1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Establish a TLS session for a kernel socket consumer
4 * using the tlshd user space handler.
5 *
6 * Author: Chuck Lever <chuck.lever@oracle.com>
7 *
8 * Copyright (c) 2021-2023, Oracle and/or its affiliates.
9 */
10
11#include <linux/types.h>
12#include <linux/socket.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/key.h>
17
18#include <net/sock.h>
19#include <net/handshake.h>
20#include <net/genetlink.h>
21#include <net/tls_prot.h>
22
23#include <uapi/linux/keyctl.h>
24#include <uapi/linux/handshake.h>
25#include "handshake.h"
26
27struct tls_handshake_req {
28 void (*th_consumer_done)(void *data, int status,
29 key_serial_t peerid);
30 void *th_consumer_data;
31
32 int th_type;
33 unsigned int th_timeout_ms;
34 int th_auth_mode;
35 const char *th_peername;
36 key_serial_t th_keyring;
37 key_serial_t th_certificate;
38 key_serial_t th_privkey;
39
40 unsigned int th_num_peerids;
41 key_serial_t th_peerid[5];
42};
43
44static struct tls_handshake_req *
45tls_handshake_req_init(struct handshake_req *req,
46 const struct tls_handshake_args *args)
47{
48 struct tls_handshake_req *treq = handshake_req_private(req);
49
50 treq->th_timeout_ms = args->ta_timeout_ms;
51 treq->th_consumer_done = args->ta_done;
52 treq->th_consumer_data = args->ta_data;
53 treq->th_peername = args->ta_peername;
54 treq->th_keyring = args->ta_keyring;
55 treq->th_num_peerids = 0;
56 treq->th_certificate = TLS_NO_CERT;
57 treq->th_privkey = TLS_NO_PRIVKEY;
58 return treq;
59}
60
61static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,
62 struct genl_info *info)
63{
64 struct nlattr *head = nlmsg_attrdata(nlh: info->nlhdr, GENL_HDRLEN);
65 int rem, len = nlmsg_attrlen(nlh: info->nlhdr, GENL_HDRLEN);
66 struct nlattr *nla;
67 unsigned int i;
68
69 i = 0;
70 nla_for_each_attr(nla, head, len, rem) {
71 if (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)
72 i++;
73 }
74 if (!i)
75 return;
76 treq->th_num_peerids = min_t(unsigned int, i,
77 ARRAY_SIZE(treq->th_peerid));
78
79 i = 0;
80 nla_for_each_attr(nla, head, len, rem) {
81 if (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)
82 treq->th_peerid[i++] = nla_get_u32(nla);
83 if (i >= treq->th_num_peerids)
84 break;
85 }
86}
87
88/**
89 * tls_handshake_done - callback to handle a CMD_DONE request
90 * @req: socket on which the handshake was performed
91 * @status: session status code
92 * @info: full results of session establishment
93 *
94 */
95static void tls_handshake_done(struct handshake_req *req,
96 unsigned int status, struct genl_info *info)
97{
98 struct tls_handshake_req *treq = handshake_req_private(req);
99
100 treq->th_peerid[0] = TLS_NO_PEERID;
101 if (info)
102 tls_handshake_remote_peerids(treq, info);
103
104 if (!status)
105 set_bit(nr: HANDSHAKE_F_REQ_SESSION, addr: &req->hr_flags);
106
107 treq->th_consumer_done(treq->th_consumer_data, -status,
108 treq->th_peerid[0]);
109}
110
111#if IS_ENABLED(CONFIG_KEYS)
112static int tls_handshake_private_keyring(struct tls_handshake_req *treq)
113{
114 key_ref_t process_keyring_ref, keyring_ref;
115 int ret;
116
117 if (treq->th_keyring == TLS_NO_KEYRING)
118 return 0;
119
120 process_keyring_ref = lookup_user_key(KEY_SPEC_PROCESS_KEYRING,
121 flags: KEY_LOOKUP_CREATE,
122 need_perm: KEY_NEED_WRITE);
123 if (IS_ERR(ptr: process_keyring_ref)) {
124 ret = PTR_ERR(ptr: process_keyring_ref);
125 goto out;
126 }
127
