2020-12-21 08:53:31

by Dinghao Liu

Subject: [PATCH] net/mlx5e: Fix two double free cases

mlx5e_create_ttc_table_groups() frees ft->g on failure of
kvzalloc(), but such failure will be caught by its caller
in mlx5e_create_ttc_table() and ft->g will be freed again
in mlx5e_destroy_flow_table(). The same issue also occurs
in mlx5e_create_ttc_table_groups().

Signed-off-by: Dinghao Liu <[email protected]>
---
drivers/net/ethernet/mellanox/mlx5/core/en_fs.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
index fa8149f6eb08..63323c5b6a50 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
@@ -940,10 +940,8 @@ static int mlx5e_create_ttc_table_groups(struct mlx5e_ttc_table *ttc,
if (!ft->g)
return -ENOMEM;
in = kvzalloc(inlen, GFP_KERNEL);
- if (!in) {
- kfree(ft->g);
+ if (!in)
return -ENOMEM;
- }

/* L4 Group */
mc = MLX5_ADDR_OF(create_flow_group_in, in, match_criteria);
@@ -1085,10 +1083,8 @@ static int mlx5e_create_inner_ttc_table_groups(struct mlx5e_ttc_table *ttc)
if (!ft->g)
return -ENOMEM;
in = kvzalloc(inlen, GFP_KERNEL);
- if (!in) {
- kfree(ft->g);
+ if (!in)
return -ENOMEM;
- }

/* L4 Group */
mc = MLX5_ADDR_OF(create_flow_group_in, in, match_criteria);
--
2.17.1

2020-12-27 08:41:38

by Leon Romanovsky

Subject: Re: [PATCH] net/mlx5e: Fix two double free cases

On Mon, Dec 21, 2020 at 04:50:31PM +0800, Dinghao Liu wrote:
> mlx5e_create_ttc_table_groups() frees ft->g on failure of
> kvzalloc(), but such failure will be caught by its caller
> in mlx5e_create_ttc_table() and ft->g will be freed again
> in mlx5e_destroy_flow_table(). The same issue also occurs
> in mlx5e_create_ttc_table_groups().
>
> Signed-off-by: Dinghao Liu <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/en_fs.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)

I'm not thrilled to see release in the error flow that will be done in
the different function. The missing piece is "ft->g = NULL" after kfree().

And also fixes lines are missing in all your patches.

Thanks

2020-12-28 03:16:05

by Dinghao Liu

Subject: Re: Re: [PATCH] net/mlx5e: Fix two double free cases

> On Mon, Dec 21, 2020 at 04:50:31PM +0800, Dinghao Liu wrote:
> > mlx5e_create_ttc_table_groups() frees ft->g on failure of
> > kvzalloc(), but such failure will be caught by its caller
> > in mlx5e_create_ttc_table() and ft->g will be freed again
> > in mlx5e_destroy_flow_table(). The same issue also occurs
> > in mlx5e_create_ttc_table_groups().
> >
> > Signed-off-by: Dinghao Liu <[email protected]>
> > ---
> > drivers/net/ethernet/mellanox/mlx5/core/en_fs.c | 8 ++------
> > 1 file changed, 2 insertions(+), 6 deletions(-)
>
> I'm not thrilled to see release in the error flow that will be done in
> the different function. The missing piece is "ft->g = NULL" after kfree().
>
> And also fixes lines are missing in all your patches.
>

Thank you for your advice! I will resend a new patch soon.

Regards,
Dinghao