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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Management Component Transport Protocol (MCTP)
4  *
5  * Copyright (c) 2021 Code Construct
6  * Copyright (c) 2021 Google
7  */
8 
9 #include <linux/compat.h>
10 #include <linux/if_arp.h>
11 #include <linux/net.h>
12 #include <linux/mctp.h>
13 #include <linux/module.h>
14 #include <linux/socket.h>
15 
16 #include <net/mctp.h>
17 #include <net/mctpdevice.h>
18 #include <net/sock.h>
19 
20 #define CREATE_TRACE_POINTS
21 #include <trace/events/mctp.h>
22 
23 /* socket implementation */
24 
25 static void mctp_sk_expire_keys(struct timer_list *timer);
26 
mctp_release(struct socket * sock)27 static int mctp_release(struct socket *sock)
28 {
29 	struct sock *sk = sock->sk;
30 
31 	if (sk) {
32 		sock->sk = NULL;
33 		sk->sk_prot->close(sk, 0);
34 	}
35 
36 	return 0;
37 }
38 
39 /* Generic sockaddr checks, padding checks only so far */
mctp_sockaddr_is_ok(const struct sockaddr_mctp * addr)40 static bool mctp_sockaddr_is_ok(const struct sockaddr_mctp *addr)
41 {
42 	return !addr->__smctp_pad0 && !addr->__smctp_pad1;
43 }
44 
mctp_sockaddr_ext_is_ok(const struct sockaddr_mctp_ext * addr)45 static bool mctp_sockaddr_ext_is_ok(const struct sockaddr_mctp_ext *addr)
46 {
47 	return !addr->__smctp_pad0[0] &&
48 	       !addr->__smctp_pad0[1] &&
49 	       !addr->__smctp_pad0[2];
50 }
51 
mctp_bind(struct socket * sock,struct sockaddr * addr,int addrlen)52 static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen)
53 {
54 	struct sock *sk = sock->sk;
55 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
56 	struct sockaddr_mctp *smctp;
57 	int rc;
58 
59 	if (addrlen < sizeof(*smctp))
60 		return -EINVAL;
61 
62 	if (addr->sa_family != AF_MCTP)
63 		return -EAFNOSUPPORT;
64 
65 	if (!capable(CAP_NET_BIND_SERVICE))
66 		return -EACCES;
67 
68 	/* it's a valid sockaddr for MCTP, cast and do protocol checks */
69 	smctp = (struct sockaddr_mctp *)addr;
70 
71 	if (!mctp_sockaddr_is_ok(smctp))
72 		return -EINVAL;
73 
74 	lock_sock(sk);
75 
76 	if (sk_hashed(sk)) {
77 		rc = -EADDRINUSE;
78 		goto out_release;
79 	}
80 	msk->bind_net = smctp->smctp_network;
81 	msk->bind_addr = smctp->smctp_addr.s_addr;
82 	msk->bind_type = smctp->smctp_type & 0x7f; /* ignore the IC bit */
83 
84 	rc = sk->sk_prot->hash(sk);
85 
86 out_release:
87 	release_sock(sk);
88 
89 	return rc;
90 }
91 
mctp_sendmsg(struct socket * sock,struct msghdr * msg,size_t len)92 static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
93 {
94 	DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name);
95 	int rc, addrlen = msg->msg_namelen;
96 	struct sock *sk = sock->sk;
97 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
98 	struct mctp_skb_cb *cb;
99 	struct mctp_route *rt;
100 	struct sk_buff *skb = NULL;
101 	int hlen;
102 
103 	if (addr) {
104 		const u8 tagbits = MCTP_TAG_MASK | MCTP_TAG_OWNER |
105 			MCTP_TAG_PREALLOC;
106 
107 		if (addrlen < sizeof(struct sockaddr_mctp))
108 			return -EINVAL;
109 		if (addr->smctp_family != AF_MCTP)
110 			return -EINVAL;
111 		if (!mctp_sockaddr_is_ok(addr))
112 			return -EINVAL;
113 		if (addr->smctp_tag & ~tagbits)
114 			return -EINVAL;
