Synopsis

ksh bug fix and enhancement update

Type/Severity

Bug Fix Advisory

Topic

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

Description

KornShell (KSH) is a Unix shell developed by AT&T Bell Laboratories, which is
backward-compatible with the Bourne shell (Bash) and includes many features of
the C shell. The most recent version is KSH-93. KornShell complies with the
POSIX.2 standard (IEEE Std 1003.2-1992).

The ksh package has been upgraded to upstream version 20120801, which provides a
number of bug fixes and enhancements over the previous version. (BZ#840568)

This update also fixes the following bugs:

• Previously, the ksh shell did not set any editing mode as default, which
  caused various usability problems in interactive mode and with shell
  auto-completion. This update sets emacs editing mode as default for new users.
  As a result, the usability is significantly improved and the shell
  auto-completion works as expected. (BZ#761551)
  
• Previously, the ksh internal counter of jobs was too small. Consequently, when
  a script used a number of subshells in a loop, a counter overflow could occur
  causing the ksh shell to terminate unexpectedly with a segmentation fault. This
  update modifies ksh to use bigger types for counter variables. As a result, ksh
  no longer crashes in the described scenario. (BZ#858263)
  
• Previously, the ksh shell did not compute an offset for fixed size variables
  correctly. As a consequence, when assigning a right-justified variable with a
  fixed width to a smaller variable, the new variable could have an incorrect
  content. This update applies a patch to fix this bug and the assignment now
  proceeds as expected. (BZ#903750)
  
• Previously, the output of command substitutions was not always redirected
  properly. Consequently, the output in a here-document could be lost. This update
  fixes the redirection code for command substitutions and the here-document now
  contains the output as expected. (BZ#913110)
  
• Using arrays inside of ksh functions, command aliases, or automatically loaded
  functions caused memory leaks to occur. The underlying source code has been
  modified to fix this bug and the memory leaks no longer occur in the described
  scenario. (BZ#921455, BZ#982142)
  
• Previously, the ksh SIGTSTP signal handler could trigger another SIGTSTP
  signal. Consequently, ksh could enter an infinite loop. This updated version
  fixes the SIGTSTP signal processing and ksh now handles the signal without any
  problems. (BZ#922851)
  
• Previously, the ksh shell did not resize the file descriptor list every time
  it was necessary. This could lead to memory corruption when several file
  descriptors were used. As a consequence, ksh terminated unexpectedly. This
  updated version resizes the file descriptor list every time it is needed, and
  ksh no longer crashes in the described scenario. (BZ#924440)
  
• Previously, the ksh shell ignored the "-m" argument specified by the command
  line. As a consequence, ksh did not enable monitor mode and the user had to
  enable it in a script. With this update, ksh no longer ignores the argument so
  that the user is able to enable monitor mode from the command line as expected.
  (BZ#960034)
  
• The ksh shell did not handle I/O redirections from command substitutions
  inside a pipeline correctly. Consequently, the output of certain commands could
  be lost. With this update, the redirections have been fixed and data is no
  longer missing from the command outputs. (BZ#994251)
  

Users of ksh 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.

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 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

Fixes

• BZ - 761551 - set default editing mode to emacs
• BZ - 922851 - exec a script causes a fork bomb when receiving SIGTSTP

CVEs

(none)

References

(none)

Red Hat Enterprise Linux Server 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
x86_64
ksh-20120801-10.el6.x86_64.rpm	SHA-256: 6613de5a86815781c6d468c89ceab873a3f844ae168e6ae79b9b685c0c620925
ksh-debuginfo-20120801-10.el6.x86_64.rpm	SHA-256: 2e64a178617b6dafcb9d1e4faf6ce0e1de234570d3ad2ee089b04282c54fc266
i386
ksh-20120801-10.el6.i686.rpm	SHA-256: 79ca957c34b46e0e97f8b96c40526419e1cdaaed9fadd1c73c317a594db72e27
ksh-debuginfo-20120801-10.el6.i686.rpm	SHA-256: d620eafe0ead4dbb322b3c67fcbc1465997d620bac55aa26b5fdce31bd367f3f

