On Wed, Nov 19, 2014 at 11:46 AM, Antonio Borneo
<borneo.antonio@xxxxxxxxx> wrote:
> From: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
>
> Current driver uses a common buffer for reading reports either
> synchronously in i2c_hid_get_raw_report() and asynchronously in
> the interrupt handler.
> There is race condition if an interrupt arrives immediately after
> the report is received in i2c_hid_get_raw_report(); the common
> buffer is modified by the interrupt handler with the new report
> and then i2c_hid_get_raw_report() proceed using wrong data.
>
> Fix it by using a separate buffers for synchronous reports.
>
> Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
> [Antonio Borneo: cleanup, rebase to v3.17, submit mainline]
> Signed-off-by: Antonio Borneo <borneo.antonio@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> V1 -> V2
> rename the synchronous buffer as rawbuf (instead of the
> asynchronous one)
Sorry for the lag and thanks for resubmitting.
This one is reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Cheers,
Benjamin
>
> drivers/hid/i2c-hid/i2c-hid.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 933bf10..c66e6ac 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -137,6 +137,7 @@ struct i2c_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 */
>
> @@ -504,9 +505,11 @@ static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
> static void i2c_hid_free_buffers(struct i2c_hid *ihid)
> {
> kfree(ihid->inbuf);
> + kfree(ihid->rawbuf);
> kfree(ihid->argsbuf);
> kfree(ihid->cmdbuf);
> ihid->inbuf = NULL;
> + ihid->rawbuf = NULL;
> ihid->cmdbuf = NULL;
> ihid->argsbuf = NULL;
> ihid->bufsize = 0;
> @@ -522,10 +525,11 @@ static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
> report_size; /* report */
>
> ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
> + ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
> ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
> ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
>
> - if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
> + if (!ihid->inbuf || !ihid->rawbuf || !ihid->argsbuf || !ihid->cmdbuf) {
> i2c_hid_free_buffers(ihid);
> return -ENOMEM;
> }
> @@ -552,12 +556,12 @@ static int i2c_hid_get_raw_report(struct hid_device *hid,
>
> ret = i2c_hid_get_report(client,
> report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> - report_number, ihid->inbuf, ask_count);
> + report_number, ihid->rawbuf, ask_count);
>
> if (ret < 0)
> return ret;
>
> - ret_count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> + ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8);
>
> if (ret_count <= 2)
> return 0;
> @@ -566,7 +570,7 @@ static int i2c_hid_get_raw_report(struct hid_device *hid,
>
> /* The query buffer contains the size, dropping it in the reply */
> count = min(count, ret_count - 2);
> - memcpy(buf, ihid->inbuf + 2, count);
> + memcpy(buf, ihid->rawbuf + 2, count);
>
> return count;
> }
> --
> 2.1.3
>
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