115 		/* can't preallocate a non-owned tag */
116 		if (addr->smctp_tag & MCTP_TAG_PREALLOC &&
117 		    !(addr->smctp_tag & MCTP_TAG_OWNER))
118 			return -EINVAL;
119 
120 	} else {
121 		/* TODO: connect()ed sockets */
122 		return -EDESTADDRREQ;
123 	}
124 
125 	if (!capable(CAP_NET_RAW))
126 		return -EACCES;
127 
128 	if (addr->smctp_network == MCTP_NET_ANY)
129 		addr->smctp_network = mctp_default_net(sock_net(sk));
130 
131 	/* direct addressing */
132 	if (msk->addr_ext && addrlen >= sizeof(struct sockaddr_mctp_ext)) {
133 		DECLARE_SOCKADDR(struct sockaddr_mctp_ext *,
134 				 extaddr, msg->msg_name);
135 		struct net_device *dev;
136 
137 		rc = -EINVAL;
138 		rcu_read_lock();
139 		dev = dev_get_by_index_rcu(sock_net(sk), extaddr->smctp_ifindex);
140 		/* check for correct halen */
141 		if (dev && extaddr->smctp_halen == dev->addr_len) {
142 			hlen = LL_RESERVED_SPACE(dev) + sizeof(struct mctp_hdr);
143 			rc = 0;
144 		}
145 		rcu_read_unlock();
146 		if (rc)
147 			goto err_free;
148 		rt = NULL;
149 	} else {
150 		rt = mctp_route_lookup(sock_net(sk), addr->smctp_network,
151 				       addr->smctp_addr.s_addr);
152 		if (!rt) {
153 			rc = -EHOSTUNREACH;
154 			goto err_free;
155 		}
156 		hlen = LL_RESERVED_SPACE(rt->dev->dev) + sizeof(struct mctp_hdr);
157 	}
158 
159 	skb = sock_alloc_send_skb(sk, hlen + 1 + len,
160 				  msg->msg_flags & MSG_DONTWAIT, &rc);
161 	if (!skb)
162 		return rc;
163 
164 	skb_reserve(skb, hlen);
165 
166 	/* set type as fist byte in payload */
167 	*(u8 *)skb_put(skb, 1) = addr->smctp_type;
168 
169 	rc = memcpy_from_msg((void *)skb_put(skb, len), msg, len);
170 	if (rc < 0)
171 		goto err_free;
172 
173 	/* set up cb */
174 	cb = __mctp_cb(skb);
175 	cb->net = addr->smctp_network;
176 
177 	if (!rt) {
178 		/* fill extended address in cb */
179 		DECLARE_SOCKADDR(struct sockaddr_mctp_ext *,
180 				 extaddr, msg->msg_name);
181 
182 		if (!mctp_sockaddr_ext_is_ok(extaddr) ||
183 		    extaddr->smctp_halen > sizeof(cb->haddr)) {
184 			rc = -EINVAL;
185 			goto err_free;
186 		}
187 
188 		cb->ifindex = extaddr->smctp_ifindex;
189 		/* smctp_halen is checked above */
190 		cb->halen = extaddr->smctp_halen;
191 		memcpy(cb->haddr, extaddr->smctp_haddr, cb->halen);
192 	}
193 
194 	rc = mctp_local_output(sk, rt, skb, addr->smctp_addr.s_addr,
195 			       addr->smctp_tag);
196 
197 	return rc ? : len;
198 
199 err_free:
200 	kfree_skb(skb);
201 	return rc;
202 }
203 
mctp_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)204 static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
205 			int flags)
206 {
207 	DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name);
208 	struct sock *sk = sock->sk;
209 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
210 	struct sk_buff *skb;
211 	size_t msglen;
212 	u8 type;
213 	int rc;
214 
215 	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK))
216 		return -EOPNOTSUPP;
217 
218 	skb = skb_recv_datagram(sk, flags, &rc);
219 	if (!skb)
220 		return rc;
221 
222 	if (!skb->len) {
223 		rc = 0;
224 		goto out_free;
225 	}
226 
227 	/* extract message type, remove from data */
228 	type = *((u8 *)skb->data);
229 	msglen = skb->len - 1;
230 
231 	if (len < msglen)
