Pasted passwords rejected by FastMail, but manually typed passwords accepted.

  • Hi all, strange problem but I can reliably reproduce this result.

    I use the password manager KeePassDroid to paste credentials from the Android clipboard because it’s so much easier than typing them and it eliminates the possibility of typing them incorrectly. After a lot of testing, I have discovered that pasting my FastMail password into Davdroid produces a different outcome than typing it in manually. Pasting the password always results in failure to authenticate.

    This only happens with my FastMail account and Davdroid. I can paste credentials into other apps (or even into a plain text editor to visually check clipboard contents are output correctly) and see the expected outcome.

    I can even generate a QR code of my password and use a barcode scanner app to get the password into the Android clipboard and paste from there, in case this was somehow a KeePassDroid issue, but that also fails.

    The act of pasting a password from the Android clipboard produces different results than the act of manually inputting them using the Android keyboard, and this only occurs for password entry on DAV syncing apps. It’s bizarre but I have tested this exhaustively and I see the same result consistently.

    Thinking this was a FastMail issue, I installed the ‘CardDAV-Sync’ app they recommend and see the exact same issue.

    I’m using a Nexus 4, running Android 5.1.1 build LMY48T and DAVdroid installed via the F-Droid repository.

    Is there anything that can be done to troubleshoot this further, or am I stuck with a strange clipboard/pasting bug?

  • developer

    The user name and password fields are just normal Android EditTexts. For DAVdroid, it doesn’t make a difference how they’re filled (by pasting or typing).

    There must be a difference between the credentials you enter and the ones you past. Maybe something like whitespace at the end or some special characters.

  • That sounds reasonable and that’s what I thought for my first few hours troubleshooting this. But I can consistently reproduce the same results.

    • Paste anything from clipboard into other installed apps > OK
    • Paste from clipboard into DAVdroid for ownCloud account > OK
    • Paste from clipboard into plain text editor to visually check output > OK
    • Paste URL from clipboard into DAVdroid for FastMail account > OK
    • Paste password from clipboard into DAVdroid for FastMail account > Fail
    • Manually type password into DAVdroid for FastMail account > OK

    Admittedly this is a strange result but it is literally the only remaining explanation after testing this for a very long time and substituting each possible variable to isolate the problem.

    I use very long and difficult to type passwords so I try to avoid typing them. Fortunately I don’t have to set this up very often, so I think I’ll have to call this a very strange bug and use the manual typing workaround. If anyone has any tips on how to troubleshoot this further I’d love to know why this happens.

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