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hc
2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/net/unix/af_unix.c
....@@ -1,12 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * NET4:	Implementation of BSD Unix domain sockets.
34  *
45  * Authors:	Alan Cox, <alan@lxorguk.ukuu.org.uk>
5
- *
6
- *		This program is free software; you can redistribute it and/or
7
- *		modify it under the terms of the GNU General Public License
8
- *		as published by the Free Software Foundation; either version
9
- *		2 of the License, or (at your option) any later version.
106  *
117  * Fixes:
128  *		Linus Torvalds	:	Assorted bug cures.
....@@ -48,7 +44,6 @@
4844  *	     Arnaldo C. Melo	:	Remove MOD_{INC,DEC}_USE_COUNT,
4945  *	     				the core infrastructure is doing that
5046  *	     				for all net proto families now (2.5.69+)
51
- *
5247  *
5348  * Known differences from reference BSD that was tested:
5449  *
....@@ -295,11 +290,9 @@
295290 
296291 		if (u->addr->len == len &&
297292 		    !memcmp(u->addr->name, sunname, len))
298
-			goto found;
293
+			return s;
299294 	}
300
-	s = NULL;
301
-found:
302
-	return s;
295
+	return NULL;
303296 }
304297 
305298 static inline struct sock *unix_find_socket_byname(struct net *net,
....@@ -445,7 +438,7 @@
445438 	 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
446439 	 * to other and its full, we will hang waiting for POLLOUT.
447440 	 */
448
-	if (unix_recvq_full(other) && !sock_flag(other, SOCK_DEAD))
441
+	if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD))
449442 		return 1;
450443 
451444 	if (connected)
....@@ -536,7 +529,7 @@
536529 	/* Clear state */
537530 	unix_state_lock(sk);
538531 	sock_orphan(sk);
539
-	sk->sk_shutdown = SHUTDOWN_MASK;
532
+	WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
540533 	path	     = u->path;
541534 	u->path.dentry = NULL;
542535 	u->path.mnt = NULL;
....@@ -554,7 +547,7 @@
554547 		if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
555548 			unix_state_lock(skpair);
556549 			/* No more writes */
557
-			skpair->sk_shutdown = SHUTDOWN_MASK;
550
+			WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
558551 			if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
559552 				skpair->sk_err = ECONNRESET;
560553 			unix_state_unlock(skpair);
....@@ -594,7 +587,7 @@
594587 	 *	  What the above comment does talk about? --ANK(980817)
595588 	 */
596589 
597
-	if (unix_tot_inflight)
590
+	if (READ_ONCE(unix_tot_inflight))
598591 		unix_gc();		/* Garbage collect fds */
599592 }
600593 
....@@ -643,7 +636,6 @@
643636 	int err;
644637 	struct sock *sk = sock->sk;
645638 	struct unix_sock *u = unix_sk(sk);
646
-	struct pid *old_pid = NULL;
647639 
648640 	err = -EOPNOTSUPP;
649641 	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
....@@ -664,7 +656,6 @@
664656 
665657 out_unlock:
666658 	unix_state_unlock(sk);
667
-	put_pid(old_pid);
668659 out:
669660 	return err;
670661 }
....@@ -706,12 +697,27 @@
706697 	if (mutex_lock_interruptible(&u->iolock))
707698 		return -EINTR;
708699 
709
-	sk->sk_peek_off = val;
700
+	WRITE_ONCE(sk->sk_peek_off, val);
710701 	mutex_unlock(&u->iolock);
711702 
712703 	return 0;
713704 }
714705 
706
+#ifdef CONFIG_PROC_FS
707
+static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
708
+{
709
+	struct sock *sk = sock->sk;
710
+	struct unix_sock *u;
711
+
712
+	if (sk) {
713
+		u = unix_sk(sock->sk);
714
+		seq_printf(m, "scm_fds: %u\n",
715
+			   atomic_read(&u->scm_stat.nr_fds));
716
+	}
717
+}
718
+#else
719