232 		msg->msg_flags |= MSG_TRUNC;
233 	else
234 		len = msglen;
235 
236 	rc = skb_copy_datagram_msg(skb, 1, msg, len);
237 	if (rc < 0)
238 		goto out_free;
239 
240 	sock_recv_cmsgs(msg, sk, skb);
241 
242 	if (addr) {
243 		struct mctp_skb_cb *cb = mctp_cb(skb);
244 		/* TODO: expand mctp_skb_cb for header fields? */
245 		struct mctp_hdr *hdr = mctp_hdr(skb);
246 
247 		addr = msg->msg_name;
248 		addr->smctp_family = AF_MCTP;
249 		addr->__smctp_pad0 = 0;
250 		addr->smctp_network = cb->net;
251 		addr->smctp_addr.s_addr = hdr->src;
252 		addr->smctp_type = type;
253 		addr->smctp_tag = hdr->flags_seq_tag &
254 					(MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
255 		addr->__smctp_pad1 = 0;
256 		msg->msg_namelen = sizeof(*addr);
257 
258 		if (msk->addr_ext) {
259 			DECLARE_SOCKADDR(struct sockaddr_mctp_ext *, ae,
260 					 msg->msg_name);
261 			msg->msg_namelen = sizeof(*ae);
262 			ae->smctp_ifindex = cb->ifindex;
263 			ae->smctp_halen = cb->halen;
264 			memset(ae->__smctp_pad0, 0x0, sizeof(ae->__smctp_pad0));
265 			memset(ae->smctp_haddr, 0x0, sizeof(ae->smctp_haddr));
266 			memcpy(ae->smctp_haddr, cb->haddr, cb->halen);
267 		}
268 	}
269 
270 	rc = len;
271 
272 	if (flags & MSG_TRUNC)
273 		rc = msglen;
274 
275 out_free:
276 	skb_free_datagram(sk, skb);
277 	return rc;
278 }
279 
280 /* We're done with the key; invalidate, stop reassembly, and remove from lists.
281  */
__mctp_key_remove(struct mctp_sk_key * key,struct net * net,unsigned long flags,unsigned long reason)282 static void __mctp_key_remove(struct mctp_sk_key *key, struct net *net,
283 			      unsigned long flags, unsigned long reason)
284 __releases(&key->lock)
285 __must_hold(&net->mctp.keys_lock)
286 {
287 	struct sk_buff *skb;
288 
289 	trace_mctp_key_release(key, reason);
290 	skb = key->reasm_head;
291 	key->reasm_head = NULL;
292 	key->reasm_dead = true;
293 	key->valid = false;
294 	mctp_dev_release_key(key->dev, key);
295 	spin_unlock_irqrestore(&key->lock, flags);
296 
297 	if (!hlist_unhashed(&key->hlist)) {
298 		hlist_del_init(&key->hlist);
299 		hlist_del_init(&key->sklist);
300 		/* unref for the lists */
301 		mctp_key_unref(key);
302 	}
303 
304 	kfree_skb(skb);
305 }
306 
mctp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)307 static int mctp_setsockopt(struct socket *sock, int level, int optname,
308 			   sockptr_t optval, unsigned int optlen)
309 {
310 	struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk);
311 	int val;
312 
313 	if (level != SOL_MCTP)
314 		return -EINVAL;
315 
316 	if (optname == MCTP_OPT_ADDR_EXT) {
317 		if (optlen != sizeof(int))
318 			return -EINVAL;
319 		if (copy_from_sockptr(&val, optval, sizeof(int)))
320 			return -EFAULT;
321 		msk->addr_ext = val;
322 		return 0;
323 	}
324 
325 	return -ENOPROTOOPT;
326 }
327 
mctp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)328 static int mctp_getsockopt(struct socket *sock, int level, int optname,
329 			   char __user *optval, int __user *optlen)
330 {
331 	struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk);
332 	int len, val;
333 
334 	if (level != SOL_MCTP)
335 		return -EINVAL;
336 
337 	if (get_user(len, optlen))
338 		return -EFAULT;
339 
