[PATCHv2 26/59] keys/mktme: Instantiate MKTME keys

Kirill A. Shutemov
2019-07-31T15:09:31Z

From: Alison Schofield <alison.schofield@intel.com>

Instantiate is a Kernel Key Service method invoked when a key is
added (add_key, request_key) by the user.

During instantiation, MKTME allocates an available hardware KeyID
and maps it to the Userspace Key.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
security/keys/mktme_keys.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)

diff --git a/security/keys/mktme_keys.c b/security/keys/mktme_keys.c
index fe119a155235..beca852db01a 100644
--- a/security/keys/mktme_keys.c
+++ b/security/keys/mktme_keys.c
@@ -14,6 +14,7 @@

#include "internal.h"

+static DEFINE_SPINLOCK(mktme_lock);
static unsigned int mktme_available_keyids; /* Free Hardware KeyIDs */

enum mktme_keyid_state {
@@ -31,6 +32,24 @@ struct mktme_mapping {

static struct mktme_mapping *mktme_map;

+int mktme_reserve_keyid(struct key *key)
+{
+ int i;
+
+ if (!mktme_available_keyids)
+ return 0;
+
+ for (i = 1; i <= mktme_nr_keyids(); i++) {
+ if (mktme_map[i].state == KEYID_AVAILABLE) {
+ mktme_map[i].state = KEYID_ASSIGNED;
+ mktme_map[i].key = key;
+ mktme_available_keyids--;
+ return i;
+ }
+ }
+ return 0;
+}
+
enum mktme_opt_id {
OPT_ERROR,
OPT_TYPE,
@@ -43,6 +62,20 @@ static const match_table_t mktme_token = {
{OPT_ERROR, NULL}
};

+/* Key Service Method to create a new key. Payload is preparsed. */
+int mktme_instantiate_key(struct key *key, struct key_preparsed_payload *prep)
+{
+ unsigned long flags;
+ int keyid;
+
+ spin_lock_irqsave(&mktme_lock, flags);
+ keyid = mktme_reserve_keyid(key);
+ spin_unlock_irqrestore(&mktme_lock, flags);
+ if (!keyid)
+ return -ENOKEY;
+ return 0;
+}
+
/* Make sure arguments are correct for the TYPE of key requested */
static int mktme_check_options(u32 *payload, unsigned long token_mask,
enum mktme_type type, enum mktme_alg alg)
@@ -163,6 +196,7 @@ struct key_type key_type_mktme = {
.name = "mktme",
.preparse = mktme_preparse_payload,
.free_preparse = mktme_free_preparsed_payload,
+ .instantiate = mktme_instantiate_key,
.describe = user_describe,
};

--
2.21.0