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linux/security/keys/internal.h
David Howells b5f545c880 [PATCH] keys: Permit running process to instantiate keys 
Make it possible for a running process (such as gssapid) to be able to
instantiate a key, as was requested by Trond Myklebust for NFS4.

The patch makes the following changes:

 (1) A new, optional key type method has been added. This permits a key type
     to intercept requests at the point /sbin/request-key is about to be
     spawned and do something else with them - passing them over the
     rpc_pipefs files or netlink sockets for instance.

     The uninstantiated key, the authorisation key and the intended operation
     name are passed to the method.

 (2) The callout_info is no longer passed as an argument to /sbin/request-key
     to prevent unauthorised viewing of this data using ps or by looking in
     /proc/pid/cmdline.

     This means that the old /sbin/request-key program will not work with the
     patched kernel as it will expect to see an extra argument that is no
     longer there.

     A revised keyutils package will be made available tomorrow.

 (3) The callout_info is now attached to the authorisation key. Reading this
     key will retrieve the information.

 (4) A new field has been added to the task_struct. This holds the
     authorisation key currently active for a thread. Searches now look here
     for the caller's set of keys rather than looking for an auth key in the
     lowest level of the session keyring.

     This permits a thread to be servicing multiple requests at once and to
     switch between them. Note that this is per-thread, not per-process, and
     so is usable in multithreaded programs.

     The setting of this field is inherited across fork and exec.

 (5) A new keyctl function (KEYCTL_ASSUME_AUTHORITY) has been added that
     permits a thread to assume the authority to deal with an uninstantiated
     key. Assumption is only permitted if the authorisation key associated
     with the uninstantiated key is somewhere in the thread's keyrings.

     This function can also clear the assumption.

 (6) A new magic key specifier has been added to refer to the currently
     assumed authorisation key (KEY_SPEC_REQKEY_AUTH_KEY).

 (7) Instantiation will only proceed if the appropriate authorisation key is
     assumed first. The assumed authorisation key is discarded if
     instantiation is successful.

 (8) key_validate() is moved from the file of request_key functions to the
     file of permissions functions.

 (9) The documentation is updated.

From: <Valdis.Kletnieks@vt.edu>

    Build fix.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:53 -08:00

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/* internal.h: authentication token and access key management internal defs
*
* Copyright (C) 2003-5 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>
#if 0
#define kenter(FMT, a...) printk("==> %s("FMT")\n",__FUNCTION__ , ## a)
#define kleave(FMT, a...) printk("<== %s()"FMT"\n",__FUNCTION__ , ## a)
#define kdebug(FMT, a...) printk(FMT"\n" , ## a)
#else
#define kenter(FMT, a...) do {} while(0)
#define kleave(FMT, a...) do {} while(0)
#define kdebug(FMT, a...) do {} while(0)
#endif
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 key_ref_t __keyring_search_one(key_ref_t keyring_ref,
const struct key_type *type,
const char *description,
key_perm_t perm);
extern struct key *keyring_search_instkey(struct key *keyring,
key_serial_t target_id);
typedef int (*key_match_func_t)(const struct key *, const void *);
extern key_ref_t keyring_search_aux(key_ref_t keyring_ref,
struct task_struct *tsk,
struct key_type *type,
const void *description,
key_match_func_t match);
extern key_ref_t search_process_keyrings(struct key_type *type,
const void *description,
key_match_func_t match,
struct task_struct *tsk);
extern struct key *find_keyring_by_name(const char *name, key_serial_t bound);
extern int install_thread_keyring(struct task_struct *tsk);
extern int install_process_keyring(struct task_struct *tsk);
extern struct key *request_key_and_link(struct key_type *type,
const char *description,
const char *callout_info,
struct key *dest_keyring);
/*
* request_key authorisation
*/
struct request_key_auth {
struct key *target_key;
struct task_struct *context;
const char *callout_info;
pid_t pid;
};
extern struct key_type key_type_request_key_auth;
extern struct key *request_key_auth_new(struct key *target,
const char *callout_info);
extern struct key *key_get_instantiation_authkey(key_serial_t target_id);
/*
* 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);
extern long keyctl_set_reqkey_keyring(int);
extern long keyctl_set_timeout(key_serial_t, unsigned);
extern long keyctl_assume_authority(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 */
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