Merge branch 'security-next-keys' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/security-keys into next-queue

As requested by David.

9 files changed, 198 insertions, 140 deletions

diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index 2d1bb8a..9e1e005 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -773,8 +773,8 @@ static int encrypted_init(struct encrypted_key_payload *epayload,
  *
  * On success, return 0. Otherwise return errno.
  */
-static int encrypted_instantiate(struct key *key, const void *data,
-				 size_t datalen)
+static int encrypted_instantiate(struct key *key,
+				 struct key_preparsed_payload *prep)
 {
 	struct encrypted_key_payload *epayload = NULL;
 	char *datablob = NULL;
@@ -782,16 +782,17 @@ static int encrypted_instantiate(struct key *key, const void *data,
 	char *master_desc = NULL;
 	char *decrypted_datalen = NULL;
 	char *hex_encoded_iv = NULL;
+	size_t datalen = prep->datalen;
 	int ret;
 
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		return -EINVAL;
 
 	datablob = kmalloc(datalen + 1, GFP_KERNEL);
 	if (!datablob)
 		return -ENOMEM;
 	datablob[datalen] = 0;
-	memcpy(datablob, data, datalen);
+	memcpy(datablob, prep->data, datalen);
 	ret = datablob_parse(datablob, &format, &master_desc,
 			     &decrypted_datalen, &hex_encoded_iv);
 	if (ret < 0)
@@ -834,16 +835,17 @@ static void encrypted_rcu_free(struct rcu_head *rcu)
  *
  * On success, return 0. Otherwise return errno.
  */
-static int encrypted_update(struct key *key, const void *data, size_t datalen)
+static int encrypted_update(struct key *key, struct key_preparsed_payload *prep)
 {
 	struct encrypted_key_payload *epayload = key->payload.data;
 	struct encrypted_key_payload *new_epayload;
 	char *buf;
 	char *new_master_desc = NULL;
 	const char *format = NULL;
+	size_t datalen = prep->datalen;
 	int ret = 0;
 
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		return -EINVAL;
 
 	buf = kmalloc(datalen + 1, GFP_KERNEL);
@@ -851,7 +853,7 @@ static int encrypted_update(struct key *key, const void *data, size_t datalen)
 		return -ENOMEM;
 
 	buf[datalen] = 0;
-	memcpy(buf, data, datalen);
+	memcpy(buf, prep->data, datalen);
 	ret = datablob_parse(buf, &format, &new_master_desc, NULL, NULL);
 	if (ret < 0)
 		goto out;
diff --git a/security/keys/key.c b/security/keys/key.c
index 50d96d4..da63a65 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -412,8 +412,7 @@ EXPORT_SYMBOL(key_payload_reserve);
  * key_construction_mutex.
  */
 static int __key_instantiate_and_link(struct key *key,
-				      const void *data,
-				      size_t datalen,
+				      struct key_preparsed_payload *prep,
 				      struct key *keyring,
 				      struct key *authkey,
 				      unsigned long *_prealloc)
@@ -431,7 +430,7 @@ static int __key_instantiate_and_link(struct key *key,
 	/* can't instantiate twice */
 	if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
 		/* instantiate the key */
-		ret = key->type->instantiate(key, data, datalen);
+		ret = key->type->instantiate(key, prep);
 
 		if (ret == 0) {
 			/* mark the key as being instantiated */
@@ -482,22 +481,37 @@ int key_instantiate_and_link(struct key *key,
 			     struct key *keyring,
 			     struct key *authkey)
 {
+	struct key_preparsed_payload prep;
 	unsigned long prealloc;
 	int ret;
 
+	memset(&prep, 0, sizeof(prep));
+	prep.data = data;
+	prep.datalen = datalen;
+	prep.quotalen = key->type->def_datalen;
+	if (key->type->preparse) {
+		ret = key->type->preparse(&prep);
+		if (ret < 0)
+			goto error;
+	}
+
 	if (keyring) {
 		ret = __key_link_begin(keyring, key->type, key->description,
 				       &prealloc);
 		if (ret < 0)
-			return ret;
+			goto error_free_preparse;
 	}
 
