linux-stable/net/handshake/tlshd.c
Chuck Lever 35b1b538d4 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>
2023-07-28 14:07:59 -07:00

449 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Establish a TLS session for a kernel socket consumer
* using the tlshd user space handler.
*
* Author: Chuck Lever <chuck.lever@oracle.com>
*
* Copyright (c) 2021-2023, Oracle and/or its affiliates.
*/
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/key.h>
#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>
#include "handshake.h"
struct tls_handshake_req {
void (*th_consumer_done)(void *data, int status,
key_serial_t peerid);
void *th_consumer_data;
int th_type;
unsigned int th_timeout_ms;
int th_auth_mode;
const char *th_peername;
key_serial_t th_keyring;
key_serial_t th_certificate;
key_serial_t th_privkey;
unsigned int th_num_peerids;
key_serial_t th_peerid[5];
};
static struct tls_handshake_req *
tls_handshake_req_init(struct handshake_req *req,
const struct tls_handshake_args *args)
{
struct tls_handshake_req *treq = handshake_req_private(req);
treq->th_timeout_ms = args->ta_timeout_ms;
treq->th_consumer_done = args->ta_done;
treq->th_consumer_data = args->ta_data;
treq->th_peername = args->ta_peername;
treq->th_keyring = args->ta_keyring;
treq->th_num_peerids = 0;
treq->th_certificate = TLS_NO_CERT;
treq->th_privkey = TLS_NO_PRIVKEY;
return treq;
}
static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,
struct genl_info *info)
{
struct nlattr *head = nlmsg_attrdata(info->nlhdr, GENL_HDRLEN);
int rem, len = nlmsg_attrlen(info->nlhdr, GENL_HDRLEN);
struct nlattr *nla;
unsigned int i;
i = 0;
nla_for_each_attr(nla, head, len, rem) {
if (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)
i++;
}
if (!i)
return;
treq->th_num_peerids = min_t(unsigned int, i,
ARRAY_SIZE(treq->th_peerid));
i = 0;
nla_for_each_attr(nla, head, len, rem) {
if (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)
treq->th_peerid[i++] = nla_get_u32(nla);
if (i >= treq->th_num_peerids)
break;
}
}
/**
* tls_handshake_done - callback to handle a CMD_DONE request
* @req: socket on which the handshake was performed
* @status: session status code
* @info: full results of session establishment
*
*/
static void tls_handshake_done(struct handshake_req *req,
unsigned int status, struct genl_info *info)
{
struct tls_handshake_req *treq = handshake_req_private(req);
treq->th_peerid[0] = TLS_NO_PEERID;
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]);
}
#if IS_ENABLED(CONFIG_KEYS)
static int tls_handshake_private_keyring(struct tls_handshake_req *treq)
{
key_ref_t process_keyring_ref, keyring_ref;
int ret;
if (treq->th_keyring == TLS_NO_KEYRING)
return 0;
process_keyring_ref = lookup_user_key(KEY_SPEC_PROCESS_KEYRING,
KEY_LOOKUP_CREATE,
KEY_NEED_WRITE);
if (IS_ERR(process_keyring_ref)) {
ret = PTR_ERR(process_keyring_ref);
goto out;
}
keyring_ref = lookup_user_key(treq->th_keyring, KEY_LOOKUP_CREATE,
KEY_NEED_LINK);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto out_put_key;
}
ret = key_link(key_ref_to_ptr(process_keyring_ref),
key_ref_to_ptr(keyring_ref));
key_ref_put(keyring_ref);
out_put_key:
key_ref_put(process_keyring_ref);
out:
return ret;
}
#else
static int tls_handshake_private_keyring(struct tls_handshake_req *treq)
{
return 0;
}
#endif
static int tls_handshake_put_peer_identity(struct sk_buff *msg,
struct tls_handshake_req *treq)
{
unsigned int i;
for (i = 0; i < treq->th_num_peerids; i++)
if (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_PEER_IDENTITY,
treq->th_peerid[i]) < 0)
return -EMSGSIZE;
return 0;
}
static int tls_handshake_put_certificate(struct sk_buff *msg,
struct tls_handshake_req *treq)
{
struct nlattr *entry_attr;
if (treq->th_certificate == TLS_NO_CERT &&
treq->th_privkey == TLS_NO_PRIVKEY)
return 0;
entry_attr = nla_nest_start(msg, HANDSHAKE_A_ACCEPT_CERTIFICATE);
if (!entry_attr)
return -EMSGSIZE;
if (nla_put_u32(msg, HANDSHAKE_A_X509_CERT,
treq->th_certificate) ||
nla_put_u32(msg, HANDSHAKE_A_X509_PRIVKEY,
treq->th_privkey)) {
nla_nest_cancel(msg, entry_attr);
return -EMSGSIZE;
}
nla_nest_end(msg, entry_attr);
return 0;
}
/**
* tls_handshake_accept - callback to construct a CMD_ACCEPT response
* @req: handshake parameters to return
* @info: generic netlink message context
* @fd: file descriptor to be returned
*
* Returns zero on success, or a negative errno on failure.