128 keyring_ref = lookup_user_key(id: treq->th_keyring, flags: KEY_LOOKUP_CREATE,
129 need_perm: KEY_NEED_LINK);
130 if (IS_ERR(ptr: keyring_ref)) {
131 ret = PTR_ERR(ptr: keyring_ref);
132 goto out_put_key;
133 }
134
135 ret = key_link(keyring: key_ref_to_ptr(key_ref: process_keyring_ref),
136 key: key_ref_to_ptr(key_ref: keyring_ref));
137
138 key_ref_put(key_ref: keyring_ref);
139out_put_key:
140 key_ref_put(key_ref: process_keyring_ref);
141out:
142 return ret;
143}
144#else
145static int tls_handshake_private_keyring(struct tls_handshake_req *treq)
146{
147 return 0;
148}
149#endif
150
151static int tls_handshake_put_peer_identity(struct sk_buff *msg,
152 struct tls_handshake_req *treq)
153{
154 unsigned int i;
155
156 for (i = 0; i < treq->th_num_peerids; i++)
157 if (nla_put_u32(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_PEER_IDENTITY,
158 value: treq->th_peerid[i]) < 0)
159 return -EMSGSIZE;
160 return 0;
161}
162
163static int tls_handshake_put_certificate(struct sk_buff *msg,
164 struct tls_handshake_req *treq)
165{
166 struct nlattr *entry_attr;
167
168 if (treq->th_certificate == TLS_NO_CERT &&
169 treq->th_privkey == TLS_NO_PRIVKEY)
170 return 0;
171
172 entry_attr = nla_nest_start(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_CERTIFICATE);
173 if (!entry_attr)
174 return -EMSGSIZE;
175
176 if (nla_put_s32(skb: msg, attrtype: HANDSHAKE_A_X509_CERT,
177 value: treq->th_certificate) ||
178 nla_put_s32(skb: msg, attrtype: HANDSHAKE_A_X509_PRIVKEY,
179 value: treq->th_privkey)) {
180 nla_nest_cancel(skb: msg, start: entry_attr);
181 return -EMSGSIZE;
182 }
183
184 nla_nest_end(skb: msg, start: entry_attr);
185 return 0;
186}
187
188/**
189 * tls_handshake_accept - callback to construct a CMD_ACCEPT response
190 * @req: handshake parameters to return
191 * @info: generic netlink message context
192 * @fd: file descriptor to be returned
193 *
194 * Returns zero on success, or a negative errno on failure.
195 */
196static int tls_handshake_accept(struct handshake_req *req,
197 struct genl_info *info, int fd)
198{
199 struct tls_handshake_req *treq = handshake_req_private(req);
200 struct nlmsghdr *hdr;
201 struct sk_buff *msg;
202 int ret;
203
204 ret = tls_handshake_private_keyring(treq);
205 if (ret < 0)
206 goto out;
207
208 ret = -ENOMEM;
209 msg = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
210 if (!msg)
211 goto out;
212 hdr = handshake_genl_put(msg, info);
213 if (!hdr)
214 goto out_cancel;
215
216 ret = -EMSGSIZE;
217 ret = nla_put_s32(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_SOCKFD, value: fd);
218 if (ret < 0)
219 goto out_cancel;
220 ret = nla_put_u32(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_MESSAGE_TYPE, value: treq->th_type);
221 if (ret < 0)
222 goto out_cancel;
223 if (treq->th_peername) {
224 ret = nla_put_string(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_PEERNAME,
225 str: treq->th_peername);
226 if (ret < 0)
227 goto out_cancel;
228 }
229 if (treq->th_timeout_ms) {
230 ret = nla_put_u32(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_TIMEOUT, value: treq->th_timeout_ms);
231 if (ret < 0)
232 goto out_cancel;
233 }
234
235 ret = nla_put_u32(skb: msg, attrtype: HANDSHAKE_A_ACCEPT_AUTH_MODE,
236 value: treq->th_auth_mode);
237 if (ret < 0)
238 goto out_cancel;
239 switch (treq->th_auth_mode) {
240 case HANDSHAKE_AUTH_PSK:
241 ret = tls_handshake_put_peer_identity(msg, treq);
242 if (ret < 0)