+#define unix_show_fdinfo NULL
720
+#endif
715721 
716722 static const struct proto_ops unix_stream_ops = {
717723 	.family =	PF_UNIX,
....@@ -729,14 +735,13 @@
729735 #endif
730736 	.listen =	unix_listen,
731737 	.shutdown =	unix_shutdown,
732
-	.setsockopt =	sock_no_setsockopt,
733
-	.getsockopt =	sock_no_getsockopt,
734738 	.sendmsg =	unix_stream_sendmsg,
735739 	.recvmsg =	unix_stream_recvmsg,
736740 	.mmap =		sock_no_mmap,
737741 	.sendpage =	unix_stream_sendpage,
738742 	.splice_read =	unix_stream_splice_read,
739743 	.set_peek_off =	unix_set_peek_off,
744
+	.show_fdinfo =	unix_show_fdinfo,
740745 };
741746 
742747 static const struct proto_ops unix_dgram_ops = {
....@@ -755,13 +760,12 @@
755760 #endif
756761 	.listen =	sock_no_listen,
757762 	.shutdown =	unix_shutdown,
758
-	.setsockopt =	sock_no_setsockopt,
759
-	.getsockopt =	sock_no_getsockopt,
760763 	.sendmsg =	unix_dgram_sendmsg,
761764 	.recvmsg =	unix_dgram_recvmsg,
762765 	.mmap =		sock_no_mmap,
763766 	.sendpage =	sock_no_sendpage,
764767 	.set_peek_off =	unix_set_peek_off,
768
+	.show_fdinfo =	unix_show_fdinfo,
765769 };
766770 
767771 static const struct proto_ops unix_seqpacket_ops = {
....@@ -780,13 +784,12 @@
780784 #endif
781785 	.listen =	unix_listen,
782786 	.shutdown =	unix_shutdown,
783
-	.setsockopt =	sock_no_setsockopt,
784
-	.getsockopt =	sock_no_getsockopt,
785787 	.sendmsg =	unix_seqpacket_sendmsg,
786788 	.recvmsg =	unix_seqpacket_recvmsg,
787789 	.mmap =		sock_no_mmap,
788790 	.sendpage =	sock_no_sendpage,
789791 	.set_peek_off =	unix_set_peek_off,
792
+	.show_fdinfo =	unix_show_fdinfo,
790793 };
791794 
792795 static struct proto unix_proto = {
....@@ -824,6 +827,7 @@
824827 	mutex_init(&u->bindlock); /* single task binding lock */
825828 	init_waitqueue_head(&u->peer_wait);
826829 	init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
830
+	memset(&u->scm_stat, 0, sizeof(struct scm_stat));
827831 	unix_insert_socket(unix_sockets_unbound(sk), sk);
828832 out:
829833 	if (sk == NULL)
....@@ -854,7 +858,7 @@
854858 		 */
855859 	case SOCK_RAW:
856860 		sock->type = SOCK_DGRAM;
857
-		/* fall through */
861
+		fallthrough;
858862 	case SOCK_DGRAM:
859863 		sock->ops = &unix_dgram_ops;
860864 		break;
....@@ -895,7 +899,6 @@
895899 	if (err)
896900 		return err;
897901 
898
-	err = 0;
899902 	if (u->addr)
900903 		goto out;
901904 
....@@ -1223,6 +1226,7 @@
12231226 }
12241227 
12251228 static long unix_wait_for_peer(struct sock *other, long timeo)
1229
+	__releases(&unix_sk(other)->lock)
12261230 {
12271231 	struct unix_sock *u = unix_sk(other);
12281232 	int sched;
....@@ -1232,7 +1236,7 @@
12321236 
12331237 	sched = !sock_flag(other, SOCK_DEAD) &&
12341238 		!(other->sk_shutdown & RCV_SHUTDOWN) &&
1235
-		unix_recvq_full(other);
1239
+		unix_recvq_full_lockless(other);
12361240 
12371241 	unix_state_unlock(other);
12381242 
....@@ -1655,6 +1659,24 @@
16551659 	       unix_secdata_eq(scm, skb);
16561660 }
16571661 
1662
+static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1663
+{
1664
+	struct scm_fp_list *fp = UNIXCB(skb).fp;
1665
+	struct unix_sock *u = unix_sk(sk);
1666
+
1667
+	if (unlikely(fp && fp->count))
1668
+		atomic_add(fp->count, &u->scm_stat.nr_fds);
1669
+}
1670
+
1671
+static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1672
+{
1673
+	struct scm_fp_list *fp = UNIXCB(skb).fp;
1674
+	struct unix_sock *u = unix_sk(sk);
1675
+
1676
+	if (unlikely(fp && fp->count))
1677
+		atomic_sub(fp->count, &u->scm_stat.nr_fds);
1678
+}
1679
+
16581680 /*
16591681  *	Send AF_UNIX data.
