diff mbox

[14/14] HID: i2c-hid: fix i2c_hid_get_raw_report count mismatches

Message ID 1354634875-5182-15-git-send-email-benjamin.tissoires@gmail.com (mailing list archive)
State New, archived
Delegated to: Jiri Kosina
Headers show

Commit Message

Benjamin Tissoires Dec. 4, 2012, 3:27 p.m. UTC
The previous memcpy implementation relied on the size advertized by the
device. There were no guarantees that buf was big enough.

Some gymnastic is also required with the +2/-2 to take into account
the first 2 bytes where the total length is supplied by the device.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
---
 drivers/hid/i2c-hid/i2c-hid.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Comments

Benjamin Tissoires Dec. 5, 2012, 10:40 a.m. UTC | #1
Hi,

sorry, but when I re-read it, it seems that I missed a +2 in the call
of i2c_hid_get_report.

So Jean, Jiri, please ignore this one. I'm really sorry if you already
started reviewing it.

I'll send a v2 with the missing patches early this afternoon.

Cheers,
Benjamin

On Tue, Dec 4, 2012 at 4:27 PM, Benjamin Tissoires
<benjamin.tissoires@gmail.com> wrote:
> The previous memcpy implementation relied on the size advertized by the
> device. There were no guarantees that buf was big enough.
>
> Some gymnastic is also required with the +2/-2 to take into account
> the first 2 bytes where the total length is supplied by the device.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
> ---
>  drivers/hid/i2c-hid/i2c-hid.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 62988f1..de3566f 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -503,13 +503,14 @@ static int i2c_hid_get_raw_report(struct hid_device *hid,
>  {
>         struct i2c_client *client = hid->driver_data;
>         struct i2c_hid *ihid = i2c_get_clientdata(client);
> +       size_t rcount;
>         int ret;
>
>         if (report_type == HID_OUTPUT_REPORT)
>                 return -EINVAL;
>
> -       if (count > ihid->bufsize)
> -               count = ihid->bufsize;
> +       if (count > ihid->bufsize - 2)
> +               count = ihid->bufsize - 2;
>
>         ret = i2c_hid_get_report(client,
>                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> @@ -518,7 +519,13 @@ static int i2c_hid_get_raw_report(struct hid_device *hid,
>         if (ret < 0)
>                 return ret;
>
> -       count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> +       rcount = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> +
> +       if (!rcount)
> +               return 0;
> +
> +       if (count > rcount - 2)
> +               count = rcount - 2;
>
>         memcpy(buf, ihid->inbuf + 2, count);
>
> --
> 1.8.0.1
>
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diff mbox

Patch

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 62988f1..de3566f 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -503,13 +503,14 @@  static int i2c_hid_get_raw_report(struct hid_device *hid,
 {
 	struct i2c_client *client = hid->driver_data;
 	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	size_t rcount;
 	int ret;
 
 	if (report_type == HID_OUTPUT_REPORT)
 		return -EINVAL;
 
-	if (count > ihid->bufsize)
-		count = ihid->bufsize;
+	if (count > ihid->bufsize - 2)
+		count = ihid->bufsize - 2;
 
 	ret = i2c_hid_get_report(client,
 			report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
@@ -518,7 +519,13 @@  static int i2c_hid_get_raw_report(struct hid_device *hid,
 	if (ret < 0)
 		return ret;
 
-	count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
+	rcount = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
+
+	if (!rcount)
+		return 0;
+
+	if (count > rcount - 2)
+		count = rcount - 2;
 
 	memcpy(buf, ihid->inbuf + 2, count);