2019-03-19 15:56:52

by Aditya Pakki

Subject: [PATCH v3] net: mlx5: Add a missing check on idr_find, free buf

idr_find() can return a NULL value to 'flow' which is used without a check.
The patch adds a check to avoid potential NULL pointer dereference.
In case of mlx5_fpga_sbu_conn_sendmsg() failure, free buf allocated
using kzalloc.

---
v2: failure to return in case of flow failure.
v1: Failed to free buf in case of flow failure.

Signed-off-by: Aditya Pakki <[email protected]>
---
drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
index 5cf5f2a9d51f..224e0d7f6489 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
@@ -226,6 +226,11 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
rcu_read_lock();
flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
rcu_read_unlock();
+ if (!flow) {
+ WARN_ONCE(1, "Received NULL pointer for handle\n");
+ kfree(buf);
+ return -EINVAL;
+ }
mlx5_fpga_tls_flow_to_cmd(flow, cmd);

MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
@@ -238,6 +243,8 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
buf->complete = mlx_tls_kfree_complete;

ret = mlx5_fpga_sbu_conn_sendmsg(mdev->fpga->tls->conn, buf);
+ if (ret < 0)
+ kfree(buf);

return ret;
}
--
2.17.1

2019-03-19 16:04:34

by Eric Dumazet

Subject: Re: [PATCH v3] net: mlx5: Add a missing check on idr_find, free buf

On 03/19/2019 08:55 AM, Aditya Pakki wrote:
> idr_find() can return a NULL value to 'flow' which is used without a check.
> The patch adds a check to avoid potential NULL pointer dereference.
> In case of mlx5_fpga_sbu_conn_sendmsg() failure, free buf allocated
> using kzalloc.
>
> ---
> v2: failure to return in case of flow failure.
> v1: Failed to free buf in case of flow failure.
>
> Signed-off-by: Aditya Pakki <[email protected]>


Please add an appropriate Fixes: tag, thanks.

2019-03-19 16:05:44

by Yuval Shaia

Subject: Re: [PATCH v3] net: mlx5: Add a missing check on idr_find, free buf

On Tue, Mar 19, 2019 at 10:55:20AM -0500, Aditya Pakki wrote:
> idr_find() can return a NULL value to 'flow' which is used without a check.
> The patch adds a check to avoid potential NULL pointer dereference.
> In case of mlx5_fpga_sbu_conn_sendmsg() failure, free buf allocated
> using kzalloc.
>
> ---
> v2: failure to return in case of flow failure.
> v1: Failed to free buf in case of flow failure.
>
> Signed-off-by: Aditya Pakki <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> index 5cf5f2a9d51f..224e0d7f6489 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> @@ -226,6 +226,11 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
> rcu_read_lock();
> flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
> rcu_read_unlock();
> + if (!flow) {
> + WARN_ONCE(1, "Received NULL pointer for handle\n");
> + kfree(buf);
> + return -EINVAL;
> + }
> mlx5_fpga_tls_flow_to_cmd(flow, cmd);
>
> MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
> @@ -238,6 +243,8 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
> buf->complete = mlx_tls_kfree_complete;
>
> ret = mlx5_fpga_sbu_conn_sendmsg(mdev->fpga->tls->conn, buf);
> + if (ret < 0)
> + kfree(buf);
>
> return ret;

Reviewed-by: Yuval Shaia <[email protected]>

> }
> --
> 2.17.1
>

2019-03-19 16:58:57

by Saeed Mahameed

Subject: Re: [PATCH v3] net: mlx5: Add a missing check on idr_find, free buf

On Tue, 2019-03-19 at 10:55 -0500, Aditya Pakki wrote:
> idr_find() can return a NULL value to 'flow' which is used without a
> check.
> The patch adds a check to avoid potential NULL pointer dereference.
> In case of mlx5_fpga_sbu_conn_sendmsg() failure, free buf allocated
> using kzalloc.
>
> ---
> v2: failure to return in case of flow failure.
> v1: Failed to free buf in case of flow failure.
>
> Signed-off-by: Aditya Pakki <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> index 5cf5f2a9d51f..224e0d7f6489 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
> @@ -226,6 +226,11 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev
> *mdev, u32 handle, u32 seq,
> rcu_read_lock();
> flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
> rcu_read_unlock();
> + if (!flow) {
> + WARN_ONCE(1, "Received NULL pointer for handle\n");
> + kfree(buf);
> + return -EINVAL;
> + }

Just a small nit, it would have been simpler if you just changed the
order between buf = kzalloc(...) and flow = idr_find, to avoid
kfree(buf) on err flow.

Please add the fixes tag as Eric suggested.

> mlx5_fpga_tls_flow_to_cmd(flow, cmd);
>
> MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
> @@ -238,6 +243,8 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev
> *mdev, u32 handle, u32 seq,
> buf->complete = mlx_tls_kfree_complete;
>
> ret = mlx5_fpga_sbu_conn_sendmsg(mdev->fpga->tls->conn, buf);
> + if (ret < 0)
> + kfree(buf);
>
> return ret;
> }