Updated libpng packages fix vulnerabilities

Updated libpng packages that fix various buffer overflow vulnerabilities
are available for Red Hat Linux on IBM iSeries and pSeries systems.

The libpng package contains a library of functions for creating and
manipulating PNG (Portable Network Graphics) image format files. PNG
is a bit-mapped graphics format similar to the GIF format.

Versions of libpng prior to 1.0.14 contain a buffer overflow in the
progressive reader when the PNG datastream contains more IDAT data than
indicated by the IHDR chunk. Such deliberately malformed datastreams would
crash applications that are linked to libpng and that use the progressive
reading feature. Mozilla is such an application. (CAN-2002-0728)

Packages within Red Hat Linux, such as Mozilla, make use of the shared
libpng library. Therefore, all users are advised to upgrade to the errata
packages, which contain libpng 1.0.14. Libpng 1.0.14 is not vulnerable to
this issue and contains fixes for other bugs, including a number of memory
leaks and another potential buffer overflow (CAN-2002-0660)

Unpatched versions of libpng 1.2.1 and earlier do not correctly calculate
offsets, which leads to a buffer overflow and the possibility of arbitrary
code execution. This could be exploited by an attacker creating a
carefully crafted PNG file, which could execute arbitrary code when the
victim views it. (CAN-2002-1363)

All users are advised to upgrade to the errata packages containing libpng
1.0.14 with backported patches correcting these vulnerabilities.

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

To update all RPMs for your particular architecture, run:

rpm -Fvh [filenames]

where [filenames] is a list of the RPMs you wish to upgrade. Only those
RPMs which are currently installed will be updated. Those RPMs which are
not installed but included in the list will not be updated. Note that you
can also use wildcards (*.rpm) if your current directory *only* contains the
desired RPMs.

Please note that this update is also available via Red Hat Network. Many
people find this an easier way to apply updates. To use Red Hat Network,
launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate
RPMs being upgraded on your system.

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-0660
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-0728
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-1363

buffer, libpng, overflow