tree d0d1dad3dc8d70009f5569727eb97d5e19bf983e
parent 4c696abed9be72e8560d58bc9c26417bb774c6e6
author Charlie Mooney <charliemooney@chromium.org> 1396893208 -0700
committer Charlie Mooney <charliemooney@chromium.org> 1397230918 -0700

Close the security hole in try_touch_experiments

There was an exploit in try_touch_experiments where a malicious string
could be input that when converted from hex to ascii would produce a
property name that could escape out and run whatever it would like on
the command line when the program shelled out to alter the X properties.

This patch attempts to fix this by two approaches.

First: Input Validation.  There is only a small subset of characters
that are legal in inputs.  The program now does a more thorough job
filtering and will reject any input that contains illegal characters
even after decoding the string from hex->ascii.

Second: No shelling out.  The X properties used to be changed using a
command line tool called xinput.  To prevent this being exploited, I
have converted the program to do it manually.  Now when property.cc
wants to alter a value, it actually connects to the X server itself and
changes the properties directly.

BUG=chromium:351857
TEST=manually tested on Pit and Peppy.  It compiled and was able to run
experiments on each successfully.  Known malicious input was
unsuccessful.

Change-Id: Ie4f0dafbbce2862feb98ba584ab8c16f54a5ea7c
Signed-off-by: Charlie Mooney <charliemooney@chromium.org>