Bug 223075 (CVE-2006-6939)

Summary:	CVE-2006-6939 Insecure use of temporary file in ed
Product:	[Fedora] Fedora	Reporter:	Lubomir Kundrak <lkundrak>
Component:	ed	Assignee:	Karsten Hopp <karsten>
Status:	CLOSED ERRATA	QA Contact:	Ben Levenson <benl>
Severity:	low	Docs Contact:
Priority:	low
Version:	rawhide	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
URL:	http://www.frsirt.com/english/advisories/2006/4573
Whiteboard:	impact=low,source=cve,reported=20070117,public=20071111
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2007-01-18 12:03:22 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:	223072
Bug Blocks:

Description Lubomir Kundrak 2007-01-17 19:43:02 UTC

+++ This bug was initially created as a clone of Bug #223072 +++

Description of problem:

Version 0.3 of GNU ed replaced use of unsecure mktemp() followed
by fopen() in buf.c:open_sbuf() with tmpnam(). The former construction
is vulnerable to race condition, where a malicous user can create
the temporary file between two function calls, as they are non-atomic,
and then either read or write the contents of the file, or make it
a symbolic link to a file owned by the victim resulting in its overite.

Version-Release number of selected component (if applicable):

GNU ed 0.2, in RHEL{2.1,3,4,5} and FC{5,6}

How reproducible:

Time-dependent race condition, very unlikely.

Steps to Reproduce:
1. Attempt to guess the filename returned by mktemp() and attempt
create it while being schelduled between mktemp() and fopen() calls.

-- Additional comment from lkundrak on 2007-01-17 14:34 EST --
Created an attachment (id=145853)
Backported patch that corrects CVE-2006-6939 GNU ed insecure tmp file handling.