glibc security update

Updated glibc packages that address several bugs are now available.

This update has been rated as having low security impact by the Red Hat
Security Response Team.

The GNU libc packages (known as glibc) contain the standard C libraries
used by applications.

It was discovered that the use of LD_DEBUG, LD_SHOW_AUXV, and
LD_DYNAMIC_WEAK were not restricted for a setuid program. A local user
could utilize this flaw to gain information, such as the list of symbols
used by the program. The Common Vulnerabilities and Exposures project
(cve.mitre.org) has assigned the name CAN-2004-1453 to this issue.

This erratum addresses the following bugs in the GNU C Library:

- fix stack alignment in IA-32 clone
- fix double free in globfree
- fix fnmatch to avoid jumping based on unitialized memory read
- fix fseekpos after ungetc
- fix TZ env var handling if the variable ends with + or -
- avoid depending on values read from unitialized memory in strtold
on certain architectures
- fix mapping alignment computation in dl-load
- fix i486+ strncat inline assembly
- make gethostid/sethostid work on bi-arch platforms
- fix ppc64 getcontext/swapcontext
- fix pthread_exit if called after pthread_create, but before the created
thread actually started
- fix return values for tgamma (+-0)
- fix handling of very long lines in /etc/hosts
- avoid page aliasing of thread stacks on AMD64
- avoid busy loop in malloc if concurrent with fork
- allow putenv and setenv in shared library constructors
- fix restoring of CCR in swapcontext and getcontext on ppc64
- avoid using sigaction (SIGPIPE, ...) in syslog implementation

All users of glibc should upgrade to these updated packages, which resolve
these issues.

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied. Use Red Hat
Network to download and update your packages. To launch the Red Hat
Update Agent, use the following command:

up2date

For information on how to install packages manually, refer to the
following Web page for the System Administration or Customization
guide specific to your system:

http://www.redhat.com/docs/manuals/enterprise/

135125 - telnet: 0: Name or service not known
138439 - re_compile_pattern segfault
140378 - [RHEL3] glibc behavior with long lines in /etc/hosts
142617 - [RHEL3] libc's getXXent and getXXbyYY are inefficient for large groups
143279 - x86_64 ecvt() returns "inf" for valid denormalized doubles
146210 - zdump -v GMT segfaults in x86_64
146402 - CAN-2004-1453 Information leak with LD_DEBUG
146710 - pthread_getspecific gets non-NULL value for new key
147478 - nscd fails with big group in ldap
149205 - malloc: top chunk is corrupt w/ MALLOC_CHECK_=3

https://www.redhat.com/security/data/cve/CVE-2004-1453.html

glibc, LD_DEBUG