From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 11 Apr 2024 10:27:49 +0200
Subject: Adding upstream version 6.6.15.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 net/ax25/ax25_uid.c | 204 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 204 insertions(+)
 create mode 100644 net/ax25/ax25_uid.c

(limited to 'net/ax25/ax25_uid.c')

diff --git a/net/ax25/ax25_uid.c b/net/ax25/ax25_uid.c
new file mode 100644
index 0000000000..241e4680ec
--- /dev/null
+++ b/net/ax25/ax25_uid.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/notifier.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/sysctl.h>
+#include <linux/export.h>
+#include <net/ip.h>
+#include <net/arp.h>
+
+/*
+ *	Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
+ */
+
+static HLIST_HEAD(ax25_uid_list);
+static DEFINE_RWLOCK(ax25_uid_lock);
+
+int ax25_uid_policy;
+
+EXPORT_SYMBOL(ax25_uid_policy);
+
+ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
+{
+	ax25_uid_assoc *ax25_uid, *res = NULL;
+
+	read_lock(&ax25_uid_lock);
+	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+		if (uid_eq(ax25_uid->uid, uid)) {
+			ax25_uid_hold(ax25_uid);
+			res = ax25_uid;
+			break;
+		}
+	}
+	read_unlock(&ax25_uid_lock);
+
+	return res;
+}
+
+EXPORT_SYMBOL(ax25_findbyuid);
+
+int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
+{
+	ax25_uid_assoc *ax25_uid;
+	ax25_uid_assoc *user;
+	unsigned long res;
+
+	switch (cmd) {
+	case SIOCAX25GETUID:
+		res = -ENOENT;
+		read_lock(&ax25_uid_lock);
+		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
+				res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
+				break;
+			}
+		}
+		read_unlock(&ax25_uid_lock);
+
+		return res;
+
+	case SIOCAX25ADDUID:
+	{
+		kuid_t sax25_kuid;
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
+		if (!uid_valid(sax25_kuid))
+			return -EINVAL;
+		user = ax25_findbyuid(sax25_kuid);
+		if (user) {
+			ax25_uid_put(user);
+			return -EEXIST;
+		}
+		if (sax->sax25_uid == 0)
+			return -EINVAL;
+		if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
+			return -ENOMEM;
+
+		refcount_set(&ax25_uid->refcount, 1);
+		ax25_uid->uid  = sax25_kuid;
+		ax25_uid->call = sax->sax25_call;
+
+		write_lock(&ax25_uid_lock);
+		hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
+		write_unlock(&ax25_uid_lock);
+
+		return 0;
+	}
+	case SIOCAX25DELUID:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		ax25_uid = NULL;
+		write_lock(&ax25_uid_lock);
+		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
+				break;
+		}
+		if (ax25_uid == NULL) {
+			write_unlock(&ax25_uid_lock);
+			return -ENOENT;
+		}
+		hlist_del_init(&ax25_uid->uid_node);
+		ax25_uid_put(ax25_uid);
+		write_unlock(&ax25_uid_lock);
+
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;	/*NOTREACHED */
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(ax25_uid_lock)
+{
+	read_lock(&ax25_uid_lock);
+	return seq_hlist_start_head(&ax25_uid_list, *pos);
+}
+
+static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	return seq_hlist_next(v, &ax25_uid_list, pos);
+}
+
+static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
+	__releases(ax25_uid_lock)
+{
+	read_unlock(&ax25_uid_lock);
+}
+
+static int ax25_uid_seq_show(struct seq_file *seq, void *v)
+{
+	char buf[11];
+
+	if (v == SEQ_START_TOKEN)
+		seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
+	else {
+		struct ax25_uid_assoc *pt;
+
+		pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
+		seq_printf(seq, "%6d %s\n",
+			from_kuid_munged(seq_user_ns(seq), pt->uid),
+			ax2asc(buf, &pt->call));
+	}
+	return 0;
+}
+
+const struct seq_operations ax25_uid_seqops = {
+	.start = ax25_uid_seq_start,
+	.next = ax25_uid_seq_next,
+	.stop = ax25_uid_seq_stop,
+	.show = ax25_uid_seq_show,
+};
+#endif
+
+/*
+ *	Free all memory associated with UID/Callsign structures.
+ */
+void __exit ax25_uid_free(void)
+{
+	ax25_uid_assoc *ax25_uid;
+
+	write_lock(&ax25_uid_lock);
+again:
+	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+		hlist_del_init(&ax25_uid->uid_node);
+		ax25_uid_put(ax25_uid);
+		goto again;
+	}
+	write_unlock(&ax25_uid_lock);
+}
-- 
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