-	ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey,
+	ret = __key_instantiate_and_link(key, &prep, keyring, authkey,
 					 &prealloc);
 
 	if (keyring)
 		__key_link_end(keyring, key->type, prealloc);
 
+error_free_preparse:
+	if (key->type->preparse)
+		key->type->free_preparse(&prep);
+error:
 	return ret;
 }
 
@@ -706,7 +720,7 @@ void key_type_put(struct key_type *ktype)
  * if we get an error.
  */
 static inline key_ref_t __key_update(key_ref_t key_ref,
-				     const void *payload, size_t plen)
+				     struct key_preparsed_payload *prep)
 {
 	struct key *key = key_ref_to_ptr(key_ref);
 	int ret;
@@ -722,7 +736,7 @@ static inline key_ref_t __key_update(key_ref_t key_ref,
 
 	down_write(&key->sem);
 
-	ret = key->type->update(key, payload, plen);
+	ret = key->type->update(key, prep);
 	if (ret == 0)
 		/* updating a negative key instantiates it */
 		clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
@@ -774,6 +788,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 			       unsigned long flags)
 {
 	unsigned long prealloc;
+	struct key_preparsed_payload prep;
 	const struct cred *cred = current_cred();
 	struct key_type *ktype;
 	struct key *keyring, *key = NULL;
@@ -789,8 +804,9 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 	}
 
 	key_ref = ERR_PTR(-EINVAL);
-	if (!ktype->match || !ktype->instantiate)
-		goto error_2;
+	if (!ktype->match || !ktype->instantiate ||
+	    (!description && !ktype->preparse))
+		goto error_put_type;
 
 	keyring = key_ref_to_ptr(keyring_ref);
 
@@ -798,18 +814,37 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 
 	key_ref = ERR_PTR(-ENOTDIR);
 	if (keyring->type != &key_type_keyring)
-		goto error_2;
+		goto error_put_type;
+
+	memset(&prep, 0, sizeof(prep));
+	prep.data = payload;
+	prep.datalen = plen;
+	prep.quotalen = ktype->def_datalen;
+	if (ktype->preparse) {
+		ret = ktype->preparse(&prep);
+		if (ret < 0) {
+			key_ref = ERR_PTR(ret);
+			goto error_put_type;
+		}
+		if (!description)
+			description = prep.description;
+		key_ref = ERR_PTR(-EINVAL);
+		if (!description)
+			goto error_free_prep;
+	}
 
 	ret = __key_link_begin(keyring, ktype, description, &prealloc);
-	if (ret < 0)
-		goto error_2;
+	if (ret < 0) {
+		key_ref = ERR_PTR(ret);
+		goto error_free_prep;
+	}
 
 	/* if we're going to allocate a new key, we're going to have
 	 * to modify the keyring */
 	ret = key_permission(keyring_ref, KEY_WRITE);
 	if (ret < 0) {
 		key_ref = ERR_PTR(ret);
-		goto error_3;
+		goto error_link_end;
 	}
 
 	/* if it's possible to update this type of key, search for an existing
@@ -826,13 +861,13 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 	/* if the client doesn't provide, decide on the permissions we want */
 	if (perm == KEY_PERM_UNDEF) {
 		perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
-		perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
+		perm |= KEY_USR_VIEW;
 
 		if (ktype->read)
-			perm |= KEY_POS_READ | KEY_USR_READ;
+			perm |= KEY_POS_READ;
 
 		if (ktype == &key_type_keyring || ktype->update)
-			perm |= KEY_USR_WRITE;
+			perm |= KEY_POS_WRITE;
 	}
 
 	/* allocate a new key */
@@ -840,25 +875,27 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 			perm, flags);
 	if (IS_ERR(key)) {
 		key_ref = ERR_CAST(key);
-		goto error_3;
+		goto error_link_end;
 	}
 
