[PATCH 2/9] KEYS: Provide a generic instantiation function

From: David Howells
Date: Mon Nov 04 2013 - 11:39:02 EST


Provide a generic instantiation function for key types that use the preparse
hook. This makes it easier to prereserve key quota before keyrings get locked
to retain the new key.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

crypto/asymmetric_keys/asymmetric_type.c | 25 +------------------------
include/linux/key-type.h | 2 ++
security/keys/key.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index b77eb5304788..c1fe0fcee8e3 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -164,29 +164,6 @@ static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
}

/*
- * 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)
-{
- 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;
-}
-
-/*
* dispose of the data dangling from the corpse of a asymmetric key
*/
static void asymmetric_key_destroy(struct key *key)
@@ -205,7 +182,7 @@ struct key_type key_type_asymmetric = {
.name = "asymmetric",
.preparse = asymmetric_key_preparse,
.free_preparse = asymmetric_key_free_preparse,
- .instantiate = asymmetric_key_instantiate,
+ .instantiate = generic_key_instantiate,
.match = asymmetric_key_match,
.destroy = asymmetric_key_destroy,
.describe = asymmetric_key_describe,
diff --git a/include/linux/key-type.h b/include/linux/key-type.h
index a74c3a84dfdd..88503dca2a57 100644
--- a/include/linux/key-type.h
+++ b/include/linux/key-type.h
@@ -159,5 +159,7 @@ static inline int key_negate_and_link(struct key *key,
return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
}

+extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
+
#endif /* CONFIG_KEYS */
#endif /* _LINUX_KEY_TYPE_H */
diff --git a/security/keys/key.c b/security/keys/key.c
index 55d110f0aced..4ea216652d52 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -1030,6 +1030,36 @@ void key_invalidate(struct key *key)
EXPORT_SYMBOL(key_invalidate);

/**
+ * generic_key_instantiate - Simple instantiation of a key from preparsed data
+ * @key: The key to be instantiated
+ * @prep: The preparsed data to load.
+ *
+ * Instantiate a key from preparsed data. We assume we can just copy the data
+ * in directly and clear the old pointers.
+ *
+ * This can be pointed to directly by the key type instantiate op pointer.
+ */
+int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
+{
+ 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];
+ rcu_assign_keypointer(key, prep->payload);
+ prep->type_data[0] = NULL;
+ prep->type_data[1] = NULL;
+ prep->payload = NULL;
+ }
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+}
+EXPORT_SYMBOL(generic_key_instantiate);
+
+/**
* register_key_type - Register a type of key.
* @ktype: The new key type.
*

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