Re: [Qemu-devel] [PATCH] macio: fix overflow in lba to offset conversion for ATAPI devices

[John Snow <jsnow@redhat.com>]

On 01/04/2016 12:30 PM, Mark Cave-Ayland wrote:
> As the IDEState lba field is an int32_t, make sure we cast to int64_t before
> shifting to calculate the offset. Otherwise we end up with an overflow when
> trying to access sectors beyond 2GB as can occur when using DVD images.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  hw/ide/macio.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/ide/macio.c b/hw/ide/macio.c
> index 3ee962f..a78b6e0 100644
> --- a/hw/ide/macio.c
> +++ b/hw/ide/macio.c
> @@ -280,7 +280,7 @@ static void pmac_ide_atapi_transfer_cb(void *opaque, int ret)
>      }
>  
>      /* Calculate current offset */
> -    offset = (int64_t)(s->lba << 11) + s->io_buffer_index;
> +    offset = ((int64_t)(s->lba) << 11) + s->io_buffer_index;
>  
>      pmac_dma_read(s->blk, offset, io->len, pmac_ide_atapi_transfer_cb, io);
>      return;
> 

Thanks, applied to my IDE tree:

https://github.com/jnsnow/qemu/commits/ide
https://github.com/jnsnow/qemu.git

--js