 	/* instantiate it and link it into the target keyring */
-	ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL,
-					 &prealloc);
+	ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &prealloc);
 	if (ret < 0) {
 		key_put(key);
 		key_ref = ERR_PTR(ret);
-		goto error_3;
+		goto error_link_end;
 	}
 
 	key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
 
- error_3:
+error_link_end:
 	__key_link_end(keyring, ktype, prealloc);
- error_2:
+error_free_prep:
+	if (ktype->preparse)
+		ktype->free_preparse(&prep);
+error_put_type:
 	key_type_put(ktype);
- error:
+error:
 	return key_ref;
 
  found_matching_key:
@@ -866,10 +903,9 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 	 * - we can drop the locks first as we have the key pinned
 	 */
 	__key_link_end(keyring, ktype, prealloc);
-	key_type_put(ktype);
 
-	key_ref = __key_update(key_ref, payload, plen);
-	goto error;
+	key_ref = __key_update(key_ref, &prep);
+	goto error_free_prep;
 }
 EXPORT_SYMBOL(key_create_or_update);
 
@@ -888,6 +924,7 @@ EXPORT_SYMBOL(key_create_or_update);
  */
 int key_update(key_ref_t key_ref, const void *payload, size_t plen)
 {
+	struct key_preparsed_payload prep;
 	struct key *key = key_ref_to_ptr(key_ref);
 	int ret;
 
@@ -900,18 +937,31 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen)
 
 	/* attempt to update it if supported */
 	ret = -EOPNOTSUPP;
-	if (key->type->update) {
-		down_write(&key->sem);
-
-		ret = key->type->update(key, payload, plen);
-		if (ret == 0)
-			/* updating a negative key instantiates it */
-			clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
+	if (!key->type->update)
+		goto error;
 
-		up_write(&key->sem);
+	memset(&prep, 0, sizeof(prep));
+	prep.data = payload;
+	prep.datalen = plen;
+	prep.quotalen = key->type->def_datalen;
+	if (key->type->preparse) {
+		ret = key->type->preparse(&prep);
+		if (ret < 0)
+			goto error;
 	}
 
- error:
+	down_write(&key->sem);
+
+	ret = key->type->update(key, &prep);
+	if (ret == 0)
+		/* updating a negative key instantiates it */
+		clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
+
+	up_write(&key->sem);
+
+	if (key->type->preparse)
+		key->type->free_preparse(&prep);
+error:
 	return ret;
 }
 EXPORT_SYMBOL(key_update);
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 3364fbf..6d9d0c7 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -46,6 +46,9 @@ static int key_get_type_from_user(char *type,
  * Extract the description of a new key from userspace and either add it as a
  * new key to the specified keyring or update a matching key in that keyring.
  *
+ * If the description is NULL or an empty string, the key type is asked to
+ * generate one from the payload.
+ *
  * The keyring must be writable so that we can attach the key to it.
  *
  * If successful, the new key's serial number is returned, otherwise an error
@@ -72,10 +75,17 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
 	if (ret < 0)
 		goto error;
 
-	description = strndup_user(_description, PAGE_SIZE);
-	if (IS_ERR(description)) {
-		ret = PTR_ERR(description);
-		goto error;
+	description = NULL;
+	if (_description) {
+		description = strndup_user(_description, PAGE_SIZE);
+		if (IS_ERR(description)) {
+			ret = PTR_ERR(description);
+			goto error;
+		}
+		if (!*description) {
+			kfree(description);
+			description = NULL;
+		}
 	}
 
 	/* pull the payload in if one was supplied */
@@ -1112,12 +1122,12 @@ long keyctl_instantiate_key_iov(key_serial_t id,
 	ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
 				    ARRAY_SIZE(iovstack), iovstack, &iov);
 	if (ret < 0)
-		return ret;
+		goto err;
 	if (ret == 0)
 		goto no_payload_free;
 