*/
static int tls_handshake_accept(struct handshake_req *req,
struct genl_info *info, int fd)
{
struct tls_handshake_req *treq = handshake_req_private(req);
struct nlmsghdr *hdr;
struct sk_buff *msg;
int ret;
ret = tls_handshake_private_keyring(treq);
if (ret < 0)
goto out;
ret = -ENOMEM;
msg = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
goto out;
hdr = handshake_genl_put(msg, info);
if (!hdr)
goto out_cancel;
ret = -EMSGSIZE;
ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_SOCKFD, fd);
if (ret < 0)
goto out_cancel;
ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_MESSAGE_TYPE, treq->th_type);
if (ret < 0)
goto out_cancel;
if (treq->th_peername) {
ret = nla_put_string(msg, HANDSHAKE_A_ACCEPT_PEERNAME,
treq->th_peername);
if (ret < 0)
goto out_cancel;
}
if (treq->th_timeout_ms) {
ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_TIMEOUT, treq->th_timeout_ms);
if (ret < 0)
goto out_cancel;
}
ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_AUTH_MODE,
treq->th_auth_mode);
if (ret < 0)
goto out_cancel;
switch (treq->th_auth_mode) {
case HANDSHAKE_AUTH_PSK:
ret = tls_handshake_put_peer_identity(msg, treq);
if (ret < 0)
goto out_cancel;
break;
case HANDSHAKE_AUTH_X509:
ret = tls_handshake_put_certificate(msg, treq);
if (ret < 0)
goto out_cancel;
break;
}
genlmsg_end(msg, hdr);
return genlmsg_reply(msg, info);
out_cancel:
genlmsg_cancel(msg, hdr);
out:
return ret;
}
static const struct handshake_proto tls_handshake_proto = {
.hp_handler_class = HANDSHAKE_HANDLER_CLASS_TLSHD,
.hp_privsize = sizeof(struct tls_handshake_req),
.hp_flags = BIT(HANDSHAKE_F_PROTO_NOTIFY),
.hp_accept = tls_handshake_accept,
.hp_done = tls_handshake_done,
};
/**
* tls_client_hello_anon - request an anonymous TLS handshake on a socket
* @args: socket and handshake parameters for this request
* @flags: memory allocation control flags
*
* Return values:
* %0: Handshake request enqueue; ->done will be called when complete
* %-ESRCH: No user agent is available
* %-ENOMEM: Memory allocation failed
*/
int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags)
{
struct tls_handshake_req *treq;
struct handshake_req *req;
req = handshake_req_alloc(&tls_handshake_proto, flags);
if (!req)
return -ENOMEM;
treq = tls_handshake_req_init(req, args);
treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;
treq->th_auth_mode = HANDSHAKE_AUTH_UNAUTH;
return handshake_req_submit(args->ta_sock, req, flags);
}
EXPORT_SYMBOL(tls_client_hello_anon);
/**
* tls_client_hello_x509 - request an x.509-based TLS handshake on a socket
* @args: socket and handshake parameters for this request
* @flags: memory allocation control flags
*
* Return values:
* %0: Handshake request enqueue; ->done will be called when complete
* %-ESRCH: No user agent is available
* %-ENOMEM: Memory allocation failed
*/
int tls_client_hello_x509(const struct tls_handshake_args *args, gfp_t flags)
{
struct tls_handshake_req *treq;
struct handshake_req *req;
req = handshake_req_alloc(&tls_handshake_proto, flags);
if (!req)
return -ENOMEM;
treq = tls_handshake_req_init(req, args);
treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;
treq->th_auth_mode = HANDSHAKE_AUTH_X509;
treq->th_certificate = args->ta_my_cert;
treq->th_privkey = args->ta_my_privkey;
return handshake_req_submit(args->ta_sock, req, flags);
