KEYS: Merge the type-specific data with the payload data

Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.

Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net

Author: dhowells

Documentation/crypto/asymmetric-keys.txt

@@ -186,7 +186,7 @@ and looks like the following:
 					const struct public_key_signature *sig);
 	};
 
-Asymmetric keys point to this with their type_data[0] member.
+Asymmetric keys point to this with their payload[asym_subtype] member.
 
 The owner and name fields should be set to the owning module and the name of
 the subtype.  Currently, the name is only used for print statements.
@@ -269,8 +269,7 @@ mandatory:
 
 	struct key_preparsed_payload {
 		char		*description;
-		void		*type_data[2];
-		void		*payload;
+		void		*payload[4];
 		const void	*data;
 		size_t		datalen;
 		size_t		quotalen;
@@ -283,16 +282,18 @@ mandatory:
      not theirs.
 
      If the parser is happy with the blob, it should propose a description for
-     the key and attach it to ->description, ->type_data[0] should be set to
-     point to the subtype to be used, ->payload should be set to point to the
-     initialised data for that subtype, ->type_data[1] should point to a hex
-     fingerprint and quotalen should be updated to indicate how much quota this
-     key should account for.
-
-     When clearing up, the data attached to ->type_data[1] and ->description
-     will be kfree()'d and the data attached to ->payload will be passed to the
-     subtype's ->destroy() method to be disposed of.  A module reference for
-     the subtype pointed to by ->type_data[0] will be put.
+     the key and attach it to ->description, ->payload[asym_subtype] should be
+     set to point to the subtype to be used, ->payload[asym_crypto] should be
+     set to point to the initialised data for that subtype,
+     ->payload[asym_key_ids] should point to one or more hex fingerprints and
+     quotalen should be updated to indicate how much quota this key should
+     account for.
+
+     When clearing up, the data attached to ->payload[asym_key_ids] and
+     ->description will be kfree()'d and the data attached to
+     ->payload[asm_crypto] will be passed to the subtype's ->destroy() method
+     to be disposed of.  A module reference for the subtype pointed to by
+     ->payload[asym_subtype] will be put.
 
 
      If the data format is not recognised, -EBADMSG should be returned.  If it

Documentation/security/keys.txt

@@ -1049,12 +1049,12 @@ search a specific keyring, so using keyrings in this way is of limited utility.
 NOTES ON ACCESSING PAYLOAD CONTENTS
 ===================================
 
-The simplest payload is just a number in key->payload.value. In this case,
-there's no need to indulge in RCU or locking when accessing the payload.
+The simplest payload is just data stored in key->payload directly.  In this
+case, there's no need to indulge in RCU or locking when accessing the payload.
 
-More complex payload contents must be allocated and a pointer to them set in
-key->payload.data. One of the following ways must be selected to access the
-data:
+More complex payload contents must be allocated and pointers to them set in the
+key->payload.data[] array.  One of the following ways must be selected to
+access the data:
 
  (1) Unmodifiable key type.
 
@@ -1092,6 +1092,13 @@ data:
      the payload. key->datalen cannot be relied upon to be consistent with the
      payload just dereferenced if the key's semaphore is not held.
 
+     Note that key->payload.data[0] has a shadow that is marked for __rcu
+     usage.  This is called key->payload.rcu_data0.  The following accessors
+     wrap the RCU calls to this element:
+
+	rcu_assign_keypointer(struct key *key, void *data);
+	void *rcu_dereference_key(struct key *key);
+
 
 ===================
 DEFINING A KEY TYPE
@@ -1143,8 +1150,7 @@ The structure has a number of fields, some of which are mandatory:
 
 	struct key_preparsed_payload {
 		char		*description;
-		void		*type_data[2];
-		void		*payload;
+		union key_payload payload;
 		const void	*data;
 		size_t		datalen;
 		size_t		quotalen;
@@ -1160,10 +1166,9 @@ The structure has a number of fields, some of which are mandatory:
      attached as a string to the description field.  This will be used for the
      key description if the caller of add_key() passes NULL or "".
 
-     The method can attach anything it likes to type_data[] and payload.  These
-     are merely passed along to the instantiate() or update() operations.  If
-     set, the expiry time will be applied to the key if it is instantiated from
-     this data.
+     The method can attach anything it likes to payload.  This is merely passed
+     along to the instantiate() or update() operations.  If set, the expiry
+     time will be applied to the key if it is instantiated from this data.
 
