1460980 - Bugzilla SecureMail sends broken encrypted messages

Status: RESOLVED FIXED

(bugzilla.mozilla.org :: Extensions, defect)

Description

[Christian Stadelmann]

Attachment: pubkey.ascii.txt

This bug report is an answer to Dylan Hardison's Email to bugzilla.mozilla.org users on 2018-05-11 titled "Changes to Secure Bugmail on bugzilla.mozilla.org". See this blog post for more details: https://dylan.hardison.net/2018/05/11/changes-to-secure-bugmail-on-bugzilla-mozilla-org/


Uploading the public key to https://bugzilla.mozilla.org/userprefs.cgi?tab=securemail worked fine, the server does accept the key.

Decrypting the email however failed. It looks like bugzilla is doing
multiple things wrong:

1. The email claims it is encrypted against my "master" key 0x545B42FB8713DA3B, not against the subkey 0xE16B3239665BBD54. This is contrary to your blog post which lists this feature:
Fix Bug 790487: Messages will be encrypted to subkeys when possible.
        https://bugzilla.mozilla.org/show_bug.cgi?id=790487

2. The encryption is going wrong so that my Email client (GNOME Evolution) cannot decrypt it. Also, passing the file directly to GnuPG fails too with gpg2 2.2.6 and libgcrypt 1.8.2. With both tools, entering the correct password will not result in decryption. On the other hand, decrypting other emails or files works just fine and sending signed or encrypted mails works fine too.

It looks to me like the encryption routine is broken.


Attached you will find the output of

$ gpg --export --export-options export-minimal --armor
6BAC4B876A84B86A1EC87C98545B42FB8713DA3B > pubkey.ascii.txt

which is the same as

$ gpg --export --export-options export-minimal --armor
0xE16B3239665BBD54 > pubkey.ascii.txt


The script on https://dylanwh.github.io/openpgp-check/ works fine. My public key passes it and I can also decrypt the text it generates, resulting in the plaintext "Hello, world!".

Dylan sent me another email encrypted using "tct" (https://github.com/dylanwh/tocotrienol) which I can decrypt just fine. It is also encrypted using the correct subkey 0xE16B3239665BBD54.

My key might be special in the following specs:
1. It has 8096bit subkeys
2. It disallows a few algorithms

Comment 1

[Dylan Hardison [:dylan] (he/him)]

Note the *new* encryption code isn't yet on bugzilla.mozilla.org, it won't be until May 16th. 

Did you mean https://dylanwh.github.io/openpgp-check/ is not encrypting properly, or that bugzilla *currently* is not?

Comment 2

[Christian Stadelmann]

https://dylanwh.github.io/openpgp-check/ is working fine.

The bugzilla code is not working fine. It does send me broken emails as described above.

Comment 3

[Dylan Hardison [:dylan] (he/him)]

Perfect! So this will be fixed by the code on May 16th. This is excellent news

Comment 4

[Christian Stadelmann]

I can confirm that this issue has been fixed now. I just received an encrypted email. Thank you!

PS: I cannot close this bug report as "Fixed" or "Verified", can you please do that for me?