Re: [PATCH v2] net/mlx5: Fix use-after-free

[Saeed Mahameed]

On Thu, 2018-03-22 at 13:44 -0500, Gustavo A. R. Silva wrote:
> _rule_ is being freed and then dereferenced by accessing rule->ctx
> 
> Fix this by copying the value returned by PTR_ERR(rule->ctx) into a
> local
> variable for its safe use after freeing _rule_
> 
> Addresses-Coverity-ID: 1466041 ("Read from pointer after free")
> Fixes: 05564d0ae075 ("net/mlx5: Add flow-steering commands for FPGA
> IPSec implementation")
> Reviewed-by: Yuval Shaia <yuval.shaia@xxxxxxxxxx>
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

Acked-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>

> ---
> Changes in v2:
>  - Use a short subject prefix as suggested by Yuval Shaia.
>  - Add Yuval's Reviewed-by.
> 
>  drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c
> b/drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c
> index 4f15685..0f5da49 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c
> @@ -1061,8 +1061,9 @@ static int fpga_ipsec_fs_create_fte(struct
> mlx5_core_dev *dev,
>  
>  	rule->ctx = mlx5_fpga_ipsec_fs_create_sa_ctx(dev, fte,
> is_egress);
>  	if (IS_ERR(rule->ctx)) {
> +		int err = PTR_ERR(rule->ctx);
>  		kfree(rule);
> -		return PTR_ERR(rule->ctx);
> +		return err;
>  	}
>  
>  	rule->fte = fte;