 	ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
-
+err:
 	if (iov != iovstack)
 		kfree(iov);
 	return ret;
@@ -1475,7 +1485,8 @@ long keyctl_session_to_parent(void)
 		goto error_keyring;
 	newwork = &cred->rcu;
 
-	cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
+	cred->session_keyring = key_ref_to_ptr(keyring_r);
+	keyring_r = NULL;
 	init_task_work(newwork, key_change_session_keyring);
 
 	me = current;
@@ -1500,7 +1511,7 @@ long keyctl_session_to_parent(void)
 	mycred = current_cred();
 	pcred = __task_cred(parent);
 	if (mycred == pcred ||
-	    mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) {
+	    mycred->session_keyring == pcred->session_keyring) {
 		ret = 0;
 		goto unlock;
 	}
@@ -1516,9 +1527,9 @@ long keyctl_session_to_parent(void)
 		goto unlock;
 
 	/* the keyrings must have the same UID */
-	if ((pcred->tgcred->session_keyring &&
-	     pcred->tgcred->session_keyring->uid != mycred->euid) ||
-	    mycred->tgcred->session_keyring->uid != mycred->euid)
+	if ((pcred->session_keyring &&
+	     pcred->session_keyring->uid != mycred->euid) ||
+	    mycred->session_keyring->uid != mycred->euid)
 		goto unlock;
 
 	/* cancel an already pending keyring replacement */
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 81e7852..9270ba0 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -66,7 +66,7 @@ static inline unsigned keyring_hash(const char *desc)
  * operations.
  */
 static int keyring_instantiate(struct key *keyring,
-			       const void *data, size_t datalen);
+			       struct key_preparsed_payload *prep);
 static int keyring_match(const struct key *keyring, const void *criterion);
 static void keyring_revoke(struct key *keyring);
 static void keyring_destroy(struct key *keyring);
@@ -121,12 +121,12 @@ static void keyring_publish_name(struct key *keyring)
  * Returns 0 on success, -EINVAL if given any data.
  */
 static int keyring_instantiate(struct key *keyring,
-			       const void *data, size_t datalen)
+			       struct key_preparsed_payload *prep)
 {
 	int ret;
 
 	ret = -EINVAL;
-	if (datalen == 0) {
+	if (prep->datalen == 0) {
 		/* make the keyring available by name if it has one */
 		keyring_publish_name(keyring);
 		ret = 0;
@@ -257,17 +257,14 @@ error:
  * Allocate a keyring and link into the destination keyring.
  */
 struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
-			  const struct cred *cred, unsigned long flags,
-			  struct key *dest)
+			  const struct cred *cred, key_perm_t perm,
+			  unsigned long flags, struct key *dest)
 {
 	struct key *keyring;
 	int ret;
 
 	keyring = key_alloc(&key_type_keyring, description,
-			    uid, gid, cred,
-			    (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL,
-			    flags);
-
+			    uid, gid, cred, perm, flags);
 	if (!IS_ERR(keyring)) {
 		ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL);
 		if (ret < 0) {
@@ -278,6 +275,7 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
 
 	return keyring;
 }
+EXPORT_SYMBOL(keyring_alloc);
 
 /**
  * keyring_search_aux - Search a keyring tree for a key matching some criteria
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 54339cf..b58d938 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -46,9 +46,11 @@ int install_user_keyrings(void)
 	struct user_struct *user;
 	const struct cred *cred;
 	struct key *uid_keyring, *session_keyring;
+	key_perm_t user_keyring_perm;
 	char buf[20];
 	int ret;
 
+	user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
 	cred = current_cred();
 	user = cred->user;
 
