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net/mlx5e: kTLS, Use refcounts to free kTLS RX priv context 

wait_for_resync is unreliable - if it timeouts, priv_rx will be freed
anyway. However, mlx5e_ktls_handle_get_psv_completion will be called
sooner or later, leading to use-after-free. For example, it can happen
if a CQ error happened, and ICOSQ stopped, but later on the queues are
destroyed, and ICOSQ is flushed with mlx5e_free_icosq_descs.

This patch converts the lifecycle of priv_rx to fully refcount-based, so
that the struct won't be freed before the refcount goes to zero.

Fixes: 0419d8c9d8 ("net/mlx5e: kTLS, Add kTLS RX resync support")
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
This commit is contained in:
Maxim Mikityanskiy 2021-01-22 18:42:29 +02:00 committed by Saeed Mahameed
parent ebf79b6be6
commit b850bbff96
1 changed files with 30 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c
View File

@ -57,6 +57,20 @@ struct mlx5e_ktls_offload_context_rx {
struct mlx5e_ktls_rx_resync_ctx resync;
};
static bool mlx5e_ktls_priv_rx_put(struct mlx5e_ktls_offload_context_rx *priv_rx)
{
if (!refcount_dec_and_test(&priv_rx->resync.refcnt))
return false;
kfree(priv_rx);
return true;
}
static void mlx5e_ktls_priv_rx_get(struct mlx5e_ktls_offload_context_rx *priv_rx)
{
refcount_inc(&priv_rx->resync.refcnt);
}
static int mlx5e_ktls_create_tir(struct mlx5_core_dev *mdev, u32 *tirn, u32 rqtn)
{
int err, inlen;
@ -326,7 +340,7 @@ static void resync_handle_work(struct work_struct *work)
priv_rx = container_of(resync, struct mlx5e_ktls_offload_context_rx, resync);
if (unlikely(test_bit(MLX5E_PRIV_RX_FLAG_DELETING, priv_rx->flags))) {
refcount_dec(&resync->refcnt);
mlx5e_ktls_priv_rx_put(priv_rx);
return;
}
@ -334,7 +348,7 @@ static void resync_handle_work(struct work_struct *work)
sq = &c->async_icosq;
if (resync_post_get_progress_params(sq, priv_rx))
refcount_dec(&resync->refcnt);
mlx5e_ktls_priv_rx_put(priv_rx);
}
static void resync_init(struct mlx5e_ktls_rx_resync_ctx *resync,
@ -377,7 +391,11 @@ unlock:
return err;
}
/* Function is called with elevated refcount, it decreases it. */
/* Function can be called with the refcount being either elevated or not.
* It decreases the refcount and may free the kTLS priv context.
* Refcount is not elevated only if tls_dev_del has been called, but GET_PSV was
* already in flight.
*/
void mlx5e_ktls_handle_get_psv_completion(struct mlx5e_icosq_wqe_info *wi,
struct mlx5e_icosq *sq)
{
@ -410,7 +428,7 @@ void mlx5e_ktls_handle_get_psv_completion(struct mlx5e_icosq_wqe_info *wi,
tls_offload_rx_resync_async_request_end(priv_rx->sk, cpu_to_be32(hw_seq));
priv_rx->stats->tls_resync_req_end++;
out:
refcount_dec(&resync->refcnt);
mlx5e_ktls_priv_rx_put(priv_rx);
dma_unmap_single(dev, buf->dma_addr, PROGRESS_PARAMS_PADDED_SIZE, DMA_FROM_DEVICE);
kfree(buf);
}
@ -431,9 +449,9 @@ static bool resync_queue_get_psv(struct sock *sk)
return false;
resync = &priv_rx->resync;
refcount_inc(&resync->refcnt);
mlx5e_ktls_priv_rx_get(priv_rx);
if (unlikely(!queue_work(resync->priv->tls->rx_wq, &resync->work)))
refcount_dec(&resync->refcnt);
mlx5e_ktls_priv_rx_put(priv_rx);
return true;
}
@ -625,31 +643,6 @@ err_create_key:
return err;
}
/* Elevated refcount on the resync object means there are
* outstanding operations (uncompleted GET_PSV WQEs) that
* will read the resync / priv_rx objects once completed.
* Wait for them to avoid use-after-free.
*/
static void wait_for_resync(struct net_device *netdev,
struct mlx5e_ktls_rx_resync_ctx *resync)
{
#define MLX5E_KTLS_RX_RESYNC_TIMEOUT 20000 /* msecs */
unsigned long exp_time = jiffies + msecs_to_jiffies(MLX5E_KTLS_RX_RESYNC_TIMEOUT);
unsigned int refcnt;
do {
refcnt = refcount_read(&resync->refcnt);
if (refcnt == 1)
return;
msleep(20);
} while (time_before(jiffies, exp_time));
netdev_warn(netdev,
"Failed waiting for kTLS RX resync refcnt to be released (%u).\n",
refcnt);
}
void mlx5e_ktls_del_rx(struct net_device *netdev, struct tls_context *tls_ctx)
{
struct mlx5e_ktls_offload_context_rx *priv_rx;
@ -671,8 +664,7 @@ void mlx5e_ktls_del_rx(struct net_device *netdev, struct tls_context *tls_ctx)
wait_for_completion(&priv_rx->add_ctx);
resync = &priv_rx->resync;
if (cancel_work_sync(&resync->work))
refcount_dec(&resync->refcnt);
wait_for_resync(netdev, resync);
mlx5e_ktls_priv_rx_put(priv_rx);
priv_rx->stats->tls_del++;
if (priv_rx->rule.rule)
@ -680,5 +672,9 @@ void mlx5e_ktls_del_rx(struct net_device *netdev, struct tls_context *tls_ctx)
mlx5_core_destroy_tir(mdev, priv_rx->tirn);
mlx5_ktls_destroy_key(mdev, priv_rx->key_id);
kfree(priv_rx);
/* priv_rx should normally be freed here, but if there is an outstanding
* GET_PSV, deallocation will be delayed until the CQE for GET_PSV is
* processed.
*/
mlx5e_ktls_priv_rx_put(priv_rx);
}