340 	if (optname == MCTP_OPT_ADDR_EXT) {
341 		if (len != sizeof(int))
342 			return -EINVAL;
343 		val = !!msk->addr_ext;
344 		if (copy_to_user(optval, &val, len))
345 			return -EFAULT;
346 		return 0;
347 	}
348 
349 	return -ENOPROTOOPT;
350 }
351 
352 /* helpers for reading/writing the tag ioc, handling compatibility across the
353  * two versions, and some basic API error checking
354  */
mctp_ioctl_tag_copy_from_user(unsigned long arg,struct mctp_ioc_tag_ctl2 * ctl,bool tagv2)355 static int mctp_ioctl_tag_copy_from_user(unsigned long arg,
356 					 struct mctp_ioc_tag_ctl2 *ctl,
357 					 bool tagv2)
358 {
359 	struct mctp_ioc_tag_ctl ctl_compat;
360 	unsigned long size;
361 	void *ptr;
362 	int rc;
363 
364 	if (tagv2) {
365 		size = sizeof(*ctl);
366 		ptr = ctl;
367 	} else {
368 		size = sizeof(ctl_compat);
369 		ptr = &ctl_compat;
370 	}
371 
372 	rc = copy_from_user(ptr, (void __user *)arg, size);
373 	if (rc)
374 		return -EFAULT;
375 
376 	if (!tagv2) {
377 		/* compat, using defaults for new fields */
378 		ctl->net = MCTP_INITIAL_DEFAULT_NET;
379 		ctl->peer_addr = ctl_compat.peer_addr;
380 		ctl->local_addr = MCTP_ADDR_ANY;
381 		ctl->flags = ctl_compat.flags;
382 		ctl->tag = ctl_compat.tag;
383 	}
384 
385 	if (ctl->flags)
386 		return -EINVAL;
387 
388 	if (ctl->local_addr != MCTP_ADDR_ANY &&
389 	    ctl->local_addr != MCTP_ADDR_NULL)
390 		return -EINVAL;
391 
392 	return 0;
393 }
394 
mctp_ioctl_tag_copy_to_user(unsigned long arg,struct mctp_ioc_tag_ctl2 * ctl,bool tagv2)395 static int mctp_ioctl_tag_copy_to_user(unsigned long arg,
396 				       struct mctp_ioc_tag_ctl2 *ctl,
397 				       bool tagv2)
398 {
399 	struct mctp_ioc_tag_ctl ctl_compat;
400 	unsigned long size;
401 	void *ptr;
402 	int rc;
403 
404 	if (tagv2) {
405 		ptr = ctl;
406 		size = sizeof(*ctl);
407 	} else {
408 		ctl_compat.peer_addr = ctl->peer_addr;
409 		ctl_compat.tag = ctl->tag;
410 		ctl_compat.flags = ctl->flags;
411 
412 		ptr = &ctl_compat;
413 		size = sizeof(ctl_compat);
414 	}
415 
416 	rc = copy_to_user((void __user *)arg, ptr, size);
417 	if (rc)
418 		return -EFAULT;
419 
420 	return 0;
421 }
422 
mctp_ioctl_alloctag(struct mctp_sock * msk,bool tagv2,unsigned long arg)423 static int mctp_ioctl_alloctag(struct mctp_sock *msk, bool tagv2,
424 			       unsigned long arg)
425 {
426 	struct net *net = sock_net(&msk->sk);
427 	struct mctp_sk_key *key = NULL;
428 	struct mctp_ioc_tag_ctl2 ctl;
429 	unsigned long flags;
430 	u8 tag;
431 	int rc;
432 
433 	rc = mctp_ioctl_tag_copy_from_user(arg, &ctl, tagv2);
434 	if (rc)
435 		return rc;
436 
437 	if (ctl.tag)
438 		return -EINVAL;
439 
440 	key = mctp_alloc_local_tag(msk, ctl.net, MCTP_ADDR_ANY,
441 				   ctl.peer_addr, true, &tag);
442 	if (IS_ERR(key))
443 		return PTR_ERR(key);
444 
445 	ctl.tag = tag | MCTP_TAG_OWNER | MCTP_TAG_PREALLOC;
446 	rc = mctp_ioctl_tag_copy_to_user(arg, &ctl, tagv2);
447 	if (rc) {
448 		unsigned long fl2;
449 		/* Unwind our key allocation: the keys list lock needs to be
450 		 * taken before the individual key locks, and we need a valid
451 		 * flags value (fl2) to pass to __mctp_key_remove, hence the
452 		 * second spin_lock_irqsave() rather than a plain spin_lock().
