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Vigil@nce - Linux kernel: NULL pointer dereference via pmd_none_or_trans_huge_or_clear_bad
March 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
A local attacker can force a NULL pointer to be dereferenced in
the pmd_none_or_trans_huge_or_clear_bad() function of the Linux
kernel, in order to trigger a denial of service.
Impacted products: Linux, RHEL
Severity: 1/4
Creation date: 17/03/2015
DESCRIPTION OF THE VULNERABILITY
The madvise() system call is used by developers to indicate to the
kernel how to manage the memory.
The MADV_WILLNEED parameter indicates that the program will soon
need to access to the memory. However, the Page Middle Directory
pmd_none_or_trans_huge_or_clear_bad() function does not check if a
pointer is NULL, before using it.
A local attacker can therefore force a NULL pointer to be
dereferenced in the pmd_none_or_trans_huge_or_clear_bad() function
of the Linux kernel, in order to trigger a denial of service.
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