Re: [PATCHv2] si2157: Bounds check firmware

[Olli Salonen]

Reviewed-by: Olli Salonen <olli.salonen@xxxxxx>
Tested-by: Olli Salonen <olli.salonen@xxxxxx>


On 6 October 2015 at 01:33, Laura Abbott <labbott@xxxxxxxxxxxxxxxxx> wrote:
>
> When reading the firmware and sending commands, the length
> must be bounds checked to avoid overrunning the size of the command
> buffer and smashing the stack if the firmware is not in the
> expected format. Add the proper check.
>
> Cc: stable@xxxxxxxxxx
> Signed-off-by: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx>
> ---
> v2: Set the return code properly
> ---
>  drivers/media/tuners/si2157.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c
> index 5073821..0e1ca2b 100644
> --- a/drivers/media/tuners/si2157.c
> +++ b/drivers/media/tuners/si2157.c
> @@ -166,6 +166,11 @@ static int si2157_init(struct dvb_frontend *fe)
>
>         for (remaining = fw->size; remaining > 0; remaining -= 17) {
>                 len = fw->data[fw->size - remaining];
> +               if (len > SI2157_ARGLEN) {
> +                       dev_err(&client->dev, "Bad firmware length\n");
> +                       ret = -EINVAL;
> +                       goto err_release_firmware;
> +               }
>                 memcpy(cmd.args, &fw->data[(fw->size - remaining) + 1], len);
>                 cmd.wlen = len;
>                 cmd.rlen = 1;
> --
> 2.4.3
>
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