453 		 */
454 		spin_lock_irqsave(&net->mctp.keys_lock, flags);
455 		spin_lock_irqsave(&key->lock, fl2);
456 		__mctp_key_remove(key, net, fl2, MCTP_TRACE_KEY_DROPPED);
457 		mctp_key_unref(key);
458 		spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
459 		return rc;
460 	}
461 
462 	mctp_key_unref(key);
463 	return 0;
464 }
465 
mctp_ioctl_droptag(struct mctp_sock * msk,bool tagv2,unsigned long arg)466 static int mctp_ioctl_droptag(struct mctp_sock *msk, bool tagv2,
467 			      unsigned long arg)
468 {
469 	struct net *net = sock_net(&msk->sk);
470 	struct mctp_ioc_tag_ctl2 ctl;
471 	unsigned long flags, fl2;
472 	struct mctp_sk_key *key;
473 	struct hlist_node *tmp;
474 	int rc;
475 	u8 tag;
476 
477 	rc = mctp_ioctl_tag_copy_from_user(arg, &ctl, tagv2);
478 	if (rc)
479 		return rc;
480 
481 	/* Must be a local tag, TO set, preallocated */
482 	if ((ctl.tag & ~MCTP_TAG_MASK) != (MCTP_TAG_OWNER | MCTP_TAG_PREALLOC))
483 		return -EINVAL;
484 
485 	tag = ctl.tag & MCTP_TAG_MASK;
486 	rc = -EINVAL;
487 
488 	if (ctl.peer_addr == MCTP_ADDR_NULL)
489 		ctl.peer_addr = MCTP_ADDR_ANY;
490 
491 	spin_lock_irqsave(&net->mctp.keys_lock, flags);
492 	hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {
493 		/* we do an irqsave here, even though we know the irq state,
494 		 * so we have the flags to pass to __mctp_key_remove
495 		 */
496 		spin_lock_irqsave(&key->lock, fl2);
497 		if (key->manual_alloc &&
498 		    ctl.net == key->net &&
499 		    ctl.peer_addr == key->peer_addr &&
500 		    tag == key->tag) {
501 			__mctp_key_remove(key, net, fl2,
502 					  MCTP_TRACE_KEY_DROPPED);
503 			rc = 0;
504 		} else {
505 			spin_unlock_irqrestore(&key->lock, fl2);
506 		}
507 	}
508 	spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
509 
510 	return rc;
511 }
512 
mctp_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)513 static int mctp_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
514 {
515 	struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk);
516 	bool tagv2 = false;
517 
518 	switch (cmd) {
519 	case SIOCMCTPALLOCTAG2:
520 	case SIOCMCTPALLOCTAG:
521 		tagv2 = cmd == SIOCMCTPALLOCTAG2;
522 		return mctp_ioctl_alloctag(msk, tagv2, arg);
523 	case SIOCMCTPDROPTAG:
524 	case SIOCMCTPDROPTAG2:
525 		tagv2 = cmd == SIOCMCTPDROPTAG2;
526 		return mctp_ioctl_droptag(msk, tagv2, arg);
527 	}
528 
529 	return -EINVAL;
530 }
531 
532 #ifdef CONFIG_COMPAT
mctp_compat_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)533 static int mctp_compat_ioctl(struct socket *sock, unsigned int cmd,
534 			     unsigned long arg)
535 {
536 	void __user *argp = compat_ptr(arg);
537 
538 	switch (cmd) {
539 	/* These have compatible ptr layouts */
540 	case SIOCMCTPALLOCTAG:
541 	case SIOCMCTPDROPTAG:
542 		return mctp_ioctl(sock, cmd, (unsigned long)argp);
543 	}
544 
545 	return -ENOIOCTLCMD;
546 }
547 #endif
548 
549 static const struct proto_ops mctp_dgram_ops = {
550 	.family		= PF_MCTP,
551 	.release	= mctp_release,
552 	.bind		= mctp_bind,
553 	.connect	= sock_no_connect,
554 	.socketpair	= sock_no_socketpair,
555 	.accept		= sock_no_accept,
556 	.getname	= sock_no_getname,
557 	.poll		= datagram_poll,
558 	.ioctl		= mctp_ioctl,
559 	.gettstamp	= sock_gettstamp,
560 	.listen		= sock_no_listen,
561 	.shutdown	= sock_no_shutdown,
562 	.setsockopt	= mctp_setsockopt,
563 	.getsockopt	= mctp_getsockopt,
564 	.sendmsg	= mctp_sendmsg,
565 	.recvmsg	= mctp_recvmsg,
566 	.mmap		= sock_no_mmap,
567 #ifdef CONFIG_COMPAT
568 	.compat_ioctl	= mctp_compat_ioctl,
569 #endif
570 };
571 
mctp_sk_expire_keys(struct timer_list * timer)572 static void mctp_sk_expire_keys(struct timer_list *timer)
573 {
574 	struct mctp_sock *msk = container_of(timer, struct mctp_sock,
575 					     key_expiry);
576 	struct net *net = sock_net(&msk->sk);
577 	unsigned long next_expiry, flags, fl2;
578 	struct mctp_sk_key *key;
579 	struct hlist_node *tmp;
580 	bool next_expiry_valid = false;
581 
582 	spin_lock_irqsave(&net->mctp.keys_lock, flags);
583 
584 	hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {
585 		/* don't expire. manual_alloc is immutable, no locking
586 		 * required.
