Re: [PATCH v2] crypt: Prevent asking for password multiple times if non-default crypt name is used.

[Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 12/27/2013 02:00 PM, Colin Guthrie wrote:
> If a non-default device mapper name is used for an encrypted partion is
> used, (i.e. not luks-$UUID) due to parsing of /etc/crypttab, then the
> short-circuits put in place to prevent asking the password twice do not
> work.
> 
> This would not normally be an issue as the settled job itself should be
> removed after it has run and thus cannot be run again. Sadly, due to
> the corresponding udev rule using ACTION="add|changed", and the fact
> that trying to unlock the device (whether successful or not) seems to
> trigger a changed event, it means the settled job is recreated with
> each itteration thus causing the whole loop to run again.
> 
> It is this situation that the short-circuit exits would normally come
> into play but sadly do not work when non-standard names are used.
> 
> By the time the /tmp/cryptroot-asked-$2 file is written near the end of
> the script, the value of $2 has already been lost due to the argument
> parsing code's use of 'shift'. So while on systems where the default
> name is used are protected by checking /dev/mapper/xxxx, the
> /tmp/cryptroot-asked-$2 file didn't help on systems where this was not
> used due to this bug.
> 
> So this commit shuffles things around somewhat such that:
> 
>  1. The /dev/mapper/xxxx device is checked *after* resolving $2 (which
>     contains the default name) to whatever /etc/crypttab specifies.
>  2. The cryptroot-asked-xxxx file also uses the translated name both
>     for the initial check and to flag when it's written.
> 
> As a separate fix, it might make sense to change the udev rule to only
> act on add events rather than add|change events, but I'm not sure of the
> ramifications of such a change and there may be cases where the add
> event is missed and thus the change event needs to be included.
> ---
> 
>  v2: Fix issue where getargbool was not defined due to deferred loading
>      of dracut-crypt-lib.sh
> 
>  modules.d/90crypt/cryptroot-ask.sh | 36 +++++++++++++++++++-----------------
>  1 file changed, 19 insertions(+), 17 deletions(-)
> 

Thanks! Pushed.