Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

security/keys/Makefile

@@ -0,0 +1,14 @@
+#
+# Makefile for key management
+#
+
+obj-y := \
+	key.o \
+	keyring.o \
+	keyctl.o \
+	process_keys.o \
+	user_defined.o \
+	request_key.o
+
+obj-$(CONFIG_KEYS_COMPAT) += compat.o
+obj-$(CONFIG_PROC_FS) += proc.o

security/keys/compat.c

@@ -0,0 +1,78 @@
+/* compat.c: 32-bit compatibility syscall for 64-bit systems
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include <linux/syscalls.h>
+#include <linux/keyctl.h>
+#include <linux/compat.h>
+#include "internal.h"
+
+/*****************************************************************************/
+/*
+ * the key control system call, 32-bit compatibility version for 64-bit archs
+ * - this should only be called if the 64-bit arch uses weird pointers in
+ *   32-bit mode or doesn't guarantee that the top 32-bits of the argument
+ *   registers on taking a 32-bit syscall are zero
+ * - if you can, you should call sys_keyctl directly
+ */
+asmlinkage long compat_sys_keyctl(u32 option,
+			      u32 arg2, u32 arg3, u32 arg4, u32 arg5)
+{
+	switch (option) {
+	case KEYCTL_GET_KEYRING_ID:
+		return keyctl_get_keyring_ID(arg2, arg3);
+
+	case KEYCTL_JOIN_SESSION_KEYRING:
+		return keyctl_join_session_keyring(compat_ptr(arg2));
+
+	case KEYCTL_UPDATE:
+		return keyctl_update_key(arg2, compat_ptr(arg3), arg4);
+
+	case KEYCTL_REVOKE:
+		return keyctl_revoke_key(arg2);
+
+	case KEYCTL_DESCRIBE:
+		return keyctl_describe_key(arg2, compat_ptr(arg3), arg4);
+
+	case KEYCTL_CLEAR:
+		return keyctl_keyring_clear(arg2);
+
+	case KEYCTL_LINK:
+		return keyctl_keyring_link(arg2, arg3);
+
+	case KEYCTL_UNLINK:
+		return keyctl_keyring_unlink(arg2, arg3);
+
+	case KEYCTL_SEARCH:
+		return keyctl_keyring_search(arg2, compat_ptr(arg3),
+					     compat_ptr(arg4), arg5);
+
+	case KEYCTL_READ:
+		return keyctl_read_key(arg2, compat_ptr(arg3), arg4);
+
+	case KEYCTL_CHOWN:
+		return keyctl_chown_key(arg2, arg3, arg4);
+
+	case KEYCTL_SETPERM:
+		return keyctl_setperm_key(arg2, arg3);
+
+	case KEYCTL_INSTANTIATE:
+		return keyctl_instantiate_key(arg2, compat_ptr(arg3), arg4,
+					      arg5);
+
+	case KEYCTL_NEGATE:
+		return keyctl_negate_key(arg2, arg3, arg4);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+} /* end compat_sys_keyctl() */

security/keys/internal.h

@@ -0,0 +1,123 @@
+/* internal.h: authentication token and access key management internal defs
+ *
+ * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _INTERNAL_H
+#define _INTERNAL_H
+
+#include <linux/key.h>
+#include <linux/key-ui.h>
+
+extern struct key_type key_type_dead;
+extern struct key_type key_type_user;
+
+/*****************************************************************************/
+/*
+ * keep track of keys for a user
+ * - this needs to be separate to user_struct to avoid a refcount-loop
+ *   (user_struct pins some keyrings which pin this struct)
+ * - this also keeps track of keys under request from userspace for this UID
+ */
+struct key_user {
+	struct rb_node		node;
+	struct list_head	consq;		/* construction queue */
+	spinlock_t		lock;
+	atomic_t		usage;		/* for accessing qnkeys & qnbytes */
+	atomic_t		nkeys;		/* number of keys */
+	atomic_t		nikeys;		/* number of instantiated keys */
+	uid_t			uid;
+	int			qnkeys;		/* number of keys allocated to this user */
+	int			qnbytes;	/* number of bytes allocated to this user */
+};
+
+#define KEYQUOTA_MAX_KEYS	100
+#define KEYQUOTA_MAX_BYTES	10000
+#define KEYQUOTA_LINK_BYTES	4		/* a link in a keyring is worth 4 bytes */
+
+extern struct rb_root	key_user_tree;
+extern spinlock_t	key_user_lock;
+extern struct key_user	root_key_user;
+
+extern struct key_user *key_user_lookup(uid_t uid);
+extern void key_user_put(struct key_user *user);
+
+
+
+extern struct rb_root key_serial_tree;
+extern spinlock_t key_serial_lock;
+extern struct semaphore key_alloc_sem;
+extern struct rw_semaphore key_construction_sem;
+extern wait_queue_head_t request_key_conswq;
+
+
+extern void keyring_publish_name(struct key *keyring);
+
+extern int __key_link(struct key *keyring, struct key *key);
+
+extern struct key *__keyring_search_one(struct key *keyring,
+					const struct key_type *type,
+					const char *description,
+					key_perm_t perm);
+
+typedef int (*key_match_func_t)(const struct key *, const void *);
+
+extern struct key *keyring_search_aux(struct key *keyring,
+				      struct key_type *type,
+				      const void *description,
+				      key_match_func_t match);
+
+extern struct key *search_process_keyrings_aux(struct key_type *type,
+					       const void *description,
+					       key_match_func_t match);
+
+extern struct key *find_keyring_by_name(const char *name, key_serial_t bound);
+
+extern int install_thread_keyring(struct task_struct *tsk);
+
+/*
+ * keyctl functions
+ */
+extern long keyctl_get_keyring_ID(key_serial_t, int);
+extern long keyctl_join_session_keyring(const char __user *);
+extern long keyctl_update_key(key_serial_t, const void __user *, size_t);
+extern long keyctl_revoke_key(key_serial_t);
+extern long keyctl_keyring_clear(key_serial_t);
+extern long keyctl_keyring_link(key_serial_t, key_serial_t);
+extern long keyctl_keyring_unlink(key_serial_t, key_serial_t);
+extern long keyctl_describe_key(key_serial_t, char __user *, size_t);
+extern long keyctl_keyring_search(key_serial_t, const char __user *,
+				  const char __user *, key_serial_t);
+extern long keyctl_read_key(key_serial_t, char __user *, size_t);
+extern long keyctl_chown_key(key_serial_t, uid_t, gid_t);
+extern long keyctl_setperm_key(key_serial_t, key_perm_t);
+extern long keyctl_instantiate_key(key_serial_t, const void __user *,
+				   size_t, key_serial_t);
+extern long keyctl_negate_key(key_serial_t, unsigned, key_serial_t);
+
+
+/*
+ * debugging key validation
+ */
+#ifdef KEY_DEBUGGING
+extern void __key_check(const struct key *);
+
+static inline void key_check(const struct key *key)
+{
+	if (key && (IS_ERR(key) || key->magic != KEY_DEBUG_MAGIC))
+		__key_check(key);
+}
+
+#else
+
+#define key_check(key) do {} while(0)
+
+#endif
+
+#endif /* _INTERNAL_H */