587 		 */
588 		if (key->manual_alloc)
589 			continue;
590 
591 		spin_lock_irqsave(&key->lock, fl2);
592 		if (!time_after_eq(key->expiry, jiffies)) {
593 			__mctp_key_remove(key, net, fl2,
594 					  MCTP_TRACE_KEY_TIMEOUT);
595 			continue;
596 		}
597 
598 		if (next_expiry_valid) {
599 			if (time_before(key->expiry, next_expiry))
600 				next_expiry = key->expiry;
601 		} else {
602 			next_expiry = key->expiry;
603 			next_expiry_valid = true;
604 		}
605 		spin_unlock_irqrestore(&key->lock, fl2);
606 	}
607 
608 	spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
609 
610 	if (next_expiry_valid)
611 		mod_timer(timer, next_expiry);
612 }
613 
mctp_sk_init(struct sock * sk)614 static int mctp_sk_init(struct sock *sk)
615 {
616 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
617 
618 	INIT_HLIST_HEAD(&msk->keys);
619 	timer_setup(&msk->key_expiry, mctp_sk_expire_keys, 0);
620 	return 0;
621 }
622 
mctp_sk_close(struct sock * sk,long timeout)623 static void mctp_sk_close(struct sock *sk, long timeout)
624 {
625 	sk_common_release(sk);
626 }
627 
mctp_sk_hash(struct sock * sk)628 static int mctp_sk_hash(struct sock *sk)
629 {
630 	struct net *net = sock_net(sk);
631 	struct sock *existing;
632 	struct mctp_sock *msk;
633 	int rc;
634 
635 	msk = container_of(sk, struct mctp_sock, sk);
636 
637 	/* Bind lookup runs under RCU, remain live during that. */
638 	sock_set_flag(sk, SOCK_RCU_FREE);
639 
640 	mutex_lock(&net->mctp.bind_lock);
641 
642 	/* Prevent duplicate binds. */
643 	sk_for_each(existing, &net->mctp.binds) {
644 		struct mctp_sock *mex =
645 			container_of(existing, struct mctp_sock, sk);
646 
647 		if (mex->bind_type == msk->bind_type &&
648 		    mex->bind_addr == msk->bind_addr &&
649 		    mex->bind_net == msk->bind_net) {
650 			rc = -EADDRINUSE;
651 			goto out;
652 		}
653 	}
654 
655 	sk_add_node_rcu(sk, &net->mctp.binds);
656 	rc = 0;
657 
658 out:
659 	mutex_unlock(&net->mctp.bind_lock);
660 	return rc;
661 }
662 
mctp_sk_unhash(struct sock * sk)663 static void mctp_sk_unhash(struct sock *sk)
664 {
665 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
666 	struct net *net = sock_net(sk);
667 	unsigned long flags, fl2;
668 	struct mctp_sk_key *key;
669 	struct hlist_node *tmp;
670 
671 	/* remove from any type-based binds */
672 	mutex_lock(&net->mctp.bind_lock);
673 	sk_del_node_init_rcu(sk);
674 	mutex_unlock(&net->mctp.bind_lock);
675 
676 	/* remove tag allocations */
677 	spin_lock_irqsave(&net->mctp.keys_lock, flags);
678 	hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {
679 		spin_lock_irqsave(&key->lock, fl2);
680 		__mctp_key_remove(key, net, fl2, MCTP_TRACE_KEY_CLOSED);
681 	}
682 	sock_set_flag(sk, SOCK_DEAD);
683 	spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
684 
685 	/* Since there are no more tag allocations (we have removed all of the
686 	 * keys), stop any pending expiry events. the timer cannot be re-queued
687 	 * as the sk is no longer observable
