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/* Authentication token and access key management

 *

 * Copyright (C) 2004, 2007 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.

 *

 *

 * See Documentation/keys.txt for information on keys/keyrings.

 */

#ifndef _LINUX_KEY_H

#define _LINUX_KEY_H

#include <linux/types.h>

#include <linux/list.h>

#include <linux/rbtree.h>

#include <linux/rcupdate.h>

#include <asm/atomic.h>

#ifdef __KERNEL__

/* key handle serial number */

typedef int32_t key_serial_t;

/* key handle permissions mask */

typedef uint32_t key_perm_t;

struct key;

#ifdef CONFIG_KEYS

#undef KEY_DEBUGGING

#define KEY_POS_VIEW    0x01000000      /* possessor can view a key's attributes */

#define KEY_POS_READ    0x02000000      /* possessor can read key payload / view keyring */

#define KEY_POS_WRITE   0x04000000      /* possessor can update key payload / add link to keyring */

#define KEY_POS_SEARCH  0x08000000      /* possessor can find a key in search / search a keyring */

#define KEY_POS_LINK    0x10000000      /* possessor can create a link to a key/keyring */

#define KEY_POS_SETATTR 0x20000000      /* possessor can set key attributes */

#define KEY_POS_ALL     0x3f000000

#define KEY_USR_VIEW    0x00010000      /* user permissions... */

#define KEY_USR_READ    0x00020000

#define KEY_USR_WRITE   0x00040000

#define KEY_USR_SEARCH  0x00080000

#define KEY_USR_LINK    0x00100000

#define KEY_USR_SETATTR 0x00200000

#define KEY_USR_ALL     0x003f0000

#define KEY_GRP_VIEW    0x00000100      /* group permissions... */

#define KEY_GRP_READ    0x00000200

#define KEY_GRP_WRITE   0x00000400

#define KEY_GRP_SEARCH  0x00000800

#define KEY_GRP_LINK    0x00001000

#define KEY_GRP_SETATTR 0x00002000

#define KEY_GRP_ALL     0x00003f00

#define KEY_OTH_VIEW    0x00000001      /* third party permissions... */

#define KEY_OTH_READ    0x00000002

#define KEY_OTH_WRITE   0x00000004

#define KEY_OTH_SEARCH  0x00000008

#define KEY_OTH_LINK    0x00000010

#define KEY_OTH_SETATTR 0x00000020

#define KEY_OTH_ALL     0x0000003f

struct seq_file;

struct user_struct;

struct signal_struct;

struct key_type;

struct key_owner;

struct keyring_list;

struct keyring_name;

/*****************************************************************************/

/*

 * key reference with possession attribute handling

 *

 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually

 * defined. This is because we abuse the bottom bit of the reference to carry a

 * flag to indicate whether the calling process possesses that key in one of

 * its keyrings.

 *

 * the key_ref_t has been made a separate type so that the compiler can reject

 * attempts to dereference it without proper conversion.

 *

 * the three functions are used to assemble and disassemble references

 */

typedef struct __key_reference_with_attributes *key_ref_t;

static inline key_ref_t make_key_ref(const struct key *key,

                                     unsigned long possession)

{

        return (key_ref_t) ((unsigned long) key | possession);

}

static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)

{

        return (struct key *) ((unsigned long) key_ref & ~1UL);

}

static inline unsigned long is_key_possessed(const key_ref_t key_ref)

{

        return (unsigned long) key_ref & 1UL;

}

/*****************************************************************************/

/*

 * authentication token / access credential / keyring

 * - types of key include:

 *   - keyrings

 *   - disk encryption IDs

 *   - Kerberos TGTs and tickets

 */

struct key {

        atomic_t                usage;          /* number of references */

        key_serial_t            serial;         /* key serial number */

        struct rb_node          serial_node;

        struct key_type         *type;          /* type of key */

        struct rw_semaphore     sem;            /* change vs change sem */

        struct key_user         *user;          /* owner of this key */

        void                    *security;      /* security data for this key */

        time_t                  expiry;         /* time at which key expires (or 0) */

        uid_t                   uid;

        gid_t                   gid;

        key_perm_t              perm;           /* access permissions */

        unsigned short          quotalen;       /* length added to quota */

        unsigned short          datalen;        /* payload data length

                                                 * - may not match RCU dereferenced payload

                                                 * - payload should contain own length

                                                 */

#ifdef KEY_DEBUGGING

        unsigned                magic;

#define KEY_DEBUG_MAGIC         0x18273645u

#define KEY_DEBUG_MAGIC_X       0xf8e9dacbu

#endif

        unsigned long           flags;          /* status flags (change with bitops) */

#define KEY_FLAG_INSTANTIATED   0        /* set if key has been instantiated */

#define KEY_FLAG_DEAD           1       /* set if key type has been deleted */

#define KEY_FLAG_REVOKED        2       /* set if key had been revoked */

#define KEY_FLAG_IN_QUOTA       3       /* set if key consumes quota */

#define KEY_FLAG_USER_CONSTRUCT 4       /* set if key is being constructed in userspace */

