We currently lack support for abs-resolution and abs-value parameters
during uinput ABS initialization. Furthermore, our parsers don't allow
growing ABS_CNT values. Therefore, introduce uinput_user_dev2.
User-space is free to write uinput_user_dev2 objects instead of
uinput_user_dev legacy objects now. If the kernel lacks support for it,
our comparison for "count != sizeof(struct uinput_user_dev)" will catch
this and return EINVAL. User-space shall retry with the legacy mode then.
Internally, we transform the legacy object into uinput_user_dev2 and then
handle both the same way.
The new uinput_user_dev2 object has multiple new features:
- abs payload now has "value" and "resolution" parameters as part of the
switch to "struct input_absinfo". We simply copy these over.
- Our parser allows growing ABS_CNT. We automatically detect the payload
size of the caller, thus, calculating the ABS_CNT the program was
compiled with.
- A "version" field to denote the uinput-version used. This is required
to properly support changing "struct input_user_dev2" changes in the
future. Due to the dynamic ABS_CNT support, we cannot simply add new
fields, as we cannot deduce the structure size from the user-space
given size. Thus, we need the "version" field to allow changing the
object and properly detecting it in our write() handler.
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
---
drivers/input/misc/uinput.c | 142 ++++++++++++++++++++++++++++++++------------
include/uapi/linux/uinput.h | 9 +++
2 files changed, 114 insertions(+), 37 deletions(-)
diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index a0a4bba..3cd84d2 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -358,14 +358,16 @@ static int uinput_allocate_device(struct uinput_device *udev)
}
static int uinput_setup_device(struct uinput_device *udev,
- const char __user *buffer, size_t count)
+ struct uinput_user_dev2 *user_dev2,
+ size_t abscnt)
{
- struct uinput_user_dev *user_dev;
struct input_dev *dev;
int i;
int retval;
+ struct input_absinfo *abs;
- if (count != sizeof(struct uinput_user_dev))
+ /* Ensure name is filled in */
+ if (!user_dev2->name[0])
return -EINVAL;
if (!udev->dev) {
@@ -375,37 +377,27 @@ static int uinput_setup_device(struct uinput_device *udev,
}
dev = udev->dev;
-
- user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
- if (IS_ERR(user_dev))
- return PTR_ERR(user_dev);
-
- udev->ff_effects_max = user_dev->ff_effects_max;
-
- /* Ensure name is filled in */
- if (!user_dev->name[0]) {
- retval = -EINVAL;
- goto exit;
- }
+ udev->ff_effects_max = user_dev2->ff_effects_max;
kfree(dev->name);
- dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
+ dev->name = kstrndup(user_dev2->name, UINPUT_MAX_NAME_SIZE,
GFP_KERNEL);
- if (!dev->name) {
- retval = -ENOMEM;
- goto exit;
- }
-
- dev->id.bustype = user_dev->id.bustype;
- dev->id.vendor = user_dev->id.vendor;
- dev->id.product = user_dev->id.product;
- dev->id.version = user_dev->id.version;
+ if (!dev->name)
+ return -ENOMEM;
- for (i = 0; i < ABS_CNT; i++) {
- input_abs_set_max(dev, i, user_dev->absmax[i]);
- input_abs_set_min(dev, i, user_dev->absmin[i]);
- input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
- input_abs_set_flat(dev, i, user_dev->absflat[i]);
+ dev->id.bustype = user_dev2->id.bustype;
+ dev->id.vendor = user_dev2->id.vendor;
+ dev->id.product = user_dev2->id.product;
+ dev->id.version = user_dev2->id.version;
+
+ for (i = 0; i < abscnt; i++) {
+ abs = &user_dev2->abs[i];
+ input_abs_set_val(dev, i, abs->value);
+ input_abs_set_max(dev, i, abs->maximum);
+ input_abs_set_min(dev, i, abs->minimum);
+ input_abs_set_fuzz(dev, i, abs->fuzz);
+ input_abs_set_flat(dev, i, abs->flat);
+ input_abs_set_res(dev, i, abs->resolution);
}
/* check if absmin/absmax/absfuzz/absflat are filled as
