On Fri, 7 Oct 2016 14:24:18 -0300
Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> wrote:
> Be sure that I2C reads won't use stack by passing
> a pointer to the state buffer, that we know it was
> allocated via kmalloc, instead of relying on the buffer
> allocated by an I2C client.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/usb/dvb-usb/dib0700_core.c | 27
> ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1
> deletion(-)
>
> diff --git a/drivers/media/usb/dvb-usb/dib0700_core.c
> b/drivers/media/usb/dvb-usb/dib0700_core.c index
> 515f89dba199..92d5408684ac 100644 ---
> a/drivers/media/usb/dvb-usb/dib0700_core.c +++
> b/drivers/media/usb/dvb-usb/dib0700_core.c @@ -213,7 +213,7 @@ static
> int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg
> *msg, usb_rcvctrlpipe(d->udev, 0), REQUEST_NEW_I2C_READ,
> USB_TYPE_VENDOR |
> USB_DIR_IN,
> - value, index,
> msg[i].buf,
> + value, index,
> st->buf, msg[i].len,
> USB_CTRL_GET_TIMEOUT);
> if (result < 0) {
> @@ -221,6 +221,14 @@ static int dib0700_i2c_xfer_new(struct
> i2c_adapter *adap, struct i2c_msg *msg, break;
> }
>
> + if (msg[i].len > sizeof(st->buf)) {
> + deb_info("buffer too small to fit %d
> bytes\n",
> + msg[i].len);
> + return -EIO;
> + }
> +
> + memcpy(msg[i].buf, st->buf, msg[i].len);
> +
> deb_data("<<< ");
> debug_dump(msg[i].buf, msg[i].len, deb_data);
>
> @@ -238,6 +246,13 @@ static int dib0700_i2c_xfer_new(struct
> i2c_adapter *adap, struct i2c_msg *msg, /* I2C ctrl + FE bus; */
> st->buf[3] = ((gen_mode << 6) & 0xC0) |
> ((bus_mode << 4) & 0x30);
> +
> + if (msg[i].len > sizeof(st->buf) - 4) {
> + deb_info("i2c message to big: %d\n",
> + msg[i].len);
> + return -EIO;
> + }
> +
> /* The Actual i2c payload */
> memcpy(&st->buf[4], msg[i].buf, msg[i].len);
>
> @@ -283,6 +298,11 @@ static int dib0700_i2c_xfer_legacy(struct
> i2c_adapter *adap, /* fill in the address */
> st->buf[1] = msg[i].addr << 1;
> /* fill the buffer */
> + if (msg[i].len > sizeof(st->buf) - 2) {
> + deb_info("i2c xfer to big: %d\n",
> + msg[i].len);
> + return -EIO;
> + }
> memcpy(&st->buf[2], msg[i].buf, msg[i].len);
>
> /* write/read request */
> @@ -299,6 +319,11 @@ static int dib0700_i2c_xfer_legacy(struct
> i2c_adapter *adap, break;
> }
>
> + if (msg[i + 1].len > sizeof(st->buf)) {
> + deb_info("i2c xfer buffer to small
> for %d\n",
> + msg[i].len);
> + return -EIO;
> + }
> memcpy(msg[i + 1].buf, st->buf, msg[i +
> 1].len);
> msg[i+1].len = len;
Reviewed-By: Patrick Boettcher <patrick.boettcher@xxxxxxxxx>
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