Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2026 insertions, 0 deletions

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
new file mode 100644
index 000000000..19be69fa4
--- /dev/null
+++ b/security/keys/keyctl.c
@@ -0,0 +1,2026 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Userspace key control operations
+ *
+ * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/key.h>
+#include <linux/keyctl.h>
+#include <linux/fs.h>
+#include <linux/capability.h>
+#include <linux/cred.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/vmalloc.h>
+#include <linux/security.h>
+#include <linux/uio.h>
+#include <linux/uaccess.h>
+#include <keys/request_key_auth-type.h>
+#include "internal.h"
+
+#define KEY_MAX_DESC_SIZE 4096
+
+static const unsigned char keyrings_capabilities[2] = {
+	[0] = (KEYCTL_CAPS0_CAPABILITIES |
+	       (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS)	? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
+	       (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS)	? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
+	       (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE)	? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
+	       (IS_ENABLED(CONFIG_BIG_KEYS)		? KEYCTL_CAPS0_BIG_KEY : 0) |
+	       KEYCTL_CAPS0_INVALIDATE |
+	       KEYCTL_CAPS0_RESTRICT_KEYRING |
+	       KEYCTL_CAPS0_MOVE
+	       ),
+	[1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
+	       KEYCTL_CAPS1_NS_KEY_TAG |
+	       (IS_ENABLED(CONFIG_KEY_NOTIFICATIONS)	? KEYCTL_CAPS1_NOTIFICATIONS : 0)
+	       ),
+};
+
+static int key_get_type_from_user(char *type,
+				  const char __user *_type,
+				  unsigned len)
+{
+	int ret;
+
+	ret = strncpy_from_user(type, _type, len);
+	if (ret < 0)
+		return ret;
+	if (ret == 0 || ret >= len)
+		return -EINVAL;
+	if (type[0] == '.')
+		return -EPERM;
+	type[len - 1] = '\0';
+	return 0;
+}
+
+/*
+ * 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
+ * code is returned.
+ */
+SYSCALL_DEFINE5(add_key, const char __user *, _type,
+		const char __user *, _description,
+		const void __user *, _payload,
+		size_t, plen,
+		key_serial_t, ringid)
+{
+	key_ref_t keyring_ref, key_ref;
+	char type[32], *description;
+	void *payload;
+	long ret;
+
+	ret = -EINVAL;
+	if (plen > 1024 * 1024 - 1)
+		goto error;
+
+	/* draw all the data into kernel space */
+	ret = key_get_type_from_user(type, _type, sizeof(type));
+	if (ret < 0)
+		goto error;
+
+	description = NULL;
+	if (_description) {
+		description = strndup_user(_description, KEY_MAX_DESC_SIZE);
+		if (IS_ERR(description)) {
+			ret = PTR_ERR(description);
+			goto error;
+		}
+		if (!*description) {
+			kfree(description);
+			description = NULL;
+		} else if ((description[0] == '.') &&
+			   (strncmp(type, "keyring", 7) == 0)) {
+			ret = -EPERM;
+			goto error2;
+		}
+	}
+
+	/* pull the payload in if one was supplied */
+	payload = NULL;
+
+	if (plen) {
+		ret = -ENOMEM;
+		payload = kvmalloc(plen, GFP_KERNEL);
+		if (!payload)
+			goto error2;
+
+		ret = -EFAULT;
+		if (copy_from_user(payload, _payload, plen) != 0)
+			goto error3;
+	}
+
+	/* find the target keyring (which must be writable) */
+	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
+	if (IS_ERR(keyring_ref)) {
+		ret = PTR_ERR(keyring_ref);
+		goto error3;
+	}
+
+	/* create or update the requested key and add it to the target
+	 * keyring */
+	key_ref = key_create_or_update(keyring_ref, type, description,
+				       payload, plen, KEY_PERM_UNDEF,
+				       KEY_ALLOC_IN_QUOTA);
+	if (!IS_ERR(key_ref)) {
+		ret = key_ref_to_ptr(key_ref)->serial;
+		key_ref_put(key_ref);
+	}
+	else {
+		ret = PTR_ERR(key_ref);
+	}
+
+	key_ref_put(keyring_ref);
+ error3:
+	kvfree_sensitive(payload, plen);
+ error2:
+	kfree(description);
+ error:
+	return ret;
+}
+
+/*
+ * Search the process keyrings and keyring trees linked from those for a
+ * matching key.  Keyrings must have appropriate Search permission to be
+ * searched.
+ *
+ * If a key is found, it will be attached to the destination keyring if there's
+ * one specified and the serial number of the key will be returned.
+ *
+ * If no key is found, /sbin/request-key will be invoked if _callout_info is
+ * non-NULL in an attempt to create a key.  The _callout_info string will be
+ * passed to /sbin/request-key to aid with completing the request.  If the
+ * _callout_info string is "" then it will be changed to "-".
+ */
+SYSCALL_DEFINE4(request_key, const char __user *, _type,
+		const char __user *, _description,
+		const char __user *, _callout_info,
+		key_serial_t, destringid)
+{
+	struct key_type *ktype;
+	struct key *key;
+	key_ref_t dest_ref;
+	size_t callout_len;
+	char type[32], *description, *callout_info;
+	long ret;
+
+	/* pull the type into kernel space */
+	ret = key_get_type_from_user(type, _type, sizeof(type));
+	if (ret < 0)
+		goto error;
+
+	/* pull the description into kernel space */
+	description = strndup_user(_description, KEY_MAX_DESC_SIZE);
+	if (IS_ERR(description)) {
+		ret = PTR_ERR(description);
+		goto error;
+	}
+
+	/* pull the callout info into kernel space */
+	callout_info = NULL;
+	callout_len = 0;
+	if (_callout_info) {
+		callout_info = strndup_user(_callout_info, PAGE_SIZE);
+		if (IS_ERR(callout_info)) {
+			ret = PTR_ERR(callout_info);
+			goto error2;
+		}
+		callout_len = strlen(callout_info);
+	}
+
+	/* get the destination keyring if specified */
+	dest_ref = NULL;
+	if (destringid) {
+		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
+					   KEY_NEED_WRITE);
+		if (IS_ERR(dest_ref)) {
+			ret = PTR_ERR(dest_ref);
+			goto error3;
+		}
+	}
+
+	/* find the key type */
+	ktype = key_type_lookup(type);
+	if (IS_ERR(ktype)) {
+		ret = PTR_ERR(ktype);
+		goto error4;
+	}
+
+	/* do the search */
+	key = request_key_and_link(ktype, description, NULL, callout_info,
+				   callout_len, NULL, key_ref_to_ptr(dest_ref),
+				   KEY_ALLOC_IN_QUOTA);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error5;
+	}
+
+	/* wait for the key to finish being constructed */
+	ret = wait_for_key_construction(key, 1);
+	if (ret < 0)
+		goto error6;
+
+	ret = key->serial;
+
+error6:
+ 	key_put(key);
+error5:
+	key_type_put(ktype);
+error4:
+	key_ref_put(dest_ref);
+error3:
+	kfree(callout_info);
+error2:
+	kfree(description);
+error:
+	return ret;
+}
+
+/*
+ * Get the ID of the specified process keyring.
+ *
+ * The requested keyring must have search permission to be found.
+ *
+ * If successful, the ID of the requested keyring will be returned.
