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Security Advisory Low: bash security, bug fix, and enhancement update

Advisory: RHSA-2011:1073-1
Type: Security Advisory
Severity: Low
Issued on: 2011-07-21
Last updated on: 2011-07-21
Affected Products: Red Hat Enterprise Linux (v. 5 server)
Red Hat Enterprise Linux Desktop (v. 5 client)
CVEs (cve.mitre.org): CVE-2008-5374

Details

An updated bash package that fixes one security issue, several bugs, and
adds one enhancement is now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having low
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

Bash is the default shell for Red Hat Enterprise Linux.

It was found that certain scripts bundled with the Bash documentation
created temporary files in an insecure way. A malicious, local user could
use this flaw to conduct a symbolic link attack, allowing them to overwrite
the contents of arbitrary files accessible to the victim running the
scripts. (CVE-2008-5374)

This update fixes the following bugs:

* When using the source builtin at location ".", occasionally, bash
opted to preserve internal consistency and abort scripts. This caused
bash to abort scripts that assigned values to read-only variables.
This is now fixed to ensure that such scripts are now executed as
written and not aborted. (BZ#448508)

* When the tab key was pressed for auto-completion options for the typed
text, the cursor moved to an unexpected position on a previous line if
the prompt contained characters that cannot be viewed and a "\]". This
is now fixed to retain the cursor at the expected position at the end of
the target line after autocomplete options correctly display. (BZ#463880)

* Bash attempted to interpret the NOBITS .dynamic section of the ELF
header. This resulted in a "^D: bad ELF interpreter: No such
file or directory" message. This is fixed to ensure that the invalid
"^D" does not appear in the error message. (BZ#484809)

* The $RANDOM variable in Bash carried over values from a previous
execution for later jobs. This is fixed and the $RANDOM variable
generates a new random number for each use. (BZ#492908)

* When Bash ran a shell script with an embedded null character, bash's
source builtin parsed the script incorrectly. This is fixed and
bash's source builtin correctly parses shell script null characters.
(BZ#503701)

* The bash manual page for "trap" did not mention that signals ignored upon
entry cannot be listed later. The manual page was updated for this update
and now specifically notes that "Signals ignored upon entry to the shell
cannot be trapped, reset or listed". (BZ#504904)

* Bash's readline incorrectly displayed additional text when resizing
the terminal window when text spanned more than one line, which caused
incorrect display output. This is now fixed to ensure that text in more
than one line in a resized window displays as expected. (BZ#525474)

* Previously, bash incorrectly displayed "Broken pipe" messages for
builtins like "echo" and "printf" when output did not succeed due to
EPIPE. This is fixed to ensure that the unnecessary "Broken pipe"
messages no longer display. (BZ#546529)

* Inserts with the repeat function were not possible after a deletion in
vi-mode. This has been corrected and, with this update, the repeat function
works as expected after a deletion. (BZ#575076)

* In some situations, bash incorrectly appended "/" to files instead of
just directories during tab-completion, causing incorrect
auto-completions. This is fixed and auto-complete appends "/" only to
directories. (BZ#583919)

* Bash had a memory leak in the "read" builtin when the number of fields
being read was not equal to the number of variables passed as arguments,
causing a shell script crash. This is fixed to prevent a memory leak and
shell script crash. (BZ#618393)

* /usr/share/doc/bash-3.2/loadables in the bash package contained source
files which would not build due to missing C header files. With this
update, the unusable (and unbuildable) source files were removed from the
package. (BZ#663656)

This update also adds the following enhancement:

* The system-wide "/etc/bash.bash_logout" bash logout file is now enabled.
This allows administrators to write system-wide logout actions for all
users. (BZ#592979)

Users of bash are advised to upgrade to this updated package, which
contains backported patches to resolve these issues and add this
enhancement.


