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IDProjectCategoryView StatusLast Update
0005333unrealircdpublic2019-10-09 18:13
Reportersyzop Assigned Tosyzop  
Status resolvedResolutionfixed 
Fixed in Version5.0.0-alpha4 
Summary0005333: U5: control channel characters / utf8
DescriptionAs I mentioned in it is a problem if non-utf8 characters are allowed in channel names. Regardless of websocket, some configuration/control is likely a good idea.

At this time we don't have some kind of universal anti-look-alike system, which is what another IRCv3 effort is about..

I'm thinking of some options here like:
1. the current policy, block only ASCII <32
2. only valid utf8
3. only a-zA-Z0-9 and some characters, effectively block high ascii / block utf8

And I think the default should change from option 1 to option 2.
A more security conscious decision would be option 3, due to the lack of lookalike checking, but that's too strict for a default I think.
TagsNo tags attached.
3rd party modules


child of 0005279 closedsyzop UnrealIRCd 5 master tracking issue 



2019-09-22 18:45

administrator   ~0020928

commit 5a57eec4c71e2d3c7144a530f3e2679c49558e97 (HEAD -> unreal50, origin/unreal50)
Author: Bram Matthys <[email protected]>
Date: Sun Sep 22 18:40:29 2019 +0200

    Channel names must now be valid UTF8 by default.
    We actually have 3 possible settings of set::allowed-channelchars:
    utf8: Channel must be valid UTF8, this is the new default
    ascii: A very strict setting, for example in use at freenode,
           the channel name may not contain high ascii or UTF8
    any: A very loose setting, which allows almost all characters
           in the channel name. This was the OLD default, up to and
           including UnrealIRCd 4. It is no longer recommended.
    For most networks this new default setting of utf8 will be fine, since
    by far most IRC clients use UTF8 for many years already.
    If you have a network that has a significant portion of chatters
    that are on old non-UTF8 clients that use a specific character set
    then you may want to use set { allowed-nickchars any; }
    Some Russian and Ukrainian networks are known to need this.
    Devs: src/utf8.c has been added which will be used by this and
    by other functionality later.


2019-09-22 18:47

administrator   ~0020929

Last edited: 2019-09-22 18:47

It should be noted that clean_channelname() is only called for local creates, or at least in JOIN.
I'm leaving this issue open because I still need to communicate this setting between UnrealIRCd servers. We should refuse to link if the settings differ I think since that would be a confusing situation where you can join channels on server A but not on B.


2019-10-06 19:52

administrator   ~0020943

I have the sending of PROTOCTL in my queue already, but... not yet the parsing and rejecting. Had other things to do the rest of the day.

Also... we have U4 of course, so see if we could somehow warn about things but not be too noisy eg not for every remote JOIN.


2019-10-09 18:13

administrator   ~0020947

commit 22dec96f9a5dcf5edb0cb177dfed963b53b8bf62 (HEAD -> unreal50, origin/unreal50)
Author: Bram Matthys <[email protected]>
Date: Wed Oct 9 17:55:23 2019 +0200

    No clean_channelname() anymore but a valid_channelname() function. Also,
    deal with servers with different set::allowed-channelchars settings:
    * We reject the link if set::allowed-channelchars settings differ between
      UnrealIRCd 5 servers.
    * For the case where you have a mixed network consisting of UnrealIRCd 4.x
      and UnrealIRCd 5.x servers we try not to desync, BUT will not allow
      anyone to join the invalid channels locally. For IRCOps a message is
      printed with additional information on such a failed JOIN attempt.
    for the different settings, which are best and U4<->U5 advice.

Issue History

Date Modified Username Field Change
2019-07-18 17:39 syzop New Issue
2019-08-18 15:14 syzop Relationship added child of 0005279
2019-08-18 15:17 syzop View Status private => public
2019-08-18 15:29 syzop Status new => acknowledged
2019-09-22 18:45 syzop Note Added: 0020928
2019-09-22 18:47 syzop Note Added: 0020929
2019-09-22 18:47 syzop Note Edited: 0020929
2019-10-06 19:52 syzop Note Added: 0020943
2019-10-09 18:13 syzop Assigned To => syzop
2019-10-09 18:13 syzop Status acknowledged => resolved
2019-10-09 18:13 syzop Resolution open => fixed
2019-10-09 18:13 syzop Fixed in Version => 5.0.0-alpha4
2019-10-09 18:13 syzop Note Added: 0020947