688 	 */
689 	del_timer_sync(&msk->key_expiry);
690 }
691 
mctp_sk_destruct(struct sock * sk)692 static void mctp_sk_destruct(struct sock *sk)
693 {
694 	skb_queue_purge(&sk->sk_receive_queue);
695 }
696 
697 static struct proto mctp_proto = {
698 	.name		= "MCTP",
699 	.owner		= THIS_MODULE,
700 	.obj_size	= sizeof(struct mctp_sock),
701 	.init		= mctp_sk_init,
702 	.close		= mctp_sk_close,
703 	.hash		= mctp_sk_hash,
704 	.unhash		= mctp_sk_unhash,
705 };
706 
mctp_pf_create(struct net * net,struct socket * sock,int protocol,int kern)707 static int mctp_pf_create(struct net *net, struct socket *sock,
708 			  int protocol, int kern)
709 {
710 	const struct proto_ops *ops;
711 	struct proto *proto;
712 	struct sock *sk;
713 	int rc;
714 
715 	if (protocol)
716 		return -EPROTONOSUPPORT;
717 
718 	/* only datagram sockets are supported */
719 	if (sock->type != SOCK_DGRAM)
720 		return -ESOCKTNOSUPPORT;
721 
722 	proto = &mctp_proto;
723 	ops = &mctp_dgram_ops;
724 
725 	sock->state = SS_UNCONNECTED;
726 	sock->ops = ops;
727 
728 	sk = sk_alloc(net, PF_MCTP, GFP_KERNEL, proto, kern);
729 	if (!sk)
730 		return -ENOMEM;
731 
732 	sock_init_data(sock, sk);
733 	sk->sk_destruct = mctp_sk_destruct;
734 
735 	rc = 0;
736 	if (sk->sk_prot->init)
737 		rc = sk->sk_prot->init(sk);
738 
739 	if (rc)
740 		goto err_sk_put;
741 
742 	return 0;
743 
744 err_sk_put:
745 	sock_orphan(sk);
746 	sock_put(sk);
747 	return rc;
748 }
749 
750 static struct net_proto_family mctp_pf = {
751 	.family = PF_MCTP,
752 	.create = mctp_pf_create,
753 	.owner = THIS_MODULE,
754 };
755 
mctp_init(void)756 static __init int mctp_init(void)
757 {
758 	int rc;
759 
760 	/* ensure our uapi tag definitions match the header format */
761 	BUILD_BUG_ON(MCTP_TAG_OWNER != MCTP_HDR_FLAG_TO);
762 	BUILD_BUG_ON(MCTP_TAG_MASK != MCTP_HDR_TAG_MASK);
763 
764 	pr_info("mctp: management component transport protocol core\n");
765 
766 	rc = sock_register(&mctp_pf);
767 	if (rc)
768 		return rc;
769 
770 	rc = proto_register(&mctp_proto, 0);
771 	if (rc)
772 		goto err_unreg_sock;
773 
774 	rc = mctp_routes_init();
775 	if (rc)
776 		goto err_unreg_proto;
777 
778 	rc = mctp_neigh_init();
779 	if (rc)
780 		goto err_unreg_routes;
781 
782 	rc = mctp_device_init();
783 	if (rc)
784 		goto err_unreg_neigh;
785 
786 	return 0;
787 
788 err_unreg_neigh:
789 	mctp_neigh_exit();
790 err_unreg_routes:
791 	mctp_routes_exit();
792 err_unreg_proto:
793 	proto_unregister(&mctp_proto);
794 err_unreg_sock:
795 	sock_unregister(PF_MCTP);
796 
797 	return rc;
798 }
799 
mctp_exit(void)800 static __exit void mctp_exit(void)
801 {
802 	mctp_device_exit();
803 	mctp_neigh_exit();
804 	mctp_routes_exit();
805 	proto_unregister(&mctp_proto);
806 	sock_unregister(PF_MCTP);
807 }
808 
809 subsys_initcall(mctp_init);
810 module_exit(mctp_exit);
811 
812 MODULE_DESCRIPTION("MCTP core");
813 MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
814 
815 MODULE_ALIAS_NETPROTO(PF_MCTP);
816