Files
Dmitry Torokhov 7f0b4c25fd Input: reject parent overrides on managed input devices
When an input device is allocated with devm_input_allocate_device(), the
owner struct device is set as dev->dev.parent and holds the
devm_input_device_release resource. Later, input_register_device()
attaches the devm_input_device_unregister resource to dev->dev.parent.

Clearing or overriding dev->dev.parent before registration splits devres
ownership across different devices, which breaks managed lifetime
assumptions.

Verify via devres_find() that dev->dev.parent is non-NULL and still
holds the matching devm_input_device_release entry before registering a
managed input device, rejecting registration with -EINVAL otherwise.

Also add KUnit test coverage in input_test.c verifying that reparented
and NULL-parent managed input devices are rejected while preserving the
owner parent succeeds.

Assisted-by: LLM
Link: https://patch.msgid.link/asmCc1VxVPLIMgY6@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2026-10-14 10:25:00 -07:00

218 lines
6.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* KUnit test for the input core.
*
* Copyright (c) 2023 Red Hat Inc
*/
#include <linux/delay.h>
#include <linux/input.h>
#include <kunit/device.h>
#include <kunit/test.h>
#define POLL_INTERVAL 100
static int input_test_init(struct kunit *test)
{
struct input_dev *input_dev;
int ret;
input_dev = input_allocate_device();
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, input_dev);
input_dev->name = "Test input device";
input_dev->id.bustype = BUS_VIRTUAL;
input_dev->id.vendor = 1;
input_dev->id.product = 1;
input_dev->id.version = 1;
input_set_capability(input_dev, EV_KEY, BTN_LEFT);
input_set_capability(input_dev, EV_KEY, BTN_RIGHT);
ret = input_register_device(input_dev);
if (ret) {
input_free_device(input_dev);
KUNIT_FAIL_AND_ABORT(test, "Register device failed: %d", ret);
}
test->priv = input_dev;
return 0;
}
static void input_test_exit(struct kunit *test)
{
struct input_dev *input_dev = test->priv;
if (input_dev)
input_unregister_device(input_dev);
}
static void input_test_poll(struct input_dev *input) { }
static void input_test_polling(struct kunit *test)
{
struct input_dev *input_dev = test->priv;
/* Must fail because a poll handler has not been set-up yet */
KUNIT_ASSERT_EQ(test, input_get_poll_interval(input_dev), -EINVAL);
KUNIT_ASSERT_EQ(test, input_setup_polling(input_dev, input_test_poll), 0);
input_set_poll_interval(input_dev, POLL_INTERVAL);
/* Must succeed because poll handler was set-up and poll interval set */
KUNIT_ASSERT_EQ(test, input_get_poll_interval(input_dev), POLL_INTERVAL);
}
static void input_test_timestamp(struct kunit *test)
{
const ktime_t invalid_timestamp = ktime_set(0, 0);
struct input_dev *input_dev = test->priv;
ktime_t *timestamp, time;
timestamp = input_get_timestamp(input_dev);
time = timestamp[INPUT_CLK_MONO];
/* The returned timestamp must always be valid */
KUNIT_ASSERT_EQ(test, ktime_compare(time, invalid_timestamp), 1);
time = ktime_get();
input_set_timestamp(input_dev, time);
timestamp = input_get_timestamp(input_dev);
/* The timestamp must be the same than set before */
KUNIT_ASSERT_EQ(test, ktime_compare(timestamp[INPUT_CLK_MONO], time), 0);
}
static void input_test_match_device_id(struct kunit *test)
{
struct input_dev *input_dev = test->priv;
struct input_device_id id = { 0 };
/*
* Must match when the input device bus, vendor, product, version
* and events capable of handling are the same and fail to match
* otherwise.
*/
id.flags = INPUT_DEVICE_ID_MATCH_BUS;
id.bustype = BUS_VIRTUAL;
KUNIT_ASSERT_TRUE(test, input_match_device_id(input_dev, &id));
