The issue is GOODIX_HID_PKG_LEN_SIZE is defined as sizeof(u16) which is
type size_t. However, goodix_hid_check_ack_status() returns negative
error codes or potentially a positive but invalid length which is too
small. So when we compare "if ((response_data_len <=
GOODIX_HID_PKG_LEN_SIZE)" then negative error codes are type promoted to
size_t and counted as a positive large value and treated as valid.
It would have been easy enough to add some casting to avoid the type
promotion, however this patch takes a more thourough approach and moves
the length check into goodix_hid_check_ack_status(). Now the function
only return negative error codes or zero on success and the length
pointer is never set to an invalid length.
Fixes: 75e16c8ce283 ("HID: hid-goodix: Add Goodix HID-over-SPI driver")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
v2: take a different approach
drivers/hid/hid-goodix-spi.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/hid/hid-goodix-spi.c b/drivers/hid/hid-goodix-spi.c
index 5103bf0aada4..de655f745d3f 100644
--- a/drivers/hid/hid-goodix-spi.c
+++ b/drivers/hid/hid-goodix-spi.c
@@ -335,11 +335,12 @@ static void goodix_hid_close(struct hid_device *hid)
}
/* Return date length of response data */
-static int goodix_hid_check_ack_status(struct goodix_ts_data *ts)
+static int goodix_hid_check_ack_status(struct goodix_ts_data *ts, u32 *resp_len)
{
struct goodix_hid_report_header hdr;
int retry = 20;
int error;
+ int len;
while (retry--) {
/*
@@ -349,8 +350,15 @@ static int goodix_hid_check_ack_status(struct goodix_ts_data *ts)
*/
error = goodix_spi_read(ts, ts->hid_report_addr,
&hdr, sizeof(hdr));
- if (!error && (hdr.flag & GOODIX_HID_ACK_READY_FLAG))
- return le16_to_cpu(hdr.size);
+ if (!error && (hdr.flag & GOODIX_HID_ACK_READY_FLAG)) {
+ len = le16_to_cpu(hdr.size);
+ if (len < GOODIX_HID_PKG_LEN_SIZE) {
+ dev_err(ts->dev, "hrd.size too short: %d", len);
+ return -EINVAL;
+ }
+ *resp_len = len;
+ return 0;
+ }
/* Wait 10ms for another try */
usleep_range(10000, 11000);
@@ -383,7 +391,7 @@ static int goodix_hid_get_raw_report(struct hid_device *hid,
u16 cmd_register = le16_to_cpu(ts->hid_desc.cmd_register);
u8 tmp_buf[GOODIX_HID_MAX_INBUF_SIZE];
int tx_len = 0, args_len = 0;
- int response_data_len;
+ u32 response_data_len;
u8 args[3];
int error;
@@ -434,9 +442,9 @@ static int goodix_hid_get_raw_report(struct hid_device *hid,
return 0;
/* Step2: check response data status */
- response_data_len = goodix_hid_check_ack_status(ts);
- if (response_data_len <= GOODIX_HID_PKG_LEN_SIZE)
- return -EINVAL;
+ error = goodix_hid_check_ack_status(ts, &response_data_len);
+ if (error)
+ return error;
len = min(len, response_data_len - GOODIX_HID_PKG_LEN_SIZE);
/* Step3: read response data(skip 2bytes of hid pkg length) */
--
2.43.0
