aboutsummaryrefslogtreecommitdiff
path: root/crypto
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2012-09-13 15:17:32 +0100
committerRusty Russell <rusty@rustcorp.com.au>2012-10-08 13:50:13 +1030
commit46c6f1776e2f53eebb1fc361946877bab7533227 (patch)
treeef326bf43e5b20dbe88f2506481c6bdb4487e3de /crypto
parent964f3b3bf49eb84b5831121446a28b76de3fb23a (diff)
downloadvexpress-lsk-46c6f1776e2f53eebb1fc361946877bab7533227.tar.gz
KEYS: Asymmetric key pluggable data parsers
The instantiation data passed to the asymmetric key type are expected to be formatted in some way, and there are several possible standard ways to format the data. The two obvious standards are OpenPGP keys and X.509 certificates. The latter is especially useful when dealing with UEFI, and the former might be useful when dealing with, say, eCryptfs. Further, it might be desirable to provide formatted blobs that indicate hardware is to be accessed to retrieve the keys or that the keys live unretrievably in a hardware store, but that the keys can be used by means of the hardware. From userspace, the keys can be loaded using the keyctl command, for example, an X.509 binary certificate: keyctl padd asymmetric foo @s <dhowells.pem or a PGP key: keyctl padd asymmetric bar @s <dhowells.pub or a pointer into the contents of the TPM: keyctl add asymmetric zebra "TPM:04982390582905f8" @s Inside the kernel, pluggable parsers register themselves and then get to examine the payload data to see if they can handle it. If they can, they get to: (1) Propose a name for the key, to be used it the name is "" or NULL. (2) Specify the key subtype. (3) Provide the data for the subtype. The key type asks the parser to do its stuff before a key is allocated and thus before the name is set. If successful, the parser stores the suggested data into the key_preparsed_payload struct, which will be either used (if the key is successfully created and instantiated or updated) or discarded. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/asymmetric_keys/asymmetric_type.c120
1 files changed, 119 insertions, 1 deletions
diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index bfb0424026a..cf807654d22 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
*/