@@ -72,8 +74,8 @@ int install_user_keyrings(void)
 		uid_keyring = find_keyring_by_name(buf, true);
 		if (IS_ERR(uid_keyring)) {
 			uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1,
-						    cred, KEY_ALLOC_IN_QUOTA,
-						    NULL);
+						    cred, user_keyring_perm,
+						    KEY_ALLOC_IN_QUOTA, NULL);
 			if (IS_ERR(uid_keyring)) {
 				ret = PTR_ERR(uid_keyring);
 				goto error;
@@ -88,7 +90,8 @@ int install_user_keyrings(void)
 		if (IS_ERR(session_keyring)) {
 			session_keyring =
 				keyring_alloc(buf, user->uid, (gid_t) -1,
-					      cred, KEY_ALLOC_IN_QUOTA, NULL);
+					      cred, user_keyring_perm,
+					      KEY_ALLOC_IN_QUOTA, NULL);
 			if (IS_ERR(session_keyring)) {
 				ret = PTR_ERR(session_keyring);
 				goto error_release;
@@ -129,6 +132,7 @@ int install_thread_keyring_to_cred(struct cred *new)
 	struct key *keyring;
 
 	keyring = keyring_alloc("_tid", new->uid, new->gid, new,
+				KEY_POS_ALL | KEY_USR_VIEW,
 				KEY_ALLOC_QUOTA_OVERRUN, NULL);
 	if (IS_ERR(keyring))
 		return PTR_ERR(keyring);
@@ -169,27 +173,18 @@ static int install_thread_keyring(void)
 int install_process_keyring_to_cred(struct cred *new)
 {
 	struct key *keyring;
-	int ret;
 
-	if (new->tgcred->process_keyring)
+	if (new->process_keyring)
 		return -EEXIST;
 
-	keyring = keyring_alloc("_pid", new->uid, new->gid,
-				new, KEY_ALLOC_QUOTA_OVERRUN, NULL);
+	keyring = keyring_alloc("_pid", new->uid, new->gid, new,
+				KEY_POS_ALL | KEY_USR_VIEW,
+				KEY_ALLOC_QUOTA_OVERRUN, NULL);
 	if (IS_ERR(keyring))
 		return PTR_ERR(keyring);
 
-	spin_lock_irq(&new->tgcred->lock);
-	if (!new->tgcred->process_keyring) {
-		new->tgcred->process_keyring = keyring;
-		keyring = NULL;
-		ret = 0;
-	} else {
-		ret = -EEXIST;
-	}
-	spin_unlock_irq(&new->tgcred->lock);
-	key_put(keyring);
-	return ret;
+	new->process_keyring = keyring;
+	return 0;
 }
 
 /*
@@ -230,11 +225,12 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
 	/* create an empty session keyring */
 	if (!keyring) {
 		flags = KEY_ALLOC_QUOTA_OVERRUN;
-		if (cred->tgcred->session_keyring)
+		if (cred->session_keyring)
 			flags = KEY_ALLOC_IN_QUOTA;
 
-		keyring = keyring_alloc("_ses", cred->uid, cred->gid,
-					cred, flags, NULL);
+		keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
+					KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
+					flags, NULL);
 		if (IS_ERR(keyring))
 			return PTR_ERR(keyring);
 	} else {
@@ -242,17 +238,11 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
 	}
 
 	/* install the keyring */
-	spin_lock_irq(&cred->tgcred->lock);
-	old = cred->tgcred->session_keyring;
-	rcu_assign_pointer(cred->tgcred->session_keyring, keyring);
-	spin_unlock_irq(&cred->tgcred->lock);
-
-	/* we're using RCU on the pointer, but there's no point synchronising
-	 * on it if it didn't previously point to anything */
-	if (old) {
-		synchronize_rcu();
+	old = cred->session_keyring;
+	rcu_assign_pointer(cred->session_keyring, keyring);
+
+	if (old)
 		key_put(old);
-	}
 
 	return 0;
 }
@@ -357,8 +347,6 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
 
 		switch (PTR_ERR(key_ref)) {
 		case -EAGAIN: /* no key */
-			if (ret)
-				break;
 		case -ENOKEY: /* negative key */
 			ret = key_ref;
 			break;
@@ -369,9 +357,9 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
 	}
 
