Bug 168661 - CVE-2005-3044 lost fput could lead to DoS
CVE-2005-3044 lost fput could lead to DoS
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: kernel (Show other bugs)
x86_64 Linux
medium Severity high
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Assigned To: Ernie Petrides
Brian Brock
: Security
Depends On:
Blocks: 168424
  Show dependency treegraph
Reported: 2005-09-19 04:41 EDT by Mark J. Cox (Product Security)
Modified: 2007-11-30 17:07 EST (History)
6 users (show)

See Also:
Fixed In Version: RHSA-2006-0140
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2006-01-19 11:00:03 EST
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Comment 2 Jim Paradis 2005-09-19 15:02:35 EDT
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 16:28:00 EDT
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 02:28:42 EDT
Fix posted for internal review on 17-Oct-2005.
Comment 8 Ernie Petrides 2005-10-20 01:46:03 EDT
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 18:33:31 EST
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 11:00:04 EST
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.


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