1 files changed, 348 insertions, 0 deletions

diff --git a/net/unix/diag.c b/net/unix/diag.c
new file mode 100644
index 000000000..951b33fa8
--- /dev/null
+++ b/net/unix/diag.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/sock_diag.h>
+#include <linux/unix_diag.h>
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <linux/uidgid.h>
+#include <net/netlink.h>
+#include <net/af_unix.h>
+#include <net/tcp_states.h>
+#include <net/sock.h>
+
+static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
+{
+	/* might or might not have unix_table_lock */
+	struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
+
+	if (!addr)
+		return 0;
+
+	return nla_put(nlskb, UNIX_DIAG_NAME, addr->len - sizeof(short),
+		       addr->name->sun_path);
+}
+
+static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
+{
+	struct dentry *dentry = unix_sk(sk)->path.dentry;
+
+	if (dentry) {
+		struct unix_diag_vfs uv = {
+			.udiag_vfs_ino = d_backing_inode(dentry)->i_ino,
+			.udiag_vfs_dev = dentry->d_sb->s_dev,
+		};
+
+		return nla_put(nlskb, UNIX_DIAG_VFS, sizeof(uv), &uv);
+	}
+
+	return 0;
+}
+
+static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
+{
+	struct sock *peer;
+	int ino;
+
+	peer = unix_peer_get(sk);
+	if (peer) {
+		unix_state_lock(peer);
+		ino = sock_i_ino(peer);
+		unix_state_unlock(peer);
+		sock_put(peer);
+
+		return nla_put_u32(nlskb, UNIX_DIAG_PEER, ino);
+	}
+
+	return 0;
+}
+
+static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
+{
+	struct sk_buff *skb;
+	struct nlattr *attr;
+	u32 *buf;
+	int i;
+
+	if (sk->sk_state == TCP_LISTEN) {
+		spin_lock(&sk->sk_receive_queue.lock);
+
+		attr = nla_reserve(nlskb, UNIX_DIAG_ICONS,
+				   sk->sk_receive_queue.qlen * sizeof(u32));
+		if (!attr)
+			goto errout;
+
+		buf = nla_data(attr);
+		i = 0;
+		skb_queue_walk(&sk->sk_receive_queue, skb) {
+			struct sock *req, *peer;
+
+			req = skb->sk;
+			/*
+			 * The state lock is outer for the same sk's
+			 * queue lock. With the other's queue locked it's
+			 * OK to lock the state.
+			 */
+			unix_state_lock_nested(req);
+			peer = unix_sk(req)->peer;
+			buf[i++] = (peer ? sock_i_ino(peer) : 0);
+			unix_state_unlock(req);
+		}
+		spin_unlock(&sk->sk_receive_queue.lock);
+	}
+
+	return 0;
+
+errout:
+	spin_unlock(&sk->sk_receive_queue.lock);
+	return -EMSGSIZE;
+}
+
+static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
+{
+	struct unix_diag_rqlen rql;
+
+	if (sk->sk_state == TCP_LISTEN) {
+		rql.udiag_rqueue = sk->sk_receive_queue.qlen;
+		rql.udiag_wqueue = sk->sk_max_ack_backlog;
+	} else {
+		rql.udiag_rqueue = (u32) unix_inq_len(sk);
+		rql.udiag_wqueue = (u32) unix_outq_len(sk);
+	}
+
+	return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql);
+}
+
+static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb,
+			    struct user_namespace *user_ns)
+{
+	uid_t uid = from_kuid_munged(user_ns, sock_i_uid(sk));
+	return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &uid);
+}
+
+static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
+			struct user_namespace *user_ns,
+			u32 portid, u32 seq, u32 flags, int sk_ino)
+{
+	struct nlmsghdr *nlh;
+	struct unix_diag_msg *rep;
+
+	nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
+			flags);
+	if (!nlh)
+		return -EMSGSIZE;
+
+	rep = nlmsg_data(nlh);
+	rep->udiag_family = AF_UNIX;
+	rep->udiag_type = sk->sk_type;
+	rep->udiag_state = sk->sk_state;
+	rep->pad = 0;
+	rep->udiag_ino = sk_ino;
+	sock_diag_save_cookie(sk, rep->udiag_cookie);
+
+	if ((req->udiag_show & UDIAG_SHOW_NAME) &&
+	    sk_diag_dump_name(sk, skb))
+		goto out_nlmsg_trim;
+
+	if ((req->udiag_show & UDIAG_SHOW_VFS) &&
+	    sk_diag_dump_vfs(sk, skb))
+		goto out_nlmsg_trim;
+
+	if ((req->udiag_show & UDIAG_SHOW_PEER) &&
+	    sk_diag_dump_peer(sk, skb))
+		goto out_nlmsg_trim;
+
+	if ((req->udiag_show & UDIAG_SHOW_ICONS) &&
+	    sk_diag_dump_icons(sk, skb))
+		goto out_nlmsg_trim;
+
+	if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
+	    sk_diag_show_rqlen(sk, skb))
+		goto out_nlmsg_trim;
+
