(Red Hat Issues Fix) Rsync Bugs Let Users Bypass Chroot and Exclude/Filter Access Controls
SecurityTracker Alert ID: 1025821|
SecurityTracker URL: http://securitytracker.com/id/1025821
(Links to External Site)
Date: Jul 22 2011
Disclosure of system information, Disclosure of user information, Modification of system information, Modification of user information|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): prior to 3.0.0pre6|
Two vulnerabilities were reported in Rsync. A remote user can bypass access controls to access files on the target system.|
Users that have configured rsync as a writable rsync daemon are affected.
If the daemon is configured with the 'use chroot = no' setting, a remote user can cause rsync to create a symbolic link to a file located outside of the module's hierarchy.
If the daemon is configured with an "exclude", "exclude from", or "filter" option, a remote user can access restricted files. The remote user may be able to write to the file (in accordance with the file's permission).
A remote user can bypass access controls to access files on the target system.|
Red Hat has issued a fix for CVE-2007-6200.|
The Red Hat advisory is available at:
Vendor URL: rsync.samba.org/ (Links to External Site)
Access control error|
|Underlying OS: Linux (Red Hat Enterprise)|
|Underlying OS Comments: 5|
This archive entry is a follow-up to the message listed below.|
Source Message Contents
Subject: [RHSA-2011:0999-01] Moderate: rsync security, bug fix, and enhancement update|
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Red Hat Security Advisory
Synopsis: Moderate: rsync security, bug fix, and enhancement update
Advisory ID: RHSA-2011:0999-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2011-0999.html
Issue date: 2011-07-21
CVE Names: CVE-2007-6200
An updated rsync package that fixes one security issue, several bugs, and
adds enhancements is now available for Red Hat Enterprise Linux 5.
The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.
2. Relevant releases/architectures:
Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64
Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64
rsync is a program for synchronizing files over a network.
A flaw was found in the way the rsync daemon handled the "filter",
"exclude", and "exclude from" options, used for hiding files and preventing
access to them from rsync clients. A remote attacker could use this flaw to
bypass those restrictions by using certain command line options and
symbolic links, allowing the attacker to overwrite those files if they knew
their file names and had write access to them. (CVE-2007-6200)
Note: This issue only affected users running rsync as a writable daemon:
"read only" set to "false" in the rsync configuration file (for example,
"/etc/rsyncd.conf"). By default, this option is set to "true".
This update also fixes the following bugs:
* The rsync package has been upgraded to upstream version 3.0.6, which
provides a number of bug fixes and enhancements over the previous version.
* When running an rsync daemon that was receiving files, a deferred info,
error or log message could have been sent directly to the sender instead of
being handled by the "rwrite()" function in the generator. Also, under
certain circumstances, a deferred info or error message from the receiver
could have bypassed the log file and could have been sent only to the
client process. As a result, an "unexpected tag 3" fatal error could have
been displayed. These problems have been fixed in this update so that an
rsync daemon receiving files now works as expected. (BZ#471182)
* Prior to this update, the rsync daemon called a number of timezone-using
functions after doing a chroot. As a result, certain C libraries were
unable to generate proper timestamps from inside a chrooted daemon. This
bug has been fixed in this update so that the rsync daemon now calls the
respective timezone-using functions prior to doing a chroot, and proper
timestamps are now generated as expected. (BZ#575022)
* When running rsync under a non-root user with the "-A" ("--acls") option
and without using the "--numeric-ids" option, if there was an Access
Control List (ACL) that included a group entry for a group that the
respective user was not a member of on the receiving side, the
"acl_set_file()" function returned an invalid argument value ("EINVAL").
This was caused by rsync mistakenly mapping the group name to the Group ID
"GID_NONE" ("-1"), which failed. The bug has been fixed in this update so
that no invalid argument is returned and rsync works as expected.
* When creating a sparse file that was zero blocks long, the "rsync
- --sparse" command did not properly truncate the sparse file at the end of
the copy transaction. As a result, the file size was bigger than expected.
This bug has been fixed in this update by properly truncating the file so
that rsync now copies such files as expected. (BZ#530866)
* Under certain circumstances, when using rsync in daemon mode, rsync
generator instances could have entered an infinitive loop, trying to write
an error message for the receiver to an invalid socket. This problem has
been fixed in this update by adding a new sibling message: when the
receiver is reporting a socket-read error, the generator will notice this
fact and avoid writing an error message down the socket, allowing it to
close down gracefully when the pipe from the receiver closes. (BZ#690148)
* Prior to this update, there were missing deallocations found in the
"start_client()" function. This bug has been fixed in this update and no
longer occurs. (BZ#700450)
All users of rsync are advised to upgrade to this updated package, which
resolves these issues and adds enhancements.
Before applying this update, make sure all previously-released errata
relevant to your system have been applied.
This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
5. Bugs fixed (http://bugzilla.redhat.com/):
339971 - [RFE] Rebase rsync packages to version 3
407171 - CVE-2007-6200 rsync excluded content access restrictions bypass via symlinks
471182 - rsync errors: unexpected tag 3 [sender]
530866 - rsync --sparse does not properly copy sparse files
575022 - rsyncd gets confused with timezones when logging to syslog
616093 - EINVAL (Invalid argument) setting group --acls
690148 - Rsync instances stay in memory when using in daemon mode
700450 - Resource leaks revealed by Coverity scan.
6. Package List:
Red Hat Enterprise Linux Desktop (v. 5 client):
Red Hat Enterprise Linux (v. 5 server):
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
The Red Hat security contact is <firstname.lastname@example.org>. More contact
details at https://access.redhat.com/security/team/contact/
Copyright 2011 Red Hat, Inc.
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