Description: | arch/x86/kernel/tls.c in the Thread Local Storage (TLS) implementation in the Linux kernel through 3.18.1 allows local users to bypass the espfix protection mechanism, and consequently makes it easier for local users to bypass the ASLR protection mechanism, via a crafted application that makes a set_thread_area system call and later reads a 16-bit value. Andy Lutomirski discovered an information leak in the Linux kernel's Thread Local Storage (TLS) implementation allowing users to bypass the espfix to obtain information that could be used to bypass the Address Space Layout Randomization (ASLR) protection mechanism. A local user could exploit this flaw to obtain potentially sensitive information from kernel memory.
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