From: Anirudh Rayabharam <mail@xxxxxxxxxxxxx>
[ Upstream commit 6be388f4a35d2ce5ef7dbf635a8964a5da7f799f ]
In hid_submit_ctrl(), the way of calculating the report length doesn't
take into account that report->size can be zero. When running the
syzkaller reproducer, a report of size 0 causes hid_submit_ctrl) to
calculate transfer_buffer_length as 16384. When this urb is passed to
the usb core layer, KMSAN reports an info leak of 16384 bytes.
To fix this, first modify hid_report_len() to account for the zero
report size case by using DIV_ROUND_UP for the division. Then, call it
from hid_submit_ctrl().
Reported-by: syzbot+7c2bb71996f95a82524c@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Anirudh Rayabharam <mail@xxxxxxxxxxxxx>
Acked-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/hid/usbhid/hid-core.c | 2 +-
include/linux/hid.h | 3 +--
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 17a29ee0ac6c..8d4ac4b9fb9d 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -374,7 +374,7 @@ static int hid_submit_ctrl(struct hid_device *hid)
raw_report = usbhid->ctrl[usbhid->ctrltail].raw_report;
dir = usbhid->ctrl[usbhid->ctrltail].dir;
- len = ((report->size - 1) >> 3) + 1 + (report->id > 0);
+ len = hid_report_len(report);
if (dir == USB_DIR_OUT) {
usbhid->urbctrl->pipe = usb_sndctrlpipe(hid_to_usb_dev(hid), 0);
usbhid->urbctrl->transfer_buffer_length = len;
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 8578db50ad73..6ed2a97eb55f 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -1156,8 +1156,7 @@ static inline void hid_hw_wait(struct hid_device *hdev)
*/
static inline u32 hid_report_len(struct hid_report *report)
{
- /* equivalent to DIV_ROUND_UP(report->size, 8) + !!(report->id > 0) */
- return ((report->size - 1) >> 3) + 1 + (report->id > 0);
+ return DIV_ROUND_UP(report->size, 8) + (report->id > 0);
}
int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
--
2.30.2