 	/* search the process keyring second */
-	if (cred->tgcred->process_keyring) {
+	if (cred->process_keyring) {
 		key_ref = keyring_search_aux(
-			make_key_ref(cred->tgcred->process_keyring, 1),
+			make_key_ref(cred->process_keyring, 1),
 			cred, type, description, match, no_state_check);
 		if (!IS_ERR(key_ref))
 			goto found;
@@ -390,12 +378,10 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
 	}
 
 	/* search the session keyring */
-	if (cred->tgcred->session_keyring) {
+	if (cred->session_keyring) {
 		rcu_read_lock();
 		key_ref = keyring_search_aux(
-			make_key_ref(rcu_dereference(
-					     cred->tgcred->session_keyring),
-				     1),
+			make_key_ref(rcu_dereference(cred->session_keyring), 1),
 			cred, type, description, match, no_state_check);
 		rcu_read_unlock();
 
@@ -565,7 +551,7 @@ try_again:
 		break;
 
 	case KEY_SPEC_PROCESS_KEYRING:
-		if (!cred->tgcred->process_keyring) {
+		if (!cred->process_keyring) {
 			if (!(lflags & KEY_LOOKUP_CREATE))
 				goto error;
 
@@ -577,13 +563,13 @@ try_again:
 			goto reget_creds;
 		}
 
-		key = cred->tgcred->process_keyring;
+		key = cred->process_keyring;
 		atomic_inc(&key->usage);
 		key_ref = make_key_ref(key, 1);
 		break;
 
 	case KEY_SPEC_SESSION_KEYRING:
-		if (!cred->tgcred->session_keyring) {
+		if (!cred->session_keyring) {
 			/* always install a session keyring upon access if one
 			 * doesn't exist yet */
 			ret = install_user_keyrings();
@@ -598,7 +584,7 @@ try_again:
 			if (ret < 0)
 				goto error;
 			goto reget_creds;
-		} else if (cred->tgcred->session_keyring ==
+		} else if (cred->session_keyring ==
 			   cred->user->session_keyring &&
 			   lflags & KEY_LOOKUP_CREATE) {
 			ret = join_session_keyring(NULL);
@@ -608,7 +594,7 @@ try_again:
 		}
 
 		rcu_read_lock();
-		key = rcu_dereference(cred->tgcred->session_keyring);
+		key = rcu_dereference(cred->session_keyring);
 		atomic_inc(&key->usage);
 		rcu_read_unlock();
 		key_ref = make_key_ref(key, 1);
@@ -768,12 +754,6 @@ long join_session_keyring(const char *name)
 	struct key *keyring;
 	long ret, serial;
 
-	/* only permit this if there's a single thread in the thread group -
-	 * this avoids us having to adjust the creds on all threads and risking
-	 * ENOMEM */
-	if (!current_is_single_threaded())
-		return -EMLINK;
-
 	new = prepare_creds();
 	if (!new)
 		return -ENOMEM;
@@ -785,7 +765,7 @@ long join_session_keyring(const char *name)
 		if (ret < 0)
 			goto error;
 
-		serial = new->tgcred->session_keyring->serial;
+		serial = new->session_keyring->serial;
 		ret = commit_creds(new);
 		if (ret == 0)
 			ret = serial;
@@ -799,8 +779,10 @@ long join_session_keyring(const char *name)
 	keyring = find_keyring_by_name(name, false);
 	if (PTR_ERR(keyring) == -ENOKEY) {
 		/* not found - try and create a new one */
-		keyring = keyring_alloc(name, old->uid, old->gid, old,
-					KEY_ALLOC_IN_QUOTA, NULL);
+		keyring = keyring_alloc(
+			name, old->uid, old->gid, old,
+			KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
+			KEY_ALLOC_IN_QUOTA, NULL);
 		if (IS_ERR(keyring)) {
 			ret = PTR_ERR(keyring);
 			goto error2;
@@ -808,6 +790,9 @@ long join_session_keyring(const char *name)
 	} else if (IS_ERR(keyring)) {
 		ret = PTR_ERR(keyring);
 		goto error2;
+	} else if (keyring == new->session_keyring) {
+		ret = 0;
+		goto error2;
 	}
 
