Bug 168661

Summary:	CVE-2005-3044 lost fput could lead to DoS
Product:	Red Hat Enterprise Linux 3	Reporter:	Mark J. Cox <mjc>
Component:	kernel	Assignee:	Ernie Petrides <petrides>
Status:	CLOSED ERRATA	QA Contact:	Brian Brock <bbrock>
Severity:	high	Docs Contact:
Priority:	medium
Version:	3.0	CC:	jparadis, lwang, peterm, petrides, sct, security-response-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:	reported=20050914,source=vendorsec,public=20050909,impact=important
Fixed In Version:	RHSA-2006-0140	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2006-01-19 16:00:03 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:
Bug Depends On:
Bug Blocks:	168424

Comment 2 Jim Paradis 2005-09-19 19:02:35 UTC

Can we characterize the severity of this issue?  The referenced fix has been
made upstream in 2.6 but not 2.4, and to do so would require backporting
fget_light()/fput_light().  I wonder if this is too invasive for a late
update... adding sct to cc list for his opinion.

Comment 3 Stephen Tweedie 2005-09-19 20:28:00 UTC

It's worse than just a missing fput().  The 2.4 code does:

	struct file *file = fget(fd);
	struct tty_struct *real_tty;

	if (!fd)
		return -EBADF;

It's checking fd for != 0 instead of file.  So it's (a) failing to operate
correctly if fd == 0 (which is a perfectly legal fd), and is (b) failing to
detect when fget() returns NULL. 

The fix is simple and localised.  There is no need at all to back-port
fget/fput_light() --- those are optimisations available only in 2.6.  For 2.4,
just use fget()/fput().

Comment 7 Ernie Petrides 2005-10-18 06:28:42 UTC

Fix posted for internal review on 17-Oct-2005.

Comment 8 Ernie Petrides 2005-10-20 05:46:03 UTC

A fix for this problem has just been committed to the RHEL3 U7
patch pool this evening (in kernel version 2.4.21-37.6.EL).

Comment 10 Ernie Petrides 2006-01-11 23:33:31 UTC

A fix for this problem has also been committed to the RHEL3 E7
patch pool this evening (in kernel version 2.4.21-37.0.1.EL).

Comment 12 Red Hat Bugzilla 2006-01-19 16:00:04 UTC

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2006-0140.html