+ */
+long keyctl_get_keyring_ID(key_serial_t id, int create)
+{
+	key_ref_t key_ref;
+	unsigned long lflags;
+	long ret;
+
+	lflags = create ? KEY_LOOKUP_CREATE : 0;
+	key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		goto error;
+	}
+
+	ret = key_ref_to_ptr(key_ref)->serial;
+	key_ref_put(key_ref);
+error:
+	return ret;
+}
+
+/*
+ * Join a (named) session keyring.
+ *
+ * Create and join an anonymous session keyring or join a named session
+ * keyring, creating it if necessary.  A named session keyring must have Search
+ * permission for it to be joined.  Session keyrings without this permit will
+ * be skipped over.  It is not permitted for userspace to create or join
+ * keyrings whose name begin with a dot.
+ *
+ * If successful, the ID of the joined session keyring will be returned.
+ */
+long keyctl_join_session_keyring(const char __user *_name)
+{
+	char *name;
+	long ret;
+
+	/* fetch the name from userspace */
+	name = NULL;
+	if (_name) {
+		name = strndup_user(_name, KEY_MAX_DESC_SIZE);
+		if (IS_ERR(name)) {
+			ret = PTR_ERR(name);
+			goto error;
+		}
+
+		ret = -EPERM;
+		if (name[0] == '.')
+			goto error_name;
+	}
+
+	/* join the session */
+	ret = join_session_keyring(name);
+error_name:
+	kfree(name);
+error:
+	return ret;
+}
+
+/*
+ * Update a key's data payload from the given data.
+ *
+ * The key must grant the caller Write permission and the key type must support
+ * updating for this to work.  A negative key can be positively instantiated
+ * with this call.
+ *
+ * If successful, 0 will be returned.  If the key type does not support
+ * updating, then -EOPNOTSUPP will be returned.
+ */
+long keyctl_update_key(key_serial_t id,
+		       const void __user *_payload,
+		       size_t plen)
+{
+	key_ref_t key_ref;
+	void *payload;
+	long ret;
+
+	ret = -EINVAL;
+	if (plen > PAGE_SIZE)
+		goto error;
+
+	/* pull the payload in if one was supplied */
+	payload = NULL;
+	if (plen) {
+		ret = -ENOMEM;
+		payload = kvmalloc(plen, GFP_KERNEL);
+		if (!payload)
+			goto error;
+
+		ret = -EFAULT;
+		if (copy_from_user(payload, _payload, plen) != 0)
+			goto error2;
+	}
+
+	/* find the target key (which must be writable) */
+	key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		goto error2;
+	}
+
+	/* update the key */
+	ret = key_update(key_ref, payload, plen);
+
+	key_ref_put(key_ref);
+error2:
+	kvfree_sensitive(payload, plen);
+error:
+	return ret;
+}
+
+/*
+ * Revoke a key.
+ *
+ * The key must be grant the caller Write or Setattr permission for this to
+ * work.  The key type should give up its quota claim when revoked.  The key
+ * and any links to the key will be automatically garbage collected after a
+ * certain amount of time (/proc/sys/kernel/keys/gc_delay).
+ *
+ * Keys with KEY_FLAG_KEEP set should not be revoked.
+ *
+ * If successful, 0 is returned.
+ */
+long keyctl_revoke_key(key_serial_t id)
+{
+	key_ref_t key_ref;
+	struct key *key;
+	long ret;
+
+	key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		if (ret != -EACCES)
+			goto error;
+		key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
+		if (IS_ERR(key_ref)) {
+			ret = PTR_ERR(key_ref);
+			goto error;
+		}
+	}
+
+	key = key_ref_to_ptr(key_ref);
+	ret = 0;
+	if (test_bit(KEY_FLAG_KEEP, &key->flags))
+		ret = -EPERM;
+	else
+		key_revoke(key);
+
+	key_ref_put(key_ref);
+error:
+	return ret;
+}
+
+/*
+ * Invalidate a key.
+ *
+ * The key must be grant the caller Invalidate permission for this to work.
+ * The key and any links to the key will be automatically garbage collected
+ * immediately.
+ *
+ * Keys with KEY_FLAG_KEEP set should not be invalidated.
+ *
+ * If successful, 0 is returned.
+ */
+long keyctl_invalidate_key(key_serial_t id)
+{
+	key_ref_t key_ref;
+	struct key *key;
+	long ret;
+
+	kenter("%d", id);
+
+	key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+
+		/* Root is permitted to invalidate certain special keys */
+		if (capable(CAP_SYS_ADMIN)) {
+			key_ref = lookup_user_key(id, 0, KEY_SYSADMIN_OVERRIDE);
+			if (IS_ERR(key_ref))
+				goto error;
+			if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
+				     &key_ref_to_ptr(key_ref)->flags))
+				goto invalidate;
+			goto error_put;
+		}
+
+		goto error;
+	}
+
+invalidate:
+	key = key_ref_to_ptr(key_ref);
+	ret = 0;
+	if (test_bit(KEY_FLAG_KEEP, &key->flags))
+		ret = -EPERM;
+	else
+		key_invalidate(key);
+error_put:
+	key_ref_put(key_ref);
+error:
+	kleave(" = %ld", ret);
+	return ret;
+}
+
+/*
+ * Clear the specified keyring, creating an empty process keyring if one of the
+ * special keyring IDs is used.
+ *
+ * The keyring must grant the caller Write permission and not have
+ * KEY_FLAG_KEEP set for this to work.  If successful, 0 will be returned.
+ */
+long keyctl_keyring_clear(key_serial_t ringid)
+{
+	key_ref_t keyring_ref;
+	struct key *keyring;
+	long ret;
+
+	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
+	if (IS_ERR(keyring_ref)) {
+		ret = PTR_ERR(keyring_ref);
+
+		/* Root is permitted to invalidate certain special keyrings */
+		if (capable(CAP_SYS_ADMIN)) {
+			keyring_ref = lookup_user_key(ringid, 0,
+						      KEY_SYSADMIN_OVERRIDE);
+			if (IS_ERR(keyring_ref))
+				goto error;
+			if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
+				     &key_ref_to_ptr(keyring_ref)->flags))
+				goto clear;
+			goto error_put;
+		}
+
+		goto error;
+	}
+
+clear:
+	keyring = key_ref_to_ptr(keyring_ref);
+	if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
+		ret = -EPERM;
+	else
+		ret = keyring_clear(keyring);
+error_put:
+	key_ref_put(keyring_ref);
+error:
+	return ret;
+}
+
+/*
+ * Create a link from a keyring to a key if there's no matching key in the
+ * keyring, otherwise replace the link to the matching key with a link to the
+ * new key.
+ *
+ * The key must grant the caller Link permission and the keyring must grant
+ * the caller Write permission.  Furthermore, if an additional link is created,
+ * the keyring's quota will be extended.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
+{
+	key_ref_t keyring_ref, key_ref;
+	long ret;
+
+	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
+	if (IS_ERR(keyring_ref)) {
+		ret = PTR_ERR(keyring_ref);
+		goto error;
+	}
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		goto error2;
+	}
+
+	ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
+
+	key_ref_put(key_ref);
+error2:
+	key_ref_put(keyring_ref);
+error:
+	return ret;
+}
+
+/*
+ * Unlink a key from a keyring.