16601682  */
....@@ -1841,6 +1863,7 @@
18411863 	if (sock_flag(other, SOCK_RCVTSTAMP))
18421864 		__net_timestamp(skb);
18431865 	maybe_add_creds(skb, sock, other);
1866
+	scm_stat_add(other, skb);
18441867 	skb_queue_tail(&other->sk_receive_queue, skb);
18451868 	unix_state_unlock(other);
18461869 	other->sk_data_ready(other);
....@@ -1943,6 +1966,7 @@
19431966 			goto pipe_err_free;
19441967 
19451968 		maybe_add_creds(skb, sock, other);
1969
+		scm_stat_add(other, skb);
19461970 		skb_queue_tail(&other->sk_receive_queue, skb);
19471971 		unix_state_unlock(other);
19481972 		other->sk_data_ready(other);
....@@ -1984,6 +2008,7 @@
19842008 
19852009 	if (false) {
19862010 alloc_skb:
2011
+		spin_unlock(&other->sk_receive_queue.lock);
19872012 		unix_state_unlock(other);
19882013 		mutex_unlock(&unix_sk(other)->iolock);
19892014 		newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
....@@ -2023,6 +2048,7 @@
20232048 		init_scm = false;
20242049 	}
20252050 
2051
+	spin_lock(&other->sk_receive_queue.lock);
20262052 	skb = skb_peek_tail(&other->sk_receive_queue);
20272053 	if (tail && tail == skb) {
20282054 		skb = newskb;
....@@ -2053,14 +2079,11 @@
20532079 	refcount_add(size, &sk->sk_wmem_alloc);
20542080 
20552081 	if (newskb) {
2056
-		err = unix_scm_to_skb(&scm, skb, false);
2057
-		if (err)
2058
-			goto err_state_unlock;
2059
-		spin_lock(&other->sk_receive_queue.lock);
2082
+		unix_scm_to_skb(&scm, skb, false);
20602083 		__skb_queue_tail(&other->sk_receive_queue, newskb);
2061
-		spin_unlock(&other->sk_receive_queue.lock);
20622084 	}
20632085 
2086
+	spin_unlock(&other->sk_receive_queue.lock);
20642087 	unix_state_unlock(other);
20652088 	mutex_unlock(&unix_sk(other)->iolock);
20662089 
....@@ -2129,8 +2152,8 @@
21292152 	struct unix_sock *u = unix_sk(sk);
21302153 	struct sk_buff *skb, *last;
21312154 	long timeo;
2155
+	int skip;
21322156 	int err;
2133
-	int peeked, skip;
21342157 
21352158 	err = -EOPNOTSUPP;
21362159 	if (flags&MSG_OOB)
....@@ -2142,17 +2165,21 @@
21422165 		mutex_lock(&u->iolock);
21432166 
21442167 		skip = sk_peek_offset(sk, flags);
2145
-		skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
2146
-					      &err, &last);
2147
-		if (skb)
2168
+		skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2169
+					      &skip, &err, &last);
2170
+		if (skb) {
2171
+			if (!(flags & MSG_PEEK))
2172
+				scm_stat_del(sk, skb);
21482173 			break;
2174
+		}
21492175 
21502176 		mutex_unlock(&u->iolock);
21512177 
21522178 		if (err != -EAGAIN)
21532179 			break;
21542180 	} while (timeo &&
2155
-		 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2181
+		 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2182
+					      &err, &timeo, last));
21562183 
21572184 	if (!skb) { /* implies iolock unlocked */
21582185 		unix_state_lock(sk);
....@@ -2437,8 +2464,10 @@
