From 3a2df60200a03f78173f1fd831aa54c08464dcde Mon Sep 17 00:00:00 2001 From: Biswarup Pal Date: Mon, 1 May 2023 20:19:19 -0700 Subject: [PATCH] Input: uinput - allow injecting event times Currently, uinput doesn't use the input_set_timestamp API, so any event injected using uinput is not accurately timestamped in terms of measuring when the actual event happened. Hence, call the input_set_timestamp API from uinput in order to provide a more accurate sense of time for the event. Propagate only the timestamps which are a) positive, b) within a pre-defined offset (10 secs) from the current time, and c) not in the future. Signed-off-by: Biswarup Pal Reviewed-by: Peter Hutterer Reviewed-by: Siarhei Vishniakou Link: https://lore.kernel.org/r/20230427000152.1407471-1-biswarupp@google.com Signed-off-by: Dmitry Torokhov --- drivers/input/misc/uinput.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index f2593133e524..d98212d55108 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -33,6 +33,7 @@ #define UINPUT_NAME "uinput" #define UINPUT_BUFFER_SIZE 16 #define UINPUT_NUM_REQUESTS 16 +#define UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS 10 enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED }; @@ -569,11 +570,40 @@ static int uinput_setup_device_legacy(struct uinput_device *udev, return retval; } +/* + * Returns true if the given timestamp is valid (i.e., if all the following + * conditions are satisfied), false otherwise. + * 1) given timestamp is positive + * 2) it's within the allowed offset before the current time + * 3) it's not in the future + */ +static bool is_valid_timestamp(const ktime_t timestamp) +{ + ktime_t zero_time; + ktime_t current_time; + ktime_t min_time; + ktime_t offset; + + zero_time = ktime_set(0, 0); + if (ktime_compare(zero_time, timestamp) >= 0) + return false; + + current_time = ktime_get(); + offset = ktime_set(UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS, 0); + min_time = ktime_sub(current_time, offset); + + if (ktime_after(min_time, timestamp) || ktime_after(timestamp, current_time)) + return false; + + return true; +} + static ssize_t uinput_inject_events(struct uinput_device *udev, const char __user *buffer, size_t count) { struct input_event ev; size_t bytes = 0; + ktime_t timestamp; if (count != 0 && count < input_event_size()) return -EINVAL; @@ -588,6 +618,10 @@ static ssize_t uinput_inject_events(struct uinput_device *udev, if (input_event_from_user(buffer + bytes, &ev)) return -EFAULT; + timestamp = ktime_set(ev.input_event_sec, ev.input_event_usec * NSEC_PER_USEC); + if (is_valid_timestamp(timestamp)) + input_set_timestamp(udev->dev, timestamp); + input_event(udev->dev, ev.type, ev.code, ev.value); bytes += input_event_size(); cond_resched();