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Message-Id: <20200305171309.29118-3-sashal@kernel.org>
Date: Thu, 5 Mar 2020 12:12:04 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Johan Korsnes <jkorsnes@...co.com>,
Armando Visconti <armando.visconti@...com>,
Jiri Kosina <jkosina@...e.cz>,
Alan Stern <stern@...land.harvard.edu>,
Sasha Levin <sashal@...nel.org>, linux-input@...r.kernel.org
Subject: [PATCH AUTOSEL 5.5 03/67] HID: core: fix off-by-one memset in hid_report_raw_event()
From: Johan Korsnes <jkorsnes@...co.com>
[ Upstream commit 5ebdffd25098898aff1249ae2f7dbfddd76d8f8f ]
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 <jkorsnes@...co.com>
Cc: Armando Visconti <armando.visconti@...com>
Cc: Jiri Kosina <jkosina@...e.cz>
Cc: Alan Stern <stern@...land.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
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 851fe54ea59e7..359616e3efbbb 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) {
--
2.20.1
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