2022-02-24 22:38:03

by Colin Ian King

Subject: [PATCH] net/mlx5e: Fix return of a kfree'd object instead of NULL

Currently in the case where parse_attr fails to be allocated the memory
pointed to by attr2 is kfree'd but the non-null pointer attr2 is returned
and a potential use of a kfree'd object can occur. Fix this by returning
NULL to indicate a memory allocation error.

Addresses issue found by clang-scan:
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:3401:3: warning: Use of
memory after it is freed [unix.Malloc]

Fixes: 8300f225268b ("net/mlx5e: Create new flow attr for multi table actions")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 76a015dfc5fc..c0776a4a3845 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -3398,7 +3398,7 @@ mlx5e_clone_flow_attr_for_post_act(struct mlx5_flow_attr *attr,
if (!attr2 || !parse_attr) {
kvfree(parse_attr);
kfree(attr2);
- return attr2;
+ return NULL;
}

memcpy(attr2, attr, attr_sz);
--
2.34.1

2022-02-25 12:43:29

by Roi Dayan

Subject: Re: [PATCH] net/mlx5e: Fix return of a kfree'd object instead of NULL

On 2022-02-25 12:15 AM, Colin Ian King wrote:
> Currently in the case where parse_attr fails to be allocated the memory
> pointed to by attr2 is kfree'd but the non-null pointer attr2 is returned
> and a potential use of a kfree'd object can occur. Fix this by returning
> NULL to indicate a memory allocation error.
>
> Addresses issue found by clang-scan:
> drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:3401:3: warning: Use of
> memory after it is freed [unix.Malloc]
>
> Fixes: 8300f225268b ("net/mlx5e: Create new flow attr for multi table actions")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> index 76a015dfc5fc..c0776a4a3845 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> @@ -3398,7 +3398,7 @@ mlx5e_clone_flow_attr_for_post_act(struct mlx5_flow_attr *attr,
> if (!attr2 || !parse_attr) {
> kvfree(parse_attr);
> kfree(attr2);
> - return attr2;
> + return NULL;
> }
>
> memcpy(attr2, attr, attr_sz);


thanks!

Reviewed-by: Roi Dayan <[email protected]>

2022-03-01 08:39:30

by Saeed Mahameed

Subject: Re: [PATCH] net/mlx5e: Fix return of a kfree'd object instead of NULL

On 24 Feb 22:15, Colin Ian King wrote:
>Currently in the case where parse_attr fails to be allocated the memory
>pointed to by attr2 is kfree'd but the non-null pointer attr2 is returned
>and a potential use of a kfree'd object can occur. Fix this by returning
>NULL to indicate a memory allocation error.
>
>Addresses issue found by clang-scan:
>drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:3401:3: warning: Use of
>memory after it is freed [unix.Malloc]
>
>Fixes: 8300f225268b ("net/mlx5e: Create new flow attr for multi table actions")
>Signed-off-by: Colin Ian King <[email protected]>
Applied to net-next-mlx5
Thanks.