security/keys/keyctl.c

@@ -0,0 +1,987 @@
+/* keyctl.c: userspace keyctl operations
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/keyctl.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/*****************************************************************************/
+/*
+ * 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
+ * - the keyring must be writable
+ * - returns the new key's serial number
+ * - implements add_key()
+ */
+asmlinkage long sys_add_key(const char __user *_type,
+			    const char __user *_description,
+			    const void __user *_payload,
+			    size_t plen,
+			    key_serial_t ringid)
+{
+	struct key *keyring, *key;
+	char type[32], *description;
+	void *payload;
+	long dlen, ret;
+
+	ret = -EINVAL;
+	if (plen > 32767)
+		goto error;
+
+	/* draw all the data into kernel space */
+	ret = strncpy_from_user(type, _type, sizeof(type) - 1);
+	if (ret < 0)
+		goto error;
+	type[31] = '\0';
+
+	ret = -EFAULT;
+	dlen = strnlen_user(_description, PAGE_SIZE - 1);
+	if (dlen <= 0)
+		goto error;
+
+	ret = -EINVAL;
+	if (dlen > PAGE_SIZE - 1)
+		goto error;
+
+	ret = -ENOMEM;
+	description = kmalloc(dlen + 1, GFP_KERNEL);
+	if (!description)
+		goto error;
+
+	ret = -EFAULT;
+	if (copy_from_user(description, _description, dlen + 1) != 0)
+		goto error2;
+
+	/* pull the payload in if one was supplied */
+	payload = NULL;
+
+	if (_payload) {
+		ret = -ENOMEM;
+		payload = kmalloc(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 = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error3;
+	}
+
+	/* create or update the requested key and add it to the target
+	 * keyring */
+	key = key_create_or_update(keyring, type, description,
+				   payload, plen, 0);
+	if (!IS_ERR(key)) {
+		ret = key->serial;
+		key_put(key);
+	}
+	else {
+		ret = PTR_ERR(key);
+	}
+
+	key_put(keyring);
+ error3:
+	kfree(payload);
+ error2:
+	kfree(description);
+ error:
+	return ret;
+
+} /* end sys_add_key() */
+
+/*****************************************************************************/
+/*
+ * search the process keyrings for a matching key
+ * - nested keyrings may also be searched if they have Search permission
+ * - if a key is found, it will be attached to the destination keyring if
+ *   there's one specified
+ * - /sbin/request-key will be invoked if _callout_info is non-NULL
+ *   - the _callout_info string will be passed to /sbin/request-key
+ *   - if the _callout_info string is empty, it will be rendered as "-"
+ * - implements request_key()
+ */
+asmlinkage long sys_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, *dest;
+	char type[32], *description, *callout_info;
+	long dlen, ret;
+
+	/* pull the type into kernel space */
+	ret = strncpy_from_user(type, _type, sizeof(type) - 1);
+	if (ret < 0)
+		goto error;
+	type[31] = '\0';
+
+	/* pull the description into kernel space */
+	ret = -EFAULT;
+	dlen = strnlen_user(_description, PAGE_SIZE - 1);
+	if (dlen <= 0)
+		goto error;
+
+	ret = -EINVAL;
+	if (dlen > PAGE_SIZE - 1)
+		goto error;
+
+	ret = -ENOMEM;
+	description = kmalloc(dlen + 1, GFP_KERNEL);
+	if (!description)
+		goto error;
+
+	ret = -EFAULT;
+	if (copy_from_user(description, _description, dlen + 1) != 0)
+		goto error2;
+
+	/* pull the callout info into kernel space */
+	callout_info = NULL;
+	if (_callout_info) {
+		ret = -EFAULT;
+		dlen = strnlen_user(_callout_info, PAGE_SIZE - 1);
+		if (dlen <= 0)
+			goto error2;
+
+		ret = -EINVAL;
+		if (dlen > PAGE_SIZE - 1)
+			goto error2;
+
+		ret = -ENOMEM;
+		callout_info = kmalloc(dlen + 1, GFP_KERNEL);
+		if (!callout_info)
+			goto error2;
+
+		ret = -EFAULT;
+		if (copy_from_user(callout_info, _callout_info, dlen + 1) != 0)
+			goto error3;
+	}
+
+	/* get the destination keyring if specified */
+	dest = NULL;
+	if (destringid) {
+		dest = lookup_user_key(destringid, 1, 0, KEY_WRITE);
+		if (IS_ERR(dest)) {
+			ret = PTR_ERR(dest);
+			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(ktype, description, callout_info);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error5;
+	}
+
+	/* link the resulting key to the destination keyring */
+	if (dest) {
+		ret = key_link(dest, key);
+		if (ret < 0)
+			goto error6;
+	}
+
+	ret = key->serial;
+
+ error6:
+	key_put(key);
+ error5:
+	key_type_put(ktype);
+ error4:
+	key_put(dest);
+ error3:
+	kfree(callout_info);
+ error2:
+	kfree(description);
+ error:
+	return ret;
+
+} /* end sys_request_key() */
+
+/*****************************************************************************/
+/*
+ * get the ID of the specified process keyring
+ * - the keyring must have search permission to be found
+ * - implements keyctl(KEYCTL_GET_KEYRING_ID)
+ */
+long keyctl_get_keyring_ID(key_serial_t id, int create)
+{
+	struct key *key;
+	long ret;
+
+	key = lookup_user_key(id, create, 0, KEY_SEARCH);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	ret = key->serial;
+	key_put(key);
+ error:
+	return ret;
+
+} /* end keyctl_get_keyring_ID() */
+
+/*****************************************************************************/
+/*
+ * join the session keyring
+ * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING)
+ */
+long keyctl_join_session_keyring(const char __user *_name)
+{
+	char *name;
+	long nlen, ret;
+
+	/* fetch the name from userspace */
+	name = NULL;
+	if (_name) {
+		ret = -EFAULT;
+		nlen = strnlen_user(_name, PAGE_SIZE - 1);
+		if (nlen <= 0)
+			goto error;
+
+		ret = -EINVAL;
+		if (nlen > PAGE_SIZE - 1)
+			goto error;
+
+		ret = -ENOMEM;
+		name = kmalloc(nlen + 1, GFP_KERNEL);
+		if (!name)
+			goto error;
+
+		ret = -EFAULT;
+		if (copy_from_user(name, _name, nlen + 1) != 0)
+			goto error2;
+	}
+
+	/* join the session */
+	ret = join_session_keyring(name);
+
+ error2:
+	kfree(name);
+ error:
+	return ret;
+
+} /* end keyctl_join_session_keyring() */
+
+/*****************************************************************************/
+/*
+ * update a key's data payload
+ * - the key must be writable
+ * - implements keyctl(KEYCTL_UPDATE)
+ */
+long keyctl_update_key(key_serial_t id,
+		       const void __user *_payload,
+		       size_t plen)
+{
+	struct key *key;
+	void *payload;
+	long ret;
+
+	ret = -EINVAL;
+	if (plen > PAGE_SIZE)
+		goto error;
+
+	/* pull the payload in if one was supplied */
+	payload = NULL;
+	if (_payload) {
+		ret = -ENOMEM;
+		payload = kmalloc(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 = lookup_user_key(id, 0, 0, KEY_WRITE);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error2;
+	}
+
+	/* update the key */
+	ret = key_update(key, payload, plen);
+
+	key_put(key);
+ error2:
+	kfree(payload);
+ error:
+	return ret;
+
+} /* end keyctl_update_key() */
+
+/*****************************************************************************/
+/*
+ * revoke a key
+ * - the key must be writable
+ * - implements keyctl(KEYCTL_REVOKE)
+ */
+long keyctl_revoke_key(key_serial_t id)
+{
+	struct key *key;
+	long ret;
+
+	key = lookup_user_key(id, 0, 0, KEY_WRITE);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	key_revoke(key);
+	ret = 0;
+
+	key_put(key);
+ error:
+	return 0;
+
+} /* end keyctl_revoke_key() */
+
+/*****************************************************************************/
+/*
+ * clear the specified process keyring
+ * - the keyring must be writable
+ * - implements keyctl(KEYCTL_CLEAR)
+ */
+long keyctl_keyring_clear(key_serial_t ringid)
+{
+	struct key *keyring;
+	long ret;
+
+	keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error;
+	}
+
+	ret = keyring_clear(keyring);
+
+	key_put(keyring);
+ error:
+	return ret;
+
+} /* end keyctl_keyring_clear() */
+
+/*****************************************************************************/
+/*
+ * link a key into a keyring
+ * - the keyring must be writable
+ * - the key must be linkable
+ * - implements keyctl(KEYCTL_LINK)
+ */
+long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
+{
+	struct key *keyring, *key;
+	long ret;
+
+	keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error;
+	}
+
+	key = lookup_user_key(id, 1, 0, KEY_LINK);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error2;
+	}
+
+	ret = key_link(keyring, key);
+
+	key_put(key);
+ error2:
+	key_put(keyring);
+ error:
+	return ret;
+
+} /* end keyctl_keyring_link() */
+
+/*****************************************************************************/
+/*
+ * unlink the first attachment of a key from a keyring
+ * - the keyring must be writable
+ * - we don't need any permissions on the key
+ * - implements keyctl(KEYCTL_UNLINK)
+ */
+long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
+{
+	struct key *keyring, *key;
+	long ret;
+
+	keyring = lookup_user_key(ringid, 0, 0, KEY_WRITE);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error;
+	}
+
+	key = lookup_user_key(id, 0, 0, 0);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error2;
+	}
+
+	ret = key_unlink(keyring, key);
+
+	key_put(key);
+ error2:
+	key_put(keyring);
+ error:
+	return ret;
+
+} /* end keyctl_keyring_unlink() */
+
+/*****************************************************************************/
+/*
+ * describe a user key
+ * - the key must have view permission
+ * - if there's a buffer, we place up to buflen bytes of data into it
+ * - unless there's an error, we return the amount of description available,
+ *   irrespective of how much we may have copied
+ * - the description is formatted thus:
+ *	type;uid;gid;perm;description<NUL>
+ * - implements keyctl(KEYCTL_DESCRIBE)
+ */
+long keyctl_describe_key(key_serial_t keyid,
+			 char __user *buffer,
+			 size_t buflen)
+{
+	struct key *key;
+	char *tmpbuf;
+	long ret;
+
+	key = lookup_user_key(keyid, 0, 1, KEY_VIEW);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	/* calculate how much description we're going to return */
+	ret = -ENOMEM;
