5.6 - RHSA-2012:1149

Problem Description:

An updated sudo package that fixes one security issue and several bugs 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

3. Description:

The sudo (superuser do) utility allows system administrators to give certain users the ability to run commands as root.

An insecure temporary file use flaw was found in the sudo package's post-uninstall script. A local attacker could possibly use this flaw to overwrite an arbitrary file via a symbolic link attack, or modify the contents of the "/etc/nsswitch.conf" file during the upgrade or removal of the sudo package. (CVE-2012-3440)

This update also fixes the following bugs:

* Previously, sudo escaped non-alphanumeric characters in commands using "sudo -s" or "sudo -" at the wrong place and interfered with the authorization process. Some valid commands were not permitted. Now, non-alphanumeric characters escape immediately before the command is executed and no longer interfere with the authorization process. (BZ#844418)

* Prior to this update, the sudo utility could, under certain circumstances, fail to receive the SIGCHLD signal when it was executed from a process that blocked the SIGCHLD signal. As a consequence, sudo could become suspended and fail to exit. This update modifies the signal process mask so that sudo can exit and sends the correct output. (BZ#844419)

* The sudo update RHSA-2012:0309 introduced a regression that caused the Security-Enhanced Linux (SELinux) context of the "/etc/nsswitch.conf" file to change during the installation or upgrade of the sudo package. This could cause various services confined by SELinux to no longer be permitted to access the file. In reported cases, this issue prevented PostgreSQL and Postfix from starting. (BZ#842759)

* Updating the sudo package resulted in the "sudoers" line in "/etc/nsswitch.conf" being removed. This update corrects the bug in the sudo package's post-uninstall script that caused this issue. (BZ#844420)

* Prior to this update, a race condition bug existed in sudo. When a program was executed with sudo, the program could possibly exit successfully before sudo started waiting for it. In this situation, the program would be left in a zombie state and sudo would wait for it endlessly, expecting it to still be running. (BZ#844978)

All users of sudo are advised to upgrade to this updated package, which contains backported patches to correct these issues.

4. Solution:

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 https://access.redhat.com/knowledge/articles/11258

5. Bugs fixed (http://bugzilla.redhat.com/):

842759 - selinux blocks postgresql startup 844420 - sudo 1.7.2p1-14.el5_8 removed sudoers line from nsswitch.conf 844442 - CVE-2012-3440 sudo: insecure temporary file use in RPM %postun script 844978 - Sudo has racecondition leaving sudo with its zombie child running forever