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Bug 1646373

Summary:	glibc: Crash in getaddrinfo_a when thread creation fails
Product:	Red Hat Enterprise Linux 7	Reporter:	Florian Weimer <fweimer>
Component:	glibc	Assignee:	DJ Delorie <dj>
Status:	CLOSED ERRATA	QA Contact:	qe-baseos-tools-bugs
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	7.7	CC:	ashankar, codonell, dj, fweimer, mnewsome, pfrankli, skolosov
Target Milestone:	rc	Keywords:	Patch
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	glibc-2.17-269.el7	Doc Type:	No Doc Update
Doc Text:		Story Points:	---
Clone Of:
Clones:	1646379 1646381 (view as bug list)		Environment:
Last Closed:	2019-08-06 12:49:05 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:	1646379, 1646381
Bug Blocks:	1660844

Description Florian Weimer 2018-11-05 13:29:25 UTC

From the upstream bug report:

At line 237 in gai_misc.c:

lastp = requests_tail;
if (requests_tail == NULL)
  requests = requests_tail = newp;
else ...

If requests_tail was NULL then lastp remains NULL. 
Unfortunately if gai_create_helper_thread fails, lastp is de-referenced at line 267 which will cause a SIGSEGV.

Comment 1 Florian Weimer 2018-11-05 13:30:00 UTC

This should be reproducible with a custom malloc which fails after the right number of allocations.

Comment 3 Florian Weimer 2018-11-05 13:54:12 UTC

Upstream commit:

commit bd3b0fbae33a9a4cc5e2daf049443d5cf03d4251
Author: Andreas Schwab <schwab>
Date:   Mon Nov 5 12:47:30 2018 +0100

    libanl: properly cleanup if first helper thread creation failed (bug 22927)

Comment 6 Sergey Kolosov 2019-06-27 09:45:08 UTC

Verified with modified __gai_create_helper_thread() function which always returns -1 and a test that calls getaddrinfo_a(). In glibc-2.17-269.el7 getaddrinfo_a() doesn't crash but returns EAGAIN.

Comment 9 errata-xmlrpc 2019-08-06 12:49:05 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-2019:2118