dovecot - Jan 2020 - Bug: Regex doesn't match ungreedy

Hello,

first the mandatory dovecot specs:

- dovecot 2.3.9.2-1

- Operating system: Archlinux

- x84 cpu

- ext4 filesystem


My problem is that the sieve regex filter doesn't seem to match
ungreedely so the regex:

^(Re: |)\\[(.*?)\\/(.*?)\\]

evaluates the last capturing group of

[matrix-org/synapse] [Don't merge!!] Backport fix for MAU limits to
v1.8.0? (#6763)

to

synapse] [Don't merge!!

wich should have been

synapse

Best Regards
Lorenz Steinert

Hi,

Op 23-1-2020 om 11:39 schreef Lorenz Steinert:
> Hello,
>
> first the mandatory dovecot specs:
>
> - dovecot 2.3.9.2-1
>
> - Operating system: Archlinux
>
> - x84 cpu
>
> - ext4 filesystem
>
>
> My problem is that the sieve regex filter doesn't seem to match
> ungreedely so the regex:
>
> ^(Re: |)\\[(.*?)\\/(.*?)\\]
>
> evaluates the last capturing group of
>
> [matrix-org/synapse] [Don't merge!!] Backport fix for MAU limits to
> v1.8.0? (#6763)
>
> to
>
> synapse] [Don't merge!!
>
> wich should have been
>
> synapse
Sieve is using the POSIX regular expression syntax? and semantics for 
the "regex" extension. Pigeonhole uses the libc implementation of that
(regcomp(), regexec()), so if you think this behavior is wrong (I don't 
really know), you should report it to those responsible for your libc 
implementation.

Regards,

Stephan.