}
EXPORT_SYMBOL(tls_client_hello_x509);
/**
* tls_client_hello_psk - request a PSK-based TLS handshake on a socket
* @args: socket and handshake parameters for this request
* @flags: memory allocation control flags
*
* Return values:
* %0: Handshake request enqueue; ->done will be called when complete
* %-EINVAL: Wrong number of local peer IDs
* %-ESRCH: No user agent is available
* %-ENOMEM: Memory allocation failed
*/
int tls_client_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
{
struct tls_handshake_req *treq;
struct handshake_req *req;
unsigned int i;
if (!args->ta_num_peerids ||
args->ta_num_peerids > ARRAY_SIZE(treq->th_peerid))
return -EINVAL;
req = handshake_req_alloc(&tls_handshake_proto, flags);
if (!req)
return -ENOMEM;
treq = tls_handshake_req_init(req, args);
treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;
treq->th_auth_mode = HANDSHAKE_AUTH_PSK;
treq->th_num_peerids = args->ta_num_peerids;
for (i = 0; i < args->ta_num_peerids; i++)
treq->th_peerid[i] = args->ta_my_peerids[i];
return handshake_req_submit(args->ta_sock, req, flags);
}
EXPORT_SYMBOL(tls_client_hello_psk);
/**
* tls_server_hello_x509 - request a server TLS handshake on a socket
* @args: socket and handshake parameters for this request
* @flags: memory allocation control flags
*
* Return values:
* %0: Handshake request enqueue; ->done will be called when complete
* %-ESRCH: No user agent is available
* %-ENOMEM: Memory allocation failed
*/
int tls_server_hello_x509(const struct tls_handshake_args *args, gfp_t flags)
{
struct tls_handshake_req *treq;
struct handshake_req *req;
req = handshake_req_alloc(&tls_handshake_proto, flags);
if (!req)
return -ENOMEM;
treq = tls_handshake_req_init(req, args);
treq->th_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;
treq->th_auth_mode = HANDSHAKE_AUTH_X509;
treq->th_certificate = args->ta_my_cert;
treq->th_privkey = args->ta_my_privkey;
return handshake_req_submit(args->ta_sock, req, flags);
}
EXPORT_SYMBOL(tls_server_hello_x509);
/**
* tls_server_hello_psk - request a server TLS handshake on a socket
* @args: socket and handshake parameters for this request
* @flags: memory allocation control flags
*
* Return values:
* %0: Handshake request enqueue; ->done will be called when complete
* %-ESRCH: No user agent is available
* %-ENOMEM: Memory allocation failed
*/
int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
{
struct tls_handshake_req *treq;
struct handshake_req *req;
req = handshake_req_alloc(&tls_handshake_proto, flags);
if (!req)
return -ENOMEM;
treq = tls_handshake_req_init(req, args);
treq->th_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;
treq->th_auth_mode = HANDSHAKE_AUTH_PSK;
treq->th_num_peerids = 1;
treq->th_peerid[0] = args->ta_my_peerids[0];
return handshake_req_submit(args->ta_sock, req, flags);
}
EXPORT_SYMBOL(tls_server_hello_psk);
/**
* tls_handshake_cancel - cancel a pending handshake
* @sk: socket on which there is an ongoing handshake
*
* Request cancellation races with request completion. To determine
* who won, callers examine the return value from this function.
*
* Return values:
* %true - Uncompleted handshake request was canceled
* %false - Handshake request already completed or not found
*/
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);