Updated kernel packages are now available fixing several security vulnerabilities. [Updated 28 August 2003] Added CAN-2003-0699 and CAN-2003-0700 to the list of security issues that are fixed by this advisory (there are no changes to the packages themselves).
The Linux kernel handles the basic functions of the operating system. Several security issues have been discovered affecting the Linux kernel: CAN-2003-0461: /proc/tty/driver/serial reveals the exact character counts for serial links. This could be used by a local attacker to infer password lengths and inter-keystroke timings during password entry. CAN-2003-0462: Paul Starzetz discovered a file read race condition existing in the execve() system call, which could cause a local crash. CAN-2003-0464: A recent change in the RPC code set the reuse flag on newly-created sockets. Olaf Kirch noticed that his could allow normal users to bind to UDP ports used for services such as nfsd. CAN-2003-0476: The execve system call in Linux 2.4.x records the file descriptor of the executable process in the file table of the calling process, allowing local users to gain read access to restricted file descriptors. CAN-2003-0501: The /proc filesystem in Linux allows local users to obtain sensitive information by opening various entries in /proc/self before executing a setuid program. This causes the program to fail to change the ownership and permissions of already opened entries. CAN-2003-0550: The STP protocol is known to have no security, which could allow attackers to alter the bridge topology. STP is now turned off by default. CAN-2003-0551: STP input processing was lax in its length checking, which could lead to a denial of service. CAN-2003-0552: Jerry Kreuscher discovered that the Forwarding table could be spoofed by sending forged packets with bogus source addresses the same as the local host. CAN-2003-0699: The C-Media PCI sound driver in kernel versions prior to 2.4.21 does not use the get_user function to access userspace, which crosses security boundaries and may facilitate the exploitation of vulnerabilities. CAN-2003-0700: The C-Media PCI sound driver in kernel versions prior to 2.4.22 accesses userspace without using the get_user function, which is a potential security hole (NOTE: this issue is distinct from that described in CAN-2003-0699). All users are advised to upgrade to these errata packages, which contain backported security patches correcting these vulnerabilities. Important: If you use Red Hat Linux 7.1, you must have installed quota-3.06-9.71 from RHSA-2003-187, and if you use Red Hat Linux 7.2 or 7.3, you must have installed quota-3.06-9.7 from RHSA-2003-187.