Re: sorting uniquely by message-id

[Wolfgang Denk]

Dear Krullen Van De Trap,

In message <20200920144832.CEAFA306467D@mailuser.nyi.internal> you wrote:
>
> > > sort -k 3 | sort -k 2
> > 
> > I don't think that does what you intend.
> > Anything achieved by the first sort is discarded by the second.
>
> Indeed it does not.
>
> Attached is a better version. I switched it also to use the unit
> separator (number 31, like number 29 but for fields of a record).
>
> So now the unnecessarily complex attack is to send a unit separator,
> and the simple attack is still to send the exact same message-id.
> I suppose you can check SPF, &c to mitigate either attack.

This does not work for me either.

It appears to have problems with messages that have no message-id
field at all (like those being archived throu a Fcc: header).  In
this case, $key will in my case look like this: '|wd@denx.de' and
all such messages will be flaged as dupes.


Best regards,

Wolfgang Denk

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