your trust store). You
most likely need to set
verify = false as well. This disables verification
of the SSL certificate’s expiration time and the existence of it in your trust
store, all that’s verified now is the fingerprint.
However, please consider using Let’s Encrypt such that you can forget about all of that. It is easier to deploy a free certificate from them than configuring all of your clients to accept the self-signed certificate.
Custom root CAs¶
To point vdirsyncer to a custom set of root CAs:
[storage foo] type = "caldav" ... verify = "/path/to/cert.pem"
However, the actual behavior depends on how you have installed it. Many Linux
distributions patch their
python-requests package to use the system
certificate CAs. Normally these two stores are similar enough for you to not
But there are cases where certificate validation fails even though you can
access the server fine through e.g. your browser. This usually indicates that
your installation of the
requests library is somehow broken. In such cases,
it makes sense to explicitly set
verify_fingerprint as shown
Client certificates may be specified with the
auth_cert parameter. If the
key and certificate are stored in the same file, it may be a string:
[storage foo] type = "caldav" ... auth_cert = "/path/to/certificate.pem"
If the key and certificate are separate, a list may be used:
[storage foo] type = "caldav" ... auth_cert = ["/path/to/certificate.crt", "/path/to/key.key"]