@@ -413,7 +405,7 @@ static int uinput_setup_device(struct uinput_device *udev,
if (test_bit(EV_ABS, dev->evbit)) {
retval = uinput_validate_absbits(dev);
if (retval < 0)
- goto exit;
+ return retval;
if (test_bit(ABS_MT_SLOT, dev->absbit)) {
int nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
input_mt_init_slots(dev, nslot, 0);
@@ -423,11 +415,84 @@ static int uinput_setup_device(struct uinput_device *udev,
}
udev->state = UIST_SETUP_COMPLETE;
- retval = count;
+ return 0;
+}
+
+static int uinput_setup_device1(struct uinput_device *udev,
+ const char __user *buffer, size_t count)
+{
+ struct uinput_user_dev *user_dev;
+ struct uinput_user_dev2 *user_dev2;
+ int i;
+ int retval;
+
+ if (count != sizeof(struct uinput_user_dev))
+ return -EINVAL;
+
+ user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
+ if (IS_ERR(user_dev))
+ return PTR_ERR(user_dev);
+
+ user_dev2 = kmalloc(sizeof(*user_dev2), GFP_KERNEL);
+ if (!user_dev2) {
+ kfree(user_dev);
+ return -ENOMEM;
+ }
+
+ user_dev2->version = UINPUT_VERSION;
+ memcpy(user_dev2->name, user_dev->name, UINPUT_MAX_NAME_SIZE);
+ memcpy(&user_dev2->id, &user_dev->id, sizeof(struct input_id));
+ user_dev2->ff_effects_max = user_dev->ff_effects_max;
+
+ for (i = 0; i < ABS_CNT; ++i) {
+ user_dev2->abs[i].value = 0;
+ user_dev2->abs[i].maximum = user_dev->absmax[i];
+ user_dev2->abs[i].minimum = user_dev->absmin[i];
+ user_dev2->abs[i].fuzz = user_dev->absfuzz[i];
+ user_dev2->abs[i].flat = user_dev->absflat[i];
+ user_dev2->abs[i].resolution = 0;
+ }
+
+ retval = uinput_setup_device(udev, user_dev2, ABS_CNT);
- exit:
kfree(user_dev);
- return retval;
+ kfree(user_dev2);
+
+ return retval ? retval : count;
+}
+
+static int uinput_setup_device2(struct uinput_device *udev,
+ const char __user *buffer, size_t count)
+{
+ struct uinput_user_dev2 *user_dev2;
+ int retval;
+ size_t off, abscnt, max;
+
+ /* The first revision of "uinput_user_dev2" is bigger than
+ * "uinput_user_dev" and growing. Disallow any smaller payloads. */
+ if (count <= sizeof(struct uinput_user_dev))
+ return -EINVAL;
+
+ /* rough check to avoid huge kernel space allocations */
+ max = ABS_CNT * sizeof(*user_dev2->abs) + sizeof(*user_dev2);
+ if (count > max)
+ return -EINVAL;
+
+ user_dev2 = memdup_user(buffer, count);
+ if (IS_ERR(user_dev2))
+ return PTR_ERR(user_dev2);
+
+ if (user_dev2->version > UINPUT_VERSION) {
+ retval = -EINVAL;
+ } else {
+ off = offsetof(struct uinput_user_dev2, abs);
+ abscnt = (count - off) / sizeof(*user_dev2->abs);
+ retval = uinput_setup_device(udev, user_dev2, abscnt);
+ }
+
+ kfree(user_dev2);
+
+ return retval ? retval : count;
}
static ssize_t uinput_inject_event(struct uinput_device *udev,
@@ -459,9 +524,12 @@ static ssize_t uinput_write(struct file *file, const char __user *buffer,
if (retval)
return retval;
- retval = udev->state == UIST_CREATED ?
- uinput_inject_event(udev, buffer, count) :
- uinput_setup_device(udev, buffer, count);
+ if (udev->state == UIST_CREATED)
+ retval = uinput_inject_event(udev, buffer, count);
+ else if (count <= sizeof(struct uinput_user_dev))
+ retval = uinput_setup_device1(udev, buffer, count);
+ else
+ retval = uinput_setup_device2(udev, buffer, count);
mutex_unlock(&udev->mutex);
diff --git a/include/uapi/linux/uinput.h b/include/uapi/linux/uinput.h
index fe46431..c2e8710 100644
--- a/include/uapi/linux/uinput.h
+++ b/include/uapi/linux/uinput.h
@@ -134,4 +134,13 @@ struct uinput_user_dev {
__s32 absfuzz[ABS_CNT];
__s32 absflat[ABS_CNT];
};
+
+struct uinput_user_dev2 {
+ __u8 version;
+ char name[UINPUT_MAX_NAME_SIZE];
+ struct input_id id;
+ __u32 ff_effects_max;
+ struct input_absinfo abs[ABS_CNT];
+};
+
#endif /* _UAPI__UINPUT_H_ */
--
1.8.4.1
--
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