From: Maxim Mikityanskiy maximmi@mellanox.com
[ Upstream commit b850bbff965129c34f50962638c0a66c82563536 ]
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: 0419d8c9d8f8 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- .../mellanox/mlx5/core/en_accel/ktls_rx.c | 64 +++++++++---------- 1 file changed, 30 insertions(+), 34 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c index 0f13b661f7f98..d06532d0baa43 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c @@ -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); }