BackendException: SSL failed: [SSL: CERTIFICATE_VERIFY_FAILED]

[Joe]

duplicity 0.7.11
python 2.7.13

When trying to use duplicity with webdavs I get the following error:

BackendException: SSL failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:661)

I tried what is mentioned in "Note on Ssl Certificate Verification" (https://curl.haxx.se/docs/caextract.html) in the doc

--ssl-cacert-file /etc/duplicity/cacert.pem

and

--ssl-cacert-path /etc/duplicity

and

-ssl-no-check-certificate

and I also copied the file to

~/.duplicity/cacert.pem
~/duplicity_cacert.pem
/etc/duplicity/cacert.pem

Nothing worked, still the same message.

I found this thread

https://duplicity-talk.nongnu.narkive.com/behoUdPH/webdav-ssl-certificate-verify-failed

in the end they suggested to use lftp+webdavs instead of webdavs, this
also worked for me. Any ideas why webdavs only does not work?
If something has been deprecated it should be added to the doc.

[Joe (homerun4711)]

Same issue on current stable 0.7.18

I had a look at the source (webdavbackend.py) and the parameter
--ssl-no-check-certificate is working as expected.

The exception is thrown in _list

https://bazaar.launchpad.net/~duplicity-team/duplicity/0.7-series/view/head:/duplicity/backends/webdavbackend.py#L308

The --ssl-no-check-certificate option

https://bazaar.launchpad.net/~duplicity-team/duplicity/0.7-series/view/head:/duplicity/backends/webdavbackend.py#L190

creates a httplib.HTTPSConnection instead of a VerifiedHTTPSConnection
but the error happens anyway. Are the certificates checked anyway?

[David Smith (sidicas2)]

Had the same problem
pip install 'httplib2==0.10.3'
Resolved it.
Found this post that says it's a problem with httplib2.
https://github.com/httplib2/httplib2/issues/47