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Date: Thu, 27 Jul 2023 13:36:17 -0400
From: Chuck Lever <cel@...nel.org>
To: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com
Cc: netdev@...r.kernel.org, kernel-tls-handshake@...ts.linux.dev
Subject: [PATCH net-next v3 3/7] net/handshake: Add API for sending TLS
Closure alerts
From: Chuck Lever <chuck.lever@...cle.com>
This helper sends an alert only if a TLS session was established.
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
---
include/net/handshake.h | 1 +
net/handshake/Makefile | 2 +
net/handshake/alert.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
net/handshake/handshake.h | 6 ++++
net/handshake/tlshd.c | 23 +++++++++++++++++
5 files changed, 92 insertions(+), 1 deletion(-)
create mode 100644 net/handshake/alert.c
diff --git a/include/net/handshake.h b/include/net/handshake.h
index 2e26e436e85f..bb88dfa6e3c9 100644
--- a/include/net/handshake.h
+++ b/include/net/handshake.h
@@ -40,5 +40,6 @@ int tls_server_hello_x509(const struct tls_handshake_args *args, gfp_t flags);
int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags);
bool tls_handshake_cancel(struct sock *sk);
+void tls_handshake_close(struct socket *sock);
#endif /* _NET_HANDSHAKE_H */
diff --git a/net/handshake/Makefile b/net/handshake/Makefile
index 247d73c6ff6e..ef4d9a2112bd 100644
--- a/net/handshake/Makefile
+++ b/net/handshake/Makefile
@@ -8,6 +8,6 @@
#
obj-y += handshake.o
-handshake-y := genl.o netlink.o request.o tlshd.o trace.o
+handshake-y := alert.o genl.o netlink.o request.o tlshd.o trace.o
obj-$(CONFIG_NET_HANDSHAKE_KUNIT_TEST) += handshake-test.o
diff --git a/net/handshake/alert.c b/net/handshake/alert.c
new file mode 100644
index 000000000000..2f1a16868ff6
--- /dev/null
+++ b/net/handshake/alert.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Handle the TLS Alert protocol
+ *
+ * Author: Chuck Lever <chuck.lever@...cle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/inet.h>
+
+#include <net/sock.h>
+#include <net/handshake.h>
+#include <net/tls.h>
+#include <net/tls_prot.h>
+
+#include "handshake.h"
+
+/**
+ * tls_alert_send - send a TLS Alert on a kTLS socket
+ * @sock: open kTLS socket to send on
+ * @level: TLS Alert level
+ * @description: TLS Alert description
+ *
+ * Returns zero on success or a negative errno.
+ */
+int tls_alert_send(struct socket *sock, u8 level, u8 description)
+{
+ u8 record_type = TLS_RECORD_TYPE_ALERT;
+ u8 buf[CMSG_SPACE(sizeof(record_type))];
+ struct msghdr msg = { 0 };
+ struct cmsghdr *cmsg;
+ struct kvec iov;
+ u8 alert[2];
+ int ret;
+
+ alert[0] = level;
+ alert[1] = description;
+ iov.iov_base = alert;
+ iov.iov_len = sizeof(alert);
+
+ memset(buf, 0, sizeof(buf));
+ msg.msg_control = buf;
+ msg.msg_controllen = sizeof(buf);
+ msg.msg_flags = MSG_DONTWAIT;
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_TLS;
+ cmsg->cmsg_type = TLS_SET_RECORD_TYPE;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(record_type));
+ memcpy(CMSG_DATA(cmsg), &record_type, sizeof(record_type));
+
+ iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, iov.iov_len);
+ ret = sock_sendmsg(sock, &msg);
+ return ret < 0 ? ret : 0;
+}
diff --git a/net/handshake/handshake.h b/net/handshake/handshake.h
index 4dac965c99df..a48163765a7a 100644
--- a/net/handshake/handshake.h
+++ b/net/handshake/handshake.h
@@ -41,8 +41,11 @@ struct handshake_req {
enum hr_flags_bits {
HANDSHAKE_F_REQ_COMPLETED,
+ HANDSHAKE_F_REQ_SESSION,
};
+struct genl_info;
+
/* Invariants for all handshake requests for one transport layer
* security protocol
*/
@@ -63,6 +66,9 @@ enum hp_flags_bits {
HANDSHAKE_F_PROTO_NOTIFY,
};
+/* alert.c */
+int tls_alert_send(struct socket *sock, u8 level, u8 description);
+
/* netlink.c */
int handshake_genl_notify(struct net *net, const struct handshake_proto *proto,
gfp_t flags);
diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
index b735f5cced2f..bbfb4095ddd6 100644
--- a/net/handshake/tlshd.c
+++ b/net/handshake/tlshd.c
@@ -18,6 +18,7 @@
#include <net/sock.h>
#include <net/handshake.h>
#include <net/genetlink.h>
+#include <net/tls_prot.h>
#include <uapi/linux/keyctl.h>
#include <uapi/linux/handshake.h>
@@ -100,6 +101,9 @@ static void tls_handshake_done(struct handshake_req *req,
if (info)
tls_handshake_remote_peerids(treq, info);
+ if (!status)
+ set_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags);
+
treq->th_consumer_done(treq->th_consumer_data, -status,
treq->th_peerid[0]);
}
@@ -424,3 +428,22 @@ bool tls_handshake_cancel(struct sock *sk)
return handshake_req_cancel(sk);
}
EXPORT_SYMBOL(tls_handshake_cancel);
+
+/**
+ * tls_handshake_close - send a Closure alert
+ * @sock: an open socket
+ *
+ */
+void tls_handshake_close(struct socket *sock)
+{
+ struct handshake_req *req;
+
+ req = handshake_req_hash_lookup(sock->sk);
+ if (!req)
+ return;
+ if (!test_and_clear_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags))
+ return;
+ tls_alert_send(sock, TLS_ALERT_LEVEL_WARNING,
+ TLS_ALERT_DESC_CLOSE_NOTIFY);
+}
+EXPORT_SYMBOL(tls_handshake_close);
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