net/tls: Fix inverted error codes to avoid endless loop

sendfile() calls can hang endless with using Kernel TLS if a socket error occurs.
Socket error codes must be inverted by Kernel TLS before returning because
they are stored with positive sign. If returned non-inverted they are
interpreted as number of bytes sent, causing endless looping of the
splice mechanic behind sendfile().

Signed-off-by: Robert Hering <r.hering@avm.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Raubato

include/net/tls.h

@@ -170,7 +170,7 @@ static inline bool tls_is_pending_open_record(struct tls_context *tls_ctx)
 
 static inline void tls_err_abort(struct sock *sk)
 {
-	sk->sk_err = -EBADMSG;
+	sk->sk_err = EBADMSG;
 	sk->sk_error_report(sk);
 }
 

net/tls/tls_sw.c

@@ -391,7 +391,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 
 	while (msg_data_left(msg)) {
 		if (sk->sk_err) {
-			ret = sk->sk_err;
+			ret = -sk->sk_err;
 			goto send_end;
 		}
 
@@ -544,7 +544,7 @@ int tls_sw_sendpage(struct sock *sk, struct page *page,
 		size_t copy, required_size;
 
 		if (sk->sk_err) {
-			ret = sk->sk_err;
+			ret = -sk->sk_err;
 			goto sendpage_end;
 		}