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authorSeth Forshee <seth.forshee@canonical.com>2015-02-20 11:45:11 -0600
committerJiri Slaby <jslaby@suse.cz>2015-03-01 23:34:14 +0100
commit86705a9be3029fc8a1c287f421eecd89b4a68504 (patch)
treee4b6b752ebb6e7cdec14d548af49d3b7a5eda8a4 /drivers/hid
parenta113cc3fe1778e770eb5c77a34dc03ecd5fe8da6 (diff)
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: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'drivers/hid')
-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 e29d8a0feb5f..f62c65ec117e 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -356,7 +356,10 @@ 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) {