Recover Firefox / Iceweasel password files from backup

Question

I recently set my Firefox (actually Iceweasel 24.3.0) master password and promptly forgot it.

Before I set the master password I made a backup of my homedir and want to recover the password files from there. If all else fails I will make a complete recovery of the firefox directory which I assume will work. But I'd rather keep my history etc.

I read Where are my Firefox passwords saved? and tried to restore only the files key3.db, signons.sqlite and signons3.txt. That prompted an error message that the Security System could not be started properly and no site could be opened. So currently I again have the locked files there.

Question is: What Files do I need to recover from my backup to reset the master password? If necessary what additional settings do I have to make for it to work?

Answer 1

Its not enough to copy the files, you also have to ensure that they have the correct permissions.

On linux it is 644 for the signons.sqlite and 600 for key3.db. signons3.txt isn't needed at all.

PS: Using a Password generation system that creates repeatably passwords from a given starting one helps prevent such situations. There is an App for Android (Master Password) that does that technically, but using a manual approach will improve the situation too.