serial: omap: Prevent DoS using unprivileged ioctl(TIOCSRS485)

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commit 308bbc9ab8 upstream.

The omap-serial driver emulates RS485 delays using software timers,
but neglects to clamp the input values from the unprivileged
ioctl(TIOCSRS485). Because the software implementation busy-waits,
malicious userspace could stall the cpu for ~49 days.

Clamp the input values to < 100ms.

Fixes: 4a0ac0f55b ("OMAP: add RS485 support")
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Peter Hurley 2016-01-12 15:14:46 -08:00 • committed by Greg Kroah-Hartman

parent 76e88140aa

commit 5859b90777

1 changed files with 6 additions and 2 deletions

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drivers/tty/serial/omap-serial.c

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