 	/* we've got a keyring - now to install it */
@@ -864,8 +849,7 @@ void key_change_session_keyring(struct callback_head *twork)
 
 	new->jit_keyring	= old->jit_keyring;
 	new->thread_keyring	= key_get(old->thread_keyring);
-	new->tgcred->tgid	= old->tgcred->tgid;
-	new->tgcred->process_keyring = key_get(old->tgcred->process_keyring);
+	new->process_keyring	= key_get(old->process_keyring);
 
 	security_transfer_creds(new, old);
 
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 000e750..0ae3a22 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -126,6 +126,7 @@ static int call_sbin_request_key(struct key_construction *cons,
 
 	cred = get_current_cred();
 	keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
+				KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
 				KEY_ALLOC_QUOTA_OVERRUN, NULL);
 	put_cred(cred);
 	if (IS_ERR(keyring)) {
@@ -150,12 +151,12 @@ static int call_sbin_request_key(struct key_construction *cons,
 		cred->thread_keyring ? cred->thread_keyring->serial : 0);
 
 	prkey = 0;
-	if (cred->tgcred->process_keyring)
-		prkey = cred->tgcred->process_keyring->serial;
+	if (cred->process_keyring)
+		prkey = cred->process_keyring->serial;
 	sprintf(keyring_str[1], "%d", prkey);
 
 	rcu_read_lock();
-	session = rcu_dereference(cred->tgcred->session_keyring);
+	session = rcu_dereference(cred->session_keyring);
 	if (!session)
 		session = cred->user->session_keyring;
 	sskey = session->serial;
@@ -297,14 +298,14 @@ static void construct_get_dest_keyring(struct key **_dest_keyring)
 				break;
 
 		case KEY_REQKEY_DEFL_PROCESS_KEYRING:
-			dest_keyring = key_get(cred->tgcred->process_keyring);
+			dest_keyring = key_get(cred->process_keyring);
 			if (dest_keyring)
 				break;
 
 		case KEY_REQKEY_DEFL_SESSION_KEYRING:
 			rcu_read_lock();
 			dest_keyring = key_get(
-				rcu_dereference(cred->tgcred->session_keyring));
+				rcu_dereference(cred->session_keyring));
 			rcu_read_unlock();
 
 			if (dest_keyring)
@@ -347,6 +348,7 @@ static int construct_alloc_key(struct key_type *type,
 	const struct cred *cred = current_cred();
 	unsigned long prealloc;
 	struct key *key;
+	key_perm_t perm;
 	key_ref_t key_ref;
 	int ret;
 
@@ -355,8 +357,15 @@ static int construct_alloc_key(struct key_type *type,
 	*_key = NULL;
 	mutex_lock(&user->cons_lock);
 
+	perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
+	perm |= KEY_USR_VIEW;
+	if (type->read)
+		perm |= KEY_POS_READ;
+	if (type == &key_type_keyring || type->update)
+		perm |= KEY_POS_WRITE;
+
 	key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
-			KEY_POS_ALL, flags);
+			perm, flags);
 	if (IS_ERR(key))
 		goto alloc_failed;
 
diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index 60d4e3f..85730d5 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -19,7 +19,8 @@
 #include <asm/uaccess.h>
 #include "internal.h"
 
-static int request_key_auth_instantiate(struct key *, const void *, size_t);
+static int request_key_auth_instantiate(struct key *,
+					struct key_preparsed_payload *);
 static void request_key_auth_describe(const struct key *, struct seq_file *);
 static void request_key_auth_revoke(struct key *);
 static void request_key_auth_destroy(struct key *);
@@ -42,10 +43,9 @@ struct key_type key_type_request_key_auth = {
  * Instantiate a request-key authorisation key.
  */
 static int request_key_auth_instantiate(struct key *key,
-					const void *data,
-					size_t datalen)
+					struct key_preparsed_payload *prep)
 {
-	key->payload.data = (struct request_key_auth *) data;
+	key->payload.data = (struct request_key_auth *)prep->data;
 	return 0;
 }
 
