[PATCH v3] fbconsole: check cursor position before moving

[Ian Abbott]

On 27/02/17 18:46, Ian Abbott wrote:
> On 27/02/17 13:39, 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. If the
>> cursor position is out of bounds clip the cursor to the corresponding
>> edge.
>>
>> 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..33649c597d 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 = clamp(pos - 1, 0, (int) priv->rows);
>> +
>
> That allows priv->y to be set to priv->rows, which is one too many.

Ignore that.  My mistake.  It appears that priv->rows is the number of 
rows minus 1, so the above code is fine.  Same for priv->x.

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