+ *
+ * The keyring must grant the caller Write permission for this to work; the key
+ * itself need not grant the caller anything.  If the last link to a key is
+ * removed then that key will be scheduled for destruction.
+ *
+ * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
+{
+	key_ref_t keyring_ref, key_ref;
+	struct key *keyring, *key;
+	long ret;
+
+	keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
+	if (IS_ERR(keyring_ref)) {
+		ret = PTR_ERR(keyring_ref);
+		goto error;
+	}
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_PARTIAL, KEY_NEED_UNLINK);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		goto error2;
+	}
+
+	keyring = key_ref_to_ptr(keyring_ref);
+	key = key_ref_to_ptr(key_ref);
+	if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
+	    test_bit(KEY_FLAG_KEEP, &key->flags))
+		ret = -EPERM;
+	else
+		ret = key_unlink(keyring, key);
+
+	key_ref_put(key_ref);
+error2:
+	key_ref_put(keyring_ref);
+error:
+	return ret;
+}
+
+/*
+ * Move a link to a key from one keyring to another, displacing any matching
+ * key from the destination keyring.
+ *
+ * The key must grant the caller Link permission and both keyrings must grant
+ * the caller Write permission.  There must also be a link in the from keyring
+ * to the key.  If both keyrings are the same, nothing is done.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
+			 key_serial_t to_ringid, unsigned int flags)
+{
+	key_ref_t key_ref, from_ref, to_ref;
+	long ret;
+
+	if (flags & ~KEYCTL_MOVE_EXCL)
+		return -EINVAL;
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
+	if (IS_ERR(key_ref))
+		return PTR_ERR(key_ref);
+
+	from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
+	if (IS_ERR(from_ref)) {
+		ret = PTR_ERR(from_ref);
+		goto error2;
+	}
+
+	to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
+	if (IS_ERR(to_ref)) {
+		ret = PTR_ERR(to_ref);
+		goto error3;
+	}
+
+	ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
+		       key_ref_to_ptr(to_ref), flags);
+
+	key_ref_put(to_ref);
+error3:
+	key_ref_put(from_ref);
+error2:
+	key_ref_put(key_ref);
+	return ret;
+}
+
+/*
+ * Return a description of a key to userspace.
+ *
+ * The key must grant the caller View permission for this to work.
+ *
+ * If there's a buffer, we place up to buflen bytes of data into it formatted
+ * in the following way:
+ *
+ *	type;uid;gid;perm;description<NUL>
+ *
+ * If successful, we return the amount of description available, irrespective
+ * of how much we may have copied into the buffer.
+ */
+long keyctl_describe_key(key_serial_t keyid,
+			 char __user *buffer,
+			 size_t buflen)
+{
+	struct key *key, *instkey;
+	key_ref_t key_ref;
+	char *infobuf;
+	long ret;
+	int desclen, infolen;
+
+	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
+	if (IS_ERR(key_ref)) {
+		/* viewing a key under construction is permitted if we have the
+		 * authorisation token handy */
+		if (PTR_ERR(key_ref) == -EACCES) {
+			instkey = key_get_instantiation_authkey(keyid);
+			if (!IS_ERR(instkey)) {
+				key_put(instkey);
+				key_ref = lookup_user_key(keyid,
+							  KEY_LOOKUP_PARTIAL,
+							  KEY_AUTHTOKEN_OVERRIDE);
+				if (!IS_ERR(key_ref))
+					goto okay;
+			}
+		}
+
+		ret = PTR_ERR(key_ref);
+		goto error;
+	}
+
+okay:
+	key = key_ref_to_ptr(key_ref);
+	desclen = strlen(key->description);
+
+	/* calculate how much information we're going to return */
+	ret = -ENOMEM;
+	infobuf = kasprintf(GFP_KERNEL,
+			    "%s;%d;%d;%08x;",
+			    key->type->name,
+			    from_kuid_munged(current_user_ns(), key->uid),
+			    from_kgid_munged(current_user_ns(), key->gid),
+			    key->perm);
+	if (!infobuf)
+		goto error2;
+	infolen = strlen(infobuf);
+	ret = infolen + desclen + 1;
+
+	/* consider returning the data */
+	if (buffer && buflen >= ret) {
+		if (copy_to_user(buffer, infobuf, infolen) != 0 ||
+		    copy_to_user(buffer + infolen, key->description,
+				 desclen + 1) != 0)
+			ret = -EFAULT;
+	}
+
+	kfree(infobuf);
+error2:
+	key_ref_put(key_ref);
+error:
+	return ret;
+}
+
+/*
+ * Search the specified keyring and any keyrings it links to for a matching
+ * key.  Only keyrings that grant the caller Search permission will be searched
+ * (this includes the starting keyring).  Only keys with Search permission can
+ * be found.
+ *
+ * If successful, the found key will be linked to the destination keyring if
+ * supplied and the key has Link permission, and the found key ID will be
+ * returned.
+ */
+long keyctl_keyring_search(key_serial_t ringid,
+			   const char __user *_type,
+			   const char __user *_description,
+			   key_serial_t destringid)
+{
+	struct key_type *ktype;
+	key_ref_t keyring_ref, key_ref, dest_ref;
+	char type[32], *description;
+	long ret;
+
+	/* pull the type and description into kernel space */
+	ret = key_get_type_from_user(type, _type, sizeof(type));
+	if (ret < 0)
+		goto error;
+
+	description = strndup_user(_description, KEY_MAX_DESC_SIZE);
+	if (IS_ERR(description)) {
+		ret = PTR_ERR(description);
+		goto error;
+	}
+
+	/* get the keyring at which to begin the search */
+	keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
+	if (IS_ERR(keyring_ref)) {
+		ret = PTR_ERR(keyring_ref);
+		goto error2;
+	}
+
+	/* get the destination keyring if specified */
+	dest_ref = NULL;
+	if (destringid) {
+		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
+					   KEY_NEED_WRITE);
+		if (IS_ERR(dest_ref)) {
+			ret = PTR_ERR(dest_ref);
+			goto error3;
+		}
+	}
+
+	/* find the key type */
+	ktype = key_type_lookup(type);
+	if (IS_ERR(ktype)) {
+		ret = PTR_ERR(ktype);
+		goto error4;
+	}
+
+	/* do the search */
+	key_ref = keyring_search(keyring_ref, ktype, description, true);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+
+		/* treat lack or presence of a negative key the same */
+		if (ret == -EAGAIN)
+			ret = -ENOKEY;
+		goto error5;
+	}
+
+	/* link the resulting key to the destination keyring if we can */
+	if (dest_ref) {
+		ret = key_permission(key_ref, KEY_NEED_LINK);
+		if (ret < 0)
+			goto error6;
+
+		ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
+		if (ret < 0)
+			goto error6;
+	}
+
+	ret = key_ref_to_ptr(key_ref)->serial;
+
+error6:
+	key_ref_put(key_ref);
+error5:
+	key_type_put(ktype);
+error4:
+	key_ref_put(dest_ref);
+error3:
+	key_ref_put(keyring_ref);
+error2:
+	kfree(description);
+error:
+	return ret;
+}
+
+/*
+ * Call the read method
+ */
+static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
+{
+	long ret;
+
+	down_read(&key->sem);
+	ret = key_validate(key);
+	if (ret == 0)
+		ret = key->type->read(key, buffer, buflen);
+	up_read(&key->sem);
+	return ret;
+}
+
+/*
+ * Read a key's payload.
