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-rw-r--r--security/keys/user_defined.c191
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 0000000..8d65b3a
--- /dev/null
+++ b/security/keys/user_defined.c
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+/* 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/sched.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+static int user_instantiate(struct key *key, const void *data, size_t datalen);
+static int user_duplicate(struct key *key, const struct key *source);
+static int user_update(struct key *key, const void *data, size_t datalen);
+static int user_match(const struct key *key, const void *criterion);
+static void user_destroy(struct key *key);
+static void user_describe(const struct key *user, struct seq_file *m);
+static long user_read(const struct key *key,
+ char __user *buffer, size_t buflen);
+
+/*
+ * 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,
+ .duplicate = user_duplicate,
+ .update = user_update,
+ .match = user_match,
+ .destroy = user_destroy,
+ .describe = user_describe,
+ .read = user_read,
+};
+
+/*****************************************************************************/
+/*
+ * instantiate a user defined key
+ */
+static int user_instantiate(struct key *key, const void *data, size_t datalen)
+{
+ int ret;
+
+ ret = -EINVAL;
+ if (datalen <= 0 || datalen > 32767 || !data)
+ goto error;
+
+ ret = key_payload_reserve(key, datalen);
+ if (ret < 0)
+ goto error;
+
+ /* attach the data */
+ ret = -ENOMEM;
+ key->payload.data = kmalloc(datalen, GFP_KERNEL);
+ if (!key->payload.data)
+ goto error;
+
+ memcpy(key->payload.data, data, datalen);
+ ret = 0;
+
+ error:
+ return ret;
+
+} /* end user_instantiate() */
+
+/*****************************************************************************/
+/*
+ * duplicate a user defined key
+ */
+static int user_duplicate(struct key *key, const struct key *source)
+{
+ int ret;
+
+ /* just copy the payload */
+ ret = -ENOMEM;
+ key->payload.data = kmalloc(source->datalen, GFP_KERNEL);
+
+ if (key->payload.data) {
+ key->datalen = source->datalen;
+ memcpy(key->payload.data, source->payload.data, source->datalen);
+ ret = 0;
+ }
+
+ return ret;
+
+} /* end user_duplicate() */
+
+/*****************************************************************************/
+/*
+ * update a user defined key
+ */
+static int user_update(struct key *key, const void *data, size_t datalen)
+{
+ void *new, *zap;
+ int ret;
+
+ ret = -EINVAL;
+ if (datalen <= 0 || datalen > 32767 || !data)
+ goto error;
+
+ /* copy the data */
+ ret = -ENOMEM;
+ new = kmalloc(datalen, GFP_KERNEL);
+ if (!new)
+ goto error;
+
+ memcpy(new, data, datalen);
+
+ /* check the quota and attach the new data */
+ zap = new;
+ write_lock(&key->lock);
+
+ ret = key_payload_reserve(key, datalen);
+
+ if (ret == 0) {
+ /* attach the new data, displacing the old */
+ zap = key->payload.data;
+ key->payload.data = new;
+ key->expiry = 0;
+ }
+
+ write_unlock(&key->lock);
+ kfree(zap);
+
+ error:
+ return ret;
+
+} /* end user_update() */
+
+/*****************************************************************************/
+/*
+ * match users on their name
+ */
+static int user_match(const struct key *key, const void *description)
+{
+ return strcmp(key->description, description) == 0;
+
+} /* end user_match() */
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a user
+ */
+static void user_destroy(struct key *key)
+{
+ kfree(key->payload.data);
+
+} /* end user_destroy() */
+
+/*****************************************************************************/
+/*
+ * describe the user
+ */
+static void user_describe(const struct key *key, struct seq_file *m)
+{
+ seq_puts(m, key->description);
+
+ seq_printf(m, ": %u", key->datalen);
+
+} /* end user_describe() */
+
+/*****************************************************************************/
+/*
+ * read the key data
+ */
+static long user_read(const struct key *key,
+ char __user *buffer, size_t buflen)
+{
+ long ret = key->datalen;
+
+ /* we can return the data as is */
+ if (buffer && buflen > 0) {
+ if (buflen > key->datalen)
+ buflen = key->datalen;
+
+ if (copy_to_user(buffer, key->payload.data, buflen) != 0)
+ ret = -EFAULT;
+ }
+
+ return ret;
+
+} /* end user_read() */
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