RHBA-2014:0795 - Bug Fix Advisory

Topic

Updated rsh packages that fix several bugs are now available for Red Hat
Enterprise Linux 6.

Description

The rsh packages contain programs which allow users to run commands on remote
machines, log in to other machines, copy files between machines (rsh, rlogin and
rcp), and provide an alternate method of executing remote commands (rexec). All
of these programs are run by the xinetd daemon and can be configured using the
Pluggable Authentication Modules (PAM) system and configuration files in the
/etc/xinetd.d/ directory.

This update fixes the following bugs:

• Previously, the rshd daemon performed redundant calls of the setpwent() and

endpwent() functions. As a consequence, rshd queried Network Information
Security (NIS) servers on every remote shell (rsh) access. With this update,
these redundant calls have been removed and rshd no longer contacts NIS servers
unnecessarily. (BZ#749283)

• Prior to this update, the maximum number of command line arguments for the rsh

application was not limited. However, the volume of data buffer allocated to the
arguments is always finite. Consequently, rshd terminated unexpectedly when it
attempted to allocate the buffer to commands with a vast number of arguments.
This update implements a limit for command-line arguments in rsh, and the
described rshd crash no longer occurs. (BZ#802367)

• Previously, the pam_close_session() function was not called when a remote copy

(rcp) connection completed. As a consequence, the PAM session did not terminate
correctly. With this update, pam_close_session() is called and the PAM session
terminates as intended. (BZ#1098955)

• Prior to this update, the rsh application was optimized through strict

aliasing rules, even though it is not a performance-sensitive application. As a
consequence, the GNU compiler collection (GCC) generated warning messages about
breaking the strict-aliasing rules, despite correct functionality being the
priority for rsh. With this update, strict aliasing has been disabled for rsh.
Therefore, GCC now ignores the strict aliasing rules and no longer interrupts
rsh processes with warning messages. However, this may also lead to a slight
decrease in performance. (BZ#1094360)

Users of rsh are advised to upgrade to these updated packages, which fix these
bugs.

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/site/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 1094360 - Disable strict-aliasing optimization for rsh

CVEs

(none)

References

(none)