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index 3f163d0..e13fcf7 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -895,23 +895,24 @@ static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
  *
  * On success, return 0. Otherwise return errno.
  */
-static int trusted_instantiate(struct key *key, const void *data,
-			       size_t datalen)
+static int trusted_instantiate(struct key *key,
+			       struct key_preparsed_payload *prep)
 {
 	struct trusted_key_payload *payload = NULL;
 	struct trusted_key_options *options = NULL;
+	size_t datalen = prep->datalen;
 	char *datablob;
 	int ret = 0;
 	int key_cmd;
 	size_t key_len;
 
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		return -EINVAL;
 
 	datablob = kmalloc(datalen + 1, GFP_KERNEL);
 	if (!datablob)
 		return -ENOMEM;
-	memcpy(datablob, data, datalen);
+	memcpy(datablob, prep->data, datalen);
 	datablob[datalen] = '\0';
 
 	options = trusted_options_alloc();
@@ -981,17 +982,18 @@ static void trusted_rcu_free(struct rcu_head *rcu)
 /*
  * trusted_update - reseal an existing key with new PCR values
  */
-static int trusted_update(struct key *key, const void *data, size_t datalen)
+static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
 {
 	struct trusted_key_payload *p = key->payload.data;
 	struct trusted_key_payload *new_p;
 	struct trusted_key_options *new_o;
+	size_t datalen = prep->datalen;
 	char *datablob;
 	int ret = 0;
 
 	if (!p->migratable)
 		return -EPERM;
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		return -EINVAL;
 
 	datablob = kmalloc(datalen + 1, GFP_KERNEL);
@@ -1008,7 +1010,7 @@ static int trusted_update(struct key *key, const void *data, size_t datalen)
 		goto out;
 	}
 
-	memcpy(datablob, data, datalen);
+	memcpy(datablob, prep->data, datalen);
 	datablob[datalen] = '\0';
 	ret = datablob_parse(datablob, new_p, new_o);
 	if (ret != Opt_update) {
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index c7660a2..55dc889 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -58,13 +58,14 @@ EXPORT_SYMBOL_GPL(key_type_logon);
 /*
  * instantiate a user defined key
  */
-int user_instantiate(struct key *key, const void *data, size_t datalen)
+int user_instantiate(struct key *key, struct key_preparsed_payload *prep)
 {
 	struct user_key_payload *upayload;
+	size_t datalen = prep->datalen;
 	int ret;
 
 	ret = -EINVAL;
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		goto error;
 
 	ret = key_payload_reserve(key, datalen);
@@ -78,7 +79,7 @@ int user_instantiate(struct key *key, const void *data, size_t datalen)
 
 	/* attach the data */
 	upayload->datalen = datalen;
-	memcpy(upayload->data, data, datalen);
+	memcpy(upayload->data, prep->data, datalen);
 	rcu_assign_keypointer(key, upayload);
 	ret = 0;
 
@@ -92,13 +93,14 @@ EXPORT_SYMBOL_GPL(user_instantiate);
  * update a user defined key
  * - the key's semaphore is write-locked
  */
-int user_update(struct key *key, const void *data, size_t datalen)
+int user_update(struct key *key, struct key_preparsed_payload *prep)
 {
 	struct user_key_payload *upayload, *zap;
+	size_t datalen = prep->datalen;
 	int ret;
 
 	ret = -EINVAL;
-	if (datalen <= 0 || datalen > 32767 || !data)
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		goto error;
 
 	/* construct a replacement payload */
@@ -108,7 +110,7 @@ int user_update(struct key *key, const void *data, size_t datalen)
 		goto error;
 
 	upayload->datalen = datalen;
-	memcpy(upayload->data, data, datalen);
+	memcpy(upayload->data, prep->data, datalen);
 
 	/* check the quota and attach the new data */
 	zap = upayload;