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authorAlan Stern <stern@rowland.harvard.edu>2019-10-03 14:53:59 -0400
committerBenjamin Tissoires <benjamin.tissoires@redhat.com>2019-10-03 15:36:40 -0400
commitd9d4b1e46d9543a82c23f6df03f4ad697dab361b (patch)
tree5a405a2f78b1029f4cc6d6ee743f0bec31319b42 /drivers/hid/hid-dr.c
parentfe2199cfd1516e90e03c033c52c9a28da09d9986 (diff)
HID: Fix assumption that devices have inputs
The syzbot fuzzer found a slab-out-of-bounds write bug in the hid-gaff driver. The problem is caused by the driver's assumption that the device must have an input report. While this will be true for all normal HID input devices, a suitably malicious device can violate the assumption. The same assumption is present in over a dozen other HID drivers. This patch fixes them by checking that the list of hid_inputs for the hid_device is nonempty before allowing it to be used. Reported-and-tested-by: syzbot+403741a091bf41d4ae79@syzkaller.appspotmail.com Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: <stable@vger.kernel.org> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Diffstat (limited to 'drivers/hid/hid-dr.c')
-rw-r--r--drivers/hid/hid-dr.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/hid/hid-dr.c b/drivers/hid/hid-dr.c
index 17e17f9a597b..947f19f8685f 100644
--- a/drivers/hid/hid-dr.c
+++ b/drivers/hid/hid-dr.c
@@ -75,13 +75,19 @@ static int drff_init(struct hid_device *hid)
{
struct drff_device *drff;
struct hid_report *report;
- struct hid_input *hidinput = list_first_entry(&hid->inputs,
- struct hid_input, list);
+ struct hid_input *hidinput;
struct list_head *report_list =
&hid->report_enum[HID_OUTPUT_REPORT].report_list;
- struct input_dev *dev = hidinput->input;
+ struct input_dev *dev;
int error;
+ if (list_empty(&hid->inputs)) {
+ hid_err(hid, "no inputs found\n");
+ return -ENODEV;
+ }
+ hidinput = list_first_entry(&hid->inputs, struct hid_input, list);
+ dev = hidinput->input;
+
if (list_empty(report_list)) {
hid_err(hid, "no output reports found\n");
return -ENODEV;