+ *
+ * The key must either grant the caller Read permission, or it must grant the
+ * caller Search permission when searched for from the process keyrings.
+ *
+ * If successful, we place up to buflen bytes of data into the buffer, if one
+ * is provided, and return the amount of data that is available in the key,
+ * irrespective of how much we copied into the buffer.
+ */
+long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
+{
+	struct key *key;
+	key_ref_t key_ref;
+	long ret;
+	char *key_data = NULL;
+	size_t key_data_len;
+
+	/* find the key first */
+	key_ref = lookup_user_key(keyid, 0, KEY_DEFER_PERM_CHECK);
+	if (IS_ERR(key_ref)) {
+		ret = -ENOKEY;
+		goto out;
+	}
+
+	key = key_ref_to_ptr(key_ref);
+
+	ret = key_read_state(key);
+	if (ret < 0)
+		goto key_put_out; /* Negatively instantiated */
+
+	/* see if we can read it directly */
+	ret = key_permission(key_ref, KEY_NEED_READ);
+	if (ret == 0)
+		goto can_read_key;
+	if (ret != -EACCES)
+		goto key_put_out;
+
+	/* we can't; see if it's searchable from this process's keyrings
+	 * - we automatically take account of the fact that it may be
+	 *   dangling off an instantiation key
+	 */
+	if (!is_key_possessed(key_ref)) {
+		ret = -EACCES;
+		goto key_put_out;
+	}
+
+	/* the key is probably readable - now try to read it */
+can_read_key:
+	if (!key->type->read) {
+		ret = -EOPNOTSUPP;
+		goto key_put_out;
+	}
+
+	if (!buffer || !buflen) {
+		/* Get the key length from the read method */
+		ret = __keyctl_read_key(key, NULL, 0);
+		goto key_put_out;
+	}
+
+	/*
+	 * Read the data with the semaphore held (since we might sleep)
+	 * to protect against the key being updated or revoked.
+	 *
+	 * Allocating a temporary buffer to hold the keys before
+	 * transferring them to user buffer to avoid potential
+	 * deadlock involving page fault and mmap_lock.
+	 *
+	 * key_data_len = (buflen <= PAGE_SIZE)
+	 *		? buflen : actual length of key data
+	 *
+	 * This prevents allocating arbitrary large buffer which can
+	 * be much larger than the actual key length. In the latter case,
+	 * at least 2 passes of this loop is required.
+	 */
+	key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
+	for (;;) {
+		if (key_data_len) {
+			key_data = kvmalloc(key_data_len, GFP_KERNEL);
+			if (!key_data) {
+				ret = -ENOMEM;
+				goto key_put_out;
+			}
+		}
+
+		ret = __keyctl_read_key(key, key_data, key_data_len);
+
+		/*
+		 * Read methods will just return the required length without
+		 * any copying if the provided length isn't large enough.
+		 */
+		if (ret <= 0 || ret > buflen)
+			break;
+
+		/*
+		 * The key may change (unlikely) in between 2 consecutive
+		 * __keyctl_read_key() calls. In this case, we reallocate
+		 * a larger buffer and redo the key read when
+		 * key_data_len < ret <= buflen.
+		 */
+		if (ret > key_data_len) {
+			if (unlikely(key_data))
+				kvfree_sensitive(key_data, key_data_len);
+			key_data_len = ret;
+			continue;	/* Allocate buffer */
+		}
+
+		if (copy_to_user(buffer, key_data, ret))
+			ret = -EFAULT;
+		break;
+	}
+	kvfree_sensitive(key_data, key_data_len);
+
+key_put_out:
+	key_put(key);
+out:
+	return ret;
+}
+
+/*
+ * Change the ownership of a key
+ *
+ * The key must grant the caller Setattr permission for this to work, though
+ * the key need not be fully instantiated yet.  For the UID to be changed, or
+ * for the GID to be changed to a group the caller is not a member of, the
+ * caller must have sysadmin capability.  If either uid or gid is -1 then that
+ * attribute is not changed.
+ *
+ * If the UID is to be changed, the new user must have sufficient quota to
+ * accept the key.  The quota deduction will be removed from the old user to
+ * the new user should the attribute be changed.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
+{
+	struct key_user *newowner, *zapowner = NULL;
+	struct key *key;
+	key_ref_t key_ref;
+	long ret;
+	kuid_t uid;
+	kgid_t gid;
+
+	uid = make_kuid(current_user_ns(), user);
+	gid = make_kgid(current_user_ns(), group);
+	ret = -EINVAL;
+	if ((user != (uid_t) -1) && !uid_valid(uid))
+		goto error;
+	if ((group != (gid_t) -1) && !gid_valid(gid))
+		goto error;
+
+	ret = 0;
+	if (user == (uid_t) -1 && group == (gid_t) -1)
+		goto error;
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
+				  KEY_NEED_SETATTR);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		goto error;
+	}
+
+	key = key_ref_to_ptr(key_ref);
+
+	/* make the changes with the locks held to prevent chown/chown races */
+	ret = -EACCES;
+	down_write(&key->sem);
+
+	{
+		bool is_privileged_op = false;
+
+		/* only the sysadmin can chown a key to some other UID */
+		if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
+			is_privileged_op = true;
+
+		/* only the sysadmin can set the key's GID to a group other
+		 * than one of those that the current process subscribes to */
+		if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
+			is_privileged_op = true;
+
+		if (is_privileged_op && !capable(CAP_SYS_ADMIN))
+			goto error_put;
+	}
+
+	/* change the UID */
+	if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
+		ret = -ENOMEM;
+		newowner = key_user_lookup(uid);
+		if (!newowner)
+			goto error_put;
+
+		/* transfer the quota burden to the new user */
+		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
+			unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
+				key_quota_root_maxkeys : key_quota_maxkeys;
+			unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
+				key_quota_root_maxbytes : key_quota_maxbytes;
+
+			spin_lock(&newowner->lock);
+			if (newowner->qnkeys + 1 > maxkeys ||
+			    newowner->qnbytes + key->quotalen > maxbytes ||
+			    newowner->qnbytes + key->quotalen <
+			    newowner->qnbytes)
+				goto quota_overrun;
+
+			newowner->qnkeys++;
+			newowner->qnbytes += key->quotalen;
+			spin_unlock(&newowner->lock);
+
+			spin_lock(&key->user->lock);
+			key->user->qnkeys--;
+			key->user->qnbytes -= key->quotalen;
+			spin_unlock(&key->user->lock);
+		}
+
+		atomic_dec(&key->user->nkeys);
+		atomic_inc(&newowner->nkeys);
+
+		if (key->state != KEY_IS_UNINSTANTIATED) {
+			atomic_dec(&key->user->nikeys);
+			atomic_inc(&newowner->nikeys);
+		}
+
+		zapowner = key->user;
+		key->user = newowner;
+		key->uid = uid;
+	}
+
+	/* change the GID */
+	if (group != (gid_t) -1)
+		key->gid = gid;
+
+	notify_key(key, NOTIFY_KEY_SETATTR, 0);
+	ret = 0;
+
+error_put:
+	up_write(&key->sem);
+	key_put(key);
+	if (zapowner)
+		key_user_put(zapowner);
+error:
+	return ret;
+
+quota_overrun:
+	spin_unlock(&newowner->lock);
+	zapowner = newowner;
+	ret = -EDQUOT;
+	goto error_put;
+}
+
+/*
+ * Change the permission mask on a key.
