media: synopsys: hdmirx: fix integer overflow in hdmirx_get_edid()

[PATCH] media: synopsys: hdmirx: fix integer overflow in hdmirx_get_edid()

Posted by Dan Carpenter 1 month ago

The "edid->blocks" variable comes from the user via the ioctl.  It's
a u32 and "edid->start_block" is a u32 too.  The addition operation
could have an integer wrapping bug, so use the size_add() function to
prevent that.

Cc: stable@vger.kernel.org
Fixes: 7b59b132ad43 ("media: platform: synopsys: Add support for HDMI input driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
 drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
index c3007e09bc9f..f054e30cbfb0 100644
--- a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
+++ b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
@@ -717,7 +717,7 @@ static int hdmirx_get_edid(struct file *file, void *fh, struct v4l2_edid *edid)
 	if (edid->start_block >= hdmirx_dev->edid_blocks_written || !edid->blocks)
 		return -EINVAL;
 
-	if (edid->start_block + edid->blocks > hdmirx_dev->edid_blocks_written)
+	if (size_add(edid->start_block, edid->blocks) > hdmirx_dev->edid_blocks_written)
 		edid->blocks = hdmirx_dev->edid_blocks_written - edid->start_block;
 
 	memcpy(edid->edid, hdmirx_dev->edid, edid->blocks * EDID_BLOCK_SIZE);
-- 
2.51.0

Re: [PATCH] media: synopsys: hdmirx: fix integer overflow in hdmirx_get_edid()

Posted by Dmitry Osipenko 1 month ago

On 1/8/26 23:03, Dan Carpenter wrote:
> The "edid->blocks" variable comes from the user via the ioctl.  It's
> a u32 and "edid->start_block" is a u32 too.  The addition operation
> could have an integer wrapping bug, so use the size_add() function to
> prevent that.
> 
> Cc: stable@vger.kernel.org
> Fixes: 7b59b132ad43 ("media: platform: synopsys: Add support for HDMI input driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>  drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
> index c3007e09bc9f..f054e30cbfb0 100644
> --- a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
> +++ b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
> @@ -717,7 +717,7 @@ static int hdmirx_get_edid(struct file *file, void *fh, struct v4l2_edid *edid)
>  	if (edid->start_block >= hdmirx_dev->edid_blocks_written || !edid->blocks)
>  		return -EINVAL;
>  
> -	if (edid->start_block + edid->blocks > hdmirx_dev->edid_blocks_written)
> +	if (size_add(edid->start_block, edid->blocks) > hdmirx_dev->edid_blocks_written)
>  		edid->blocks = hdmirx_dev->edid_blocks_written - edid->start_block;
>  
>  	memcpy(edid->edid, hdmirx_dev->edid, edid->blocks * EDID_BLOCK_SIZE);

Acked-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>

-- 
Best regards,
Dmitry