1 files changed, 323 insertions, 0 deletions
diff --git a/security/keys/proc.c b/security/keys/proc.c
new file mode 100644
index 000000000..4f4e2c182
--- /dev/null
+++ b/security/keys/proc.c
@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* procfs files for key database enumeration
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <asm/errno.h>
+#include "internal.h"
+
+static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
+static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
+static void proc_keys_stop(struct seq_file *p, void *v);
+static int proc_keys_show(struct seq_file *m, void *v);
+
+static const struct seq_operations proc_keys_ops = {
+	.start	= proc_keys_start,
+	.next	= proc_keys_next,
+	.stop	= proc_keys_stop,
+	.show	= proc_keys_show,
+};
+
+static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
+static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
+static void proc_key_users_stop(struct seq_file *p, void *v);
+static int proc_key_users_show(struct seq_file *m, void *v);
+
+static const struct seq_operations proc_key_users_ops = {
+	.start	= proc_key_users_start,
+	.next	= proc_key_users_next,
+	.stop	= proc_key_users_stop,
+	.show	= proc_key_users_show,
+};
+
+/*
+ * Declare the /proc files.
+ */
+static int __init key_proc_init(void)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_seq("keys", 0, NULL, &proc_keys_ops);
+	if (!p)
+		panic("Cannot create /proc/keys\n");
+
+	p = proc_create_seq("key-users", 0, NULL, &proc_key_users_ops);
+	if (!p)
+		panic("Cannot create /proc/key-users\n");
+
+	return 0;
+}
+
+__initcall(key_proc_init);
+
+/*
+ * Implement "/proc/keys" to provide a list of the keys on the system that
+ * grant View permission to the caller.
+ */
+static struct rb_node *key_serial_next(struct seq_file *p, struct rb_node *n)
+{
+	struct user_namespace *user_ns = seq_user_ns(p);
+
+	n = rb_next(n);
+	while (n) {
+		struct key *key = rb_entry(n, struct key, serial_node);
+		if (kuid_has_mapping(user_ns, key->user->uid))
+			break;
+		n = rb_next(n);
+	}
+	return n;
+}
+
+static struct key *find_ge_key(struct seq_file *p, key_serial_t id)
+{
+	struct user_namespace *user_ns = seq_user_ns(p);
+	struct rb_node *n = key_serial_tree.rb_node;
+	struct key *minkey = NULL;
+
+	while (n) {
+		struct key *key = rb_entry(n, struct key, serial_node);
+		if (id < key->serial) {
+			if (!minkey || minkey->serial > key->serial)
+				minkey = key;
+			n = n->rb_left;
+		} else if (id > key->serial) {
+			n = n->rb_right;
+		} else {
+			minkey = key;
+			break;
+		}
+		key = NULL;
+	}
+
+	if (!minkey)
+		return NULL;
+
+	for (;;) {
+		if (kuid_has_mapping(user_ns, minkey->user->uid))
+			return minkey;
+		n = rb_next(&minkey->serial_node);
+		if (!n)
+			return NULL;
+		minkey = rb_entry(n, struct key, serial_node);
+	}
+}
+
+static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
+	__acquires(key_serial_lock)
+{
+	key_serial_t pos = *_pos;
+	struct key *key;
+
+	spin_lock(&key_serial_lock);
+
+	if (*_pos > INT_MAX)
+		return NULL;
+	key = find_ge_key(p, pos);
+	if (!key)
+		return NULL;
+	*_pos = key->serial;
+	return &key->serial_node;
+}
+
+static inline key_serial_t key_node_serial(struct rb_node *n)
+{
+	struct key *key = rb_entry(n, struct key, serial_node);
+	return key->serial;
+}
+
+static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
+{
+	struct rb_node *n;
+
+	n = key_serial_next(p, v);
+	if (n)
+		*_pos = key_node_serial(n);
+	else
+		(*_pos)++;
+	return n;
+}
+
+static void proc_keys_stop(struct seq_file *p, void *v)
+	__releases(key_serial_lock)
+{
+	spin_unlock(&key_serial_lock);
+}
+
+static int proc_keys_show(struct seq_file *m, void *v)
+{
+	struct rb_node *_p = v;
+	struct key *key = rb_entry(_p, struct key, serial_node);
+	unsigned long flags;
+	key_ref_t key_ref, skey_ref;
+	time64_t now, expiry;
+	char xbuf[16];
+	short state;
+	u64 timo;
+	int rc;
+
+	struct keyring_search_context ctx = {
+		.index_key		= key->index_key,
+		.cred			= m->file->f_cred,
+		.match_data.cmp		= lookup_user_key_possessed,
+		.match_data.raw_data	= key,
