net/tls: don't leak partially sent record in device mode

David reports that tls triggers warnings related to
sk->sk_forward_alloc not being zero at destruction time:

WARNING: CPU: 5 PID: 6831 at net/core/stream.c:206 sk_stream_kill_queues+0x103/0x110
WARNING: CPU: 5 PID: 6831 at net/ipv4/af_inet.c:160 inet_sock_destruct+0x15b/0x170

When sender fills up the write buffer and dies from
SIGPIPE.  This is due to the device implementation
not cleaning up the partially_sent_record.

This is because commit a42055e8d2 ("net/tls: Add support for async encryption of records for performance")
moved the partial record cleanup to the SW-only path.

Fixes: a42055e8d2 ("net/tls: Add support for async encryption of records for performance")
Reported-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -307,6 +307,7 @@ int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
 int tls_device_sendpage(struct sock *sk, struct page *page,
 			int offset, size_t size, int flags);
 void tls_device_sk_destruct(struct sock *sk);
+void tls_device_free_resources_tx(struct sock *sk);
 void tls_device_init(void);
 void tls_device_cleanup(void);
 int tls_tx_records(struct sock *sk, int flags);
@@ -330,6 +331,7 @@ int tls_push_sg(struct sock *sk, struct tls_context *ctx,
 		int flags);
 int tls_push_partial_record(struct sock *sk, struct tls_context *ctx,
 			    int flags);
+bool tls_free_partial_record(struct sock *sk, struct tls_context *ctx);
 
 static inline struct tls_msg *tls_msg(struct sk_buff *skb)
 {

net/tls/tls_device.c

@@ -219,6 +219,13 @@ void tls_device_sk_destruct(struct sock *sk)
 }
 EXPORT_SYMBOL(tls_device_sk_destruct);
 
+void tls_device_free_resources_tx(struct sock *sk)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+
+	tls_free_partial_record(sk, tls_ctx);
+}
+
 static void tls_append_frag(struct tls_record_info *record,
 			    struct page_frag *pfrag,
 			    int size)

net/tls/tls_main.c

@@ -208,6 +208,26 @@ int tls_push_partial_record(struct sock *sk, struct tls_context *ctx,
 	return tls_push_sg(sk, ctx, sg, offset, flags);
 }
 
+bool tls_free_partial_record(struct sock *sk, struct tls_context *ctx)
+{
+	struct scatterlist *sg;
+
+	sg = ctx->partially_sent_record;
+	if (!sg)
+		return false;
+
+	while (1) {
+		put_page(sg_page(sg));
+		sk_mem_uncharge(sk, sg->length);
+
+		if (sg_is_last(sg))
+			break;
+		sg++;
+	}
+	ctx->partially_sent_record = NULL;
+	return true;
+}
+
 static void tls_write_space(struct sock *sk)
 {
 	struct tls_context *ctx = tls_get_ctx(sk);
@@ -267,6 +287,8 @@ static void tls_sk_proto_close(struct sock *sk, long timeout)
 		kfree(ctx->tx.rec_seq);
 		kfree(ctx->tx.iv);
 		tls_sw_free_resources_tx(sk);
+	} else if (ctx->tx_conf == TLS_HW) {
+		tls_device_free_resources_tx(sk);
 	}
 
 	if (ctx->rx_conf == TLS_SW) {

net/tls/tls_sw.c

@@ -2052,20 +2052,7 @@ void tls_sw_free_resources_tx(struct sock *sk)
 	/* Free up un-sent records in tx_list. First, free
 	 * the partially sent record if any at head of tx_list.
 	 */
-	if (tls_ctx->partially_sent_record) {
+	if (tls_free_partial_record(sk, tls_ctx)) {
-		struct scatterlist *sg = tls_ctx->partially_sent_record;
-
-		while (1) {
-			put_page(sg_page(sg));
-			sk_mem_uncharge(sk, sg->length);
-
-			if (sg_is_last(sg))
-				break;
-			sg++;
-		}
-
-		tls_ctx->partially_sent_record = NULL;
-
 		rec = list_first_entry(&ctx->tx_list,
 				       struct tls_rec, list);
 		list_del(&rec->list);