mirror of
https://gitlab.freedesktop.org/libinput/libinput.git
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2a8b8fde90
This fixes a format string vulnerabilty.
evdev_log_message() composes a format string consisting of a fixed
prefix (including the rendered device name) and the passed-in format
buffer. This format string is then passed with the arguments to the
actual log handler, which usually and eventually ends up being printf.
If the device name contains a printf-style format directive, these ended
up in the format string and thus get interpreted correctly, e.g. for a
device "Foo%sBar" the log message vs printf invocation ends up being:
evdev_log_message(device, "some message %s", "some argument");
printf("event9 - Foo%sBar: some message %s", "some argument");
This can enable an attacker to execute malicious code with the
privileges of the process using libinput.
To exploit this, an attacker needs to be able to create a kernel device
with a malicious name, e.g. through /dev/uinput or a Bluetooth device.
To fix this, convert any potential format directives in the device name
by duplicating percentages.
Pre-rendering the device to avoid the issue altogether would be nicer
but the current log level hooks do not easily allow for this. The device
name is the only user-controlled part of the format string.
A second potential issue is the sysname of the device which is also
sanitized.
This issue was found by Albin Eldstål-Ahrens and Benjamin Svensson from
Assured AB, and independently by Lukas Lamster.
Fixes #752
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit a423d7d326)
56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
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/*
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* Copyright © 2013 Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#include "config.h"
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#include "litest.h"
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#include "litest-int.h"
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static struct input_id input_id = {
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.bustype = 0x3,
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.vendor = 0x0123,
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.product = 0x0456,
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};
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static int events[] = {
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EV_KEY, BTN_LEFT,
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EV_KEY, BTN_RIGHT,
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EV_KEY, BTN_MIDDLE,
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EV_REL, REL_X,
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EV_REL, REL_Y,
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EV_REL, REL_WHEEL,
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EV_REL, REL_WHEEL_HI_RES,
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-1 , -1,
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};
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TEST_DEVICE("mouse-format-string",
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.type = LITEST_MOUSE_FORMAT_STRING,
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.features = LITEST_RELATIVE | LITEST_BUTTON | LITEST_WHEEL,
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.interface = NULL,
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.name = "Evil %s %d %x Mouse %p %",
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.id = &input_id,
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.absinfo = NULL,
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.events = events,
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)
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