+	tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!tmpbuf)
+		goto error2;
+
+	ret = snprintf(tmpbuf, PAGE_SIZE - 1,
+		       "%s;%d;%d;%06x;%s",
+		       key->type->name,
+		       key->uid,
+		       key->gid,
+		       key->perm,
+		       key->description ? key->description :""
+		       );
+
+	/* include a NUL char at the end of the data */
+	if (ret > PAGE_SIZE - 1)
+		ret = PAGE_SIZE - 1;
+	tmpbuf[ret] = 0;
+	ret++;
+
+	/* consider returning the data */
+	if (buffer && buflen > 0) {
+		if (buflen > ret)
+			buflen = ret;
+
+		if (copy_to_user(buffer, tmpbuf, buflen) != 0)
+			ret = -EFAULT;
+	}
+
+	kfree(tmpbuf);
+ error2:
+	key_put(key);
+ error:
+	return ret;
+
+} /* end keyctl_describe_key() */
+
+/*****************************************************************************/
+/*
+ * search the specified keyring for a matching key
+ * - the start keyring must be searchable
+ * - nested keyrings may also be searched if they are searchable
+ * - only keys with search permission may be found
+ * - if a key is found, it will be attached to the destination keyring if
+ *   there's one specified
+ * - implements keyctl(KEYCTL_SEARCH)
+ */
+long keyctl_keyring_search(key_serial_t ringid,
+			   const char __user *_type,
+			   const char __user *_description,
+			   key_serial_t destringid)
+{
+	struct key_type *ktype;
+	struct key *keyring, *key, *dest;
+	char type[32], *description;
+	long dlen, ret;
+
+	/* pull the type and description into kernel space */
+	ret = strncpy_from_user(type, _type, sizeof(type) - 1);
+	if (ret < 0)
+		goto error;
+	type[31] = '\0';
+
+	ret = -EFAULT;
+	dlen = strnlen_user(_description, PAGE_SIZE - 1);
+	if (dlen <= 0)
+		goto error;
+
+	ret = -EINVAL;
+	if (dlen > PAGE_SIZE - 1)
+		goto error;
+
+	ret = -ENOMEM;
+	description = kmalloc(dlen + 1, GFP_KERNEL);
+	if (!description)
+		goto error;
+
+	ret = -EFAULT;
+	if (copy_from_user(description, _description, dlen + 1) != 0)
+		goto error2;
+
+	/* get the keyring at which to begin the search */
+	keyring = lookup_user_key(ringid, 0, 0, KEY_SEARCH);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error2;
+	}
+
+	/* get the destination keyring if specified */
+	dest = NULL;
+	if (destringid) {
+		dest = lookup_user_key(destringid, 1, 0, KEY_WRITE);
+		if (IS_ERR(dest)) {
+			ret = PTR_ERR(dest);
+			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 = keyring_search(keyring, ktype, description);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+
+		/* 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) {
+		ret = -EACCES;
+		if (!key_permission(key, KEY_LINK))
+			goto error6;
+
+		ret = key_link(dest, key);
+		if (ret < 0)
+			goto error6;
+	}
+
+	ret = key->serial;
+
+ error6:
+	key_put(key);
+ error5:
+	key_type_put(ktype);
+ error4:
+	key_put(dest);
+ error3:
+	key_put(keyring);
+ error2:
+	kfree(description);
+ error:
+	return ret;
+
+} /* end keyctl_keyring_search() */
+
+/*****************************************************************************/
+/*
+ * see if the key we're looking at is the target key
+ */
+static int keyctl_read_key_same(const struct key *key, const void *target)
+{
+	return key == target;
+
+} /* end keyctl_read_key_same() */
+
+/*****************************************************************************/
+/*
+ * read a user key's payload
+ * - the keyring must be readable or the key must be searchable from the
+ *   process's keyrings
+ * - if there's a buffer, we place up to buflen bytes of data into it
+ * - unless there's an error, we return the amount of data in the key,
+ *   irrespective of how much we may have copied
+ * - implements keyctl(KEYCTL_READ)
+ */
+long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
+{
+	struct key *key, *skey;
+	long ret;
+
+	/* find the key first */
+	key = lookup_user_key(keyid, 0, 0, 0);
+	if (!IS_ERR(key)) {
+		/* see if we can read it directly */
+		if (key_permission(key, KEY_READ))
+			goto can_read_key;
+
+		/* can't; see if it's searchable from this process's
+		 * keyrings */
+		ret = -ENOKEY;
+		if (key_permission(key, KEY_SEARCH)) {
+			/* okay - we do have search permission on the key
+			 * itself, but do we have the key? */
+			skey = search_process_keyrings_aux(key->type, key,
+							   keyctl_read_key_same);
+			if (!IS_ERR(skey))
+				goto can_read_key2;
+		}
+
+		goto error2;
+	}
+
+	ret = -ENOKEY;
+	goto error;
+
+	/* the key is probably readable - now try to read it */
+ can_read_key2:
+	key_put(skey);
+ can_read_key:
+	ret = key_validate(key);
+	if (ret == 0) {
+		ret = -EOPNOTSUPP;
+		if (key->type->read) {
+			/* read the data with the semaphore held (since we
+			 * might sleep) */
+			down_read(&key->sem);
+			ret = key->type->read(key, buffer, buflen);
+			up_read(&key->sem);
+		}
+	}
+
+ error2:
+	key_put(key);
+ error:
+	return ret;
+
+} /* end keyctl_read_key() */
+
+/*****************************************************************************/
+/*
+ * change the ownership of a key
+ * - the keyring owned by the changer
+ * - if the uid or gid is -1, then that parameter is not changed
+ * - implements keyctl(KEYCTL_CHOWN)
+ */
+long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
+{
+	struct key *key;
+	long ret;
+
+	ret = 0;
+	if (uid == (uid_t) -1 && gid == (gid_t) -1)
+		goto error;
+
+	key = lookup_user_key(id, 1, 1, 0);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	/* make the changes with the locks held to prevent chown/chown races */
+	ret = -EACCES;
+	down_write(&key->sem);
+	write_lock(&key->lock);
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		/* only the sysadmin can chown a key to some other UID */
+		if (uid != (uid_t) -1 && key->uid != uid)
+			goto no_access;
+
+		/* only the sysadmin can set the key's GID to a group other
+		 * than one of those that the current process subscribes to */
+		if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
+			goto no_access;
+	}
+
+	/* change the UID (have to update the quotas) */
+	if (uid != (uid_t) -1 && uid != key->uid) {
+		/* don't support UID changing yet */
+		ret = -EOPNOTSUPP;
+		goto no_access;
+	}
+
+	/* change the GID */
+	if (gid != (gid_t) -1)
+		key->gid = gid;
+
+	ret = 0;
+
+ no_access:
+	write_unlock(&key->lock);
+	up_write(&key->sem);
+	key_put(key);
+ error:
+	return ret;
+
+} /* end keyctl_chown_key() */
+
+/*****************************************************************************/
+/*
+ * change the permission mask on a key
+ * - the keyring owned by the changer
+ * - implements keyctl(KEYCTL_SETPERM)
+ */
+long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
+{
+	struct key *key;
+	long ret;
+
+	ret = -EINVAL;
+	if (perm & ~(KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
+		goto error;
+
+	key = lookup_user_key(id, 1, 1, 0);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	/* make the changes with the locks held to prevent chown/chmod
+	 * races */
+	ret = -EACCES;
+	down_write(&key->sem);
+	write_lock(&key->lock);
+
+	/* if we're not the sysadmin, we can only chmod a key that we
+	 * own */
+	if (!capable(CAP_SYS_ADMIN) && key->uid != current->fsuid)
+		goto no_access;
+
+	/* changing the permissions mask */
+	key->perm = perm;
+	ret = 0;
+
+ no_access:
+	write_unlock(&key->lock);
+	up_write(&key->sem);
+	key_put(key);
+ error:
+	return ret;
+
+} /* end keyctl_setperm_key() */
+
+/*****************************************************************************/
+/*
+ * instantiate the key with the specified payload, and, if one is given, link
+ * the key into the keyring
+ */
+long keyctl_instantiate_key(key_serial_t id,
+			    const void __user *_payload,
+			    size_t plen,
+			    key_serial_t ringid)
+{
+	struct key *key, *keyring;
+	void *payload;
+	long ret;
+
+	ret = -EINVAL;
+	if (plen > 32767)
+		goto error;
+
+	/* pull the payload in if one was supplied */
+	payload = NULL;
+
+	if (_payload) {
+		ret = -ENOMEM;
+		payload = kmalloc(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 = lookup_user_key(id, 0, 1, KEY_WRITE);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error2;
+	}
+
+	/* find the destination keyring if present (which must also be
+	 * writable) */
+	keyring = NULL;
+	if (ringid) {
+		keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+		if (IS_ERR(keyring)) {
+			ret = PTR_ERR(keyring);
+			goto error3;
+		}
+	}
+
+	/* instantiate the key and link it into a keyring */
+	ret = key_instantiate_and_link(key, payload, plen, keyring);
+
+	key_put(keyring);
+ error3:
+	key_put(key);
+ error2:
+	kfree(payload);
+ error:
+	return ret;
+
+} /* end keyctl_instantiate_key() */
+
+/*****************************************************************************/
+/*
+ * negatively instantiate the key with the given timeout (in seconds), and, if
+ * one is given, link the key into the keyring
+ */
+long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
+{
+	struct key *key, *keyring;
+	long ret;
+
+	/* find the target key (which must be writable) */
+	key = lookup_user_key(id, 0, 1, KEY_WRITE);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto error;
+	}
+
+	/* find the destination keyring if present (which must also be
+	 * writable) */
+	keyring = NULL;
+	if (ringid) {
+		keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+		if (IS_ERR(keyring)) {
+			ret = PTR_ERR(keyring);
+			goto error2;
+		}
+	}
+
+	/* instantiate the key and link it into a keyring */
+	ret = key_negate_and_link(key, timeout, keyring);
+
+	key_put(keyring);
+ error2:
+	key_put(key);
+ error:
+	return ret;
+
+} /* end keyctl_negate_key() */
+
+/*****************************************************************************/
+/*
+ * the key control system call
+ */
+asmlinkage long sys_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);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+} /* end sys_keyctl() */