      The method should return 0 if successful or a negative error code
      otherwise.
@@ -1172,11 +1177,10 @@ The structure has a number of fields, some of which are mandatory:
  (*) void (*free_preparse)(struct key_preparsed_payload *prep);
 
      This method is only required if the preparse() method is provided,
-     otherwise it is unused.  It cleans up anything attached to the
-     description, type_data and payload fields of the key_preparsed_payload
-     struct as filled in by the preparse() method.  It will always be called
-     after preparse() returns successfully, even if instantiate() or update()
-     succeed.
+     otherwise it is unused.  It cleans up anything attached to the description
+     and payload fields of the key_preparsed_payload struct as filled in by the
+     preparse() method.  It will always be called after preparse() returns
+     successfully, even if instantiate() or update() succeed.
 
 
  (*) int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
@@ -1197,6 +1201,11 @@ The structure has a number of fields, some of which are mandatory:
 
      It is safe to sleep in this method.
 
+     generic_key_instantiate() is provided to simply copy the data from
+     prep->payload.data[] to key->payload.data[], with RCU-safe assignment on
+     the first element.  It will then clear prep->payload.data[] so that the
+     free_preparse method doesn't release the data.
+
 
  (*) int (*update)(struct key *key, const void *data, size_t datalen);
 

crypto/asymmetric_keys/asymmetric_keys.h

@@ -14,8 +14,3 @@ extern struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id);
 extern int __asymmetric_key_hex_to_key_id(const char *id,
 					  struct asymmetric_key_id *match_id,
 					  size_t hexlen);
-static inline
-const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
-{
-	return key->type_data.p[1];
-}

crypto/asymmetric_keys/asymmetric_type.c

@@ -306,26 +306,35 @@ static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
 	return ret;
 }
 
+/*
+ * Clean up the key ID list
+ */
+static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids)
+{
+	int i;
+
+	if (kids) {
+		for (i = 0; i < ARRAY_SIZE(kids->id); i++)
+			kfree(kids->id[i]);
+		kfree(kids);
+	}
+}
+
 /*
  * 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];
-	struct asymmetric_key_ids *kids = prep->type_data[1];
-	int i;
+	struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype];
+	struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids];
 
 	pr_devel("==>%s()\n", __func__);
 
 	if (subtype) {
-		subtype->destroy(prep->payload[0]);
+		subtype->destroy(prep->payload.data[asym_crypto]);
 		module_put(subtype->owner);
 	}
-	if (kids) {
-		for (i = 0; i < ARRAY_SIZE(kids->id); i++)
-			kfree(kids->id[i]);
-		kfree(kids);
-	}
+	asymmetric_key_free_kids(kids);
 	kfree(prep->description);
 }
 
@@ -335,20 +344,19 @@ static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
 static void asymmetric_key_destroy(struct key *key)
 {
 	struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
-	struct asymmetric_key_ids *kids = key->type_data.p[1];
+	struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
+	void *data = key->payload.data[asym_crypto];
+
+	key->payload.data[asym_crypto] = NULL;
+	key->payload.data[asym_subtype] = NULL;
+	key->payload.data[asym_key_ids] = NULL;
 
 	if (subtype) {
-		subtype->destroy(key->payload.data);
+		subtype->destroy(data);
 		module_put(subtype->owner);
-		key->type_data.p[0] = NULL;
 	}
 
-	if (kids) {
-		kfree(kids->id[0]);
-		kfree(kids->id[1]);
-		kfree(kids);
-		key->type_data.p[1] = NULL;
-	}
+	asymmetric_key_free_kids(kids);
 }
 
 struct key_type key_type_asymmetric = {

crypto/asymmetric_keys/public_key.c

@@ -49,7 +49,7 @@ EXPORT_SYMBOL_GPL(pkey_id_type_name);
 static void public_key_describe(const struct key *asymmetric_key,
 				struct seq_file *m)
 {
-	struct public_key *key = asymmetric_key->payload.data;
+	struct public_key *key = asymmetric_key->payload.data[asym_crypto];
 
 	if (key)
 		seq_printf(m, "%s.%s",
@@ -112,7 +112,7 @@ EXPORT_SYMBOL_GPL(public_key_verify_signature);
 static int public_key_verify_signature_2(const struct key *key,
 					 const struct public_key_signature *sig)
 {
-	const struct public_key *pk = key->payload.data;
+	const struct public_key *pk = key->payload.data[asym_crypto];
 	return public_key_verify_signature(pk, sig);
 }
 

crypto/asymmetric_keys/signature.c

@@ -37,7 +37,7 @@ int verify_signature(const struct key *key,
 		return -EINVAL;
 	subtype = asymmetric_key_subtype(key);
 	if (!subtype ||
-	    !key->payload.data)
+	    !key->payload.data[0])
 		return -EINVAL;
 	if (!subtype->verify_signature)
 		return -ENOTSUPP;

