Mail with single \r, partial fetch, error "Broken virtual size in mailbox"

7 Jan 2025

      I run Dovecot 2.3.21 with the mdbox mailbox format.
If I do a certain partial fetch on a mail with a single carriage return
\r Dovecot closes the connection and logs the following error:
Error: Mailbox INBOX: Deleting corrupted cache record uid=1: UID 1:
Broken virtual size in mailbox INBOX:
read(/var/spool/dovecot/user/storage/m.1): FETCH BODY[]<18.100> got too
little data: 5 vs 6
This happens every time, doveadm force-resync doesn't help.
Here's how to reproduce the issue:
Deliver a mail with a single carriage return \r (here after the
header/body separator, but that's not important):
echo -ne "Subject: Test\r\n\r\n\rBody\r\n" | doveadm save -u user
Then do a partial fetch from a specific offset:
. fetch 1 body[]<18.100>

1 FETCH (BODY[]<18> {6}
ody
Connection closed by foreign host.

Offset 18 with length 6 should "Body\r\n", that's why the response is 1
byte short ("got too little data: 5 vs 6" in the error message), by why
is \r causing this? Other offsets seem to work.

Ewald Dieterich

Timo Sirainen

Aki Tuomi

Ewald Dieterich

Schulz

Aki Tuomi

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