security/keys/keyring.c

@@ -0,0 +1,895 @@
+/* keyring.c: keyring handling
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/*
+ * when plumbing the depths of the key tree, this sets a hard limit set on how
+ * deep we're willing to go
+ */
+#define KEYRING_SEARCH_MAX_DEPTH 6
+
+/*
+ * we keep all named keyrings in a hash to speed looking them up
+ */
+#define KEYRING_NAME_HASH_SIZE	(1 << 5)
+
+static struct list_head	keyring_name_hash[KEYRING_NAME_HASH_SIZE];
+static DEFINE_RWLOCK(keyring_name_lock);
+
+static inline unsigned keyring_hash(const char *desc)
+{
+	unsigned bucket = 0;
+
+	for (; *desc; desc++)
+		bucket += (unsigned char) *desc;
+
+	return bucket & (KEYRING_NAME_HASH_SIZE - 1);
+}
+
+/*
+ * the keyring type definition
+ */
+static int keyring_instantiate(struct key *keyring,
+			       const void *data, size_t datalen);
+static int keyring_duplicate(struct key *keyring, const struct key *source);
+static int keyring_match(const struct key *keyring, const void *criterion);
+static void keyring_destroy(struct key *keyring);
+static void keyring_describe(const struct key *keyring, struct seq_file *m);
+static long keyring_read(const struct key *keyring,
+			 char __user *buffer, size_t buflen);
+
+struct key_type key_type_keyring = {
+	.name		= "keyring",
+	.def_datalen	= sizeof(struct keyring_list),
+	.instantiate	= keyring_instantiate,
+	.duplicate	= keyring_duplicate,
+	.match		= keyring_match,
+	.destroy	= keyring_destroy,
+	.describe	= keyring_describe,
+	.read		= keyring_read,
+};
+
+/*
+ * semaphore to serialise link/link calls to prevent two link calls in parallel
+ * introducing a cycle
+ */
+DECLARE_RWSEM(keyring_serialise_link_sem);
+
+/*****************************************************************************/
+/*
+ * publish the name of a keyring so that it can be found by name (if it has
+ * one)
+ */
+void keyring_publish_name(struct key *keyring)
+{
+	int bucket;
+
+	if (keyring->description) {
+		bucket = keyring_hash(keyring->description);
+
+		write_lock(&keyring_name_lock);
+
+		if (!keyring_name_hash[bucket].next)
+			INIT_LIST_HEAD(&keyring_name_hash[bucket]);
+
+		list_add_tail(&keyring->type_data.link,
+			      &keyring_name_hash[bucket]);
+
+		write_unlock(&keyring_name_lock);
+	}
+
+} /* end keyring_publish_name() */
+
+/*****************************************************************************/
+/*
+ * initialise a keyring
+ * - we object if we were given any data
+ */
+static int keyring_instantiate(struct key *keyring,
+			       const void *data, size_t datalen)
+{
+	int ret;
+
+	ret = -EINVAL;
+	if (datalen == 0) {
+		/* make the keyring available by name if it has one */
+		keyring_publish_name(keyring);
+		ret = 0;
+	}
+
+	return ret;
+
+} /* end keyring_instantiate() */
+
+/*****************************************************************************/
+/*
+ * duplicate the list of subscribed keys from a source keyring into this one
+ */
+static int keyring_duplicate(struct key *keyring, const struct key *source)
+{
+	struct keyring_list *sklist, *klist;
+	unsigned max;
+	size_t size;
+	int loop, ret;
+
+	const unsigned limit =
+		(PAGE_SIZE - sizeof(*klist)) / sizeof(struct key);
+
+	ret = 0;
+	sklist = source->payload.subscriptions;
+
+	if (sklist && sklist->nkeys > 0) {
+		max = sklist->nkeys;
+		BUG_ON(max > limit);
+
+		max = (max + 3) & ~3;
+		if (max > limit)
+			max = limit;
+
+		ret = -ENOMEM;
+		size = sizeof(*klist) + sizeof(struct key) * max;
+		klist = kmalloc(size, GFP_KERNEL);
+		if (!klist)
+			goto error;
+
+		klist->maxkeys = max;
+		klist->nkeys = sklist->nkeys;
+		memcpy(klist->keys,
+		       sklist->keys,
+		       sklist->nkeys * sizeof(struct key));
+
+		for (loop = klist->nkeys - 1; loop >= 0; loop--)
+			atomic_inc(&klist->keys[loop]->usage);
+
+		keyring->payload.subscriptions = klist;
+		ret = 0;
+	}
+
+ error:
+	return ret;
+
+} /* end keyring_duplicate() */
+
+/*****************************************************************************/
+/*
+ * match keyrings on their name
+ */
+static int keyring_match(const struct key *keyring, const void *description)
+{
+	return keyring->description &&
+		strcmp(keyring->description, description) == 0;
+
+} /* end keyring_match() */
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a keyring
+ */
+static void keyring_destroy(struct key *keyring)
+{
+	struct keyring_list *klist;
+	int loop;
+
+	if (keyring->description) {
+		write_lock(&keyring_name_lock);
+		list_del(&keyring->type_data.link);
+		write_unlock(&keyring_name_lock);
+	}
+
+	klist = keyring->payload.subscriptions;
+	if (klist) {
+		for (loop = klist->nkeys - 1; loop >= 0; loop--)
+			key_put(klist->keys[loop]);
+		kfree(klist);
+	}
+
+} /* end keyring_destroy() */
+
+/*****************************************************************************/
+/*
+ * describe the keyring
+ */
+static void keyring_describe(const struct key *keyring, struct seq_file *m)
+{
+	struct keyring_list *klist;
+
+	if (keyring->description) {
+		seq_puts(m, keyring->description);
+	}
+	else {
+		seq_puts(m, "[anon]");
+	}
+
+	klist = keyring->payload.subscriptions;
+	if (klist)
+		seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys);
+	else
+		seq_puts(m, ": empty");
+
+} /* end keyring_describe() */
+
+/*****************************************************************************/
+/*
+ * read a list of key IDs from the keyring's contents
+ */
+static long keyring_read(const struct key *keyring,
+			 char __user *buffer, size_t buflen)
+{
+	struct keyring_list *klist;
+	struct key *key;
+	size_t qty, tmp;
+	int loop, ret;
+
+	ret = 0;
+	klist = keyring->payload.subscriptions;
+
+	if (klist) {
+		/* calculate how much data we could return */
+		qty = klist->nkeys * sizeof(key_serial_t);
+
+		if (buffer && buflen > 0) {
+			if (buflen > qty)
+				buflen = qty;
+
+			/* copy the IDs of the subscribed keys into the
+			 * buffer */
+			ret = -EFAULT;
+
+			for (loop = 0; loop < klist->nkeys; loop++) {
+				key = klist->keys[loop];
+
+				tmp = sizeof(key_serial_t);
+				if (tmp > buflen)
+					tmp = buflen;
+
+				if (copy_to_user(buffer,
+						 &key->serial,
+						 tmp) != 0)
+					goto error;
+
+				buflen -= tmp;
+				if (buflen == 0)
+					break;
+				buffer += tmp;
+			}
+		}
+
+		ret = qty;
+	}
+
+ error:
+	return ret;
+
+} /* end keyring_read() */
+
+/*****************************************************************************/
+/*
+ * allocate a keyring and link into the destination keyring
+ */
+struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
+			  int not_in_quota, struct key *dest)
+{
+	struct key *keyring;
+	int ret;
+
+	keyring = key_alloc(&key_type_keyring, description,
+			    uid, gid, KEY_USR_ALL, not_in_quota);
+
+	if (!IS_ERR(keyring)) {
+		ret = key_instantiate_and_link(keyring, NULL, 0, dest);
+		if (ret < 0) {
+			key_put(keyring);
+			keyring = ERR_PTR(ret);
+		}
+	}
+
+	return keyring;
+
+} /* end keyring_alloc() */
+
+/*****************************************************************************/
+/*
+ * search the supplied keyring tree for a key that matches the criterion
+ * - perform a breadth-then-depth search up to the prescribed limit
+ * - we only find keys on which we have search permission
+ * - we use the supplied match function to see if the description (or other
+ *   feature of interest) matches
+ * - we readlock the keyrings as we search down the tree
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we only found negative matching keys
+ */
+struct key *keyring_search_aux(struct key *keyring,
+			       struct key_type *type,
+			       const void *description,
+			       key_match_func_t match)
+{
+	struct {
+		struct key *keyring;
+		int kix;
+	} stack[KEYRING_SEARCH_MAX_DEPTH];
+
+	struct keyring_list *keylist;
+	struct timespec now;
+	struct key *key;
+	long err;
+	int sp, psp, kix;
+
+	key_check(keyring);
+
+	/* top keyring must have search permission to begin the search */
+	key = ERR_PTR(-EACCES);
+	if (!key_permission(keyring, KEY_SEARCH))
+		goto error;
+
+	key = ERR_PTR(-ENOTDIR);
+	if (keyring->type != &key_type_keyring)
+		goto error;
+
+	now = current_kernel_time();
+	err = -EAGAIN;
+	sp = 0;
+
+	/* start processing a new keyring */
+ descend:
+	read_lock(&keyring->lock);
+	if (keyring->flags & KEY_FLAG_REVOKED)
+		goto not_this_keyring;
+
+	keylist = keyring->payload.subscriptions;
+	if (!keylist)
+		goto not_this_keyring;
+
+	/* iterate through the keys in this keyring first */
+	for (kix = 0; kix < keylist->nkeys; kix++) {
+		key = keylist->keys[kix];
+
+		/* ignore keys not of this type */
+		if (key->type != type)
+			continue;
+
+		/* skip revoked keys and expired keys */
+		if (key->flags & KEY_FLAG_REVOKED)
+			continue;
+
+		if (key->expiry && now.tv_sec >= key->expiry)
+			continue;
+
+		/* keys that don't match */
+		if (!match(key, description))
+			continue;
+
+		/* key must have search permissions */
+		if (!key_permission(key, KEY_SEARCH))
+			continue;
+
+		/* we set a different error code if we find a negative key */
+		if (key->flags & KEY_FLAG_NEGATIVE) {
+			err = -ENOKEY;
+			continue;
+		}
+
+		goto found;
+	}
+
+	/* search through the keyrings nested in this one */
+	kix = 0;
+ ascend:
+	while (kix < keylist->nkeys) {
+		key = keylist->keys[kix];
+		if (key->type != &key_type_keyring)
+			goto next;
+
+		/* recursively search nested keyrings
+		 * - only search keyrings for which we have search permission
+		 */
+		if (sp >= KEYRING_SEARCH_MAX_DEPTH)
+			goto next;
+
+		if (!key_permission(key, KEY_SEARCH))
+			goto next;
+
+		/* evade loops in the keyring tree */
+		for (psp = 0; psp < sp; psp++)
+			if (stack[psp].keyring == keyring)
+				goto next;
+
+		/* stack the current position */
+		stack[sp].keyring = keyring;
+		stack[sp].kix = kix;
+		sp++;
+
+		/* begin again with the new keyring */
+		keyring = key;
+		goto descend;
+
+	next:
+		kix++;
+	}
+
+	/* the keyring we're looking at was disqualified or didn't contain a
+	 * matching key */
+ not_this_keyring:
+	read_unlock(&keyring->lock);
+
+	if (sp > 0) {
+		/* resume the processing of a keyring higher up in the tree */
+		sp--;
+		keyring = stack[sp].keyring;
+		keylist = keyring->payload.subscriptions;
+		kix = stack[sp].kix + 1;
+		goto ascend;
+	}
+
+	key = ERR_PTR(err);
+	goto error;
+
+	/* we found a viable match */
+ found:
+	atomic_inc(&key->usage);
+	read_unlock(&keyring->lock);
+
