HID: core: fix off-by-one memset in hid_report_raw_event()

commit 5ebdffd25098898aff1249ae2f7dbfddd76d8f8f upstream.

In case a report is greater than HID_MAX_BUFFER_SIZE, it is truncated,
but the report-number byte is not correctly handled. This results in a
off-by-one in the following memset, causing a kernel Oops and ensuing
system crash.

Note: With commit 8ec321e96e05 ("HID: Fix slab-out-of-bounds read in
hid_field_extract") I no longer hit the kernel Oops as we instead fail
"controlled" at probe if there is a report too long in the HID
report-descriptor. hid_report_raw_event() is an exported symbol, so
presumabely we cannot always rely on this being the case.

Fixes: 966922f26c ("HID: fix a crash in hid_report_raw_event()
                     function.")
Signed-off-by: Johan Korsnes <[email protected]>
Cc: Armando Visconti <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Alan Stern <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
Johan Korsnes 2020-01-17 13:08:35 +01:00 • committed by Greg Kroah-Hartman
commit 819f8ab78a

View file

@ -1741,7 +1741,9 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
rsize = ((report->size - 1) >> 3) + 1;
if (rsize > HID_MAX_BUFFER_SIZE)
if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE)
rsize = HID_MAX_BUFFER_SIZE - 1;
else if (rsize > HID_MAX_BUFFER_SIZE)
rsize = HID_MAX_BUFFER_SIZE;
if (csize < rsize) {