291 lines
8.4 KiB
C
291 lines
8.4 KiB
C
/* Credentials management
|
|
*
|
|
* Copyright (C) 2008 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 Licence
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
*/
|
|
|
|
#ifndef _LINUX_CRED_H
|
|
#define _LINUX_CRED_H
|
|
|
|
#include <linux/capability.h>
|
|
#include <linux/key.h>
|
|
#include <asm/atomic.h>
|
|
|
|
struct user_struct;
|
|
struct cred;
|
|
|
|
/*
|
|
* COW Supplementary groups list
|
|
*/
|
|
#define NGROUPS_SMALL 32
|
|
#define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(gid_t)))
|
|
|
|
struct group_info {
|
|
atomic_t usage;
|
|
int ngroups;
|
|
int nblocks;
|
|
gid_t small_block[NGROUPS_SMALL];
|
|
gid_t *blocks[0];
|
|
};
|
|
|
|
/**
|
|
* get_group_info - Get a reference to a group info structure
|
|
* @group_info: The group info to reference
|
|
*
|
|
* This gets a reference to a set of supplementary groups.
|
|
*
|
|
* If the caller is accessing a task's credentials, they must hold the RCU read
|
|
* lock when reading.
|
|
*/
|
|
static inline struct group_info *get_group_info(struct group_info *gi)
|
|
{
|
|
atomic_inc(&gi->usage);
|
|
return gi;
|
|
}
|
|
|
|
/**
|
|
* put_group_info - Release a reference to a group info structure
|
|
* @group_info: The group info to release
|
|
*/
|
|
#define put_group_info(group_info) \
|
|
do { \
|
|
if (atomic_dec_and_test(&(group_info)->usage)) \
|
|
groups_free(group_info); \
|
|
} while (0)
|
|
|
|
extern struct group_info *groups_alloc(int);
|
|
extern void groups_free(struct group_info *);
|
|
extern int set_current_groups(struct group_info *);
|
|
extern int set_groups(struct cred *, struct group_info *);
|
|
extern int groups_search(const struct group_info *, gid_t);
|
|
|
|
/* access the groups "array" with this macro */
|
|
#define GROUP_AT(gi, i) \
|
|
((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK])
|
|
|
|
extern int in_group_p(gid_t);
|
|
extern int in_egroup_p(gid_t);
|
|
|
|
/*
|
|
* The security context of a task
|
|
*
|
|
* The parts of the context break down into two categories:
|
|
*
|
|
* (1) The objective context of a task. These parts are used when some other
|
|
* task is attempting to affect this one.
|
|
*
|
|
* (2) The subjective context. These details are used when the task is acting
|
|
* upon another object, be that a file, a task, a key or whatever.
|
|
*
|
|
* Note that some members of this structure belong to both categories - the
|
|
* LSM security pointer for instance.
|
|
*
|
|
* A task has two security pointers. task->real_cred points to the objective
|
|
* context that defines that task's actual details. The objective part of this
|
|
* context is used whenever that task is acted upon.
|
|
*
|
|
* task->cred points to the subjective context that defines the details of how
|
|
* that task is going to act upon another object. This may be overridden
|
|
* temporarily to point to another security context, but normally points to the
|
|
* same context as task->real_cred.
|
|
*/
|
|
struct cred {
|
|
atomic_t usage;
|
|
uid_t uid; /* real UID of the task */
|
|
gid_t gid; /* real GID of the task */
|
|
uid_t suid; /* saved UID of the task */
|
|
gid_t sgid; /* saved GID of the task */
|
|
uid_t euid; /* effective UID of the task */
|
|
gid_t egid; /* effective GID of the task */
|
|
uid_t fsuid; /* UID for VFS ops */
|
|
gid_t fsgid; /* GID for VFS ops */
|
|
unsigned securebits; /* SUID-less security management */
|
|
kernel_cap_t cap_inheritable; /* caps our children can inherit */
|
|
kernel_cap_t cap_permitted; /* caps we're permitted */
|
|
kernel_cap_t cap_effective; /* caps we can actually use */
|
|
kernel_cap_t cap_bset; /* capability bounding set */
|
|
#ifdef CONFIG_KEYS
|
|
unsigned char jit_keyring; /* default keyring to attach requested
|
|
* keys to */
|
|
struct key *thread_keyring; /* keyring private to this thread */
|
|
struct key *request_key_auth; /* assumed request_key authority */
|
|
#endif
|
|
#ifdef CONFIG_SECURITY
|
|
void *security; /* subjective LSM security */
|
|
#endif
|
|
struct user_struct *user; /* real user ID subscription */
|
|
struct group_info *group_info; /* supplementary groups for euid/fsgid */
|
|
struct rcu_head rcu; /* RCU deletion hook */
|
|
spinlock_t lock; /* lock for pointer changes */
|
|
};
|
|
|
|
extern void __put_cred(struct cred *);
|
|
extern int copy_creds(struct task_struct *, unsigned long);
|
|
|
|
/**
|
|
* get_cred - Get a reference on a set of credentials
|
|
* @cred: The credentials to reference
|
|
*
|
|
* Get a reference on the specified set of credentials. The caller must
|
|
* release the reference.
|
|
*/
|
|
static inline struct cred *get_cred(struct cred *cred)
|
|
{
|
|
atomic_inc(&cred->usage);
|
|
return cred;
|
|
}
|
|
|
|
/**
|
|
* put_cred - Release a reference to a set of credentials
|
|
* @cred: The credentials to release
|
|
*
|
|
* Release a reference to a set of credentials, deleting them when the last ref
|
|
* is released.
