Re: [PATCH] Input: wacom_w8001 - Ignore bogus idx values in interrupt
From: Ping Cheng <hidden>
Date: 2016-05-23 05:22:09
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lkml
Hi Chris, On Sun, May 22, 2016 at 6:42 PM, Chris J Arges [off-list ref] wrote:
I've noticed crashes when using my x60t using a coreboot bios. When using the pen I can produce a crash simply by tapping a few times. This generates an event which has an idx of 0xc. This in turn crashes the machine because the array access is greater than W8001_MAX_LENGTH. This patch checks for bogus values and filters them in order to prevent crashes.
Thank you for submitting a patch in addition to reporting the issue.
quoted hunk ↗ jump to hunk
Signed-off-by: Chris J Arges <redacted> --- drivers/input/touchscreen/wacom_w8001.c | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c index bab3c6a..c858200 100644 --- a/drivers/input/touchscreen/wacom_w8001.c +++ b/drivers/input/touchscreen/wacom_w8001.c@@ -283,6 +283,15 @@ static irqreturn_t w8001_interrupt(struct serio *serio, unsigned char tmp; w8001->data[w8001->idx] = data; + + /* ignore bogus idx values */ + if (w8001->idx >= W8001_MAX_LENGTH) { + pr_info("w8001: ignored interrupt: data 0x%02x idx %d\n", data, + w8001->idx); + w8001->idx = 0; + return IRQ_HANDLED; + } +
I don't have an x60t system to test with. I wonder if your system supports two finger touch or not. We at least have a bug in the code since W8001_MAX_LENGTH should be 13 instead of 11. How come no one had encountered that issue before? I'm going to email a patch to the list. Please test it and let us know your result. Maybe we still need your patch if your device doesn't support two finger touch or the idx=0xc can't be fixed by W8001_MAX_LENGTH=13. Thanks, Ping
switch (w8001->idx++) {
case 0:
if ((data & W8001_LEAD_MASK) != W8001_LEAD_BYTE) {
--
2.7.4
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