Bug 1670043

Summary:	glibc: libresolv should use IP_RECVERR/IPV6_RECVERR to avoid long timeouts [rhel-8]
Product:	Red Hat Enterprise Linux 8	Reporter:	Florian Weimer <fweimer>
Component:	glibc	Assignee:	Patsy Griffin <pfrankli>
Status:	CLOSED ERRATA	QA Contact:	qe-baseos-tools-bugs
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	8.1	CC:	ashankar, codonell, dj, fweimer, mnewsome, pfrankli, skolosov
Target Milestone:	rc	Keywords:	Patch
Target Release:	8.1
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	glibc-2.28-63.el8	Doc Type:	No Doc Update
Doc Text:		Story Points:	---
Clone Of:	1670028	Environment:
Last Closed:	2019-11-05 21:29:04 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:	1670028
Bug Blocks:	1670041, 1684559

Description Florian Weimer 2019-01-28 13:34:04 UTC

+++ This bug was initially created as a clone of Bug #1670028 +++

The Linux kernel does not forward certain ICMP errors to userspace unless IP_RECVERR/IPV6_RECVERR is specified.  We should use this socket option in the DNS stub resolver, as suggested in the upstream bug.

Comment 3 Florian Weimer 2019-06-04 14:31:50 UTC

Upstream commit:

commit 08504de71813ddbd447bfbca4a325cbe8ce8bcda
Author: Florian Weimer <fweimer>
Date:   Tue Mar 12 11:40:47 2019 +0100

    resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]
    
    The Linux kernel suppresses some ICMP error messages by default for
    UDP sockets.  This commit enables full ICMP error reporting,
    hopefully resulting in faster failover to working name servers.

Hurd-specific follow-on fix (optional):

commit 043440e761d395e1f507d9faa6e82b3fe4536c3f
Author: Florian Weimer <fweimer>
Date:   Wed Mar 13 14:58:58 2019 +0100

    hurd: Add no-op version of __res_enable_icmp [BZ #24047]
    
    Mach does not support IP_RECVERR, so replace this function with a
    stub in a sysdeps override for Hurd.
    
    This fixes commit 08504de71813ddbd447bfbca4a325cbe8ce8bcda
    ("resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]").

For verification, I think it is sufficient to check that strace shows the additional setsockopt call.

Comment 5 Sergey Kolosov 2019-09-09 07:05:54 UTC

Verified with strace

Comment 7 errata-xmlrpc 2019-11-05 21:29:04 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2019:3513