+ *
+ * The key must grant the caller Setattr permission for this to work, though
+ * the key need not be fully instantiated yet.  If the caller does not have
+ * sysadmin capability, it may only change the permission on keys that it owns.
+ */
+long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
+{
+	struct key *key;
+	key_ref_t key_ref;
+	long ret;
+
+	ret = -EINVAL;
+	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
+		goto error;
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
+				  KEY_NEED_SETATTR);
+	if (IS_ERR(key_ref)) {
+		ret = PTR_ERR(key_ref);
+		goto error;
+	}
+
+	key = key_ref_to_ptr(key_ref);
+
+	/* make the changes with the locks held to prevent chown/chmod races */
+	ret = -EACCES;
+	down_write(&key->sem);
+
+	/* if we're not the sysadmin, we can only change a key that we own */
+	if (uid_eq(key->uid, current_fsuid()) || capable(CAP_SYS_ADMIN)) {
+		key->perm = perm;
+		notify_key(key, NOTIFY_KEY_SETATTR, 0);
+		ret = 0;
+	}
+
+	up_write(&key->sem);
+	key_put(key);
+error:
+	return ret;
+}
+
+/*
+ * Get the destination keyring for instantiation and check that the caller has
+ * Write permission on it.
+ */
+static long get_instantiation_keyring(key_serial_t ringid,
+				      struct request_key_auth *rka,
+				      struct key **_dest_keyring)
+{
+	key_ref_t dkref;
+
+	*_dest_keyring = NULL;
+
+	/* just return a NULL pointer if we weren't asked to make a link */
+	if (ringid == 0)
+		return 0;
+
+	/* if a specific keyring is nominated by ID, then use that */
+	if (ringid > 0) {
+		dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
+		if (IS_ERR(dkref))
+			return PTR_ERR(dkref);
+		*_dest_keyring = key_ref_to_ptr(dkref);
+		return 0;
+	}
+
+	if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
+		return -EINVAL;
+
+	/* otherwise specify the destination keyring recorded in the
+	 * authorisation key (any KEY_SPEC_*_KEYRING) */
+	if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
+		*_dest_keyring = key_get(rka->dest_keyring);
+		return 0;
+	}
+
+	return -ENOKEY;
+}
+
+/*
+ * Change the request_key authorisation key on the current process.
+ */
+static int keyctl_change_reqkey_auth(struct key *key)
+{
+	struct cred *new;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	key_put(new->request_key_auth);
+	new->request_key_auth = key_get(key);
+
+	return commit_creds(new);
+}
+
+/*
+ * Instantiate a key with the specified payload and link the key into the
+ * destination keyring if one is given.
+ *
+ * The caller must have the appropriate instantiation permit set for this to
+ * work (see keyctl_assume_authority).  No other permissions are required.
+ *
+ * If successful, 0 will be returned.
+ */
+static long keyctl_instantiate_key_common(key_serial_t id,
+				   struct iov_iter *from,
+				   key_serial_t ringid)
+{
+	const struct cred *cred = current_cred();
+	struct request_key_auth *rka;
+	struct key *instkey, *dest_keyring;
+	size_t plen = from ? iov_iter_count(from) : 0;
+	void *payload;
+	long ret;
+
+	kenter("%d,,%zu,%d", id, plen, ringid);
+
+	if (!plen)
+		from = NULL;
+
+	ret = -EINVAL;
+	if (plen > 1024 * 1024 - 1)
+		goto error;
+
+	/* the appropriate instantiation authorisation key must have been
+	 * assumed before calling this */
+	ret = -EPERM;
+	instkey = cred->request_key_auth;
+	if (!instkey)
+		goto error;
+
+	rka = instkey->payload.data[0];
+	if (rka->target_key->serial != id)
+		goto error;
+
+	/* pull the payload in if one was supplied */
+	payload = NULL;
+
+	if (from) {
+		ret = -ENOMEM;
+		payload = kvmalloc(plen, GFP_KERNEL);
+		if (!payload)
+			goto error;
+
+		ret = -EFAULT;
+		if (!copy_from_iter_full(payload, plen, from))
+			goto error2;
+	}
+
+	/* find the destination keyring amongst those belonging to the
+	 * requesting task */
+	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
+	if (ret < 0)
+		goto error2;
+
+	/* instantiate the key and link it into a keyring */
+	ret = key_instantiate_and_link(rka->target_key, payload, plen,
+				       dest_keyring, instkey);
+
+	key_put(dest_keyring);
+
+	/* discard the assumed authority if it's just been disabled by
+	 * instantiation of the key */
+	if (ret == 0)
+		keyctl_change_reqkey_auth(NULL);
+
+error2:
+	kvfree_sensitive(payload, plen);
+error:
+	return ret;
+}
+
+/*
+ * Instantiate a key with the specified payload and link the key into the
+ * destination keyring if one is given.
+ *
+ * The caller must have the appropriate instantiation permit set for this to
+ * work (see keyctl_assume_authority).  No other permissions are required.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_instantiate_key(key_serial_t id,
+			    const void __user *_payload,
+			    size_t plen,
+			    key_serial_t ringid)
+{
+	if (_payload && plen) {
+		struct iovec iov;
+		struct iov_iter from;
+		int ret;
+
+		ret = import_single_range(ITER_SOURCE, (void __user *)_payload, plen,
+					  &iov, &from);
+		if (unlikely(ret))
+			return ret;
+
+		return keyctl_instantiate_key_common(id, &from, ringid);
+	}
+
+	return keyctl_instantiate_key_common(id, NULL, ringid);
+}
+
+/*
+ * Instantiate a key with the specified multipart payload and link the key into
+ * the destination keyring if one is given.
+ *
+ * The caller must have the appropriate instantiation permit set for this to
+ * work (see keyctl_assume_authority).  No other permissions are required.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_instantiate_key_iov(key_serial_t id,
+				const struct iovec __user *_payload_iov,
+				unsigned ioc,
+				key_serial_t ringid)
+{
+	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
+	struct iov_iter from;
+	long ret;
+
+	if (!_payload_iov)
+		ioc = 0;
+
+	ret = import_iovec(ITER_SOURCE, _payload_iov, ioc,
+				    ARRAY_SIZE(iovstack), &iov, &from);
+	if (ret < 0)
+		return ret;
+	ret = keyctl_instantiate_key_common(id, &from, ringid);
+	kfree(iov);
+	return ret;
+}
+
+/*
+ * Negatively instantiate the key with the given timeout (in seconds) and link
+ * the key into the destination keyring if one is given.
+ *
+ * The caller must have the appropriate instantiation permit set for this to
+ * work (see keyctl_assume_authority).  No other permissions are required.
+ *
+ * The key and any links to the key will be automatically garbage collected
+ * after the timeout expires.
+ *
+ * Negative keys are used to rate limit repeated request_key() calls by causing
+ * them to return -ENOKEY until the negative key expires.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
+{
+	return keyctl_reject_key(id, timeout, ENOKEY, ringid);
+}
+
+/*
+ * Negatively instantiate the key with the given timeout (in seconds) and error
+ * code and link the key into the destination keyring if one is given.
