| Description: | The do_shmat function in ipc/shm.c in the Linux kernel through 4.9.12 does not restrict the address calculated by a certain rounding operation, which allows local users to map page zero, and consequently bypass a protection mechanism that exists for the mmap system call, by making crafted shmget and shmat system calls in a privileged context. Gareth Evans discovered that the shm IPC subsystem in the Linux kernel did not properly restrict mapping page zero. A local privileged attacker could use this to execute arbitrary code.
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