dovecot - Jan 2021 - lzma mdboxes with unexpected EOF

Hi,

I'm running dovecot 2.3.13 (until 05.01. it was 2.3.11.3) on Arch Linux
and used lzma compressed mdboxes. Yesterday a user called me that she is
missing all mails from the beginning of the month until now. I took a
look into the logs and saw several "lzma.read [...] unexpected EOF at
<....>". As I had no clue why the mdboxes are broken, I tried to
convert
all 3 mailboxes to Maildir using "doveadm sync" to prevent further
issues and stumbled upon several lzma errors for mdbox files of my own
user. So I wrote a script which took the offset and size via "doveadm
dump" und then dds the xz parts out of the broken mdboxes and extracts
them via 7z.

But I'm wondering why that happened at all. I stumpled upon [1] but
there was no further discussion about it.

Best Regards
Bjoern

[1]https://dovecot.org/pipermail/dovecot/2019-September/117007.html

Hi,
> 
> But I'm wondering why that happened at all. I stumpled upon [1] but
> there was no further discussion about it.
> 
it seems it was caused by a bug mentioned in 2.3.13's changelog:

- lib-compression: Using xz/lzma compression in v2.3.11 could have
  written truncated output in some situations. This would result in
  "Broken pipe" read errors when trying to read it back.

So, sorry for the noise :)

Best Regards
Bjoern