crypto/asymmetric_keys/x509_parser.h

@@ -11,6 +11,7 @@
 
 #include <linux/time.h>
 #include <crypto/public_key.h>
+#include <keys/asymmetric-type.h>
 
 struct x509_certificate {
 	struct x509_certificate *next;

crypto/asymmetric_keys/x509_public_key.c

@@ -266,7 +266,8 @@ static int x509_validate_trust(struct x509_certificate *cert,
 	if (!IS_ERR(key))  {
 		if (!use_builtin_keys
 		    || test_bit(KEY_FLAG_BUILTIN, &key->flags))
-			ret = x509_check_signature(key->payload.data, cert);
+			ret = x509_check_signature(key->payload.data[asym_crypto],
+						   cert);
 		key_put(key);
 	}
 	return ret;
@@ -352,9 +353,9 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
 
 	/* We're pinning the module by being linked against it */
 	__module_get(public_key_subtype.owner);
-	prep->type_data[0] = &public_key_subtype;
-	prep->type_data[1] = kids;
-	prep->payload[0] = cert->pub;
+	prep->payload.data[asym_subtype] = &public_key_subtype;
+	prep->payload.data[asym_key_ids] = kids;
+	prep->payload.data[asym_crypto] = cert->pub;
 	prep->description = desc;
 	prep->quotalen = 100;
 

fs/cifs/cifs_spnego.c

@@ -42,7 +42,7 @@ cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
 		goto error;
 
 	/* attach the data */
-	key->payload.data = payload;
+	key->payload.data[0] = payload;
 	ret = 0;
 
 error:
@@ -52,7 +52,7 @@ cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
 static void
 cifs_spnego_key_destroy(struct key *key)
 {
-	kfree(key->payload.data);
+	kfree(key->payload.data[0]);
 }
 
 
@@ -167,7 +167,7 @@ cifs_get_spnego_key(struct cifs_ses *sesInfo)
 
 #ifdef CONFIG_CIFS_DEBUG2
 	if (cifsFYI && !IS_ERR(spnego_key)) {
-		struct cifs_spnego_msg *msg = spnego_key->payload.data;
+		struct cifs_spnego_msg *msg = spnego_key->payload.data[0];
 		cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
 				msg->secblob_len + msg->sesskey_len));
 	}

fs/cifs/cifsacl.c

@@ -58,16 +58,15 @@ cifs_idmap_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
 	 * dereference payload.data!
 	 */
 	if (prep->datalen <= sizeof(key->payload)) {
-		key->payload.value = 0;
-		memcpy(&key->payload.value, prep->data, prep->datalen);
-		key->datalen = prep->datalen;
-		return 0;
+		key->payload.data[0] = NULL;
+		memcpy(&key->payload, prep->data, prep->datalen);
+	} else {
+		payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
+		if (!payload)
+			return -ENOMEM;
+		key->payload.data[0] = payload;
 	}
-	payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
-	if (!payload)
-		return -ENOMEM;
 
-	key->payload.data = payload;
 	key->datalen = prep->datalen;
 	return 0;
 }
@@ -76,7 +75,7 @@ static inline void
 cifs_idmap_key_destroy(struct key *key)
 {
 	if (key->datalen > sizeof(key->payload))
-		kfree(key->payload.data);
+		kfree(key->payload.data[0]);
 }
 
 static struct key_type cifs_idmap_key_type = {
@@ -233,8 +232,8 @@ id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid)
 	 * it could be.
 	 */
 	ksid = sidkey->datalen <= sizeof(sidkey->payload) ?
-		(struct cifs_sid *)&sidkey->payload.value :
-		(struct cifs_sid *)sidkey->payload.data;
+		(struct cifs_sid *)&sidkey->payload :
+		(struct cifs_sid *)sidkey->payload.data[0];
 
 	ksid_size = CIFS_SID_BASE_SIZE + (ksid->num_subauth * sizeof(__le32));
 	if (ksid_size > sidkey->datalen) {
@@ -307,14 +306,14 @@ sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
 	if (sidtype == SIDOWNER) {
 		kuid_t uid;
 		uid_t id;
-		memcpy(&id, &sidkey->payload.value, sizeof(uid_t));
+		memcpy(&id, &sidkey->payload.data[0], sizeof(uid_t));
 		uid = make_kuid(&init_user_ns, id);
 		if (uid_valid(uid))
 			fuid = uid;
 	} else {
 		kgid_t gid;
 		gid_t id;
-		memcpy(&id, &sidkey->payload.value, sizeof(gid_t));
+		memcpy(&id, &sidkey->payload.data[0], sizeof(gid_t));
 		gid = make_kgid(&init_user_ns, id);
 		if (gid_valid(gid))
 			fgid = gid;