rsyncd.conf 'host allow' entries don't work properly for DNS entries with IPV6 addresses

[bchill]

Hello,

If I disable reverse lookups and keep forward lookups enabled, access works as expected for fqdn entries in "hosts allow" that have only A records (ipv4) records but not for AAAA records (ipv6) when those hosts connect via ipv6. I get this error:

    @ERROR: access denied to opt from UNDETERMINED (2606:2800:220:1:248:1893:25c8:1946)

    # cat /etc/rsyncd.conf
    reverse lookup = false
    forward lookup = true
    read only = true
    list = false
    hosts allow = a.example.com, b.example.com

    [opt]
            path = /opt
            comment = whole opt tree

    # host a.example.com
    a.example.com has address 93.184.216.34

    # host b.example.com
    b.example.com has IPv6 address 2606:2800:220:1:248:1893:25c8:1946

(note that the above hosts/IPs are fictitious and/or loosely used)

rsync from a.example.com succeeds; rsync from b.example.com does not.

PTR records that are unset, set or don't match don't seem to have any effect (and they shouldn't).

This is for rsync 3.1.3 on Rocky 8 (rsync-3.1.3-19.el8_7.1.x86_64). This seems like either a bug or incomplete implementation of ipv6, I searched but could not find any reports of this issue; that leads me to believe that this isn't something that is working in the current version, either.

[fauno]

same on alpine linux 3.21 with rsync 3.4.0