+ *
+ * The caller must have the appropriate instantiation permit set for this to
+ * work (see keyctl_assume_authority).  No other permissions are required.
+ *
+ * The key and any links to the key will be automatically garbage collected
+ * after the timeout expires.
+ *
+ * Negative keys are used to rate limit repeated request_key() calls by causing
+ * them to return the specified error code until the negative key expires.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
+		       key_serial_t ringid)
+{
+	const struct cred *cred = current_cred();
+	struct request_key_auth *rka;
+	struct key *instkey, *dest_keyring;
+	long ret;
+
+	kenter("%d,%u,%u,%d", id, timeout, error, ringid);
+
+	/* must be a valid error code and mustn't be a kernel special */
+	if (error <= 0 ||
+	    error >= MAX_ERRNO ||
+	    error == ERESTARTSYS ||
+	    error == ERESTARTNOINTR ||
+	    error == ERESTARTNOHAND ||
+	    error == ERESTART_RESTARTBLOCK)
+		return -EINVAL;
+
+	/* the appropriate instantiation authorisation key must have been
+	 * assumed before calling this */
+	ret = -EPERM;
+	instkey = cred->request_key_auth;
+	if (!instkey)
+		goto error;
+
+	rka = instkey->payload.data[0];
+	if (rka->target_key->serial != id)
+		goto error;
+
+	/* find the destination keyring if present (which must also be
+	 * writable) */
+	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
+	if (ret < 0)
+		goto error;
+
+	/* instantiate the key and link it into a keyring */
+	ret = key_reject_and_link(rka->target_key, timeout, error,
+				  dest_keyring, instkey);
+
+	key_put(dest_keyring);
+
+	/* discard the assumed authority if it's just been disabled by
+	 * instantiation of the key */
+	if (ret == 0)
+		keyctl_change_reqkey_auth(NULL);
+
+error:
+	return ret;
+}
+
+/*
+ * Read or set the default keyring in which request_key() will cache keys and
+ * return the old setting.
+ *
+ * If a thread or process keyring is specified then it will be created if it
+ * doesn't yet exist.  The old setting will be returned if successful.
+ */
+long keyctl_set_reqkey_keyring(int reqkey_defl)
+{
+	struct cred *new;
+	int ret, old_setting;
+
+	old_setting = current_cred_xxx(jit_keyring);
+
+	if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
+		return old_setting;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	switch (reqkey_defl) {
+	case KEY_REQKEY_DEFL_THREAD_KEYRING:
+		ret = install_thread_keyring_to_cred(new);
+		if (ret < 0)
+			goto error;
+		goto set;
+
+	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
+		ret = install_process_keyring_to_cred(new);
+		if (ret < 0)
+			goto error;
+		goto set;
+
+	case KEY_REQKEY_DEFL_DEFAULT:
+	case KEY_REQKEY_DEFL_SESSION_KEYRING:
+	case KEY_REQKEY_DEFL_USER_KEYRING:
+	case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
+	case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
+		goto set;
+
+	case KEY_REQKEY_DEFL_NO_CHANGE:
+	case KEY_REQKEY_DEFL_GROUP_KEYRING:
+	default:
+		ret = -EINVAL;
+		goto error;
+	}
+
+set:
+	new->jit_keyring = reqkey_defl;
+	commit_creds(new);
+	return old_setting;
+error:
+	abort_creds(new);
+	return ret;
+}
+
+/*
+ * Set or clear the timeout on a key.
+ *
+ * Either the key must grant the caller Setattr permission or else the caller
+ * must hold an instantiation authorisation token for the key.
+ *
+ * The timeout is either 0 to clear the timeout, or a number of seconds from
+ * the current time.  The key and any links to the key will be automatically
+ * garbage collected after the timeout expires.
+ *
+ * Keys with KEY_FLAG_KEEP set should not be timed out.
+ *
+ * If successful, 0 is returned.
+ */
+long keyctl_set_timeout(key_serial_t id, unsigned timeout)
+{
+	struct key *key, *instkey;
+	key_ref_t key_ref;
+	long ret;
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
+				  KEY_NEED_SETATTR);
+	if (IS_ERR(key_ref)) {
+		/* setting the timeout on a key under construction is permitted
+		 * if we have the authorisation token handy */
+		if (PTR_ERR(key_ref) == -EACCES) {
+			instkey = key_get_instantiation_authkey(id);
+			if (!IS_ERR(instkey)) {
+				key_put(instkey);
+				key_ref = lookup_user_key(id,
+							  KEY_LOOKUP_PARTIAL,
+							  KEY_AUTHTOKEN_OVERRIDE);
+				if (!IS_ERR(key_ref))
+					goto okay;
+			}
+		}
+
+		ret = PTR_ERR(key_ref);
+		goto error;
+	}
+
+okay:
+	key = key_ref_to_ptr(key_ref);
+	ret = 0;
+	if (test_bit(KEY_FLAG_KEEP, &key->flags)) {
+		ret = -EPERM;
+	} else {
+		key_set_timeout(key, timeout);
+		notify_key(key, NOTIFY_KEY_SETATTR, 0);
+	}
+	key_put(key);
+
+error:
+	return ret;
+}
+
+/*
+ * Assume (or clear) the authority to instantiate the specified key.
+ *
+ * This sets the authoritative token currently in force for key instantiation.
+ * This must be done for a key to be instantiated.  It has the effect of making
+ * available all the keys from the caller of the request_key() that created a
+ * key to request_key() calls made by the caller of this function.
+ *
+ * The caller must have the instantiation key in their process keyrings with a
+ * Search permission grant available to the caller.
+ *
+ * If the ID given is 0, then the setting will be cleared and 0 returned.
+ *
+ * If the ID given has a matching an authorisation key, then that key will be
+ * set and its ID will be returned.  The authorisation key can be read to get
+ * the callout information passed to request_key().
+ */
+long keyctl_assume_authority(key_serial_t id)
+{
+	struct key *authkey;
+	long ret;
+
+	/* special key IDs aren't permitted */
+	ret = -EINVAL;
+	if (id < 0)
+		goto error;
+
+	/* we divest ourselves of authority if given an ID of 0 */
+	if (id == 0) {
+		ret = keyctl_change_reqkey_auth(NULL);
+		goto error;
+	}
+
+	/* attempt to assume the authority temporarily granted to us whilst we
+	 * instantiate the specified key
+	 * - the authorisation key must be in the current task's keyrings
+	 *   somewhere
+	 */
+	authkey = key_get_instantiation_authkey(id);
+	if (IS_ERR(authkey)) {
+		ret = PTR_ERR(authkey);
+		goto error;
+	}
+
+	ret = keyctl_change_reqkey_auth(authkey);
+	if (ret == 0)
+		ret = authkey->serial;
+	key_put(authkey);
+error:
+	return ret;
+}
+
+/*
+ * Get a key's the LSM security label.
+ *
+ * The key must grant the caller View permission for this to work.
+ *
+ * If there's a buffer, then up to buflen bytes of data will be placed into it.
+ *
+ * If successful, the amount of information available will be returned,
+ * irrespective of how much was copied (including the terminal NUL).
