The Linux kernel handles the basic functions of the operating system.
Paul Starzetz discovered flaws in the Linux kernel when handling file offset pointers. These consist of invalid conversions of 64 to 32-bit file offset pointers and possible race conditions. A local unprivileged user could make use of these flaws to access large portions of kernel memory. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2004-0415 to this issue.
These packages contain a patch written by Al Viro to correct these flaws. Red Hat would like to thank iSEC Security Research for disclosing this issue and a number of vendor-sec participants for reviewing and working on the patch to this issue.
In addition, these packages correct two minor issues:
An bug in the e1000 network driver. This bug could be used by local users to leak small amounts of kernel memory (CAN-2004-0535).
Inappropriate permissions on /proc/scsi/qla2300/HbaApiNode (CAN-2004-0587).
All Red Hat Enterprise Linux 2.1 users are advised to upgrade their kernels to these erratum packages which contain backported patches to correct these issues.