24372464 
24382465 			sk_peek_offset_bwd(sk, chunk);
24392466 
2440
-			if (UNIXCB(skb).fp)
2467
+			if (UNIXCB(skb).fp) {
2468
+				scm_stat_del(sk, skb);
24412469 				unix_detach_fds(&scm, skb);
2470
+			}
24422471 
24432472 			if (unix_skb_len(skb))
24442473 				break;
....@@ -2551,7 +2580,7 @@
25512580 	++mode;
25522581 
25532582 	unix_state_lock(sk);
2554
-	sk->sk_shutdown |= mode;
2583
+	WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | mode);
25552584 	other = unix_peer(sk);
25562585 	if (other)
25572586 		sock_hold(other);
....@@ -2568,7 +2597,7 @@
25682597 		if (mode&SEND_SHUTDOWN)
25692598 			peer_mode |= RCV_SHUTDOWN;
25702599 		unix_state_lock(other);
2571
-		other->sk_shutdown |= peer_mode;
2600
+		WRITE_ONCE(other->sk_shutdown, other->sk_shutdown | peer_mode);
25722601 		unix_state_unlock(other);
25732602 		other->sk_state_change(other);
25742603 		if (peer_mode == SHUTDOWN_MASK)
....@@ -2687,16 +2716,18 @@
26872716 {
26882717 	struct sock *sk = sock->sk;
26892718 	__poll_t mask;
2719
+	u8 shutdown;
26902720 
26912721 	sock_poll_wait(file, sock, wait);
26922722 	mask = 0;
2723
+	shutdown = READ_ONCE(sk->sk_shutdown);
26932724 
26942725 	/* exceptional events? */
26952726 	if (sk->sk_err)
26962727 		mask |= EPOLLERR;
2697
-	if (sk->sk_shutdown == SHUTDOWN_MASK)
2728
+	if (shutdown == SHUTDOWN_MASK)
26982729 		mask |= EPOLLHUP;
2699
-	if (sk->sk_shutdown & RCV_SHUTDOWN)
2730
+	if (shutdown & RCV_SHUTDOWN)
27002731 		mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
27012732 
27022733 	/* readable? */
....@@ -2724,18 +2755,20 @@
27242755 	struct sock *sk = sock->sk, *other;
27252756 	unsigned int writable;
27262757 	__poll_t mask;
2758
+	u8 shutdown;
27272759 
27282760 	sock_poll_wait(file, sock, wait);
27292761 	mask = 0;
2762
+	shutdown = READ_ONCE(sk->sk_shutdown);
27302763 
27312764 	/* exceptional events? */
27322765 	if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
27332766 		mask |= EPOLLERR |
27342767 			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
27352768 
2736
-	if (sk->sk_shutdown & RCV_SHUTDOWN)
2769
+	if (shutdown & RCV_SHUTDOWN)
27372770 		mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2738
-	if (sk->sk_shutdown == SHUTDOWN_MASK)
2771
+	if (shutdown == SHUTDOWN_MASK)
27392772 		mask |= EPOLLHUP;
27402773 
27412774 	/* readable? */
....@@ -2949,7 +2982,7 @@
29492982 {
29502983 	int rc = -1;
29512984 
2952
-	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2985
+	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
29532986 
29542987 	rc = proto_register(&unix_proto, 1);
29552988 	if (rc != 0) {
....@@ -2978,4 +3011,5 @@
29783011 module_exit(af_unix_exit);
29793012 
29803013 MODULE_LICENSE("GPL");
3014
+MODULE_IMPORT_NS(VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver);
29813015 MODULE_ALIAS_NETPROTO(PF_UNIX);