+	/* unwind the keyring stack */
+	while (sp > 0) {
+		sp--;
+		read_unlock(&stack[sp].keyring->lock);
+	}
+
+	key_check(key);
+ error:
+	return key;
+
+} /* end keyring_search_aux() */
+
+/*****************************************************************************/
+/*
+ * search the supplied keyring tree for a key that matches the criterion
+ * - perform a breadth-then-depth search up to the prescribed limit
+ * - we only find keys on which we have search permission
+ * - we readlock the keyrings as we search down the tree
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we only found negative matching keys
+ */
+struct key *keyring_search(struct key *keyring,
+			   struct key_type *type,
+			   const char *description)
+{
+	return keyring_search_aux(keyring, type, description, type->match);
+
+} /* end keyring_search() */
+
+EXPORT_SYMBOL(keyring_search);
+
+/*****************************************************************************/
+/*
+ * search the given keyring only (no recursion)
+ * - keyring must be locked by caller
+ */
+struct key *__keyring_search_one(struct key *keyring,
+				 const struct key_type *ktype,
+				 const char *description,
+				 key_perm_t perm)
+{
+	struct keyring_list *klist;
+	struct key *key;
+	int loop;
+
+	klist = keyring->payload.subscriptions;
+	if (klist) {
+		for (loop = 0; loop < klist->nkeys; loop++) {
+			key = klist->keys[loop];
+
+			if (key->type == ktype &&
+			    key->type->match(key, description) &&
+			    key_permission(key, perm) &&
+			    !(key->flags & KEY_FLAG_REVOKED)
+			    )
+				goto found;
+		}
+	}
+
+	key = ERR_PTR(-ENOKEY);
+	goto error;
+
+ found:
+	atomic_inc(&key->usage);
+ error:
+	return key;
+
+} /* end __keyring_search_one() */
+
+/*****************************************************************************/
+/*
+ * find a keyring with the specified name
+ * - all named keyrings are searched
+ * - only find keyrings with search permission for the process
+ * - only find keyrings with a serial number greater than the one specified
+ */
+struct key *find_keyring_by_name(const char *name, key_serial_t bound)
+{
+	struct key *keyring;
+	int bucket;
+
+	keyring = ERR_PTR(-EINVAL);
+	if (!name)
+		goto error;
+
+	bucket = keyring_hash(name);
+
+	read_lock(&keyring_name_lock);
+
+	if (keyring_name_hash[bucket].next) {
+		/* search this hash bucket for a keyring with a matching name
+		 * that's readable and that hasn't been revoked */
+		list_for_each_entry(keyring,
+				    &keyring_name_hash[bucket],
+				    type_data.link
+				    ) {
+			if (keyring->flags & KEY_FLAG_REVOKED)
+				continue;
+
+			if (strcmp(keyring->description, name) != 0)
+				continue;
+
+			if (!key_permission(keyring, KEY_SEARCH))
+				continue;
+
+			/* found a potential candidate, but we still need to
+			 * check the serial number */
+			if (keyring->serial <= bound)
+				continue;
+
+			/* we've got a match */
+			atomic_inc(&keyring->usage);
+			read_unlock(&keyring_name_lock);
+			goto error;
+		}
+	}
+
+	read_unlock(&keyring_name_lock);
+	keyring = ERR_PTR(-ENOKEY);
+
+ error:
+	return keyring;
+
+} /* end find_keyring_by_name() */
+
+/*****************************************************************************/
+/*
+ * see if a cycle will will be created by inserting acyclic tree B in acyclic
+ * tree A at the topmost level (ie: as a direct child of A)
+ * - since we are adding B to A at the top level, checking for cycles should
+ *   just be a matter of seeing if node A is somewhere in tree B
+ */
+static int keyring_detect_cycle(struct key *A, struct key *B)
+{
+	struct {
+		struct key *subtree;
+		int kix;
+	} stack[KEYRING_SEARCH_MAX_DEPTH];
+
+	struct keyring_list *keylist;
+	struct key *subtree, *key;
+	int sp, kix, ret;
+
+	ret = -EDEADLK;
+	if (A == B)
+		goto error;
+
+	subtree = B;
+	sp = 0;
+
+	/* start processing a new keyring */
+ descend:
+	read_lock(&subtree->lock);
+	if (subtree->flags & KEY_FLAG_REVOKED)
+		goto not_this_keyring;
+
+	keylist = subtree->payload.subscriptions;
+	if (!keylist)
+		goto not_this_keyring;
+	kix = 0;
+
+ ascend:
+	/* iterate through the remaining keys in this keyring */
+	for (; kix < keylist->nkeys; kix++) {
+		key = keylist->keys[kix];
+
+		if (key == A)
+			goto cycle_detected;
+
+		/* recursively check nested keyrings */
+		if (key->type == &key_type_keyring) {
+			if (sp >= KEYRING_SEARCH_MAX_DEPTH)
+				goto too_deep;
+
+			/* stack the current position */
+			stack[sp].subtree = subtree;
+			stack[sp].kix = kix;
+			sp++;
+
+			/* begin again with the new keyring */
+			subtree = key;
+			goto descend;
+		}
+	}
+
+	/* the keyring we're looking at was disqualified or didn't contain a
+	 * matching key */
+ not_this_keyring:
+	read_unlock(&subtree->lock);
+
+	if (sp > 0) {
+		/* resume the checking of a keyring higher up in the tree */
+		sp--;
+		subtree = stack[sp].subtree;
+		keylist = subtree->payload.subscriptions;
+		kix = stack[sp].kix + 1;
+		goto ascend;
+	}
+
+	ret = 0; /* no cycles detected */
+
+ error:
+	return ret;
+
+ too_deep:
+	ret = -ELOOP;
+	goto error_unwind;
+ cycle_detected:
+	ret = -EDEADLK;
+ error_unwind:
+	read_unlock(&subtree->lock);
+
+	/* unwind the keyring stack */
+	while (sp > 0) {
+		sp--;
+		read_unlock(&stack[sp].subtree->lock);
+	}
+
+	goto error;
+
+} /* end keyring_detect_cycle() */
+
+/*****************************************************************************/
+/*
+ * link a key into to a keyring
+ * - must be called with the keyring's semaphore held
+ */
+int __key_link(struct key *keyring, struct key *key)
+{
+	struct keyring_list *klist, *nklist;
+	unsigned max;
+	size_t size;
+	int ret;
+
+	ret = -EKEYREVOKED;
+	if (keyring->flags & KEY_FLAG_REVOKED)
+		goto error;
+
+	ret = -ENOTDIR;
+	if (keyring->type != &key_type_keyring)
+		goto error;
+
+	/* serialise link/link calls to prevent parallel calls causing a
+	 * cycle when applied to two keyring in opposite orders */
+	down_write(&keyring_serialise_link_sem);
+
+	/* check that we aren't going to create a cycle adding one keyring to
+	 * another */
+	if (key->type == &key_type_keyring) {
+		ret = keyring_detect_cycle(keyring, key);
+		if (ret < 0)
+			goto error2;
+	}
+
+	/* check that we aren't going to overrun the user's quota */
+	ret = key_payload_reserve(keyring,
+				  keyring->datalen + KEYQUOTA_LINK_BYTES);
+	if (ret < 0)
+		goto error2;
+
+	klist = keyring->payload.subscriptions;
+
+	if (klist && klist->nkeys < klist->maxkeys) {
+		/* there's sufficient slack space to add directly */
+		atomic_inc(&key->usage);
+
+		write_lock(&keyring->lock);
+		klist->keys[klist->nkeys++] = key;
+		write_unlock(&keyring->lock);
+
+		ret = 0;
+	}
+	else {
+		/* grow the key list */
+		max = 4;
+		if (klist)
+			max += klist->maxkeys;
+
+		ret = -ENFILE;
+		size = sizeof(*klist) + sizeof(*key) * max;
+		if (size > PAGE_SIZE)
+			goto error3;
+
+		ret = -ENOMEM;
+		nklist = kmalloc(size, GFP_KERNEL);
+		if (!nklist)
+			goto error3;
+		nklist->maxkeys = max;
+		nklist->nkeys = 0;
+
+		if (klist) {
+			nklist->nkeys = klist->nkeys;
+			memcpy(nklist->keys,
+			       klist->keys,
+			       sizeof(struct key *) * klist->nkeys);
+		}
+
+		/* add the key into the new space */
+		atomic_inc(&key->usage);
+
+		write_lock(&keyring->lock);
+		keyring->payload.subscriptions = nklist;
+		nklist->keys[nklist->nkeys++] = key;
+		write_unlock(&keyring->lock);
+
+		/* dispose of the old keyring list */
+		kfree(klist);
+
+		ret = 0;
+	}
+
+ error2:
+	up_write(&keyring_serialise_link_sem);
+ error:
+	return ret;
+
+ error3:
+	/* undo the quota changes */
+	key_payload_reserve(keyring,
+			    keyring->datalen - KEYQUOTA_LINK_BYTES);
+	goto error2;
+
+} /* end __key_link() */
+
+/*****************************************************************************/
+/*
+ * link a key to a keyring
+ */
+int key_link(struct key *keyring, struct key *key)
+{
+	int ret;
+
+	key_check(keyring);
+	key_check(key);
+
+	down_write(&keyring->sem);
+	ret = __key_link(keyring, key);
+	up_write(&keyring->sem);
+
+	return ret;
+
+} /* end key_link() */
+
+EXPORT_SYMBOL(key_link);
+
+/*****************************************************************************/
+/*
+ * unlink the first link to a key from a keyring
+ */
+int key_unlink(struct key *keyring, struct key *key)
+{
+	struct keyring_list *klist;
+	int loop, ret;
+
+	key_check(keyring);
+	key_check(key);
+
+	ret = -ENOTDIR;
+	if (keyring->type != &key_type_keyring)
+		goto error;
+
+	down_write(&keyring->sem);
+
+	klist = keyring->payload.subscriptions;
+	if (klist) {
+		/* search the keyring for the key */
+		for (loop = 0; loop < klist->nkeys; loop++)
+			if (klist->keys[loop] == key)
+				goto key_is_present;
+	}
+
+	up_write(&keyring->sem);
+	ret = -ENOENT;
+	goto error;
+
+ key_is_present:
+	/* adjust the user's quota */
+	key_payload_reserve(keyring,
+			    keyring->datalen - KEYQUOTA_LINK_BYTES);
+
+	/* shuffle down the key pointers
+	 * - it might be worth shrinking the allocated memory, but that runs
+	 *   the risk of ENOMEM as we would have to copy
+	 */
+	write_lock(&keyring->lock);
+
+	klist->nkeys--;
+	if (loop < klist->nkeys)
+		memcpy(&klist->keys[loop],
+		       &klist->keys[loop + 1],
+		       (klist->nkeys - loop) * sizeof(struct key *));
+
+	write_unlock(&keyring->lock);
+
+	up_write(&keyring->sem);
+	key_put(key);
+	ret = 0;
+
+ error:
+	return ret;
+
+} /* end key_unlink() */
+
+EXPORT_SYMBOL(key_unlink);
+
+/*****************************************************************************/
+/*
+ * clear the specified process keyring
+ * - implements keyctl(KEYCTL_CLEAR)
+ */
+int keyring_clear(struct key *keyring)
+{
+	struct keyring_list *klist;
+	int loop, ret;
+
+	ret = -ENOTDIR;
+	if (keyring->type == &key_type_keyring) {
+		/* detach the pointer block with the locks held */
+		down_write(&keyring->sem);
+
+		klist = keyring->payload.subscriptions;
+		if (klist) {
+			/* adjust the quota */
+			key_payload_reserve(keyring,
+					    sizeof(struct keyring_list));
+
+			write_lock(&keyring->lock);
+			keyring->payload.subscriptions = NULL;
+			write_unlock(&keyring->lock);
+		}
+
+		up_write(&keyring->sem);
+
+		/* free the keys after the locks have been dropped */
+		if (klist) {
+			for (loop = klist->nkeys - 1; loop >= 0; loop--)
+				key_put(klist->keys[loop]);
+
+			kfree(klist);
+		}
+
+		ret = 0;
+	}
+
+	return ret;
+
+} /* end keyring_clear() */
+
+EXPORT_SYMBOL(keyring_clear);

