(RHSA-2004:402) libpng security update

The libpng package contains a library of functions for creating and
manipulating PNG (Portable Network Graphics) image format files.

During a source code audit, Chris Evans discovered several buffer overflows
in libpng. An attacker could create a carefully crafted PNG file in such a
way that it would cause an application linked with libpng to execute
arbitrary code when the file was opened by a victim. The Common
Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name
CAN-2004-0597 to these issues.

In addition, this audit discovered a potential NULL pointer dereference in
libpng (CAN-2004-0598) and several integer overflow issues (CAN-2004-0599).
An attacker could create a carefully crafted PNG file in such a way that
it would cause an application linked with libpng to crash when the file was
opened by the victim.

Red Hat would like to thank Chris Evans for discovering these issues.

For users of Red Hat Enterprise Linux 2.1 these patches also include a more
complete fix for the out of bounds memory access flaw (CAN-2002-1363).

All users are advised to update to the updated libpng packages which
contain backported security patches and are not vulnerable to these issues.