[PATCH 1/2] fbconsole: check cursor position before moving

[Ian Abbott]

On 24/02/17 07:32, Sascha Hauer wrote:
> On Thu, Feb 23, 2017 at 06:20:21PM +0100, Bastian Stender wrote:
>> Moving the cursor to x=2, y=2 with "\e[3;3H" on a 12x2 framebuffer
>> console lead to a barebox crash while drawing the cursor. The cursor can
>> only be moved to a valid position between (0,0) and (priv->cols,
>> priv->rows) now.
>>
>> Signed-off-by: Bastian Stender <bst at pengutronix.de>
>> ---
>>  drivers/video/fbconsole.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/video/fbconsole.c b/drivers/video/fbconsole.c
>> index 64f7d7364e..3879741b2a 100644
>> --- a/drivers/video/fbconsole.c
>> +++ b/drivers/video/fbconsole.c
>> @@ -264,10 +264,13 @@ static void fbc_parse_csi(struct fbc_priv *priv)
>>  		return;
>>  	case 'H':
>>  		video_invertchar(priv, priv->x, priv->y);
>> +
>>  		pos = simple_strtoul(priv->csi, &end, 10);
>> -		priv->y = pos ? pos - 1 : 0;
>> +		priv->y = (pos && pos <= priv->rows + 1) ? pos - 1 : 0;
>> +
>>  		pos = simple_strtoul(end + 1, NULL, 10);
>> -		priv->x = pos ? pos - 1 : 0;
>> +		priv->x = (pos && pos <= priv->cols + 1) ? pos - 1 : 0;
>> +
>
> When moving out of the screen shouldn't we place the cursor on the
> bottom right corner of the screen? With this patch we move it to the top
> left corner.

Or clip to each edge, something like:

  priv->y = !pos ? 0 : pos < priv->rows ? pos - 1 : priv->rows - 1;

Same for priv->x and priv->cols?

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti at mev.co.uk> )=-
-=(                          Web: http://www.mev.co.uk/  )=-