Some vulnerabilities have been reported in the Linux kernel, which can be exploited by malicious, local users to cause a DoS (Denial of Service) and gain knowledge of potentially sensitive information.

1) An error in the "nfs_get_user_pages()" function due to insufficient checks on the return value returned by the "get_user_pages()" function can be exploited to cause a local DoS by performing an O_DIRECT write to an NFS file where the user buffer starts with a valid mapped page, but also contains an unmapped page.

2) Missing checks for bad elf entry addresses can be exploited to cause an endless recursive fault on Intel systems, which results in a local DoS.

3) The "sys_mbind()" function in "/mm/mempolicy.c" does not sanity check its arguments before passing it to the "get_nodes()" function. This can potentially be exploited to cause a local DoS.

An error in the XFS "ftruncate()" function, which may expose stale data off disk to users, has also been reported.

4) A race condition in the "sys_add_key()", "sys_request_key()", and "keyctl()" functions in "/security/keys/keyctl.c" can potentially be exploited by local users to either crash the kernel or read random parts of kernel memory by modifying the length of string arguments after the kernel has determined their length, but before the kernel copied them into kernel memory.

The vulnerability has been reported in versions prior to 2.6.15.4.

Solution
Update to version 2.6.15.5.
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Reported by vendor.

Changelog
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Original Advisory
http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.15.5
http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.15.4
http://www.kernel.org/git/?p=linux/kernel/git/stable/linux-2.6.15.y.git;a=commit;h=330d460744b92d00d5114079fcfc8e547d7ac143
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=636f13c174dd7c84a437d3c3e8fa66f03f7fda63

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