1 files changed, 126 insertions, 85 deletions

diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 8d65b3a2812..faa2caeb593 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -11,181 +11,222 @@
 
 #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 <keys/user-type.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);
+static int logon_vet_description(const char *desc);
 
 /*
  * 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,
+	.name			= "user",
+	.def_lookup_type	= KEYRING_SEARCH_LOOKUP_DIRECT,
+	.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);
+
+/*
+ * This key type is essentially the same as key_type_user, but it does
+ * not define a .read op. This is suitable for storing username and
+ * password pairs in the keyring that you do not want to be readable
+ * from userspace.
+ */
+struct key_type key_type_logon = {
+	.name			= "logon",
+	.def_lookup_type	= KEYRING_SEARCH_LOOKUP_DIRECT,
+	.instantiate		= user_instantiate,
+	.update			= user_update,
+	.match			= user_match,
+	.revoke			= user_revoke,
+	.destroy		= user_destroy,
+	.describe		= user_describe,
+	.vet_description	= logon_vet_description,
+};
+EXPORT_SYMBOL_GPL(key_type_logon);
+
 /*
  * instantiate a user defined key
  */
-static int user_instantiate(struct key *key, const void *data, size_t datalen)
+int user_instantiate(struct key *key, struct key_preparsed_payload *prep)
 {
+	struct user_key_payload *upayload;
+	size_t datalen = prep->datalen;
 	int ret;
 
 	ret = -EINVAL;
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->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)
+	upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+	if (!upayload)
 		goto error;
 
-	memcpy(key->payload.data, data, datalen);
+	/* attach the data */
+	upayload->datalen = datalen;
+	memcpy(upayload->data, prep->data, datalen);
+	rcu_assign_keypointer(key, upayload);
 	ret = 0;
 
- error:
+error:
 	return ret;
+}
 
-} /* end user_instantiate() */
+EXPORT_SYMBOL_GPL(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
+ * - the key's semaphore is write-locked
  */
-static int user_update(struct key *key, const void *data, size_t datalen)
+int user_update(struct key *key, struct key_preparsed_payload *prep)
 {
-	void *new, *zap;
+	struct user_key_payload *upayload, *zap;
+	size_t datalen = prep->datalen;
 	int ret;
 
 	ret = -EINVAL;
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		goto error;
 
-	/* copy the data */
+	/* construct a replacement payload */
 	ret = -ENOMEM;
-	new = kmalloc(datalen, GFP_KERNEL);
-	if (!new)
+	upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+	if (!upayload)
 		goto error;
 
-	memcpy(new, data, datalen);
+	upayload->datalen = datalen;
+	memcpy(upayload->data, prep->data, datalen);
 
 	/* check the quota and attach the new data */
-	zap = new;
-	write_lock(&key->lock);
+	zap = upayload;
 
 	ret = key_payload_reserve(key, datalen);
 
 	if (ret == 0) {
 		/* attach the new data, displacing the old */
 		zap = key->payload.data;
-		key->payload.data = new;
+		rcu_assign_keypointer(key, upayload);
 		key->expiry = 0;
 	}
 
-	write_unlock(&key->lock);
-	kfree(zap);
+	if (zap)
+		kfree_rcu(zap, rcu);
 
- error:
+error:
 	return ret;
+}
 
-} /* end user_update() */
+EXPORT_SYMBOL_GPL(user_update);
 
-/*****************************************************************************/
 /*
  * match users on their name
  */
-static int user_match(const struct key *key, const void *description)
+int user_match(const struct key *key, const void *description)
 {
 	return strcmp(key->description, description) == 0;
+}
 
-} /* end user_match() */
+EXPORT_SYMBOL_GPL(user_match);
 
-/*****************************************************************************/
 /*
- * dispose of the data dangling from the corpse of a user
+ * dispose of the links from a revoked keyring
+ * - called with the key sem write-locked
  */
-static void user_destroy(struct key *key)
+void user_revoke(struct key *key)
 {
-	kfree(key->payload.data);
+	struct user_key_payload *upayload = key->payload.data;
+
+	/* clear the quota */
+	key_payload_reserve(key, 0);
 
-} /* end user_destroy() */
+	if (upayload) {
+		rcu_assign_keypointer(key, NULL);
+		kfree_rcu(upayload, rcu);
+	}
+}
+
+EXPORT_SYMBOL(user_revoke);
 
-/*****************************************************************************/
 /*
- * describe the user
+ * dispose of the data dangling from the corpse of a user key
  */
-static void user_describe(const struct key *key, struct seq_file *m)
+void user_destroy(struct key *key)
 {
-	seq_puts(m, key->description);
+	struct user_key_payload *upayload = key->payload.data;
 
-	seq_printf(m, ": %u", key->datalen);
+	kfree(upayload);
+}
 
-} /* end user_describe() */
+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
  */
-static long user_read(const struct key *key,
-		      char __user *buffer, size_t buflen)
+long user_read(const struct key *key, char __user *buffer, size_t buflen)
 {
-	long ret = key->datalen;
+	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 > key->datalen)
-			buflen = key->datalen;
+		if (buflen > upayload->datalen)
+			buflen = upayload->datalen;
 
-		if (copy_to_user(buffer, key->payload.data, buflen) != 0)
+		if (copy_to_user(buffer, upayload->data, buflen) != 0)
 			ret = -EFAULT;
 	}
 
 	return ret;
+}
+
+EXPORT_SYMBOL_GPL(user_read);
+
+/* Vet the description for a "logon" key */
+static int logon_vet_description(const char *desc)
+{
+	char *p;
+
+	/* require a "qualified" description string */
+	p = strchr(desc, ':');
+	if (!p)
+		return -EINVAL;
+
+	/* also reject description with ':' as first char */
+	if (p == desc)
+		return -EINVAL;
 
-} /* end user_read() */
+	return 0;
+}