+		.match_data.lookup_type	= KEYRING_SEARCH_LOOKUP_DIRECT,
+		.flags			= (KEYRING_SEARCH_NO_STATE_CHECK |
+					   KEYRING_SEARCH_RECURSE),
+	};
+
+	key_ref = make_key_ref(key, 0);
+
+	/* determine if the key is possessed by this process (a test we can
+	 * skip if the key does not indicate the possessor can view it
+	 */
+	if (key->perm & KEY_POS_VIEW) {
+		rcu_read_lock();
+		skey_ref = search_cred_keyrings_rcu(&ctx);
+		rcu_read_unlock();
+		if (!IS_ERR(skey_ref)) {
+			key_ref_put(skey_ref);
+			key_ref = make_key_ref(key, 1);
+		}
+	}
+
+	/* check whether the current task is allowed to view the key */
+	rc = key_task_permission(key_ref, ctx.cred, KEY_NEED_VIEW);
+	if (rc < 0)
+		return 0;
+
+	now = ktime_get_real_seconds();
+
+	rcu_read_lock();
+
+	/* come up with a suitable timeout value */
+	expiry = READ_ONCE(key->expiry);
+	if (expiry == TIME64_MAX) {
+		memcpy(xbuf, "perm", 5);
+	} else if (now >= expiry) {
+		memcpy(xbuf, "expd", 5);
+	} else {
+		timo = expiry - now;
+
+		if (timo < 60)
+			sprintf(xbuf, "%llus", timo);
+		else if (timo < 60*60)
+			sprintf(xbuf, "%llum", div_u64(timo, 60));
+		else if (timo < 60*60*24)
+			sprintf(xbuf, "%lluh", div_u64(timo, 60 * 60));
+		else if (timo < 60*60*24*7)
+			sprintf(xbuf, "%llud", div_u64(timo, 60 * 60 * 24));
+		else
+			sprintf(xbuf, "%lluw", div_u64(timo, 60 * 60 * 24 * 7));
+	}
+
+	state = key_read_state(key);
+
+#define showflag(FLAGS, LETTER, FLAG) \
+	((FLAGS & (1 << FLAG)) ? LETTER : '-')
+
+	flags = READ_ONCE(key->flags);
+	seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
+		   key->serial,
+		   state != KEY_IS_UNINSTANTIATED ? 'I' : '-',
+		   showflag(flags, 'R', KEY_FLAG_REVOKED),
+		   showflag(flags, 'D', KEY_FLAG_DEAD),
+		   showflag(flags, 'Q', KEY_FLAG_IN_QUOTA),
+		   showflag(flags, 'U', KEY_FLAG_USER_CONSTRUCT),
+		   state < 0 ? 'N' : '-',
+		   showflag(flags, 'i', KEY_FLAG_INVALIDATED),
+		   refcount_read(&key->usage),
+		   xbuf,
+		   key->perm,
+		   from_kuid_munged(seq_user_ns(m), key->uid),
+		   from_kgid_munged(seq_user_ns(m), key->gid),
+		   key->type->name);
+
+#undef showflag
+
+	if (key->type->describe)
+		key->type->describe(key, m);
+	seq_putc(m, '\n');
+
+	rcu_read_unlock();
+	return 0;
+}
+
+static struct rb_node *__key_user_next(struct user_namespace *user_ns, struct rb_node *n)
+{
+	while (n) {
+		struct key_user *user = rb_entry(n, struct key_user, node);
+		if (kuid_has_mapping(user_ns, user->uid))
+			break;
+		n = rb_next(n);
+	}
+	return n;
+}
+
+static struct rb_node *key_user_next(struct user_namespace *user_ns, struct rb_node *n)
+{
+	return __key_user_next(user_ns, rb_next(n));
+}
+
+static struct rb_node *key_user_first(struct user_namespace *user_ns, struct rb_root *r)
+{
+	struct rb_node *n = rb_first(r);
+	return __key_user_next(user_ns, n);
+}
+
+static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
+	__acquires(key_user_lock)
+{
+	struct rb_node *_p;
+	loff_t pos = *_pos;
+
+	spin_lock(&key_user_lock);
+
+	_p = key_user_first(seq_user_ns(p), &key_user_tree);
+	while (pos > 0 && _p) {
+		pos--;
+		_p = key_user_next(seq_user_ns(p), _p);
+	}
+
+	return _p;
+}
+
+static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
+{
+	(*_pos)++;
+	return key_user_next(seq_user_ns(p), (struct rb_node *)v);
+}
+
+static void proc_key_users_stop(struct seq_file *p, void *v)
+	__releases(key_user_lock)
+{
+	spin_unlock(&key_user_lock);
+}
+
+static int proc_key_users_show(struct seq_file *m, void *v)
+{
+	struct rb_node *_p = v;
+	struct key_user *user = rb_entry(_p, struct key_user, node);
+	unsigned maxkeys = uid_eq(user->uid, GLOBAL_ROOT_UID) ?
+		key_quota_root_maxkeys : key_quota_maxkeys;
+	unsigned maxbytes = uid_eq(user->uid, GLOBAL_ROOT_UID) ?
+		key_quota_root_maxbytes : key_quota_maxbytes;
+
+	seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
+		   from_kuid_munged(seq_user_ns(m), user->uid),
+		   refcount_read(&user->usage),
+		   atomic_read(&user->nkeys),
+		   atomic_read(&user->nikeys),
+		   user->qnkeys,
+		   maxkeys,
+		   user->qnbytes,
+		   maxbytes);
+
+	return 0;
+}