Bug 178055

Summary:	reverse lookups can crash squid with 'signal 6'
Product:	Red Hat Enterprise Linux 3	Reporter:	illtud <illtud.daniel>
Component:	squid	Assignee:	Martin Stransky <stransky>
Status:	CLOSED DUPLICATE	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	3.0
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2006-01-18 11:35:59 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description illtud 2006-01-17 17:13:56 UTC

From Bugzilla Helper:
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Description of problem:
Some requests for numeric IP address referenced pages will cause squid child processes to crash. Too many of these and squid will bail out altogether due to 'repeated, frequent failures'.


Version-Release number of selected component (if applicable):
squid-2.5.STABLE3-6.3E.14

How reproducible:
Always

Steps to Reproduce:
1. Have a dstdomain acl so that squid performs reverse lookups on numeric IP addresses
2. Send a number of numeric IP address requests to squid

  

Actual Results:  1. Watch child processes die 'due to signal 6'
2. Too many of these and the parent process will die 'Exiting due to repeated, frequent failures'

Expected Results:  Squid retuns the requests.

Additional info:

Googling found this thread, which enabled me to workaround the problem (by removing the dstdomain acl for the time being):

http://archives.neohapsis.com/archives/linux/debian/2005-q3/0147.html

Some detective work was done later in the thread:
http://archives.neohapsis.com/archives/linux/debian/2005-q3/0545.html

Seems to have been fixed in squid upstream:
http://archives.neohapsis.com/archives/linux/debian/2005-q3/0563.html

Fixed in one of these squid bugzillas:
http://www.squid-cache.org/bugs/buglist.cgi?query_format=specific&order=relevance+desc&bug_status=__closed__&product=Squid&content=rfc1035.c

Comment 1 illtud 2006-01-17 17:28:42 UTC

To reproduce, it may be that the host being reverse looked-up must have a PTR
record and a CNAME. That would explain why the problem only became apparent to
us today (after that specific host was given a CNAME). This may point to the
squid bug being:

http://www.squid-cache.org/bugs/show_bug.cgi?id=1136

although that refers to multiple PTR records, rather than PTR & CNAME, but I'd
imagine that you'd want dstdomain (and other acl DNS lookups) to match CNAMEs as
well, so it wouldn't surprise me if this would trigger it as well.

Comment 2 Martin Stransky 2006-01-18 11:35:59 UTC

Thanks for your report, it will be fixed in the next RHEL3/4 update.

*** This bug has been marked as a duplicate of 165367 ***