Subject: Re: MSGNO and UID

From: Raul Dias <[email-masked]>
Date: Mon, 5 Nov 2001 19:06:27 -0300

>
>UIDs are uniquely assigned, and are never reused.
>
>Thus, MSGNO==UID can only happen in a mail store which assigns UIDs
>consecutively from 1, in a mailbox that has never had any messages expunged.

This raises another question.
how does c-client deals with a message that already has a X-UID set?
Does it corrects it, ignore it? Is is possible for a malicious mail to "poison"
the mailbox by sending an email with an X-UID lower higher set?

Or even worse.  how does it deal if we get a message like the 
"Mail System Internal Data" with X-IMAP set to something?

When seting the FLAGs in the c-client API to use UID instead of MSGNO, does it
have a performance hit?

Regards,

Raul Dias

---

From: Mark Crispin <[email-masked]>
Date: Mon, 5 Nov 2001 14:11:01 -0800 (PST)

On Mon, 5 Nov 2001 19:06:27 -0300, Raul Dias wrote:
> Does it corrects it, ignore it?

c-client attempts to correct it as best as it can.

> Is is possible for a malicious mail to "poison"

To a limited degree, yes.  But the worst impact of such poison is that
invalidation of the entire UID regime for that mailbox and start a new one.

> "Mail System Internal Data" with X-IMAP set to something?

X-IMAP only has effect with the very first message in the mailbox.  That's one
reason why the internal data message is your friend, since it holds on to that
first place even when all real messages are deleted.

> When seting the FLAGs in the c-client API to use UID instead of MSGNO, does
> it have a performance hit?

Yes, since c-client has to translate the UID to MSGNO.