|
|
*/
|
|
static inline void put_cred(const struct cred *_cred)
|
|
{
|
|
struct cred *cred = (struct cred *) _cred;
|
|
if (atomic_dec_and_test(&(cred)->usage))
|
|
__put_cred(cred);
|
|
}
|
|
|
|
/**
|
|
* current_cred - Access the current task's credentials
|
|
*
|
|
* Access the credentials of the current task.
|
|
*/
|
|
#define current_cred() \
|
|
(current->cred)
|
|
|
|
/**
|
|
* __task_cred - Access another task's credentials
|
|
* @task: The task to query
|
|
*
|
|
* Access the credentials of another task. The caller must hold the
|
|
* RCU readlock.
|
|
*
|
|
* The caller must make sure task doesn't go away, either by holding a ref on
|
|
* task or by holding tasklist_lock to prevent it from being unlinked.
|
|
*/
|
|
#define __task_cred(task) \
|
|
((const struct cred *)(rcu_dereference((task)->cred)))
|
|
|
|
/**
|
|
* get_task_cred - Get another task's credentials
|
|
* @task: The task to query
|
|
*
|
|
* Get the credentials of a task, pinning them so that they can't go away.
|
|
* Accessing a task's credentials directly is not permitted.
|
|
*
|
|
* The caller must make sure task doesn't go away, either by holding a ref on
|
|
* task or by holding tasklist_lock to prevent it from being unlinked.
|
|
*/
|
|
#define get_task_cred(task) \
|
|
({ \
|
|
struct cred *__cred; \
|
|
rcu_read_lock(); \
|
|
__cred = (struct cred *) __task_cred((task)); \
|
|
get_cred(__cred); \
|
|
rcu_read_unlock(); \
|
|
__cred; \
|
|
})
|
|
|
|
/**
|
|
* get_current_cred - Get the current task's credentials
|
|
*
|
|
* Get the credentials of the current task, pinning them so that they can't go
|
|
* away. Accessing the current task's credentials directly is not permitted.
|
|
*/
|
|
#define get_current_cred() \
|
|
(get_cred(current_cred()))
|
|
|
|
/**
|
|
* get_current_user - Get the current task's user_struct
|
|
*
|
|
* Get the user record of the current task, pinning it so that it can't go
|
|
* away.
|
|
*/
|
|
#define get_current_user() \
|
|
({ \
|
|
struct user_struct *__u; \
|
|
struct cred *__cred; \
|
|
__cred = (struct cred *) current_cred(); \
|
|
__u = get_uid(__cred->user); \
|
|
__u; \
|
|
})
|
|
|
|
/**
|
|
* get_current_groups - Get the current task's supplementary group list
|
|
*
|
|
* Get the supplementary group list of the current task, pinning it so that it
|
|
* can't go away.
|
|
*/
|
|
#define get_current_groups() \
|
|
({ \
|
|
struct group_info *__groups; \
|
|
struct cred *__cred; \
|
|
__cred = (struct cred *) current_cred(); \
|
|
__groups = get_group_info(__cred->group_info); \
|
|
__groups; \
|
|
})
|
|
|
|
#define task_cred_xxx(task, xxx) \
|
|
({ \
|
|
__typeof__(task->cred->xxx) ___val; \
|
|
rcu_read_lock(); \
|
|
___val = __task_cred((task))->xxx; \
|
|
rcu_read_unlock(); \
|
|
___val; \
|
|
})
|
|
|
|
#define task_uid(task) (task_cred_xxx((task), uid))
|
|
#define task_euid(task) (task_cred_xxx((task), euid))
|
|
|
|
#define current_cred_xxx(xxx) \
|
|
({ \
|
|
current->cred->xxx; \
|
|
})
|
|
|
|
#define current_uid() (current_cred_xxx(uid))
|
|
#define current_gid() (current_cred_xxx(gid))
|
|
#define current_euid() (current_cred_xxx(euid))
|
|
#define current_egid() (current_cred_xxx(egid))
|
|
#define current_suid() (current_cred_xxx(suid))
|
|
#define current_sgid() (current_cred_xxx(sgid))
|
|
#define current_fsuid() (current_cred_xxx(fsuid))
|
|
#define current_fsgid() (current_cred_xxx(fsgid))
|
|
#define current_cap() (current_cred_xxx(cap_effective))
|
|
#define current_user() (current_cred_xxx(user))
|
|
#define current_security() (current_cred_xxx(security))
|
|
|
|
#define current_uid_gid(_uid, _gid) \
|
|
do { \
|
|
const struct cred *__cred; \
|
|
__cred = current_cred(); \
|
|
*(_uid) = __cred->uid; \
|
|
*(_gid) = __cred->gid; \
|
|
} while(0)
|
|
|
|
#define current_euid_egid(_euid, _egid) \
|
|
do { \
|
|
const struct cred *__cred; \
|
|
__cred = current_cred(); \
|
|
*(_euid) = __cred->euid; \
|
|
*(_egid) = __cred->egid; \
|
|
} while(0)
|
|
|
|
#define current_fsuid_fsgid(_fsuid, _fsgid) \
|
|
do { \
|
|
const struct cred *__cred; \
|
|
__cred = current_cred(); \
|
|
*(_fsuid) = __cred->fsuid; \
|
|
*(_fsgid) = __cred->fsgid; \
|
|
} while(0)
|
|
|
|
#endif /* _LINUX_CRED_H */
|