[Bug]: DNS CNAME record is always queried, even when the query for an A record already succeeded

georglauterbach commented 1 month ago

⚠️ This issue respects the following points: ⚠️

[X] This is a bug, not a question or a configuration/webserver/proxy issue.
[X] This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
[X] Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
[X] I agree to follow Nextcloud's Code of Conduct.

Bug description

I am looking at this code:

https://github.com/nextcloud/server/blob/4281ce6fa1bb8235426099d720734d2394bec203/lib/private/Http/Client/DnsPinMiddleware.php#L61-L89

[!IMPORTANT]

I am by no means a PHP expert, please tell me if I am mistaken.

To me, the way the code is constructed would indicate that CNAME is always queried, even when A succeeded. This aligns with what I am observing in my DNS server logs:

[INFO] 10.10.0.38:42508 - 60413 "CNAME IN updates.nextcloud.com. udp 50 false 1200" NOERROR qr,rd,ra 116 0.039573751s
[INFO] 10.10.0.38:46316 - 26341 "CNAME IN updates.nextcloud.com.cloud.svc.cluster. udp 68 false 1200" NXDOMAIN qr,aa,rd,ra 132 0.000151319s
[INFO] 10.10.0.38:42074 - 34897 "CNAME IN updates.nextcloud.com.cluster. udp 58 false 1200" NXDOMAIN qr,aa,rd,ra 122 0.000110026s
[INFO] 10.10.0.38:54477 - 22629 "CNAME IN apps.nextcloud.com.cloud.svc.cluster. udp 65 false 1200" NXDOMAIN qr,aa,rd,ra 129 0.000151308s
[INFO] 10.10.0.38:49188 - 36978 "CNAME IN www.nextcloud.com.cloud.svc.cluster. udp 64 false 1200" NXDOMAIN qr,aa,rd,ra 128 0.000266391s
[INFO] 10.10.0.38:48706 - 44842 "CNAME IN www.nextcloud.com.cluster. udp 54 false 1200" NXDOMAIN qr,aa,rd,ra 118 0.000134442s
[INFO] 10.10.0.38:40937 - 47170 "CNAME IN nextcloud.com. udp 42 false 1200" NOERROR qr,rd,ra 108 0.040937649s
[INFO] 10.10.0.38:57557 - 28949 "CNAME IN nextcloud.com.svc.cluster. udp 54 false 1200" NXDOMAIN qr,aa,rd,ra 118 0.000163416s

Wouldn't it make more sense to skip CNAME when canHaveCnameRecord is false, and we should set canHaveCnameRecord outside the loop?

Steps to reproduce

Run NC
Look at DNS server logs

Expected behavior

When canHaveCnameRecord is false, we should not query for CNAME.

Nextcloud Server version

29

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

PostgreSQL

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

[ ] Default user-backend (database)
[ ] LDAP/ Active Directory
[ ] SSO - SAML
[ ] Other

Configuration report

I will deliver upon request; I do not think the config is important for this issue.

List of activated Apps

I will deliver upon request; I do not think the config is important for this issue.

Nextcloud Signing status

I will deliver upon request; I do not think the config is important for this issue.

Nextcloud Logs

I will deliver upon request; I do not think the config is important for this issue.

Additional info

This is not a showstopper in any way; I just think the behavior is neither expected nor desirable.

georglauterbach commented 3 weeks ago

@solracsf any progress or update on this? I usually cannot afford to keep issues open for a long time; otherwise I lose the overview. The fix for this should also take not more than 5 minutes, for me maybe 20 considering I do not know PHP.

solracsf commented 3 weeks ago

any progress or update on this

If there isn't any PR attached, no. Feel free to submit one to be reviwed 👍

georglauterbach commented 3 weeks ago

@solracsf please take a look at #48675 :)

nextcloud / server