net/handshake: Add API for sending TLS Closure alerts

This helper sends an alert only if a TLS session was established.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/169047936730.5241.618595693821012638.stgit@oracle-102.nfsv4bat.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/handshake.h b/include/net/handshake.h
index 2e26e43..bb88dfa 100644 (file)
--- 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 247d73c..ef4d9a2 100644 (file)
--- 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 (file)
index 0000000..2f1a168
--- /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@oracle.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 4dac965..a481637 100644 (file)
--- 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 b735f5c..bbfb409 100644 (file)
--- 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);