2 files changed, 156 insertions, 1 deletions

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index bfb0424026aa..cf807654d221 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -11,6 +11,7 @@
  * 2 of the Licence, or (at your option) any later version.
  */
 #include <keys/asymmetric-subtype.h>
+#include <keys/asymmetric-parser.h>
 #include <linux/seq_file.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -18,6 +19,9 @@
 
 MODULE_LICENSE("GPL");
 
+static LIST_HEAD(asymmetric_key_parsers);
+static DECLARE_RWSEM(asymmetric_key_parsers_sem);
+
 /*
  * Match asymmetric keys on (part of) their name
  * We have some shorthand methods for matching keys.  We allow:
@@ -107,12 +111,79 @@ static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
 }
 
 /*
+ * Preparse a asymmetric payload to get format the contents appropriately for the
+ * internal payload to cut down on the number of scans of the data performed.
+ *
+ * We also generate a proposed description from the contents of the key that
+ * can be used to name the key if the user doesn't want to provide one.
+ */
+static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
+{
+        struct asymmetric_key_parser *parser;
+        int ret;
+
+        pr_devel("==>%s()\n", __func__);
+
+        if (prep->datalen == 0)
+                return -EINVAL;
+
+        down_read(&asymmetric_key_parsers_sem);
+
+        ret = -EBADMSG;
+        list_for_each_entry(parser, &asymmetric_key_parsers, link) {
+                pr_debug("Trying parser '%s'\n", parser->name);
+
+                ret = parser->parse(prep);
+                if (ret != -EBADMSG) {
+                        pr_debug("Parser recognised the format (ret %d)\n",
+                                 ret);
+                        break;
+                }
+        }
+
+        up_read(&asymmetric_key_parsers_sem);
+        pr_devel("<==%s() = %d\n", __func__, ret);
+        return ret;
+}
+
+/*
+ * Clean up the preparse data
+ */
+static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
+{
+        struct asymmetric_key_subtype *subtype = prep->type_data[0];
+
+        pr_devel("==>%s()\n", __func__);
+
+        if (subtype) {
+                subtype->destroy(prep->payload);
+                module_put(subtype->owner);
+        }
+        kfree(prep->type_data[1]);
+        kfree(prep->description);
+}
+
+/*
  * Instantiate a asymmetric_key defined key.  The key was preparsed, so we just
  * have to transfer the data here.
  */
 static int asymmetric_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
 {
-        return -EOPNOTSUPP;
+        int ret;
+
+        pr_devel("==>%s()\n", __func__);
+
+        ret = key_payload_reserve(key, prep->quotalen);
+        if (ret == 0) {
+                key->type_data.p[0] = prep->type_data[0];
+                key->type_data.p[1] = prep->type_data[1];
+                key->payload.data = prep->payload;
+                prep->type_data[0] = NULL;
+                prep->type_data[1] = NULL;
+                prep->payload = NULL;
+        }
+        pr_devel("<==%s() = %d\n", __func__, ret);
+        return ret;
 }
 
 /*
@@ -132,6 +203,8 @@ static void asymmetric_key_destroy(struct key *key)
 
 struct key_type key_type_asymmetric = {
         .name           = "asymmetric",
+        .preparse       = asymmetric_key_preparse,
+        .free_preparse  = asymmetric_key_free_preparse,
         .instantiate    = asymmetric_key_instantiate,
         .match          = asymmetric_key_match,
         .destroy        = asymmetric_key_destroy,
@@ -139,6 +212,51 @@ struct key_type key_type_asymmetric = {
 };
 EXPORT_SYMBOL_GPL(key_type_asymmetric);
 
+/**
+ * register_asymmetric_key_parser - Register a asymmetric key blob parser
+ * @parser: The parser to register
+ */
+int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
+{
+        struct asymmetric_key_parser *cursor;
+        int ret;
+
+        down_write(&asymmetric_key_parsers_sem);
+
+        list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
+                if (strcmp(cursor->name, parser->name) == 0) {
+                        pr_err("Asymmetric key parser '%s' already registered\n",
+                               parser->name);
+                        ret = -EEXIST;
+                        goto out;
+                }
+        }
+
+        list_add_tail(&parser->link, &asymmetric_key_parsers);
+
+        pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
+        ret = 0;
+
+out:
+        up_write(&asymmetric_key_parsers_sem);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
+
+/**
+ * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
+ * @parser: The parser to unregister
+ */
+void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
+{
+        down_write(&asymmetric_key_parsers_sem);
+        list_del(&parser->link);
+        up_write(&asymmetric_key_parsers_sem);
+
+        pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
+}
+EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
+
 /*
  * Module stuff
  */
diff --git a/include/keys/asymmetric-parser.h b/include/keys/asymmetric-parser.h
new file mode 100644
index 000000000000..09b3b4807f5c
--- /dev/null
+++ b/include/keys/asymmetric-parser.h
@@ -0,0 +1,37 @@
+/* Asymmetric public-key cryptography data parser
+ *
+ * See Documentation/crypto/asymmetric-keys.txt
+ *
+ * Copyright (C) 2012 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _KEYS_ASYMMETRIC_PARSER_H
+#define _KEYS_ASYMMETRIC_PARSER_H
+
+/*
+ * Key data parser.  Called during key instantiation.
+ */
+struct asymmetric_key_parser {
+        struct list_head        link;
+        struct module           *owner;
+        const char              *name;
+
+        /* Attempt to parse a key from the data blob passed to add_key() or
+         * keyctl_instantiate().  Should also generate a proposed description
+         * that the caller can optionally use for the key.
+         *
+         * Return EBADMSG if not recognised.
+         */
+        int (*parse)(struct key_preparsed_payload *prep);
+};
+
+extern int register_asymmetric_key_parser(struct asymmetric_key_parser *);
+extern void unregister_asymmetric_key_parser(struct asymmetric_key_parser *);
+
+#endif /* _KEYS_ASYMMETRIC_PARSER_H */