Re: [PATCH 2/3] RDMA/mlx5: Invoke fw_validate_cmd LSM hook for DEVX commands

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Mon,  9 Mar 2026 13:15:19 +0200
Leon Romanovsky <leon@kernel.org> wrote:

> From: Chiara Meiohas <cmeiohas@nvidia.com>
> 
> DEVX is an RDMA uverbs extension that allows userspace to submit
> firmware command buffers. The driver inspects the command and then
> passes the buffer through for firmware execution.
> 
> Call security_fw_validate_cmd() before dispatching firmware commands
> through DEVX.
> 
> This allows security modules to implement custom policies and
> enforce per-command security policy on user-triggered firmware
> commands. For example, a BPF LSM program could restrict specific
> firmware operations to privileged users.
> 
> Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com>
> Reviewed-by: Maher Sanalla <msanalla@nvidia.com>
> Signed-off-by: Edward Srouji <edwards@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
A few formatting inconsistencies.  Actual code is fine as far as I can tell.
So given I don't know the driver, take this as vague at best...

Assuming formatting stuff tidied up.

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>


> ---
>  drivers/infiniband/hw/mlx5/devx.c | 52 ++++++++++++++++++++++++++++++---------
>  1 file changed, 40 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
> index 0066b2738ac89..48a2c4b4ad4eb 100644
> --- a/drivers/infiniband/hw/mlx5/devx.c
> +++ b/drivers/infiniband/hw/mlx5/devx.c
> @@ -18,6 +18,7 @@
>  #include "devx.h"
>  #include "qp.h"
>  #include <linux/xarray.h>
> +#include <linux/security.h>
>  
>  #define UVERBS_MODULE_NAME mlx5_ib
>  #include <rdma/uverbs_named_ioctl.h>
> @@ -1111,6 +1112,8 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OTHER)(
>  	struct mlx5_ib_dev *dev;
>  	void *cmd_in = uverbs_attr_get_alloced_ptr(
>  		attrs, MLX5_IB_ATTR_DEVX_OTHER_CMD_IN);
> +	int cmd_in_len = uverbs_attr_get_len(attrs,
> +					MLX5_IB_ATTR_DEVX_OTHER_CMD_IN);
>  	int cmd_out_len = uverbs_attr_get_len(attrs,
>  					MLX5_IB_ATTR_DEVX_OTHER_CMD_OUT);
>  	void *cmd_out;
> @@ -1135,9 +1138,12 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OTHER)(
>  		return PTR_ERR(cmd_out);
>  
>  	MLX5_SET(general_obj_in_cmd_hdr, cmd_in, uid, uid);
> -	err = mlx5_cmd_do(dev->mdev, cmd_in,
> -			  uverbs_attr_get_len(attrs, MLX5_IB_ATTR_DEVX_OTHER_CMD_IN),
> -			  cmd_out, cmd_out_len);
> +	err = security_fw_validate_cmd(cmd_in, cmd_in_len, &dev->ib_dev.dev,
> +				       FW_CMD_CLASS_UVERBS, RDMA_DRIVER_MLX5);
> +	if (err)
> +		return err;
> +
> +	err = mlx5_cmd_do(dev->mdev, cmd_in, cmd_in_len, cmd_out, cmd_out_len);

See below for inconsistency on how the changes have been done.

>  	if (err && err != -EREMOTEIO)
>  		return err;
>  
> @@ -1570,6 +1576,12 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_CREATE)(
>  		devx_set_umem_valid(cmd_in);
>  	}
>  
> +	err = security_fw_validate_cmd(cmd_in, cmd_in_len,
> +				       &dev->ib_dev.dev,
> +				       FW_CMD_CLASS_UVERBS, RDMA_DRIVER_MLX5);
> +	if (err)
> +		goto obj_free;
> +
>  	if (opcode == MLX5_CMD_OP_CREATE_DCT) {
>  		obj->flags |= DEVX_OBJ_FLAGS_DCT;
>  		err = mlx5_core_create_dct(dev, &obj->core_dct, cmd_in,
> @@ -1582,8 +1594,8 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_CREATE)(
>  				     cmd_in, cmd_in_len, cmd_out,
>  				     cmd_out_len);
>  	} else {
> -		err = mlx5_cmd_do(dev->mdev, cmd_in, cmd_in_len,
> -				  cmd_out, cmd_out_len);
> +		err = mlx5_cmd_do(dev->mdev, cmd_in, cmd_in_len, cmd_out,
> +				  cmd_out_len);