security/keys/proc.c

@@ -0,0 +1,251 @@
+/* proc.c: proc files for key database enumeration
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <asm/errno.h>
+#include "internal.h"
+
+#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
+static int proc_keys_open(struct inode *inode, struct file *file);
+static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
+static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
+static void proc_keys_stop(struct seq_file *p, void *v);
+static int proc_keys_show(struct seq_file *m, void *v);
+
+static struct seq_operations proc_keys_ops = {
+	.start	= proc_keys_start,
+	.next	= proc_keys_next,
+	.stop	= proc_keys_stop,
+	.show	= proc_keys_show,
+};
+
+static struct file_operations proc_keys_fops = {
+	.open		= proc_keys_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+#endif
+
+static int proc_key_users_open(struct inode *inode, struct file *file);
+static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
+static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
+static void proc_key_users_stop(struct seq_file *p, void *v);
+static int proc_key_users_show(struct seq_file *m, void *v);
+
+static struct seq_operations proc_key_users_ops = {
+	.start	= proc_key_users_start,
+	.next	= proc_key_users_next,
+	.stop	= proc_key_users_stop,
+	.show	= proc_key_users_show,
+};
+
+static struct file_operations proc_key_users_fops = {
+	.open		= proc_key_users_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+/*****************************************************************************/
+/*
+ * declare the /proc files
+ */
+static int __init key_proc_init(void)
+{
+	struct proc_dir_entry *p;
+
+#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
+	p = create_proc_entry("keys", 0, NULL);
+	if (!p)
+		panic("Cannot create /proc/keys\n");
+
+	p->proc_fops = &proc_keys_fops;
+#endif
+
+	p = create_proc_entry("key-users", 0, NULL);
+	if (!p)
+		panic("Cannot create /proc/key-users\n");
+
+	p->proc_fops = &proc_key_users_fops;
+
+	return 0;
+
+} /* end key_proc_init() */
+
+__initcall(key_proc_init);
+
+/*****************************************************************************/
+/*
+ * implement "/proc/keys" to provides a list of the keys on the system
+ */
+#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
+
+static int proc_keys_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &proc_keys_ops);
+
+}
+
+static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
+{
+	struct rb_node *_p;
+	loff_t pos = *_pos;
+
+	spin_lock(&key_serial_lock);
+
+	_p = rb_first(&key_serial_tree);
+	while (pos > 0 && _p) {
+		pos--;
+		_p = rb_next(_p);
+	}
+
+	return _p;
+
+}
+
+static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
+{
+	(*_pos)++;
+	return rb_next((struct rb_node *) v);
+
+}
+
+static void proc_keys_stop(struct seq_file *p, void *v)
+{
+	spin_unlock(&key_serial_lock);
+}
+
+static int proc_keys_show(struct seq_file *m, void *v)
+{
+	struct rb_node *_p = v;
+	struct key *key = rb_entry(_p, struct key, serial_node);
+	struct timespec now;
+	unsigned long timo;
+	char xbuf[12];
+
+	now = current_kernel_time();
+
+	read_lock(&key->lock);
+
+	/* come up with a suitable timeout value */
+	if (key->expiry == 0) {
+		memcpy(xbuf, "perm", 5);
+	}
+	else if (now.tv_sec >= key->expiry) {
+		memcpy(xbuf, "expd", 5);
+	}
+	else {
+		timo = key->expiry - now.tv_sec;
+
+		if (timo < 60)
+			sprintf(xbuf, "%lus", timo);
+		else if (timo < 60*60)
+			sprintf(xbuf, "%lum", timo / 60);
+		else if (timo < 60*60*24)
+			sprintf(xbuf, "%luh", timo / (60*60));
+		else if (timo < 60*60*24*7)
+			sprintf(xbuf, "%lud", timo / (60*60*24));
+		else
+			sprintf(xbuf, "%luw", timo / (60*60*24*7));
+	}
+
+	seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %06x %5d %5d %-9.9s ",
+		   key->serial,
+		   key->flags & KEY_FLAG_INSTANTIATED	? 'I' : '-',
+		   key->flags & KEY_FLAG_REVOKED	? 'R' : '-',
+		   key->flags & KEY_FLAG_DEAD		? 'D' : '-',
+		   key->flags & KEY_FLAG_IN_QUOTA	? 'Q' : '-',
+		   key->flags & KEY_FLAG_USER_CONSTRUCT	? 'U' : '-',
+		   key->flags & KEY_FLAG_NEGATIVE	? 'N' : '-',
+		   atomic_read(&key->usage),
+		   xbuf,
+		   key->perm,
+		   key->uid,
+		   key->gid,
+		   key->type->name);
+
+	if (key->type->describe)
+		key->type->describe(key, m);
+	seq_putc(m, '\n');
+
+	read_unlock(&key->lock);
+
+	return 0;
+
+}
+
+#endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
+
+/*****************************************************************************/
+/*
+ * implement "/proc/key-users" to provides a list of the key users
+ */
+static int proc_key_users_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &proc_key_users_ops);
+
+}
+
+static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
+{
+	struct rb_node *_p;
+	loff_t pos = *_pos;
+
+	spin_lock(&key_user_lock);
+
+	_p = rb_first(&key_user_tree);
+	while (pos > 0 && _p) {
+		pos--;
+		_p = rb_next(_p);
+	}
+
+	return _p;
+
+}
+
+static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
+{
+	(*_pos)++;
+	return rb_next((struct rb_node *) v);
+
+}
+
+static void proc_key_users_stop(struct seq_file *p, void *v)
+{
+	spin_unlock(&key_user_lock);
+}
+
+static int proc_key_users_show(struct seq_file *m, void *v)
+{
+	struct rb_node *_p = v;
+	struct key_user *user = rb_entry(_p, struct key_user, node);
+
+	seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
+		   user->uid,
+		   atomic_read(&user->usage),
+		   atomic_read(&user->nkeys),
+		   atomic_read(&user->nikeys),
+		   user->qnkeys,
+		   KEYQUOTA_MAX_KEYS,
+		   user->qnbytes,
+		   KEYQUOTA_MAX_BYTES
+		   );
+
+	return 0;
+
+}

