RHBA-2011:1647 - Bug Fix Advisory

Topic

An updated ksh package that fixes various bugs is now available for Red Hat
Enterprise Linux 6.

Description

KSH-93 is the most recent version of the KornShell by David Korn of AT&T Bell
Laboratories. KornShell is a shell programming language which is also compatible
with sh, the original Bourne Shell.

This updated ksh package includes fixes for the following bugs:

• Previously, ksh did not always wait for a pipeline to complete when the

pipefail option was used. Consequently, a failed exit status was erroneously
reported even when the pipeline had not failed. With this update, the code has
been improved and the pipefail option now functions as expected. (BZ#702016)

• File name completion used after an environment variable failed and ksh

reported a "bad substitution" error. With this update, an upstream patch has
been applied which fixes the problem. (BZ#702015).

• When running a ksh script the exit code of a child process was not preserved.

Consequently, when a script asked for such an exit code, the wrong value was
reported. With this update, an upstream patch has been applied which fixes the
problem. (BZ#702013, BZ#728900)

• In POSIX functions, a function defined without using the, "function", keyword,

the value of the variable "$0" was changed to the name of the function instead
of keeping the original value, the name of the caller function. With this update
an upstream patch has been applied to correct the code and ksh keeps the name of
the caller function in "$0" as expected. (BZ#702011)

• Previously, when the ksh built-in "kill" command was called with a very large,

non-existent PID value, it was interpreted as " -1". The "-1" argument to the
kill command is for terminating all processes. Consequently, all processes owned
by the user were killed. With this update a patch has been applied and ksh now
checks for a valid process ID. (BZ#701890)

• If the IFS variable was unset inside a function used in a script, the memory

being used was erroneously freed. Consequently, ksh would terminate
unexpectedly. With this update, an upstream patch has been applied which still
allows the IFS variable to be unset, but no longer frees the memory. Thus the
problem is fixed, and ksh no longer crashes in the scenario described.
(BZ##683734)

• Previously, ksh treated an array declaration as a definition. Consequently,

the array contained one element after the declaration. This bug has been fixed,
and now an array is correctly reported as empty after a declaration. (BZ#702014)

• Previously, when using ksh, ksh became unresponsive when pipes were used in a

"eval" argument. With this update an upstream patch has been applied and the ksh
no longer hangs in the scenario described. (BZ#742244)

• ksh could return the exit code of the previous process to have used the same

PID number, when PID numbers were being reused after many hundreds of iterations
of a script. With this update the code has been fixed and the error no longer
occurs in the scenario described. (#743842)

All users of ksh are advised to upgrade to this updated package, which fixes
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/kb/docs/DOC-11259

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 - 683734 - ksh crashes when IFS is unset inside a function
• BZ - 701890 - misprocessing of invalid PID argument for ksh built-in kill
• BZ - 702008 - KSH default path missing 'cwd' /bin:/usr/bin missing colon at the end
• BZ - 702015 - completion after an environment variable results in a "bad substitution" error
• BZ - 702016 - pipefail option causes intermittent failure of 'ls|! grep'
• BZ - 728900 - wait fails on pid of co-process
• BZ - 742244 - ksh script never comes back

CVEs

(none)

References

(none)