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Vigil@nce - Linux kernel: denial of service via Punch Hole
June 2014 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
A local attacker can use a mmap() during a Punch Hole by the Linux
kernel, in order to trigger a denial of service.
Impacted products: Linux
Severity: 1/4
Creation date: 18/06/2014
DESCRIPTION OF THE VULNERABILITY
A part of an allocated area (XFS, ext4, Btrfs, tmpfs) can be freed
(Punch Hole) with:
madvise(..., MADV_REMOVE);
fallocate(fd, FALLOC_FL_PUNCH_HOLE, ...);
However, if a user has a mmap() surrounding the area to free, the
kernel locks.
A local attacker can therefore use a mmap() during a Punch Hole by
the Linux kernel, in order to trigger a denial of service.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Linux-kernel-denial-of-service-via-Punch-Hole-14912