security/keys/process_keys.c

@@ -0,0 +1,665 @@
+/* process_keys.c: management of a process's keyrings
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/keyctl.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/* session keyring create vs join semaphore */
+static DECLARE_MUTEX(key_session_sem);
+
+/* the root user's tracking struct */
+struct key_user root_key_user = {
+	.usage		= ATOMIC_INIT(3),
+	.consq		= LIST_HEAD_INIT(root_key_user.consq),
+	.lock		= SPIN_LOCK_UNLOCKED,
+	.nkeys		= ATOMIC_INIT(2),
+	.nikeys		= ATOMIC_INIT(2),
+	.uid		= 0,
+};
+
+/* the root user's UID keyring */
+struct key root_user_keyring = {
+	.usage		= ATOMIC_INIT(1),
+	.serial		= 2,
+	.type		= &key_type_keyring,
+	.user		= &root_key_user,
+	.lock		= RW_LOCK_UNLOCKED,
+	.sem		= __RWSEM_INITIALIZER(root_user_keyring.sem),
+	.perm		= KEY_USR_ALL,
+	.flags		= KEY_FLAG_INSTANTIATED,
+	.description	= "_uid.0",
+#ifdef KEY_DEBUGGING
+	.magic		= KEY_DEBUG_MAGIC,
+#endif
+};
+
+/* the root user's default session keyring */
+struct key root_session_keyring = {
+	.usage		= ATOMIC_INIT(1),
+	.serial		= 1,
+	.type		= &key_type_keyring,
+	.user		= &root_key_user,
+	.lock		= RW_LOCK_UNLOCKED,
+	.sem		= __RWSEM_INITIALIZER(root_session_keyring.sem),
+	.perm		= KEY_USR_ALL,
+	.flags		= KEY_FLAG_INSTANTIATED,
+	.description	= "_uid_ses.0",
+#ifdef KEY_DEBUGGING
+	.magic		= KEY_DEBUG_MAGIC,
+#endif
+};
+
+/*****************************************************************************/
+/*
+ * allocate the keyrings to be associated with a UID
+ */
+int alloc_uid_keyring(struct user_struct *user)
+{
+	struct key *uid_keyring, *session_keyring;
+	char buf[20];
+	int ret;
+
+	/* concoct a default session keyring */
+	sprintf(buf, "_uid_ses.%u", user->uid);
+
+	session_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, 0, NULL);
+	if (IS_ERR(session_keyring)) {
+		ret = PTR_ERR(session_keyring);
+		goto error;
+	}
+
+	/* and a UID specific keyring, pointed to by the default session
+	 * keyring */
+	sprintf(buf, "_uid.%u", user->uid);
+
+	uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, 0,
+				    session_keyring);
+	if (IS_ERR(uid_keyring)) {
+		key_put(session_keyring);
+		ret = PTR_ERR(uid_keyring);
+		goto error;
+	}
+
+	/* install the keyrings */
+	user->uid_keyring = uid_keyring;
+	user->session_keyring = session_keyring;
+	ret = 0;
+
+ error:
+	return ret;
+
+} /* end alloc_uid_keyring() */
+
+/*****************************************************************************/
+/*
+ * deal with the UID changing
+ */
+void switch_uid_keyring(struct user_struct *new_user)
+{
+#if 0 /* do nothing for now */
+	struct key *old;
+
+	/* switch to the new user's session keyring if we were running under
+	 * root's default session keyring */
+	if (new_user->uid != 0 &&
+	    current->session_keyring == &root_session_keyring
+	    ) {
+		atomic_inc(&new_user->session_keyring->usage);
+
+		task_lock(current);
+		old = current->session_keyring;
+		current->session_keyring = new_user->session_keyring;
+		task_unlock(current);
+
+		key_put(old);
+	}
+#endif
+
+} /* end switch_uid_keyring() */
+
+/*****************************************************************************/
+/*
+ * install a fresh thread keyring, discarding the old one
+ */
+int install_thread_keyring(struct task_struct *tsk)
+{
+	struct key *keyring, *old;
+	char buf[20];
+	int ret;
+
+	sprintf(buf, "_tid.%u", tsk->pid);
+
+	keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error;
+	}
+
+	task_lock(tsk);
+	old = tsk->thread_keyring;
+	tsk->thread_keyring = keyring;
+	task_unlock(tsk);
+
+	ret = 0;
+
+	key_put(old);
+ error:
+	return ret;
+
+} /* end install_thread_keyring() */
+
+/*****************************************************************************/
+/*
+ * make sure a process keyring is installed
+ */
+static int install_process_keyring(struct task_struct *tsk)
+{
+	unsigned long flags;
+	struct key *keyring;
+	char buf[20];
+	int ret;
+
+	if (!tsk->signal->process_keyring) {
+		sprintf(buf, "_pid.%u", tsk->tgid);
+
+		keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
+		if (IS_ERR(keyring)) {
+			ret = PTR_ERR(keyring);
+			goto error;
+		}
+
+		/* attach or swap keyrings */
+		spin_lock_irqsave(&tsk->sighand->siglock, flags);
+		if (!tsk->signal->process_keyring) {
+			tsk->signal->process_keyring = keyring;
+			keyring = NULL;
+		}
+		spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+
+		key_put(keyring);
+	}
+
+	ret = 0;
+ error:
+	return ret;
+
+} /* end install_process_keyring() */
+
+/*****************************************************************************/
+/*
+ * install a session keyring, discarding the old one
+ * - if a keyring is not supplied, an empty one is invented
+ */
+static int install_session_keyring(struct task_struct *tsk,
+				   struct key *keyring)
+{
+	unsigned long flags;
+	struct key *old;
+	char buf[20];
+	int ret;
+
+	/* create an empty session keyring */
+	if (!keyring) {
+		sprintf(buf, "_ses.%u", tsk->tgid);
+
+		keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
+		if (IS_ERR(keyring)) {
+			ret = PTR_ERR(keyring);
+			goto error;
+		}
+	}
+	else {
+		atomic_inc(&keyring->usage);
+	}
+
+	/* install the keyring */
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	old = tsk->signal->session_keyring;
+	tsk->signal->session_keyring = keyring;
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+
+	ret = 0;
+
+	key_put(old);
+ error:
+	return ret;
+
+} /* end install_session_keyring() */
+
+/*****************************************************************************/
+/*
+ * copy the keys in a thread group for fork without CLONE_THREAD
+ */
+int copy_thread_group_keys(struct task_struct *tsk)
+{
+	unsigned long flags;
+
+	key_check(current->thread_group->session_keyring);
+	key_check(current->thread_group->process_keyring);
+
+	/* no process keyring yet */
+	tsk->signal->process_keyring = NULL;
+
+	/* same session keyring */
+	spin_lock_irqsave(&current->sighand->siglock, flags);
+	tsk->signal->session_keyring =
+		key_get(current->signal->session_keyring);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+
+	return 0;
+
+} /* end copy_thread_group_keys() */
+
+/*****************************************************************************/
+/*
+ * copy the keys for fork
+ */
+int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
+{
+	key_check(tsk->thread_keyring);
+
+	/* no thread keyring yet */
+	tsk->thread_keyring = NULL;
+	return 0;
+
+} /* end copy_keys() */
+
+/*****************************************************************************/
+/*
+ * dispose of thread group keys upon thread group destruction
+ */
+void exit_thread_group_keys(struct signal_struct *tg)
+{
+	key_put(tg->session_keyring);
+	key_put(tg->process_keyring);
+
+} /* end exit_thread_group_keys() */
+
+/*****************************************************************************/
+/*
+ * dispose of keys upon thread exit
+ */
+void exit_keys(struct task_struct *tsk)
+{
+	key_put(tsk->thread_keyring);
+
+} /* end exit_keys() */
+
+/*****************************************************************************/
+/*
+ * deal with execve()
+ */
+int exec_keys(struct task_struct *tsk)
+{
+	unsigned long flags;
+	struct key *old;
+
+	/* newly exec'd tasks don't get a thread keyring */
+	task_lock(tsk);
+	old = tsk->thread_keyring;
+	tsk->thread_keyring = NULL;
+	task_unlock(tsk);
+
+	key_put(old);
+
+	/* discard the process keyring from a newly exec'd task */
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	old = tsk->signal->process_keyring;
+	tsk->signal->process_keyring = NULL;
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+
+	key_put(old);
+
+	return 0;
+
+} /* end exec_keys() */
+
+/*****************************************************************************/
+/*
+ * deal with SUID programs
+ * - we might want to make this invent a new session keyring
+ */
+int suid_keys(struct task_struct *tsk)
+{
+	return 0;
+
+} /* end suid_keys() */
+
+/*****************************************************************************/
+/*
+ * the filesystem user ID changed
+ */
+void key_fsuid_changed(struct task_struct *tsk)
+{
+	/* update the ownership of the thread keyring */
+	if (tsk->thread_keyring) {
+		down_write(&tsk->thread_keyring->sem);
+		write_lock(&tsk->thread_keyring->lock);
+		tsk->thread_keyring->uid = tsk->fsuid;
+		write_unlock(&tsk->thread_keyring->lock);
+		up_write(&tsk->thread_keyring->sem);
+	}
+
+} /* end key_fsuid_changed() */
+
+/*****************************************************************************/
+/*
+ * the filesystem group ID changed
+ */
+void key_fsgid_changed(struct task_struct *tsk)
+{
+	/* update the ownership of the thread keyring */
+	if (tsk->thread_keyring) {
+		down_write(&tsk->thread_keyring->sem);
+		write_lock(&tsk->thread_keyring->lock);
+		tsk->thread_keyring->gid = tsk->fsgid;
+		write_unlock(&tsk->thread_keyring->lock);
+		up_write(&tsk->thread_keyring->sem);
+	}
+
+} /* end key_fsgid_changed() */
+
+/*****************************************************************************/
+/*
+ * search the process keyrings for the first matching key
+ * - we use the supplied match function to see if the description (or other
+ *   feature of interest) matches
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we found only negative matching keys
+ */
+struct key *search_process_keyrings_aux(struct key_type *type,
+					const void *description,
+					key_match_func_t match)
+{
+	struct task_struct *tsk = current;
+	unsigned long flags;
+	struct key *key, *ret, *err, *tmp;
+
+	/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
+	 * searchable, but we failed to find a key or we found a negative key;
+	 * otherwise we want to return a sample error (probably -EACCES) if
+	 * none of the keyrings were searchable
+	 *
+	 * in terms of priority: success > -ENOKEY > -EAGAIN > other error
+	 */
+	key = NULL;
+	ret = NULL;
+	err = ERR_PTR(-EAGAIN);
+
+	/* search the thread keyring first */
+	if (tsk->thread_keyring) {
+		key = keyring_search_aux(tsk->thread_keyring, type,
+					 description, match);
+		if (!IS_ERR(key))
+			goto found;
+
+		switch (PTR_ERR(key)) {
+		case -EAGAIN: /* no key */
+			if (ret)
+				break;
+		case -ENOKEY: /* negative key */
+			ret = key;
+			break;
+		default:
+			err = key;
+			break;
+		}
+	}
+
+	/* search the process keyring second */
+	if (tsk->signal->process_keyring) {
+		key = keyring_search_aux(tsk->signal->process_keyring,
+					 type, description, match);
+		if (!IS_ERR(key))
+			goto found;
+
+		switch (PTR_ERR(key)) {
+		case -EAGAIN: /* no key */
+			if (ret)
+				break;
+		case -ENOKEY: /* negative key */
+			ret = key;
+			break;
+		default:
+			err = key;
+			break;
+		}
+	}
+
+	/* search the session keyring last */
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+
+	tmp = tsk->signal->session_keyring;
+	if (!tmp)
+		tmp = tsk->user->session_keyring;
+	atomic_inc(&tmp->usage);
+
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+
+	key = keyring_search_aux(tmp, type, description, match);
+	key_put(tmp);
+	if (!IS_ERR(key))
+		goto found;
+
+	switch (PTR_ERR(key)) {
+	case -EAGAIN: /* no key */
+		if (ret)
+			break;
+	case -ENOKEY: /* negative key */
+		ret = key;
+		break;
+	default:
+		err = key;
+		break;
+	}
+
+	/* no key - decide on the error we're going to go for */
+	key = ret ? ret : err;
+
+ found:
+	return key;
+
+} /* end search_process_keyrings_aux() */
+
+/*****************************************************************************/
+/*
+ * search the process keyrings for the first matching key
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we found only negative matching keys
+ */
+struct key *search_process_keyrings(struct key_type *type,
+				    const char *description)
+{
+	return search_process_keyrings_aux(type, description, type->match);
+
+} /* end search_process_keyrings() */
+
+/*****************************************************************************/
+/*
+ * lookup a key given a key ID from userspace with a given permissions mask
+ * - don't create special keyrings unless so requested
+ * - partially constructed keys aren't found unless requested
+ */
+struct key *lookup_user_key(key_serial_t id, int create, int partial,
+			    key_perm_t perm)
+{
+	struct task_struct *tsk = current;
+	unsigned long flags;
+	struct key *key;
+	int ret;
+
+	key = ERR_PTR(-ENOKEY);
+
+	switch (id) {
+	case KEY_SPEC_THREAD_KEYRING:
+		if (!tsk->thread_keyring) {
+			if (!create)
+				goto error;
+
+			ret = install_thread_keyring(tsk);
+			if (ret < 0) {
+				key = ERR_PTR(ret);
+				goto error;
+			}
+		}
+
+		key = tsk->thread_keyring;
+		atomic_inc(&key->usage);
+		break;
+
+	case KEY_SPEC_PROCESS_KEYRING:
+		if (!tsk->signal->process_keyring) {
+			if (!create)
+				goto error;
+
+			ret = install_process_keyring(tsk);
+			if (ret < 0) {
+				key = ERR_PTR(ret);
+				goto error;
+			}
+		}
+
+		key = tsk->signal->process_keyring;
+		atomic_inc(&key->usage);
+		break;
+
+	case KEY_SPEC_SESSION_KEYRING:
+		if (!tsk->signal->session_keyring) {
+			/* always install a session keyring upon access if one
+			 * doesn't exist yet */
+			ret = install_session_keyring(
+			       tsk, tsk->user->session_keyring);
+			if (ret < 0)
+				goto error;
+		}
+
+		spin_lock_irqsave(&tsk->sighand->siglock, flags);
+		key = tsk->signal->session_keyring;
+		atomic_inc(&key->usage);
+		spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+		break;
+
+	case KEY_SPEC_USER_KEYRING:
+		key = tsk->user->uid_keyring;
+		atomic_inc(&key->usage);
+		break;
+
+	case KEY_SPEC_USER_SESSION_KEYRING:
+		key = tsk->user->session_keyring;
+		atomic_inc(&key->usage);
+		break;
+
+	case KEY_SPEC_GROUP_KEYRING:
+		/* group keyrings are not yet supported */
+		key = ERR_PTR(-EINVAL);
+		goto error;
+
+	default:
+		key = ERR_PTR(-EINVAL);
+		if (id < 1)
+			goto error;
+
+		key = key_lookup(id);
+		if (IS_ERR(key))
+			goto error;
+		break;
+	}
+
+	/* check the status and permissions */
+	if (perm) {
+		ret = key_validate(key);
+		if (ret < 0)
+			goto invalid_key;
+	}
+
+	ret = -EIO;
+	if (!partial && !(key->flags & KEY_FLAG_INSTANTIATED))
+		goto invalid_key;
+
+	ret = -EACCES;
+	if (!key_permission(key, perm))
+		goto invalid_key;
+
+ error:
+	return key;
+
+ invalid_key:
+	key_put(key);
+	key = ERR_PTR(ret);
+	goto error;
+
+} /* end lookup_user_key() */
+
+/*****************************************************************************/
+/*
+ * join the named keyring as the session keyring if possible, or attempt to
+ * create a new one of that name if not
+ * - if the name is NULL, an empty anonymous keyring is installed instead
+ * - named session keyring joining is done with a semaphore held
+ */
+long join_session_keyring(const char *name)
+{
+	struct task_struct *tsk = current;
+	unsigned long flags;
+	struct key *keyring;
+	long ret;
+
+	/* if no name is provided, install an anonymous keyring */
+	if (!name) {
+		ret = install_session_keyring(tsk, NULL);
+		if (ret < 0)
+			goto error;
+
+		spin_lock_irqsave(&tsk->sighand->siglock, flags);
+		ret = tsk->signal->session_keyring->serial;
+		spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+		goto error;
+	}
+
+	/* allow the user to join or create a named keyring */
+	down(&key_session_sem);
+
+	/* look for an existing keyring of this name */
+	keyring = find_keyring_by_name(name, 0);
+	if (PTR_ERR(keyring) == -ENOKEY) {
+		/* not found - try and create a new one */
+		keyring = keyring_alloc(name, tsk->uid, tsk->gid, 0, NULL);
+		if (IS_ERR(keyring)) {
+			ret = PTR_ERR(keyring);
+			goto error;
+		}
+	}
+	else if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto error2;
+	}
+
+	/* we've got a keyring - now to install it */
+	ret = install_session_keyring(tsk, keyring);
+	if (ret < 0)
+		goto error2;
+
+	ret = keyring->serial;
+	key_put(keyring);
+
+ error2:
+	up(&key_session_sem);
+ error:
+	return ret;
+
+} /* end join_session_keyring() */

