| Description: | fs/namespace.c in the Linux kernel through 3.16.1 does not properly restrict clearing MNT_NODEV, MNT_NOSUID, and MNT_NOEXEC and changing MNT_ATIME_MASK during a remount of a bind mount, which allows local users to gain privileges, interfere with backups and auditing on systems that had atime enabled, or cause a denial of service (excessive filesystem updating) on systems that had atime disabled via a "mount -o remount" command within a user namespace. Eric W. Biederman discovered a flaw with the mediation of mount flags in the Linux kernel's user namespace subsystem. An unprivileged user could exploit this flaw to by-pass mount restrictions, and potentially gain administrative privileges.
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