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

Updated packages

Red Hat Enterprise Linux (v. 5 server)

SRPMS:
bash-3.2-32.el5.src.rpm
File outdated by:  RHBA-2013:1040
    MD5: 62259eb0faa107f8c799a90592678b63
SHA-256: e7aebfb0fba14d52db7f7703f5275b4ca5e43e564a50818cc6883c38bfc6ca74
 
IA-32:
bash-3.2-32.el5.i386.rpm
File outdated by:  RHBA-2013:1040
    MD5: 74b9b1321fd4c27a2e51d012fe54b508
SHA-256: 300aa2813b9ca1f9c7a2921892f3fab355187a43432f0b755b4efd0ebdcd92f8
 
IA-64:
bash-3.2-32.el5.i386.rpm
File outdated by:  RHBA-2013:1040
    MD5: 74b9b1321fd4c27a2e51d012fe54b508
SHA-256: 300aa2813b9ca1f9c7a2921892f3fab355187a43432f0b755b4efd0ebdcd92f8
bash-3.2-32.el5.ia64.rpm
File outdated by:  RHBA-2013:1040
    MD5: beedb6c6f2cbea060ea286f5ecaeffff
SHA-256: 7808f2d8f4adebc73d5fc364c7acddbd0e96abf55df521ac3af37e00352a3f28
 
PPC:
bash-3.2-32.el5.ppc.rpm
File outdated by:  RHBA-2013:1040
    MD5: 3502d576976e52e15dfe4f9b3acb2641
SHA-256: 75edefa8500b926823133fd018edc1c88851aea6aa677ca12646a2f812a24d61
 
s390x:
bash-3.2-32.el5.s390x.rpm
File outdated by:  RHBA-2013:1040
    MD5: 4a1a509511f833c70e5c3c47c7a8184d
SHA-256: c28b2fa01df2e8c341f540946ad5868386d19a9d64187314cf6fda2c16405857
 
x86_64:
bash-3.2-32.el5.x86_64.rpm
File outdated by:  RHBA-2013:1040
    MD5: 4e65d24be718583ca367d501ae49f2f5
SHA-256: a73a67da611dd982274c071f0b6f733fdcfdc63911c8066fb5dd0f02a738c395
 
Red Hat Enterprise Linux Desktop (v. 5 client)

SRPMS:
bash-3.2-32.el5.src.rpm
File outdated by:  RHBA-2013:1040
    MD5: 62259eb0faa107f8c799a90592678b63
SHA-256: e7aebfb0fba14d52db7f7703f5275b4ca5e43e564a50818cc6883c38bfc6ca74
 
IA-32:
bash-3.2-32.el5.i386.rpm
File outdated by:  RHBA-2013:1040
    MD5: 74b9b1321fd4c27a2e51d012fe54b508
SHA-256: 300aa2813b9ca1f9c7a2921892f3fab355187a43432f0b755b4efd0ebdcd92f8
 
x86_64:
bash-3.2-32.el5.x86_64.rpm
File outdated by:  RHBA-2013:1040
    MD5: 4e65d24be718583ca367d501ae49f2f5
SHA-256: a73a67da611dd982274c071f0b6f733fdcfdc63911c8066fb5dd0f02a738c395
 
(The unlinked packages above are only available from the Red Hat Network)

Bugs fixed (see bugzilla for more information)

448508 - Parsing of {} broken; breaks startup scripts
463880 - bash completion in UTF8 locale has cursor positioning errors with long $PS1
475474 - CVE-2008-5374 bash: Insecure temporary file use in aliasconv.sh, aliasconv.bash, cshtobash (symlink attack)
484809 - [RHEL5] bash includes Control-D in "bad ELF interpreter" message
492908 - $RANDOM value remains the same
503701 - Cannot process scripts beyond an embedded NULL character when running in 'source' mode
504904 - trap -p not displaying ignored signal when run from child bash
525474 - bash/readline not detecting window resize properly
583919 - tab-completion appends slash to non-directories
592979 - system global bash.bash_logout is diabled in config-top.h
618393 - memory leak in bash reading files
663656 - Unusable loadables in /doc


References



These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from:
https://www.redhat.com/security/team/key/#package

The Red Hat security contact is secalert@redhat.com. More contact details at http://www.redhat.com/security/team/contact/