243 goto out_cancel;
244 break;
245 case HANDSHAKE_AUTH_X509:
246 ret = tls_handshake_put_certificate(msg, treq);
247 if (ret < 0)
248 goto out_cancel;
249 break;
250 }
251
252 genlmsg_end(skb: msg, hdr);
253 return genlmsg_reply(skb: msg, info);
254
255out_cancel:
256 genlmsg_cancel(skb: msg, hdr);
257out:
258 return ret;
259}
260
261static const struct handshake_proto tls_handshake_proto = {
262 .hp_handler_class = HANDSHAKE_HANDLER_CLASS_TLSHD,
263 .hp_privsize = sizeof(struct tls_handshake_req),
264 .hp_flags = BIT(HANDSHAKE_F_PROTO_NOTIFY),
265
266 .hp_accept = tls_handshake_accept,
267 .hp_done = tls_handshake_done,
268};
269
270/**
271 * tls_client_hello_anon - request an anonymous TLS handshake on a socket
272 * @args: socket and handshake parameters for this request
273 * @flags: memory allocation control flags
274 *
275 * Return values:
276 * %0: Handshake request enqueue; ->done will be called when complete
277 * %-ESRCH: No user agent is available
278 * %-ENOMEM: Memory allocation failed
279 */
280int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags)
281{
282 struct tls_handshake_req *treq;
283 struct handshake_req *req;
284
285 req = handshake_req_alloc(proto: &tls_handshake_proto, flags);
286 if (!req)
287 return -ENOMEM;
288 treq = tls_handshake_req_init(req, args);
289 treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;
290 treq->th_auth_mode = HANDSHAKE_AUTH_UNAUTH;
291
292 return handshake_req_submit(sock: args->ta_sock, req, flags);
293}
294EXPORT_SYMBOL(tls_client_hello_anon);
295
296/**
297 * tls_client_hello_x509 - request an x.509-based TLS handshake on a socket
298 * @args: socket and handshake parameters for this request
299 * @flags: memory allocation control flags
300 *
301 * Return values:
302 * %0: Handshake request enqueue; ->done will be called when complete
303 * %-ESRCH: No user agent is available
304 * %-ENOMEM: Memory allocation failed
305 */
306int tls_client_hello_x509(const struct tls_handshake_args *args, gfp_t flags)
307{
308 struct tls_handshake_req *treq;
309 struct handshake_req *req;
310
311 req = handshake_req_alloc(proto: &tls_handshake_proto, flags);
312 if (!req)
313 return -ENOMEM;
314 treq = tls_handshake_req_init(req, args);
315 treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;
316 treq->th_auth_mode = HANDSHAKE_AUTH_X509;
317 treq->th_certificate = args->ta_my_cert;
318 treq->th_privkey = args->ta_my_privkey;
319
320 return handshake_req_submit(sock: args->ta_sock, req, flags);
321}
322EXPORT_SYMBOL(tls_client_hello_x509);
323
324/**
325 * tls_client_hello_psk - request a PSK-based TLS handshake on a socket
326 * @args: socket and handshake parameters for this request
327 * @flags: memory allocation control flags
328 *
329 * Return values:
330 * %0: Handshake request enqueue; ->done will be called when complete
331 * %-EINVAL: Wrong number of local peer IDs
332 * %-ESRCH: No user agent is available
333 * %-ENOMEM: Memory allocation failed
334 */
335int tls_client_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
336{
337 struct tls_handshake_req *treq;
338 struct handshake_req *req;
339 unsigned int i;
340
341 if (!args->ta_num_peerids ||
342 args->ta_num_peerids > ARRAY_SIZE(treq->th_peerid))
343 return -EINVAL;
344
345 req = handshake_req_alloc(proto: &tls_handshake_proto, flags);
346 if (!req)
347 return -ENOMEM;
348 treq = tls_handshake_req_init(req, args);
