[PATCH 3.16 009/366] HID: i2c-hid: fix size check and type usage

Ben Hutchings
2018-10-14T15:25:40Z

From: Aaron Ma <aaron.ma@canonical.com>

commit ac75a041048b8c1f7418e27621ca5efda8571043 upstream.

When convert char array with signed int, if the inbuf[x] is negative then
upper bits will be set to 1. Fix this by using u8 instead of char.

ret_size has to be at least 3, hid_input_report use it after minus 2 bytes.

Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/hid/i2c-hid/i2c-hid.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -136,10 +136,10 @@ struct i2c_hid {
* register of the HID
* descriptor. */
unsigned int bufsize; /* i2c buffer size */
- char *inbuf; /* Input buffer */
- char *rawbuf; /* Raw Input buffer */
- char *cmdbuf; /* Command buffer */
- char *argsbuf; /* Command arguments buffer */
+ u8 *inbuf; /* Input buffer */
+ u8 *rawbuf; /* Raw Input buffer */
+ u8 *cmdbuf; /* Command buffer */
+ u8 *argsbuf; /* Command arguments buffer */

unsigned long flags; /* device flags */

@@ -373,7 +373,8 @@ static int i2c_hid_hwreset(struct i2c_cl

static void i2c_hid_get_input(struct i2c_hid *ihid)
{
- int ret, ret_size;
+ int ret;
+ u32 ret_size;
int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);

if (size > ihid->bufsize)
@@ -398,7 +399,7 @@ static void i2c_hid_get_input(struct i2c
return;
}

- if (ret_size > size) {
+ if ((ret_size > size) || (ret_size <= 2)) {
dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
__func__, size, ret_size);
return;