The kernel packages contain the Linux kernel, the core of any Linux operating system.
These updated packages fix the following security issues:
a flaw was found in the Intel PRO/1000 network driver in the Linux kernel. Frames with sizes near the MTU of an interface may be split across multiple hardware receive descriptors. Receipt of such a frame could leak through a validation check, leading to a corruption of the length check. A remote attacker could use this flaw to send a specially-crafted packet that would cause a denial of service. (CVE-2009-1385, Important)
the Linux kernel Network File System daemon (nfsd) implementation did not drop the CAP_MKNOD capability when handling requests from local, unprivileged users. This flaw could possibly lead to an information leak or privilege escalation. (CVE-2009-1072, Moderate)
Frank Filz reported the NFSv4 client was missing a file permission check for the execute bit in some situations. This could allow local, unprivileged users to run non-executable files on NFSv4 mounted file systems. (CVE-2009-1630, Moderate)
a missing check was found in the hypervisor_callback() function in the Linux kernel provided by the kernel-xen package. This could cause a denial of service of a 32-bit guest if an application running in that guest accesses a certain memory location in the kernel. (CVE-2009-1758, Moderate)
a flaw was found in the AGPGART driver. The agp_generic_alloc_page() and agp_generic_alloc_pages() functions did not zero out the memory pages they allocate, which may later be available to user-space processes. This flaw could possibly lead to an information leak. (CVE-2009-1192, Low)
These updated packages also fix the following bugs:
"/proc/[pid]/maps" and "/proc/[pid]/smaps" can only be read by processes able to use the ptrace() call on a given process; however, certain information from "/proc/[pid]/stat" and "/proc/[pid]/wchan" could be used to reconstruct memory maps, making it possible to bypass the Address Space Layout Randomization (ASLR) security feature. This update addresses this issue. (BZ#499549)
in some situations, the link count was not decreased when renaming unused files on NFS mounted file systems. This may have resulted in poor performance. With this update, the link count is decreased in these situations, the same as is done for other file operations, such as unlink and rmdir. (BZ#501802)
tcp_ack() cleared the probes_out variable even if there were outstanding packets. When low TCP keepalive intervals were used, this bug may have caused problems, such as connections terminating, when using remote tools such as rsh and rlogin. (BZ#501754)
off-by-one errors in the time normalization code could have caused clock_gettime() to return one billion nanoseconds, rather than adding an extra second. This bug could have caused the name service cache daemon (nscd) to consume excessive CPU resources. (BZ#501800)
a system panic could occur when one thread read "/proc/bus/input/devices" while another was removing a device. With this update, a mutex has been added to protect the input_dev_list and input_handler_list variables, which resolves this issue. (BZ#501804)
using netdump may have caused a kernel deadlock on some systems. (BZ#504565)
the file system mask, which lists capabilities for users with a file system user ID (fsuid) of 0, was missing the CAP_MKNOD and CAP_LINUX_IMMUTABLE capabilities. This could, potentially, allow users with an fsuid other than 0 to perform actions on some file system types that would otherwise be prevented. This update adds these capabilities. (BZ#497269)
All Red Hat Enterprise Linux 4 users should upgrade to these updated packages, which contain backported patches to resolve these issues. Note: The system must be rebooted for this update to take effect.