RHSA-2009:1550: Important: kernel security and bug fix update

First published: Tue Nov 03 2009(Updated: )

The kernel packages contain the Linux kernel, the core of any Linux operating system. Security fixes: <li> when fput() was called to close a socket, the __scm_destroy() function in</li> the Linux kernel could make indirect recursive calls to itself. This could, potentially, lead to a denial of service issue. (CVE-2008-5029, Important) <li> the sendmsg() function in the Linux kernel did not block during UNIX</li> socket garbage collection. This could, potentially, lead to a local denial of service. (CVE-2008-5300, Important) <li> the exit_notify() function in the Linux kernel did not properly reset the</li> exit signal if a process executed a set user ID (setuid) application before exiting. This could allow a local, unprivileged user to elevate their privileges. (CVE-2009-1337, Important) <li> a flaw was found in the Intel PRO/1000 network driver in the Linux</li> 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 or code execution. (CVE-2009-1385, Important) <li> the ADDR_COMPAT_LAYOUT and MMAP_PAGE_ZERO flags were not cleared when a</li> setuid or setgid program was executed. A local, unprivileged user could use this flaw to bypass the mmap_min_addr protection mechanism and perform a NULL pointer dereference attack, or bypass the Address Space Layout Randomization (ASLR) security feature. (CVE-2009-1895, Important) <li> it was discovered that, when executing a new process, the clear_child_tid</li> pointer in the Linux kernel is not cleared. If this pointer points to a writable portion of the memory of the new program, the kernel could corrupt four bytes of memory, possibly leading to a local denial of service or privilege escalation. (CVE-2009-2848, Important) <li> missing initialization flaws were found in getname() implementations in</li> the IrDA sockets, AppleTalk DDP protocol, NET/ROM protocol, and ROSE protocol implementations in the Linux kernel. Certain data structures in these getname() implementations were not initialized properly before being copied to user-space. These flaws could lead to an information leak. (CVE-2009-3002, Important) <li> a NULL pointer dereference flaw was found in each of the following</li> functions in the Linux kernel: pipe_read_open(), pipe_write_open(), and pipe_rdwr_open(). When the mutex lock is not held, the i_pipe pointer could be released by other processes before it is used to update the pipe's reader and writer counters. This could lead to a local denial of service or privilege escalation. (CVE-2009-3547, Important) Bug fixes: <li> this update adds the mmap_min_addr tunable and restriction checks to help</li> prevent unprivileged users from creating new memory mappings below the minimum address. This can help prevent the exploitation of NULL pointer dereference bugs. Note that mmap_min_addr is set to zero (disabled) by default for backwards compatibility. (BZ#512642) <li> a bridge reference count problem in IPv6 has been fixed. (BZ#457010)</li> <li> enforce null-termination of user-supplied arguments to setsockopt().</li> (BZ#505514) <li> the gcc flag "-fno-delete-null-pointer-checks" was added to the kernel</li> build options. This prevents gcc from optimizing out NULL pointer checks after the first use of a pointer. NULL pointer bugs are often exploited by attackers. Keeping these checks is a safety measure. (BZ#511185) <li> a check has been added to the IPv4 code to make sure that rt is not NULL,</li> to help prevent future bugs in functions that call ip_append_data() from being exploitable. (BZ#520300) Users should upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.

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RHSA-2009:1550: Important: kernel security and bug fix update

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