349 treq->th_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;
350 treq->th_auth_mode = HANDSHAKE_AUTH_PSK;
351 treq->th_num_peerids = args->ta_num_peerids;
352 for (i = 0; i < args->ta_num_peerids; i++)
353 treq->th_peerid[i] = args->ta_my_peerids[i];
354
355 return handshake_req_submit(sock: args->ta_sock, req, flags);
356}
357EXPORT_SYMBOL(tls_client_hello_psk);
358
359/**
360 * tls_server_hello_x509 - request a server TLS handshake on a socket
361 * @args: socket and handshake parameters for this request
362 * @flags: memory allocation control flags
363 *
364 * Return values:
365 * %0: Handshake request enqueue; ->done will be called when complete
366 * %-ESRCH: No user agent is available
367 * %-ENOMEM: Memory allocation failed
368 */
369int tls_server_hello_x509(const struct tls_handshake_args *args, gfp_t flags)
370{
371 struct tls_handshake_req *treq;
372 struct handshake_req *req;
373
374 req = handshake_req_alloc(proto: &tls_handshake_proto, flags);
375 if (!req)
376 return -ENOMEM;
377 treq = tls_handshake_req_init(req, args);
378 treq->th_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;
379 treq->th_auth_mode = HANDSHAKE_AUTH_X509;
380 treq->th_certificate = args->ta_my_cert;
381 treq->th_privkey = args->ta_my_privkey;
382
383 return handshake_req_submit(sock: args->ta_sock, req, flags);
384}
385EXPORT_SYMBOL(tls_server_hello_x509);
386
387/**
388 * tls_server_hello_psk - request a server TLS handshake on a socket
389 * @args: socket and handshake parameters for this request
390 * @flags: memory allocation control flags
391 *
392 * Return values:
393 * %0: Handshake request enqueue; ->done will be called when complete
394 * %-ESRCH: No user agent is available
395 * %-ENOMEM: Memory allocation failed
396 */
397int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags)
398{
399 struct tls_handshake_req *treq;
400 struct handshake_req *req;
401
402 req = handshake_req_alloc(proto: &tls_handshake_proto, flags);
403 if (!req)
404 return -ENOMEM;
405 treq = tls_handshake_req_init(req, args);
406 treq->th_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;
407 treq->th_auth_mode = HANDSHAKE_AUTH_PSK;
408 treq->th_num_peerids = 1;
409 treq->th_peerid[0] = args->ta_my_peerids[0];
410
411 return handshake_req_submit(sock: args->ta_sock, req, flags);
412}
413EXPORT_SYMBOL(tls_server_hello_psk);
414
415/**
416 * tls_handshake_cancel - cancel a pending handshake
417 * @sk: socket on which there is an ongoing handshake
418 *
419 * Request cancellation races with request completion. To determine
420 * who won, callers examine the return value from this function.
421 *
422 * Return values:
423 * %true - Uncompleted handshake request was canceled
424 * %false - Handshake request already completed or not found
425 */
426bool tls_handshake_cancel(struct sock *sk)
427{
428 return handshake_req_cancel(sk);
429}
430EXPORT_SYMBOL(tls_handshake_cancel);
431
432/**
433 * tls_handshake_close - send a Closure alert
434 * @sock: an open socket
435 *
436 */
437void tls_handshake_close(struct socket *sock)
438{
439 struct handshake_req *req;
440
441 req = handshake_req_hash_lookup(sk: sock->sk);
442 if (!req)
443 return;
444 if (!test_and_clear_bit(nr: HANDSHAKE_F_REQ_SESSION, addr: &req->hr_flags))
445 return;
446 tls_alert_send(sock, level: TLS_ALERT_LEVEL_WARNING,
447 description: TLS_ALERT_DESC_CLOSE_NOTIFY);
448}
449EXPORT_SYMBOL(tls_handshake_close);
450

source code of linux/net/handshake/tlshd.c