RHBA-2015:1273 - Bug Fix Advisory

Topic

Updated zsh packages that fix several bugs and add various enhancements are now
available for Red Hat Enterprise Linux 6.

Description

The zsh shell is a command interpreter usable as an interactive login shell and
as a shell script command processor. Zsh resembles the ksh shell (the Korn
shell), but includes many enhancements. Zsh supports command-line editing,
built-in spelling correction, programmable command completion, shell functions
(with autoloading), a history mechanism, and more.

The zsh packages have been upgraded to upstream version 4.3.11, which provides a
number of bug fixes and enhancements over the previous version. Notably, the
upgrade includes the following changes:

• Parameter expansion has been enhanced to provide the ${NAME:OFFSET} and

${NAME:OFFSET:LENGTH} syntaxes for substrings and subarrays present in several
other shells.

• Numeric expansion with braces has been extended, which allows users to specify

a step in the numeric expansion, for example {3..9..2}. (BZ#1132710)

This update also fixes the following bugs:

• Prior to this update, when the "jobs -Z" built-in zsh command was invoked,

some environment variables were overwritten. An upstream patch has been applied
to preserve the environment variables when "jobs -Z" is run, thus fixing this
bug. (BZ#878324)

• Due to a parser error, the zsh shell previously interpreted variable

assignments as other commands, and attempted to execute them when zsh was
running in ksh compatibility mode. This update modifies the underlying code to
interpret variable assignments as expected in the described situation.
(BZ#1146119)

• Prior to this update, the speed of the pattern matching in the zsh shell

decreased when multiple subsequent occurrences of the "*" wildcard symbol were
used in a pattern. An upstream patch has been applied on zsh source code to
optimize the implementation of pattern matching in zsh with redundant "*"
symbols in the pattern. As a result, the speed of pattern matching in zsh is no
longer affected by the count of subsequent "*" symbols. (BZ#1131172)

• An incorrect comment in the /etc/zshenv configuration file caused that the

users erroneously expected that the file takes no effect if the zsh shell is
started with the "-f" option. The comment in the /etc/zshenv file has been
changed to describe the configuration file correctly. (BZ#1103697)

• When processing overly-long input data, the zsh shell terminated unexpectedly

because of a stack-based buffer overflow. With this update, arrays of variable
sizes are allocated on heap memory instead of stack memory, thus fixing the bug.
(BZ#567215)

• Prior to this update, the description of emulation mode in the zsh man page

was incomplete. With this update, the documentation has been updated to provide
users with more information about the command that starts emulation mode.
(BZ#1104021)

Users of zsh are advised to upgrade to these updated packages, which fix these
bugs and add these enhancements.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/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 x86_64
• 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 (for IBM z Systems) 6 s390x

Fixes

• BZ - 1132710 - rebase zsh to 4.3.11

CVEs

(none)

References

(none)