Red Hat Enterprise Linux Workstation 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
x86_64
ksh-20120801-10.el6.x86_64.rpm	SHA-256: 6613de5a86815781c6d468c89ceab873a3f844ae168e6ae79b9b685c0c620925
ksh-debuginfo-20120801-10.el6.x86_64.rpm	SHA-256: 2e64a178617b6dafcb9d1e4faf6ce0e1de234570d3ad2ee089b04282c54fc266
i386
ksh-20120801-10.el6.i686.rpm	SHA-256: 79ca957c34b46e0e97f8b96c40526419e1cdaaed9fadd1c73c317a594db72e27
ksh-debuginfo-20120801-10.el6.i686.rpm	SHA-256: d620eafe0ead4dbb322b3c67fcbc1465997d620bac55aa26b5fdce31bd367f3f

Red Hat Enterprise Linux Desktop 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
x86_64
ksh-20120801-10.el6.x86_64.rpm	SHA-256: 6613de5a86815781c6d468c89ceab873a3f844ae168e6ae79b9b685c0c620925
ksh-debuginfo-20120801-10.el6.x86_64.rpm	SHA-256: 2e64a178617b6dafcb9d1e4faf6ce0e1de234570d3ad2ee089b04282c54fc266
i386
ksh-20120801-10.el6.i686.rpm	SHA-256: 79ca957c34b46e0e97f8b96c40526419e1cdaaed9fadd1c73c317a594db72e27
ksh-debuginfo-20120801-10.el6.i686.rpm	SHA-256: d620eafe0ead4dbb322b3c67fcbc1465997d620bac55aa26b5fdce31bd367f3f

Red Hat Enterprise Linux for IBM z Systems 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
s390x
ksh-20120801-10.el6.s390x.rpm	SHA-256: b1d91008c4a1545340e20bb2f88095ac51478a9052bcbb003ee35506779c8564
ksh-debuginfo-20120801-10.el6.s390x.rpm	SHA-256: 1849f4b46387a1d34e67af9af694b7c0ab524a3c6cd45aba1f15dc4b287f47d0

Red Hat Enterprise Linux for Power, big endian 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
ppc64
ksh-20120801-10.el6.ppc64.rpm	SHA-256: 4b4db12464c59f821c9b4cea46b07c7e05d27f13b6ffa371ea0158077cfaeb3e
ksh-debuginfo-20120801-10.el6.ppc64.rpm	SHA-256: 22d72e5321ba6a692d325d358e8883f15aed90e9e25adf4722483033fa9e14b5

Red Hat Enterprise Linux for Scientific Computing 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
x86_64
ksh-20120801-10.el6.x86_64.rpm	SHA-256: 6613de5a86815781c6d468c89ceab873a3f844ae168e6ae79b9b685c0c620925
ksh-debuginfo-20120801-10.el6.x86_64.rpm	SHA-256: 2e64a178617b6dafcb9d1e4faf6ce0e1de234570d3ad2ee089b04282c54fc266

Red Hat Enterprise Linux Server from RHUI 6

SRPM
ksh-20120801-10.el6.src.rpm	SHA-256: 063b7ec17b4edf9be9d36d002bdd1f72771f08983f1efe30e688402f4e69d610
x86_64
ksh-20120801-10.el6.x86_64.rpm	SHA-256: 6613de5a86815781c6d468c89ceab873a3f844ae168e6ae79b9b685c0c620925
ksh-debuginfo-20120801-10.el6.x86_64.rpm	SHA-256: 2e64a178617b6dafcb9d1e4faf6ce0e1de234570d3ad2ee089b04282c54fc266
i386
ksh-20120801-10.el6.i686.rpm	SHA-256: 79ca957c34b46e0e97f8b96c40526419e1cdaaed9fadd1c73c317a594db72e27
ksh-debuginfo-20120801-10.el6.i686.rpm	SHA-256: d620eafe0ead4dbb322b3c67fcbc1465997d620bac55aa26b5fdce31bd367f3f