#define KEY_FLAG_NEGATIVE       5       /* set if key is negative */

        /* the description string

         * - this is used to match a key against search criteria

         * - this should be a printable string

         * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"

         */

        char                    *description;

        /* type specific data

         * - this is used by the keyring type to index the name

         */

        union {

                struct list_head        link;

                unsigned long           x[2];

                void                    *p[2];

        } type_data;

        /* key data

         * - this is used to hold the data actually used in cryptography or

         *   whatever

         */

        union {

                unsigned long           value;

                void                    *data;

                struct keyring_list     *subscriptions;

        } payload;

};

extern struct key *key_alloc(struct key_type *type,

                             const char *desc,

                             uid_t uid, gid_t gid,

                             struct task_struct *ctx,

                             key_perm_t perm,

                             unsigned long flags);

#define KEY_ALLOC_IN_QUOTA      0x0000  /* add to quota, reject if would overrun */

#define KEY_ALLOC_QUOTA_OVERRUN 0x0001  /* add to quota, permit even if overrun */

#define KEY_ALLOC_NOT_IN_QUOTA  0x0002  /* not in quota */

extern void key_revoke(struct key *key);

extern void key_put(struct key *key);

static inline struct key *key_get(struct key *key)

{

        if (key)

                atomic_inc(&key->usage);

        return key;

}

static inline void key_ref_put(key_ref_t key_ref)

{

        key_put(key_ref_to_ptr(key_ref));

}

extern struct key *request_key(struct key_type *type,

                               const char *description,

                               const char *callout_info);

extern struct key *request_key_with_auxdata(struct key_type *type,

                                            const char *description,

                                            const char *callout_info,

                                            void *aux);

extern struct key *request_key_async(struct key_type *type,

                                     const char *description,

                                     const char *callout_info);

extern struct key *request_key_async_with_auxdata(struct key_type *type,

                                                  const char *description,

                                                  const char *callout_info,

                                                  void *aux);

extern int wait_for_key_construction(struct key *key, bool intr);

extern int key_validate(struct key *key);

extern key_ref_t key_create_or_update(key_ref_t keyring,

                                      const char *type,

                                      const char *description,

                                      const void *payload,

                                      size_t plen,

                                      unsigned long flags);

extern int key_update(key_ref_t key,

                      const void *payload,

                      size_t plen);

extern int key_link(struct key *keyring,

                    struct key *key);

extern int key_unlink(struct key *keyring,

                      struct key *key);

extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,

                                 struct task_struct *ctx,

                                 unsigned long flags,

                                 struct key *dest);

extern int keyring_clear(struct key *keyring);

extern key_ref_t keyring_search(key_ref_t keyring,

                                struct key_type *type,

                                const char *description);

extern int keyring_add_key(struct key *keyring,

                           struct key *key);

extern struct key *key_lookup(key_serial_t id);

#define key_serial(key) ((key) ? (key)->serial : 0)

/*

 * the userspace interface

 */

extern struct key root_user_keyring, root_session_keyring;

extern int alloc_uid_keyring(struct user_struct *user,

                             struct task_struct *ctx);

extern void switch_uid_keyring(struct user_struct *new_user);

extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);

extern int copy_thread_group_keys(struct task_struct *tsk);

extern void exit_keys(struct task_struct *tsk);

extern void exit_thread_group_keys(struct signal_struct *tg);

extern int suid_keys(struct task_struct *tsk);

extern int exec_keys(struct task_struct *tsk);

extern void key_fsuid_changed(struct task_struct *tsk);

extern void key_fsgid_changed(struct task_struct *tsk);

extern void key_init(void);

#define __install_session_keyring(tsk, keyring)                 \

({                                                              \

        struct key *old_session = tsk->signal->session_keyring; \

        tsk->signal->session_keyring = keyring;                 \

        old_session;                                            \

})

#else /* CONFIG_KEYS */

#define key_validate(k)                 0

#define key_serial(k)                   0

#define key_get(k)                      ({ NULL; })

#define key_put(k)                      do { } while(0)

#define key_ref_put(k)                  do { } while(0)

#define make_key_ref(k, p)                      ({ NULL; })

#define key_ref_to_ptr(k)               ({ NULL; })

#define is_key_possessed(k)             0

#define alloc_uid_keyring(u,c)          0

#define switch_uid_keyring(u)           do { } while(0)

#define __install_session_keyring(t, k) ({ NULL; })

#define copy_keys(f,t)                  0

#define copy_thread_group_keys(t)       0

#define exit_keys(t)                    do { } while(0)

#define exit_thread_group_keys(tg)      do { } while(0)

#define suid_keys(t)                    do { } while(0)

#define exec_keys(t)                    do { } while(0)

#define key_fsuid_changed(t)            do { } while(0)

#define key_fsgid_changed(t)            do { } while(0)

#define key_init()                      do { } while(0)

/* Initial keyrings */

extern struct key root_user_keyring;

extern struct key root_session_keyring;

#endif /* CONFIG_KEYS */

#endif /* __KERNEL__ */

#endif /* _LINUX_KEY_H */