id.bustype = BUS_I2C;
KUNIT_ASSERT_FALSE(test, input_match_device_id(input_dev, &id));
id.flags = INPUT_DEVICE_ID_MATCH_VENDOR;
id.vendor = 1;
KUNIT_ASSERT_TRUE(test, input_match_device_id(input_dev, &id));
id.vendor = 2;
KUNIT_ASSERT_FALSE(test, input_match_device_id(input_dev, &id));
id.flags = INPUT_DEVICE_ID_MATCH_PRODUCT;
id.product = 1;
KUNIT_ASSERT_TRUE(test, input_match_device_id(input_dev, &id));
id.product = 2;
KUNIT_ASSERT_FALSE(test, input_match_device_id(input_dev, &id));
id.flags = INPUT_DEVICE_ID_MATCH_VERSION;
id.version = 1;
KUNIT_ASSERT_TRUE(test, input_match_device_id(input_dev, &id));
id.version = 2;
KUNIT_ASSERT_FALSE(test, input_match_device_id(input_dev, &id));
id.flags = INPUT_DEVICE_ID_MATCH_EVBIT;
__set_bit(EV_KEY, id.evbit);
KUNIT_ASSERT_TRUE(test, input_match_device_id(input_dev, &id));
__set_bit(EV_ABS, id.evbit);
KUNIT_ASSERT_FALSE(test, input_match_device_id(input_dev, &id));
}
static void input_test_grab(struct kunit *test)
{
struct input_dev *input_dev = test->priv;
struct input_handle test_handle;
struct input_handler handler;
struct input_handle handle;
struct input_device_id id;
int res;
handler.name = "handler";
handler.id_table = &id;
handle.dev = input_get_device(input_dev);
handle.name = dev_name(&input_dev->dev);
handle.handler = &handler;
res = input_grab_device(&handle);
KUNIT_ASSERT_TRUE(test, res == 0);
test_handle.dev = input_get_device(input_dev);
test_handle.name = dev_name(&input_dev->dev);
test_handle.handler = &handler;
res = input_grab_device(&test_handle);
KUNIT_ASSERT_EQ(test, res, -EBUSY);
input_release_device(&handle);
input_put_device(input_dev);
res = input_grab_device(&test_handle);
KUNIT_ASSERT_TRUE(test, res == 0);
input_put_device(input_dev);
}
static void input_test_managed_parent_override(struct kunit *test)
{
struct device *owner, *other_dev;
struct input_dev *input_dev;
owner = kunit_device_register(test, "input-test-owner");
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, owner);
other_dev = kunit_device_register(test, "input-test-other");
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, other_dev);
/* Overriding dev.parent to another device must be rejected */
input_dev = devm_input_allocate_device(owner);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, input_dev);
input_dev->name = "Managed input device (reparented)";
input_dev->dev.parent = other_dev;
KUNIT_EXPECT_EQ(test, input_register_device(input_dev), -EINVAL);
/* Clearing dev.parent to NULL must be rejected */
input_dev = devm_input_allocate_device(owner);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, input_dev);
input_dev->name = "Managed input device (null parent)";
input_dev->dev.parent = NULL;
KUNIT_EXPECT_EQ(test, input_register_device(input_dev), -EINVAL);
/* Preserving original owner as dev.parent succeeds */
input_dev = devm_input_allocate_device(owner);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, input_dev);
input_dev->name = "Managed input device (valid parent)";
KUNIT_EXPECT_EQ(test, input_register_device(input_dev), 0);
}
static struct kunit_case input_tests[] = {
KUNIT_CASE(input_test_polling),
KUNIT_CASE(input_test_timestamp),
KUNIT_CASE(input_test_match_device_id),
KUNIT_CASE(input_test_grab),
KUNIT_CASE(input_test_managed_parent_override),
{ /* sentinel */ }
};
static struct kunit_suite input_test_suite = {
.name = "input_core",
.init = input_test_init,
.exit = input_test_exit,
.test_cases = input_tests,
};
kunit_test_suite(input_test_suite);
MODULE_AUTHOR("Javier Martinez Canillas <javierm@redhat.com>");
MODULE_DESCRIPTION("KUnit test for the input core");
MODULE_LICENSE("GPL");