netdev - [PATCH net 1/2] net/tls: Protect from calling tls_dev

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Date:   Tue, 17 Nov 2020 12:33:54 -0800
From:   Saeed Mahameed <saeedm@...dia.com>
To:     Jakub Kicinski <kuba@...nel.org>
CC:     <netdev@...r.kernel.org>, "David S. Miller" <davem@...emloft.net>,
        "Maxim Mikityanskiy" <maximmi@...lanox.com>,
        Saeed Mahameed <saeedm@...dia.com>
Subject: [PATCH net 1/2] net/tls: Protect from calling tls_dev_del for TLS RX twice

From: Maxim Mikityanskiy <maximmi@...lanox.com>

tls_device_offload_cleanup_rx doesn't clear tls_ctx->netdev after
calling tls_dev_del if TLX TX offload is also enabled. Clearing
tls_ctx->netdev gets postponed until tls_device_gc_task. It leaves a
time frame when tls_device_down may get called and call tls_dev_del for
RX one extra time, confusing the driver, which may lead to a crash.

This patch corrects this racy behavior by adding a flag to prevent
tls_device_down from calling tls_dev_del the second time.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Maxim Mikityanskiy <maximmi@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
For -stable: 5.3

 include/net/tls.h    | 1 +
 net/tls/tls_device.c | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/net/tls.h b/include/net/tls.h
index baf1e99d8193..a0deddfde412 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -199,6 +199,7 @@ enum tls_context_flags {
 	 * to be atomic.
 	 */
 	TLS_TX_SYNC_SCHED = 1,
+	TLS_RX_DEV_RELEASED = 2,
 };
 
 struct cipher_context {
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index cec86229a6a0..b2261caac6be 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -1241,6 +1241,7 @@ void tls_device_offload_cleanup_rx(struct sock *sk)
 
 	netdev->tlsdev_ops->tls_dev_del(netdev, tls_ctx,
 					TLS_OFFLOAD_CTX_DIR_RX);
+	set_bit(TLS_RX_DEV_RELEASED, &tls_ctx->flags);
 
 	if (tls_ctx->tx_conf != TLS_HW) {
 		dev_put(netdev);
@@ -1274,7 +1275,7 @@ static int tls_device_down(struct net_device *netdev)
 		if (ctx->tx_conf == TLS_HW)
 			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
 							TLS_OFFLOAD_CTX_DIR_TX);
-		if (ctx->rx_conf == TLS_HW)
+		if (ctx->rx_conf == TLS_HW && !test_bit(TLS_RX_DEV_RELEASED, &ctx->flags))
 			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
 							TLS_OFFLOAD_CTX_DIR_RX);
 		WRITE_ONCE(ctx->netdev, NULL);
-- 
2.26.2