+	if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
+	    sock_diag_put_meminfo(sk, skb, UNIX_DIAG_MEMINFO))
+		goto out_nlmsg_trim;
+
+	if (nla_put_u8(skb, UNIX_DIAG_SHUTDOWN, sk->sk_shutdown))
+		goto out_nlmsg_trim;
+
+	if ((req->udiag_show & UDIAG_SHOW_UID) &&
+	    sk_diag_dump_uid(sk, skb, user_ns))
+		goto out_nlmsg_trim;
+
+	nlmsg_end(skb, nlh);
+	return 0;
+
+out_nlmsg_trim:
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
+}
+
+static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
+			struct user_namespace *user_ns,
+			u32 portid, u32 seq, u32 flags)
+{
+	int sk_ino;
+
+	unix_state_lock(sk);
+	sk_ino = sock_i_ino(sk);
+	unix_state_unlock(sk);
+
+	if (!sk_ino)
+		return 0;
+
+	return sk_diag_fill(sk, skb, req, user_ns, portid, seq, flags, sk_ino);
+}
+
+static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct unix_diag_req *req;
+	int num, s_num, slot, s_slot;
+	struct net *net = sock_net(skb->sk);
+
+	req = nlmsg_data(cb->nlh);
+
+	s_slot = cb->args[0];
+	num = s_num = cb->args[1];
+
+	spin_lock(&unix_table_lock);
+	for (slot = s_slot;
+	     slot < ARRAY_SIZE(unix_socket_table);
+	     s_num = 0, slot++) {
+		struct sock *sk;
+
+		num = 0;
+		sk_for_each(sk, &unix_socket_table[slot]) {
+			if (!net_eq(sock_net(sk), net))
+				continue;
+			if (num < s_num)
+				goto next;
+			if (!(req->udiag_states & (1 << sk->sk_state)))
+				goto next;
+			if (sk_diag_dump(sk, skb, req, sk_user_ns(skb->sk),
+					 NETLINK_CB(cb->skb).portid,
+					 cb->nlh->nlmsg_seq,
+					 NLM_F_MULTI) < 0)
+				goto done;
+next:
+			num++;
+		}
+	}
+done:
+	spin_unlock(&unix_table_lock);
+	cb->args[0] = slot;
+	cb->args[1] = num;
+
+	return skb->len;
+}
+
+static struct sock *unix_lookup_by_ino(unsigned int ino)
+{
+	int i;
+	struct sock *sk;
+
+	spin_lock(&unix_table_lock);
+	for (i = 0; i < ARRAY_SIZE(unix_socket_table); i++) {
+		sk_for_each(sk, &unix_socket_table[i])
+			if (ino == sock_i_ino(sk)) {
+				sock_hold(sk);
+				spin_unlock(&unix_table_lock);
+
+				return sk;
+			}
+	}
+
+	spin_unlock(&unix_table_lock);
+	return NULL;
+}
+
+static int unix_diag_get_exact(struct sk_buff *in_skb,
+			       const struct nlmsghdr *nlh,
+			       struct unix_diag_req *req)
+{
+	int err = -EINVAL;
+	struct sock *sk;
+	struct sk_buff *rep;
+	unsigned int extra_len;
+	struct net *net = sock_net(in_skb->sk);
+
+	if (req->udiag_ino == 0)
+		goto out_nosk;
+
+	sk = unix_lookup_by_ino(req->udiag_ino);
+	err = -ENOENT;
+	if (sk == NULL)
+		goto out_nosk;
+	if (!net_eq(sock_net(sk), net))
+		goto out;
+
+	err = sock_diag_check_cookie(sk, req->udiag_cookie);
+	if (err)
+		goto out;
+
+	extra_len = 256;
+again:
+	err = -ENOMEM;
+	rep = nlmsg_new(sizeof(struct unix_diag_msg) + extra_len, GFP_KERNEL);
+	if (!rep)
+		goto out;
+
+	err = sk_diag_fill(sk, rep, req, sk_user_ns(NETLINK_CB(in_skb).sk),
+			   NETLINK_CB(in_skb).portid,
+			   nlh->nlmsg_seq, 0, req->udiag_ino);
+	if (err < 0) {
+		nlmsg_free(rep);
+		extra_len += 256;
+		if (extra_len >= PAGE_SIZE)
+			goto out;
+
+		goto again;
+	}
+	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
+			      MSG_DONTWAIT);
+	if (err > 0)
+		err = 0;
+out:
+	if (sk)
+		sock_put(sk);
+out_nosk:
+	return err;
+}
+
+static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
+{
+	int hdrlen = sizeof(struct unix_diag_req);
+	struct net *net = sock_net(skb->sk);
+
+	if (nlmsg_len(h) < hdrlen)
+		return -EINVAL;
+
+	if (h->nlmsg_flags & NLM_F_DUMP) {
+		struct netlink_dump_control c = {
+			.dump = unix_diag_dump,
+		};
+		return netlink_dump_start(net->diag_nlsk, skb, h, &c);
+	} else
+		return unix_diag_get_exact(skb, h, nlmsg_data(h));
+}
+
+static const struct sock_diag_handler unix_diag_handler = {
+	.family = AF_UNIX,
+	.dump = unix_diag_handler_dump,
+};
+
+static int __init unix_diag_init(void)
+{
+	return sock_diag_register(&unix_diag_handler);
+}
+
+static void __exit unix_diag_exit(void)
+{
+	sock_diag_unregister(&unix_diag_handler);
+}
+
+module_init(unix_diag_init);
+module_exit(unix_diag_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);