[U-Boot] [PATCH v5 01/15] video: bmp: check resolutions of panel/bitmap

[Patrice CHOTARD]

Hi Heinrich

On 10/24/19 10:43 PM, Heinrich Schuchardt wrote:
> On 10/24/19 4:05 PM, Patrice CHOTARD wrote:
>> Hi Heinrich, all
>>
>> On 10/7/19 7:34 PM, Heinrich Schuchardt wrote:
>>> On 10/7/19 3:29 PM, Yannick Fertré wrote:
>>>> If the size of the bitmap is bigger than the size of
>>>> the panel then errors appear when calculating axis alignment
>>>> and the copy of bitmap is done outside of framebuffer.
>>>>
>>>> Signed-off-by: Yannick Fertré <yannick.fertre at st.com>
>>>> ---
>>>>    drivers/video/video_bmp.c | 7 +++++++
>>>>    1 file changed, 7 insertions(+)
>>>>
>>>> diff --git a/drivers/video/video_bmp.c b/drivers/video/video_bmp.c
>>>> index 193f37d..4af1fb4 100644
>>>> --- a/drivers/video/video_bmp.c
>>>> +++ b/drivers/video/video_bmp.c
>>>> @@ -249,6 +249,13 @@ int video_bmp_display(struct udevice *dev, ulong bmp_image, int x, int y,
>>>>
>>>>        padded_width = (width & 0x3 ? (width & ~0x3) + 4 : width);
>>>>
>>>> +    /* check if picture size exceeds panel size */
>>>> +    if ((pwidth < width) || (priv->ysize < height)) {
>>>> +        printf("Error: BMP size %d x %d is bigger than panel size %d x %d\n",
>>>> +               (int)width, (int)height, priv->xsize, priv->ysize);
>>>> +        return -EINVAL;
>>>> +    }
>>>> +
>>>>        if (align) {
>>>>            video_splash_align_axis(&x, priv->xsize, width);
>>>>            video_splash_align_axis(&y, priv->ysize, height);
>>>
>>> This is followed by:
>>>
>>>          if ((x + width) > pwidth)
>>>                  width = pwidth - x;
>>>          if ((y + height) > priv->ysize)
>>>                  height = priv->ysize - y;
>>>
>>> These lines will clip a bitmap that given the left upper corner x, y
>>> does not fit onto the screen.
>>>
>>> So isn't this patch superfluous?
>>>
>>> What is missing are checks for x and y.
>>>
>>> For testing I have used qemu_x86 and added
>>>
>>>      #define CONFIG_BMP_24BPP y
>>>
>>> to the top of drivers/video/video_bmp.c and loaded a 24bit bitmap.
>>>
>>> Clipping works as expected. But passing a value of x exceeding the
>>> screen width lead to a crash.
>>>
>>> What I really dislike in the existing coding is that CONFIG_BMP_*BPP is
>>> defined in includes instead of using Kconfig but that is a different story.
>>>
>>> Best regards
>>>
>>> Heinrich
>>
>> For information all this series patches have been applied on u-boot/master excepts  this one.
>>
>> Unfortunately, without this patch, stm32f746-discovery board doesn't boot anymore.
>
> I still do not understand why this patch is needed.
>
> Could you, please, try to analyze why the board does not boot.
>
> What is wrong with the existing code for clipping?
> Or is the non-booting just coincidence but the bug is somewhere else?
>
> What are the values of the parameters passed to video_bmp_display()?
> Which bitmap file are you using?
> What is the size of the display?


To sum-up, on all STM32 boards, the same BMP splashcreen is used.

In the particular case of STM32F746-Disco board, the panel size is smaller then the BMP size.

So, some size check must be done to avoid overflow when writing inside the framebuffer.

If needed, Yannick, which is multimedia expert, can give you more precise details.

Thanks

Patrice


>
> Best regards
>
> Heinrich
>
>>
>> Heinrich, could this patch be merged, waiting for a clean patch from Yannick ?
>>
>> Regards
>>
>> Patrice
>>
>