alert.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Handle the TLS Alert protocol
  4 *
  5 * Author: Chuck Lever <chuck.lever@oracle.com>
  6 *
  7 * Copyright (c) 2023, Oracle and/or its affiliates.
  8 */
  9
 10#include <linux/types.h>
 11#include <linux/socket.h>
 12#include <linux/kernel.h>
 13#include <linux/module.h>
 14#include <linux/skbuff.h>
 15#include <linux/inet.h>
 16
 17#include <net/sock.h>
 18#include <net/handshake.h>
 19#include <net/tls.h>
 20#include <net/tls_prot.h>
 21
 22#include "handshake.h"
 23
 24#include <trace/events/handshake.h>
 25
 26/**
 27 * tls_alert_send - send a TLS Alert on a kTLS socket
 28 * @sock: open kTLS socket to send on
 29 * @level: TLS Alert level
 30 * @description: TLS Alert description
 31 *
 32 * Returns zero on success or a negative errno.
 33 */
 34int tls_alert_send(struct socket *sock, u8 level, u8 description)
 35{
 36	u8 record_type = TLS_RECORD_TYPE_ALERT;
 37	u8 buf[CMSG_SPACE(sizeof(record_type))];
 38	struct msghdr msg = { 0 };
 39	struct cmsghdr *cmsg;
 40	struct kvec iov;
 41	u8 alert[2];
 42	int ret;
 43
 44	trace_tls_alert_send(sock->sk, level, description);
 45
 46	alert[0] = level;
 47	alert[1] = description;
 48	iov.iov_base = alert;
 49	iov.iov_len = sizeof(alert);
 50
 51	memset(buf, 0, sizeof(buf));
 52	msg.msg_control = buf;
 53	msg.msg_controllen = sizeof(buf);
 54	msg.msg_flags = MSG_DONTWAIT;
 55
 56	cmsg = CMSG_FIRSTHDR(&msg);
 57	cmsg->cmsg_level = SOL_TLS;
 58	cmsg->cmsg_type = TLS_SET_RECORD_TYPE;
 59	cmsg->cmsg_len = CMSG_LEN(sizeof(record_type));
 60	memcpy(CMSG_DATA(cmsg), &record_type, sizeof(record_type));
 61
 62	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, iov.iov_len);
 63	ret = sock_sendmsg(sock, &msg);
 64	return ret < 0 ? ret : 0;
 65}
 66
 67/**
 68 * tls_get_record_type - Look for TLS RECORD_TYPE information
 69 * @sk: socket (for IP address information)
 70 * @cmsg: incoming message to be parsed
 71 *
 72 * Returns zero or a TLS_RECORD_TYPE value.
 73 */
 74u8 tls_get_record_type(const struct sock *sk, const struct cmsghdr *cmsg)
 75{
 76	u8 record_type;
 77
 78	if (cmsg->cmsg_level != SOL_TLS)
 79		return 0;
 80	if (cmsg->cmsg_type != TLS_GET_RECORD_TYPE)
 81		return 0;
 82
 83	record_type = *((u8 *)CMSG_DATA(cmsg));
 84	trace_tls_contenttype(sk, record_type);
 85	return record_type;
 86}
 87EXPORT_SYMBOL(tls_get_record_type);
 88
 89/**
 90 * tls_alert_recv - Parse TLS Alert messages
 91 * @sk: socket (for IP address information)
 92 * @msg: incoming message to be parsed
 93 * @level: OUT - TLS AlertLevel value
 94 * @description: OUT - TLS AlertDescription value
 95 *
 96 */
 97void tls_alert_recv(const struct sock *sk, const struct msghdr *msg,
 98		    u8 *level, u8 *description)
 99{
100	const struct kvec *iov;
101	u8 *data;
102
103	iov = msg->msg_iter.kvec;
104	data = iov->iov_base;
105	*level = data[0];
106	*description = data[1];
107
108	trace_tls_alert_recv(sk, *level, *description);
109}
110EXPORT_SYMBOL(tls_alert_recv);