Commit 5ebdffd2 authored Jan 17, 2020 by Johan Korsnes Committed by Jiri Kosina Feb 12, 2020

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 8ec321e9 ("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: 966922f2 ("HID: fix a crash in hid_report_raw_event()
                     function.")
Signed-off-by: Johan Korsnes <jkorsnes@cisco.com>
Cc: Armando Visconti <armando.visconti@st.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

parent e433be92

drivers/hid/hid-core.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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) {

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