It was found that a read of n*PAGE_SIZE+1 from /dev/zero
will cause the kernel to panic due to an unhandled exception since it's
not handling the single byte case with a fixup (anything larger than a
single byte will properly fault.)
A local, unprivileged user could use this flaw to crash the system.
Upstream patch proposal:
This issue was discovered by Miloš Prchlík of Red Hat.
This issue does not affect the Linux kernel packages as shipped with Red Hat
Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1163745]
kernel-3.17.3-300.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
kernel-3.17.3-200.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.