net/tls: make sure offload also gets the keys wiped

Commit 86029d10af ("tls: zero the crypto information from tls_context
before freeing") added memzero_explicit() calls to clear the key material
before freeing struct tls_context, but it missed tls_device.c has its
own way of freeing this structure. Replace the missing free.

Fixes: 86029d10af ("tls: zero the crypto information from tls_context before freeing")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -313,6 +313,7 @@ struct tls_offload_context_rx {
 	(ALIGN(sizeof(struct tls_offload_context_rx), sizeof(void *)) + \
 	 TLS_DRIVER_STATE_SIZE)
 
+void tls_ctx_free(struct tls_context *ctx);
 int wait_on_pending_writer(struct sock *sk, long *timeo);
 int tls_sk_query(struct sock *sk, int optname, char __user *optval,
 		int __user *optlen);

net/tls/tls_device.c

@@ -61,7 +61,7 @@ static void tls_device_free_ctx(struct tls_context *ctx)
 	if (ctx->rx_conf == TLS_HW)
 		kfree(tls_offload_ctx_rx(ctx));
 
-	kfree(ctx);
+	tls_ctx_free(ctx);
 }
 
 static void tls_device_gc_task(struct work_struct *work)

net/tls/tls_main.c

@@ -251,7 +251,7 @@ static void tls_write_space(struct sock *sk)
 	ctx->sk_write_space(sk);
 }
 
-static void tls_ctx_free(struct tls_context *ctx)
+void tls_ctx_free(struct tls_context *ctx)
 {
 	if (!ctx)
 		return;
@@ -643,7 +643,7 @@ static void tls_hw_sk_destruct(struct sock *sk)
 
 	ctx->sk_destruct(sk);
 	/* Free ctx */
-	kfree(ctx);
+	tls_ctx_free(ctx);
 	icsk->icsk_ulp_data = NULL;
 }