From 9933a927ded632fde949e0ef6f7a201534d2add8 Mon Sep 17 00:00:00 2001 From: Seth Forshee Date: Fri, 20 Feb 2015 11:45:11 -0600 Subject: [PATCH] HID: i2c-hid: Limit reads to wMaxInputLength bytes for input events commit 6d00f37e49d95e640a3937a4a1ae07dbe92a10cb upstream. d1c7e29e8d27 (HID: i2c-hid: prevent buffer overflow in early IRQ) changed hid_get_input() to read ihid->bufsize bytes, which can be more than wMaxInputLength. This is the case with the Dell XPS 13 9343, and it is causing events to be missed. In some cases the missed events are releases, which can cause the cursor to jump or freeze, among other problems. Limit the number of bytes read to min(wMaxInputLength, ihid->bufsize) to prevent such problems. Fixes: d1c7e29e8d27 "HID: i2c-hid: prevent buffer overflow in early IRQ" Signed-off-by: Seth Forshee Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/i2c-hid/i2c-hid.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index d43e967e75339..5e72fc2428f0b 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -370,7 +370,10 @@ static int i2c_hid_hwreset(struct i2c_client *client) static void i2c_hid_get_input(struct i2c_hid *ihid) { int ret, ret_size; - int size = ihid->bufsize; + int size = le16_to_cpu(ihid->hdesc.wMaxInputLength); + + if (size > ihid->bufsize) + size = ihid->bufsize; ret = i2c_master_recv(ihid->client, ihid->inbuf, size); if (ret != size) { -- 2.47.2