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authorSeth Forshee <seth.forshee@canonical.com>2015-02-20 11:45:11 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-06 14:40:48 -0800
commitde13322c2802b274eaff42c6027ee32e0567b75a (patch)
tree89fa93bfde00296374a673435e4383fb1e7b3d6a
parent4313b9cb8964781bed89316a3c929f56b9651f9d (diff)
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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 <seth.forshee@canonical.com> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hid/i2c-hid/i2c-hid.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 469daa04dadb..ccc2f36bb334 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -341,7 +341,10 @@ 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) {