On Tue, Jan 31, 2023 at 02:05:52AM -0500, Liu Xiaodong wrote:
> When validating drafted SPDK ublk target, in a case that
> assigning large queue depth to multiqueue ublk device,
> ublk target would run into a weird incorrect state. During
> rounds of review and debug, An overflow bug was found
> in ublk driver.
>
> In ublk_cmd.h, UBLK_MAX_QUEUE_DEPTH is 4096 which means
> each ublk queue depth can be set as large as 4096. But
> when setting qd for a ublk device,
> sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io)
> will be larger than 65535 if qd is larger than 2728.
> Then queue_size is overflowed, and ublk_get_queue()
> references a wrong pointer position. The wrong content of
> ublk_queue elements will lead to out-of-bounds memory
> access.
>
> Extend queue_size in ublk_device as "unsigned int".
>
> Signed-off-by: Liu Xiaodong <xiaodong.liu@xxxxxxxxx>
> ---
> drivers/block/ublk_drv.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index e54693204630..6368b56eacf1 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -137,7 +137,7 @@ struct ublk_device {
>
> char *__queues;
>
> - unsigned short queue_size;
> + unsigned int queue_size;
> struct ublksrv_ctrl_dev_info dev_info;
Good catch,
Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Thanks,
Ming
