1 files changed, 191 insertions, 0 deletions

diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
new file mode 100644
index 00000000..69ff52c0
--- /dev/null
+++ b/security/keys/user_defined.c
@@ -0,0 +1,191 @@
+/* user_defined.c: user defined key type
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <keys/user-type.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/*
+ * user defined keys take an arbitrary string as the description and an
+ * arbitrary blob of data as the payload
+ */
+struct key_type key_type_user = {
+	.name		= "user",
+	.instantiate	= user_instantiate,
+	.update		= user_update,
+	.match		= user_match,
+	.revoke		= user_revoke,
+	.destroy	= user_destroy,
+	.describe	= user_describe,
+	.read		= user_read,
+};
+
+EXPORT_SYMBOL_GPL(key_type_user);
+
+/*
+ * instantiate a user defined key
+ */
+int user_instantiate(struct key *key, const void *data, size_t datalen)
+{
+	struct user_key_payload *upayload;
+	int ret;
+
+	ret = -EINVAL;
+	if (datalen <= 0 || datalen > 32767 || !data)
+		goto error;
+
+	ret = key_payload_reserve(key, datalen);
+	if (ret < 0)
+		goto error;
+
+	ret = -ENOMEM;
+	upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+	if (!upayload)
+		goto error;
+
+	/* attach the data */
+	upayload->datalen = datalen;
+	memcpy(upayload->data, data, datalen);
+	rcu_assign_pointer(key->payload.data, upayload);
+	ret = 0;
+
+error:
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(user_instantiate);
+
+/*
+ * update a user defined key
+ * - the key's semaphore is write-locked
+ */
+int user_update(struct key *key, const void *data, size_t datalen)
+{
+	struct user_key_payload *upayload, *zap;
+	int ret;
+
+	ret = -EINVAL;
+	if (datalen <= 0 || datalen > 32767 || !data)
+		goto error;
+
+	/* construct a replacement payload */
+	ret = -ENOMEM;
+	upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+	if (!upayload)
+		goto error;
+
+	upayload->datalen = datalen;
+	memcpy(upayload->data, data, datalen);
+
+	/* check the quota and attach the new data */
+	zap = upayload;
+
+	ret = key_payload_reserve(key, datalen);
+
+	if (ret == 0) {
+		/* attach the new data, displacing the old */
+		zap = key->payload.data;
+		rcu_assign_pointer(key->payload.data, upayload);
+		key->expiry = 0;
+	}
+
+	if (zap)
+		kfree_rcu(zap, rcu);
+
+error:
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(user_update);
+
+/*
+ * match users on their name
+ */
+int user_match(const struct key *key, const void *description)
+{
+	return strcmp(key->description, description) == 0;
+}
+
+EXPORT_SYMBOL_GPL(user_match);
+
+/*
+ * dispose of the links from a revoked keyring
+ * - called with the key sem write-locked
+ */
+void user_revoke(struct key *key)
+{
+	struct user_key_payload *upayload = key->payload.data;
+
+	/* clear the quota */
+	key_payload_reserve(key, 0);
+
+	if (upayload) {
+		rcu_assign_pointer(key->payload.data, NULL);
+		kfree_rcu(upayload, rcu);
+	}
+}
+
+EXPORT_SYMBOL(user_revoke);
+
+/*
+ * dispose of the data dangling from the corpse of a user key
+ */
+void user_destroy(struct key *key)
+{
+	struct user_key_payload *upayload = key->payload.data;
+
+	kfree(upayload);
+}
+
+EXPORT_SYMBOL_GPL(user_destroy);
+
+/*
+ * describe the user key
+ */
+void user_describe(const struct key *key, struct seq_file *m)
+{
+	seq_puts(m, key->description);
+	if (key_is_instantiated(key))
+		seq_printf(m, ": %u", key->datalen);
+}
+
+EXPORT_SYMBOL_GPL(user_describe);
+
+/*
+ * read the key data
+ * - the key's semaphore is read-locked
+ */
+long user_read(const struct key *key, char __user *buffer, size_t buflen)
+{
+	struct user_key_payload *upayload;
+	long ret;
+
+	upayload = rcu_dereference_key(key);
+	ret = upayload->datalen;
+
+	/* we can return the data as is */
+	if (buffer && buflen > 0) {
+		if (buflen > upayload->datalen)
+			buflen = upayload->datalen;
+
+		if (copy_to_user(buffer, upayload->data, buflen) != 0)
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(user_read);