From 5ebdffd25098898aff1249ae2f7dbfddd76d8f8f Mon Sep 17 00:00:00 2001 From: Johan Korsnes Date: Fri, 17 Jan 2020 13:08:35 +0100 Subject: [PATCH] HID: core: fix off-by-one memset in hid_report_raw_event() 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: 966922f26c7f ("HID: fix a crash in hid_report_raw_event() function.") Signed-off-by: Johan Korsnes Cc: Armando Visconti Cc: Jiri Kosina Cc: Alan Stern Signed-off-by: Jiri Kosina --- 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) { -- 2.11.0