Bug 1297099

Summary:	glibc: Do not fail name resolution if CNAMEs involve aliases which are not host names
Product:	Red Hat Enterprise Linux 7	Reporter:	Rupesh Patel <rupatel>
Component:	glibc	Assignee:	glibc team <glibc-bugzilla>
Status:	CLOSED WONTFIX	QA Contact:	qe-baseos-tools-bugs
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.3	CC:	ashankar, codonell, cww, fweimer, mnewsome, msweiker, pfrankli, ysoni
Target Milestone:	rc	Keywords:	Reopened
Target Release:	---
Hardware:	All
OS:	Linux
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Clone Of:
Clones:	1752133 (view as bug list)		Environment:
Last Closed:	2020-08-21 21:32:18 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1203710, 1752133

Description Rupesh Patel 2016-01-09 06:06:53 UTC

Commands which uses libc for resolving names can not resolve CNAME with wildcard chain.

rupesh ~ $ ping mint.lc.intuit.com
ping: unknown host mint.lc.intuit.com
rupesh ~ $ 

rupesh ~ $ host mint.lc.intuit.com
mint.lc.intuit.com is an alias for app.shared-prod.lc.a.intuit.com.
app.shared-prod.lc.a.intuit.com is an alias for *.pod-2-prod-2.lc-shared-production.lc.a.intuit.com.
*.pod-2-prod-2.lc-shared-production.lc.a.intuit.com is an alias for lc-pod-2-prod-elb-1kic5vmf4eodj-1038427872.us-west-2.elb.amazonaws.com.
lc-pod-2-prod-elb-1kic5vmf4eodj-1038427872.us-west-2.elb.amazonaws.com has address 52.35.104.45
lc-pod-2-prod-elb-1kic5vmf4eodj-1038427872.us-west-2.elb.amazonaws.com has address 52.10.3.222
lc-pod-2-prod-elb-1kic5vmf4eodj-1038427872.us-west-2.elb.amazonaws.com has address 52.35.237.236
rupesh ~ $ 

Upstream seems to have this bug reported but so far no more discussion on it. 

https://sourceware.org/bugzilla/show_bug.cgi?id=12154

One of our customer having Developer Support subscriptions asking for it. I do not find any bug opened for this so i have opened this bug.

Was there any discussion in this regards?
Was there any bug opened for it and rejected?
Is there any details available?

Comment 3 Florian Weimer 2016-01-09 08:59:19 UTC

(In reply to Rupesh Patel from comment #0)

> *.pod-2-prod-2.lc-shared-production.lc.a.intuit.com.

Technically, this is not a wildcard.  Wildcards are master zone file concept and not visible on the wire and to clients, and they cannot be used on the RHS of a CNAME.  RFC 1034 is ambiguous to whether this is valid or not because “*” is not a valid character in host names.

Comment 6 Florian Weimer 2019-02-15 09:39:15 UTC

*** Bug 1677525 has been marked as a duplicate of this bug. ***

Comment 11 Carlos O'Donell 2020-08-21 21:32:18 UTC

The Red Hat Platform Tools glibc team has reviewed this request and we will not be fixing this in RHEL 7.9. Consensus upstream is not decided and further work is required. Given that RHEL 7 is entering Maintenance Support 2 we feel that any change like this could be disruptive to existing installations. Instead we will track this in upstream glibc and try to resolve it there.

Comment 12 Florian Weimer 2022-08-10 09:36:26 UTC

Upstream patches posted:

[PATCH 00/13] nss_dns: Fix handling of non-host CNAMEs (bug 12154)
https://sourceware.org/pipermail/libc-alpha/2022-August/141338.html