[PATCH 3.16 004/125] HID: logitech: perform bounds checking on device_id early enough

Greg Kroah-Hartman
2014-09-03T22:18:39Z

From: Jiri Kosina <jkosina@suse.cz>

commit ad3e14d7c5268c2e24477c6ef54bbdf88add5d36 upstream.

device_index is a char type and the size of paired_dj_deivces is 7
elements, therefore proper bounds checking has to be applied to
device_index before it is used.

We are currently performing the bounds checking in
logi_dj_recv_add_djhid_device(), which is too late, as malicious device
could send REPORT_TYPE_NOTIF_DEVICE_UNPAIRED early enough and trigger the
problem in one of the report forwarding functions called from
logi_dj_raw_event().

Fix this by performing the check at the earliest possible ocasion in
logi_dj_raw_event().

Reported-by: Ben Hawkes <hawkes@google.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>

---
drivers/hid/hid-logitech-dj.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -238,13 +238,6 @@ static void logi_dj_recv_add_djhid_devic
return;
}

- if ((dj_report->device_index < DJ_DEVICE_INDEX_MIN) ||
- (dj_report->device_index > DJ_DEVICE_INDEX_MAX)) {
- dev_err(&djrcv_hdev->dev, "%s: invalid device index:%d\n",
- __func__, dj_report->device_index);
- return;
- }
-
if (djrcv_dev->paired_dj_devices[dj_report->device_index]) {
/* The device is already known. No need to reallocate it. */
dbg_hid("%s: device is already known\n", __func__);
@@ -690,6 +683,12 @@ static int logi_dj_raw_event(struct hid_
* device (via hid_input_report() ) and return 1 so hid-core does not do
* anything else with it.
*/
+ if ((dj_report->device_index < DJ_DEVICE_INDEX_MIN) ||
+ (dj_report->device_index > DJ_DEVICE_INDEX_MAX)) {
+ dev_err(&hdev->dev, "%s: invalid device index:%d\n",
+ __func__, dj_report->device_index);
+ return false;
+ }

spin_lock_irqsave(&djrcv_dev->lock, flags);
if (dj_report->report_id == REPORT_ID_DJ_SHORT) {