+ */
+long keyctl_get_security(key_serial_t keyid,
+			 char __user *buffer,
+			 size_t buflen)
+{
+	struct key *key, *instkey;
+	key_ref_t key_ref;
+	char *context;
+	long ret;
+
+	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
+	if (IS_ERR(key_ref)) {
+		if (PTR_ERR(key_ref) != -EACCES)
+			return PTR_ERR(key_ref);
+
+		/* viewing a key under construction is also permitted if we
+		 * have the authorisation token handy */
+		instkey = key_get_instantiation_authkey(keyid);
+		if (IS_ERR(instkey))
+			return PTR_ERR(instkey);
+		key_put(instkey);
+
+		key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL,
+					  KEY_AUTHTOKEN_OVERRIDE);
+		if (IS_ERR(key_ref))
+			return PTR_ERR(key_ref);
+	}
+
+	key = key_ref_to_ptr(key_ref);
+	ret = security_key_getsecurity(key, &context);
+	if (ret == 0) {
+		/* if no information was returned, give userspace an empty
+		 * string */
+		ret = 1;
+		if (buffer && buflen > 0 &&
+		    copy_to_user(buffer, "", 1) != 0)
+			ret = -EFAULT;
+	} else if (ret > 0) {
+		/* return as much data as there's room for */
+		if (buffer && buflen > 0) {
+			if (buflen > ret)
+				buflen = ret;
+
+			if (copy_to_user(buffer, context, buflen) != 0)
+				ret = -EFAULT;
+		}
+
+		kfree(context);
+	}
+
+	key_ref_put(key_ref);
+	return ret;
+}
+
+/*
+ * Attempt to install the calling process's session keyring on the process's
+ * parent process.
+ *
+ * The keyring must exist and must grant the caller LINK permission, and the
+ * parent process must be single-threaded and must have the same effective
+ * ownership as this process and mustn't be SUID/SGID.
+ *
+ * The keyring will be emplaced on the parent when it next resumes userspace.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_session_to_parent(void)
+{
+	struct task_struct *me, *parent;
+	const struct cred *mycred, *pcred;
+	struct callback_head *newwork, *oldwork;
+	key_ref_t keyring_r;
+	struct cred *cred;
+	int ret;
+
+	keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
+	if (IS_ERR(keyring_r))
+		return PTR_ERR(keyring_r);
+
+	ret = -ENOMEM;
+
+	/* our parent is going to need a new cred struct, a new tgcred struct
+	 * and new security data, so we allocate them here to prevent ENOMEM in
+	 * our parent */
+	cred = cred_alloc_blank();
+	if (!cred)
+		goto error_keyring;
+	newwork = &cred->rcu;
+
+	cred->session_keyring = key_ref_to_ptr(keyring_r);
+	keyring_r = NULL;
+	init_task_work(newwork, key_change_session_keyring);
+
+	me = current;
+	rcu_read_lock();
+	write_lock_irq(&tasklist_lock);
+
+	ret = -EPERM;
+	oldwork = NULL;
+	parent = rcu_dereference_protected(me->real_parent,
+					   lockdep_is_held(&tasklist_lock));
+
+	/* the parent mustn't be init and mustn't be a kernel thread */
+	if (parent->pid <= 1 || !parent->mm)
+		goto unlock;
+
+	/* the parent must be single threaded */
+	if (!thread_group_empty(parent))
+		goto unlock;
+
+	/* the parent and the child must have different session keyrings or
+	 * there's no point */
+	mycred = current_cred();
+	pcred = __task_cred(parent);
+	if (mycred == pcred ||
+	    mycred->session_keyring == pcred->session_keyring) {
+		ret = 0;
+		goto unlock;
+	}
+
+	/* the parent must have the same effective ownership and mustn't be
+	 * SUID/SGID */
+	if (!uid_eq(pcred->uid,	 mycred->euid) ||
+	    !uid_eq(pcred->euid, mycred->euid) ||
+	    !uid_eq(pcred->suid, mycred->euid) ||
+	    !gid_eq(pcred->gid,	 mycred->egid) ||
+	    !gid_eq(pcred->egid, mycred->egid) ||
+	    !gid_eq(pcred->sgid, mycred->egid))
+		goto unlock;
+
+	/* the keyrings must have the same UID */
+	if ((pcred->session_keyring &&
+	     !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
+	    !uid_eq(mycred->session_keyring->uid, mycred->euid))
+		goto unlock;
+
+	/* cancel an already pending keyring replacement */
+	oldwork = task_work_cancel(parent, key_change_session_keyring);
+
+	/* the replacement session keyring is applied just prior to userspace
+	 * restarting */
+	ret = task_work_add(parent, newwork, TWA_RESUME);
+	if (!ret)
+		newwork = NULL;
+unlock:
+	write_unlock_irq(&tasklist_lock);
+	rcu_read_unlock();
+	if (oldwork)
+		put_cred(container_of(oldwork, struct cred, rcu));
+	if (newwork)
+		put_cred(cred);
+	return ret;
+
+error_keyring:
+	key_ref_put(keyring_r);
+	return ret;
+}
+
+/*
+ * Apply a restriction to a given keyring.
+ *
+ * The caller must have Setattr permission to change keyring restrictions.
+ *
+ * The requested type name may be a NULL pointer to reject all attempts
+ * to link to the keyring.  In this case, _restriction must also be NULL.
+ * Otherwise, both _type and _restriction must be non-NULL.
+ *
+ * Returns 0 if successful.
+ */
+long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
+			     const char __user *_restriction)
+{
+	key_ref_t key_ref;
+	char type[32];
+	char *restriction = NULL;
+	long ret;
+
+	key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
+	if (IS_ERR(key_ref))
+		return PTR_ERR(key_ref);
+
+	ret = -EINVAL;
+	if (_type) {
+		if (!_restriction)
+			goto error;
+
+		ret = key_get_type_from_user(type, _type, sizeof(type));
+		if (ret < 0)
+			goto error;
+
+		restriction = strndup_user(_restriction, PAGE_SIZE);
+		if (IS_ERR(restriction)) {
+			ret = PTR_ERR(restriction);
+			goto error;
+		}
+	} else {
+		if (_restriction)
+			goto error;
+	}
+
+	ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
+	kfree(restriction);
+error:
+	key_ref_put(key_ref);
+	return ret;
+}
+
+#ifdef CONFIG_KEY_NOTIFICATIONS
+/*
+ * Watch for changes to a key.
+ *
+ * The caller must have View permission to watch a key or keyring.
