From: Jason Gerecke killertofu@gmail.com
stable inclusion from stable-v5.10.94 commit 57cfc965e3754868b0686d2700d9ea869dee48ea bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 20f3cf5f860f9f267a6a6e5642d3d0525edb1814 upstream.
If we ever see a touch report with contact count data we initialize several variables used to read the contact count in the pre-report phase. These variables are never reset if we process a report which doesn't contain a contact count, however. This can cause the pre- report function to trigger a read of arbitrary memory (e.g. NULL if we're lucky) and potentially crash the driver.
This commit restores resetting of the variables back to default "none" values that were used prior to the commit mentioned below.
Link: https://github.com/linuxwacom/input-wacom/issues/276 Fixes: 003f50ab673c (HID: wacom: Update last_slot_field during pre_report phase) CC: stable@vger.kernel.org Signed-off-by: Jason Gerecke jason.gerecke@wacom.com Reviewed-by: Ping Cheng ping.cheng@wacom.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/hid/wacom_wac.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c index 4f10b8317ba7..d90bfa8b7313 100644 --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2654,6 +2654,10 @@ static void wacom_wac_finger_pre_report(struct hid_device *hdev,
hid_data->confidence = true;
+ hid_data->cc_report = 0; + hid_data->cc_index = -1; + hid_data->cc_value_index = -1; + for (i = 0; i < report->maxfield; i++) { struct hid_field *field = report->field[i]; int j;