security/keys/request_key.c

@@ -0,0 +1,359 @@
+/* request_key.c: request a key from userspace
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kmod.h>
+#include <linux/err.h>
+#include "internal.h"
+
+struct key_construction {
+	struct list_head	link;	/* link in construction queue */
+	struct key		*key;	/* key being constructed */
+};
+
+/* when waiting for someone else's keys, you get added to this */
+DECLARE_WAIT_QUEUE_HEAD(request_key_conswq);
+
+/*****************************************************************************/
+/*
+ * request userspace finish the construction of a key
+ * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring> <info>"
+ * - if callout_info is an empty string, it'll be rendered as a "-" instead
+ */
+static int call_request_key(struct key *key,
+			    const char *op,
+			    const char *callout_info)
+{
+	struct task_struct *tsk = current;
+	unsigned long flags;
+	key_serial_t prkey, sskey;
+	char *argv[10], *envp[3], uid_str[12], gid_str[12];
+	char key_str[12], keyring_str[3][12];
+	int i;
+
+	/* record the UID and GID */
+	sprintf(uid_str, "%d", current->fsuid);
+	sprintf(gid_str, "%d", current->fsgid);
+
+	/* we say which key is under construction */
+	sprintf(key_str, "%d", key->serial);
+
+	/* we specify the process's default keyrings */
+	sprintf(keyring_str[0], "%d",
+		tsk->thread_keyring ? tsk->thread_keyring->serial : 0);
+
+	prkey = 0;
+	if (tsk->signal->process_keyring)
+		prkey = tsk->signal->process_keyring->serial;
+
+	sskey = 0;
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	if (tsk->signal->session_keyring)
+		sskey = tsk->signal->session_keyring->serial;
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+
+
+	if (!sskey)
+		sskey = tsk->user->session_keyring->serial;
+
+	sprintf(keyring_str[1], "%d", prkey);
+	sprintf(keyring_str[2], "%d", sskey);
+
+	/* set up a minimal environment */
+	i = 0;
+	envp[i++] = "HOME=/";
+	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+	envp[i] = NULL;
+
+	/* set up the argument list */
+	i = 0;
+	argv[i++] = "/sbin/request-key";
+	argv[i++] = (char *) op;
+	argv[i++] = key_str;
+	argv[i++] = uid_str;
+	argv[i++] = gid_str;
+	argv[i++] = keyring_str[0];
+	argv[i++] = keyring_str[1];
+	argv[i++] = keyring_str[2];
+	argv[i++] = callout_info[0] ? (char *) callout_info : "-";
+	argv[i] = NULL;
+
+	/* do it */
+	return call_usermodehelper(argv[0], argv, envp, 1);
+
+} /* end call_request_key() */
+
+/*****************************************************************************/
+/*
+ * call out to userspace for the key
+ * - called with the construction sem held, but the sem is dropped here
+ * - we ignore program failure and go on key status instead
+ */
+static struct key *__request_key_construction(struct key_type *type,
+					      const char *description,
+					      const char *callout_info)
+{
+	struct key_construction cons;
+	struct timespec now;
+	struct key *key;
+	int ret, negative;
+
+	/* create a key and add it to the queue */
+	key = key_alloc(type, description,
+			current->fsuid, current->fsgid, KEY_USR_ALL, 0);
+	if (IS_ERR(key))
+		goto alloc_failed;
+
+	write_lock(&key->lock);
+	key->flags |= KEY_FLAG_USER_CONSTRUCT;
+	write_unlock(&key->lock);
+
+	cons.key = key;
+	list_add_tail(&cons.link, &key->user->consq);
+
+	/* we drop the construction sem here on behalf of the caller */
+	up_write(&key_construction_sem);
+
+	/* make the call */
+	ret = call_request_key(key, "create", callout_info);
+	if (ret < 0)
+		goto request_failed;
+
+	/* if the key wasn't instantiated, then we want to give an error */
+	ret = -ENOKEY;
+	if (!(key->flags & KEY_FLAG_INSTANTIATED))
+		goto request_failed;
+
+	down_write(&key_construction_sem);
+	list_del(&cons.link);
+	up_write(&key_construction_sem);
+
+	/* also give an error if the key was negatively instantiated */
+ check_not_negative:
+	if (key->flags & KEY_FLAG_NEGATIVE) {
+		key_put(key);
+		key = ERR_PTR(-ENOKEY);
+	}
+
+ out:
+	return key;
+
+ request_failed:
+	/* it wasn't instantiated
+	 * - remove from construction queue
+	 * - mark the key as dead
+	 */
+	negative = 0;
+	down_write(&key_construction_sem);
+
+	list_del(&cons.link);
+
+	write_lock(&key->lock);
+	key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
+
+	/* check it didn't get instantiated between the check and the down */
+	if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
+		key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE;
+		negative = 1;
+	}
+
+	write_unlock(&key->lock);
+	up_write(&key_construction_sem);
+
+	if (!negative)
+		goto check_not_negative; /* surprisingly, the key got
+					  * instantiated */
+
+	/* set the timeout and store in the session keyring if we can */
+	now = current_kernel_time();
+	key->expiry = now.tv_sec + key_negative_timeout;
+
+	if (current->signal->session_keyring) {
+		unsigned long flags;
+		struct key *keyring;
+
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		keyring = current->signal->session_keyring;
+		atomic_inc(&keyring->usage);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
+
+		key_link(keyring, key);
+		key_put(keyring);
+	}
+
+	key_put(key);
+
+	/* notify anyone who was waiting */
+	wake_up_all(&request_key_conswq);
+
+	key = ERR_PTR(ret);
+	goto out;
+
+ alloc_failed:
+	up_write(&key_construction_sem);
+	goto out;
+
+} /* end __request_key_construction() */
+
+/*****************************************************************************/
+/*
+ * call out to userspace to request the key
+ * - we check the construction queue first to see if an appropriate key is
+ *   already being constructed by userspace
+ */
+static struct key *request_key_construction(struct key_type *type,
+					    const char *description,
+					    struct key_user *user,
+					    const char *callout_info)
+{
+	struct key_construction *pcons;
+	struct key *key, *ckey;
+
+	DECLARE_WAITQUEUE(myself, current);
+
+	/* see if there's such a key under construction already */
+	down_write(&key_construction_sem);
+
+	list_for_each_entry(pcons, &user->consq, link) {
+		ckey = pcons->key;
+
+		if (ckey->type != type)
+			continue;
+
+		if (type->match(ckey, description))
+			goto found_key_under_construction;
+	}
+
+	/* see about getting userspace to construct the key */
+	key = __request_key_construction(type, description, callout_info);
+ error:
+	return key;
+
+	/* someone else has the same key under construction
+	 * - we want to keep an eye on their key
+	 */
+ found_key_under_construction:
+	atomic_inc(&ckey->usage);
+	up_write(&key_construction_sem);
+
+	/* wait for the key to be completed one way or another */
+	add_wait_queue(&request_key_conswq, &myself);
+
+	for (;;) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		if (!(ckey->flags & KEY_FLAG_USER_CONSTRUCT))
+			break;
+		schedule();
+	}
+
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(&request_key_conswq, &myself);
+
+	/* we'll need to search this process's keyrings to see if the key is
+	 * now there since we can't automatically assume it's also available
+	 * there */
+	key_put(ckey);
+	ckey = NULL;
+
+	key = NULL; /* request a retry */
+	goto error;
+
+} /* end request_key_construction() */
+
+/*****************************************************************************/
+/*
+ * request a key
+ * - search the process's keyrings
+ * - check the list of keys being created or updated
+ * - call out to userspace for a key if requested (supplementary info can be
+ *   passed)
+ */
+struct key *request_key(struct key_type *type,
+			const char *description,
+			const char *callout_info)
+{
+	struct key_user *user;
+	struct key *key;
+
+	/* search all the process keyrings for a key */
+	key = search_process_keyrings_aux(type, description, type->match);
+
+	if (PTR_ERR(key) == -EAGAIN) {
+		/* the search failed, but the keyrings were searchable, so we
+		 * should consult userspace if we can */
+		key = ERR_PTR(-ENOKEY);
+		if (!callout_info)
+			goto error;
+
+		/* - get hold of the user's construction queue */
+		user = key_user_lookup(current->fsuid);
+		if (!user) {
+			key = ERR_PTR(-ENOMEM);
+			goto error;
+		}
+
+		for (;;) {
+			/* ask userspace (returns NULL if it waited on a key
+			 * being constructed) */
+			key = request_key_construction(type, description,
+						       user, callout_info);
+			if (key)
+				break;
+
+			/* someone else made the key we want, so we need to
+			 * search again as it might now be available to us */
+			key = search_process_keyrings_aux(type, description,
+							  type->match);
+			if (PTR_ERR(key) != -EAGAIN)
+				break;
+		}
+
+		key_user_put(user);
+	}
+
+ error:
+	return key;
+
+} /* end request_key() */
+
+EXPORT_SYMBOL(request_key);
+
+/*****************************************************************************/
+/*
+ * validate a key
+ */
+int key_validate(struct key *key)
+{
+	struct timespec now;
+	int ret = 0;
+
+	if (key) {
+		/* check it's still accessible */
+		ret = -EKEYREVOKED;
+		if (key->flags & (KEY_FLAG_REVOKED | KEY_FLAG_DEAD))
+			goto error;
+
+		/* check it hasn't expired */
+		ret = 0;
+		if (key->expiry) {
+			now = current_kernel_time();
+			if (now.tv_sec >= key->expiry)
+				ret = -EKEYEXPIRED;
+		}
+	}
+
+ error:
+	return ret;
+
+} /* end key_validate() */
+
+EXPORT_SYMBOL(key_validate);

security/keys/user_defined.c

@@ -0,0 +1,191 @@
+/* user_defined.c: user defined key type
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+static int user_instantiate(struct key *key, const void *data, size_t datalen);
+static int user_duplicate(struct key *key, const struct key *source);
+static int user_update(struct key *key, const void *data, size_t datalen);
+static int user_match(const struct key *key, const void *criterion);
+static void user_destroy(struct key *key);
+static void user_describe(const struct key *user, struct seq_file *m);
+static long user_read(const struct key *key,
+		      char __user *buffer, size_t buflen);
+
+/*
+ * user defined keys take an arbitrary string as the description and an
+ * arbitrary blob of data as the payload
+ */
+struct key_type key_type_user = {
+	.name		= "user",
+	.instantiate	= user_instantiate,
+	.duplicate	= user_duplicate,
+	.update		= user_update,
+	.match		= user_match,
+	.destroy	= user_destroy,
+	.describe	= user_describe,
+	.read		= user_read,
+};
+
+/*****************************************************************************/
+/*
+ * instantiate a user defined key
+ */
+static int user_instantiate(struct key *key, const void *data, size_t datalen)
+{
+	int ret;
+
+	ret = -EINVAL;
+	if (datalen <= 0 || datalen > 32767 || !data)
+		goto error;
+
+	ret = key_payload_reserve(key, datalen);
+	if (ret < 0)
+		goto error;
+
+	/* attach the data */
+	ret = -ENOMEM;
+	key->payload.data = kmalloc(datalen, GFP_KERNEL);
+	if (!key->payload.data)
+		goto error;
+
+	memcpy(key->payload.data, data, datalen);
+	ret = 0;
+
+ error:
+	return ret;
+
+} /* end user_instantiate() */
+
+/*****************************************************************************/
+/*
+ * duplicate a user defined key
+ */
+static int user_duplicate(struct key *key, const struct key *source)
+{
+	int ret;
+
+	/* just copy the payload */
+	ret = -ENOMEM;
+	key->payload.data = kmalloc(source->datalen, GFP_KERNEL);
+
+	if (key->payload.data) {
+		key->datalen = source->datalen;
+		memcpy(key->payload.data, source->payload.data, source->datalen);
+		ret = 0;
+	}
+
+	return ret;
+
+} /* end user_duplicate() */
+
+/*****************************************************************************/
+/*
+ * update a user defined key
+ */
+static int user_update(struct key *key, const void *data, size_t datalen)
+{
+	void *new, *zap;
+	int ret;
+
+	ret = -EINVAL;
+	if (datalen <= 0 || datalen > 32767 || !data)
+		goto error;
+
+	/* copy the data */
+	ret = -ENOMEM;
+	new = kmalloc(datalen, GFP_KERNEL);
+	if (!new)
+		goto error;
+
+	memcpy(new, data, datalen);
+
+	/* check the quota and attach the new data */
+	zap = new;
+	write_lock(&key->lock);
+
+	ret = key_payload_reserve(key, datalen);
+
+	if (ret == 0) {
+		/* attach the new data, displacing the old */
+		zap = key->payload.data;
+		key->payload.data = new;
+		key->expiry = 0;
+	}
+
+	write_unlock(&key->lock);
+	kfree(zap);
+
+ error:
+	return ret;
+
+} /* end user_update() */
+
+/*****************************************************************************/
+/*
+ * match users on their name
+ */
+static int user_match(const struct key *key, const void *description)
+{
+	return strcmp(key->description, description) == 0;
+
+} /* end user_match() */
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a user
+ */
+static void user_destroy(struct key *key)
+{
+	kfree(key->payload.data);
+
+} /* end user_destroy() */
+
+/*****************************************************************************/
+/*
+ * describe the user
+ */
+static void user_describe(const struct key *key, struct seq_file *m)
+{
+	seq_puts(m, key->description);
+
+	seq_printf(m, ": %u", key->datalen);
+
+} /* end user_describe() */
+
+/*****************************************************************************/
+/*
+ * read the key data
+ */
+static long user_read(const struct key *key,
+		      char __user *buffer, size_t buflen)
+{
+	long ret = key->datalen;
+
+	/* we can return the data as is */
+	if (buffer && buflen > 0) {
+		if (buflen > key->datalen)
+			buflen = key->datalen;
+
+		if (copy_to_user(buffer, key->payload.data, buflen) != 0)
+			ret = -EFAULT;
+	}
+
+	return ret;
+
+} /* end user_read() */