+ */
+long keyctl_watch_key(key_serial_t id, int watch_queue_fd, int watch_id)
+{
+	struct watch_queue *wqueue;
+	struct watch_list *wlist = NULL;
+	struct watch *watch = NULL;
+	struct key *key;
+	key_ref_t key_ref;
+	long ret;
+
+	if (watch_id < -1 || watch_id > 0xff)
+		return -EINVAL;
+
+	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_VIEW);
+	if (IS_ERR(key_ref))
+		return PTR_ERR(key_ref);
+	key = key_ref_to_ptr(key_ref);
+
+	wqueue = get_watch_queue(watch_queue_fd);
+	if (IS_ERR(wqueue)) {
+		ret = PTR_ERR(wqueue);
+		goto err_key;
+	}
+
+	if (watch_id >= 0) {
+		ret = -ENOMEM;
+		if (!key->watchers) {
+			wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
+			if (!wlist)
+				goto err_wqueue;
+			init_watch_list(wlist, NULL);
+		}
+
+		watch = kzalloc(sizeof(*watch), GFP_KERNEL);
+		if (!watch)
+			goto err_wlist;
+
+		init_watch(watch, wqueue);
+		watch->id	= key->serial;
+		watch->info_id	= (u32)watch_id << WATCH_INFO_ID__SHIFT;
+
+		ret = security_watch_key(key);
+		if (ret < 0)
+			goto err_watch;
+
+		down_write(&key->sem);
+		if (!key->watchers) {
+			key->watchers = wlist;
+			wlist = NULL;
+		}
+
+		ret = add_watch_to_object(watch, key->watchers);
+		up_write(&key->sem);
+
+		if (ret == 0)
+			watch = NULL;
+	} else {
+		ret = -EBADSLT;
+		if (key->watchers) {
+			down_write(&key->sem);
+			ret = remove_watch_from_object(key->watchers,
+						       wqueue, key_serial(key),
+						       false);
+			up_write(&key->sem);
+		}
+	}
+
+err_watch:
+	kfree(watch);
+err_wlist:
+	kfree(wlist);
+err_wqueue:
+	put_watch_queue(wqueue);
+err_key:
+	key_put(key);
+	return ret;
+}
+#endif /* CONFIG_KEY_NOTIFICATIONS */
+
+/*
+ * Get keyrings subsystem capabilities.
+ */
+long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
+{
+	size_t size = buflen;
+
+	if (size > 0) {
+		if (size > sizeof(keyrings_capabilities))
+			size = sizeof(keyrings_capabilities);
+		if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
+			return -EFAULT;
+		if (size < buflen &&
+		    clear_user(_buffer + size, buflen - size) != 0)
+			return -EFAULT;
+	}
+
+	return sizeof(keyrings_capabilities);
+}
+
+/*
+ * The key control system call
+ */
+SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
+		unsigned long, arg4, unsigned long, arg5)
+{
+	switch (option) {
+	case KEYCTL_GET_KEYRING_ID:
+		return keyctl_get_keyring_ID((key_serial_t) arg2,
+					     (int) arg3);
+
+	case KEYCTL_JOIN_SESSION_KEYRING:
+		return keyctl_join_session_keyring((const char __user *) arg2);
+
+	case KEYCTL_UPDATE:
+		return keyctl_update_key((key_serial_t) arg2,
+					 (const void __user *) arg3,
+					 (size_t) arg4);
+
+	case KEYCTL_REVOKE:
+		return keyctl_revoke_key((key_serial_t) arg2);
+
+	case KEYCTL_DESCRIBE:
+		return keyctl_describe_key((key_serial_t) arg2,
+					   (char __user *) arg3,
+					   (unsigned) arg4);
+
+	case KEYCTL_CLEAR:
+		return keyctl_keyring_clear((key_serial_t) arg2);
+
+	case KEYCTL_LINK:
+		return keyctl_keyring_link((key_serial_t) arg2,
+					   (key_serial_t) arg3);
+
+	case KEYCTL_UNLINK:
+		return keyctl_keyring_unlink((key_serial_t) arg2,
+					     (key_serial_t) arg3);
+
+	case KEYCTL_SEARCH:
+		return keyctl_keyring_search((key_serial_t) arg2,
+					     (const char __user *) arg3,
+					     (const char __user *) arg4,
+					     (key_serial_t) arg5);
+
+	case KEYCTL_READ:
+		return keyctl_read_key((key_serial_t) arg2,
+				       (char __user *) arg3,
+				       (size_t) arg4);
+
+	case KEYCTL_CHOWN:
+		return keyctl_chown_key((key_serial_t) arg2,
+					(uid_t) arg3,
+					(gid_t) arg4);
+
+	case KEYCTL_SETPERM:
+		return keyctl_setperm_key((key_serial_t) arg2,
+					  (key_perm_t) arg3);
+
+	case KEYCTL_INSTANTIATE:
+		return keyctl_instantiate_key((key_serial_t) arg2,
+					      (const void __user *) arg3,
+					      (size_t) arg4,
+					      (key_serial_t) arg5);
+
+	case KEYCTL_NEGATE:
+		return keyctl_negate_key((key_serial_t) arg2,
+					 (unsigned) arg3,
+					 (key_serial_t) arg4);
+
+	case KEYCTL_SET_REQKEY_KEYRING:
+		return keyctl_set_reqkey_keyring(arg2);
+
+	case KEYCTL_SET_TIMEOUT:
+		return keyctl_set_timeout((key_serial_t) arg2,
+					  (unsigned) arg3);
+
+	case KEYCTL_ASSUME_AUTHORITY:
+		return keyctl_assume_authority((key_serial_t) arg2);
+
+	case KEYCTL_GET_SECURITY:
+		return keyctl_get_security((key_serial_t) arg2,
+					   (char __user *) arg3,
+					   (size_t) arg4);
+
+	case KEYCTL_SESSION_TO_PARENT:
+		return keyctl_session_to_parent();
+
+	case KEYCTL_REJECT:
+		return keyctl_reject_key((key_serial_t) arg2,
+					 (unsigned) arg3,
+					 (unsigned) arg4,
+					 (key_serial_t) arg5);
+
+	case KEYCTL_INSTANTIATE_IOV:
+		return keyctl_instantiate_key_iov(
+			(key_serial_t) arg2,
+			(const struct iovec __user *) arg3,
+			(unsigned) arg4,
+			(key_serial_t) arg5);
+
+	case KEYCTL_INVALIDATE:
+		return keyctl_invalidate_key((key_serial_t) arg2);
+
+	case KEYCTL_GET_PERSISTENT:
+		return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
+
+	case KEYCTL_DH_COMPUTE:
+		return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
+					 (char __user *) arg3, (size_t) arg4,
+					 (struct keyctl_kdf_params __user *) arg5);
+
+	case KEYCTL_RESTRICT_KEYRING:
+		return keyctl_restrict_keyring((key_serial_t) arg2,
+					       (const char __user *) arg3,
+					       (const char __user *) arg4);
+
+	case KEYCTL_PKEY_QUERY:
+		if (arg3 != 0)
+			return -EINVAL;
+		return keyctl_pkey_query((key_serial_t)arg2,
+					 (const char __user *)arg4,
+					 (struct keyctl_pkey_query __user *)arg5);
+
+	case KEYCTL_PKEY_ENCRYPT:
+	case KEYCTL_PKEY_DECRYPT:
+	case KEYCTL_PKEY_SIGN:
+		return keyctl_pkey_e_d_s(
+			option,
+			(const struct keyctl_pkey_params __user *)arg2,
+			(const char __user *)arg3,
+			(const void __user *)arg4,
+			(void __user *)arg5);
+
+	case KEYCTL_PKEY_VERIFY:
+		return keyctl_pkey_verify(
+			(const struct keyctl_pkey_params __user *)arg2,
+			(const char __user *)arg3,
+			(const void __user *)arg4,
+			(const void __user *)arg5);
+
+	case KEYCTL_MOVE:
+		return keyctl_keyring_move((key_serial_t)arg2,
+					   (key_serial_t)arg3,
+					   (key_serial_t)arg4,
+					   (unsigned int)arg5);
+
+	case KEYCTL_CAPABILITIES:
+		return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
+
+	case KEYCTL_WATCH_KEY:
+		return keyctl_watch_key((key_serial_t)arg2, (int)arg3, (int)arg4);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+}