Unrelated bit of reformatting. Shouldn't be in this patch.,


>  	}
>  
>  	if (err == -EREMOTEIO)
> @@ -1646,6 +1658,8 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_MODIFY)(
>  	struct uverbs_attr_bundle *attrs)
>  {
>  	void *cmd_in = uverbs_attr_get_alloced_ptr(attrs, MLX5_IB_ATTR_DEVX_OBJ_MODIFY_CMD_IN);
> +	int cmd_in_len = uverbs_attr_get_len(attrs,
> +					MLX5_IB_ATTR_DEVX_OBJ_MODIFY_CMD_IN);
>  	int cmd_out_len = uverbs_attr_get_len(attrs,
>  					MLX5_IB_ATTR_DEVX_OBJ_MODIFY_CMD_OUT);
>  	struct ib_uobject *uobj = uverbs_attr_get_uobject(attrs,
> @@ -1676,9 +1690,12 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_MODIFY)(
>  
>  	MLX5_SET(general_obj_in_cmd_hdr, cmd_in, uid, uid);
>  	devx_set_umem_valid(cmd_in);
> +	err = security_fw_validate_cmd(cmd_in, cmd_in_len, &mdev->ib_dev.dev,
> +				       FW_CMD_CLASS_UVERBS, RDMA_DRIVER_MLX5);
> +	if (err)
> +		return err;
>  
> -	err = mlx5_cmd_do(mdev->mdev, cmd_in,
> -			  uverbs_attr_get_len(attrs, MLX5_IB_ATTR_DEVX_OBJ_MODIFY_CMD_IN),
> +	err = mlx5_cmd_do(mdev->mdev, cmd_in, cmd_in_len,
>  			  cmd_out, cmd_out_len);

Similar to case above, this not fits on one line.

>  	if (err && err != -EREMOTEIO)
>  		return err;
> @@ -1693,6 +1710,8 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_QUERY)(
>  	struct uverbs_attr_bundle *attrs)
>  {
>  	void *cmd_in = uverbs_attr_get_alloced_ptr(attrs, MLX5_IB_ATTR_DEVX_OBJ_QUERY_CMD_IN);
> +	int cmd_in_len = uverbs_attr_get_len(attrs,
> +					     MLX5_IB_ATTR_DEVX_OBJ_QUERY_CMD_IN);
>  	int cmd_out_len = uverbs_attr_get_len(attrs,
>  					      MLX5_IB_ATTR_DEVX_OBJ_QUERY_CMD_OUT);
>  	struct ib_uobject *uobj = uverbs_attr_get_uobject(attrs,
> @@ -1722,8 +1741,12 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_QUERY)(
>  		return PTR_ERR(cmd_out);
>  
>  	MLX5_SET(general_obj_in_cmd_hdr, cmd_in, uid, uid);
> -	err = mlx5_cmd_do(mdev->mdev, cmd_in,
> -			  uverbs_attr_get_len(attrs, MLX5_IB_ATTR_DEVX_OBJ_QUERY_CMD_IN),
> +	err = security_fw_validate_cmd(cmd_in, cmd_in_len, &mdev->ib_dev.dev,
> +				       FW_CMD_CLASS_UVERBS, RDMA_DRIVER_MLX5);
> +	if (err)
> +		return err;
> +
> +	err = mlx5_cmd_do(mdev->mdev, cmd_in, cmd_in_len,
>  			  cmd_out, cmd_out_len);

As above.

>  	if (err && err != -EREMOTEIO)
>  		return err;
> @@ -1832,6 +1855,8 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY)(
>  {
>  	void *cmd_in = uverbs_attr_get_alloced_ptr(attrs,
>  				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_CMD_IN);
> +	int cmd_in_len = uverbs_attr_get_len(attrs,
> +				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_CMD_IN);
>  	struct ib_uobject *uobj = uverbs_attr_get_uobject(
>  				attrs,
>  				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_HANDLE);
> @@ -1894,9 +1919,12 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY)(
>  	async_data->ev_file = ev_file;
>  
>  	MLX5_SET(general_obj_in_cmd_hdr, cmd_in, uid, uid);
> -	err = mlx5_cmd_exec_cb(&ev_file->async_ctx, cmd_in,
> -		    uverbs_attr_get_len(attrs,
> -				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_CMD_IN),
> +	err = security_fw_validate_cmd(cmd_in, cmd_in_len, &mdev->ib_dev.dev,
> +				       FW_CMD_CLASS_UVERBS, RDMA_DRIVER_MLX5);
> +	if (err)
> +		goto free_async;
> +
> +	err = mlx5_cmd_exec_cb(&ev_file->async_ctx, cmd_in, cmd_in_len,
>  		    async_data->hdr.out_data,
>  		    async_data->cmd_out_len,
>  		    devx_query_callback, &async_data->cb_work);
>