deja-dup backup keeps asking for password: GPGError 31

[lbo]

1. Distribution: Ubuntu 11.10

2. Program Versions:
deja-dup 20.1-0ubuntu0.2
duplicity 0.6.15-0ubuntu2
gnupg 1.4.11-3ubuntu1.11.10.2
gnome-keyring 3.2.2-0ubuntu0.1

I've been using deja-dup for about one year for daily encrypted backups of my laptop to a remote file server. That seemed to work fine for a long time. Since a few days (possibly since 2013-03-15, see .gsettings), the backup procedure starts, shows the usual "Backing Up..." dialog for a while, and then prompts me for a password in the "Encryption Password Needed" dialog. The password field and checkboxes are initially empty/unset. After entering my encryption password and setting the "Remember password" checkbox, backup proceeds again for a few minutes showing the "Backing Up..." dialog, but then the "Encryption Password Needed" dialog is displayed again. On this second and all subsequent occurrences of this dialog, my password is already filled and the checkboxes are set according to my previous entries. I need to press continue.

This sequence of "Backing Up..." and "Encryption Password Needed" then keeps repeating many times until the backup process finally exits. It's not precisely clear to me whether it finishes successfully or not. There is no error message in the UI, but from the following error message related to GPG I see in the the deja-dup.log, I doubt that the backup could be successfully created:

DUPLICITY: ERROR 31 GPGError
DUPLICITY: . GPGError: GPG Failed, see log below:
DUPLICITY: . ===== Begin GnuPG log =====
DUPLICITY: . gpg: CAST5 encrypted data
DUPLICITY: . gpg: encrypted with 1 passphrase
DUPLICITY: . gpg: block_filter 0xdaebf0: read error (size=12376,a->size=12376)
DUPLICITY: . gpg: [don't know]: invalid packet (ctb=7b)
DUPLICITY: . gpg: [don't know]: invalid packet (ctb=3a)
DUPLICITY: . gpg: mdc_packet with invalid encoding
DUPLICITY: . gpg: decryption failed: invalid packet
DUPLICITY: . gpg: [don't know]: invalid packet (ctb=46)
DUPLICITY: . gpg: block_filter: pending bytes!
DUPLICITY: . ===== End GnuPG log =====
DUPLICITY: .

I have studied other bug reports related to deja-dup and GPG, bug #681002, and I'm quite sure this is _not_ a duplicate of 681002 because:

1. the message mentioned in that bug report's header line is nowhere in my logs
2. in my version of duplicity, GPG is already run with the option '--gpg-options=--no-use-agent', see deja-dup.log.
3. my version of gnome-keyring should already have the fix for 681002

Please advise on how to resolve this.

Thanks & best regards,
Lambert

[Michael Terry (mterry)]

Thanks for your bug report! I'm sorry you're having problems and that it's taken so long to get a response. If you haven't moved on yet, here's what I'd say to do:

A) I recommend upgrading to a supported version of Ubuntu. You won't receive important bug fixes if you stick with Ubuntu 11.10.

B) It looks like one of your backup files is corrupted (likely by a few known bugs in your duplicity version). It appears to be "duplicity-full-signatures.20130310T085312Z.sigtar.gpg" If you move your old backups out of the way and try again, it should work.

Since I suspect this is due to bugs fixed in later versions of duplicity, and that there's nothing we can do to fix it now, I'll mark this bug Invalid.

[lbo (l-boskamp)]

Hi Michael,

thanks for your feedback. I have upgraded to Precise a few weeks ago. Before the upgrade, I removed deja-dup/duplicity including all of their configuration. After the upgrade, I re-installed them and put a new configuration in place, which stores all backups in a different folder of my remote backup storage. Again, I've configured encrypted storage of my backups.

I've done a few successful backup runs in the meantime. So far, the problem has not come back again. Should it come back, I'll re-open this issue.

BR, Lambert