Profanity crashes when OMEMO key is misconfigured

[immae]

Expected Behavior

Buggy clients may put incorrect values in eu.siacs.conversations.axolotl signedPreKeyPublic. profanity should ignore those keys and continue working.

Current Behavior

My example was with an incorrect key of the form <signedPreKeyPublic signedPreKeyId="34980">b'BR4qa16J7e2LhVcUhjsjkosCD9HAqrKo0H3ZIYWVjnVU'</signedPreKeyPublic> (notice the b' at the beginning of the string), stored by a buggy python client (namely https://gitlab.com/ecartman/sleekxmpp-omemo-plugin/ )

profanity complained and crashed.

Possible Solution

Only workaround I found is to remove manually the incorrect keys

Steps to Reproduce (for bugs)

1. Store an incorrect omemo key for a buddy
2. Start profanity

Environment

• Give us the version and build information output generated by profanity -v

Profanity, version 0.7.1
Copyright (C) 2012 - 2019 James Booth <boothj5web@gmail.com>.
Copyright (C) 2019 Michael Vetter <jubalh@iodoru.org>.
License GPLv3+: GNU GPL version 3 or later <https://www.gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Build information:
XMPP library: libmesode
Desktop notification support: Enabled
OTR support: Enabled (libotr 4.1.1)
PGP support: Enabled (libgpgme 1.12.0)
OMEMO support: Enabled
C plugins: Enabled
Python plugins: Enabled (3.7.4)
GTK icons: Enabled

• Operating System/Distribution
  nixpkgs package on archlinux