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. I still believe this is worth fixing though, as
hid_report_raw_event() should have its logic correct. But if we fail at
probe for too large reports, a better solution might be to remove this
truncation logic entirely.
Fixes: 966922f26c7f ("HID: fix a crash in hid_report_raw_event()
function.")
Signed-off-by: Johan Korsnes <jkorsnes@xxxxxxxxx>
Cc: Armando Visconti <armando.visconti@xxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
drivers/hid/hid-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 851fe54ea59e..359616e3efbb 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -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) {
--
2.24.1
