2021-05-07 14:02:44

by Jiapeng Chong

[permalink] [raw]
Subject: [PATCH] RDMA/mlx4: Remove unnessesary check in mlx4_ib_modify_wq()

cur_state and new_state are enums and when GCC considers
them as unsigned, the conditions are never met.

Clean up the following smatch warning:

drivers/infiniband/hw/mlx4/qp.c:4258 mlx4_ib_modify_wq() warn: unsigned
'cur_state' is never less than zero.

Reported-by: Abaci Robot <[email protected]>
Signed-off-by: Jiapeng Chong <[email protected]>
---
drivers/infiniband/hw/mlx4/qp.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
index 92ddbcc..162aa59 100644
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -4255,8 +4255,7 @@ int mlx4_ib_modify_wq(struct ib_wq *ibwq, struct ib_wq_attr *wq_attr,
ibwq->state;
new_state = wq_attr_mask & IB_WQ_STATE ? wq_attr->wq_state : cur_state;

- if (cur_state < IB_WQS_RESET || cur_state > IB_WQS_ERR ||
- new_state < IB_WQS_RESET || new_state > IB_WQS_ERR)
+ if (cur_state > IB_WQS_ERR || new_state > IB_WQS_ERR)
return -EINVAL;

if ((new_state == IB_WQS_RDY) && (cur_state == IB_WQS_ERR))
--
1.8.3.1


2021-05-09 09:03:01

by Leon Romanovsky

[permalink] [raw]
Subject: Re: [PATCH] RDMA/mlx4: Remove unnessesary check in mlx4_ib_modify_wq()

On Fri, May 07, 2021 at 06:22:41PM +0800, Jiapeng Chong wrote:
> cur_state and new_state are enums and when GCC considers
> them as unsigned, the conditions are never met.
>
> Clean up the following smatch warning:
>
> drivers/infiniband/hw/mlx4/qp.c:4258 mlx4_ib_modify_wq() warn: unsigned
> 'cur_state' is never less than zero.
>
> Reported-by: Abaci Robot <[email protected]>
> Signed-off-by: Jiapeng Chong <[email protected]>
> ---
> drivers/infiniband/hw/mlx4/qp.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)

Thanks,
Reviewed-by: Leon Romanovsky <[email protected]>

2021-05-09 09:42:51

by Leon Romanovsky

[permalink] [raw]
Subject: Re: [PATCH] RDMA/mlx4: Remove unnessesary check in mlx4_ib_modify_wq()

On Fri, May 07, 2021 at 06:22:41PM +0800, Jiapeng Chong wrote:
> cur_state and new_state are enums and when GCC considers
> them as unsigned, the conditions are never met.
>
> Clean up the following smatch warning:
>
> drivers/infiniband/hw/mlx4/qp.c:4258 mlx4_ib_modify_wq() warn: unsigned
> 'cur_state' is never less than zero.
>
> Reported-by: Abaci Robot <[email protected]>
> Signed-off-by: Jiapeng Chong <[email protected]>
> ---
> drivers/infiniband/hw/mlx4/qp.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
> index 92ddbcc..162aa59 100644
> --- a/drivers/infiniband/hw/mlx4/qp.c
> +++ b/drivers/infiniband/hw/mlx4/qp.c
> @@ -4255,8 +4255,7 @@ int mlx4_ib_modify_wq(struct ib_wq *ibwq, struct ib_wq_attr *wq_attr,
> ibwq->state;
> new_state = wq_attr_mask & IB_WQ_STATE ? wq_attr->wq_state : cur_state;
>
> - if (cur_state < IB_WQS_RESET || cur_state > IB_WQS_ERR ||
> - new_state < IB_WQS_RESET || new_state > IB_WQS_ERR)
> + if (cur_state > IB_WQS_ERR || new_state > IB_WQS_ERR)
> return -EINVAL;

Actually the more robust change will be to move this change to the ib_uverbs_ex_modify_wq().

Thanks

>
> if ((new_state == IB_WQS_RDY) && (cur_state == IB_WQS_ERR))
> --
> 1.8.3.1
>

2021-05-11 17:46:21

by Jason Gunthorpe

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Subject: Re: [PATCH] RDMA/mlx4: Remove unnessesary check in mlx4_ib_modify_wq()

On Fri, May 07, 2021 at 06:22:41PM +0800, Jiapeng Chong wrote:
> cur_state and new_state are enums and when GCC considers
> them as unsigned, the conditions are never met.

But doesn't gcc consider enums to be 'int' as the standard requires?

This change looks really sketchy to me, cur_state and new_state are
both userspace controlled data. We should not make assumptions about
the underlying signedness of an enum when validating user data.

Jason

2021-05-19 15:45:51

by Leon Romanovsky

[permalink] [raw]
Subject: Re: [PATCH] RDMA/mlx4: Remove unnessesary check in mlx4_ib_modify_wq()

On Tue, May 11, 2021 at 02:43:02PM -0300, Jason Gunthorpe wrote:
> On Fri, May 07, 2021 at 06:22:41PM +0800, Jiapeng Chong wrote:
> > cur_state and new_state are enums and when GCC considers
> > them as unsigned, the conditions are never met.
>
> But doesn't gcc consider enums to be 'int' as the standard requires?

Ohh, I missed that.

>
> This change looks really sketchy to me, cur_state and new_state are
> both userspace controlled data. We should not make assumptions about
> the underlying signedness of an enum when validating user data.

I still think that the right change should be in
ib_uverbs_ex_modify_wq(), so both mlx4 and mlx5 will be protected.

Thanks

>
> Jason