On Fri, Aug 23, 2024 at 01:10:49PM -0700, Dmitry Torokhov wrote:

Hi Dan,

On Fri, Aug 23, 2024 at 03:51:27PM +0300, Dan Carpenter wrote:

quoted

GOODIX_HID_PKG_LEN_SIZE defined as sizeof(u16) (type size_t).  If the
goodix_hid_check_ack_status() function times out and return -EINVAL then,
because of type promotion, the negative error code is treated as a high
positive value which is success.

Fix this by adding an explicit check for negative error codes.

Fixes: 75e16c8ce283 ("HID: hid-goodix: Add Goodix HID-over-SPI driver")
Signed-off-by: Dan Carpenter <redacted>
---
 drivers/hid/hid-goodix-spi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-goodix-spi.c b/drivers/hid/hid-goodix-spi.c
index 5103bf0aada4..59415f95c675 100644
--- a/drivers/hid/hid-goodix-spi.c
+++ b/drivers/hid/hid-goodix-spi.c

@@ -435,7 +435,8 @@ static int goodix_hid_get_raw_report(struct hid_device *hid,
 
 	/* Step2: check response data status */
 	response_data_len = goodix_hid_check_ack_status(ts);
-	if (response_data_len <= GOODIX_HID_PKG_LEN_SIZE)
+	if (response_data_len < 0 ||
+	    response_data_len <= GOODIX_HID_PKG_LEN_SIZE)
 		return -EINVAL;

I think this is too subtle and we may lose your fix again in
restructuring/refactoring. Could you change goodix_hid_check_ack_status()
to take length as an argument to be filled in? And then we'd do:

	error = goodix_hid_check_ack_status(ts, &response_data_len);
	if (error)
		return error;

The check for the correct length of the response could go into
goodix_hid_check_ack_status() as well.

What do you think?

I'm fine with this.

I bet that you already wrote the patch that your describing.  If you want to
just merge that and give me reported-by credit then that's fine by me.

I can also resend.  I don't mind doing that.  I've already written the patch
that you're describing and I just have to write the commit message and hit send.
I can send it on Monday.  Whatever is easiest.

regards,
dan carpenter