RHBA-2015:2208 - Bug Fix Advisory

Topic

Updated zsh packages that fix several bugs and add one enhancement are now available for Red Hat Enterprise Linux 7.

Description

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

This update fixes the following bugs:

• Prior to this update, the speed of pattern matching in zsh 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. As a result, the speed of pattern matching in zsh is no longer affected by the count of subsequent "*" symbols. (BZ#1130418)
• Previously, when zsh was not able to close the requested file descriptor, an error message was printed. With this update, the error message is suppressed if the user has no explicit control over the file descriptor being closed. (BZ#1131191)
• Previously, zsh did not correctly check strings containing double square brackets ("[[...]]"). As a consequence, the zsh syntax check failed when testing scripts that contained these characters. With this update, zsh checks strings with double square brackets correctly, and scripts that contain them no longer fail the testing. (BZ#1146512)
• Previously, when the signal handler attempted to execute a memory allocation function and a signal was raised in the meantime, a deadlock occurred and the zsh process became unresponsive. With this update, the calls to memory allocation functions in signal handlers are wrapped so that signals are queued until the affected functions complete. As a result, the described deadlock no longer occurs in zsh. (BZ#1163823)
• Previously, the /etc/zshenv configuration file contained a comment stating that /etc/zshenv is not sourced if zsh is executed with the -f option, which is not true, because /etc/zshenv is always sourced. With this update, the comment has been replaced with a correct one and so no longer causes confusion. (BZ#1164312)
• Previously, 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#1165118)
• Previously, the code that initializes environment variables in zsh did not correctly handle NULL values. As a consequence, zsh terminated unexpectedly when attempting to check the syntax of a shell script in ksh emulation mode. This update fixes the handling of NULL values, and the syntax check now works as expected when zsh runs in ksh emulation mode. (BZ#1222867)
• Previously, zsh did not correctly parse command substitutions. As a consequence, zsh in some cases reported syntax errors for syntactically valid shell scripts. With this update, the parser has been fixed to parse shell scripts correctly. (BZ#1241023)

In addition, this update adds the following enhancement:

• With this update, the "wait" built-in command of zsh can now wait for and obtain the exit status of any selected background process, which no longer needs to be the latest created one. (BZ#1150554)

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

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 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux for Power, little endian 7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.5 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 s390x
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.7 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.6 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.4 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.3 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 ppc64le

Fixes

• BZ - 1150554 - zsh wait builtin does not work for already exited processes [RHEL-7]
• BZ - 1164312 - incorrect comment in default zshenv configuration file [RHEL-7]
• BZ - 1222867 - zsh in ksh emulation mode, coredumps when trying to check the syntax of a shell script
• BZ - 1241023 - case in a for loop inside subshell causes syntax error

CVEs

(none)

References

• http://www.redhat.com/security/updates/classification/#normal